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