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