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