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