_ Git - ldk-c-bindings/blob - c-bindings-gen/src/types.rs

   1 // This file is Copyright its original authors, visible in version control
   2 // history.
   3 //
   4 // This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE>
   5 // or the MIT license <LICENSE-MIT>, at your option.
   6 // You may not use this file except in accordance with one or both of these
   7 // licenses.
   8
   9 use std::cell::RefCell;
  10 use std::collections::{HashMap, HashSet};
  11 use std::fs::File;
  12 use std::io::Write;
  13 use std::hash;
  14
  15 use crate::blocks::*;
  16
  17 use proc_macro2::{TokenTree, Span};
  18 use quote::format_ident;
  19 use syn::parse_quote;
  20
  21 // The following utils are used purely to build our known types maps - they break down all the
  22 // types we need to resolve to include the given object, and no more.
  23
  24 pub fn first_seg_self<'a>(t: &'a syn::Type) -> Option<impl Iterator<Item=&syn::PathSegment> + 'a> {
  25         match t {
  26                 syn::Type::Path(p) => {
  27                         if p.qself.is_some() || p.path.leading_colon.is_some() {
  28                                 return None;
  29                         }
  30                         let mut segs = p.path.segments.iter();
  31                         let ty = segs.next().unwrap();
  32                         if !ty.arguments.is_empty() { return None; }
  33                         if format!("{}", ty.ident) == "Self" {
  34                                 Some(segs)
  35                         } else { None }
  36                 },
  37                 _ => None,
  38         }
  39 }
  40
  41 pub fn get_single_remaining_path_seg<'a, I: Iterator<Item=&'a syn::PathSegment>>(segs: &mut I) -> Option<&'a syn::Ident> {
  42         if let Some(ty) = segs.next() {
  43                 if !ty.arguments.is_empty() { unimplemented!(); }
  44                 if segs.next().is_some() { return None; }
  45                 Some(&ty.ident)
  46         } else { None }
  47 }
  48
  49 pub fn first_seg_is_stdlib(first_seg_str: &str) -> bool {
  50         first_seg_str == "std" || first_seg_str == "core" || first_seg_str == "alloc"
  51 }
  52
  53 pub fn single_ident_generic_path_to_ident(p: &syn::Path) -> Option<&syn::Ident> {
  54         if p.segments.len() == 1 {
  55                 Some(&p.segments.iter().next().unwrap().ident)
  56         } else { None }
  57 }
  58
  59 pub fn path_matches_nongeneric(p: &syn::Path, exp: &[&str]) -> bool {
  60         if p.segments.len() != exp.len() { return false; }
  61         for (seg, e) in p.segments.iter().zip(exp.iter()) {
  62                 if seg.arguments != syn::PathArguments::None { return false; }
  63                 if &format!("{}", seg.ident) != *e { return false; }
  64         }
  65         true
  66 }
  67
  68 pub fn string_path_to_syn_path(path: &str) -> syn::Path {
  69         let mut segments = syn::punctuated::Punctuated::new();
  70         for seg in path.split("::") {
  71                 segments.push(syn::PathSegment {
  72                         ident: syn::Ident::new(seg, Span::call_site()),
  73                         arguments: syn::PathArguments::None,
  74                 });
  75         }
  76         syn::Path { leading_colon: Some(syn::Token![::](Span::call_site())), segments }
  77 }
  78
  79 #[derive(Debug, PartialEq)]
  80 pub enum ExportStatus {
  81         Export,
  82         NoExport,
  83         TestOnly,
  84         /// This is used only for traits to indicate that users should not be able to implement their
  85         /// own version of a trait, but we should export Rust implementations of the trait (and the
  86         /// trait itself).
  87         /// Concretly, this means that we do not implement the Rust trait for the C trait struct.
  88         NotImplementable,
  89 }
  90 /// Gets the ExportStatus of an object (struct, fn, etc) given its attributes.
  91 pub fn export_status(attrs: &[syn::Attribute]) -> ExportStatus {
  92         for attr in attrs.iter() {
  93                 let tokens_clone = attr.tokens.clone();
  94                 let mut token_iter = tokens_clone.into_iter();
  95                 if let Some(token) = token_iter.next() {
  96                         match token {
  97                                 TokenTree::Punct(c) if c.as_char() == '=' => {
  98                                         // Really not sure where syn gets '=' from here -
  99                                         // it somehow represents '///' or '//!'
 100                                 },
 101                                 TokenTree::Group(g) => {
 102                                         if format!("{}", single_ident_generic_path_to_ident(&attr.path).unwrap()) == "cfg" {
 103                                                 let mut iter = g.stream().into_iter();
 104                                                 if let TokenTree::Ident(i) = iter.next().unwrap() {
 105                                                         if i == "any" {
 106                                                                 // #[cfg(any(test, feature = ""))]
 107                                                                 if let TokenTree::Group(g) = iter.next().unwrap() {
 108                                                                         let mut all_test = true;
 109                                                                         for token in g.stream().into_iter() {
 110                                                                                 if let TokenTree::Ident(i) = token {
 111                                                                                         match format!("{}", i).as_str() {
 112                                                                                                 "test" => {},
 113                                                                                                 "feature" => {},
 114                                                                                                 _ => all_test = false,
 115                                                                                         }
 116                                                                                 } else if let TokenTree::Literal(lit) = token {
 117                                                                                         if format!("{}", lit) != "fuzztarget" {
 118                                                                                                 all_test = false;
 119                                                                                         }
 120                                                                                 }
 121                                                                         }
 122                                                                         if all_test { return ExportStatus::TestOnly; }
 123                                                                 }
 124                                                         } else if i == "test" {
 125                                                                 return ExportStatus::TestOnly;
 126                                                         }
 127                                                 }
 128                                         }
 129                                         continue; // eg #[derive()]
 130                                 },
 131                                 _ => unimplemented!(),
 132                         }
 133                 } else { continue; }
 134                 match token_iter.next().unwrap() {
 135                         TokenTree::Literal(lit) => {
 136                                 let line = format!("{}", lit);
 137                                 if line.contains("(C-not exported)") || line.contains("This is not exported to bindings users") {
 138                                         return ExportStatus::NoExport;
 139                                 } else if line.contains("(C-not implementable)") {
 140                                         return ExportStatus::NotImplementable;
 141                                 }
 142                         },
 143                         _ => unimplemented!(),
 144                 }
 145         }
 146         ExportStatus::Export
 147 }
 148
 149 pub fn assert_simple_bound(bound: &syn::TraitBound) {
 150         if bound.paren_token.is_some() { unimplemented!(); }
 151         if let syn::TraitBoundModifier::Maybe(_) = bound.modifier { unimplemented!(); }
 152 }
 153
 154 /// Returns true if the enum will be mapped as an opaue (ie struct with a pointer to the underlying
 155 /// type), otherwise it is mapped into a transparent, C-compatible version of itself.
 156 pub fn is_enum_opaque(e: &syn::ItemEnum) -> bool {
 157         for var in e.variants.iter() {
 158                 if let syn::Fields::Named(fields) = &var.fields {
 159                         for field in fields.named.iter() {
 160                                 match export_status(&field.attrs) {
 161                                         ExportStatus::Export|ExportStatus::TestOnly => {},
 162                                         ExportStatus::NotImplementable => panic!("(C-not implementable) should only appear on traits!"),
 163                                         ExportStatus::NoExport => return true,
 164                                 }
 165                         }
 166                 } else if let syn::Fields::Unnamed(fields) = &var.fields {
 167                         for field in fields.unnamed.iter() {
 168                                 match export_status(&field.attrs) {
 169                                         ExportStatus::Export|ExportStatus::TestOnly => {},
 170                                         ExportStatus::NotImplementable => panic!("(C-not implementable) should only appear on traits!"),
 171                                         ExportStatus::NoExport => return true,
 172                                 }
 173                         }
 174                 }
 175         }
 176         false
 177 }
 178
 179 /// A stack of sets of generic resolutions.
 180 ///
 181 /// This tracks the template parameters for a function, struct, or trait, allowing resolution into
 182 /// a concrete type. By pushing a new context onto the stack, this can track a function's template
 183 /// parameters inside of a generic struct or trait.
 184 ///
 185 /// It maps both direct types as well as Deref<Target = X>, mapping them via the provided
 186 /// TypeResolver's resolve_path function (ie traits map to the concrete jump table, structs to the
 187 /// concrete C container struct, etc).
 188 #[must_use]
 189 pub struct GenericTypes<'a, 'b> {
 190         self_ty: Option<String>,
 191         parent: Option<&'b GenericTypes<'b, 'b>>,
 192         typed_generics: HashMap<&'a syn::Ident, String>,
 193         default_generics: HashMap<&'a syn::Ident, (syn::Type, syn::Type, syn::Type)>,
 194 }
 195 impl<'a, 'p: 'a> GenericTypes<'a, 'p> {
 196         pub fn new(self_ty: Option<String>) -> Self {
 197                 Self { self_ty, parent: None, typed_generics: HashMap::new(), default_generics: HashMap::new(), }
 198         }
 199
 200         /// push a new context onto the stack, allowing for a new set of generics to be learned which
 201         /// will override any lower contexts, but which will still fall back to resoltion via lower
 202         /// contexts.
 203         pub fn push_ctx<'c>(&'c self) -> GenericTypes<'a, 'c> {
 204                 GenericTypes { self_ty: None, parent: Some(self), typed_generics: HashMap::new(), default_generics: HashMap::new(), }
 205         }
 206
 207         /// Learn the generics in generics in the current context, given a TypeResolver.
 208         pub fn learn_generics_with_impls<'b, 'c>(&mut self, generics: &'a syn::Generics, impld_generics: &'a syn::PathArguments, types: &'b TypeResolver<'a, 'c>) -> bool {
 209                 let mut new_typed_generics = HashMap::new();
 210                 // First learn simple generics...
 211                 for (idx, generic) in generics.params.iter().enumerate() {
 212                         match generic {
 213                                 syn::GenericParam::Type(type_param) => {
 214                                         let mut non_lifetimes_processed = false;
 215                                         'bound_loop: for bound in type_param.bounds.iter() {
 216                                                 if let syn::TypeParamBound::Trait(trait_bound) = bound {
 217                                                         if let Some(ident) = single_ident_generic_path_to_ident(&trait_bound.path) {
 218                                                                 match &format!("{}", ident) as &str { "Send" => continue, "Sync" => continue, "Sized" => continue, _ => {} }
 219                                                         }
 220                                                         if path_matches_nongeneric(&trait_bound.path, &["core", "clone", "Clone"]) { continue; }
 221
 222                                                         assert_simple_bound(&trait_bound);
 223                                                         if let Some(path) = types.maybe_resolve_path(&trait_bound.path, None) {
 224                                                                 if types.skip_path(&path) { continue; }
 225                                                                 if path == "Sized" { continue; }
 226                                                                 if non_lifetimes_processed { return false; }
 227                                                                 non_lifetimes_processed = true;
 228                                                                 if path != "std::ops::Deref" && path != "core::ops::Deref" &&
 229                                                                         path != "std::ops::DerefMut" && path != "core::ops::DerefMut"  {
 230                                                                         let p = string_path_to_syn_path(&path);
 231                                                                         let ref_ty = parse_quote!(&#p);
 232                                                                         let mut_ref_ty = parse_quote!(&mut #p);
 233                                                                         self.default_generics.insert(&type_param.ident, (syn::Type::Path(syn::TypePath { qself: None, path: p }), ref_ty, mut_ref_ty));
 234                                                                         new_typed_generics.insert(&type_param.ident, Some(path));
 235                                                                 } else {
 236                                                                         // If we're templated on Deref<Target = ConcreteThing>, store
 237                                                                         // the reference type in `default_generics` which handles full
 238                                                                         // types and not just paths.
 239                                                                         if let syn::PathArguments::AngleBracketed(ref args) =
 240                                                                                         trait_bound.path.segments[0].arguments {
 241                                                                                 assert_eq!(trait_bound.path.segments.len(), 1);
 242                                                                                 for subargument in args.args.iter() {
 243                                                                                         match subargument {
 244                                                                                                 syn::GenericArgument::Lifetime(_) => {},
 245                                                                                                 syn::GenericArgument::Binding(ref b) => {
 246                                                                                                         if &format!("{}", b.ident) != "Target" { return false; }
 247                                                                                                         let default = &b.ty;
 248                                                                                                         self.default_generics.insert(&type_param.ident, (parse_quote!(&#default), parse_quote!(&#default), parse_quote!(&mut #default)));
 249                                                                                                         break 'bound_loop;
 250                                                                                                 },
 251                                                                                                 _ => unimplemented!(),
 252                                                                                         }
 253                                                                                 }
 254                                                                         } else {
 255                                                                                 new_typed_generics.insert(&type_param.ident, None);
 256                                                                         }
 257                                                                 }
 258                                                         }
 259                                                 }
 260                                         }
 261                                         if let Some(default) = type_param.default.as_ref() {
 262                                                 assert!(type_param.bounds.is_empty());
 263                                                 self.default_generics.insert(&type_param.ident, (default.clone(), parse_quote!(&#default), parse_quote!(&mut #default)));
 264                                         } else if type_param.bounds.is_empty() {
 265                                                 if let syn::PathArguments::AngleBracketed(args) = impld_generics {
 266                                                         match &args.args[idx] {
 267                                                                 syn::GenericArgument::Type(ty) => {
 268                                                                         self.default_generics.insert(&type_param.ident, (ty.clone(), parse_quote!(&#ty), parse_quote!(&mut #ty)));
 269                                                                 }
 270                                                                 _ => unimplemented!(),
 271                                                         }
 272                                                 }
 273                                         }
 274                                 },
 275                                 _ => {},
 276                         }
 277                 }
 278                 // Then find generics where we are required to pass a Deref<Target=X> and pretend its just X.
 279                 if let Some(wh) = &generics.where_clause {
 280                         for pred in wh.predicates.iter() {
 281                                 if let syn::WherePredicate::Type(t) = pred {
 282                                         if let syn::Type::Path(p) = &t.bounded_ty {
 283                                                 if first_seg_self(&t.bounded_ty).is_some() && p.path.segments.len() == 1 { continue; }
 284                                                 if p.qself.is_some() { return false; }
 285                                                 if p.path.leading_colon.is_some() { return false; }
 286                                                 let mut p_iter = p.path.segments.iter();
 287                                                 let p_ident = &p_iter.next().unwrap().ident;
 288                                                 if let Some(gen) = new_typed_generics.get_mut(p_ident) {
 289                                                         if gen.is_some() { return false; }
 290                                                         if &format!("{}", p_iter.next().unwrap().ident) != "Target" {return false; }
 291
 292                                                         let mut non_lifetimes_processed = false;
 293                                                         for bound in t.bounds.iter() {
 294                                                                 if let syn::TypeParamBound::Trait(trait_bound) = bound {
 295                                                                         if let Some(id) = trait_bound.path.get_ident() {
 296                                                                                 if format!("{}", id) == "Sized" { continue; }
 297                                                                                 if format!("{}", id) == "Send" { continue; }
 298                                                                                 if format!("{}", id) == "Sync" { continue; }
 299                                                                         }
 300                                                                         if non_lifetimes_processed { return false; }
 301                                                                         non_lifetimes_processed = true;
 302                                                                         assert_simple_bound(&trait_bound);
 303                                                                         let resolved = types.resolve_path(&trait_bound.path, None);
 304                                                                         let ty = syn::Type::Path(syn::TypePath {
 305                                                                                 qself: None, path: string_path_to_syn_path(&resolved)
 306                                                                         });
 307                                                                         let ref_ty = parse_quote!(&#ty);
 308                                                                         let mut_ref_ty = parse_quote!(&mut #ty);
 309                                                                         if types.crate_types.traits.get(&resolved).is_some() {
 310                                                                                 self.default_generics.insert(p_ident, (ty, ref_ty, mut_ref_ty));
 311                                                                         } else {
 312                                                                                 self.default_generics.insert(p_ident, (ref_ty.clone(), ref_ty, mut_ref_ty));
 313                                                                         }
 314
 315                                                                         *gen = Some(resolved);
 316                                                                 }
 317                                                         }
 318                                                 } else { return false; }
 319                                         } else { return false; }
 320                                 }
 321                         }
 322                 }
 323                 for (key, value) in new_typed_generics.drain() {
 324                         if let Some(v) = value {
 325                                 assert!(self.typed_generics.insert(key, v).is_none());
 326                         } else { return false; }
 327                 }
 328                 true
 329         }
 330
 331         /// Learn the generics in generics in the current context, given a TypeResolver.
 332         pub fn learn_generics<'b, 'c>(&mut self, generics: &'a syn::Generics, types: &'b TypeResolver<'a, 'c>) -> bool {
 333                 self.learn_generics_with_impls(generics, &syn::PathArguments::None, types)
 334         }
 335
 336         /// Learn the associated types from the trait in the current context.
 337         pub fn learn_associated_types<'b, 'c>(&mut self, t: &'a syn::ItemTrait, types: &'b TypeResolver<'a, 'c>) {
 338                 for item in t.items.iter() {
 339                         match item {
 340                                 &syn::TraitItem::Type(ref t) => {
 341                                         if t.default.is_some() || t.generics.lt_token.is_some() { unimplemented!(); }
 342                                         let mut bounds_iter = t.bounds.iter();
 343                                         loop {
 344                                                 match bounds_iter.next().unwrap() {
 345                                                         syn::TypeParamBound::Trait(tr) => {
 346                                                                 assert_simple_bound(&tr);
 347                                                                 if let Some(path) = types.maybe_resolve_path(&tr.path, None) {
 348                                                                         if types.skip_path(&path) { continue; }
 349                                                                         // In general we handle Deref<Target=X> as if it were just X (and
 350                                                                         // implement Deref<Target=Self> for relevant types). We don't
 351                                                                         // bother to implement it for associated types, however, so we just
 352                                                                         // ignore such bounds.
 353                                                                         if path != "std::ops::Deref" && path != "core::ops::Deref" &&
 354                                                                         path != "std::ops::DerefMut" && path != "core::ops::DerefMut" {
 355                                                                                 self.typed_generics.insert(&t.ident, path);
 356                                                                         } else {
 357                                                                                 let last_seg_args = &tr.path.segments.last().unwrap().arguments;
 358                                                                                 if let syn::PathArguments::AngleBracketed(args) = last_seg_args {
 359                                                                                         assert_eq!(args.args.len(), 1);
 360                                                                                         if let syn::GenericArgument::Binding(binding) = &args.args[0] {
 361                                                                                                 assert_eq!(format!("{}", binding.ident), "Target");
 362                                                                                                 if let syn::Type::Path(p) = &binding.ty {
 363                                                                                                         // Note that we are assuming the order of type
 364                                                                                                         // declarations here, but that should be easy
 365                                                                                                         // to handle.
 366                                                                                                         let real_path = self.maybe_resolve_path(&p.path).unwrap();
 367                                                                                                         self.typed_generics.insert(&t.ident, real_path.clone());
 368                                                                                                 } else { unimplemented!(); }
 369                                                                                         } else { unimplemented!(); }
 370                                                                                 } else { unimplemented!(); }
 371                                                                         }
 372                                                                 } else { unimplemented!(); }
 373                                                                 for bound in bounds_iter {
 374                                                                         if let syn::TypeParamBound::Trait(t) = bound {
 375                                                                                 // We only allow for `?Sized` here.
 376                                                                                 assert_eq!(t.path.segments.len(), 1);
 377                                                                                 assert_eq!(format!("{}", t.path.segments[0].ident), "Sized");
 378                                                                         }
 379                                                                 }
 380                                                                 break;
 381                                                         },
 382                                                         syn::TypeParamBound::Lifetime(_) => {},
 383                                                 }
 384                                         }
 385                                 },
 386                                 _ => {},
 387                         }
 388                 }
 389         }
 390
 391         /// Attempt to resolve a Path as a generic parameter and return the full path. as both a string
 392         /// and syn::Path.
 393         pub fn maybe_resolve_path<'b>(&'b self, path: &syn::Path) -> Option<&'b String> {
 394                 if let Some(ident) = path.get_ident() {
 395                         if let Some(ty) = &self.self_ty {
 396                                 if format!("{}", ident) == "Self" {
 397                                         return Some(&ty);
 398                                 }
 399                         }
 400                         if let Some(res) = self.typed_generics.get(ident) {
 401                                 return Some(res);
 402                         }
 403                 } else {
 404                         // Associated types are usually specified as "Self::Generic", so we check for that
 405                         // explicitly here.
 406                         let mut it = path.segments.iter();
 407                         if path.segments.len() == 2 && format!("{}", it.next().unwrap().ident) == "Self" {
 408                                 let ident = &it.next().unwrap().ident;
 409                                 if let Some(res) = self.typed_generics.get(ident) {
 410                                         return Some(res);
 411                                 }
 412                         }
 413                 }
 414                 if let Some(parent) = self.parent {
 415                         parent.maybe_resolve_path(path)
 416                 } else {
 417                         None
 418                 }
 419         }
 420 }
 421
 422 pub trait ResolveType<'a> { fn resolve_type(&'a self, ty: &'a syn::Type) -> &'a syn::Type; }
 423 impl<'a, 'b, 'c: 'a + 'b> ResolveType<'c> for Option<&GenericTypes<'a, 'b>> {
 424         fn resolve_type(&'c self, ty: &'c syn::Type) -> &'c syn::Type {
 425                 if let Some(us) = self {
 426                         match ty {
 427                                 syn::Type::Path(p) => {
 428                                         if let Some(ident) = p.path.get_ident() {
 429                                                 if let Some((ty, _, _)) = us.default_generics.get(ident) {
 430                                                         return self.resolve_type(ty);
 431                                                 }
 432                                         }
 433                                 },
 434                                 syn::Type::Reference(syn::TypeReference { elem, mutability, .. }) => {
 435                                         if let syn::Type::Path(p) = &**elem {
 436                                                 if let Some(ident) = p.path.get_ident() {
 437                                                         if let Some((_, refty, mut_ref_ty)) = us.default_generics.get(ident) {
 438                                                                 if mutability.is_some() {
 439                                                                         return self.resolve_type(mut_ref_ty);
 440                                                                 } else {
 441                                                                         return self.resolve_type(refty);
 442                                                                 }
 443                                                         }
 444                                                 }
 445                                         }
 446                                 }
 447                                 _ => {},
 448                         }
 449                         us.parent.resolve_type(ty)
 450                 } else { ty }
 451         }
 452 }
 453
 454 #[derive(Clone, PartialEq)]
 455 // The type of declaration and the object itself
 456 pub enum DeclType<'a> {
 457         MirroredEnum,
 458         Trait(&'a syn::ItemTrait),
 459         StructImported { generics: &'a syn::Generics  },
 460         StructIgnored,
 461         EnumIgnored { generics: &'a syn::Generics },
 462 }
 463
 464 pub struct ImportResolver<'mod_lifetime, 'crate_lft: 'mod_lifetime> {
 465         pub crate_name: &'mod_lifetime str,
 466         library: &'crate_lft FullLibraryAST,
 467         module_path: &'mod_lifetime str,
 468         imports: HashMap<syn::Ident, (String, syn::Path)>,
 469         declared: HashMap<syn::Ident, DeclType<'crate_lft>>,
 470         priv_modules: HashSet<syn::Ident>,
 471 }
 472 impl<'mod_lifetime, 'crate_lft: 'mod_lifetime> ImportResolver<'mod_lifetime, 'crate_lft> {
 473         fn walk_use_intern<F: FnMut(syn::Ident, (String, syn::Path))>(
 474                 crate_name: &str, module_path: &str, dependencies: &HashSet<syn::Ident>, u: &syn::UseTree,
 475                 partial_path: &str,
 476                 mut path: syn::punctuated::Punctuated<syn::PathSegment, syn::token::Colon2>, handle_use: &mut F
 477         ) {
 478                 let new_path;
 479                 macro_rules! push_path {
 480                         ($ident: expr, $path_suffix: expr) => {
 481                                 if partial_path == "" && format!("{}", $ident) == "super" {
 482                                         let mut mod_iter = module_path.rsplitn(2, "::");
 483                                         mod_iter.next().unwrap();
 484                                         let super_mod = mod_iter.next().unwrap();
 485                                         new_path = format!("{}{}", super_mod, $path_suffix);
 486                                         assert_eq!(path.len(), 0);
 487                                         for module in super_mod.split("::") {
 488                                                 path.push(syn::PathSegment { ident: syn::Ident::new(module, Span::call_site()), arguments: syn::PathArguments::None });
 489                                         }
 490                                 } else if partial_path == "" && format!("{}", $ident) == "self" {
 491                                         new_path = format!("{}{}", module_path, $path_suffix);
 492                                         for module in module_path.split("::") {
 493                                                 path.push(syn::PathSegment { ident: syn::Ident::new(module, Span::call_site()), arguments: syn::PathArguments::None });
 494                                         }
 495                                 } else if partial_path == "" && format!("{}", $ident) == "crate" {
 496                                         new_path = format!("{}{}", crate_name, $path_suffix);
 497                                         let crate_name_ident = format_ident!("{}", crate_name);
 498                                         path.push(parse_quote!(#crate_name_ident));
 499                                 } else if partial_path == "" && !dependencies.contains(&$ident) {
 500                                         new_path = format!("{}::{}{}", module_path, $ident, $path_suffix);
 501                                         for module in module_path.split("::") {
 502                                                 path.push(syn::PathSegment { ident: syn::Ident::new(module, Span::call_site()), arguments: syn::PathArguments::None });
 503                                         }
 504                                         let ident_str = format_ident!("{}", $ident);
 505                                         path.push(parse_quote!(#ident_str));
 506                                 } else if format!("{}", $ident) == "self" {
 507                                         let mut path_iter = partial_path.rsplitn(2, "::");
 508                                         path_iter.next().unwrap();
 509                                         new_path = path_iter.next().unwrap().to_owned();
 510                                 } else {
 511                                         new_path = format!("{}{}{}", partial_path, $ident, $path_suffix);
 512                                 }
 513                                 let ident = &$ident;
 514                                 path.push(parse_quote!(#ident));
 515                         }
 516                 }
 517                 match u {
 518                         syn::UseTree::Path(p) => {
 519                                 push_path!(p.ident, "::");
 520                                 Self::walk_use_intern(crate_name, module_path, dependencies, &p.tree, &new_path, path, handle_use);
 521                         },
 522                         syn::UseTree::Name(n) => {
 523                                 push_path!(n.ident, "");
 524                                 let imported_ident = syn::Ident::new(new_path.rsplitn(2, "::").next().unwrap(), Span::call_site());
 525                                 handle_use(imported_ident, (new_path, syn::Path { leading_colon: Some(syn::Token![::](Span::call_site())), segments: path }));
 526                         },
 527                         syn::UseTree::Group(g) => {
 528                                 for i in g.items.iter() {
 529                                         Self::walk_use_intern(crate_name, module_path, dependencies, i, partial_path, path.clone(), handle_use);
 530                                 }
 531                         },
 532                         syn::UseTree::Rename(r) => {
 533                                 push_path!(r.ident, "");
 534                                 handle_use(r.rename.clone(), (new_path, syn::Path { leading_colon: Some(syn::Token![::](Span::call_site())), segments: path }));
 535                         },
 536                         syn::UseTree::Glob(_) => {
 537                                 eprintln!("Ignoring * use for {} - this may result in resolution failures", partial_path);
 538                         },
 539                 }
 540         }
 541
 542         fn process_use_intern(crate_name: &str, module_path: &str, dependencies: &HashSet<syn::Ident>,
 543                 imports: &mut HashMap<syn::Ident, (String, syn::Path)>, u: &syn::UseTree, partial_path: &str,
 544                 path: syn::punctuated::Punctuated<syn::PathSegment, syn::token::Colon2>
 545         ) {
 546                 Self::walk_use_intern(crate_name, module_path, dependencies, u, partial_path, path,
 547                         &mut |k, v| { imports.insert(k, v); });
 548         }
 549
 550         fn process_use(crate_name: &str, module_path: &str, dependencies: &HashSet<syn::Ident>, imports: &mut HashMap<syn::Ident, (String, syn::Path)>, u: &syn::ItemUse) {
 551                 if u.leading_colon.is_some() { eprintln!("Ignoring leading-colon use!"); return; }
 552                 Self::process_use_intern(crate_name, module_path, dependencies, imports, &u.tree, "", syn::punctuated::Punctuated::new());
 553         }
 554
 555         fn insert_primitive(imports: &mut HashMap<syn::Ident, (String, syn::Path)>, id: &str) {
 556                 let ident = format_ident!("{}", id);
 557                 let path = parse_quote!(#ident);
 558                 imports.insert(ident, (id.to_owned(), path));
 559         }
 560
 561         pub fn new(crate_name: &'mod_lifetime str, library: &'crate_lft FullLibraryAST, module_path: &'mod_lifetime str, contents: &'crate_lft [syn::Item]) -> Self {
 562                 Self::from_borrowed_items(crate_name, library, module_path, &contents.iter().map(|a| a).collect::<Vec<_>>())
 563         }
 564         pub fn from_borrowed_items(crate_name: &'mod_lifetime str, library: &'crate_lft FullLibraryAST, module_path: &'mod_lifetime str, contents: &[&'crate_lft syn::Item]) -> Self {
 565                 let mut imports = HashMap::new();
 566                 // Add primitives to the "imports" list:
 567                 Self::insert_primitive(&mut imports, "bool");
 568                 Self::insert_primitive(&mut imports, "u128");
 569                 Self::insert_primitive(&mut imports, "i64");
 570                 Self::insert_primitive(&mut imports, "f64");
 571                 Self::insert_primitive(&mut imports, "u64");
 572                 Self::insert_primitive(&mut imports, "u32");
 573                 Self::insert_primitive(&mut imports, "u16");
 574                 Self::insert_primitive(&mut imports, "u8");
 575                 Self::insert_primitive(&mut imports, "usize");
 576                 Self::insert_primitive(&mut imports, "str");
 577                 Self::insert_primitive(&mut imports, "String");
 578
 579                 // These are here to allow us to print native Rust types in trait fn impls even if we don't
 580                 // have C mappings:
 581                 Self::insert_primitive(&mut imports, "Result");
 582                 Self::insert_primitive(&mut imports, "Vec");
 583                 Self::insert_primitive(&mut imports, "Option");
 584
 585                 let mut declared = HashMap::new();
 586                 let mut priv_modules = HashSet::new();
 587
 588                 for item in contents.iter() {
 589                         match item {
 590                                 syn::Item::Use(u) => Self::process_use(crate_name, module_path, &library.dependencies, &mut imports, &u),
 591                                 syn::Item::Struct(s) => {
 592                                         if let syn::Visibility::Public(_) = s.vis {
 593                                                 match export_status(&s.attrs) {
 594                                                         ExportStatus::Export => { declared.insert(s.ident.clone(), DeclType::StructImported { generics: &s.generics }); },
 595                                                         ExportStatus::NoExport => { declared.insert(s.ident.clone(), DeclType::StructIgnored); },
 596                                                         ExportStatus::TestOnly => continue,
 597                                                         ExportStatus::NotImplementable => panic!("(C-not implementable) should only appear on traits!"),
 598                                                 }
 599                                         }
 600                                 },
 601                                 syn::Item::Type(t) if export_status(&t.attrs) == ExportStatus::Export => {
 602                                         if let syn::Visibility::Public(_) = t.vis {
 603                                                 declared.insert(t.ident.clone(), DeclType::StructImported { generics: &t.generics });
 604                                         }
 605                                 },
 606                                 syn::Item::Enum(e) => {
 607                                         if let syn::Visibility::Public(_) = e.vis {
 608                                                 match export_status(&e.attrs) {
 609                                                         ExportStatus::Export if is_enum_opaque(e) => { declared.insert(e.ident.clone(), DeclType::EnumIgnored { generics: &e.generics }); },
 610                                                         ExportStatus::Export => { declared.insert(e.ident.clone(), DeclType::MirroredEnum); },
 611                                                         ExportStatus::NotImplementable => panic!("(C-not implementable) should only appear on traits!"),
 612                                                         _ => continue,
 613                                                 }
 614                                         }
 615                                 },
 616                                 syn::Item::Trait(t) => {
 617                                         if let syn::Visibility::Public(_) = t.vis {
 618                                                 declared.insert(t.ident.clone(), DeclType::Trait(t));
 619                                         }
 620                                 },
 621                                 syn::Item::Mod(m) => {
 622                                         priv_modules.insert(m.ident.clone());
 623                                 },
 624                                 _ => {},
 625                         }
 626                 }
 627
 628                 Self { crate_name, library, module_path, imports, declared, priv_modules }
 629         }
 630
 631         pub fn maybe_resolve_declared(&self, id: &syn::Ident) -> Option<&DeclType<'crate_lft>> {
 632                 self.declared.get(id)
 633         }
 634
 635         pub fn maybe_resolve_ident(&self, id: &syn::Ident) -> Option<String> {
 636                 if let Some((imp, _)) = self.imports.get(id) {
 637                         Some(imp.clone())
 638                 } else if self.declared.get(id).is_some() {
 639                         Some(self.module_path.to_string() + "::" + &format!("{}", id))
 640                 } else { None }
 641         }
 642
 643         fn maybe_resolve_imported_path(&self, p: &syn::Path, generics: Option<&GenericTypes>) -> Option<String> {
 644                 if let Some(gen_types) = generics {
 645                         if let Some(resp) = gen_types.maybe_resolve_path(p) {
 646                                 return Some(resp.clone());
 647                         }
 648                 }
 649
 650                 if p.leading_colon.is_some() {
 651                         let mut res: String = p.segments.iter().enumerate().map(|(idx, seg)| {
 652                                 format!("{}{}", if idx == 0 { "" } else { "::" }, seg.ident)
 653                         }).collect();
 654                         let firstseg = p.segments.iter().next().unwrap();
 655                         if !self.library.dependencies.contains(&firstseg.ident) {
 656                                 res = self.crate_name.to_owned() + "::" + &res;
 657                         }
 658                         Some(res)
 659                 } else if let Some(id) = p.get_ident() {
 660                         self.maybe_resolve_ident(id)
 661                 } else {
 662                         if p.segments.len() == 1 {
 663                                 let seg = p.segments.iter().next().unwrap();
 664                                 return self.maybe_resolve_ident(&seg.ident);
 665                         }
 666                         let mut seg_iter = p.segments.iter();
 667                         let first_seg = seg_iter.next().unwrap();
 668                         let remaining: String = seg_iter.map(|seg| {
 669                                 format!("::{}", seg.ident)
 670                         }).collect();
 671                         let first_seg_str = format!("{}", first_seg.ident);
 672                         if let Some((imp, _)) = self.imports.get(&first_seg.ident) {
 673                                 if remaining != "" {
 674                                         Some(imp.clone() + &remaining)
 675                                 } else {
 676                                         Some(imp.clone())
 677                                 }
 678                         } else if let Some(_) = self.priv_modules.get(&first_seg.ident) {
 679                                 Some(format!("{}::{}{}", self.module_path, first_seg.ident, remaining))
 680                         } else if first_seg_is_stdlib(&first_seg_str) || self.library.dependencies.contains(&first_seg.ident) {
 681                                 Some(first_seg_str + &remaining)
 682                         } else if first_seg_str == "crate" {
 683                                 Some(self.crate_name.to_owned() + &remaining)
 684                         } else if self.library.modules.get(&format!("{}::{}", self.module_path, first_seg.ident)).is_some() {
 685                                 Some(format!("{}::{}{}", self.module_path, first_seg.ident, remaining))
 686                         } else { None }
 687                 }
 688         }
 689
 690         pub fn maybe_resolve_path(&self, p: &syn::Path, generics: Option<&GenericTypes>) -> Option<String> {
 691                 self.maybe_resolve_imported_path(p, generics).map(|mut path| {
 692                         if path == "core::ops::Deref" || path == "core::ops::DerefMut" {
 693                                 let last_seg = p.segments.last().unwrap();
 694                                 if let syn::PathArguments::AngleBracketed(args) = &last_seg.arguments {
 695                                         assert_eq!(args.args.len(), 1);
 696                                         if let syn::GenericArgument::Binding(binding) = &args.args[0] {
 697                                                 if let syn::Type::Path(p) = &binding.ty {
 698                                                         if let Some(inner_ty) = self.maybe_resolve_path(&p.path, generics) {
 699                                                                 let mut module_riter = inner_ty.rsplitn(2, "::");
 700                                                                 let ty_ident = module_riter.next().unwrap();
 701                                                                 let module_name = module_riter.next().unwrap();
 702                                                                 let module = self.library.modules.get(module_name).unwrap();
 703                                                                 for item in module.items.iter() {
 704                                                                         match item {
 705                                                                                 syn::Item::Trait(t) => {
 706                                                                                         if t.ident == ty_ident {
 707                                                                                                 path = inner_ty;
 708                                                                                                 break;
 709                                                                                         }
 710                                                                                 },
 711                                                                                 _ => {}
 712                                                                         }
 713                                                                 }
 714                                                         }
 715                                                 } else { unimplemented!(); }
 716                                         } else { unimplemented!(); }
 717                                 }
 718                         }
 719                         loop {
 720                                 // Now that we've resolved the path to the path as-imported, check whether the path
 721                                 // is actually a pub(.*) use statement and map it to the real path.
 722                                 let path_tmp = path.clone();
 723                                 let crate_name = path_tmp.splitn(2, "::").next().unwrap();
 724                                 let mut module_riter = path_tmp.rsplitn(2, "::");
 725                                 let obj = module_riter.next().unwrap();
 726                                 if let Some(module_path) = module_riter.next() {
 727                                         if let Some(m) = self.library.modules.get(module_path) {
 728                                                 for item in m.items.iter() {
 729                                                         if let syn::Item::Use(syn::ItemUse { vis, tree, .. }) = item {
 730                                                                 match vis {
 731                                                                         syn::Visibility::Public(_)|
 732                                                                         syn::Visibility::Crate(_)|
 733                                                                         syn::Visibility::Restricted(_) => {
 734                                                                                 Self::walk_use_intern(crate_name, module_path,
 735                                                                                         &self.library.dependencies, tree, "",
 736                                                                                         syn::punctuated::Punctuated::new(), &mut |ident, (use_path, _)| {
 737                                                                                                 if format!("{}", ident) == obj {
 738                                                                                                         path = use_path;
 739                                                                                                 }
 740                                                                                 });
 741                                                                         },
 742                                                                         syn::Visibility::Inherited => {},
 743                                                                 }
 744                                                         }
 745                                                 }
 746                                         }
 747                                 }
 748                                 break;
 749                         }
 750                         path
 751                 })
 752         }
 753
 754         /// Map all the Paths in a Type into absolute paths given a set of imports (generated via process_use_intern)
 755         pub fn resolve_imported_refs(&self, mut ty: syn::Type) -> syn::Type {
 756                 match &mut ty {
 757                         syn::Type::Path(p) => {
 758                                 if p.path.segments.len() != 1 { unimplemented!(); }
 759                                 let mut args = p.path.segments[0].arguments.clone();
 760                                 if let syn::PathArguments::AngleBracketed(ref mut generics) = &mut args {
 761                                         for arg in generics.args.iter_mut() {
 762                                                 if let syn::GenericArgument::Type(ref mut t) = arg {
 763                                                         *t = self.resolve_imported_refs(t.clone());
 764                                                 }
 765                                         }
 766                                 }
 767                                 if let Some((_, newpath)) = self.imports.get(single_ident_generic_path_to_ident(&p.path).unwrap()) {
 768                                         p.path = newpath.clone();
 769                                 }
 770                                 p.path.segments[0].arguments = args;
 771                         },
 772                         syn::Type::Reference(r) => {
 773                                 r.elem = Box::new(self.resolve_imported_refs((*r.elem).clone()));
 774                         },
 775                         syn::Type::Slice(s) => {
 776                                 s.elem = Box::new(self.resolve_imported_refs((*s.elem).clone()));
 777                         },
 778                         syn::Type::Tuple(t) => {
 779                                 for e in t.elems.iter_mut() {
 780                                         *e = self.resolve_imported_refs(e.clone());
 781                                 }
 782                         },
 783                         _ => unimplemented!(),
 784                 }
 785                 ty
 786         }
 787 }
 788
 789 // templates_defined is walked to write the C++ header, so if we use the default hashing it get
 790 // reordered on each genbindings run. Instead, we use SipHasher (which defaults to 0-keys) so that
 791 // the sorting is stable across runs. It is deprecated, but the "replacement" doesn't actually
 792 // accomplish the same goals, so we just ignore it.
 793 #[allow(deprecated)]
 794 pub type NonRandomHash = hash::BuildHasherDefault<hash::SipHasher>;
 795
 796 /// A public module
 797 pub struct ASTModule {
 798         pub attrs: Vec<syn::Attribute>,
 799         pub items: Vec<syn::Item>,
 800         pub submods: Vec<String>,
 801 }
 802 /// A struct containing the syn::File AST for each file in the crate.
 803 pub struct FullLibraryAST {
 804         pub modules: HashMap<String, ASTModule, NonRandomHash>,
 805         pub dependencies: HashSet<syn::Ident>,
 806 }
 807 impl FullLibraryAST {
 808         fn load_module(&mut self, module: String, attrs: Vec<syn::Attribute>, mut items: Vec<syn::Item>) {
 809                 let mut non_mod_items = Vec::with_capacity(items.len());
 810                 let mut submods = Vec::with_capacity(items.len());
 811                 for item in items.drain(..) {
 812                         match item {
 813                                 syn::Item::Mod(m) if m.content.is_some() => {
 814                                         if export_status(&m.attrs) == ExportStatus::Export {
 815                                                 if let syn::Visibility::Public(_) = m.vis {
 816                                                         let modident = format!("{}", m.ident);
 817                                                         let modname = if module != "" {
 818                                                                 module.clone() + "::" + &modident
 819                                                         } else {
 820                                                                 self.dependencies.insert(m.ident);
 821                                                                 modident.clone()
 822                                                         };
 823                                                         self.load_module(modname, m.attrs, m.content.unwrap().1);
 824                                                         submods.push(modident);
 825                                                 } else {
 826                                                         non_mod_items.push(syn::Item::Mod(m));
 827                                                 }
 828                                         }
 829                                 },
 830                                 syn::Item::Mod(_) => panic!("--pretty=expanded output should never have non-body modules"),
 831                                 syn::Item::ExternCrate(c) => {
 832                                         if export_status(&c.attrs) == ExportStatus::Export {
 833                                                 self.dependencies.insert(c.ident);
 834                                         }
 835                                 },
 836                                 _ => { non_mod_items.push(item); }
 837                         }
 838                 }
 839                 self.modules.insert(module, ASTModule { attrs, items: non_mod_items, submods });
 840         }
 841
 842         pub fn load_lib(lib: syn::File) -> Self {
 843                 assert_eq!(export_status(&lib.attrs), ExportStatus::Export);
 844                 let mut res = Self { modules: HashMap::default(), dependencies: HashSet::new() };
 845                 res.load_module("".to_owned(), lib.attrs, lib.items);
 846                 res
 847         }
 848 }
 849
 850 /// List of manually-generated types which are clonable
 851 fn initial_clonable_types() -> HashSet<String> {
 852         let mut res = HashSet::new();
 853         res.insert("crate::c_types::U5".to_owned());
 854         res.insert("crate::c_types::U128".to_owned());
 855         res.insert("crate::c_types::FourBytes".to_owned());
 856         res.insert("crate::c_types::TwelveBytes".to_owned());
 857         res.insert("crate::c_types::SixteenBytes".to_owned());
 858         res.insert("crate::c_types::TwentyBytes".to_owned());
 859         res.insert("crate::c_types::ThirtyTwoBytes".to_owned());
 860         res.insert("crate::c_types::EightU16s".to_owned());
 861         res.insert("crate::c_types::SecretKey".to_owned());
 862         res.insert("crate::c_types::PublicKey".to_owned());
 863         res.insert("crate::c_types::Transaction".to_owned());
 864         res.insert("crate::c_types::Witness".to_owned());
 865         res.insert("crate::c_types::WitnessVersion".to_owned());
 866         res.insert("crate::c_types::WitnessProgram".to_owned());
 867         res.insert("crate::c_types::TxIn".to_owned());
 868         res.insert("crate::c_types::TxOut".to_owned());
 869         res.insert("crate::c_types::ECDSASignature".to_owned());
 870         res.insert("crate::c_types::SchnorrSignature".to_owned());
 871         res.insert("crate::c_types::RecoverableSignature".to_owned());
 872         res.insert("crate::c_types::BigEndianScalar".to_owned());
 873         res.insert("crate::c_types::Bech32Error".to_owned());
 874         res.insert("crate::c_types::Secp256k1Error".to_owned());
 875         res.insert("crate::c_types::IOError".to_owned());
 876         res.insert("crate::c_types::Error".to_owned());
 877         res.insert("crate::c_types::Str".to_owned());
 878
 879         // Because some types are manually-mapped to CVec_u8Z we may end up checking if its clonable
 880         // before we ever get to constructing the type fully via
 881         // `write_c_mangled_container_path_intern` (which will add it here too), so we have to manually
 882         // add it on startup.
 883         res.insert("crate::c_types::derived::CVec_u8Z".to_owned());
 884         res
 885 }
 886
 887 /// Top-level struct tracking everything which has been defined while walking the crate.
 888 pub struct CrateTypes<'a> {
 889         /// This may contain structs or enums, but only when either is mapped as
 890         /// struct X { inner: *mut originalX, .. }
 891         pub opaques: HashMap<String, (&'a syn::Ident, &'a syn::Generics)>,
 892         /// structs that weren't exposed
 893         pub priv_structs: HashMap<String, &'a syn::Generics>,
 894         /// Enums which are mapped as C enums with conversion functions
 895         pub mirrored_enums: HashMap<String, &'a syn::ItemEnum>,
 896         /// Traits which are mapped as a pointer + jump table
 897         pub traits: HashMap<String, &'a syn::ItemTrait>,
 898         /// Aliases from paths to some other Type
 899         pub type_aliases: HashMap<String, syn::Type>,
 900         /// Value is an alias to Key (maybe with some generics)
 901         pub reverse_alias_map: HashMap<String, Vec<(String, syn::PathArguments)>>,
 902         /// Template continer types defined, map from mangled type name -> whether a destructor fn
 903         /// exists.
 904         ///
 905         /// This is used at the end of processing to make C++ wrapper classes
 906         pub templates_defined: RefCell<HashMap<String, bool, NonRandomHash>>,
 907         /// The output file for any created template container types, written to as we find new
 908         /// template containers which need to be defined.
 909         template_file: RefCell<&'a mut File>,
 910         /// Set of containers which are clonable
 911         clonable_types: RefCell<HashSet<String>>,
 912         /// Key impls Value
 913         pub trait_impls: HashMap<String, Vec<String>>,
 914         /// Value impls Key
 915         pub traits_impld: HashMap<String, Vec<String>>,
 916         /// The full set of modules in the crate(s)
 917         pub lib_ast: &'a FullLibraryAST,
 918 }
 919
 920 impl<'a> CrateTypes<'a> {
 921         pub fn new(template_file: &'a mut File, libast: &'a FullLibraryAST) -> Self {
 922                 CrateTypes {
 923                         opaques: HashMap::new(), mirrored_enums: HashMap::new(), traits: HashMap::new(),
 924                         type_aliases: HashMap::new(), reverse_alias_map: HashMap::new(),
 925                         templates_defined: RefCell::new(HashMap::default()), priv_structs: HashMap::new(),
 926                         clonable_types: RefCell::new(initial_clonable_types()),
 927                         trait_impls: HashMap::new(), traits_impld: HashMap::new(),
 928                         template_file: RefCell::new(template_file), lib_ast: &libast,
 929                 }
 930         }
 931         pub fn set_clonable(&self, object: String) {
 932                 self.clonable_types.borrow_mut().insert(object);
 933         }
 934         pub fn is_clonable(&self, object: &str) -> bool {
 935                 self.clonable_types.borrow().contains(object)
 936         }
 937         pub fn write_new_template(&self, mangled_container: String, has_destructor: bool, created_container: &[u8]) {
 938                 self.template_file.borrow_mut().write(created_container).unwrap();
 939                 self.templates_defined.borrow_mut().insert(mangled_container, has_destructor);
 940         }
 941 }
 942
 943 /// A struct which tracks resolving rust types into C-mapped equivalents, exists for one specific
 944 /// module but contains a reference to the overall CrateTypes tracking.
 945 pub struct TypeResolver<'mod_lifetime, 'crate_lft: 'mod_lifetime> {
 946         pub module_path: &'mod_lifetime str,
 947         pub crate_types: &'mod_lifetime CrateTypes<'crate_lft>,
 948         pub types: ImportResolver<'mod_lifetime, 'crate_lft>,
 949 }
 950
 951 /// Returned by write_empty_rust_val_check_suffix to indicate what type of dereferencing needs to
 952 /// happen to get the inner value of a generic.
 953 enum EmptyValExpectedTy {
 954         /// A type which has a flag for being empty (eg an array where we treat all-0s as empty).
 955         NonPointer,
 956         /// A Option mapped as a COption_*Z
 957         OptionType,
 958         /// A pointer which we want to convert to a reference.
 959         ReferenceAsPointer,
 960 }
 961
 962 #[derive(PartialEq)]
 963 /// Describes the appropriate place to print a general type-conversion string when converting a
 964 /// container.
 965 enum ContainerPrefixLocation {
 966         /// Prints a general type-conversion string prefix and suffix outside of the
 967         /// container-conversion strings.
 968         OutsideConv,
 969         /// Prints a general type-conversion string prefix and suffix inside of the
 970         /// container-conversion strings.
 971         PerConv,
 972         /// Does not print the usual type-conversion string prefix and suffix.
 973         NoPrefix,
 974 }
 975
 976 impl<'a, 'c: 'a> TypeResolver<'a, 'c> {
 977         pub fn new(module_path: &'a str, types: ImportResolver<'a, 'c>, crate_types: &'a CrateTypes<'c>) -> Self {
 978                 Self { module_path, types, crate_types }
 979         }
 980
 981         // *************************************************
 982         // *** Well know type and conversion definitions ***
 983         // *************************************************
 984
 985         /// Returns true we if can just skip passing this to C entirely
 986         pub fn skip_path(&self, full_path: &str) -> bool {
 987                 full_path == "bitcoin::secp256k1::Secp256k1" ||
 988                 full_path == "bitcoin::secp256k1::Signing" ||
 989                 full_path == "bitcoin::secp256k1::Verification"
 990         }
 991         /// Returns true we if can just skip passing this to C entirely
 992         fn no_arg_path_to_rust(&self, full_path: &str) -> &str {
 993                 if full_path == "bitcoin::secp256k1::Secp256k1" {
 994                         "secp256k1::global::SECP256K1"
 995                 } else { unimplemented!(); }
 996         }
 997
 998         /// Returns true if the object is a primitive and is mapped as-is with no conversion
 999         /// whatsoever.
1000         pub fn is_primitive(&self, full_path: &str) -> bool {
1001                 match full_path {
1002                         "bool" => true,
1003                         "i64" => true,
1004                         "f64" => true,
1005                         "u64" => true,
1006                         "u32" => true,
1007                         "u16" => true,
1008                         "u8" => true,
1009                         "usize" => true,
1010                         _ => false,
1011                 }
1012         }
1013         pub fn is_clonable(&self, ty: &str) -> bool {
1014                 if self.crate_types.is_clonable(ty) { return true; }
1015                 if self.is_primitive(ty) { return true; }
1016                 match ty {
1017                         "()" => true,
1018                         _ => false,
1019                 }
1020         }
1021         /// Gets the C-mapped type for types which are outside of the crate, or which are manually
1022         /// ignored by for some reason need mapping anyway.
1023         fn c_type_from_path<'b>(&self, full_path: &'b str, is_ref: bool, _ptr_for_ref: bool) -> Option<&'b str> {
1024                 if self.is_primitive(full_path) {
1025                         return Some(full_path);
1026                 }
1027                 match full_path {
1028                         // Note that no !is_ref types can map to an array because Rust and C's call semantics
1029                         // for arrays are different (https://github.com/eqrion/cbindgen/issues/528)
1030
1031                         "[u8; 32]" if !is_ref => Some("crate::c_types::ThirtyTwoBytes"),
1032                         "[u8; 20]" if !is_ref => Some("crate::c_types::TwentyBytes"),
1033                         "[u8; 16]" if !is_ref => Some("crate::c_types::SixteenBytes"),
1034                         "[u8; 12]" if !is_ref => Some("crate::c_types::TwelveBytes"),
1035                         "[u8; 4]" if !is_ref => Some("crate::c_types::FourBytes"),
1036                         "[u8; 3]" if !is_ref => Some("crate::c_types::ThreeBytes"), // Used for RGB values
1037                         "[u16; 32]" if !is_ref => Some("crate::c_types::ThirtyTwoU16s"),
1038
1039                         "str" if is_ref => Some("crate::c_types::Str"),
1040                         "alloc::string::String"|"String"|"std::path::PathBuf" => Some("crate::c_types::Str"),
1041
1042                         "bitcoin::Address" => Some("crate::c_types::Str"),
1043
1044                         "std::time::Duration"|"core::time::Duration" => Some("u64"),
1045                         "std::time::SystemTime" => Some("u64"),
1046                         "std::io::Error"|"lightning::io::Error"|"lightning::io::ErrorKind" => Some("crate::c_types::IOError"),
1047                         "core::fmt::Arguments" if is_ref => Some("crate::c_types::Str"),
1048
1049                         "core::convert::Infallible" => Some("crate::c_types::NotConstructable"),
1050
1051                         "bitcoin::bech32::Error"|"bech32::Error"
1052                                 if !is_ref => Some("crate::c_types::Bech32Error"),
1053                         "bitcoin::secp256k1::Error"|"secp256k1::Error"
1054                                 if !is_ref => Some("crate::c_types::Secp256k1Error"),
1055
1056                         "core::num::ParseIntError" => Some("crate::c_types::Error"),
1057                         "core::str::Utf8Error" => Some("crate::c_types::Error"),
1058
1059                         "bitcoin::bech32::u5"|"bech32::u5" => Some("crate::c_types::U5"),
1060                         "u128" => Some("crate::c_types::U128"),
1061                         "core::num::NonZeroU8" => Some("u8"),
1062
1063                         "secp256k1::PublicKey"|"bitcoin::secp256k1::PublicKey" => Some("crate::c_types::PublicKey"),
1064                         "bitcoin::secp256k1::ecdsa::Signature" => Some("crate::c_types::ECDSASignature"),
1065                         "bitcoin::secp256k1::schnorr::Signature" => Some("crate::c_types::SchnorrSignature"),
1066                         "bitcoin::secp256k1::ecdsa::RecoverableSignature" => Some("crate::c_types::RecoverableSignature"),
1067                         "bitcoin::secp256k1::SecretKey" if is_ref  => Some("*const [u8; 32]"),
1068                         "bitcoin::secp256k1::SecretKey" if !is_ref => Some("crate::c_types::SecretKey"),
1069                         "bitcoin::secp256k1::KeyPair" if !is_ref => Some("crate::c_types::SecretKey"),
1070                         "bitcoin::secp256k1::Scalar" if is_ref  => Some("*const crate::c_types::BigEndianScalar"),
1071                         "bitcoin::secp256k1::Scalar" if !is_ref => Some("crate::c_types::BigEndianScalar"),
1072                         "bitcoin::secp256k1::ecdh::SharedSecret" if !is_ref => Some("crate::c_types::ThirtyTwoBytes"),
1073
1074                         "bitcoin::blockdata::script::Script"|"bitcoin::Script" => Some("crate::c_types::u8slice"),
1075                         "bitcoin::blockdata::script::ScriptBuf"|"bitcoin::ScriptBuf" => Some("crate::c_types::derived::CVec_u8Z"),
1076                         "bitcoin::OutPoint"|"bitcoin::blockdata::transaction::OutPoint" => Some("crate::lightning::chain::transaction::OutPoint"),
1077                         "bitcoin::blockdata::transaction::Transaction"|"bitcoin::Transaction" => Some("crate::c_types::Transaction"),
1078                         "bitcoin::Witness" => Some("crate::c_types::Witness"),
1079                         "bitcoin::TxIn"|"bitcoin::blockdata::transaction::TxIn" if !is_ref => Some("crate::c_types::TxIn"),
1080                         "bitcoin::TxOut"|"bitcoin::blockdata::transaction::TxOut" => Some("crate::c_types::TxOut"),
1081                         "bitcoin::network::constants::Network" => Some("crate::bitcoin::network::Network"),
1082                         "bitcoin::address::WitnessVersion" => Some("crate::c_types::WitnessVersion"),
1083                         "bitcoin::address::WitnessProgram" => Some("crate::c_types::WitnessProgram"),
1084                         "bitcoin::blockdata::block::Header" if is_ref  => Some("*const [u8; 80]"),
1085                         "bitcoin::blockdata::block::Block" if is_ref  => Some("crate::c_types::u8slice"),
1086
1087                         "bitcoin::blockdata::locktime::absolute::LockTime" => Some("u32"),
1088
1089                         "bitcoin::psbt::PartiallySignedTransaction" if !is_ref => Some("crate::c_types::derived::CVec_u8Z"),
1090
1091                         "bitcoin::PubkeyHash"|"bitcoin::hash_types::PubkeyHash"|
1092                         "bitcoin::hash_types::WPubkeyHash"|
1093                         "bitcoin::ScriptHash"|"bitcoin::hash_types::ScriptHash"
1094                                 if !is_ref => Some("crate::c_types::TwentyBytes"),
1095                         "bitcoin::PubkeyHash"|"bitcoin::hash_types::PubkeyHash"|
1096                         "bitcoin::hash_types::WPubkeyHash"|
1097                         "bitcoin::ScriptHash"|"bitcoin::hash_types::ScriptHash"
1098                                 if is_ref => Some("*const [u8; 20]"),
1099                         "bitcoin::hash_types::WScriptHash"
1100                                 if is_ref => Some("*const [u8; 32]"),
1101
1102                         // Newtypes that we just expose in their original form.
1103                         "bitcoin::hash_types::Txid"|"bitcoin::BlockHash"|"bitcoin::hash_types::BlockHash"|"bitcoin::hashes::sha256::Hash"|"bitcoin::blockdata::constants::ChainHash"
1104                                 if is_ref  => Some("*const [u8; 32]"),
1105                         "bitcoin::hash_types::Txid"|"bitcoin::BlockHash"|"bitcoin::hash_types::BlockHash"|"bitcoin::hashes::sha256::Hash"|"bitcoin::blockdata::constants::ChainHash"
1106                                 if !is_ref => Some("crate::c_types::ThirtyTwoBytes"),
1107                         "bitcoin::secp256k1::Message" if !is_ref => Some("crate::c_types::ThirtyTwoBytes"),
1108                         "bitcoin::secp256k1::Message" if is_ref => Some("*const [u8; 32]"),
1109                         "lightning::ln::PaymentHash"|"lightning::ln::PaymentPreimage"|"lightning::ln::PaymentSecret"
1110                         |"lightning::ln::channelmanager::PaymentId"|"lightning::ln::channelmanager::InterceptId"
1111                         |"lightning::sign::KeyMaterial"|"lightning::chain::ClaimId"
1112                         |"lightning::ln::ChannelId"|"lightning::ln::channel_id::ChannelId"
1113                                 if is_ref => Some("*const [u8; 32]"),
1114                         "lightning::ln::PaymentHash"|"lightning::ln::PaymentPreimage"|"lightning::ln::PaymentSecret"
1115                         |"lightning::ln::channelmanager::PaymentId"|"lightning::ln::channelmanager::InterceptId"
1116                         |"lightning::sign::KeyMaterial"|"lightning::chain::ClaimId"
1117                         |"lightning::ln::ChannelId"|"lightning::ln::channel_id::ChannelId"
1118                                 if !is_ref => Some("crate::c_types::ThirtyTwoBytes"),
1119
1120                         "lightning::io::Read" => Some("crate::c_types::u8slice"),
1121
1122                         _ => None,
1123                 }
1124         }
1125
1126         fn from_c_conversion_new_var_from_path<'b>(&self, _full_path: &str, _is_ref: bool) -> Option<(&'b str, &'b str)> {
1127                 None
1128         }
1129         fn from_c_conversion_prefix_from_path<'b>(&self, full_path: &str, is_ref: bool) -> Option<String> {
1130                 if self.is_primitive(full_path) {
1131                         return Some("".to_owned());
1132                 }
1133                 match full_path {
1134                         "Vec" if !is_ref => Some("local_"),
1135                         "Result" if !is_ref => Some("local_"),
1136                         "Option" if is_ref => Some("&local_"),
1137                         "Option" => Some("local_"),
1138
1139                         "[u8; 32]" if is_ref => Some("unsafe { &*"),
1140                         "[u8; 32]" if !is_ref => Some(""),
1141                         "[u8; 20]" if !is_ref => Some(""),
1142                         "[u8; 16]" if !is_ref => Some(""),
1143                         "[u8; 12]" if !is_ref => Some(""),
1144                         "[u8; 4]" if !is_ref => Some(""),
1145                         "[u8; 3]" if !is_ref => Some(""),
1146                         "[u16; 32]" if !is_ref => Some(""),
1147
1148                         "[u8]" if is_ref => Some(""),
1149                         "[usize]" if is_ref => Some(""),
1150
1151                         "str" if is_ref => Some(""),
1152                         "alloc::string::String"|"String"|"std::path::PathBuf" => Some(""),
1153                         "std::io::Error"|"lightning::io::Error"|"lightning::io::ErrorKind" => Some(""),
1154                         // Note that we'll panic for String if is_ref, as we only have non-owned memory, we
1155                         // cannot create a &String.
1156
1157                         "core::convert::Infallible" => Some("panic!(\"You must never construct a NotConstructable! : "),
1158
1159                         "bitcoin::bech32::Error"|"bech32::Error" if !is_ref => Some(""),
1160                         "bitcoin::secp256k1::Error"|"secp256k1::Error" if !is_ref => Some(""),
1161
1162                         "core::num::ParseIntError" => Some("u8::from_str_radix(\" a\", 10).unwrap_err() /*"),
1163                         "core::str::Utf8Error" => Some("core::str::from_utf8(&[0xff]).unwrap_err() /*"),
1164
1165                         "std::time::Duration"|"core::time::Duration" => Some("core::time::Duration::from_secs("),
1166                         "std::time::SystemTime" => Some("(::std::time::SystemTime::UNIX_EPOCH + std::time::Duration::from_secs("),
1167
1168                         "bitcoin::bech32::u5"|"bech32::u5" => Some(""),
1169                         "u128" => Some(""),
1170                         "core::num::NonZeroU8" => Some("core::num::NonZeroU8::new("),
1171
1172                         "bitcoin::secp256k1::PublicKey"|"secp256k1::PublicKey" if is_ref => Some("&"),
1173                         "bitcoin::secp256k1::PublicKey"|"secp256k1::PublicKey" => Some(""),
1174                         "bitcoin::secp256k1::ecdsa::Signature"|"bitcoin::secp256k1::schnorr::Signature" if is_ref => Some("&"),
1175                         "bitcoin::secp256k1::ecdsa::Signature"|"bitcoin::secp256k1::schnorr::Signature" => Some(""),
1176                         "bitcoin::secp256k1::ecdsa::RecoverableSignature" => Some(""),
1177                         "bitcoin::secp256k1::SecretKey" if is_ref => Some("&::bitcoin::secp256k1::SecretKey::from_slice(&unsafe { *"),
1178                         "bitcoin::secp256k1::SecretKey" if !is_ref => Some(""),
1179                         "bitcoin::secp256k1::KeyPair" if !is_ref => Some("::bitcoin::secp256k1::KeyPair::from_secret_key(&secp256k1::global::SECP256K1, &"),
1180                         "bitcoin::secp256k1::Scalar" if is_ref => Some("&"),
1181                         "bitcoin::secp256k1::Scalar" if !is_ref => Some(""),
1182                         "bitcoin::secp256k1::ecdh::SharedSecret" if !is_ref => Some("::bitcoin::secp256k1::ecdh::SharedSecret::from_bytes("),
1183
1184                         "bitcoin::blockdata::script::Script"|"bitcoin::Script" => Some("::bitcoin::blockdata::script::Script::from_bytes("),
1185                         "bitcoin::blockdata::script::ScriptBuf"|"bitcoin::ScriptBuf" => Some("::bitcoin::blockdata::script::ScriptBuf::from("),
1186                         "bitcoin::blockdata::transaction::Transaction"|"bitcoin::Transaction" if is_ref => Some("&"),
1187                         "bitcoin::blockdata::transaction::Transaction"|"bitcoin::Transaction" => Some(""),
1188                         "bitcoin::Witness" if is_ref => Some("&"),
1189                         "bitcoin::Witness" => Some(""),
1190                         "bitcoin::OutPoint"|"bitcoin::blockdata::transaction::OutPoint" => Some("crate::c_types::C_to_bitcoin_outpoint("),
1191                         "bitcoin::TxIn"|"bitcoin::blockdata::transaction::TxIn" if !is_ref => Some(""),
1192                         "bitcoin::TxOut"|"bitcoin::blockdata::transaction::TxOut" if !is_ref => Some(""),
1193                         "bitcoin::network::constants::Network" => Some(""),
1194                         "bitcoin::address::WitnessVersion" => Some(""),
1195                         "bitcoin::address::WitnessProgram" if is_ref => Some("&"),
1196                         "bitcoin::address::WitnessProgram" if !is_ref => Some(""),
1197                         "bitcoin::blockdata::block::Header" => Some("&::bitcoin::consensus::encode::deserialize(unsafe { &*"),
1198                         "bitcoin::blockdata::block::Block" if is_ref => Some("&::bitcoin::consensus::encode::deserialize("),
1199
1200                         "bitcoin::blockdata::locktime::absolute::LockTime" => Some("::bitcoin::blockdata::locktime::absolute::LockTime::from_consensus("),
1201
1202                         "bitcoin::psbt::PartiallySignedTransaction" if !is_ref => Some("::bitcoin::psbt::PartiallySignedTransaction::deserialize("),
1203
1204                         "bitcoin::PubkeyHash"|"bitcoin::hash_types::PubkeyHash" if !is_ref =>
1205                                 Some("bitcoin::hash_types::PubkeyHash::from_raw_hash(bitcoin::hashes::Hash::from_byte_array("),
1206                         "bitcoin::PubkeyHash"|"bitcoin::hash_types::PubkeyHash" if is_ref =>
1207                                 Some("&bitcoin::hash_types::PubkeyHash::from_raw_hash(bitcoin::hashes::Hash::from_byte_array(unsafe { *"),
1208                         "bitcoin::hash_types::WPubkeyHash" if is_ref =>
1209                                 Some("&bitcoin::hash_types::WPubkeyHash::from_raw_hash(bitcoin::hashes::Hash::from_byte_array(unsafe { *"),
1210                         "bitcoin::ScriptHash"|"bitcoin::hash_types::ScriptHash" if !is_ref =>
1211                                 Some("bitcoin::hash_types::ScriptHash::from_raw_hash(bitcoin::hashes::Hash::from_byte_array("),
1212                         "bitcoin::ScriptHash"|"bitcoin::hash_types::ScriptHash" if is_ref =>
1213                                 Some("&bitcoin::hash_types::ScriptHash::from_raw_hash(bitcoin::hashes::Hash::from_byte_array(unsafe { *"),
1214                         "bitcoin::hash_types::WScriptHash" if is_ref =>
1215                                 Some("&bitcoin::hash_types::WScriptHash::from_raw_hash(bitcoin::hashes::Hash::from_byte_array(unsafe { *"),
1216
1217                         // Newtypes that we just expose in their original form.
1218                         "bitcoin::hash_types::Txid" if is_ref => Some("&::bitcoin::hash_types::Txid::from_slice(&unsafe { &*"),
1219                         "bitcoin::hash_types::Txid" if !is_ref => Some("::bitcoin::hash_types::Txid::from_slice(&"),
1220                         "bitcoin::hash_types::BlockHash"|"bitcoin::BlockHash" => Some("::bitcoin::hash_types::BlockHash::from_slice(&"),
1221                         "bitcoin::blockdata::constants::ChainHash" => Some("::bitcoin::blockdata::constants::ChainHash::from(&"),
1222                         "lightning::ln::PaymentHash" if !is_ref => Some("::lightning::ln::PaymentHash("),
1223                         "lightning::ln::PaymentHash" if is_ref => Some("&::lightning::ln::PaymentHash(unsafe { *"),
1224                         "lightning::ln::PaymentPreimage" if !is_ref => Some("::lightning::ln::PaymentPreimage("),
1225                         "lightning::ln::PaymentPreimage" if is_ref => Some("&::lightning::ln::PaymentPreimage(unsafe { *"),
1226                         "lightning::ln::PaymentSecret" if !is_ref => Some("::lightning::ln::PaymentSecret("),
1227                         "lightning::ln::channelmanager::PaymentId" if !is_ref => Some("::lightning::ln::channelmanager::PaymentId("),
1228                         "lightning::ln::channelmanager::PaymentId" if is_ref=> Some("&::lightning::ln::channelmanager::PaymentId( unsafe { *"),
1229                         "lightning::ln::channelmanager::InterceptId" if !is_ref => Some("::lightning::ln::channelmanager::InterceptId("),
1230                         "lightning::ln::channelmanager::InterceptId" if is_ref=> Some("&::lightning::ln::channelmanager::InterceptId( unsafe { *"),
1231                         "lightning::ln::ChannelId"|"lightning::ln::channel_id::ChannelId" if !is_ref => Some("::lightning::ln::ChannelId("),
1232                         "lightning::ln::ChannelId"|"lightning::ln::channel_id::ChannelId" if is_ref => Some("&::lightning::ln::ChannelId(unsafe { *"),
1233                         "lightning::sign::KeyMaterial" if !is_ref => Some("::lightning::sign::KeyMaterial("),
1234                         "lightning::sign::KeyMaterial" if is_ref=> Some("&::lightning::sign::KeyMaterial( unsafe { *"),
1235                         "lightning::chain::ClaimId" if !is_ref => Some("::lightning::chain::ClaimId("),
1236                         "lightning::chain::ClaimId" if is_ref=> Some("&::lightning::chain::ClaimId( unsafe { *"),
1237
1238                         // List of traits we map (possibly during processing of other files):
1239                         "lightning::io::Read" => Some("&mut "),
1240
1241                         _ => None,
1242                 }.map(|s| s.to_owned())
1243         }
1244         fn from_c_conversion_suffix_from_path<'b>(&self, full_path: &str, is_ref: bool) -> Option<String> {
1245                 if self.is_primitive(full_path) {
1246                         return Some("".to_owned());
1247                 }
1248                 match full_path {
1249                         "Vec" if !is_ref => Some(""),
1250                         "Option" => Some(""),
1251                         "Result" if !is_ref => Some(""),
1252
1253                         "[u8; 32]" if is_ref => Some("}"),
1254                         "[u8; 32]" if !is_ref => Some(".data"),
1255                         "[u8; 20]" if !is_ref => Some(".data"),
1256                         "[u8; 16]" if !is_ref => Some(".data"),
1257                         "[u8; 12]" if !is_ref => Some(".data"),
1258                         "[u8; 4]" if !is_ref => Some(".data"),
1259                         "[u8; 3]" if !is_ref => Some(".data"),
1260                         "[u16; 32]" if !is_ref => Some(".data"),
1261
1262                         "[u8]" if is_ref => Some(".to_slice()"),
1263                         "[usize]" if is_ref => Some(".to_slice()"),
1264
1265                         "str" if is_ref => Some(".into_str()"),
1266                         "alloc::string::String"|"String" => Some(".into_string()"),
1267                         "std::path::PathBuf" => Some(".into_pathbuf()"),
1268                         "std::io::Error"|"lightning::io::Error" => Some(".to_rust()"),
1269                         "lightning::io::ErrorKind" => Some(".to_rust_kind()"),
1270
1271                         "core::convert::Infallible" => Some("\")"),
1272
1273                         "bitcoin::bech32::Error"|"bech32::Error" if !is_ref => Some(".into_rust()"),
1274                         "bitcoin::secp256k1::Error"|"secp256k1::Error" if !is_ref => Some(".into_rust()"),
1275
1276                         "core::num::ParseIntError" => Some("*/"),
1277                         "core::str::Utf8Error" => Some("*/"),
1278
1279                         "std::time::Duration"|"core::time::Duration" => Some(")"),
1280                         "std::time::SystemTime" => Some("))"),
1281
1282                         "bitcoin::bech32::u5"|"bech32::u5" => Some(".into()"),
1283                         "u128" => Some(".into()"),
1284                         "core::num::NonZeroU8" => Some(").expect(\"Value must be non-zero\")"),
1285
1286                         "bitcoin::secp256k1::PublicKey"|"secp256k1::PublicKey" => Some(".into_rust()"),
1287                         "bitcoin::secp256k1::ecdsa::Signature"|"bitcoin::secp256k1::schnorr::Signature" => Some(".into_rust()"),
1288                         "bitcoin::secp256k1::ecdsa::RecoverableSignature" => Some(".into_rust()"),
1289                         "bitcoin::secp256k1::SecretKey" if !is_ref => Some(".into_rust()"),
1290                         "bitcoin::secp256k1::SecretKey" if is_ref => Some("}[..]).unwrap()"),
1291                         "bitcoin::secp256k1::KeyPair" if !is_ref => Some(".into_rust())"),
1292                         "bitcoin::secp256k1::Scalar" => Some(".into_rust()"),
1293                         "bitcoin::secp256k1::ecdh::SharedSecret" if !is_ref => Some(".data)"),
1294
1295                         "bitcoin::blockdata::script::Script"|"bitcoin::Script" => Some(".to_slice())"),
1296                         "bitcoin::blockdata::script::ScriptBuf"|"bitcoin::ScriptBuf" => Some(".into_rust())"),
1297                         "bitcoin::blockdata::transaction::Transaction"|"bitcoin::Transaction" => Some(".into_bitcoin()"),
1298                         "bitcoin::Witness" => Some(".into_bitcoin()"),
1299                         "bitcoin::OutPoint"|"bitcoin::blockdata::transaction::OutPoint" => Some(")"),
1300                         "bitcoin::TxIn"|"bitcoin::blockdata::transaction::TxIn" if !is_ref => Some(".into_rust()"),
1301                         "bitcoin::TxOut"|"bitcoin::blockdata::transaction::TxOut" if !is_ref => Some(".into_rust()"),
1302                         "bitcoin::network::constants::Network" => Some(".into_bitcoin()"),
1303                         "bitcoin::address::WitnessVersion" => Some(".into()"),
1304                         "bitcoin::address::WitnessProgram" => Some(".into_bitcoin()"),
1305                         "bitcoin::blockdata::block::Header" => Some(" }).unwrap()"),
1306                         "bitcoin::blockdata::block::Block" => Some(".to_slice()).unwrap()"),
1307
1308                         "bitcoin::blockdata::locktime::absolute::LockTime" => Some(")"),
1309
1310                         "bitcoin::psbt::PartiallySignedTransaction" if !is_ref => Some(".as_slice()).expect(\"Invalid PSBT format\")"),
1311
1312                         "bitcoin::PubkeyHash"|"bitcoin::hash_types::PubkeyHash"|
1313                         "bitcoin::hash_types::WPubkeyHash"|"bitcoin::hash_types::WScriptHash"|
1314                         "bitcoin::ScriptHash"|"bitcoin::hash_types::ScriptHash"
1315                                 if !is_ref => Some(".data))"),
1316                         "bitcoin::PubkeyHash"|"bitcoin::hash_types::PubkeyHash"|
1317                         "bitcoin::hash_types::WPubkeyHash"|"bitcoin::hash_types::WScriptHash"|
1318                         "bitcoin::ScriptHash"|"bitcoin::hash_types::ScriptHash"
1319                                 if is_ref => Some(" }.clone()))"),
1320
1321                         // Newtypes that we just expose in their original form.
1322                         "bitcoin::hash_types::Txid" if is_ref => Some(" }[..]).unwrap()"),
1323                         "bitcoin::hash_types::Txid" => Some(".data[..]).unwrap()"),
1324                         "bitcoin::hash_types::BlockHash"|"bitcoin::BlockHash" if !is_ref => Some(".data[..]).unwrap()"),
1325                         "bitcoin::blockdata::constants::ChainHash" if !is_ref => Some(".data)"),
1326                         "lightning::ln::PaymentHash"|"lightning::ln::PaymentPreimage"|"lightning::ln::PaymentSecret"
1327                         |"lightning::ln::channelmanager::PaymentId"|"lightning::ln::channelmanager::InterceptId"
1328                         |"lightning::sign::KeyMaterial"|"lightning::chain::ClaimId"
1329                         |"lightning::ln::ChannelId"|"lightning::ln::channel_id::ChannelId"
1330                                 if !is_ref => Some(".data)"),
1331                         "lightning::ln::PaymentHash"|"lightning::ln::PaymentPreimage"|"lightning::ln::PaymentSecret"
1332                         |"lightning::ln::channelmanager::PaymentId"|"lightning::ln::channelmanager::InterceptId"
1333                         |"lightning::sign::KeyMaterial"|"lightning::chain::ClaimId"
1334                         |"lightning::ln::ChannelId"|"lightning::ln::channel_id::ChannelId"
1335                                 if is_ref => Some(" })"),
1336
1337                         // List of traits we map (possibly during processing of other files):
1338                         "lightning::io::Read" => Some(".to_reader()"),
1339
1340                         _ => None,
1341                 }.map(|s| s.to_owned())
1342         }
1343
1344         fn to_c_conversion_new_var_from_path<'b>(&self, full_path: &str, is_ref: bool) -> Option<(&'b str, &'b str)> {
1345                 if self.is_primitive(full_path) {
1346                         return None;
1347                 }
1348                 match full_path {
1349                         "[u8]" if is_ref => Some(("crate::c_types::u8slice::from_slice(", ")")),
1350                         "[usize]" if is_ref => Some(("crate::c_types::usizeslice::from_slice(", ")")),
1351
1352                         "bitcoin::blockdata::block::Header" if is_ref => Some(("{ let mut s = [0u8; 80]; s[..].copy_from_slice(&::bitcoin::consensus::encode::serialize(", ")); s }")),
1353                         "bitcoin::blockdata::block::Block" if is_ref => Some(("::bitcoin::consensus::encode::serialize(", ")")),
1354
1355                         _ => None,
1356                 }.map(|s| s.to_owned())
1357         }
1358         fn to_c_conversion_inline_prefix_from_path(&self, full_path: &str, is_ref: bool, _ptr_for_ref: bool) -> Option<String> {
1359                 if self.is_primitive(full_path) {
1360                         return Some("".to_owned());
1361                 }
1362                 match full_path {
1363                         "Result" if !is_ref => Some("local_"),
1364                         "Vec" if !is_ref => Some("local_"),
1365                         "Option" => Some("local_"),
1366
1367                         "[u8; 32]" if !is_ref => Some("crate::c_types::ThirtyTwoBytes { data: "),
1368                         "[u8; 32]" if is_ref => Some(""),
1369                         "[u8; 20]" if !is_ref => Some("crate::c_types::TwentyBytes { data: "),
1370                         "[u8; 16]" if !is_ref => Some("crate::c_types::SixteenBytes { data: "),
1371                         "[u8; 12]" if !is_ref => Some("crate::c_types::TwelveBytes { data: "),
1372                         "[u8; 4]" if !is_ref => Some("crate::c_types::FourBytes { data: "),
1373                         "[u8; 3]" if is_ref => Some(""),
1374                         "[u16; 32]" if !is_ref => Some("crate::c_types::ThirtyTwoU16s { data: "),
1375
1376                         "[u8]" if is_ref => Some("local_"),
1377                         "[usize]" if is_ref => Some("local_"),
1378
1379                         "str" if is_ref => Some(""),
1380                         "alloc::string::String"|"String"|"std::path::PathBuf" => Some(""),
1381
1382                         "bitcoin::Address" => Some("alloc::string::ToString::to_string(&"),
1383
1384                         "std::time::Duration"|"core::time::Duration" => Some(""),
1385                         "std::time::SystemTime" => Some(""),
1386                         "std::io::Error"|"lightning::io::Error" => Some("crate::c_types::IOError::from_rust("),
1387                         "lightning::io::ErrorKind" => Some("crate::c_types::IOError::from_rust_kind("),
1388                         "core::fmt::Arguments" => Some("alloc::format!(\"{}\", "),
1389
1390                         "core::convert::Infallible" => Some("panic!(\"Cannot construct an Infallible: "),
1391
1392                         "bitcoin::bech32::Error"|"bech32::Error"
1393                                 if !is_ref => Some("crate::c_types::Bech32Error::from_rust("),
1394                         "bitcoin::secp256k1::Error"|"secp256k1::Error"
1395                                 if !is_ref => Some("crate::c_types::Secp256k1Error::from_rust("),
1396
1397                         "core::num::ParseIntError" => Some("crate::c_types::Error { _dummy: 0 } /*"),
1398                         "core::str::Utf8Error" => Some("crate::c_types::Error { _dummy: 0 } /*"),
1399
1400                         "bitcoin::bech32::u5"|"bech32::u5" => Some(""),
1401                         "u128" => Some(""),
1402
1403                         "bitcoin::secp256k1::PublicKey"|"secp256k1::PublicKey" => Some("crate::c_types::PublicKey::from_rust(&"),
1404                         "bitcoin::secp256k1::ecdsa::Signature" => Some("crate::c_types::ECDSASignature::from_rust(&"),
1405                         "bitcoin::secp256k1::schnorr::Signature" => Some("crate::c_types::SchnorrSignature::from_rust(&"),
1406                         "bitcoin::secp256k1::ecdsa::RecoverableSignature" => Some("crate::c_types::RecoverableSignature::from_rust(&"),
1407                         "bitcoin::secp256k1::SecretKey" if is_ref => Some(""),
1408                         "bitcoin::secp256k1::SecretKey" if !is_ref => Some("crate::c_types::SecretKey::from_rust("),
1409                         "bitcoin::secp256k1::KeyPair" if !is_ref => Some("crate::c_types::SecretKey::from_rust("),
1410                         "bitcoin::secp256k1::Scalar" if !is_ref => Some("crate::c_types::BigEndianScalar::from_rust(&"),
1411                         "bitcoin::secp256k1::ecdh::SharedSecret" if !is_ref => Some("crate::c_types::ThirtyTwoBytes { data: "),
1412
1413                         "bitcoin::blockdata::script::Script"|"bitcoin::Script" => Some("crate::c_types::u8slice::from_slice("),
1414                         "bitcoin::blockdata::script::ScriptBuf"|"bitcoin::ScriptBuf" => Some(""),
1415                         "bitcoin::blockdata::transaction::Transaction"|"bitcoin::Transaction" if is_ref => Some("crate::c_types::Transaction::from_bitcoin("),
1416                         "bitcoin::blockdata::transaction::Transaction"|"bitcoin::Transaction" => Some("crate::c_types::Transaction::from_bitcoin(&"),
1417                         "bitcoin::Witness" if is_ref => Some("crate::c_types::Witness::from_bitcoin("),
1418                         "bitcoin::Witness" if !is_ref => Some("crate::c_types::Witness::from_bitcoin(&"),
1419                         "bitcoin::OutPoint"|"bitcoin::blockdata::transaction::OutPoint" if is_ref => Some("crate::c_types::bitcoin_to_C_outpoint("),
1420                         "bitcoin::OutPoint"|"bitcoin::blockdata::transaction::OutPoint" if !is_ref => Some("crate::c_types::bitcoin_to_C_outpoint(&"),
1421                         "bitcoin::TxIn"|"bitcoin::blockdata::transaction::TxIn" if !is_ref => Some("crate::c_types::TxIn::from_rust(&"),
1422                         "bitcoin::TxOut"|"bitcoin::blockdata::transaction::TxOut" if !is_ref => Some("crate::c_types::TxOut::from_rust(&"),
1423                         "bitcoin::TxOut"|"bitcoin::blockdata::transaction::TxOut" if is_ref => Some("crate::c_types::TxOut::from_rust("),
1424                         "bitcoin::network::constants::Network" => Some("crate::bitcoin::network::Network::from_bitcoin("),
1425                         "bitcoin::address::WitnessVersion" => Some(""),
1426                         "bitcoin::address::WitnessProgram" => Some("crate::c_types::WitnessProgram::from_bitcoin("),
1427                         "bitcoin::blockdata::block::Header" if is_ref => Some("&local_"),
1428                         "bitcoin::blockdata::block::Block" if is_ref => Some("crate::c_types::u8slice::from_slice(&local_"),
1429
1430                         "bitcoin::blockdata::locktime::absolute::LockTime" => Some(""),
1431
1432                         "bitcoin::psbt::PartiallySignedTransaction" if !is_ref => Some(""),
1433
1434                         "bitcoin::PubkeyHash"|"bitcoin::hash_types::PubkeyHash"|
1435                         "bitcoin::hash_types::WPubkeyHash"|"bitcoin::hash_types::WScriptHash"|
1436                         "bitcoin::ScriptHash"|"bitcoin::hash_types::ScriptHash"
1437                                 if !is_ref => Some("crate::c_types::TwentyBytes { data: *"),
1438
1439                         // Newtypes that we just expose in their original form.
1440                         "bitcoin::hash_types::Txid"|"bitcoin::BlockHash"|"bitcoin::hash_types::BlockHash"|"bitcoin::hashes::sha256::Hash"|"bitcoin::blockdata::constants::ChainHash"
1441                                 if is_ref => Some(""),
1442                         "bitcoin::hash_types::Txid"|"bitcoin::BlockHash"|"bitcoin::hash_types::BlockHash"|"bitcoin::hashes::sha256::Hash"|"bitcoin::blockdata::constants::ChainHash"
1443                                 if !is_ref => Some("crate::c_types::ThirtyTwoBytes { data: *"),
1444                         "bitcoin::secp256k1::Message" if !is_ref => Some("crate::c_types::ThirtyTwoBytes { data: "),
1445                         "bitcoin::secp256k1::Message" if is_ref => Some(""),
1446                         "lightning::ln::PaymentHash"|"lightning::ln::PaymentPreimage"|"lightning::ln::PaymentSecret"
1447                         |"lightning::ln::channelmanager::PaymentId"|"lightning::ln::channelmanager::InterceptId"
1448                         |"lightning::sign::KeyMaterial"|"lightning::chain::ClaimId"
1449                         |"lightning::ln::ChannelId"|"lightning::ln::channel_id::ChannelId"
1450                                 if is_ref => Some("&"),
1451                         "lightning::ln::PaymentHash"|"lightning::ln::PaymentPreimage"|"lightning::ln::PaymentSecret"
1452                         |"lightning::ln::channelmanager::PaymentId"|"lightning::ln::channelmanager::InterceptId"
1453                         |"lightning::sign::KeyMaterial"|"lightning::chain::ClaimId"
1454                         |"lightning::ln::ChannelId"|"lightning::ln::channel_id::ChannelId"
1455                                 if !is_ref => Some("crate::c_types::ThirtyTwoBytes { data: "),
1456
1457                         "lightning::io::Read" => Some("crate::c_types::u8slice::from_vec(&crate::c_types::reader_to_vec("),
1458
1459                         _ => None,
1460                 }.map(|s| s.to_owned())
1461         }
1462         fn to_c_conversion_inline_suffix_from_path(&self, full_path: &str, is_ref: bool, _ptr_for_ref: bool) -> Option<String> {
1463                 if self.is_primitive(full_path) {
1464                         return Some("".to_owned());
1465                 }
1466                 match full_path {
1467                         "Result" if !is_ref => Some(""),
1468                         "Vec" if !is_ref => Some(".into()"),
1469                         "Option" => Some(""),
1470
1471                         "[u8; 32]" if !is_ref => Some(" }"),
1472                         "[u8; 32]" if is_ref => Some(""),
1473                         "[u8; 20]" if !is_ref => Some(" }"),
1474                         "[u8; 16]" if !is_ref => Some(" }"),
1475                         "[u8; 12]" if !is_ref => Some(" }"),
1476                         "[u8; 4]" if !is_ref => Some(" }"),
1477                         "[u8; 3]" if is_ref => Some(""),
1478                         "[u16; 32]" if !is_ref => Some(" }"),
1479
1480                         "[u8]" if is_ref => Some(""),
1481                         "[usize]" if is_ref => Some(""),
1482
1483                         "str" if is_ref => Some(".into()"),
1484                         "alloc::string::String"|"String"|"std::path::PathBuf" if is_ref => Some(".as_str().into()"),
1485                         "alloc::string::String"|"String"|"std::path::PathBuf" => Some(".into()"),
1486
1487                         "bitcoin::Address" => Some(").into()"),
1488
1489                         "std::time::Duration"|"core::time::Duration" => Some(".as_secs()"),
1490                         "std::time::SystemTime" => Some(".duration_since(::std::time::SystemTime::UNIX_EPOCH).expect(\"Times must be post-1970\").as_secs()"),
1491                         "std::io::Error"|"lightning::io::Error"|"lightning::io::ErrorKind" => Some(")"),
1492                         "core::fmt::Arguments" => Some(").into()"),
1493
1494                         "core::convert::Infallible" => Some("\")"),
1495
1496                         "bitcoin::secp256k1::Error"|"bech32::Error"
1497                                 if !is_ref => Some(")"),
1498                         "bitcoin::secp256k1::Error"|"secp256k1::Error"
1499                                 if !is_ref => Some(")"),
1500
1501                         "core::num::ParseIntError" => Some("*/"),
1502                         "core::str::Utf8Error" => Some("*/"),
1503
1504                         "bitcoin::bech32::u5"|"bech32::u5" => Some(".into()"),
1505                         "u128" => Some(".into()"),
1506
1507                         "bitcoin::secp256k1::PublicKey"|"secp256k1::PublicKey" => Some(")"),
1508                         "bitcoin::secp256k1::ecdsa::Signature"|"bitcoin::secp256k1::schnorr::Signature" => Some(")"),
1509                         "bitcoin::secp256k1::ecdsa::RecoverableSignature" => Some(")"),
1510                         "bitcoin::secp256k1::SecretKey" if !is_ref => Some(")"),
1511                         "bitcoin::secp256k1::SecretKey" if is_ref => Some(".as_ref()"),
1512                         "bitcoin::secp256k1::KeyPair" if !is_ref => Some(".secret_key())"),
1513                         "bitcoin::secp256k1::Scalar" if !is_ref => Some(")"),
1514                         "bitcoin::secp256k1::ecdh::SharedSecret" if !is_ref => Some(".secret_bytes() }"),
1515
1516                         "bitcoin::blockdata::script::Script"|"bitcoin::Script" => Some(".as_ref())"),
1517                         "bitcoin::blockdata::script::ScriptBuf"|"bitcoin::ScriptBuf" if is_ref => Some(".as_bytes().to_vec().into()"),
1518                         "bitcoin::blockdata::script::ScriptBuf"|"bitcoin::ScriptBuf" if !is_ref => Some(".to_bytes().into()"),
1519                         "bitcoin::blockdata::transaction::Transaction"|"bitcoin::Transaction" => Some(")"),
1520                         "bitcoin::Witness" => Some(")"),
1521                         "bitcoin::OutPoint"|"bitcoin::blockdata::transaction::OutPoint" => Some(")"),
1522                         "bitcoin::TxIn"|"bitcoin::blockdata::transaction::TxIn" if !is_ref => Some(")"),
1523                         "bitcoin::TxOut"|"bitcoin::blockdata::transaction::TxOut" => Some(")"),
1524                         "bitcoin::network::constants::Network" => Some(")"),
1525                         "bitcoin::address::WitnessVersion" => Some(".into()"),
1526                         "bitcoin::address::WitnessProgram" => Some(")"),
1527                         "bitcoin::blockdata::block::Header" if is_ref => Some(""),
1528                         "bitcoin::blockdata::block::Block" if is_ref => Some(")"),
1529
1530                         "bitcoin::blockdata::locktime::absolute::LockTime" => Some(".to_consensus_u32()"),
1531
1532                         "bitcoin::psbt::PartiallySignedTransaction" if !is_ref => Some(".serialize().into()"),
1533
1534                         "bitcoin::PubkeyHash"|"bitcoin::hash_types::PubkeyHash"|
1535                         "bitcoin::hash_types::WPubkeyHash"|"bitcoin::hash_types::WScriptHash"|
1536                         "bitcoin::ScriptHash"|"bitcoin::hash_types::ScriptHash"
1537                                 if !is_ref => Some(".as_ref() }"),
1538
1539                         // Newtypes that we just expose in their original form.
1540                         "bitcoin::hash_types::Txid"|"bitcoin::BlockHash"|"bitcoin::hash_types::BlockHash"|"bitcoin::hashes::sha256::Hash"|"bitcoin::blockdata::constants::ChainHash"
1541                                 if is_ref => Some(".as_ref()"),
1542                         "bitcoin::hash_types::Txid"|"bitcoin::BlockHash"|"bitcoin::hash_types::BlockHash"|"bitcoin::hashes::sha256::Hash"|"bitcoin::blockdata::constants::ChainHash"
1543                                 if !is_ref => Some(".as_ref() }"),
1544                         "bitcoin::secp256k1::Message" if !is_ref => Some(".as_ref().clone() }"),
1545                         "bitcoin::secp256k1::Message" if is_ref => Some(".as_ref()"),
1546                         "lightning::ln::PaymentHash"|"lightning::ln::PaymentPreimage"|"lightning::ln::PaymentSecret"
1547                         |"lightning::ln::channelmanager::PaymentId"|"lightning::ln::channelmanager::InterceptId"
1548                         |"lightning::sign::KeyMaterial"|"lightning::chain::ClaimId"
1549                         |"lightning::ln::ChannelId"|"lightning::ln::channel_id::ChannelId"
1550                                 if is_ref => Some(".0"),
1551                         "lightning::ln::PaymentHash"|"lightning::ln::PaymentPreimage"|"lightning::ln::PaymentSecret"
1552                         |"lightning::ln::channelmanager::PaymentId"|"lightning::ln::channelmanager::InterceptId"
1553                         |"lightning::sign::KeyMaterial"|"lightning::chain::ClaimId"
1554                         |"lightning::ln::ChannelId"|"lightning::ln::channel_id::ChannelId"
1555                                 if !is_ref => Some(".0 }"),
1556
1557                         "lightning::io::Read" => Some("))"),
1558
1559                         _ => None,
1560                 }.map(|s| s.to_owned())
1561         }
1562
1563         fn empty_val_check_suffix_from_path(&self, full_path: &str) -> Option<&str> {
1564                 match full_path {
1565                         "secp256k1::PublicKey"|"bitcoin::secp256k1::PublicKey" => Some(".is_null()"),
1566                         _ => None
1567                 }
1568         }
1569
1570         /// When printing a reference to the source crate's rust type, if we need to map it to a
1571         /// different "real" type, it can be done so here.
1572         /// This is useful to work around limitations in the binding type resolver, where we reference
1573         /// a non-public `use` alias.
1574         /// TODO: We should never need to use this!
1575         fn real_rust_type_mapping<'equiv>(&self, thing: &'equiv str) -> &'equiv str {
1576                 match thing {
1577                         "lightning::io::Read" => "crate::c_types::io::Read",
1578                         _ => thing,
1579                 }
1580         }
1581
1582         // ****************************
1583         // *** Container Processing ***
1584         // ****************************
1585
1586         /// Returns the module path in the generated mapping crate to the containers which we generate
1587         /// when writing to CrateTypes::template_file.
1588         pub fn generated_container_path() -> &'static str {
1589                 "crate::c_types::derived"
1590         }
1591         /// Returns the module path in the generated mapping crate to the container templates, which
1592         /// are then concretized and put in the generated container path/template_file.
1593         fn container_templ_path() -> &'static str {
1594                 "crate::c_types"
1595         }
1596
1597         /// This should just be a closure, but doing so gets an error like
1598         /// error: reached the recursion limit while instantiating `types::TypeResolver::is_transpar...c/types.rs:1358:104: 1358:110]>>`
1599         /// which implies the concrete function instantiation of `is_transparent_container` ends up
1600         /// being recursive.
1601         fn deref_type<'one, 'b: 'one> (obj: &'one &'b syn::Type) -> &'b syn::Type { *obj }
1602
1603         /// Returns true if the path containing the given args is a "transparent" container, ie an
1604         /// Option or a container which does not require a generated continer class.
1605         fn is_transparent_container<'i, I: Iterator<Item=&'i syn::Type>>(&self, full_path: &str, _is_ref: bool, mut args: I, generics: Option<&GenericTypes>) -> bool {
1606                 if full_path == "Option" {
1607                         let inner = args.next().unwrap();
1608                         assert!(args.next().is_none());
1609                         match generics.resolve_type(inner) {
1610                                 syn::Type::Reference(r) => {
1611                                         let elem = &*r.elem;
1612                                         match elem {
1613                                                 syn::Type::Path(_) =>
1614                                                         self.is_transparent_container(full_path, true, [elem].iter().map(Self::deref_type), generics),
1615                                                 _ => true,
1616                                         }
1617                                 },
1618                                 syn::Type::Array(a) => {
1619                                         if let syn::Expr::Lit(l) = &a.len {
1620                                                 if let syn::Lit::Int(i) = &l.lit {
1621                                                         if i.base10_digits().parse::<usize>().unwrap() >= 32 {
1622                                                                 let mut buf = Vec::new();
1623                                                                 self.write_rust_type(&mut buf, generics, &a.elem, false);
1624                                                                 let ty = String::from_utf8(buf).unwrap();
1625                                                                 ty == "u8"
1626                                                         } else {
1627                                                                 // Blindly assume that if we're trying to create an empty value for an
1628                                                                 // array < 32 entries that all-0s may be a valid state.
1629                                                                 unimplemented!();
1630                                                         }
1631                                                 } else { unimplemented!(); }
1632                                         } else { unimplemented!(); }
1633                                 },
1634                                 syn::Type::Path(p) => {
1635                                         if let Some(resolved) = self.maybe_resolve_path(&p.path, generics) {
1636                                                 if self.c_type_has_inner_from_path(&resolved) { return true; }
1637                                                 if self.is_primitive(&resolved) { return false; }
1638                                                 // We want to move to using `Option_` mappings where possible rather than
1639                                                 // manual mappings, as it makes downstream bindings simpler and is more
1640                                                 // clear for users. Thus, we default to false but override for a few
1641                                                 // types which had mappings defined when we were avoiding the `Option_`s.
1642                                                 match &resolved as &str {
1643                                                         "secp256k1::PublicKey"|"bitcoin::secp256k1::PublicKey" => true,
1644                                                         _ => false,
1645                                                 }
1646                                         } else { unimplemented!(); }
1647                                 },
1648                                 syn::Type::Tuple(_) => false,
1649                                 _ => unimplemented!(),
1650                         }
1651                 } else { false }
1652         }
1653         /// Returns true if the path is a "transparent" container, ie an Option or a container which does
1654         /// not require a generated continer class.
1655         pub fn is_path_transparent_container(&self, full_path: &syn::Path, generics: Option<&GenericTypes>, is_ref: bool) -> bool {
1656                 let inner_iter = match &full_path.segments.last().unwrap().arguments {
1657                         syn::PathArguments::None => return false,
1658                         syn::PathArguments::AngleBracketed(args) => args.args.iter().map(|arg| {
1659                                 if let syn::GenericArgument::Type(ref ty) = arg {
1660                                         ty
1661                                 } else { unimplemented!() }
1662                         }),
1663                         syn::PathArguments::Parenthesized(_) => unimplemented!(),
1664                 };
1665                 self.is_transparent_container(&self.resolve_path(full_path, generics), is_ref, inner_iter, generics)
1666         }
1667         /// Returns true if this is a known, supported, non-transparent container.
1668         fn is_known_container(&self, full_path: &str, is_ref: bool) -> bool {
1669                 (full_path == "Result" && !is_ref) || (full_path == "Vec" && !is_ref) || full_path.ends_with("Tuple") || full_path == "Option"
1670         }
1671         fn to_c_conversion_container_new_var<'b>(&self, generics: Option<&GenericTypes>, full_path: &str, is_ref: bool, single_contained: Option<&syn::Type>, var_name: &syn::Ident, var_access: &str)
1672                         // Returns prefix + Vec<(prefix, var-name-to-inline-convert)> + suffix
1673                         // expecting one element in the vec per generic type, each of which is inline-converted
1674                         -> Option<(&'b str, Vec<(String, String)>, &'b str, ContainerPrefixLocation)> {
1675                 match full_path {
1676                         "Result" if !is_ref => {
1677                                 Some(("match ",
1678                                                 vec![(" { Ok(mut o) => crate::c_types::CResultTempl::ok(".to_string(), "o".to_string()),
1679                                                         (").into(), Err(mut e) => crate::c_types::CResultTempl::err(".to_string(), "e".to_string())],
1680                                                 ").into() }", ContainerPrefixLocation::PerConv))
1681                         },
1682                         "Vec" => {
1683                                 if is_ref {
1684                                         // We should only get here if the single contained has an inner
1685                                         assert!(self.c_type_has_inner(single_contained.unwrap()));
1686                                 }
1687                                 Some(("Vec::new(); for mut item in ", vec![(format!(".drain(..) {{ local_{}.push(", var_name), "item".to_string())], "); }", ContainerPrefixLocation::PerConv))
1688                         },
1689                         "Slice" => {
1690                                 if let Some(syn::Type::Reference(_)) = single_contained {
1691                                         Some(("Vec::new(); for item in ", vec![(format!(".iter() {{ local_{}.push(", var_name), "(*item)".to_string())], "); }", ContainerPrefixLocation::PerConv))
1692                                 } else {
1693                                         Some(("Vec::new(); for item in ", vec![(format!(".iter() {{ local_{}.push(", var_name), "item".to_string())], "); }", ContainerPrefixLocation::PerConv))
1694                                 }
1695                         },
1696                         "Option" => {
1697                                 let mut is_contained_ref = false;
1698                                 let contained_struct = if let Some(syn::Type::Path(p)) = single_contained {
1699                                         Some(self.resolve_path(&p.path, generics))
1700                                 } else if let Some(syn::Type::Reference(r)) = single_contained {
1701                                         is_contained_ref = true;
1702                                         if let syn::Type::Path(p) = &*r.elem {
1703                                                 Some(self.resolve_path(&p.path, generics))
1704                                         } else { None }
1705                                 } else { None };
1706                                 if let Some(inner_path) = contained_struct {
1707                                         let only_contained_has_inner = self.c_type_has_inner_from_path(&inner_path);
1708                                         if self.c_type_has_inner_from_path(&inner_path) {
1709                                                 let is_inner_ref = if let Some(syn::Type::Reference(_)) = single_contained { true } else { false };
1710                                                 if is_ref {
1711                                                         return Some(("if ", vec![
1712                                                                 (".is_none() { core::ptr::null() } else { ObjOps::nonnull_ptr_to_inner(".to_owned(),
1713                                                                         format!("({}{}.unwrap())", var_access, if is_inner_ref { "" } else { ".as_ref()" }))
1714                                                                 ], ") }", ContainerPrefixLocation::OutsideConv));
1715                                                 } else {
1716                                                         return Some(("if ", vec![
1717                                                                 (".is_none() { core::ptr::null_mut() } else { ".to_owned(), format!("({}.unwrap())", var_access))
1718                                                                 ], " }", ContainerPrefixLocation::OutsideConv));
1719                                                 }
1720                                         } else if !self.is_transparent_container("Option", is_ref, [single_contained.unwrap()].iter().map(|a| *a), generics) {
1721                                                 if self.is_primitive(&inner_path) || (!is_contained_ref && !is_ref) || only_contained_has_inner {
1722                                                         let inner_name = self.get_c_mangled_container_type(vec![single_contained.unwrap()], generics, "Option").unwrap();
1723                                                         return Some(("if ", vec![
1724                                                                 (format!(".is_none() {{ {}::None }} else {{ {}::Some(", inner_name, inner_name),
1725                                                                  format!("{}.unwrap()", var_access))
1726                                                                 ], ") }", ContainerPrefixLocation::PerConv));
1727                                                 } else {
1728                                                         let inner_name = self.get_c_mangled_container_type(vec![single_contained.unwrap()], generics, "Option").unwrap();
1729                                                         return Some(("if ", vec![
1730                                                                 (format!(".is_none() {{ {}::None }} else {{ {}::Some(/* WARNING: CLONING CONVERSION HERE! &Option<Enum> is otherwise un-expressable. */", inner_name, inner_name),
1731                                                                  format!("(*{}.as_ref().unwrap()).clone()", var_access))
1732                                                                 ], ") }", ContainerPrefixLocation::PerConv));
1733                                                 }
1734                                         } else {
1735                                                 // If c_type_from_path is some (ie there's a manual mapping for the inner
1736                                                 // type), lean on write_empty_rust_val, below.
1737                                         }
1738                                 }
1739                                 if let Some(t) = single_contained {
1740                                         if let syn::Type::Tuple(syn::TypeTuple { elems, .. }) = t {
1741                                                 let inner_name = self.get_c_mangled_container_type(vec![single_contained.unwrap()], generics, "Option").unwrap();
1742                                                 if elems.is_empty() {
1743                                                         return Some(("if ", vec![
1744                                                                 (format!(".is_none() {{ {}::None }} else {{ {}::Some /* ",
1745                                                                         inner_name, inner_name), format!(""))
1746                                                                 ], " */ }", ContainerPrefixLocation::PerConv));
1747                                                 } else {
1748                                                         return Some(("if ", vec![
1749                                                                 (format!(".is_none() {{ {}::None }} else {{ {}::Some(",
1750                                                                         inner_name, inner_name), format!("({}.unwrap())", var_access))
1751                                                                 ], ") }", ContainerPrefixLocation::PerConv));
1752                                                 }
1753                                         }
1754                                         if let syn::Type::Reference(syn::TypeReference { elem, .. }) = t {
1755                                                 if let syn::Type::Slice(_) = &**elem {
1756                                                         return Some(("if ", vec![
1757                                                                         (".is_none() { SmartPtr::null() } else { SmartPtr::from_obj(".to_string(),
1758                                                                          format!("({}.unwrap())", var_access))
1759                                                                 ], ") }", ContainerPrefixLocation::PerConv));
1760                                                 }
1761                                         }
1762                                         let mut v = Vec::new();
1763                                         self.write_empty_rust_val(generics, &mut v, t);
1764                                         let s = String::from_utf8(v).unwrap();
1765                                         return Some(("if ", vec![
1766                                                 (format!(".is_none() {{ {} }} else {{ ", s), format!("({}.unwrap())", var_access))
1767                                                 ], " }", ContainerPrefixLocation::PerConv));
1768                                 } else { unreachable!(); }
1769                         },
1770                         _ => None,
1771                 }
1772         }
1773
1774         /// only_contained_has_inner implies that there is only one contained element in the container
1775         /// and it has an inner field (ie is an "opaque" type we've defined).
1776         fn from_c_conversion_container_new_var<'b>(&self, generics: Option<&GenericTypes>, full_path: &str, is_ref: bool, single_contained: Option<&syn::Type>, var_name: &syn::Ident, var_access: &str)
1777                         // Returns prefix + Vec<(prefix, var-name-to-inline-convert)> + suffix
1778                         // expecting one element in the vec per generic type, each of which is inline-converted
1779                         -> Option<(&'b str, Vec<(String, String)>, &'b str, ContainerPrefixLocation)> {
1780                 let mut only_contained_has_inner = false;
1781                 let only_contained_resolved = if let Some(syn::Type::Path(p)) = single_contained {
1782                         let res = self.resolve_path(&p.path, generics);
1783                         only_contained_has_inner = self.c_type_has_inner_from_path(&res);
1784                         Some(res)
1785                 } else { None };
1786                 match full_path {
1787                         "Result" if !is_ref => {
1788                                 Some(("match ",
1789                                                 vec![(".result_ok { true => Ok(".to_string(), format!("(*unsafe {{ Box::from_raw(<*mut _>::take_ptr(&mut {}.contents.result)) }})", var_access)),
1790                                                      ("), false => Err(".to_string(), format!("(*unsafe {{ Box::from_raw(<*mut _>::take_ptr(&mut {}.contents.err)) }})", var_access))],
1791                                                 ")}", ContainerPrefixLocation::PerConv))
1792                         },
1793                         "Slice" if is_ref && only_contained_has_inner => {
1794                                 Some(("Vec::new(); for mut item in ", vec![(format!(".as_slice().iter() {{ local_{}.push(", var_name), "item".to_string())], "); }", ContainerPrefixLocation::PerConv))
1795                         },
1796                         "Vec"|"Slice" => {
1797                                 Some(("Vec::new(); for mut item in ", vec![(format!(".into_rust().drain(..) {{ local_{}.push(", var_name), "item".to_string())], "); }", ContainerPrefixLocation::PerConv))
1798                         },
1799                         "Option" => {
1800                                 if let Some(resolved) = only_contained_resolved {
1801                                         if self.is_primitive(&resolved) {
1802                                                 return Some(("if ", vec![(".is_some() { Some(".to_string(), format!("{}.take()", var_access))], ") } else { None }", ContainerPrefixLocation::NoPrefix))
1803                                         } else if only_contained_has_inner {
1804                                                 if is_ref {
1805                                                         return Some(("if ", vec![(".inner.is_null() { None } else { Some((*".to_string(), format!("{}", var_access))], ").clone()) }", ContainerPrefixLocation::PerConv))
1806                                                 } else {
1807                                                         return Some(("if ", vec![(".inner.is_null() { None } else { Some(".to_string(), format!("{}", var_access))], ") }", ContainerPrefixLocation::PerConv));
1808                                                 }
1809                                         }
1810                                 }
1811
1812                                 if let Some(t) = single_contained {
1813                                         match t {
1814                                                 syn::Type::Reference(_)|syn::Type::Path(_)|syn::Type::Slice(_)|syn::Type::Array(_) => {
1815                                                         let mut v = Vec::new();
1816                                                         let ret_ref = self.write_empty_rust_val_check_suffix(generics, &mut v, t);
1817                                                         let s = String::from_utf8(v).unwrap();
1818                                                         match ret_ref {
1819                                                                 EmptyValExpectedTy::ReferenceAsPointer =>
1820                                                                         return Some(("if ", vec![
1821                                                                                 (format!("{} {{ None }} else {{ Some(", s), format!("unsafe {{ &mut *{} }}", var_access))
1822                                                                         ], ") }", ContainerPrefixLocation::NoPrefix)),
1823                                                                 EmptyValExpectedTy::OptionType =>
1824                                                                         return Some(("{ /*", vec![
1825                                                                                 (format!("*/ let {}_opt = {}; if {}_opt{} {{ None }} else {{ Some({{", var_name, var_access, var_name, s),
1826                                                                                 format!("{{ {}_opt.take() }}", var_name))
1827                                                                         ], "})} }", ContainerPrefixLocation::PerConv)),
1828                                                                 EmptyValExpectedTy::NonPointer =>
1829                                                                         return Some(("if ", vec![
1830                                                                                 (format!("{} {{ None }} else {{ Some(", s), format!("{}", var_access))
1831                                                                         ], ") }", ContainerPrefixLocation::PerConv)),
1832                                                         }
1833                                                 },
1834                                                 syn::Type::Tuple(_) => {
1835                                                         return Some(("if ", vec![(".is_some() { Some(".to_string(), format!("{}.take()", var_access))], ") } else { None }", ContainerPrefixLocation::PerConv))
1836                                                 },
1837                                                 _ => unimplemented!(),
1838                                         }
1839                                 } else { unreachable!(); }
1840                         },
1841                         _ => None,
1842                 }
1843         }
1844
1845         /// Constructs a reference to the given type, possibly tweaking the type if relevant to make it
1846         /// convertable to C.
1847         pub fn create_ownable_reference(&self, t: &syn::Type, generics: Option<&GenericTypes>) -> Option<syn::Type> {
1848                 let default_value = Some(syn::Type::Reference(syn::TypeReference {
1849                         and_token: syn::Token!(&)(Span::call_site()), lifetime: None, mutability: None,
1850                         elem: Box::new(t.clone()) }));
1851                 match generics.resolve_type(t) {
1852                         syn::Type::Path(p) => {
1853                                 if let Some(resolved_path) = self.maybe_resolve_path(&p.path, generics) {
1854                                         if resolved_path != "Vec" { return default_value; }
1855                                         if p.path.segments.len() != 1 { unimplemented!(); }
1856                                         let only_seg = p.path.segments.iter().next().unwrap();
1857                                         if let syn::PathArguments::AngleBracketed(args) = &only_seg.arguments {
1858                                                 if args.args.len() != 1 { unimplemented!(); }
1859                                                 let inner_arg = args.args.iter().next().unwrap();
1860                                                 if let syn::GenericArgument::Type(ty) = &inner_arg {
1861                                                         let mut can_create = self.c_type_has_inner(&ty);
1862                                                         if let syn::Type::Path(inner) = ty {
1863                                                                 if inner.path.segments.len() == 1 &&
1864                                                                                 format!("{}", inner.path.segments[0].ident) == "Vec" {
1865                                                                         can_create = true;
1866                                                                 }
1867                                                         }
1868                                                         if !can_create { return default_value; }
1869                                                         if let Some(inner_ty) = self.create_ownable_reference(&ty, generics) {
1870                                                                 return Some(syn::Type::Reference(syn::TypeReference {
1871                                                                         and_token: syn::Token![&](Span::call_site()),
1872                                                                         lifetime: None,
1873                                                                         mutability: None,
1874                                                                         elem: Box::new(syn::Type::Slice(syn::TypeSlice {
1875                                                                                 bracket_token: syn::token::Bracket { span: Span::call_site() },
1876                                                                                 elem: Box::new(inner_ty)
1877                                                                         }))
1878                                                                 }));
1879                                                         } else { return default_value; }
1880                                                 } else { unimplemented!(); }
1881                                         } else { unimplemented!(); }
1882                                 } else { return None; }
1883                         },
1884                         _ => default_value,
1885                 }
1886         }
1887
1888         // *************************************************
1889         // *** Type definition during main.rs processing ***
1890         // *************************************************
1891
1892         /// Returns true if the object at the given path is mapped as X { inner: *mut origX, .. }.
1893         pub fn c_type_has_inner_from_path(&self, full_path: &str) -> bool {
1894                 self.crate_types.opaques.get(full_path).is_some()
1895         }
1896
1897         /// Returns true if the object at the given path is mapped as X { inner: *mut origX, .. }.
1898         pub fn c_type_has_inner(&self, ty: &syn::Type) -> bool {
1899                 match ty {
1900                         syn::Type::Path(p) => {
1901                                 if let Some(full_path) = self.maybe_resolve_path(&p.path, None) {
1902                                         self.c_type_has_inner_from_path(&full_path)
1903                                 } else { false }
1904                         },
1905                         syn::Type::Reference(r) => {
1906                                 self.c_type_has_inner(&*r.elem)
1907                         },
1908                         _ => false,
1909                 }
1910         }
1911
1912         pub fn maybe_resolve_ident(&self, id: &syn::Ident) -> Option<String> {
1913                 self.types.maybe_resolve_ident(id)
1914         }
1915
1916         pub fn maybe_resolve_path(&self, p_arg: &syn::Path, generics: Option<&GenericTypes>) -> Option<String> {
1917                 self.types.maybe_resolve_path(p_arg, generics)
1918         }
1919         pub fn resolve_path(&self, p: &syn::Path, generics: Option<&GenericTypes>) -> String {
1920                 self.maybe_resolve_path(p, generics).unwrap()
1921         }
1922
1923         // ***********************************
1924         // *** Original Rust Type Printing ***
1925         // ***********************************
1926
1927         fn in_rust_prelude(resolved_path: &str) -> bool {
1928                 match resolved_path {
1929                         "Vec" => true,
1930                         "Result" => true,
1931                         "Option" => true,
1932                         _ => false,
1933                 }
1934         }
1935
1936         fn write_rust_path<W: std::io::Write>(&self, w: &mut W, generics_resolver: Option<&GenericTypes>, path: &syn::Path, with_ref_lifetime: bool, generated_crate_ref: bool) {
1937                 if let Some(resolved) = self.maybe_resolve_path(&path, generics_resolver) {
1938                         if self.is_primitive(&resolved) {
1939                                 write!(w, "{}", path.get_ident().unwrap()).unwrap();
1940                         } else {
1941                                 // TODO: We should have a generic "is from a dependency" check here instead of
1942                                 // checking for "bitcoin" explicitly.
1943                                 if resolved.starts_with("bitcoin::") || Self::in_rust_prelude(&resolved) {
1944                                         write!(w, "{}", resolved).unwrap();
1945                                 } else if !generated_crate_ref {
1946                                         // If we're printing a generic argument, it needs to reference the crate, otherwise
1947                                         // the original crate.
1948                                         write!(w, "{}", self.real_rust_type_mapping(&resolved)).unwrap();
1949                                 } else {
1950                                         write!(w, "crate::{}", resolved).unwrap();
1951                                 }
1952                         }
1953                         if let syn::PathArguments::AngleBracketed(args) = &path.segments.iter().last().unwrap().arguments {
1954                                 self.write_rust_generic_arg(w, generics_resolver, args.args.iter(), with_ref_lifetime);
1955                         }
1956                 } else {
1957                         if path.leading_colon.is_some() {
1958                                 write!(w, "::").unwrap();
1959                         }
1960                         for (idx, seg) in path.segments.iter().enumerate() {
1961                                 if idx != 0 { write!(w, "::").unwrap(); }
1962                                 write!(w, "{}", seg.ident).unwrap();
1963                                 if let syn::PathArguments::AngleBracketed(args) = &seg.arguments {
1964                                         self.write_rust_generic_arg(w, generics_resolver, args.args.iter(), with_ref_lifetime);
1965                                 }
1966                         }
1967                 }
1968         }
1969         pub fn write_rust_generic_param<'b, W: std::io::Write>(&self, w: &mut W, generics_resolver: Option<&GenericTypes>, generics: impl Iterator<Item=&'b syn::GenericParam>) {
1970                 let mut had_params = false;
1971                 for (idx, arg) in generics.enumerate() {
1972                         if idx != 0 { write!(w, ", ").unwrap(); } else { write!(w, "<").unwrap(); }
1973                         had_params = true;
1974                         match arg {
1975                                 syn::GenericParam::Lifetime(lt) => write!(w, "'{}", lt.lifetime.ident).unwrap(),
1976                                 syn::GenericParam::Type(t) => {
1977                                         write!(w, "{}", t.ident).unwrap();
1978                                         if t.colon_token.is_some() { write!(w, ":").unwrap(); }
1979                                         for (idx, bound) in t.bounds.iter().enumerate() {
1980                                                 if idx != 0 { write!(w, " + ").unwrap(); }
1981                                                 match bound {
1982                                                         syn::TypeParamBound::Trait(tb) => {
1983                                                                 if tb.paren_token.is_some() || tb.lifetimes.is_some() { unimplemented!(); }
1984                                                                 self.write_rust_path(w, generics_resolver, &tb.path, false, false);
1985                                                         },
1986                                                         _ => unimplemented!(),
1987                                                 }
1988                                         }
1989                                         if t.eq_token.is_some() || t.default.is_some() { unimplemented!(); }
1990                                 },
1991                                 _ => unimplemented!(),
1992                         }
1993                 }
1994                 if had_params { write!(w, ">").unwrap(); }
1995         }
1996
1997         pub fn write_rust_generic_arg<'b, W: std::io::Write>(&self, w: &mut W, generics_resolver: Option<&GenericTypes>, generics: impl Iterator<Item=&'b syn::GenericArgument>, with_ref_lifetime: bool) {
1998                 write!(w, "<").unwrap();
1999                 for (idx, arg) in generics.enumerate() {
2000                         if idx != 0 { write!(w, ", ").unwrap(); }
2001                         match arg {
2002                                 syn::GenericArgument::Type(t) => self.write_rust_type(w, generics_resolver, t, with_ref_lifetime),
2003                                 _ => unimplemented!(),
2004                         }
2005                 }
2006                 write!(w, ">").unwrap();
2007         }
2008         fn do_write_rust_type<W: std::io::Write>(&self, w: &mut W, generics: Option<&GenericTypes>, t: &syn::Type, with_ref_lifetime: bool, force_crate_ref: bool) {
2009                 let real_ty = generics.resolve_type(t);
2010                 let mut generate_crate_ref = force_crate_ref || t != real_ty;
2011                 match real_ty {
2012                         syn::Type::Path(p) => {
2013                                 if p.qself.is_some() {
2014                                         unimplemented!();
2015                                 }
2016                                 if let Some(resolved_ty) = self.maybe_resolve_path(&p.path, generics) {
2017                                         generate_crate_ref |= self.maybe_resolve_path(&p.path, None).as_ref() != Some(&resolved_ty);
2018                                         if self.crate_types.traits.get(&resolved_ty).is_none() { generate_crate_ref = false; }
2019                                 }
2020                                 self.write_rust_path(w, generics, &p.path, with_ref_lifetime, generate_crate_ref);
2021                         },
2022                         syn::Type::Reference(r) => {
2023                                 write!(w, "&").unwrap();
2024                                 if let Some(lft) = &r.lifetime {
2025                                         write!(w, "'{} ", lft.ident).unwrap();
2026                                 } else if with_ref_lifetime {
2027                                         write!(w, "'static ").unwrap();
2028                                 }
2029                                 if r.mutability.is_some() {
2030                                         write!(w, "mut ").unwrap();
2031                                 }
2032                                 self.do_write_rust_type(w, generics, &*r.elem, with_ref_lifetime, generate_crate_ref);
2033                         },
2034                         syn::Type::Array(a) => {
2035                                 write!(w, "[").unwrap();
2036                                 self.do_write_rust_type(w, generics, &a.elem, with_ref_lifetime, generate_crate_ref);
2037                                 if let syn::Expr::Lit(l) = &a.len {
2038                                         if let syn::Lit::Int(i) = &l.lit {
2039                                                 write!(w, "; {}]", i).unwrap();
2040                                         } else { unimplemented!(); }
2041                                 } else { unimplemented!(); }
2042                         }
2043                         syn::Type::Slice(s) => {
2044                                 write!(w, "[").unwrap();
2045                                 self.do_write_rust_type(w, generics, &s.elem, with_ref_lifetime, generate_crate_ref);
2046                                 write!(w, "]").unwrap();
2047                         },
2048                         syn::Type::Tuple(s) => {
2049                                 write!(w, "(").unwrap();
2050                                 for (idx, t) in s.elems.iter().enumerate() {
2051                                         if idx != 0 { write!(w, ", ").unwrap(); }
2052                                         self.do_write_rust_type(w, generics, &t, with_ref_lifetime, generate_crate_ref);
2053                                 }
2054                                 write!(w, ")").unwrap();
2055                         },
2056                         _ => unimplemented!(),
2057                 }
2058         }
2059         pub fn write_rust_type<W: std::io::Write>(&self, w: &mut W, generics: Option<&GenericTypes>, t: &syn::Type, with_ref_lifetime: bool) {
2060                 self.do_write_rust_type(w, generics, t, with_ref_lifetime, false);
2061         }
2062
2063
2064         /// Prints a constructor for something which is "uninitialized" (but obviously not actually
2065         /// unint'd memory).
2066         pub fn write_empty_rust_val<W: std::io::Write>(&self, generics: Option<&GenericTypes>, w: &mut W, t: &syn::Type) {
2067                 match t {
2068                         syn::Type::Reference(r) => {
2069                                 self.write_empty_rust_val(generics, w, &*r.elem)
2070                         },
2071                         syn::Type::Path(p) => {
2072                                 let resolved = self.resolve_path(&p.path, generics);
2073                                 if self.crate_types.opaques.get(&resolved).is_some() {
2074                                         write!(w, "crate::{} {{ inner: core::ptr::null_mut(), is_owned: true }}", resolved).unwrap();
2075                                 } else {
2076                                         // Assume its a manually-mapped C type, where we can just define an null() fn
2077                                         write!(w, "{}::null()", self.c_type_from_path(&resolved, false, false).unwrap()).unwrap();
2078                                 }
2079                         },
2080                         syn::Type::Array(a) => {
2081                                 if let syn::Expr::Lit(l) = &a.len {
2082                                         if let syn::Lit::Int(i) = &l.lit {
2083                                                 if i.base10_digits().parse::<usize>().unwrap() < 32 {
2084                                                         // Blindly assume that if we're trying to create an empty value for an
2085                                                         // array < 32 entries that all-0s may be a valid state.
2086                                                         unimplemented!();
2087                                                 }
2088                                                 let arrty = format!("[u8; {}]", i.base10_digits());
2089                                                 write!(w, "{}", self.to_c_conversion_inline_prefix_from_path(&arrty, false, false).unwrap()).unwrap();
2090                                                 write!(w, "[0; {}]", i.base10_digits()).unwrap();
2091                                                 write!(w, "{}", self.to_c_conversion_inline_suffix_from_path(&arrty, false, false).unwrap()).unwrap();
2092                                         } else { unimplemented!(); }
2093                                 } else { unimplemented!(); }
2094                         }
2095                         _ => unimplemented!(),
2096                 }
2097         }
2098
2099         /// Prints a suffix to determine if a variable is empty (ie was set by write_empty_rust_val).
2100         /// See EmptyValExpectedTy for information on return types.
2101         fn write_empty_rust_val_check_suffix<W: std::io::Write>(&self, generics: Option<&GenericTypes>, w: &mut W, t: &syn::Type) -> EmptyValExpectedTy {
2102                 match t {
2103                         syn::Type::Reference(r) => {
2104                                 return self.write_empty_rust_val_check_suffix(generics, w, &*r.elem);
2105                         },
2106                         syn::Type::Path(p) => {
2107                                 let resolved = self.resolve_path(&p.path, generics);
2108                                 if self.crate_types.opaques.get(&resolved).is_some() {
2109                                         write!(w, ".inner.is_null()").unwrap();
2110                                         EmptyValExpectedTy::NonPointer
2111                                 } else {
2112                                         if let Some(suffix) = self.empty_val_check_suffix_from_path(&resolved) {
2113                                                 write!(w, "{}", suffix).unwrap();
2114                                                 // We may eventually need to allow empty_val_check_suffix_from_path to specify if we need a deref or not
2115                                                 EmptyValExpectedTy::NonPointer
2116                                         } else {
2117                                                 write!(w, ".is_none()").unwrap();
2118                                                 EmptyValExpectedTy::OptionType
2119                                         }
2120                                 }
2121                         },
2122                         syn::Type::Array(a) => {
2123                                 if let syn::Expr::Lit(l) = &a.len {
2124                                         if let syn::Lit::Int(i) = &l.lit {
2125                                                 write!(w, ".data == [0; {}]", i.base10_digits()).unwrap();
2126                                                 EmptyValExpectedTy::NonPointer
2127                                         } else { unimplemented!(); }
2128                                 } else { unimplemented!(); }
2129                         },
2130                         syn::Type::Slice(_) => {
2131                                 // Option<[]> always implies that we want to treat len() == 0 differently from
2132                                 // None, so we always map an Option<[]> into a pointer.
2133                                 write!(w, " == core::ptr::null_mut()").unwrap();
2134                                 EmptyValExpectedTy::ReferenceAsPointer
2135                         },
2136                         _ => unimplemented!(),
2137                 }
2138         }
2139
2140         /// Prints a suffix to determine if a variable is empty (ie was set by write_empty_rust_val).
2141         pub fn write_empty_rust_val_check<W: std::io::Write>(&self, generics: Option<&GenericTypes>, w: &mut W, t: &syn::Type, var_access: &str) {
2142                 match t {
2143                         syn::Type::Reference(r) => {
2144                                 self.write_empty_rust_val_check(generics, w, &*r.elem, var_access);
2145                         },
2146                         syn::Type::Path(_) => {
2147                                 write!(w, "{}", var_access).unwrap();
2148                                 self.write_empty_rust_val_check_suffix(generics, w, t);
2149                         },
2150                         syn::Type::Array(a) => {
2151                                 if let syn::Expr::Lit(l) = &a.len {
2152                                         if let syn::Lit::Int(i) = &l.lit {
2153                                                 let arrty = format!("[u8; {}]", i.base10_digits());
2154                                                 // We don't (yet) support a new-var conversion here.
2155                                                 assert!(self.from_c_conversion_new_var_from_path(&arrty, false).is_none());
2156                                                 write!(w, "{}{}{}",
2157                                                         self.from_c_conversion_prefix_from_path(&arrty, false).unwrap(),
2158                                                         var_access,
2159                                                         self.from_c_conversion_suffix_from_path(&arrty, false).unwrap()).unwrap();
2160                                                 self.write_empty_rust_val_check_suffix(generics, w, t);
2161                                         } else { unimplemented!(); }
2162                                 } else { unimplemented!(); }
2163                         }
2164                         _ => unimplemented!(),
2165                 }
2166         }
2167
2168         // ********************************
2169         // *** Type conversion printing ***
2170         // ********************************
2171
2172         /// Returns true we if can just skip passing this to C entirely
2173         pub fn skip_arg(&self, t: &syn::Type, generics: Option<&GenericTypes>) -> bool {
2174                 match t {
2175                         syn::Type::Path(p) => {
2176                                 if p.qself.is_some() { unimplemented!(); }
2177                                 if let Some(full_path) = self.maybe_resolve_path(&p.path, generics) {
2178                                         self.skip_path(&full_path)
2179                                 } else { false }
2180                         },
2181                         syn::Type::Reference(r) => {
2182                                 self.skip_arg(&*r.elem, generics)
2183                         },
2184                         _ => false,
2185                 }
2186         }
2187         pub fn no_arg_to_rust<W: std::io::Write>(&self, w: &mut W, t: &syn::Type, generics: Option<&GenericTypes>) {
2188                 match t {
2189                         syn::Type::Path(p) => {
2190                                 if p.qself.is_some() { unimplemented!(); }
2191                                 if let Some(full_path) = self.maybe_resolve_path(&p.path, generics) {
2192                                         write!(w, "{}", self.no_arg_path_to_rust(&full_path)).unwrap();
2193                                 }
2194                         },
2195                         syn::Type::Reference(r) => {
2196                                 self.no_arg_to_rust(w, &*r.elem, generics);
2197                         },
2198                         _ => {},
2199                 }
2200         }
2201
2202         fn write_conversion_inline_intern<W: std::io::Write,
2203                         LP: Fn(&str, bool, bool) -> Option<String>, DL: Fn(&mut W, &DeclType, &str, bool, bool), SC: Fn(bool, Option<&str>) -> String>
2204                         (&self, w: &mut W, t: &syn::Type, generics: Option<&GenericTypes>, is_ref: bool, is_mut: bool, ptr_for_ref: bool,
2205                          tupleconv: &str, prefix: bool, sliceconv: SC, path_lookup: LP, decl_lookup: DL) {
2206                 match generics.resolve_type(t) {
2207                         syn::Type::Reference(r) => {
2208                                 self.write_conversion_inline_intern(w, &*r.elem, generics, true, r.mutability.is_some(),
2209                                         ptr_for_ref, tupleconv, prefix, sliceconv, path_lookup, decl_lookup);
2210                         },
2211                         syn::Type::Path(p) => {
2212                                 if p.qself.is_some() {
2213                                         unimplemented!();
2214                                 }
2215
2216                                 let resolved_path = self.resolve_path(&p.path, generics);
2217                                 if let Some(aliased_type) = self.crate_types.type_aliases.get(&resolved_path) {
2218                                         return self.write_conversion_inline_intern(w, aliased_type, None, is_ref, is_mut, ptr_for_ref, tupleconv, prefix, sliceconv, path_lookup, decl_lookup);
2219                                 } else if self.is_primitive(&resolved_path) {
2220                                         if is_ref && prefix {
2221                                                 write!(w, "*").unwrap();
2222                                         }
2223                                 } else if let Some(c_type) = path_lookup(&resolved_path, is_ref, ptr_for_ref) {
2224                                         write!(w, "{}", c_type).unwrap();
2225                                 } else if let Some((_, generics)) = self.crate_types.opaques.get(&resolved_path) {
2226                                         decl_lookup(w, &DeclType::StructImported { generics: &generics }, &resolved_path, is_ref, is_mut);
2227                                 } else if self.crate_types.mirrored_enums.get(&resolved_path).is_some() {
2228                                         decl_lookup(w, &DeclType::MirroredEnum, &resolved_path, is_ref, is_mut);
2229                                 } else if let Some(t) = self.crate_types.traits.get(&resolved_path) {
2230                                         decl_lookup(w, &DeclType::Trait(t), &resolved_path, is_ref, is_mut);
2231                                 } else if let Some(ident) = single_ident_generic_path_to_ident(&p.path) {
2232                                         if let Some(decl_type) = self.types.maybe_resolve_declared(ident) {
2233                                                 decl_lookup(w, decl_type, &self.maybe_resolve_ident(ident).unwrap(), is_ref, is_mut);
2234                                         } else { unimplemented!(); }
2235                                 } else {
2236                                         if let Some(trait_impls) = self.crate_types.traits_impld.get(&resolved_path) {
2237                                                 if trait_impls.len() == 1 {
2238                                                         // If this is a no-export'd crate and there's only one implementation
2239                                                         // in the whole crate, just treat it as a reference to whatever the
2240                                                         // implementor is.
2241                                                         let implementor = self.crate_types.opaques.get(&trait_impls[0]).unwrap();
2242                                                         decl_lookup(w, &DeclType::StructImported { generics: &implementor.1 }, &trait_impls[0], true, is_mut);
2243                                                         return;
2244                                                 }
2245                                         }
2246                                         unimplemented!();
2247                                 }
2248                         },
2249                         syn::Type::Array(a) => {
2250                                 if let syn::Type::Path(p) = &*a.elem {
2251                                         let inner_ty = self.resolve_path(&p.path, generics);
2252                                         if let syn::Expr::Lit(l) = &a.len {
2253                                                 if let syn::Lit::Int(i) = &l.lit {
2254                                                         write!(w, "{}", path_lookup(&format!("[{}; {}]", inner_ty, i.base10_digits()), is_ref, ptr_for_ref).unwrap()).unwrap();
2255                                                 } else { unimplemented!(); }
2256                                         } else { unimplemented!(); }
2257                                 } else { unimplemented!(); }
2258                         },
2259                         syn::Type::Slice(s) => {
2260                                 // We assume all slices contain only literals or references.
2261                                 // This may result in some outputs not compiling.
2262                                 if let syn::Type::Path(p) = &*s.elem {
2263                                         let resolved = self.resolve_path(&p.path, generics);
2264                                         if self.is_primitive(&resolved) {
2265                                                 write!(w, "{}", path_lookup("[u8]", is_ref, ptr_for_ref).unwrap()).unwrap();
2266                                         } else {
2267                                                 write!(w, "{}", sliceconv(true, None)).unwrap();
2268                                         }
2269                                 } else if let syn::Type::Reference(r) = &*s.elem {
2270                                         if let syn::Type::Path(p) = &*r.elem {
2271                                                 write!(w, "{}", sliceconv(self.c_type_has_inner_from_path(&self.resolve_path(&p.path, generics)), None)).unwrap();
2272                                         } else if let syn::Type::Slice(_) = &*r.elem {
2273                                                 write!(w, "{}", sliceconv(false, None)).unwrap();
2274                                         } else { unimplemented!(); }
2275                                 } else if let syn::Type::Tuple(t) = &*s.elem {
2276                                         assert!(!t.elems.is_empty());
2277                                         if prefix {
2278                                                 write!(w, "{}", sliceconv(false, None)).unwrap();
2279                                         } else {
2280                                                 let mut needs_map = false;
2281                                                 for e in t.elems.iter() {
2282                                                         if let syn::Type::Reference(_) = e {
2283                                                                 needs_map = true;
2284                                                         }
2285                                                 }
2286                                                 if needs_map {
2287                                                         let mut map_str = Vec::new();
2288                                                         write!(&mut map_str, ".map(|(").unwrap();
2289                                                         for i in 0..t.elems.len() {
2290                                                                 write!(&mut map_str, "{}{}", if i != 0 { ", " } else { "" }, ('a' as u8 + i as u8) as char).unwrap();
2291                                                         }
2292                                                         write!(&mut map_str, ")| (").unwrap();
2293                                                         for (idx, e) in t.elems.iter().enumerate() {
2294                                                                 if let syn::Type::Reference(_) = e {
2295                                                                         write!(&mut map_str, "{}{}", if idx != 0 { ", " } else { "" }, (idx as u8 + 'a' as u8) as char).unwrap();
2296                                                                 } else if let syn::Type::Path(_) = e {
2297                                                                         write!(&mut map_str, "{}*{}", if idx != 0 { ", " } else { "" }, (idx as u8 + 'a' as u8) as char).unwrap();
2298                                                                 } else { unimplemented!(); }
2299                                                         }
2300                                                         write!(&mut map_str, "))").unwrap();
2301                                                         write!(w, "{}", sliceconv(false, Some(&String::from_utf8(map_str).unwrap()))).unwrap();
2302                                                 } else {
2303                                                         write!(w, "{}", sliceconv(false, None)).unwrap();
2304                                                 }
2305                                         }
2306                                 } else if let syn::Type::Array(_) = &*s.elem {
2307                                         write!(w, "{}", sliceconv(false, Some(".map(|a| *a)"))).unwrap();
2308                                 } else { unimplemented!(); }
2309                         },
2310                         syn::Type::Tuple(t) => {
2311                                 if t.elems.is_empty() {
2312                                         // cbindgen has poor support for (), see, eg https://github.com/eqrion/cbindgen/issues/527
2313                                         // so work around it by just pretending its a 0u8
2314                                         write!(w, "{}", tupleconv).unwrap();
2315                                 } else {
2316                                         if prefix { write!(w, "local_").unwrap(); }
2317                                 }
2318                         },
2319                         _ => unimplemented!(),
2320                 }
2321         }
2322
2323         fn write_to_c_conversion_inline_prefix_inner<W: std::io::Write>(&self, w: &mut W, t: &syn::Type, generics: Option<&GenericTypes>, is_ref: bool, ptr_for_ref: bool, from_ptr: bool) {
2324                 self.write_conversion_inline_intern(w, t, generics, is_ref, false, ptr_for_ref, "() /*", true, |_, _| "local_".to_owned(),
2325                                 |a, b, c| self.to_c_conversion_inline_prefix_from_path(a, b, c),
2326                                 |w, decl_type, decl_path, is_ref, _is_mut| {
2327                                         match decl_type {
2328                                                 DeclType::MirroredEnum if is_ref && ptr_for_ref => write!(w, "crate::{}::from_native(", decl_path).unwrap(),
2329                                                 DeclType::MirroredEnum if is_ref => write!(w, "&crate::{}::from_native(", decl_path).unwrap(),
2330                                                 DeclType::MirroredEnum => write!(w, "crate::{}::native_into(", decl_path).unwrap(),
2331                                                 DeclType::EnumIgnored {..}|DeclType::StructImported {..} if is_ref && from_ptr => {
2332                                                         if !ptr_for_ref { write!(w, "&").unwrap(); }
2333                                                         write!(w, "crate::{} {{ inner: unsafe {{ (", decl_path).unwrap()
2334                                                 },
2335                                                 DeclType::EnumIgnored {..}|DeclType::StructImported {..} if is_ref => {
2336                                                         if !ptr_for_ref { write!(w, "&").unwrap(); }
2337                                                         write!(w, "crate::{} {{ inner: unsafe {{ ObjOps::nonnull_ptr_to_inner((", decl_path).unwrap()
2338                                                 },
2339                                                 DeclType::EnumIgnored {..}|DeclType::StructImported {..} if !is_ref && from_ptr =>
2340                                                         write!(w, "crate::{} {{ inner: ", decl_path).unwrap(),
2341                                                 DeclType::EnumIgnored {..}|DeclType::StructImported {..} if !is_ref =>
2342                                                         write!(w, "crate::{} {{ inner: ObjOps::heap_alloc(", decl_path).unwrap(),
2343                                                 DeclType::Trait(_) if is_ref => write!(w, "").unwrap(),
2344                                                 DeclType::Trait(_) if !is_ref => write!(w, "Into::into(").unwrap(),
2345                                                 _ => panic!("{:?}", decl_path),
2346                                         }
2347                                 });
2348         }
2349         pub fn write_to_c_conversion_inline_prefix<W: std::io::Write>(&self, w: &mut W, t: &syn::Type, generics: Option<&GenericTypes>, ptr_for_ref: bool) {
2350                 self.write_to_c_conversion_inline_prefix_inner(w, t, generics, false, ptr_for_ref, false);
2351         }
2352         fn write_to_c_conversion_inline_suffix_inner<W: std::io::Write>(&self, w: &mut W, t: &syn::Type, generics: Option<&GenericTypes>, is_ref: bool, ptr_for_ref: bool, from_ptr: bool) {
2353                 self.write_conversion_inline_intern(w, t, generics, is_ref, false, ptr_for_ref, "*/", false, |_, _| ".into()".to_owned(),
2354                                 |a, b, c| self.to_c_conversion_inline_suffix_from_path(a, b, c),
2355                                 |w, decl_type, full_path, is_ref, _is_mut| match decl_type {
2356                                         DeclType::MirroredEnum => write!(w, ")").unwrap(),
2357                                         DeclType::EnumIgnored { generics }|DeclType::StructImported { generics } if is_ref => {
2358                                                 write!(w, " as *const {}<", full_path).unwrap();
2359                                                 for param in generics.params.iter() {
2360                                                         if let syn::GenericParam::Lifetime(_) = param {
2361                                                                 write!(w, "'_, ").unwrap();
2362                                                         } else {
2363                                                                 write!(w, "_, ").unwrap();
2364                                                         }
2365                                                 }
2366                                                 if from_ptr {
2367                                                         write!(w, ">) as *mut _ }}, is_owned: false }}").unwrap();
2368                                                 } else {
2369                                                         write!(w, ">) as *mut _) }}, is_owned: false }}").unwrap();
2370                                                 }
2371                                         },
2372                                         DeclType::EnumIgnored {..}|DeclType::StructImported {..} if !is_ref && from_ptr =>
2373                                                 write!(w, ", is_owned: true }}").unwrap(),
2374                                         DeclType::EnumIgnored {..}|DeclType::StructImported {..} if !is_ref => write!(w, "), is_owned: true }}").unwrap(),
2375                                         DeclType::Trait(_) if is_ref => {},
2376                                         DeclType::Trait(_) => {
2377                                                 // This is used when we're converting a concrete Rust type into a C trait
2378                                                 // for use when a Rust trait method returns an associated type.
2379                                                 // Because all of our C traits implement From<RustTypesImplementingTraits>
2380                                                 // we can just call .into() here and be done.
2381                                                 write!(w, ")").unwrap()
2382                                         },
2383                                         _ => unimplemented!(),
2384                                 });
2385         }
2386         pub fn write_to_c_conversion_inline_suffix<W: std::io::Write>(&self, w: &mut W, t: &syn::Type, generics: Option<&GenericTypes>, ptr_for_ref: bool) {
2387                 self.write_to_c_conversion_inline_suffix_inner(w, t, generics, false, ptr_for_ref, false);
2388         }
2389
2390         fn write_from_c_conversion_prefix_inner<W: std::io::Write>(&self, w: &mut W, t: &syn::Type, generics: Option<&GenericTypes>, is_ref: bool, _ptr_for_ref: bool) {
2391                 self.write_conversion_inline_intern(w, t, generics, is_ref, false, false, "() /*", true, |_, _| "&local_".to_owned(),
2392                                 |a, b, _c| self.from_c_conversion_prefix_from_path(a, b),
2393                                 |w, decl_type, _full_path, is_ref, _is_mut| match decl_type {
2394                                         DeclType::StructImported {..} if is_ref => write!(w, "").unwrap(),
2395                                         DeclType::StructImported {..} if !is_ref => write!(w, "*unsafe {{ Box::from_raw(").unwrap(),
2396                                         DeclType::MirroredEnum if is_ref => write!(w, "&").unwrap(),
2397                                         DeclType::MirroredEnum => {},
2398                                         DeclType::Trait(_) => {},
2399                                         _ => unimplemented!(),
2400                                 });
2401         }
2402         pub fn write_from_c_conversion_prefix<W: std::io::Write>(&self, w: &mut W, t: &syn::Type, generics: Option<&GenericTypes>) {
2403                 self.write_from_c_conversion_prefix_inner(w, t, generics, false, false);
2404         }
2405         fn write_from_c_conversion_suffix_inner<W: std::io::Write>(&self, w: &mut W, t: &syn::Type, generics: Option<&GenericTypes>, is_ref: bool, ptr_for_ref: bool) {
2406                 self.write_conversion_inline_intern(w, t, generics, is_ref, false, false, "*/", false,
2407                                 |has_inner, map_str_opt| match (has_inner, map_str_opt) {
2408                                         (false, Some(map_str)) => format!(".iter(){}.collect::<Vec<_>>()[..]", map_str),
2409                                         (false, None) => ".iter().collect::<Vec<_>>()[..]".to_owned(),
2410                                         (true, None) => "[..]".to_owned(),
2411                                         (true, Some(_)) => unreachable!(),
2412                                 },
2413                                 |a, b, _c| self.from_c_conversion_suffix_from_path(a, b),
2414                                 |w, decl_type, _full_path, is_ref, is_mut| match decl_type {
2415                                         DeclType::StructImported {..} if is_ref && ptr_for_ref => write!(w, "XXX unimplemented").unwrap(),
2416                                         DeclType::StructImported {..} if is_mut && is_ref => write!(w, ".get_native_mut_ref()").unwrap(),
2417                                         DeclType::StructImported {..} if is_ref => write!(w, ".get_native_ref()").unwrap(),
2418                                         DeclType::StructImported {..} if !is_ref => write!(w, ".take_inner()) }}").unwrap(),
2419                                         DeclType::MirroredEnum if is_ref => write!(w, ".to_native()").unwrap(),
2420                                         DeclType::MirroredEnum => write!(w, ".into_native()").unwrap(),
2421                                         DeclType::Trait(_) => {},
2422                                         _ => unimplemented!(),
2423                                 });
2424         }
2425         pub fn write_from_c_conversion_suffix<W: std::io::Write>(&self, w: &mut W, t: &syn::Type, generics: Option<&GenericTypes>) {
2426                 self.write_from_c_conversion_suffix_inner(w, t, generics, false, false);
2427         }
2428         // Note that compared to the above conversion functions, the following two are generally
2429         // significantly undertested:
2430         pub fn write_from_c_conversion_to_ref_prefix<W: std::io::Write>(&self, w: &mut W, t: &syn::Type, generics: Option<&GenericTypes>) {
2431                 self.write_conversion_inline_intern(w, t, generics, false, false, false, "() /*", true, |_, _| "&local_".to_owned(),
2432                                 |a, b, _c| {
2433                                         if let Some(conv) = self.from_c_conversion_prefix_from_path(a, b) {
2434                                                 Some(format!("&{}", conv))
2435                                         } else { None }
2436                                 },
2437                                 |w, decl_type, _full_path, is_ref, _is_mut| match decl_type {
2438                                         DeclType::StructImported {..} if !is_ref => write!(w, "").unwrap(),
2439                                         _ => unimplemented!(),
2440                                 });
2441         }
2442         pub fn write_from_c_conversion_to_ref_suffix<W: std::io::Write>(&self, w: &mut W, t: &syn::Type, generics: Option<&GenericTypes>) {
2443                 self.write_conversion_inline_intern(w, t, generics, false, false, false, "*/", false,
2444                                 |has_inner, map_str_opt| match (has_inner, map_str_opt) {
2445                                         (false, Some(map_str)) => format!(".iter(){}.collect::<Vec<_>>()[..]", map_str),
2446                                         (false, None) => ".iter().collect::<Vec<_>>()[..]".to_owned(),
2447                                         (true, None) => "[..]".to_owned(),
2448                                         (true, Some(_)) => unreachable!(),
2449                                 },
2450                                 |a, b, _c| self.from_c_conversion_suffix_from_path(a, b),
2451                                 |w, decl_type, _full_path, is_ref, _is_mut| match decl_type {
2452                                         DeclType::StructImported {..} if !is_ref => write!(w, ".get_native_ref()").unwrap(),
2453                                         _ => unimplemented!(),
2454                                 });
2455         }
2456
2457         fn write_conversion_new_var_intern<'b, W: std::io::Write,
2458                 LP: Fn(&str, bool) -> Option<(&str, &str)>,
2459                 LC: Fn(&str, bool, Option<&syn::Type>, &syn::Ident, &str) ->  Option<(&'b str, Vec<(String, String)>, &'b str, ContainerPrefixLocation)>,
2460                 VP: Fn(&mut W, &syn::Type, Option<&GenericTypes>, bool, bool, bool),
2461                 VS: Fn(&mut W, &syn::Type, Option<&GenericTypes>, bool, bool, bool)>
2462                         (&self, w: &mut W, ident: &syn::Ident, var: &str, t: &syn::Type, generics: Option<&GenericTypes>,
2463                          mut is_ref: bool, mut ptr_for_ref: bool, to_c: bool, from_ownable_ref: bool,
2464                          path_lookup: &LP, container_lookup: &LC, var_prefix: &VP, var_suffix: &VS) -> bool {
2465
2466                 macro_rules! convert_container {
2467                         ($container_type: expr, $args_len: expr, $args_iter: expr) => { {
2468                                 // For slices (and Options), we refuse to directly map them as is_ref when they
2469                                 // aren't opaque types containing an inner pointer. This is due to the fact that,
2470                                 // in both cases, the actual higher-level type is non-is_ref.
2471                                 let (ty_has_inner, ty_is_trait) = if $args_len == 1 {
2472                                         let ty = $args_iter().next().unwrap();
2473                                         if $container_type == "Slice" && to_c {
2474                                                 // "To C ptr_for_ref" means "return the regular object with is_owned
2475                                                 // set to false", which is totally what we want in a slice if we're about to
2476                                                 // set ty_has_inner.
2477                                                 ptr_for_ref = true;
2478                                         }
2479                                         if let syn::Type::Reference(t) = ty {
2480                                                 if let syn::Type::Path(p) = &*t.elem {
2481                                                         let resolved = self.resolve_path(&p.path, generics);
2482                                                         (self.c_type_has_inner_from_path(&resolved), self.crate_types.traits.get(&resolved).is_some())
2483                                                 } else { (false, false) }
2484                                         } else if let syn::Type::Path(p) = ty {
2485                                                 let resolved = self.resolve_path(&p.path, generics);
2486                                                 (self.c_type_has_inner_from_path(&resolved), self.crate_types.traits.get(&resolved).is_some())
2487                                         } else { (false, false) }
2488                                 } else { (true, false) };
2489
2490                                 // Options get a bunch of special handling, since in general we map Option<>al
2491                                 // types into the same C type as non-Option-wrapped types. This ends up being
2492                                 // pretty manual here and most of the below special-cases are for Options.
2493                                 let mut needs_ref_map = false;
2494                                 let mut only_contained_type = None;
2495                                 let mut only_contained_type_nonref = None;
2496                                 let mut only_contained_has_inner = false;
2497                                 let mut contains_slice = false;
2498                                 if $args_len == 1 {
2499                                         only_contained_has_inner = ty_has_inner;
2500                                         let arg = $args_iter().next().unwrap();
2501                                         if let syn::Type::Reference(t) = arg {
2502                                                 only_contained_type = Some(arg);
2503                                                 only_contained_type_nonref = Some(&*t.elem);
2504                                                 if let syn::Type::Path(_) = &*t.elem {
2505                                                         is_ref = true;
2506                                                 } else if let syn::Type::Slice(_) = &*t.elem {
2507                                                         contains_slice = true;
2508                                                 } else { return false; }
2509                                                 // If the inner element contains an inner pointer, we will just use that,
2510                                                 // avoiding the need to map elements to references. Otherwise we'll need to
2511                                                 // do an extra mapping step.
2512                                                 needs_ref_map = !only_contained_has_inner && !ty_is_trait && $container_type == "Option";
2513                                         } else {
2514                                                 only_contained_type = Some(arg);
2515                                                 only_contained_type_nonref = Some(arg);
2516                                         }
2517                                 }
2518
2519                                 if let Some((prefix, conversions, suffix, prefix_location)) = container_lookup(&$container_type, is_ref, only_contained_type, ident, var) {
2520                                         assert_eq!(conversions.len(), $args_len);
2521                                         write!(w, "let mut local_{}{} = ", ident,
2522                                                 if (!to_c && needs_ref_map) || (to_c && $container_type == "Option" && contains_slice) {"_base"} else { "" }).unwrap();
2523                                         if prefix_location == ContainerPrefixLocation::OutsideConv {
2524                                                 var_prefix(w, $args_iter().next().unwrap(), generics, is_ref, true, true);
2525                                         }
2526                                         write!(w, "{}{}", prefix, var).unwrap();
2527
2528                                         for ((pfx, var_name), (idx, ty)) in conversions.iter().zip($args_iter().enumerate()) {
2529                                                 let mut var = std::io::Cursor::new(Vec::new());
2530                                                 write!(&mut var, "{}", var_name).unwrap();
2531                                                 let var_access = String::from_utf8(var.into_inner()).unwrap();
2532
2533                                                 let conv_ty = if needs_ref_map { only_contained_type_nonref.as_ref().unwrap() } else { ty };
2534
2535                                                 write!(w, "{} {{ ", pfx).unwrap();
2536                                                 let new_var_name = format!("{}_{}", ident, idx);
2537                                                 let new_var = self.write_conversion_new_var_intern(w, &format_ident!("{}", new_var_name),
2538                                                                 &var_access, conv_ty, generics, contains_slice || (is_ref && ty_has_inner), ptr_for_ref,
2539                                                                 to_c, from_ownable_ref, path_lookup, container_lookup, var_prefix, var_suffix);
2540                                                 if new_var { write!(w, " ").unwrap(); }
2541
2542                                                 if prefix_location == ContainerPrefixLocation::PerConv {
2543                                                         var_prefix(w, conv_ty, generics, is_ref && ty_has_inner, ptr_for_ref, false);
2544                                                 } else if !is_ref && !needs_ref_map && to_c && only_contained_has_inner {
2545                                                         write!(w, "ObjOps::heap_alloc(").unwrap();
2546                                                 }
2547
2548                                                 write!(w, "{}{}", if contains_slice && !to_c { "local_" } else { "" }, if new_var { new_var_name } else { var_access }).unwrap();
2549                                                 if prefix_location == ContainerPrefixLocation::PerConv {
2550                                                         var_suffix(w, conv_ty, generics, is_ref && ty_has_inner, ptr_for_ref, false);
2551                                                 } else if !is_ref && !needs_ref_map && to_c && only_contained_has_inner {
2552                                                         write!(w, ")").unwrap();
2553                                                 }
2554                                                 write!(w, " }}").unwrap();
2555                                         }
2556                                         write!(w, "{}", suffix).unwrap();
2557                                         if prefix_location == ContainerPrefixLocation::OutsideConv {
2558                                                 var_suffix(w, $args_iter().next().unwrap(), generics, is_ref, ptr_for_ref, true);
2559                                         }
2560                                         write!(w, ";").unwrap();
2561                                         if !to_c && needs_ref_map {
2562                                                 write!(w, " let mut local_{} = local_{}_base.as_ref()", ident, ident).unwrap();
2563                                                 if contains_slice {
2564                                                         write!(w, ".map(|a| &a[..])").unwrap();
2565                                                 }
2566                                                 write!(w, ";").unwrap();
2567                                         } else if to_c && $container_type == "Option" && contains_slice {
2568                                                 write!(w, " let mut local_{} = *local_{}_base;", ident, ident).unwrap();
2569                                         }
2570                                         return true;
2571                                 }
2572                         } }
2573                 }
2574
2575                 match generics.resolve_type(t) {
2576                         syn::Type::Reference(r) => {
2577                                 if let syn::Type::Slice(_) = &*r.elem {
2578                                         self.write_conversion_new_var_intern(w, ident, var, &*r.elem, generics, is_ref, ptr_for_ref, to_c, from_ownable_ref, path_lookup, container_lookup, var_prefix, var_suffix)
2579                                 } else {
2580                                         self.write_conversion_new_var_intern(w, ident, var, &*r.elem, generics, true, ptr_for_ref, to_c, from_ownable_ref, path_lookup, container_lookup, var_prefix, var_suffix)
2581                                 }
2582                         },
2583                         syn::Type::Path(p) => {
2584                                 if p.qself.is_some() {
2585                                         unimplemented!();
2586                                 }
2587                                 let resolved_path = self.resolve_path(&p.path, generics);
2588                                 if let Some(aliased_type) = self.crate_types.type_aliases.get(&resolved_path) {
2589                                         return self.write_conversion_new_var_intern(w, ident, var, aliased_type, None, is_ref, ptr_for_ref, to_c, from_ownable_ref, path_lookup, container_lookup, var_prefix, var_suffix);
2590                                 }
2591                                 if self.is_known_container(&resolved_path, is_ref) || self.is_path_transparent_container(&p.path, generics, is_ref) {
2592                                         if let syn::PathArguments::AngleBracketed(args) = &p.path.segments.iter().next().unwrap().arguments {
2593                                                 convert_container!(resolved_path, args.args.len(), || args.args.iter().map(|arg| {
2594                                                         if let syn::GenericArgument::Type(ty) = arg {
2595                                                                 generics.resolve_type(ty)
2596                                                         } else { unimplemented!(); }
2597                                                 }));
2598                                         } else { unimplemented!(); }
2599                                 }
2600                                 if self.is_primitive(&resolved_path) {
2601                                         false
2602                                 } else if let Some(ty_ident) = single_ident_generic_path_to_ident(&p.path) {
2603                                         if let Some((prefix, suffix)) = path_lookup(&resolved_path, is_ref) {
2604                                                 write!(w, "let mut local_{} = {}{}{};", ident, prefix, var, suffix).unwrap();
2605                                                 true
2606                                         } else if self.types.maybe_resolve_declared(ty_ident).is_some() {
2607                                                 false
2608                                         } else { false }
2609                                 } else { false }
2610                         },
2611                         syn::Type::Array(_) => {
2612                                 // We assume all arrays contain only primitive types.
2613                                 // This may result in some outputs not compiling.
2614                                 false
2615                         },
2616                         syn::Type::Slice(s) => {
2617                                 if let syn::Type::Path(p) = &*s.elem {
2618                                         let resolved = self.resolve_path(&p.path, generics);
2619                                         if self.is_primitive(&resolved) {
2620                                                 let slice_path = format!("[{}]", resolved);
2621                                                 if let Some((prefix, suffix)) = path_lookup(&slice_path, true) {
2622                                                         write!(w, "let mut local_{} = {}{}{};", ident, prefix, var, suffix).unwrap();
2623                                                         true
2624                                                 } else { false }
2625                                         } else {
2626                                                 let tyref = [&*s.elem];
2627                                                 if to_c {
2628                                                         // If we're converting from a slice to a Vec, assume we can clone the
2629                                                         // elements and clone them into a new Vec first. Next we'll walk the
2630                                                         // new Vec here and convert them to C types.
2631                                                         write!(w, "let mut local_{}_clone = Vec::new(); local_{}_clone.extend_from_slice({}); let mut {} = local_{}_clone; ", ident, ident, ident, ident, ident).unwrap();
2632                                                 }
2633                                                 is_ref = false;
2634                                                 convert_container!("Vec", 1, || tyref.iter().map(|t| generics.resolve_type(*t)));
2635                                                 unimplemented!("convert_container should return true as container_lookup should succeed for slices");
2636                                         }
2637                                 } else if let syn::Type::Reference(ty) = &*s.elem {
2638                                         let tyref = if from_ownable_ref || !to_c { [&*ty.elem] } else { [&*s.elem] };
2639                                         is_ref = true;
2640                                         convert_container!("Slice", 1, || tyref.iter().map(|t| generics.resolve_type(*t)));
2641                                         unimplemented!("convert_container should return true as container_lookup should succeed for slices");
2642                                 } else if let syn::Type::Tuple(t) = &*s.elem {
2643                                         // When mapping into a temporary new var, we need to own all the underlying objects.
2644                                         // Thus, we drop any references inside the tuple and convert with non-reference types.
2645                                         let mut elems = syn::punctuated::Punctuated::new();
2646                                         for elem in t.elems.iter() {
2647                                                 if let syn::Type::Reference(r) = elem {
2648                                                         elems.push((*r.elem).clone());
2649                                                 } else {
2650                                                         elems.push(elem.clone());
2651                                                 }
2652                                         }
2653                                         let ty = [syn::Type::Tuple(syn::TypeTuple {
2654                                                 paren_token: t.paren_token, elems
2655                                         })];
2656                                         is_ref = false;
2657                                         ptr_for_ref = true;
2658                                         convert_container!("Slice", 1, || ty.iter());
2659                                         unimplemented!("convert_container should return true as container_lookup should succeed for slices");
2660                                 } else if let syn::Type::Array(_) = &*s.elem {
2661                                         is_ref = false;
2662                                         ptr_for_ref = true;
2663                                         let arr_elem = [(*s.elem).clone()];
2664                                         convert_container!("Slice", 1, || arr_elem.iter());
2665                                         unimplemented!("convert_container should return true as container_lookup should succeed for slices");
2666                                 } else { unimplemented!() }
2667                         },
2668                         syn::Type::Tuple(t) => {
2669                                 if !t.elems.is_empty() {
2670                                         // We don't (yet) support tuple elements which cannot be converted inline
2671                                         write!(w, "let (").unwrap();
2672                                         for idx in 0..t.elems.len() {
2673                                                 if idx != 0 { write!(w, ", ").unwrap(); }
2674                                                 write!(w, "{} orig_{}_{}", if is_ref { "ref" } else { "mut" }, ident, idx).unwrap();
2675                                         }
2676                                         write!(w, ") = {}{}; ", var, if !to_c { ".to_rust()" } else { "" }).unwrap();
2677                                         // Like other template types, tuples are always mapped as their non-ref
2678                                         // versions for types which have different ref mappings. Thus, we convert to
2679                                         // non-ref versions and handle opaque types with inner pointers manually.
2680                                         for (idx, elem) in t.elems.iter().enumerate() {
2681                                                 if let syn::Type::Path(p) = elem {
2682                                                         let v_name = format!("orig_{}_{}", ident, idx);
2683                                                         let tuple_elem_ident = format_ident!("{}", &v_name);
2684                                                         if self.write_conversion_new_var_intern(w, &tuple_elem_ident, &v_name, elem, generics,
2685                                                                         false, ptr_for_ref, to_c, from_ownable_ref,
2686                                                                         path_lookup, container_lookup, var_prefix, var_suffix) {
2687                                                                 write!(w, " ").unwrap();
2688                                                                 // Opaque types with inner pointers shouldn't ever create new stack
2689                                                                 // variables, so we don't handle it and just assert that it doesn't
2690                                                                 // here.
2691                                                                 assert!(!self.c_type_has_inner_from_path(&self.resolve_path(&p.path, generics)));
2692                                                         }
2693                                                 }
2694                                         }
2695                                         write!(w, "let mut local_{} = (", ident).unwrap();
2696                                         for (idx, elem) in t.elems.iter().enumerate() {
2697                                                 let real_elem = generics.resolve_type(&elem);
2698                                                 let ty_has_inner = {
2699                                                                 if to_c {
2700                                                                         // "To C ptr_for_ref" means "return the regular object with
2701                                                                         // is_owned set to false", which is totally what we want
2702                                                                         // if we're about to set ty_has_inner.
2703                                                                         ptr_for_ref = true;
2704                                                                 }
2705                                                                 if let syn::Type::Reference(t) = real_elem {
2706                                                                         if let syn::Type::Path(p) = &*t.elem {
2707                                                                                 self.c_type_has_inner_from_path(&self.resolve_path(&p.path, generics))
2708                                                                         } else { false }
2709                                                                 } else if let syn::Type::Path(p) = real_elem {
2710                                                                         self.c_type_has_inner_from_path(&self.resolve_path(&p.path, generics))
2711                                                                 } else { false }
2712                                                         };
2713                                                 if idx != 0 { write!(w, ", ").unwrap(); }
2714                                                 var_prefix(w, real_elem, generics, is_ref && ty_has_inner, ptr_for_ref, false);
2715                                                 if is_ref && ty_has_inner {
2716                                                         // For ty_has_inner, the regular var_prefix mapping will take a
2717                                                         // reference, so deref once here to make sure we keep the original ref.
2718                                                         write!(w, "*").unwrap();
2719                                                 }
2720                                                 write!(w, "orig_{}_{}", ident, idx).unwrap();
2721                                                 if is_ref && !ty_has_inner {
2722                                                         // If we don't have an inner variable's reference to maintain, just
2723                                                         // hope the type is Clonable and use that.
2724                                                         write!(w, ".clone()").unwrap();
2725                                                 }
2726                                                 var_suffix(w, real_elem, generics, is_ref && ty_has_inner, ptr_for_ref, false);
2727                                         }
2728                                         write!(w, "){};", if to_c { ".into()" } else { "" }).unwrap();
2729                                         true
2730                                 } else { false }
2731                         },
2732                         _ => unimplemented!(),
2733                 }
2734         }
2735
2736         pub fn write_to_c_conversion_new_var_inner<W: std::io::Write>(&self, w: &mut W, ident: &syn::Ident, var_access: &str, t: &syn::Type, generics: Option<&GenericTypes>, ptr_for_ref: bool, from_ownable_ref: bool) -> bool {
2737                 self.write_conversion_new_var_intern(w, ident, var_access, t, generics, from_ownable_ref, ptr_for_ref, true, from_ownable_ref,
2738                         &|a, b| self.to_c_conversion_new_var_from_path(a, b),
2739                         &|a, b, c, d, e| self.to_c_conversion_container_new_var(generics, a, b, c, d, e),
2740                         // We force ptr_for_ref here since we can't generate a ref on one line and use it later
2741                         &|a, b, c, d, e, f| self.write_to_c_conversion_inline_prefix_inner(a, b, c, d, e, f),
2742                         &|a, b, c, d, e, f| self.write_to_c_conversion_inline_suffix_inner(a, b, c, d, e, f))
2743         }
2744         pub fn write_to_c_conversion_new_var<W: std::io::Write>(&self, w: &mut W, ident: &syn::Ident, t: &syn::Type, generics: Option<&GenericTypes>, ptr_for_ref: bool) -> bool {
2745                 self.write_to_c_conversion_new_var_inner(w, ident, &format!("{}", ident), t, generics, ptr_for_ref, false)
2746         }
2747         /// Prints new-var conversion for an "ownable_ref" type, ie prints conversion for
2748         /// `create_ownable_reference(t)`, not `t` itself.
2749         pub fn write_to_c_conversion_from_ownable_ref_new_var<W: std::io::Write>(&self, w: &mut W, ident: &syn::Ident, t: &syn::Type, generics: Option<&GenericTypes>) -> bool {
2750                 self.write_to_c_conversion_new_var_inner(w, ident, &format!("{}", ident), t, generics, true, true)
2751         }
2752         pub fn write_from_c_conversion_new_var<W: std::io::Write>(&self, w: &mut W, ident: &syn::Ident, t: &syn::Type, generics: Option<&GenericTypes>) -> bool {
2753                 self.write_conversion_new_var_intern(w, ident, &format!("{}", ident), t, generics, false, false, false, false,
2754                         &|a, b| self.from_c_conversion_new_var_from_path(a, b),
2755                         &|a, b, c, d, e| self.from_c_conversion_container_new_var(generics, a, b, c, d, e),
2756                         // We force ptr_for_ref here since we can't generate a ref on one line and use it later
2757                         &|a, b, c, d, e, _f| self.write_from_c_conversion_prefix_inner(a, b, c, d, e),
2758                         &|a, b, c, d, e, _f| self.write_from_c_conversion_suffix_inner(a, b, c, d, e))
2759         }
2760
2761         // ******************************************************
2762         // *** C Container Type Equivalent and alias Printing ***
2763         // ******************************************************
2764
2765         fn write_template_generics<'b, W: std::io::Write>(&self, w: &mut W, args: &mut dyn Iterator<Item=&'b syn::Type>, generics: Option<&GenericTypes>, is_ref: bool) -> bool {
2766                 for (idx, orig_t) in args.enumerate() {
2767                         if idx != 0 {
2768                                 write!(w, ", ").unwrap();
2769                         }
2770                         let t = generics.resolve_type(orig_t);
2771                         if let syn::Type::Reference(r_arg) = t {
2772                                 assert!(!is_ref); // We don't currently support outer reference types for non-primitive inners
2773
2774                                 if !self.write_c_type_intern(w, &*r_arg.elem, generics, false, false, false, true, true) { return false; }
2775
2776                                 // While write_c_type_intern, above is correct, we don't want to blindly convert a
2777                                 // reference to something stupid, so check that the container is either opaque or a
2778                                 // predefined type (currently only Transaction).
2779                                 if let syn::Type::Path(p_arg) = &*r_arg.elem {
2780                                         let resolved = self.resolve_path(&p_arg.path, generics);
2781                                         assert!(self.crate_types.opaques.get(&resolved).is_some() ||
2782                                                         self.crate_types.traits.get(&resolved).is_some() ||
2783                                                         self.c_type_from_path(&resolved, true, true).is_some(), "Template generics should be opaque or have a predefined mapping");
2784                                 } else { unimplemented!(); }
2785                         } else if let syn::Type::Path(p_arg) = t {
2786                                 if let Some(resolved) = self.maybe_resolve_path(&p_arg.path, generics) {
2787                                         if !self.is_primitive(&resolved) && self.c_type_from_path(&resolved, false, false).is_none() {
2788                                                 if is_ref {
2789                                                         // We don't currently support outer reference types for non-primitive inners
2790                                                         return false;
2791                                                 }
2792                                         }
2793                                 } else {
2794                                         return false;
2795                                 }
2796                                 if !self.write_c_type_intern(w, t, generics, false, false, false, true, true) { return false; }
2797                         } else {
2798                                 // We don't currently support outer reference types for non-primitive inners,
2799                                 // except for the empty tuple.
2800                                 if let syn::Type::Tuple(t_arg) = t {
2801                                         assert!(t_arg.elems.len() == 0 || !is_ref);
2802                                 } else {
2803                                         assert!(!is_ref);
2804                                 }
2805                                 if !self.write_c_type_intern(w, t, generics, false, false, false, true, true) { return false; }
2806                         }
2807                 }
2808                 true
2809         }
2810         fn check_create_container(&self, mangled_container: String, container_type: &str, args: Vec<&syn::Type>, generics: Option<&GenericTypes>, is_ref: bool) -> bool {
2811                 if !self.crate_types.templates_defined.borrow().get(&mangled_container).is_some() {
2812                         let mut created_container: Vec<u8> = Vec::new();
2813
2814                         if container_type == "Result" {
2815                                 let mut a_ty: Vec<u8> = Vec::new();
2816                                 if let syn::Type::Tuple(tup) = args.iter().next().unwrap() {
2817                                         if tup.elems.is_empty() {
2818                                                 write!(&mut a_ty, "()").unwrap();
2819                                         } else {
2820                                                 if !self.write_template_generics(&mut a_ty, &mut args.iter().map(|t| *t).take(1), generics, is_ref) { return false; }
2821                                         }
2822                                 } else {
2823                                         if !self.write_template_generics(&mut a_ty, &mut args.iter().map(|t| *t).take(1), generics, is_ref) { return false; }
2824                                 }
2825
2826                                 let mut b_ty: Vec<u8> = Vec::new();
2827                                 if let syn::Type::Tuple(tup) = args.iter().skip(1).next().unwrap() {
2828                                         if tup.elems.is_empty() {
2829                                                 write!(&mut b_ty, "()").unwrap();
2830                                         } else {
2831                                                 if !self.write_template_generics(&mut b_ty, &mut args.iter().map(|t| *t).skip(1), generics, is_ref) { return false; }
2832                                         }
2833                                 } else {
2834                                         if !self.write_template_generics(&mut b_ty, &mut args.iter().map(|t| *t).skip(1), generics, is_ref) { return false; }
2835                                 }
2836
2837                                 let ok_str = String::from_utf8(a_ty).unwrap();
2838                                 let err_str = String::from_utf8(b_ty).unwrap();
2839                                 let is_clonable = self.is_clonable(&ok_str) && self.is_clonable(&err_str);
2840                                 write_result_block(&mut created_container, &mangled_container, &ok_str, &err_str, is_clonable);
2841                                 if is_clonable {
2842                                         self.crate_types.set_clonable(Self::generated_container_path().to_owned() + "::" + &mangled_container);
2843                                 }
2844                         } else if container_type == "Vec" {
2845                                 let mut a_ty: Vec<u8> = Vec::new();
2846                                 if !self.write_template_generics(&mut a_ty, &mut args.iter().map(|t| *t), generics, is_ref) { return false; }
2847                                 let ty = String::from_utf8(a_ty).unwrap();
2848                                 let is_clonable = self.is_clonable(&ty);
2849                                 write_vec_block(&mut created_container, &mangled_container, &ty, is_clonable);
2850                                 if is_clonable {
2851                                         self.crate_types.set_clonable(Self::generated_container_path().to_owned() + "::" + &mangled_container);
2852                                 }
2853                         } else if container_type.ends_with("Tuple") {
2854                                 let mut tuple_args = Vec::new();
2855                                 let mut is_clonable = true;
2856                                 for arg in args.iter() {
2857                                         let mut ty: Vec<u8> = Vec::new();
2858                                         if !self.write_template_generics(&mut ty, &mut [arg].iter().map(|t| **t), generics, is_ref) { return false; }
2859                                         let ty_str = String::from_utf8(ty).unwrap();
2860                                         if !self.is_clonable(&ty_str) {
2861                                                 is_clonable = false;
2862                                         }
2863                                         tuple_args.push(ty_str);
2864                                 }
2865                                 write_tuple_block(&mut created_container, &mangled_container, &tuple_args, is_clonable);
2866                                 if is_clonable {
2867                                         self.crate_types.set_clonable(Self::generated_container_path().to_owned() + "::" + &mangled_container);
2868                                 }
2869                         } else if container_type == "Option" {
2870                                 let mut a_ty: Vec<u8> = Vec::new();
2871                                 if !self.write_template_generics(&mut a_ty, &mut args.iter().map(|t| *t), generics, is_ref) { return false; }
2872                                 let ty = String::from_utf8(a_ty).unwrap();
2873                                 let is_clonable = self.is_clonable(&ty);
2874                                 write_option_block(&mut created_container, &mangled_container, &ty, is_clonable);
2875                                 if is_clonable {
2876                                         self.crate_types.set_clonable(Self::generated_container_path().to_owned() + "::" + &mangled_container);
2877                                 }
2878                         } else {
2879                                 unreachable!();
2880                         }
2881                         self.crate_types.write_new_template(mangled_container.clone(), true, &created_container);
2882                 }
2883                 true
2884         }
2885         fn path_to_generic_args(path: &syn::Path) -> Vec<&syn::Type> {
2886                 if let syn::PathArguments::AngleBracketed(args) = &path.segments.iter().next().unwrap().arguments {
2887                         args.args.iter().map(|gen| if let syn::GenericArgument::Type(t) = gen { t } else { unimplemented!() }).collect()
2888                 } else { unimplemented!(); }
2889         }
2890         fn write_c_mangled_container_path_intern<W: std::io::Write>
2891                         (&self, w: &mut W, args: Vec<&syn::Type>, generics: Option<&GenericTypes>, ident: &str, is_ref: bool, is_mut: bool, ptr_for_ref: bool, in_type: bool) -> bool {
2892                 let mut mangled_type: Vec<u8> = Vec::new();
2893                 if !self.is_transparent_container(ident, is_ref, args.iter().map(|a| *a), generics) {
2894                         write!(w, "C{}_", ident).unwrap();
2895                         write!(mangled_type, "C{}_", ident).unwrap();
2896                 } else { assert_eq!(args.len(), 1); }
2897                 for arg in args.iter() {
2898                         macro_rules! write_path {
2899                                 ($p_arg: expr, $extra_write: expr) => {
2900                                         if let Some(subtype) = self.maybe_resolve_path(&$p_arg.path, generics) {
2901                                                 if self.is_transparent_container(ident, is_ref, args.iter().map(|a| *a), generics) {
2902                                                         if !in_type {
2903                                                                 if self.c_type_has_inner_from_path(&subtype) {
2904                                                                         if !self.write_c_path_intern(w, &$p_arg.path, generics, is_ref, is_mut, ptr_for_ref, false, true) { return false; }
2905                                                                 } else {
2906                                                                         // Option<T> needs to be converted to a *mut T, ie mut ptr-for-ref
2907                                                                         if !self.write_c_path_intern(w, &$p_arg.path, generics, true, true, true, false, true) { return false; }
2908                                                                 }
2909                                                         } else {
2910                                                                 write!(w, "{}", $p_arg.path.segments.last().unwrap().ident).unwrap();
2911                                                         }
2912                                                 } else if self.is_known_container(&subtype, is_ref) || self.is_path_transparent_container(&$p_arg.path, generics, is_ref) {
2913                                                         if !self.write_c_mangled_container_path_intern(w, Self::path_to_generic_args(&$p_arg.path), generics,
2914                                                                         &subtype, is_ref, is_mut, ptr_for_ref, true) {
2915                                                                 return false;
2916                                                         }
2917                                                         self.write_c_mangled_container_path_intern(&mut mangled_type, Self::path_to_generic_args(&$p_arg.path),
2918                                                                 generics, &subtype, is_ref, is_mut, ptr_for_ref, true);
2919                                                         if let Some(w2) = $extra_write as Option<&mut Vec<u8>> {
2920                                                                 self.write_c_mangled_container_path_intern(w2, Self::path_to_generic_args(&$p_arg.path),
2921                                                                         generics, &subtype, is_ref, is_mut, ptr_for_ref, true);
2922                                                         }
2923                                                 } else {
2924                                                         let mut resolved = Vec::new();
2925                                                         let id =
2926                                                                 if self.write_c_path_intern(&mut resolved, &$p_arg.path, generics, false, false, false, false, false) {
2927                                                                         let inner = std::str::from_utf8(&resolved).unwrap();
2928                                                                         inner.rsplitn(2, "::").next().unwrap()
2929                                                                 } else {
2930                                                                         subtype.rsplitn(2, "::").next().unwrap()
2931                                                                 };
2932                                                         write!(w, "{}", id).unwrap();
2933                                                         write!(mangled_type, "{}", id).unwrap();
2934                                                         if let Some(w2) = $extra_write as Option<&mut Vec<u8>> {
2935                                                                 write!(w2, "{}", id).unwrap();
2936                                                         }
2937                                                 }
2938                                         } else { return false; }
2939                                 }
2940                         }
2941                         match generics.resolve_type(arg) {
2942                                 syn::Type::Tuple(tuple) => {
2943                                         if tuple.elems.len() == 0 {
2944                                                 write!(w, "None").unwrap();
2945                                                 write!(mangled_type, "None").unwrap();
2946                                         } else {
2947                                                 let mut mangled_tuple_type: Vec<u8> = Vec::new();
2948
2949                                                 // Figure out what the mangled type should look like. To disambiguate
2950                                                 // ((A, B), C) and (A, B, C) we prefix the generic args with a _ and suffix
2951                                                 // them with a Z. Ideally we wouldn't use Z, but not many special chars are
2952                                                 // available for use in type names.
2953                                                 write!(w, "C{}Tuple_", tuple.elems.len()).unwrap();
2954                                                 write!(mangled_type, "C{}Tuple_", tuple.elems.len()).unwrap();
2955                                                 write!(mangled_tuple_type, "C{}Tuple_", tuple.elems.len()).unwrap();
2956                                                 for elem in tuple.elems.iter() {
2957                                                         if let syn::Type::Path(p) = elem {
2958                                                                 write_path!(p, Some(&mut mangled_tuple_type));
2959                                                         } else if let syn::Type::Reference(refelem) = elem {
2960                                                                 if let syn::Type::Path(p) = &*refelem.elem {
2961                                                                         write_path!(p, Some(&mut mangled_tuple_type));
2962                                                                 } else { return false; }
2963                                                         } else if let syn::Type::Array(_) = elem {
2964                                                                 let mut resolved = Vec::new();
2965                                                                 if !self.write_c_type_intern(&mut resolved, &elem, generics, false, false, false, false, false) { return false; }
2966                                                                 let array_inner = String::from_utf8(resolved).unwrap();
2967                                                                 let arr_name = array_inner.rsplitn(2, "::").next().unwrap();
2968                                                                 write!(w, "{}", arr_name).unwrap();
2969                                                                 write!(mangled_type, "{}", arr_name).unwrap();
2970                                                         } else { return false; }
2971                                                 }
2972                                                 write!(w, "Z").unwrap();
2973                                                 write!(mangled_type, "Z").unwrap();
2974                                                 write!(mangled_tuple_type, "Z").unwrap();
2975                                                 if !self.check_create_container(String::from_utf8(mangled_tuple_type).unwrap(),
2976                                                                 &format!("{}Tuple", tuple.elems.len()), tuple.elems.iter().collect(), generics, is_ref) {
2977                                                         return false;
2978                                                 }
2979                                         }
2980                                 },
2981                                 syn::Type::Path(p_arg) => {
2982                                         write_path!(p_arg, None);
2983                                 },
2984                                 syn::Type::Reference(refty) => {
2985                                         if let syn::Type::Path(p_arg) = &*refty.elem {
2986                                                 write_path!(p_arg, None);
2987                                         } else if let syn::Type::Slice(_) = &*refty.elem {
2988                                                 // write_c_type will actually do exactly what we want here, we just need to
2989                                                 // make it a pointer so that its an option. Note that we cannot always convert
2990                                                 // the Vec-as-slice (ie non-ref types) containers, so sometimes need to be able
2991                                                 // to edit it, hence we use *mut here instead of *const.
2992                                                 if args.len() != 1 { return false; }
2993                                                 write!(w, "*mut ").unwrap();
2994                                                 self.write_c_type(w, arg, None, true);
2995                                         } else { return false; }
2996                                 },
2997                                 syn::Type::Array(a) => {
2998                                         if let syn::Type::Path(p_arg) = &*a.elem {
2999                                                 let resolved = self.resolve_path(&p_arg.path, generics);
3000                                                 if !self.is_primitive(&resolved) { return false; }
3001                                                 if let syn::Expr::Lit(syn::ExprLit { lit: syn::Lit::Int(len), .. }) = &a.len {
3002                                                         if self.c_type_from_path(&format!("[{}; {}]", resolved, len.base10_digits()), is_ref, ptr_for_ref).is_none() { return false; }
3003                                                         if in_type || args.len() != 1 {
3004                                                                 write!(w, "_{}{}", resolved, len.base10_digits()).unwrap();
3005                                                                 write!(mangled_type, "_{}{}", resolved, len.base10_digits()).unwrap();
3006                                                         } else {
3007                                                                 let arrty = format!("[{}; {}]", resolved, len.base10_digits());
3008                                                                 let realty = self.c_type_from_path(&arrty, is_ref, ptr_for_ref).unwrap_or(&arrty);
3009                                                                 write!(w, "{}", realty).unwrap();
3010                                                                 write!(mangled_type, "{}", realty).unwrap();
3011                                                         }
3012                                                 } else { return false; }
3013                                         } else { return false; }
3014                                 },
3015                                 _ => { return false; },
3016                         }
3017                 }
3018                 if self.is_transparent_container(ident, is_ref, args.iter().map(|a| *a), generics) { return true; }
3019                 // Push the "end of type" Z
3020                 write!(w, "Z").unwrap();
3021                 write!(mangled_type, "Z").unwrap();
3022
3023                 // Make sure the type is actually defined:
3024                 self.check_create_container(String::from_utf8(mangled_type).unwrap(), ident, args, generics, is_ref)
3025         }
3026         fn write_c_mangled_container_path<W: std::io::Write>(&self, w: &mut W, args: Vec<&syn::Type>, generics: Option<&GenericTypes>, ident: &str, is_ref: bool, is_mut: bool, ptr_for_ref: bool) -> bool {
3027                 if !self.is_transparent_container(ident, is_ref, args.iter().map(|a| *a), generics) {
3028                         write!(w, "{}::", Self::generated_container_path()).unwrap();
3029                 }
3030                 self.write_c_mangled_container_path_intern(w, args, generics, ident, is_ref, is_mut, ptr_for_ref, false)
3031         }
3032         pub fn get_c_mangled_container_type(&self, args: Vec<&syn::Type>, generics: Option<&GenericTypes>, template_name: &str) -> Option<String> {
3033                 let mut out = Vec::new();
3034                 if !self.write_c_mangled_container_path(&mut out, args, generics, template_name, false, false, false) {
3035                         return None;
3036                 }
3037                 Some(String::from_utf8(out).unwrap())
3038         }
3039
3040         // **********************************
3041         // *** C Type Equivalent Printing ***
3042         // **********************************
3043
3044         fn write_c_path_intern<W: std::io::Write>(&self, w: &mut W, path: &syn::Path, generics: Option<&GenericTypes>, is_ref: bool, is_mut: bool, ptr_for_ref: bool, with_ref_lifetime: bool, c_ty: bool) -> bool {
3045                 let full_path = match self.maybe_resolve_path(&path, generics) {
3046                         Some(path) => path, None => return false };
3047                 if let Some(c_type) = self.c_type_from_path(&full_path, is_ref, ptr_for_ref) {
3048                         write!(w, "{}", c_type).unwrap();
3049                         true
3050                 } else if self.crate_types.traits.get(&full_path).is_some() {
3051                         // Note that we always use the crate:: prefix here as we are always referring to a
3052                         // concrete object which is of the generated type, it just implements the upstream
3053                         // type.
3054                         if is_ref && ptr_for_ref {
3055                                 write!(w, "*{} crate::{}", if is_mut { "mut" } else { "const" }, full_path).unwrap();
3056                         } else if is_ref {
3057                                 if with_ref_lifetime { unimplemented!(); }
3058                                 write!(w, "&{}crate::{}", if is_mut { "mut " } else { "" }, full_path).unwrap();
3059                         } else {
3060                                 write!(w, "crate::{}", full_path).unwrap();
3061                         }
3062                         true
3063                 } else if self.crate_types.opaques.get(&full_path).is_some() || self.crate_types.mirrored_enums.get(&full_path).is_some() {
3064                         let crate_pfx = if c_ty { "crate::" } else { "" };
3065                         if is_ref && ptr_for_ref {
3066                                 // ptr_for_ref implies we're returning the object, which we can't really do for
3067                                 // opaque or mirrored types without box'ing them, which is quite a waste, so return
3068                                 // the actual object itself (for opaque types we'll set the pointer to the actual
3069                                 // type and note that its a reference).
3070                                 write!(w, "{}{}", crate_pfx, full_path).unwrap();
3071                         } else if is_ref && with_ref_lifetime {
3072                                 assert!(!is_mut);
3073                                 // If we're concretizing something with a lifetime parameter, we have to pick a
3074                                 // lifetime, of which the only real available choice is `static`, obviously.
3075                                 write!(w, "&'static {}", crate_pfx).unwrap();
3076                                 if !c_ty {
3077                                         self.write_rust_path(w, generics, path, with_ref_lifetime, false);
3078                                 } else {
3079                                         // We shouldn't be mapping references in types, so panic here
3080                                         unimplemented!();
3081                                 }
3082                         } else if is_ref {
3083                                 write!(w, "&{}{}{}", if is_mut { "mut " } else { "" }, crate_pfx, full_path).unwrap();
3084                         } else {
3085                                 write!(w, "{}{}", crate_pfx, full_path).unwrap();
3086                         }
3087                         true
3088                 } else {
3089                         if let Some(trait_impls) = self.crate_types.traits_impld.get(&full_path) {
3090                                 if trait_impls.len() == 1 {
3091                                         // If this is a no-export'd crate and there's only one implementation in the
3092                                         // whole crate, just treat it as a reference to whatever the implementor is.
3093                                         if with_ref_lifetime {
3094                                                 // Hope we're being printed in function generics and let rustc derive the
3095                                                 // type.
3096                                                 write!(w, "_").unwrap();
3097                                         } else {
3098                                                 write!(w, "&crate::{}", trait_impls[0]).unwrap();
3099                                         }
3100                                         return true;
3101                                 }
3102                         }
3103                         false
3104                 }
3105         }
3106         fn write_c_type_intern<W: std::io::Write>(&self, w: &mut W, t: &syn::Type, generics: Option<&GenericTypes>, is_ref: bool, is_mut: bool, ptr_for_ref: bool, with_ref_lifetime: bool, c_ty: bool) -> bool {
3107                 match generics.resolve_type(t) {
3108                         syn::Type::Path(p) => {
3109                                 if p.qself.is_some() {
3110                                         return false;
3111                                 }
3112                                 if let Some(full_path) = self.maybe_resolve_path(&p.path, generics) {
3113                                         if self.is_known_container(&full_path, is_ref) || self.is_path_transparent_container(&p.path, generics, is_ref) {
3114                                                 return self.write_c_mangled_container_path(w, Self::path_to_generic_args(&p.path), generics, &full_path, is_ref, is_mut, ptr_for_ref);
3115                                         }
3116                                         if let Some(aliased_type) = self.crate_types.type_aliases.get(&full_path).cloned() {
3117                                                 return self.write_c_type_intern(w, &aliased_type, None, is_ref, is_mut, ptr_for_ref, with_ref_lifetime, c_ty);
3118                                         }
3119                                 }
3120                                 self.write_c_path_intern(w, &p.path, generics, is_ref, is_mut, ptr_for_ref, with_ref_lifetime, c_ty)
3121                         },
3122                         syn::Type::Reference(r) => {
3123                                 self.write_c_type_intern(w, &*r.elem, generics, true, r.mutability.is_some(), ptr_for_ref, with_ref_lifetime, c_ty)
3124                         },
3125                         syn::Type::Array(a) => {
3126                                 if is_ref && is_mut {
3127                                         write!(w, "*mut [").unwrap();
3128                                         if !self.write_c_type_intern(w, &a.elem, generics, false, false, ptr_for_ref, with_ref_lifetime, c_ty) { return false; }
3129                                 } else if is_ref {
3130                                         write!(w, "*const [").unwrap();
3131                                         if !self.write_c_type_intern(w, &a.elem, generics, false, false, ptr_for_ref, with_ref_lifetime, c_ty) { return false; }
3132                                 }
3133                                 if let syn::Expr::Lit(l) = &a.len {
3134                                         if let syn::Lit::Int(i) = &l.lit {
3135                                                 let mut inner_ty = Vec::new();
3136                                                 if !self.write_c_type_intern(&mut inner_ty, &*a.elem, generics, false, false, ptr_for_ref, false, c_ty) { return false; }
3137                                                 let inner_ty_str = String::from_utf8(inner_ty).unwrap();
3138                                                 if !is_ref {
3139                                                         if let Some(ty) = self.c_type_from_path(&format!("[{}; {}]", inner_ty_str, i.base10_digits()), false, ptr_for_ref) {
3140                                                                 write!(w, "{}", ty).unwrap();
3141                                                                 true
3142                                                         } else { false }
3143                                                 } else {
3144                                                         write!(w, "; {}]", i).unwrap();
3145                                                         true
3146                                                 }
3147                                         } else { false }
3148                                 } else { false }
3149                         }
3150                         syn::Type::Slice(s) => {
3151                                 if !is_ref || is_mut { return false; }
3152                                 if let syn::Type::Path(p) = &*s.elem {
3153                                         let resolved = self.resolve_path(&p.path, generics);
3154                                         if self.is_primitive(&resolved) {
3155                                                 write!(w, "{}::{}slice", Self::container_templ_path(), resolved).unwrap();
3156                                                 true
3157                                         } else {
3158                                                 let mut inner_c_ty = Vec::new();
3159                                                 assert!(self.write_c_path_intern(&mut inner_c_ty, &p.path, generics, true, false, ptr_for_ref, with_ref_lifetime, c_ty));
3160                                                 let inner_ty_str = String::from_utf8(inner_c_ty).unwrap();
3161                                                 if self.is_clonable(&inner_ty_str) {
3162                                                         let inner_ty_ident = inner_ty_str.rsplitn(2, "::").next().unwrap();
3163                                                         let mangled_container = format!("CVec_{}Z", inner_ty_ident);
3164                                                         write!(w, "{}::{}", Self::generated_container_path(), mangled_container).unwrap();
3165                                                         self.check_create_container(mangled_container, "Vec", vec![&*s.elem], generics, false)
3166                                                 } else { false }
3167                                         }
3168                                 } else if let syn::Type::Reference(r) = &*s.elem {
3169                                         if let syn::Type::Path(p) = &*r.elem {
3170                                                 // Slices with "real types" inside are mapped as the equivalent non-ref Vec
3171                                                 let resolved = self.resolve_path(&p.path, generics);
3172                                                 let mangled_container = if let Some((ident, _)) = self.crate_types.opaques.get(&resolved) {
3173                                                         format!("CVec_{}Z", ident)
3174                                                 } else if let Some(en) = self.crate_types.mirrored_enums.get(&resolved) {
3175                                                         format!("CVec_{}Z", en.ident)
3176                                                 } else if let Some(id) = p.path.get_ident() {
3177                                                         format!("CVec_{}Z", id)
3178                                                 } else { return false; };
3179                                                 write!(w, "{}::{}", Self::generated_container_path(), mangled_container).unwrap();
3180                                                 self.check_create_container(mangled_container, "Vec", vec![&*r.elem], generics, false)
3181                                         } else if let syn::Type::Slice(sl2) = &*r.elem {
3182                                                 if let syn::Type::Reference(r2) = &*sl2.elem {
3183                                                         if let syn::Type::Path(p) = &*r2.elem {
3184                                                                 // Slices with slices with opaque types (with is_owned flags) are mapped as non-ref Vecs
3185                                                                 let resolved = self.resolve_path(&p.path, generics);
3186                                                                 let mangled_container = if let Some((ident, _)) = self.crate_types.opaques.get(&resolved) {
3187                                                                         format!("CVec_CVec_{}ZZ", ident)
3188                                                                 } else { return false; };
3189                                                                 write!(w, "{}::{}", Self::generated_container_path(), mangled_container).unwrap();
3190                                                                 let inner = &r2.elem;
3191                                                                 let vec_ty: syn::Type = syn::parse_quote!(Vec<#inner>);
3192                                                                 self.check_create_container(mangled_container, "Vec", vec![&vec_ty], generics, false)
3193                                                         } else { false }
3194                                                 } else { false }
3195                                         } else { false }
3196                                 } else if let syn::Type::Tuple(_) = &*s.elem {
3197                                         let mut args = syn::punctuated::Punctuated::<_, syn::token::Comma>::new();
3198                                         args.push(syn::GenericArgument::Type((*s.elem).clone()));
3199                                         let mut segments = syn::punctuated::Punctuated::new();
3200                                         segments.push(parse_quote!(Vec<#args>));
3201                                         self.write_c_type_intern(w, &syn::Type::Path(syn::TypePath { qself: None, path: syn::Path { leading_colon: None, segments } }), generics, false, is_mut, ptr_for_ref, with_ref_lifetime, c_ty)
3202                                 } else if let syn::Type::Array(a) = &*s.elem {
3203                                         if let syn::Expr::Lit(l) = &a.len {
3204                                                 if let syn::Lit::Int(i) = &l.lit {
3205                                                         let mut buf = Vec::new();
3206                                                         self.write_rust_type(&mut buf, generics, &*a.elem, false);
3207                                                         let arr_ty = String::from_utf8(buf).unwrap();
3208
3209                                                         let arr_str = format!("[{}; {}]", arr_ty, i.base10_digits());
3210                                                         let ty = self.c_type_from_path(&arr_str, false, ptr_for_ref).unwrap()
3211                                                                 .rsplitn(2, "::").next().unwrap();
3212
3213                                                         let mangled_container = format!("CVec_{}Z", ty);
3214                                                         write!(w, "{}::{}", Self::generated_container_path(), mangled_container).unwrap();
3215                                                         self.check_create_container(mangled_container, "Vec", vec![&*s.elem], generics, false)
3216                                                 } else { false }
3217                                         } else { false }
3218                                 } else { false }
3219                         },
3220                         syn::Type::Tuple(t) => {
3221                                 if t.elems.len() == 0 {
3222                                         true
3223                                 } else {
3224                                         self.write_c_mangled_container_path(w, t.elems.iter().collect(), generics,
3225                                                 &format!("{}Tuple", t.elems.len()), is_ref, is_mut, ptr_for_ref)
3226                                 }
3227                         },
3228                         _ => false,
3229                 }
3230         }
3231         pub fn write_c_type<W: std::io::Write>(&self, w: &mut W, t: &syn::Type, generics: Option<&GenericTypes>, ptr_for_ref: bool) {
3232                 assert!(self.write_c_type_intern(w, t, generics, false, false, ptr_for_ref, false, true));
3233         }
3234         pub fn write_c_type_in_generic_param<W: std::io::Write>(&self, w: &mut W, t: &syn::Type, generics: Option<&GenericTypes>, ptr_for_ref: bool) {
3235                 assert!(self.write_c_type_intern(w, t, generics, false, false, ptr_for_ref, true, false));
3236         }
3237         pub fn understood_c_path(&self, p: &syn::Path) -> bool {
3238                 self.write_c_path_intern(&mut std::io::sink(), p, None, false, false, false, false, true)
3239         }
3240         pub fn understood_c_type(&self, t: &syn::Type, generics: Option<&GenericTypes>) -> bool {
3241                 self.write_c_type_intern(&mut std::io::sink(), t, generics, false, false, false, false, true)
3242         }
3243 }