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

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