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