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

   1 use std::collections::{HashMap, HashSet};
   2 use std::fs::File;
   3 use std::io::Write;
   4 use std::hash;
   5
   6 use crate::blocks::*;
   7
   8 use proc_macro2::{TokenTree, Span};
   9
  10 // The following utils are used purely to build our known types maps - they break down all the
  11 // types we need to resolve to include the given object, and no more.
  12
  13 pub fn first_seg_self<'a>(t: &'a syn::Type) -> Option<impl Iterator<Item=&syn::PathSegment> + 'a> {
  14         match t {
  15                 syn::Type::Path(p) => {
  16                         if p.qself.is_some() || p.path.leading_colon.is_some() {
  17                                 return None;
  18                         }
  19                         let mut segs = p.path.segments.iter();
  20                         let ty = segs.next().unwrap();
  21                         if !ty.arguments.is_empty() { return None; }
  22                         if format!("{}", ty.ident) == "Self" {
  23                                 Some(segs)
  24                         } else { None }
  25                 },
  26                 _ => None,
  27         }
  28 }
  29
  30 pub fn get_single_remaining_path_seg<'a, I: Iterator<Item=&'a syn::PathSegment>>(segs: &mut I) -> Option<&'a syn::Ident> {
  31         if let Some(ty) = segs.next() {
  32                 if !ty.arguments.is_empty() { unimplemented!(); }
  33                 if segs.next().is_some() { return None; }
  34                 Some(&ty.ident)
  35         } else { None }
  36 }
  37
  38 pub fn single_ident_generic_path_to_ident(p: &syn::Path) -> Option<&syn::Ident> {
  39         if p.segments.len() == 1 {
  40                 Some(&p.segments.iter().next().unwrap().ident)
  41         } else { None }
  42 }
  43
  44 pub fn path_matches_nongeneric(p: &syn::Path, exp: &[&str]) -> bool {
  45         if p.segments.len() != exp.len() { return false; }
  46         for (seg, e) in p.segments.iter().zip(exp.iter()) {
  47                 if seg.arguments != syn::PathArguments::None { return false; }
  48                 if &format!("{}", seg.ident) != *e { return false; }
  49         }
  50         true
  51 }
  52
  53 #[derive(Debug, PartialEq)]
  54 pub enum ExportStatus {
  55         Export,
  56         NoExport,
  57         TestOnly,
  58 }
  59 /// Gets the ExportStatus of an object (struct, fn, etc) given its attributes.
  60 pub fn export_status(attrs: &[syn::Attribute]) -> ExportStatus {
  61         for attr in attrs.iter() {
  62                 let tokens_clone = attr.tokens.clone();
  63                 let mut token_iter = tokens_clone.into_iter();
  64                 if let Some(token) = token_iter.next() {
  65                         match token {
  66                                 TokenTree::Punct(c) if c.as_char() == '=' => {
  67                                         // Really not sure where syn gets '=' from here -
  68                                         // it somehow represents '///' or '//!'
  69                                 },
  70                                 TokenTree::Group(g) => {
  71                                         if format!("{}", single_ident_generic_path_to_ident(&attr.path).unwrap()) == "cfg" {
  72                                                 let mut iter = g.stream().into_iter();
  73                                                 if let TokenTree::Ident(i) = iter.next().unwrap() {
  74                                                         if i == "any" {
  75                                                                 // #[cfg(any(test, feature = ""))]
  76                                                                 if let TokenTree::Group(g) = iter.next().unwrap() {
  77                                                                         if let TokenTree::Ident(i) = g.stream().into_iter().next().unwrap() {
  78                                                                                 if i == "test" || i == "feature" {
  79                                                                                         // If its cfg(feature(...)) we assume its test-only
  80                                                                                         return ExportStatus::TestOnly;
  81                                                                                 }
  82                                                                         }
  83                                                                 }
  84                                                         } else if i == "test" || i == "feature" {
  85                                                                 // If its cfg(feature(...)) we assume its test-only
  86                                                                 return ExportStatus::TestOnly;
  87                                                         }
  88                                                 }
  89                                         }
  90                                         continue; // eg #[derive()]
  91                                 },
  92                                 _ => unimplemented!(),
  93                         }
  94                 } else { continue; }
  95                 match token_iter.next().unwrap() {
  96                         TokenTree::Literal(lit) => {
  97                                 let line = format!("{}", lit);
  98                                 if line.contains("(C-not exported)") {
  99                                         return ExportStatus::NoExport;
 100                                 }
 101                         },
 102                         _ => unimplemented!(),
 103                 }
 104         }
 105         ExportStatus::Export
 106 }
 107
 108 pub fn assert_simple_bound(bound: &syn::TraitBound) {
 109         if bound.paren_token.is_some() || bound.lifetimes.is_some() { unimplemented!(); }
 110         if let syn::TraitBoundModifier::Maybe(_) = bound.modifier { unimplemented!(); }
 111 }
 112
 113 /// Returns true if the enum will be mapped as an opaue (ie struct with a pointer to the underlying
 114 /// type), otherwise it is mapped into a transparent, C-compatible version of itself.
 115 pub fn is_enum_opaque(e: &syn::ItemEnum) -> bool {
 116         for var in e.variants.iter() {
 117                 if let syn::Fields::Named(fields) = &var.fields {
 118                         for field in fields.named.iter() {
 119                                 match export_status(&field.attrs) {
 120                                         ExportStatus::Export|ExportStatus::TestOnly => {},
 121                                         ExportStatus::NoExport => return true,
 122                                 }
 123                         }
 124                 } else if let syn::Fields::Unnamed(fields) = &var.fields {
 125                         for field in fields.unnamed.iter() {
 126                                 match export_status(&field.attrs) {
 127                                         ExportStatus::Export|ExportStatus::TestOnly => {},
 128                                         ExportStatus::NoExport => return true,
 129                                 }
 130                         }
 131                 }
 132         }
 133         false
 134 }
 135
 136 /// A stack of sets of generic resolutions.
 137 ///
 138 /// This tracks the template parameters for a function, struct, or trait, allowing resolution into
 139 /// a concrete type. By pushing a new context onto the stack, this can track a function's template
 140 /// parameters inside of a generic struct or trait.
 141 ///
 142 /// It maps both direct types as well as Deref<Target = X>, mapping them via the provided
 143 /// TypeResolver's resolve_path function (ie traits map to the concrete jump table, structs to the
 144 /// concrete C container struct, etc).
 145 pub struct GenericTypes<'a> {
 146         typed_generics: Vec<HashMap<&'a syn::Ident, (String, Option<&'a syn::Path>)>>,
 147 }
 148 impl<'a> GenericTypes<'a> {
 149         pub fn new() -> Self {
 150                 Self { typed_generics: vec![HashMap::new()], }
 151         }
 152
 153         /// push a new context onto the stack, allowing for a new set of generics to be learned which
 154         /// will override any lower contexts, but which will still fall back to resoltion via lower
 155         /// contexts.
 156         pub fn push_ctx(&mut self) {
 157                 self.typed_generics.push(HashMap::new());
 158         }
 159         /// pop the latest context off the stack.
 160         pub fn pop_ctx(&mut self) {
 161                 self.typed_generics.pop();
 162         }
 163
 164         /// Learn the generics in generics in the current context, given a TypeResolver.
 165         pub fn learn_generics<'b, 'c>(&mut self, generics: &'a syn::Generics, types: &'b TypeResolver<'a, 'c>) -> bool {
 166                 // First learn simple generics...
 167                 for generic in generics.params.iter() {
 168                         match generic {
 169                                 syn::GenericParam::Type(type_param) => {
 170                                         let mut non_lifetimes_processed = false;
 171                                         for bound in type_param.bounds.iter() {
 172                                                 if let syn::TypeParamBound::Trait(trait_bound) = bound {
 173                                                         if let Some(ident) = single_ident_generic_path_to_ident(&trait_bound.path) {
 174                                                                 match &format!("{}", ident) as &str { "Send" => continue, "Sync" => continue, _ => {} }
 175                                                         }
 176                                                         if path_matches_nongeneric(&trait_bound.path, &["core", "clone", "Clone"]) { continue; }
 177
 178                                                         assert_simple_bound(&trait_bound);
 179                                                         if let Some(mut path) = types.maybe_resolve_path(&trait_bound.path, None) {
 180                                                                 if types.skip_path(&path) { continue; }
 181                                                                 if non_lifetimes_processed { return false; }
 182                                                                 non_lifetimes_processed = true;
 183                                                                 let new_ident = if path != "std::ops::Deref" {
 184                                                                         path = "crate::".to_string() + &path;
 185                                                                         Some(&trait_bound.path)
 186                                                                 } else { None };
 187                                                                 self.typed_generics.last_mut().unwrap().insert(&type_param.ident, (path, new_ident));
 188                                                         } else { return false; }
 189                                                 }
 190                                         }
 191                                 },
 192                                 _ => {},
 193                         }
 194                 }
 195                 // Then find generics where we are required to pass a Deref<Target=X> and pretend its just X.
 196                 if let Some(wh) = &generics.where_clause {
 197                         for pred in wh.predicates.iter() {
 198                                 if let syn::WherePredicate::Type(t) = pred {
 199                                         if let syn::Type::Path(p) = &t.bounded_ty {
 200                                                 if p.qself.is_some() { return false; }
 201                                                 if p.path.leading_colon.is_some() { return false; }
 202                                                 let mut p_iter = p.path.segments.iter();
 203                                                 if let Some(gen) = self.typed_generics.last_mut().unwrap().get_mut(&p_iter.next().unwrap().ident) {
 204                                                         if gen.0 != "std::ops::Deref" { return false; }
 205                                                         if &format!("{}", p_iter.next().unwrap().ident) != "Target" { return false; }
 206
 207                                                         let mut non_lifetimes_processed = false;
 208                                                         for bound in t.bounds.iter() {
 209                                                                 if let syn::TypeParamBound::Trait(trait_bound) = bound {
 210                                                                         if non_lifetimes_processed { return false; }
 211                                                                         non_lifetimes_processed = true;
 212                                                                         assert_simple_bound(&trait_bound);
 213                                                                         *gen = ("crate::".to_string() + &types.resolve_path(&trait_bound.path, None),
 214                                                                                 Some(&trait_bound.path));
 215                                                                 }
 216                                                         }
 217                                                 } else { return false; }
 218                                         } else { return false; }
 219                                 }
 220                         }
 221                 }
 222                 for (_, (_, ident)) in self.typed_generics.last().unwrap().iter() {
 223                         if ident.is_none() { return false; }
 224                 }
 225                 true
 226         }
 227
 228         /// Learn the associated types from the trait in the current context.
 229         pub fn learn_associated_types<'b, 'c>(&mut self, t: &'a syn::ItemTrait, types: &'b TypeResolver<'a, 'c>) {
 230                 for item in t.items.iter() {
 231                         match item {
 232                                 &syn::TraitItem::Type(ref t) => {
 233                                         if t.default.is_some() || t.generics.lt_token.is_some() { unimplemented!(); }
 234                                         let mut bounds_iter = t.bounds.iter();
 235                                         match bounds_iter.next().unwrap() {
 236                                                 syn::TypeParamBound::Trait(tr) => {
 237                                                         assert_simple_bound(&tr);
 238                                                         if let Some(mut path) = types.maybe_resolve_path(&tr.path, None) {
 239                                                                 if types.skip_path(&path) { continue; }
 240                                                                 // In general we handle Deref<Target=X> as if it were just X (and
 241                                                                 // implement Deref<Target=Self> for relevant types). We don't
 242                                                                 // bother to implement it for associated types, however, so we just
 243                                                                 // ignore such bounds.
 244                                                                 let new_ident = if path != "std::ops::Deref" {
 245                                                                         path = "crate::".to_string() + &path;
 246                                                                         Some(&tr.path)
 247                                                                 } else { None };
 248                                                                 self.typed_generics.last_mut().unwrap().insert(&t.ident, (path, new_ident));
 249                                                         } else { unimplemented!(); }
 250                                                 },
 251                                                 _ => unimplemented!(),
 252                                         }
 253                                         if bounds_iter.next().is_some() { unimplemented!(); }
 254                                 },
 255                                 _ => {},
 256                         }
 257                 }
 258         }
 259
 260         /// Attempt to resolve an Ident as a generic parameter and return the full path.
 261         pub fn maybe_resolve_ident<'b>(&'b self, ident: &syn::Ident) -> Option<&'b String> {
 262                 for gen in self.typed_generics.iter().rev() {
 263                         if let Some(res) = gen.get(ident).map(|(a, _)| a) {
 264                                 return Some(res);
 265                         }
 266                 }
 267                 None
 268         }
 269         /// Attempt to resolve a Path as a generic parameter and return the full path. as both a string
 270         /// and syn::Path.
 271         pub fn maybe_resolve_path<'b>(&'b self, path: &syn::Path) -> Option<(&'b String, &'a syn::Path)> {
 272                 if let Some(ident) = path.get_ident() {
 273                         for gen in self.typed_generics.iter().rev() {
 274                                 if let Some(res) = gen.get(ident).map(|(a, b)| (a, b.unwrap())) {
 275                                         return Some(res);
 276                                 }
 277                         }
 278                 } else {
 279                         // Associated types are usually specified as "Self::Generic", so we check for that
 280                         // explicitly here.
 281                         let mut it = path.segments.iter();
 282                         if path.segments.len() == 2 && format!("{}", it.next().unwrap().ident) == "Self" {
 283                                 let ident = &it.next().unwrap().ident;
 284                                 for gen in self.typed_generics.iter().rev() {
 285                                         if let Some(res) = gen.get(ident).map(|(a, b)| (a, b.unwrap())) {
 286                                                 return Some(res);
 287                                         }
 288                                 }
 289                         }
 290                 }
 291                 None
 292         }
 293 }
 294
 295 #[derive(Clone, PartialEq)]
 296 // The type of declaration and the object itself
 297 pub enum DeclType<'a> {
 298         MirroredEnum,
 299         Trait(&'a syn::ItemTrait),
 300         StructImported,
 301         StructIgnored,
 302         EnumIgnored,
 303 }
 304
 305 pub struct ImportResolver<'mod_lifetime, 'crate_lft: 'mod_lifetime> {
 306         module_path: &'mod_lifetime str,
 307         imports: HashMap<syn::Ident, (String, syn::Path)>,
 308         declared: HashMap<syn::Ident, DeclType<'crate_lft>>,
 309         priv_modules: HashSet<syn::Ident>,
 310 }
 311 impl<'mod_lifetime, 'crate_lft: 'mod_lifetime> ImportResolver<'mod_lifetime, 'crate_lft> {
 312         fn process_use_intern(imports: &mut HashMap<syn::Ident, (String, syn::Path)>, u: &syn::UseTree, partial_path: &str, mut path: syn::punctuated::Punctuated<syn::PathSegment, syn::token::Colon2>) {
 313                 match u {
 314                         syn::UseTree::Path(p) => {
 315                                 let new_path = format!("{}{}::", partial_path, p.ident);
 316                                 path.push(syn::PathSegment { ident: p.ident.clone(), arguments: syn::PathArguments::None });
 317                                 Self::process_use_intern(imports, &p.tree, &new_path, path);
 318                         },
 319                         syn::UseTree::Name(n) => {
 320                                 let full_path = format!("{}{}", partial_path, n.ident);
 321                                 path.push(syn::PathSegment { ident: n.ident.clone(), arguments: syn::PathArguments::None });
 322                                 imports.insert(n.ident.clone(), (full_path, syn::Path { leading_colon: Some(syn::Token![::](Span::call_site())), segments: path }));
 323                         },
 324                         syn::UseTree::Group(g) => {
 325                                 for i in g.items.iter() {
 326                                         Self::process_use_intern(imports, i, partial_path, path.clone());
 327                                 }
 328                         },
 329                         syn::UseTree::Rename(r) => {
 330                                 let full_path = format!("{}{}", partial_path, r.ident);
 331                                 path.push(syn::PathSegment { ident: r.ident.clone(), arguments: syn::PathArguments::None });
 332                                 imports.insert(r.rename.clone(), (full_path, syn::Path { leading_colon: Some(syn::Token![::](Span::call_site())), segments: path }));
 333                         },
 334                         syn::UseTree::Glob(_) => {
 335                                 eprintln!("Ignoring * use for {} - this may result in resolution failures", partial_path);
 336                         },
 337                 }
 338         }
 339
 340         fn process_use(imports: &mut HashMap<syn::Ident, (String, syn::Path)>, u: &syn::ItemUse) {
 341                 if let syn::Visibility::Public(_) = u.vis {
 342                         // We actually only use these for #[cfg(fuzztarget)]
 343                         eprintln!("Ignoring pub(use) tree!");
 344                         return;
 345                 }
 346                 if u.leading_colon.is_some() { eprintln!("Ignoring leading-colon use!"); return; }
 347                 Self::process_use_intern(imports, &u.tree, "", syn::punctuated::Punctuated::new());
 348         }
 349
 350         fn insert_primitive(imports: &mut HashMap<syn::Ident, (String, syn::Path)>, id: &str) {
 351                 let ident = syn::Ident::new(id, Span::call_site());
 352                 let mut path = syn::punctuated::Punctuated::new();
 353                 path.push(syn::PathSegment { ident: ident.clone(), arguments: syn::PathArguments::None });
 354                 imports.insert(ident, (id.to_owned(), syn::Path { leading_colon: Some(syn::Token![::](Span::call_site())), segments: path }));
 355         }
 356
 357         pub fn new(module_path: &'mod_lifetime str, contents: &'crate_lft [syn::Item]) -> Self {
 358                 let mut imports = HashMap::new();
 359                 // Add primitives to the "imports" list:
 360                 Self::insert_primitive(&mut imports, "bool");
 361                 Self::insert_primitive(&mut imports, "u64");
 362                 Self::insert_primitive(&mut imports, "u32");
 363                 Self::insert_primitive(&mut imports, "u16");
 364                 Self::insert_primitive(&mut imports, "u8");
 365                 Self::insert_primitive(&mut imports, "usize");
 366                 Self::insert_primitive(&mut imports, "str");
 367                 Self::insert_primitive(&mut imports, "String");
 368
 369                 // These are here to allow us to print native Rust types in trait fn impls even if we don't
 370                 // have C mappings:
 371                 Self::insert_primitive(&mut imports, "Result");
 372                 Self::insert_primitive(&mut imports, "Vec");
 373                 Self::insert_primitive(&mut imports, "Option");
 374
 375                 let mut declared = HashMap::new();
 376                 let mut priv_modules = HashSet::new();
 377
 378                 for item in contents.iter() {
 379                         match item {
 380                                 syn::Item::Use(u) => Self::process_use(&mut imports, &u),
 381                                 syn::Item::Struct(s) => {
 382                                         if let syn::Visibility::Public(_) = s.vis {
 383                                                 match export_status(&s.attrs) {
 384                                                         ExportStatus::Export => { declared.insert(s.ident.clone(), DeclType::StructImported); },
 385                                                         ExportStatus::NoExport => { declared.insert(s.ident.clone(), DeclType::StructIgnored); },
 386                                                         ExportStatus::TestOnly => continue,
 387                                                 }
 388                                         }
 389                                 },
 390                                 syn::Item::Type(t) if export_status(&t.attrs) == ExportStatus::Export => {
 391                                         if let syn::Visibility::Public(_) = t.vis {
 392                                                 let mut process_alias = true;
 393                                                 for tok in t.generics.params.iter() {
 394                                                         if let syn::GenericParam::Lifetime(_) = tok {}
 395                                                         else { process_alias = false; }
 396                                                 }
 397                                                 if process_alias {
 398                                                         match &*t.ty {
 399                                                                 syn::Type::Path(_) => { declared.insert(t.ident.clone(), DeclType::StructImported); },
 400                                                                 _ => {},
 401                                                         }
 402                                                 }
 403                                         }
 404                                 },
 405                                 syn::Item::Enum(e) => {
 406                                         if let syn::Visibility::Public(_) = e.vis {
 407                                                 match export_status(&e.attrs) {
 408                                                         ExportStatus::Export if is_enum_opaque(e) => { declared.insert(e.ident.clone(), DeclType::EnumIgnored); },
 409                                                         ExportStatus::Export => { declared.insert(e.ident.clone(), DeclType::MirroredEnum); },
 410                                                         _ => continue,
 411                                                 }
 412                                         }
 413                                 },
 414                                 syn::Item::Trait(t) if export_status(&t.attrs) == ExportStatus::Export => {
 415                                         if let syn::Visibility::Public(_) = t.vis {
 416                                                 declared.insert(t.ident.clone(), DeclType::Trait(t));
 417                                         }
 418                                 },
 419                                 syn::Item::Mod(m) => {
 420                                         priv_modules.insert(m.ident.clone());
 421                                 },
 422                                 _ => {},
 423                         }
 424                 }
 425
 426                 Self { module_path, imports, declared, priv_modules }
 427         }
 428
 429         pub fn get_declared_type(&self, ident: &syn::Ident) -> Option<&DeclType<'crate_lft>> {
 430                 self.declared.get(ident)
 431         }
 432
 433         pub fn maybe_resolve_declared(&self, id: &syn::Ident) -> Option<&DeclType<'crate_lft>> {
 434                 self.declared.get(id)
 435         }
 436
 437         pub fn maybe_resolve_ident(&self, id: &syn::Ident) -> Option<String> {
 438                 if let Some((imp, _)) = self.imports.get(id) {
 439                         Some(imp.clone())
 440                 } else if self.declared.get(id).is_some() {
 441                         Some(self.module_path.to_string() + "::" + &format!("{}", id))
 442                 } else { None }
 443         }
 444
 445         pub fn maybe_resolve_non_ignored_ident(&self, id: &syn::Ident) -> Option<String> {
 446                 if let Some((imp, _)) = self.imports.get(id) {
 447                         Some(imp.clone())
 448                 } else if let Some(decl_type) = self.declared.get(id) {
 449                         match decl_type {
 450                                 DeclType::StructIgnored => None,
 451                                 _ => Some(self.module_path.to_string() + "::" + &format!("{}", id)),
 452                         }
 453                 } else { None }
 454         }
 455
 456         pub fn maybe_resolve_path(&self, p_arg: &syn::Path, generics: Option<&GenericTypes>) -> Option<String> {
 457                 let p = if let Some(gen_types) = generics {
 458                         if let Some((_, synpath)) = gen_types.maybe_resolve_path(p_arg) {
 459                                 synpath
 460                         } else { p_arg }
 461                 } else { p_arg };
 462
 463                 if p.leading_colon.is_some() {
 464                         Some(p.segments.iter().enumerate().map(|(idx, seg)| {
 465                                 format!("{}{}", if idx == 0 { "" } else { "::" }, seg.ident)
 466                         }).collect())
 467                 } else if let Some(id) = p.get_ident() {
 468                         self.maybe_resolve_ident(id)
 469                 } else {
 470                         if p.segments.len() == 1 {
 471                                 let seg = p.segments.iter().next().unwrap();
 472                                 return self.maybe_resolve_ident(&seg.ident);
 473                         }
 474                         let mut seg_iter = p.segments.iter();
 475                         let first_seg = seg_iter.next().unwrap();
 476                         let remaining: String = seg_iter.map(|seg| {
 477                                 format!("::{}", seg.ident)
 478                         }).collect();
 479                         if let Some((imp, _)) = self.imports.get(&first_seg.ident) {
 480                                 if remaining != "" {
 481                                         Some(imp.clone() + &remaining)
 482                                 } else {
 483                                         Some(imp.clone())
 484                                 }
 485                         } else if let Some(_) = self.priv_modules.get(&first_seg.ident) {
 486                                 Some(format!("{}::{}{}", self.module_path, first_seg.ident, remaining))
 487                         } else { None }
 488                 }
 489         }
 490
 491         /// Map all the Paths in a Type into absolute paths given a set of imports (generated via process_use_intern)
 492         pub fn resolve_imported_refs(&self, mut ty: syn::Type) -> syn::Type {
 493                 match &mut ty {
 494                         syn::Type::Path(p) => {
 495                                 if let Some(ident) = p.path.get_ident() {
 496                                         if let Some((_, newpath)) = self.imports.get(ident) {
 497                                                 p.path = newpath.clone();
 498                                         }
 499                                 } else { unimplemented!(); }
 500                         },
 501                         syn::Type::Reference(r) => {
 502                                 r.elem = Box::new(self.resolve_imported_refs((*r.elem).clone()));
 503                         },
 504                         syn::Type::Slice(s) => {
 505                                 s.elem = Box::new(self.resolve_imported_refs((*s.elem).clone()));
 506                         },
 507                         syn::Type::Tuple(t) => {
 508                                 for e in t.elems.iter_mut() {
 509                                         *e = self.resolve_imported_refs(e.clone());
 510                                 }
 511                         },
 512                         _ => unimplemented!(),
 513                 }
 514                 ty
 515         }
 516 }
 517
 518 // templates_defined is walked to write the C++ header, so if we use the default hashing it get
 519 // reordered on each genbindings run. Instead, we use SipHasher (which defaults to 0-keys) so that
 520 // the sorting is stable across runs. It is deprecated, but the "replacement" doesn't actually
 521 // accomplish the same goals, so we just ignore it.
 522 #[allow(deprecated)]
 523 pub type NonRandomHash = hash::BuildHasherDefault<hash::SipHasher>;
 524
 525 /// Top-level struct tracking everything which has been defined while walking the crate.
 526 pub struct CrateTypes<'a> {
 527         /// This may contain structs or enums, but only when either is mapped as
 528         /// struct X { inner: *mut originalX, .. }
 529         pub opaques: HashMap<String, &'a syn::Ident>,
 530         /// Enums which are mapped as C enums with conversion functions
 531         pub mirrored_enums: HashMap<String, &'a syn::ItemEnum>,
 532         /// Traits which are mapped as a pointer + jump table
 533         pub traits: HashMap<String, &'a syn::ItemTrait>,
 534         /// Aliases from paths to some other Type
 535         pub type_aliases: HashMap<String, syn::Type>,
 536         /// Value is an alias to Key (maybe with some generics)
 537         pub reverse_alias_map: HashMap<String, Vec<(syn::Path, syn::PathArguments)>>,
 538         /// Template continer types defined, map from mangled type name -> whether a destructor fn
 539         /// exists.
 540         ///
 541         /// This is used at the end of processing to make C++ wrapper classes
 542         pub templates_defined: HashMap<String, bool, NonRandomHash>,
 543         /// The output file for any created template container types, written to as we find new
 544         /// template containers which need to be defined.
 545         pub template_file: &'a mut File,
 546         /// Set of containers which are clonable
 547         pub clonable_types: HashSet<String>,
 548         /// Key impls Value
 549         pub trait_impls: HashMap<String, Vec<String>>,
 550 }
 551
 552 /// A struct which tracks resolving rust types into C-mapped equivalents, exists for one specific
 553 /// module but contains a reference to the overall CrateTypes tracking.
 554 pub struct TypeResolver<'mod_lifetime, 'crate_lft: 'mod_lifetime> {
 555         pub orig_crate: &'mod_lifetime str,
 556         pub module_path: &'mod_lifetime str,
 557         pub crate_types: &'mod_lifetime mut CrateTypes<'crate_lft>,
 558         types: ImportResolver<'mod_lifetime, 'crate_lft>,
 559 }
 560
 561 /// Returned by write_empty_rust_val_check_suffix to indicate what type of dereferencing needs to
 562 /// happen to get the inner value of a generic.
 563 enum EmptyValExpectedTy {
 564         /// A type which has a flag for being empty (eg an array where we treat all-0s as empty).
 565         NonPointer,
 566         /// A pointer that we want to dereference and move out of.
 567         OwnedPointer,
 568         /// A pointer which we want to convert to a reference.
 569         ReferenceAsPointer,
 570 }
 571
 572 impl<'a, 'c: 'a> TypeResolver<'a, 'c> {
 573         pub fn new(orig_crate: &'a str, module_path: &'a str, types: ImportResolver<'a, 'c>, crate_types: &'a mut CrateTypes<'c>) -> Self {
 574                 Self { orig_crate, module_path, types, crate_types }
 575         }
 576
 577         // *************************************************
 578         // *** Well know type and conversion definitions ***
 579         // *************************************************
 580
 581         /// Returns true we if can just skip passing this to C entirely
 582         fn skip_path(&self, full_path: &str) -> bool {
 583                 full_path == "bitcoin::secp256k1::Secp256k1" ||
 584                 full_path == "bitcoin::secp256k1::Signing" ||
 585                 full_path == "bitcoin::secp256k1::Verification"
 586         }
 587         /// Returns true we if can just skip passing this to C entirely
 588         fn no_arg_path_to_rust(&self, full_path: &str) -> &str {
 589                 if full_path == "bitcoin::secp256k1::Secp256k1" {
 590                         "secp256k1::SECP256K1"
 591                 } else { unimplemented!(); }
 592         }
 593
 594         /// Returns true if the object is a primitive and is mapped as-is with no conversion
 595         /// whatsoever.
 596         pub fn is_primitive(&self, full_path: &str) -> bool {
 597                 match full_path {
 598                         "bool" => true,
 599                         "u64" => true,
 600                         "u32" => true,
 601                         "u16" => true,
 602                         "u8" => true,
 603                         "usize" => true,
 604                         _ => false,
 605                 }
 606         }
 607         pub fn is_clonable(&self, ty: &str) -> bool {
 608                 if self.crate_types.clonable_types.contains(ty) { return true; }
 609                 if self.is_primitive(ty) { return true; }
 610                 match ty {
 611                         "()" => true,
 612                         "crate::c_types::Signature" => true,
 613                         "crate::c_types::TxOut" => true,
 614                         _ => false,
 615                 }
 616         }
 617         /// Gets the C-mapped type for types which are outside of the crate, or which are manually
 618         /// ignored by for some reason need mapping anyway.
 619         fn c_type_from_path<'b>(&self, full_path: &'b str, is_ref: bool, _ptr_for_ref: bool) -> Option<&'b str> {
 620                 if self.is_primitive(full_path) {
 621                         return Some(full_path);
 622                 }
 623                 match full_path {
 624                         "Result" => Some("crate::c_types::derived::CResult"),
 625                         "Vec" if !is_ref => Some("crate::c_types::derived::CVec"),
 626                         "Option" => Some(""),
 627
 628                         // Note that no !is_ref types can map to an array because Rust and C's call semantics
 629                         // for arrays are different (https://github.com/eqrion/cbindgen/issues/528)
 630
 631                         "[u8; 32]" if !is_ref => Some("crate::c_types::ThirtyTwoBytes"),
 632                         "[u8; 16]" if !is_ref => Some("crate::c_types::SixteenBytes"),
 633                         "[u8; 10]" if !is_ref => Some("crate::c_types::TenBytes"),
 634                         "[u8; 4]" if !is_ref => Some("crate::c_types::FourBytes"),
 635                         "[u8; 3]" if !is_ref => Some("crate::c_types::ThreeBytes"), // Used for RGB values
 636
 637                         "str" if is_ref => Some("crate::c_types::Str"),
 638                         "String" if !is_ref => Some("crate::c_types::derived::CVec_u8Z"),
 639                         "String" if is_ref => Some("crate::c_types::Str"),
 640
 641                         "std::time::Duration" => Some("u64"),
 642
 643                         "bitcoin::secp256k1::key::PublicKey" => Some("crate::c_types::PublicKey"),
 644                         "bitcoin::secp256k1::Signature" => Some("crate::c_types::Signature"),
 645                         "bitcoin::secp256k1::key::SecretKey" if is_ref  => Some("*const [u8; 32]"),
 646                         "bitcoin::secp256k1::key::SecretKey" if !is_ref => Some("crate::c_types::SecretKey"),
 647                         "bitcoin::secp256k1::Error" if !is_ref => Some("crate::c_types::Secp256k1Error"),
 648                         "bitcoin::blockdata::script::Script" if is_ref => Some("crate::c_types::u8slice"),
 649                         "bitcoin::blockdata::script::Script" if !is_ref => Some("crate::c_types::derived::CVec_u8Z"),
 650                         "bitcoin::blockdata::transaction::OutPoint" => Some("crate::chain::transaction::OutPoint"),
 651                         "bitcoin::blockdata::transaction::Transaction" => Some("crate::c_types::Transaction"),
 652                         "bitcoin::blockdata::transaction::TxOut" if !is_ref => Some("crate::c_types::TxOut"),
 653                         "bitcoin::network::constants::Network" => Some("crate::bitcoin::network::Network"),
 654                         "bitcoin::blockdata::block::BlockHeader" if is_ref  => Some("*const [u8; 80]"),
 655                         "bitcoin::blockdata::block::Block" if is_ref  => Some("crate::c_types::u8slice"),
 656
 657                         // Newtypes that we just expose in their original form.
 658                         "bitcoin::hash_types::Txid" if is_ref  => Some("*const [u8; 32]"),
 659                         "bitcoin::hash_types::Txid" if !is_ref => Some("crate::c_types::ThirtyTwoBytes"),
 660                         "bitcoin::hash_types::BlockHash" if is_ref  => Some("*const [u8; 32]"),
 661                         "bitcoin::hash_types::BlockHash" if !is_ref => Some("crate::c_types::ThirtyTwoBytes"),
 662                         "bitcoin::secp256k1::Message" if !is_ref => Some("crate::c_types::ThirtyTwoBytes"),
 663                         "ln::channelmanager::PaymentHash" if is_ref => Some("*const [u8; 32]"),
 664                         "ln::channelmanager::PaymentHash" if !is_ref => Some("crate::c_types::ThirtyTwoBytes"),
 665                         "ln::channelmanager::PaymentPreimage" if is_ref => Some("*const [u8; 32]"),
 666                         "ln::channelmanager::PaymentPreimage" if !is_ref => Some("crate::c_types::ThirtyTwoBytes"),
 667                         "ln::channelmanager::PaymentSecret" if is_ref => Some("crate::c_types::ThirtyTwoBytes"),
 668                         "ln::channelmanager::PaymentSecret" if !is_ref => Some("crate::c_types::ThirtyTwoBytes"),
 669
 670                         // Override the default since Records contain an fmt with a lifetime:
 671                         "util::logger::Record" => Some("*const std::os::raw::c_char"),
 672
 673                         _ => None,
 674                 }
 675         }
 676
 677         fn from_c_conversion_new_var_from_path<'b>(&self, _full_path: &str, _is_ref: bool) -> Option<(&'b str, &'b str)> {
 678                 None
 679         }
 680         fn from_c_conversion_prefix_from_path<'b>(&self, full_path: &str, is_ref: bool) -> Option<String> {
 681                 if self.is_primitive(full_path) {
 682                         return Some("".to_owned());
 683                 }
 684                 match full_path {
 685                         "Vec" if !is_ref => Some("local_"),
 686                         "Result" if !is_ref => Some("local_"),
 687                         "Option" if is_ref => Some("&local_"),
 688                         "Option" => Some("local_"),
 689
 690                         "[u8; 32]" if is_ref => Some("unsafe { &*"),
 691                         "[u8; 32]" if !is_ref => Some(""),
 692                         "[u8; 16]" if !is_ref => Some(""),
 693                         "[u8; 10]" if !is_ref => Some(""),
 694                         "[u8; 4]" if !is_ref => Some(""),
 695                         "[u8; 3]" if !is_ref => Some(""),
 696
 697                         "[u8]" if is_ref => Some(""),
 698                         "[usize]" if is_ref => Some(""),
 699
 700                         "str" if is_ref => Some(""),
 701                         "String" if !is_ref => Some("String::from_utf8("),
 702                         // Note that we'll panic for String if is_ref, as we only have non-owned memory, we
 703                         // cannot create a &String.
 704
 705                         "std::time::Duration" => Some("std::time::Duration::from_secs("),
 706
 707                         "bitcoin::secp256k1::key::PublicKey" if is_ref => Some("&"),
 708                         "bitcoin::secp256k1::key::PublicKey" => Some(""),
 709                         "bitcoin::secp256k1::Signature" if is_ref => Some("&"),
 710                         "bitcoin::secp256k1::Signature" => Some(""),
 711                         "bitcoin::secp256k1::key::SecretKey" if is_ref => Some("&::bitcoin::secp256k1::key::SecretKey::from_slice(&unsafe { *"),
 712                         "bitcoin::secp256k1::key::SecretKey" if !is_ref => Some(""),
 713                         "bitcoin::blockdata::script::Script" if is_ref => Some("&::bitcoin::blockdata::script::Script::from(Vec::from("),
 714                         "bitcoin::blockdata::script::Script" if !is_ref => Some("::bitcoin::blockdata::script::Script::from("),
 715                         "bitcoin::blockdata::transaction::Transaction" if is_ref => Some("&"),
 716                         "bitcoin::blockdata::transaction::Transaction" => Some(""),
 717                         "bitcoin::blockdata::transaction::TxOut" if !is_ref => Some(""),
 718                         "bitcoin::network::constants::Network" => Some(""),
 719                         "bitcoin::blockdata::block::BlockHeader" => Some("&::bitcoin::consensus::encode::deserialize(unsafe { &*"),
 720                         "bitcoin::blockdata::block::Block" if is_ref => Some("&::bitcoin::consensus::encode::deserialize("),
 721
 722                         // Newtypes that we just expose in their original form.
 723                         "bitcoin::hash_types::Txid" if is_ref => Some("&::bitcoin::hash_types::Txid::from_slice(&unsafe { &*"),
 724                         "bitcoin::hash_types::Txid" if !is_ref => Some("::bitcoin::hash_types::Txid::from_slice(&"),
 725                         "bitcoin::hash_types::BlockHash" => Some("::bitcoin::hash_types::BlockHash::from_slice(&"),
 726                         "ln::channelmanager::PaymentHash" if !is_ref => Some("::lightning::ln::channelmanager::PaymentHash("),
 727                         "ln::channelmanager::PaymentHash" if is_ref => Some("&::lightning::ln::channelmanager::PaymentHash(unsafe { *"),
 728                         "ln::channelmanager::PaymentPreimage" if !is_ref => Some("::lightning::ln::channelmanager::PaymentPreimage("),
 729                         "ln::channelmanager::PaymentPreimage" if is_ref => Some("&::lightning::ln::channelmanager::PaymentPreimage(unsafe { *"),
 730                         "ln::channelmanager::PaymentSecret" => Some("::lightning::ln::channelmanager::PaymentSecret("),
 731
 732                         // List of traits we map (possibly during processing of other files):
 733                         "crate::util::logger::Logger" => Some(""),
 734
 735                         _ => None,
 736                 }.map(|s| s.to_owned())
 737         }
 738         fn from_c_conversion_suffix_from_path<'b>(&self, full_path: &str, is_ref: bool) -> Option<String> {
 739                 if self.is_primitive(full_path) {
 740                         return Some("".to_owned());
 741                 }
 742                 match full_path {
 743                         "Vec" if !is_ref => Some(""),
 744                         "Option" => Some(""),
 745                         "Result" if !is_ref => Some(""),
 746
 747                         "[u8; 32]" if is_ref => Some("}"),
 748                         "[u8; 32]" if !is_ref => Some(".data"),
 749                         "[u8; 16]" if !is_ref => Some(".data"),
 750                         "[u8; 10]" if !is_ref => Some(".data"),
 751                         "[u8; 4]" if !is_ref => Some(".data"),
 752                         "[u8; 3]" if !is_ref => Some(".data"),
 753
 754                         "[u8]" if is_ref => Some(".to_slice()"),
 755                         "[usize]" if is_ref => Some(".to_slice()"),
 756
 757                         "str" if is_ref => Some(".into()"),
 758                         "String" if !is_ref => Some(".into_rust()).unwrap()"),
 759
 760                         "std::time::Duration" => Some(")"),
 761
 762                         "bitcoin::secp256k1::key::PublicKey" => Some(".into_rust()"),
 763                         "bitcoin::secp256k1::Signature" => Some(".into_rust()"),
 764                         "bitcoin::secp256k1::key::SecretKey" if !is_ref => Some(".into_rust()"),
 765                         "bitcoin::secp256k1::key::SecretKey" if is_ref => Some("}[..]).unwrap()"),
 766                         "bitcoin::blockdata::script::Script" if is_ref => Some(".to_slice()))"),
 767                         "bitcoin::blockdata::script::Script" if !is_ref => Some(".into_rust())"),
 768                         "bitcoin::blockdata::transaction::Transaction" => Some(".into_bitcoin()"),
 769                         "bitcoin::blockdata::transaction::TxOut" if !is_ref => Some(".into_rust()"),
 770                         "bitcoin::network::constants::Network" => Some(".into_bitcoin()"),
 771                         "bitcoin::blockdata::block::BlockHeader" => Some(" }).unwrap()"),
 772                         "bitcoin::blockdata::block::Block" => Some(".to_slice()).unwrap()"),
 773
 774                         // Newtypes that we just expose in their original form.
 775                         "bitcoin::hash_types::Txid" if is_ref => Some(" }[..]).unwrap()"),
 776                         "bitcoin::hash_types::Txid" => Some(".data[..]).unwrap()"),
 777                         "bitcoin::hash_types::BlockHash" if !is_ref => Some(".data[..]).unwrap()"),
 778                         "ln::channelmanager::PaymentHash" if !is_ref => Some(".data)"),
 779                         "ln::channelmanager::PaymentHash" if is_ref => Some(" })"),
 780                         "ln::channelmanager::PaymentPreimage" if !is_ref => Some(".data)"),
 781                         "ln::channelmanager::PaymentPreimage" if is_ref => Some(" })"),
 782                         "ln::channelmanager::PaymentSecret" => Some(".data)"),
 783
 784                         // List of traits we map (possibly during processing of other files):
 785                         "crate::util::logger::Logger" => Some(""),
 786
 787                         _ => None,
 788                 }.map(|s| s.to_owned())
 789         }
 790
 791         fn to_c_conversion_new_var_from_path<'b>(&self, full_path: &str, is_ref: bool) -> Option<(&'b str, &'b str)> {
 792                 if self.is_primitive(full_path) {
 793                         return None;
 794                 }
 795                 match full_path {
 796                         "[u8]" if is_ref => Some(("crate::c_types::u8slice::from_slice(", ")")),
 797                         "[usize]" if is_ref => Some(("crate::c_types::usizeslice::from_slice(", ")")),
 798
 799                         "bitcoin::blockdata::transaction::Transaction" if is_ref => Some(("::bitcoin::consensus::encode::serialize(", ")")),
 800                         "bitcoin::blockdata::transaction::Transaction" if !is_ref => Some(("::bitcoin::consensus::encode::serialize(&", ")")),
 801                         "bitcoin::blockdata::block::BlockHeader" if is_ref => Some(("{ let mut s = [0u8; 80]; s[..].copy_from_slice(&::bitcoin::consensus::encode::serialize(", ")); s }")),
 802                         "bitcoin::blockdata::block::Block" if is_ref => Some(("::bitcoin::consensus::encode::serialize(", ")")),
 803                         "bitcoin::hash_types::Txid" => None,
 804
 805                         // Override the default since Records contain an fmt with a lifetime:
 806                         // TODO: We should include the other record fields
 807                         "util::logger::Record" => Some(("std::ffi::CString::new(format!(\"{}\", ", ".args)).unwrap()")),
 808                         _ => None,
 809                 }.map(|s| s.to_owned())
 810         }
 811         fn to_c_conversion_inline_prefix_from_path(&self, full_path: &str, is_ref: bool, _ptr_for_ref: bool) -> Option<String> {
 812                 if self.is_primitive(full_path) {
 813                         return Some("".to_owned());
 814                 }
 815                 match full_path {
 816                         "Result" if !is_ref => Some("local_"),
 817                         "Vec" if !is_ref => Some("local_"),
 818                         "Option" => Some("local_"),
 819
 820                         "[u8; 32]" if !is_ref => Some("crate::c_types::ThirtyTwoBytes { data: "),
 821                         "[u8; 32]" if is_ref => Some("&"),
 822                         "[u8; 16]" if !is_ref => Some("crate::c_types::SixteenBytes { data: "),
 823                         "[u8; 10]" if !is_ref => Some("crate::c_types::TenBytes { data: "),
 824                         "[u8; 4]" if !is_ref => Some("crate::c_types::FourBytes { data: "),
 825                         "[u8; 3]" if is_ref => Some("&"),
 826
 827                         "[u8]" if is_ref => Some("local_"),
 828                         "[usize]" if is_ref => Some("local_"),
 829
 830                         "str" if is_ref => Some(""),
 831                         "String" => Some(""),
 832
 833                         "std::time::Duration" => Some(""),
 834
 835                         "bitcoin::secp256k1::key::PublicKey" => Some("crate::c_types::PublicKey::from_rust(&"),
 836                         "bitcoin::secp256k1::Signature" => Some("crate::c_types::Signature::from_rust(&"),
 837                         "bitcoin::secp256k1::key::SecretKey" if is_ref  => Some(""),
 838                         "bitcoin::secp256k1::key::SecretKey" if !is_ref => Some("crate::c_types::SecretKey::from_rust("),
 839                         "bitcoin::secp256k1::Error" if !is_ref => Some("crate::c_types::Secp256k1Error::from_rust("),
 840                         "bitcoin::blockdata::script::Script" if is_ref => Some("crate::c_types::u8slice::from_slice(&"),
 841                         "bitcoin::blockdata::script::Script" if !is_ref => Some(""),
 842                         "bitcoin::blockdata::transaction::Transaction" => Some("crate::c_types::Transaction::from_vec(local_"),
 843                         "bitcoin::blockdata::transaction::OutPoint" => Some("crate::c_types::bitcoin_to_C_outpoint("),
 844                         "bitcoin::blockdata::transaction::TxOut" if !is_ref => Some("crate::c_types::TxOut::from_rust("),
 845                         "bitcoin::blockdata::block::BlockHeader" if is_ref => Some("&local_"),
 846                         "bitcoin::blockdata::block::Block" if is_ref => Some("crate::c_types::u8slice::from_slice(&local_"),
 847
 848                         "bitcoin::hash_types::Txid" if !is_ref => Some("crate::c_types::ThirtyTwoBytes { data: "),
 849
 850                         // Newtypes that we just expose in their original form.
 851                         "bitcoin::hash_types::Txid" if is_ref => Some(""),
 852                         "bitcoin::hash_types::BlockHash" if is_ref => Some(""),
 853                         "bitcoin::hash_types::BlockHash" => Some("crate::c_types::ThirtyTwoBytes { data: "),
 854                         "bitcoin::secp256k1::Message" if !is_ref => Some("crate::c_types::ThirtyTwoBytes { data: "),
 855                         "ln::channelmanager::PaymentHash" if is_ref => Some("&"),
 856                         "ln::channelmanager::PaymentHash" if !is_ref => Some("crate::c_types::ThirtyTwoBytes { data: "),
 857                         "ln::channelmanager::PaymentPreimage" if is_ref => Some("&"),
 858                         "ln::channelmanager::PaymentPreimage" => Some("crate::c_types::ThirtyTwoBytes { data: "),
 859                         "ln::channelmanager::PaymentSecret" if !is_ref => Some("crate::c_types::ThirtyTwoBytes { data: "),
 860
 861                         // Override the default since Records contain an fmt with a lifetime:
 862                         "util::logger::Record" => Some("local_"),
 863
 864                         _ => None,
 865                 }.map(|s| s.to_owned())
 866         }
 867         fn to_c_conversion_inline_suffix_from_path(&self, full_path: &str, is_ref: bool, _ptr_for_ref: bool) -> Option<String> {
 868                 if self.is_primitive(full_path) {
 869                         return Some("".to_owned());
 870                 }
 871                 match full_path {
 872                         "Result" if !is_ref => Some(""),
 873                         "Vec" if !is_ref => Some(".into()"),
 874                         "Option" => Some(""),
 875
 876                         "[u8; 32]" if !is_ref => Some(" }"),
 877                         "[u8; 32]" if is_ref => Some(""),
 878                         "[u8; 16]" if !is_ref => Some(" }"),
 879                         "[u8; 10]" if !is_ref => Some(" }"),
 880                         "[u8; 4]" if !is_ref => Some(" }"),
 881                         "[u8; 3]" if is_ref => Some(""),
 882
 883                         "[u8]" if is_ref => Some(""),
 884                         "[usize]" if is_ref => Some(""),
 885
 886                         "str" if is_ref => Some(".into()"),
 887                         "String" if !is_ref => Some(".into_bytes().into()"),
 888                         "String" if is_ref => Some(".as_str().into()"),
 889
 890                         "std::time::Duration" => Some(".as_secs()"),
 891
 892                         "bitcoin::secp256k1::key::PublicKey" => Some(")"),
 893                         "bitcoin::secp256k1::Signature" => Some(")"),
 894                         "bitcoin::secp256k1::key::SecretKey" if !is_ref => Some(")"),
 895                         "bitcoin::secp256k1::key::SecretKey" if is_ref => Some(".as_ref()"),
 896                         "bitcoin::secp256k1::Error" if !is_ref => Some(")"),
 897                         "bitcoin::blockdata::script::Script" if is_ref => Some("[..])"),
 898                         "bitcoin::blockdata::script::Script" if !is_ref => Some(".into_bytes().into()"),
 899                         "bitcoin::blockdata::transaction::Transaction" => Some(")"),
 900                         "bitcoin::blockdata::transaction::OutPoint" => Some(")"),
 901                         "bitcoin::blockdata::transaction::TxOut" if !is_ref => Some(")"),
 902                         "bitcoin::blockdata::block::BlockHeader" if is_ref => Some(""),
 903                         "bitcoin::blockdata::block::Block" if is_ref => Some(")"),
 904
 905                         "bitcoin::hash_types::Txid" if !is_ref => Some(".into_inner() }"),
 906
 907                         // Newtypes that we just expose in their original form.
 908                         "bitcoin::hash_types::Txid" if is_ref => Some(".as_inner()"),
 909                         "bitcoin::hash_types::BlockHash" if is_ref => Some(".as_inner()"),
 910                         "bitcoin::hash_types::BlockHash" => Some(".into_inner() }"),
 911                         "bitcoin::secp256k1::Message" if !is_ref => Some(".as_ref().clone() }"),
 912                         "ln::channelmanager::PaymentHash" if is_ref => Some(".0"),
 913                         "ln::channelmanager::PaymentHash" => Some(".0 }"),
 914                         "ln::channelmanager::PaymentPreimage" if is_ref => Some(".0"),
 915                         "ln::channelmanager::PaymentPreimage" => Some(".0 }"),
 916                         "ln::channelmanager::PaymentSecret" if !is_ref => Some(".0 }"),
 917
 918                         // Override the default since Records contain an fmt with a lifetime:
 919                         "util::logger::Record" => Some(".as_ptr()"),
 920
 921                         _ => None,
 922                 }.map(|s| s.to_owned())
 923         }
 924
 925         fn empty_val_check_suffix_from_path(&self, full_path: &str) -> Option<&str> {
 926                 match full_path {
 927                         "ln::channelmanager::PaymentSecret" => Some(".data == [0; 32]"),
 928                         "bitcoin::secp256k1::key::PublicKey" => Some(".is_null()"),
 929                         "bitcoin::secp256k1::Signature" => Some(".is_null()"),
 930                         _ => None
 931                 }
 932         }
 933
 934         // ****************************
 935         // *** Container Processing ***
 936         // ****************************
 937
 938         /// Returns the module path in the generated mapping crate to the containers which we generate
 939         /// when writing to CrateTypes::template_file.
 940         pub fn generated_container_path() -> &'static str {
 941                 "crate::c_types::derived"
 942         }
 943         /// Returns the module path in the generated mapping crate to the container templates, which
 944         /// are then concretized and put in the generated container path/template_file.
 945         fn container_templ_path() -> &'static str {
 946                 "crate::c_types"
 947         }
 948
 949         /// Returns true if this is a "transparent" container, ie an Option or a container which does
 950         /// not require a generated continer class.
 951         fn is_transparent_container(&self, full_path: &str, _is_ref: bool) -> bool {
 952                 full_path == "Option"
 953         }
 954         /// Returns true if this is a known, supported, non-transparent container.
 955         fn is_known_container(&self, full_path: &str, is_ref: bool) -> bool {
 956                 (full_path == "Result" && !is_ref) || (full_path == "Vec" && !is_ref) || full_path.ends_with("Tuple")
 957         }
 958         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)
 959                         // Returns prefix + Vec<(prefix, var-name-to-inline-convert)> + suffix
 960                         // expecting one element in the vec per generic type, each of which is inline-converted
 961                         -> Option<(&'b str, Vec<(String, String)>, &'b str)> {
 962                 match full_path {
 963                         "Result" if !is_ref => {
 964                                 Some(("match ",
 965                                                 vec![(" { Ok(mut o) => crate::c_types::CResultTempl::ok(".to_string(), "o".to_string()),
 966                                                         (").into(), Err(mut e) => crate::c_types::CResultTempl::err(".to_string(), "e".to_string())],
 967                                                 ").into() }"))
 968                         },
 969                         "Vec" if !is_ref => {
 970                                 Some(("Vec::new(); for mut item in ", vec![(format!(".drain(..) {{ local_{}.push(", var_name), "item".to_string())], "); }"))
 971                         },
 972                         "Slice" => {
 973                                 Some(("Vec::new(); for item in ", vec![(format!(".iter() {{ local_{}.push(", var_name), "**item".to_string())], "); }"))
 974                         },
 975                         "Option" => {
 976                                 if let Some(syn::Type::Path(p)) = single_contained {
 977                                         if self.c_type_has_inner_from_path(&self.resolve_path(&p.path, generics)) {
 978                                                 if is_ref {
 979                                                         return Some(("if ", vec![
 980                                                                 (".is_none() { std::ptr::null() } else { ".to_owned(), format!("({}.as_ref().unwrap())", var_access))
 981                                                                 ], " }"));
 982                                                 } else {
 983                                                         return Some(("if ", vec![
 984                                                                 (".is_none() { std::ptr::null_mut() } else { ".to_owned(), format!("({}.unwrap())", var_access))
 985                                                                 ], " }"));
 986                                                 }
 987                                         }
 988                                 }
 989                                 if let Some(t) = single_contained {
 990                                         let mut v = Vec::new();
 991                                         self.write_empty_rust_val(generics, &mut v, t);
 992                                         let s = String::from_utf8(v).unwrap();
 993                                         return Some(("if ", vec![
 994                                                 (format!(".is_none() {{ {} }} else {{ ", s), format!("({}.unwrap())", var_access))
 995                                                 ], " }"));
 996                                 } else { unreachable!(); }
 997                         },
 998                         _ => None,
 999                 }
1000         }
1001
1002         /// only_contained_has_inner implies that there is only one contained element in the container
1003         /// and it has an inner field (ie is an "opaque" type we've defined).
1004         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)
1005                         // Returns prefix + Vec<(prefix, var-name-to-inline-convert)> + suffix
1006                         // expecting one element in the vec per generic type, each of which is inline-converted
1007                         -> Option<(&'b str, Vec<(String, String)>, &'b str)> {
1008                 match full_path {
1009                         "Result" if !is_ref => {
1010                                 Some(("match ",
1011                                                 vec![(".result_ok { true => Ok(".to_string(), format!("(*unsafe {{ Box::from_raw(<*mut _>::take_ptr(&mut {}.contents.result)) }})", var_access)),
1012                                                      ("), false => Err(".to_string(), format!("(*unsafe {{ Box::from_raw(<*mut _>::take_ptr(&mut {}.contents.err)) }})", var_access))],
1013                                                 ")}"))
1014                         },
1015                         "Vec"|"Slice" if !is_ref => {
1016                                 Some(("Vec::new(); for mut item in ", vec![(format!(".into_rust().drain(..) {{ local_{}.push(", var_name), "item".to_string())], "); }"))
1017                         },
1018                         "Slice" if is_ref => {
1019                                 Some(("Vec::new(); for mut item in ", vec![(format!(".as_slice().iter() {{ local_{}.push(", var_name), "item".to_string())], "); }"))
1020                         },
1021                         "Option" => {
1022                                 if let Some(syn::Type::Path(p)) = single_contained {
1023                                         if self.c_type_has_inner_from_path(&self.resolve_path(&p.path, generics)) {
1024                                                 if is_ref {
1025                                                         return Some(("if ", vec![(".inner.is_null() { None } else { Some((*".to_string(), format!("{}", var_access))], ").clone()) }"))
1026                                                 } else {
1027                                                         return Some(("if ", vec![(".inner.is_null() { None } else { Some(".to_string(), format!("{}", var_access))], ") }"));
1028                                                 }
1029                                         }
1030                                 }
1031
1032                                 if let Some(t) = single_contained {
1033                                         let mut v = Vec::new();
1034                                         let ret_ref = self.write_empty_rust_val_check_suffix(generics, &mut v, t);
1035                                         let s = String::from_utf8(v).unwrap();
1036                                         match ret_ref {
1037                                                 EmptyValExpectedTy::ReferenceAsPointer =>
1038                                                         return Some(("if ", vec![
1039                                                                 (format!("{} {{ None }} else {{ Some(", s), format!("unsafe {{ &mut *{} }}", var_access))
1040                                                         ], ") }")),
1041                                                 EmptyValExpectedTy::OwnedPointer =>
1042                                                         return Some(("if ", vec![
1043                                                                 (format!("{} {{ None }} else {{ Some(", s), format!("unsafe {{ *Box::from_raw({}) }}", var_access))
1044                                                         ], ") }")),
1045                                                 EmptyValExpectedTy::NonPointer =>
1046                                                         return Some(("if ", vec![
1047                                                                 (format!("{} {{ None }} else {{ Some(", s), format!("{}", var_access))
1048                                                         ], ") }")),
1049                                         }
1050                                 } else { unreachable!(); }
1051                         },
1052                         _ => None,
1053                 }
1054         }
1055
1056         // *************************************************
1057         // *** Type definition during main.rs processing ***
1058         // *************************************************
1059
1060         pub fn get_declared_type(&'a self, ident: &syn::Ident) -> Option<&'a DeclType<'c>> {
1061                 self.types.get_declared_type(ident)
1062         }
1063         /// Returns true if the object at the given path is mapped as X { inner: *mut origX, .. }.
1064         pub fn c_type_has_inner_from_path(&self, full_path: &str) -> bool{
1065                 self.crate_types.opaques.get(full_path).is_some()
1066         }
1067
1068         pub fn maybe_resolve_ident(&self, id: &syn::Ident) -> Option<String> {
1069                 self.types.maybe_resolve_ident(id)
1070         }
1071
1072         pub fn maybe_resolve_non_ignored_ident(&self, id: &syn::Ident) -> Option<String> {
1073                 self.types.maybe_resolve_non_ignored_ident(id)
1074         }
1075
1076         pub fn maybe_resolve_path(&self, p_arg: &syn::Path, generics: Option<&GenericTypes>) -> Option<String> {
1077                 self.types.maybe_resolve_path(p_arg, generics)
1078         }
1079         pub fn resolve_path(&self, p: &syn::Path, generics: Option<&GenericTypes>) -> String {
1080                 self.maybe_resolve_path(p, generics).unwrap()
1081         }
1082
1083         // ***********************************
1084         // *** Original Rust Type Printing ***
1085         // ***********************************
1086
1087         fn in_rust_prelude(resolved_path: &str) -> bool {
1088                 match resolved_path {
1089                         "Vec" => true,
1090                         "Result" => true,
1091                         "Option" => true,
1092                         _ => false,
1093                 }
1094         }
1095
1096         fn write_rust_path<W: std::io::Write>(&self, w: &mut W, generics_resolver: Option<&GenericTypes>, path: &syn::Path) {
1097                 if let Some(resolved) = self.maybe_resolve_path(&path, generics_resolver) {
1098                         if self.is_primitive(&resolved) {
1099                                 write!(w, "{}", path.get_ident().unwrap()).unwrap();
1100                         } else {
1101                                 // TODO: We should have a generic "is from a dependency" check here instead of
1102                                 // checking for "bitcoin" explicitly.
1103                                 if resolved.starts_with("bitcoin::") || Self::in_rust_prelude(&resolved) {
1104                                         write!(w, "{}", resolved).unwrap();
1105                                 // If we're printing a generic argument, it needs to reference the crate, otherwise
1106                                 // the original crate:
1107                                 } else if self.maybe_resolve_path(&path, None).as_ref() == Some(&resolved) {
1108                                         write!(w, "{}::{}", self.orig_crate, resolved).unwrap();
1109                                 } else {
1110                                         write!(w, "crate::{}", resolved).unwrap();
1111                                 }
1112                         }
1113                         if let syn::PathArguments::AngleBracketed(args) = &path.segments.iter().last().unwrap().arguments {
1114                                 self.write_rust_generic_arg(w, generics_resolver, args.args.iter());
1115                         }
1116                 } else {
1117                         if path.leading_colon.is_some() {
1118                                 write!(w, "::").unwrap();
1119                         }
1120                         for (idx, seg) in path.segments.iter().enumerate() {
1121                                 if idx != 0 { write!(w, "::").unwrap(); }
1122                                 write!(w, "{}", seg.ident).unwrap();
1123                                 if let syn::PathArguments::AngleBracketed(args) = &seg.arguments {
1124                                         self.write_rust_generic_arg(w, generics_resolver, args.args.iter());
1125                                 }
1126                         }
1127                 }
1128         }
1129         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>) {
1130                 let mut had_params = false;
1131                 for (idx, arg) in generics.enumerate() {
1132                         if idx != 0 { write!(w, ", ").unwrap(); } else { write!(w, "<").unwrap(); }
1133                         had_params = true;
1134                         match arg {
1135                                 syn::GenericParam::Lifetime(lt) => write!(w, "'{}", lt.lifetime.ident).unwrap(),
1136                                 syn::GenericParam::Type(t) => {
1137                                         write!(w, "{}", t.ident).unwrap();
1138                                         if t.colon_token.is_some() { write!(w, ":").unwrap(); }
1139                                         for (idx, bound) in t.bounds.iter().enumerate() {
1140                                                 if idx != 0 { write!(w, " + ").unwrap(); }
1141                                                 match bound {
1142                                                         syn::TypeParamBound::Trait(tb) => {
1143                                                                 if tb.paren_token.is_some() || tb.lifetimes.is_some() { unimplemented!(); }
1144                                                                 self.write_rust_path(w, generics_resolver, &tb.path);
1145                                                         },
1146                                                         _ => unimplemented!(),
1147                                                 }
1148                                         }
1149                                         if t.eq_token.is_some() || t.default.is_some() { unimplemented!(); }
1150                                 },
1151                                 _ => unimplemented!(),
1152                         }
1153                 }
1154                 if had_params { write!(w, ">").unwrap(); }
1155         }
1156
1157         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>) {
1158                 write!(w, "<").unwrap();
1159                 for (idx, arg) in generics.enumerate() {
1160                         if idx != 0 { write!(w, ", ").unwrap(); }
1161                         match arg {
1162                                 syn::GenericArgument::Type(t) => self.write_rust_type(w, generics_resolver, t),
1163                                 _ => unimplemented!(),
1164                         }
1165                 }
1166                 write!(w, ">").unwrap();
1167         }
1168         pub fn write_rust_type<W: std::io::Write>(&self, w: &mut W, generics: Option<&GenericTypes>, t: &syn::Type) {
1169                 match t {
1170                         syn::Type::Path(p) => {
1171                                 if p.qself.is_some() {
1172                                         unimplemented!();
1173                                 }
1174                                 self.write_rust_path(w, generics, &p.path);
1175                         },
1176                         syn::Type::Reference(r) => {
1177                                 write!(w, "&").unwrap();
1178                                 if let Some(lft) = &r.lifetime {
1179                                         write!(w, "'{} ", lft.ident).unwrap();
1180                                 }
1181                                 if r.mutability.is_some() {
1182                                         write!(w, "mut ").unwrap();
1183                                 }
1184                                 self.write_rust_type(w, generics, &*r.elem);
1185                         },
1186                         syn::Type::Array(a) => {
1187                                 write!(w, "[").unwrap();
1188                                 self.write_rust_type(w, generics, &a.elem);
1189                                 if let syn::Expr::Lit(l) = &a.len {
1190                                         if let syn::Lit::Int(i) = &l.lit {
1191                                                 write!(w, "; {}]", i).unwrap();
1192                                         } else { unimplemented!(); }
1193                                 } else { unimplemented!(); }
1194                         }
1195                         syn::Type::Slice(s) => {
1196                                 write!(w, "[").unwrap();
1197                                 self.write_rust_type(w, generics, &s.elem);
1198                                 write!(w, "]").unwrap();
1199                         },
1200                         syn::Type::Tuple(s) => {
1201                                 write!(w, "(").unwrap();
1202                                 for (idx, t) in s.elems.iter().enumerate() {
1203                                         if idx != 0 { write!(w, ", ").unwrap(); }
1204                                         self.write_rust_type(w, generics, &t);
1205                                 }
1206                                 write!(w, ")").unwrap();
1207                         },
1208                         _ => unimplemented!(),
1209                 }
1210         }
1211
1212         /// Prints a constructor for something which is "uninitialized" (but obviously not actually
1213         /// unint'd memory).
1214         pub fn write_empty_rust_val<W: std::io::Write>(&self, generics: Option<&GenericTypes>, w: &mut W, t: &syn::Type) {
1215                 match t {
1216                         syn::Type::Path(p) => {
1217                                 let resolved = self.resolve_path(&p.path, generics);
1218                                 if self.crate_types.opaques.get(&resolved).is_some() {
1219                                         write!(w, "crate::{} {{ inner: std::ptr::null_mut(), is_owned: true }}", resolved).unwrap();
1220                                 } else {
1221                                         // Assume its a manually-mapped C type, where we can just define an null() fn
1222                                         write!(w, "{}::null()", self.c_type_from_path(&resolved, false, false).unwrap()).unwrap();
1223                                 }
1224                         },
1225                         syn::Type::Array(a) => {
1226                                 if let syn::Expr::Lit(l) = &a.len {
1227                                         if let syn::Lit::Int(i) = &l.lit {
1228                                                 if i.base10_digits().parse::<usize>().unwrap() < 32 {
1229                                                         // Blindly assume that if we're trying to create an empty value for an
1230                                                         // array < 32 entries that all-0s may be a valid state.
1231                                                         unimplemented!();
1232                                                 }
1233                                                 let arrty = format!("[u8; {}]", i.base10_digits());
1234                                                 write!(w, "{}", self.to_c_conversion_inline_prefix_from_path(&arrty, false, false).unwrap()).unwrap();
1235                                                 write!(w, "[0; {}]", i.base10_digits()).unwrap();
1236                                                 write!(w, "{}", self.to_c_conversion_inline_suffix_from_path(&arrty, false, false).unwrap()).unwrap();
1237                                         } else { unimplemented!(); }
1238                                 } else { unimplemented!(); }
1239                         }
1240                         _ => unimplemented!(),
1241                 }
1242         }
1243
1244         /// Prints a suffix to determine if a variable is empty (ie was set by write_empty_rust_val).
1245         /// See EmptyValExpectedTy for information on return types.
1246         fn write_empty_rust_val_check_suffix<W: std::io::Write>(&self, generics: Option<&GenericTypes>, w: &mut W, t: &syn::Type) -> EmptyValExpectedTy {
1247                 match t {
1248                         syn::Type::Path(p) => {
1249                                 let resolved = self.resolve_path(&p.path, generics);
1250                                 if self.crate_types.opaques.get(&resolved).is_some() {
1251                                         write!(w, ".inner.is_null()").unwrap();
1252                                         EmptyValExpectedTy::NonPointer
1253                                 } else {
1254                                         if let Some(suffix) = self.empty_val_check_suffix_from_path(&resolved) {
1255                                                 write!(w, "{}", suffix).unwrap();
1256                                                 // We may eventually need to allow empty_val_check_suffix_from_path to specify if we need a deref or not
1257                                                 EmptyValExpectedTy::NonPointer
1258                                         } else {
1259                                                 write!(w, " == std::ptr::null_mut()").unwrap();
1260                                                 EmptyValExpectedTy::OwnedPointer
1261                                         }
1262                                 }
1263                         },
1264                         syn::Type::Array(a) => {
1265                                 if let syn::Expr::Lit(l) = &a.len {
1266                                         if let syn::Lit::Int(i) = &l.lit {
1267                                                 write!(w, " == [0; {}]", i.base10_digits()).unwrap();
1268                                                 EmptyValExpectedTy::NonPointer
1269                                         } else { unimplemented!(); }
1270                                 } else { unimplemented!(); }
1271                         },
1272                         syn::Type::Slice(_) => {
1273                                 // Option<[]> always implies that we want to treat len() == 0 differently from
1274                                 // None, so we always map an Option<[]> into a pointer.
1275                                 write!(w, " == std::ptr::null_mut()").unwrap();
1276                                 EmptyValExpectedTy::ReferenceAsPointer
1277                         },
1278                         _ => unimplemented!(),
1279                 }
1280         }
1281
1282         /// Prints a suffix to determine if a variable is empty (ie was set by write_empty_rust_val).
1283         pub fn write_empty_rust_val_check<W: std::io::Write>(&self, generics: Option<&GenericTypes>, w: &mut W, t: &syn::Type, var_access: &str) {
1284                 match t {
1285                         syn::Type::Path(_) => {
1286                                 write!(w, "{}", var_access).unwrap();
1287                                 self.write_empty_rust_val_check_suffix(generics, w, t);
1288                         },
1289                         syn::Type::Array(a) => {
1290                                 if let syn::Expr::Lit(l) = &a.len {
1291                                         if let syn::Lit::Int(i) = &l.lit {
1292                                                 let arrty = format!("[u8; {}]", i.base10_digits());
1293                                                 // We don't (yet) support a new-var conversion here.
1294                                                 assert!(self.from_c_conversion_new_var_from_path(&arrty, false).is_none());
1295                                                 write!(w, "{}{}{}",
1296                                                         self.from_c_conversion_prefix_from_path(&arrty, false).unwrap(),
1297                                                         var_access,
1298                                                         self.from_c_conversion_suffix_from_path(&arrty, false).unwrap()).unwrap();
1299                                                 self.write_empty_rust_val_check_suffix(generics, w, t);
1300                                         } else { unimplemented!(); }
1301                                 } else { unimplemented!(); }
1302                         }
1303                         _ => unimplemented!(),
1304                 }
1305         }
1306
1307         // ********************************
1308         // *** Type conversion printing ***
1309         // ********************************
1310
1311         /// Returns true we if can just skip passing this to C entirely
1312         pub fn skip_arg(&self, t: &syn::Type, generics: Option<&GenericTypes>) -> bool {
1313                 match t {
1314                         syn::Type::Path(p) => {
1315                                 if p.qself.is_some() { unimplemented!(); }
1316                                 if let Some(full_path) = self.maybe_resolve_path(&p.path, generics) {
1317                                         self.skip_path(&full_path)
1318                                 } else { false }
1319                         },
1320                         syn::Type::Reference(r) => {
1321                                 self.skip_arg(&*r.elem, generics)
1322                         },
1323                         _ => false,
1324                 }
1325         }
1326         pub fn no_arg_to_rust<W: std::io::Write>(&self, w: &mut W, t: &syn::Type, generics: Option<&GenericTypes>) {
1327                 match t {
1328                         syn::Type::Path(p) => {
1329                                 if p.qself.is_some() { unimplemented!(); }
1330                                 if let Some(full_path) = self.maybe_resolve_path(&p.path, generics) {
1331                                         write!(w, "{}", self.no_arg_path_to_rust(&full_path)).unwrap();
1332                                 }
1333                         },
1334                         syn::Type::Reference(r) => {
1335                                 self.no_arg_to_rust(w, &*r.elem, generics);
1336                         },
1337                         _ => {},
1338                 }
1339         }
1340
1341         fn write_conversion_inline_intern<W: std::io::Write,
1342                         LP: Fn(&str, bool, bool) -> Option<String>, DL: Fn(&mut W, &DeclType, &str, bool, bool), SC: Fn(bool) -> &'static str>
1343                         (&self, w: &mut W, t: &syn::Type, generics: Option<&GenericTypes>, is_ref: bool, is_mut: bool, ptr_for_ref: bool,
1344                          tupleconv: &str, prefix: bool, sliceconv: SC, path_lookup: LP, decl_lookup: DL) {
1345                 match t {
1346                         syn::Type::Reference(r) => {
1347                                 self.write_conversion_inline_intern(w, &*r.elem, generics, true, r.mutability.is_some(),
1348                                         ptr_for_ref, tupleconv, prefix, sliceconv, path_lookup, decl_lookup);
1349                         },
1350                         syn::Type::Path(p) => {
1351                                 if p.qself.is_some() {
1352                                         unimplemented!();
1353                                 }
1354
1355                                 let resolved_path = self.resolve_path(&p.path, generics);
1356                                 if let Some(aliased_type) = self.crate_types.type_aliases.get(&resolved_path) {
1357                                         return self.write_conversion_inline_intern(w, aliased_type, None, is_ref, is_mut, ptr_for_ref, tupleconv, prefix, sliceconv, path_lookup, decl_lookup);
1358                                 } else if let Some(c_type) = path_lookup(&resolved_path, is_ref, ptr_for_ref) {
1359                                         write!(w, "{}", c_type).unwrap();
1360                                 } else if self.crate_types.opaques.get(&resolved_path).is_some() {
1361                                         decl_lookup(w, &DeclType::StructImported, &resolved_path, is_ref, is_mut);
1362                                 } else if self.crate_types.mirrored_enums.get(&resolved_path).is_some() {
1363                                         decl_lookup(w, &DeclType::MirroredEnum, &resolved_path, is_ref, is_mut);
1364                                 } else if let Some(t) = self.crate_types.traits.get(&resolved_path) {
1365                                         decl_lookup(w, &DeclType::Trait(t), &resolved_path, is_ref, is_mut);
1366                                 } else if let Some(ident) = single_ident_generic_path_to_ident(&p.path) {
1367                                         if let Some(decl_type) = self.types.maybe_resolve_declared(ident) {
1368                                                 decl_lookup(w, decl_type, &self.maybe_resolve_ident(ident).unwrap(), is_ref, is_mut);
1369                                         } else { unimplemented!(); }
1370                                 } else { unimplemented!(); }
1371                         },
1372                         syn::Type::Array(a) => {
1373                                 // We assume all arrays contain only [int_literal; X]s.
1374                                 // This may result in some outputs not compiling.
1375                                 if let syn::Expr::Lit(l) = &a.len {
1376                                         if let syn::Lit::Int(i) = &l.lit {
1377                                                 write!(w, "{}", path_lookup(&format!("[u8; {}]", i.base10_digits()), is_ref, ptr_for_ref).unwrap()).unwrap();
1378                                         } else { unimplemented!(); }
1379                                 } else { unimplemented!(); }
1380                         },
1381                         syn::Type::Slice(s) => {
1382                                 // We assume all slices contain only literals or references.
1383                                 // This may result in some outputs not compiling.
1384                                 if let syn::Type::Path(p) = &*s.elem {
1385                                         let resolved = self.resolve_path(&p.path, generics);
1386                                         assert!(self.is_primitive(&resolved));
1387                                         write!(w, "{}", path_lookup("[u8]", is_ref, ptr_for_ref).unwrap()).unwrap();
1388                                 } else if let syn::Type::Reference(r) = &*s.elem {
1389                                         if let syn::Type::Path(p) = &*r.elem {
1390                                                 write!(w, "{}", sliceconv(self.c_type_has_inner_from_path(&self.resolve_path(&p.path, generics)))).unwrap();
1391                                         } else { unimplemented!(); }
1392                                 } else if let syn::Type::Tuple(t) = &*s.elem {
1393                                         assert!(!t.elems.is_empty());
1394                                         if prefix {
1395                                                 write!(w, "&local_").unwrap();
1396                                         } else {
1397                                                 let mut needs_map = false;
1398                                                 for e in t.elems.iter() {
1399                                                         if let syn::Type::Reference(_) = e {
1400                                                                 needs_map = true;
1401                                                         }
1402                                                 }
1403                                                 if needs_map {
1404                                                         write!(w, ".iter().map(|(").unwrap();
1405                                                         for i in 0..t.elems.len() {
1406                                                                 write!(w, "{}{}", if i != 0 { ", " } else { "" }, ('a' as u8 + i as u8) as char).unwrap();
1407                                                         }
1408                                                         write!(w, ")| (").unwrap();
1409                                                         for (idx, e) in t.elems.iter().enumerate() {
1410                                                                 if let syn::Type::Reference(_) = e {
1411                                                                         write!(w, "{}{}", if idx != 0 { ", " } else { "" }, (idx as u8 + 'a' as u8) as char).unwrap();
1412                                                                 } else if let syn::Type::Path(_) = e {
1413                                                                         write!(w, "{}*{}", if idx != 0 { ", " } else { "" }, (idx as u8 + 'a' as u8) as char).unwrap();
1414                                                                 } else { unimplemented!(); }
1415                                                         }
1416                                                         write!(w, ")).collect::<Vec<_>>()[..]").unwrap();
1417                                                 }
1418                                         }
1419                                 } else { unimplemented!(); }
1420                         },
1421                         syn::Type::Tuple(t) => {
1422                                 if t.elems.is_empty() {
1423                                         // cbindgen has poor support for (), see, eg https://github.com/eqrion/cbindgen/issues/527
1424                                         // so work around it by just pretending its a 0u8
1425                                         write!(w, "{}", tupleconv).unwrap();
1426                                 } else {
1427                                         if prefix { write!(w, "local_").unwrap(); }
1428                                 }
1429                         },
1430                         _ => unimplemented!(),
1431                 }
1432         }
1433
1434         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) {
1435                 self.write_conversion_inline_intern(w, t, generics, is_ref, false, ptr_for_ref, "0u8 /*", true, |_| "local_",
1436                                 |a, b, c| self.to_c_conversion_inline_prefix_from_path(a, b, c),
1437                                 |w, decl_type, decl_path, is_ref, _is_mut| {
1438                                         match decl_type {
1439                                                 DeclType::MirroredEnum if is_ref && ptr_for_ref => write!(w, "crate::{}::from_native(&", decl_path).unwrap(),
1440                                                 DeclType::MirroredEnum if is_ref => write!(w, "&crate::{}::from_native(&", decl_path).unwrap(),
1441                                                 DeclType::MirroredEnum => write!(w, "crate::{}::native_into(", decl_path).unwrap(),
1442                                                 DeclType::EnumIgnored|DeclType::StructImported if is_ref && ptr_for_ref && from_ptr =>
1443                                                         write!(w, "crate::{} {{ inner: unsafe {{ (", decl_path).unwrap(),
1444                                                 DeclType::EnumIgnored|DeclType::StructImported if is_ref && ptr_for_ref =>
1445                                                         write!(w, "crate::{} {{ inner: unsafe {{ ( (&(", decl_path).unwrap(),
1446                                                 DeclType::EnumIgnored|DeclType::StructImported if is_ref =>
1447                                                         write!(w, "&crate::{} {{ inner: unsafe {{ (", decl_path).unwrap(),
1448                                                 DeclType::EnumIgnored|DeclType::StructImported if !is_ref && from_ptr =>
1449                                                         write!(w, "crate::{} {{ inner: ", decl_path).unwrap(),
1450                                                 DeclType::EnumIgnored|DeclType::StructImported if !is_ref =>
1451                                                         write!(w, "crate::{} {{ inner: Box::into_raw(Box::new(", decl_path).unwrap(),
1452                                                 DeclType::Trait(_) if is_ref => write!(w, "&").unwrap(),
1453                                                 DeclType::Trait(_) if !is_ref => {},
1454                                                 _ => panic!("{:?}", decl_path),
1455                                         }
1456                                 });
1457         }
1458         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) {
1459                 self.write_to_c_conversion_inline_prefix_inner(w, t, generics, false, ptr_for_ref, false);
1460         }
1461         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) {
1462                 self.write_conversion_inline_intern(w, t, generics, is_ref, false, ptr_for_ref, "*/", false, |_| ".into()",
1463                                 |a, b, c| self.to_c_conversion_inline_suffix_from_path(a, b, c),
1464                                 |w, decl_type, _full_path, is_ref, _is_mut| match decl_type {
1465                                         DeclType::MirroredEnum => write!(w, ")").unwrap(),
1466                                         DeclType::EnumIgnored|DeclType::StructImported if is_ref && ptr_for_ref && from_ptr =>
1467                                                 write!(w, " as *const _) as *mut _ }}, is_owned: false }}").unwrap(),
1468                                         DeclType::EnumIgnored|DeclType::StructImported if is_ref && ptr_for_ref =>
1469                                                 write!(w, ") as *const _) as *mut _) }}, is_owned: false }}").unwrap(),
1470                                         DeclType::EnumIgnored|DeclType::StructImported if is_ref =>
1471                                                 write!(w, " as *const _) as *mut _ }}, is_owned: false }}").unwrap(),
1472                                         DeclType::EnumIgnored|DeclType::StructImported if !is_ref && from_ptr =>
1473                                                 write!(w, ", is_owned: true }}").unwrap(),
1474                                         DeclType::EnumIgnored|DeclType::StructImported if !is_ref => write!(w, ")), is_owned: true }}").unwrap(),
1475                                         DeclType::Trait(_) if is_ref => {},
1476                                         DeclType::Trait(_) => {
1477                                                 // This is used when we're converting a concrete Rust type into a C trait
1478                                                 // for use when a Rust trait method returns an associated type.
1479                                                 // Because all of our C traits implement From<RustTypesImplementingTraits>
1480                                                 // we can just call .into() here and be done.
1481                                                 write!(w, ".into()").unwrap()
1482                                         },
1483                                         _ => unimplemented!(),
1484                                 });
1485         }
1486         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) {
1487                 self.write_to_c_conversion_inline_suffix_inner(w, t, generics, false, ptr_for_ref, false);
1488         }
1489
1490         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) {
1491                 self.write_conversion_inline_intern(w, t, generics, is_ref, false, false, "() /*", true, |_| "&local_",
1492                                 |a, b, _c| self.from_c_conversion_prefix_from_path(a, b),
1493                                 |w, decl_type, _full_path, is_ref, is_mut| match decl_type {
1494                                         DeclType::StructImported if is_ref && ptr_for_ref => write!(w, "unsafe {{ &*(*").unwrap(),
1495                                         DeclType::StructImported if is_mut && is_ref => write!(w, "unsafe {{ &mut *").unwrap(),
1496                                         DeclType::StructImported if is_ref => write!(w, "unsafe {{ &*").unwrap(),
1497                                         DeclType::StructImported if !is_ref => write!(w, "*unsafe {{ Box::from_raw(").unwrap(),
1498                                         DeclType::MirroredEnum if is_ref => write!(w, "&").unwrap(),
1499                                         DeclType::MirroredEnum => {},
1500                                         DeclType::Trait(_) => {},
1501                                         _ => unimplemented!(),
1502                                 });
1503         }
1504         pub fn write_from_c_conversion_prefix<W: std::io::Write>(&self, w: &mut W, t: &syn::Type, generics: Option<&GenericTypes>) {
1505                 self.write_from_c_conversion_prefix_inner(w, t, generics, false, false);
1506         }
1507         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) {
1508                 self.write_conversion_inline_intern(w, t, generics, is_ref, false, false, "*/", false,
1509                                 |has_inner| match has_inner {
1510                                         false => ".iter().collect::<Vec<_>>()[..]",
1511                                         true => "[..]",
1512                                 },
1513                                 |a, b, _c| self.from_c_conversion_suffix_from_path(a, b),
1514                                 |w, decl_type, _full_path, is_ref, _is_mut| match decl_type {
1515                                         DeclType::StructImported if is_ref && ptr_for_ref => write!(w, ").inner }}").unwrap(),
1516                                         DeclType::StructImported if is_ref => write!(w, ".inner }}").unwrap(),
1517                                         DeclType::StructImported if !is_ref => write!(w, ".take_inner()) }}").unwrap(),
1518                                         DeclType::MirroredEnum if is_ref => write!(w, ".to_native()").unwrap(),
1519                                         DeclType::MirroredEnum => write!(w, ".into_native()").unwrap(),
1520                                         DeclType::Trait(_) => {},
1521                                         _ => unimplemented!(),
1522                                 });
1523         }
1524         pub fn write_from_c_conversion_suffix<W: std::io::Write>(&self, w: &mut W, t: &syn::Type, generics: Option<&GenericTypes>) {
1525                 self.write_from_c_conversion_suffix_inner(w, t, generics, false, false);
1526         }
1527         // Note that compared to the above conversion functions, the following two are generally
1528         // significantly undertested:
1529         pub fn write_from_c_conversion_to_ref_prefix<W: std::io::Write>(&self, w: &mut W, t: &syn::Type, generics: Option<&GenericTypes>) {
1530                 self.write_conversion_inline_intern(w, t, generics, false, false, false, "() /*", true, |_| "&local_",
1531                                 |a, b, _c| {
1532                                         if let Some(conv) = self.from_c_conversion_prefix_from_path(a, b) {
1533                                                 Some(format!("&{}", conv))
1534                                         } else { None }
1535                                 },
1536                                 |w, decl_type, _full_path, is_ref, _is_mut| match decl_type {
1537                                         DeclType::StructImported if !is_ref => write!(w, "unsafe {{ &*").unwrap(),
1538                                         _ => unimplemented!(),
1539                                 });
1540         }
1541         pub fn write_from_c_conversion_to_ref_suffix<W: std::io::Write>(&self, w: &mut W, t: &syn::Type, generics: Option<&GenericTypes>) {
1542                 self.write_conversion_inline_intern(w, t, generics, false, false, false, "*/", false,
1543                                 |has_inner| match has_inner {
1544                                         false => ".iter().collect::<Vec<_>>()[..]",
1545                                         true => "[..]",
1546                                 },
1547                                 |a, b, _c| self.from_c_conversion_suffix_from_path(a, b),
1548                                 |w, decl_type, _full_path, is_ref, _is_mut| match decl_type {
1549                                         DeclType::StructImported if !is_ref => write!(w, ".inner }}").unwrap(),
1550                                         _ => unimplemented!(),
1551                                 });
1552         }
1553
1554         fn write_conversion_new_var_intern<'b, W: std::io::Write,
1555                 LP: Fn(&str, bool) -> Option<(&str, &str)>,
1556                 LC: Fn(&str, bool, Option<&syn::Type>, &syn::Ident, &str) ->  Option<(&'b str, Vec<(String, String)>, &'b str)>,
1557                 VP: Fn(&mut W, &syn::Type, Option<&GenericTypes>, bool, bool, bool),
1558                 VS: Fn(&mut W, &syn::Type, Option<&GenericTypes>, bool, bool, bool)>
1559                         (&self, w: &mut W, ident: &syn::Ident, var: &str, t: &syn::Type, generics: Option<&GenericTypes>,
1560                          mut is_ref: bool, mut ptr_for_ref: bool, to_c: bool,
1561                          path_lookup: &LP, container_lookup: &LC, var_prefix: &VP, var_suffix: &VS) -> bool {
1562
1563                 macro_rules! convert_container {
1564                         ($container_type: expr, $args_len: expr, $args_iter: expr) => { {
1565                                 // For slices (and Options), we refuse to directly map them as is_ref when they
1566                                 // aren't opaque types containing an inner pointer. This is due to the fact that,
1567                                 // in both cases, the actual higher-level type is non-is_ref.
1568                                 let ty_has_inner = if self.is_transparent_container(&$container_type, is_ref) || $container_type == "Slice" {
1569                                         let ty = $args_iter().next().unwrap();
1570                                         if $container_type == "Slice" && to_c {
1571                                                 // "To C ptr_for_ref" means "return the regular object with is_owned
1572                                                 // set to false", which is totally what we want in a slice if we're about to
1573                                                 // set ty_has_inner.
1574                                                 ptr_for_ref = true;
1575                                         }
1576                                         if let syn::Type::Reference(t) = ty {
1577                                                 if let syn::Type::Path(p) = &*t.elem {
1578                                                         self.c_type_has_inner_from_path(&self.resolve_path(&p.path, generics))
1579                                                 } else { false }
1580                                         } else if let syn::Type::Path(p) = ty {
1581                                                 self.c_type_has_inner_from_path(&self.resolve_path(&p.path, generics))
1582                                         } else { false }
1583                                 } else { true };
1584
1585                                 // Options get a bunch of special handling, since in general we map Option<>al
1586                                 // types into the same C type as non-Option-wrapped types. This ends up being
1587                                 // pretty manual here and most of the below special-cases are for Options.
1588                                 let mut needs_ref_map = false;
1589                                 let mut only_contained_type = None;
1590                                 let mut only_contained_has_inner = false;
1591                                 let mut contains_slice = false;
1592                                 if $args_len == 1 && self.is_transparent_container(&$container_type, is_ref) {
1593                                         only_contained_has_inner = ty_has_inner;
1594                                         let arg = $args_iter().next().unwrap();
1595                                         if let syn::Type::Reference(t) = arg {
1596                                                 only_contained_type = Some(&*t.elem);
1597                                                 if let syn::Type::Path(_) = &*t.elem {
1598                                                         is_ref = true;
1599                                                 } else if let syn::Type::Slice(_) = &*t.elem {
1600                                                         contains_slice = true;
1601                                                 } else { return false; }
1602                                                 needs_ref_map = true;
1603                                         } else if let syn::Type::Path(_) = arg {
1604                                                 only_contained_type = Some(&arg);
1605                                         } else { unimplemented!(); }
1606                                 }
1607
1608                                 if let Some((prefix, conversions, suffix)) = container_lookup(&$container_type, is_ref && ty_has_inner, only_contained_type, ident, var) {
1609                                         assert_eq!(conversions.len(), $args_len);
1610                                         write!(w, "let mut local_{}{} = ", ident, if !to_c && needs_ref_map {"_base"} else { "" }).unwrap();
1611                                         if only_contained_has_inner && to_c {
1612                                                 var_prefix(w, $args_iter().next().unwrap(), generics, is_ref, ptr_for_ref, true);
1613                                         }
1614                                         write!(w, "{}{}", prefix, var).unwrap();
1615
1616                                         for ((pfx, var_name), (idx, ty)) in conversions.iter().zip($args_iter().enumerate()) {
1617                                                 let mut var = std::io::Cursor::new(Vec::new());
1618                                                 write!(&mut var, "{}", var_name).unwrap();
1619                                                 let var_access = String::from_utf8(var.into_inner()).unwrap();
1620
1621                                                 let conv_ty = if needs_ref_map { only_contained_type.as_ref().unwrap() } else { ty };
1622
1623                                                 write!(w, "{} {{ ", pfx).unwrap();
1624                                                 let new_var_name = format!("{}_{}", ident, idx);
1625                                                 let new_var = self.write_conversion_new_var_intern(w, &syn::Ident::new(&new_var_name, Span::call_site()),
1626                                                                 &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);
1627                                                 if new_var { write!(w, " ").unwrap(); }
1628                                                 if (!only_contained_has_inner || !to_c) && !contains_slice {
1629                                                         var_prefix(w, conv_ty, generics, is_ref && ty_has_inner, ptr_for_ref, false);
1630                                                 }
1631
1632                                                 if !is_ref && !needs_ref_map && to_c && only_contained_has_inner {
1633                                                         write!(w, "Box::into_raw(Box::new(").unwrap();
1634                                                 }
1635                                                 write!(w, "{}{}", if contains_slice { "local_" } else { "" }, if new_var { new_var_name } else { var_access }).unwrap();
1636                                                 if (!only_contained_has_inner || !to_c) && !contains_slice {
1637                                                         var_suffix(w, conv_ty, generics, is_ref && ty_has_inner, ptr_for_ref, false);
1638                                                 }
1639                                                 if !is_ref && !needs_ref_map && to_c && only_contained_has_inner {
1640                                                         write!(w, "))").unwrap();
1641                                                 }
1642                                                 write!(w, " }}").unwrap();
1643                                         }
1644                                         write!(w, "{}", suffix).unwrap();
1645                                         if only_contained_has_inner && to_c {
1646                                                 var_suffix(w, $args_iter().next().unwrap(), generics, is_ref, ptr_for_ref, true);
1647                                         }
1648                                         write!(w, ";").unwrap();
1649                                         if !to_c && needs_ref_map {
1650                                                 write!(w, " let mut local_{} = local_{}_base.as_ref()", ident, ident).unwrap();
1651                                                 if contains_slice {
1652                                                         write!(w, ".map(|a| &a[..])").unwrap();
1653                                                 }
1654                                                 write!(w, ";").unwrap();
1655                                         }
1656                                         return true;
1657                                 }
1658                         } }
1659                 }
1660
1661                 match t {
1662                         syn::Type::Reference(r) => {
1663                                 if let syn::Type::Slice(_) = &*r.elem {
1664                                         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)
1665                                 } else {
1666                                         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)
1667                                 }
1668                         },
1669                         syn::Type::Path(p) => {
1670                                 if p.qself.is_some() {
1671                                         unimplemented!();
1672                                 }
1673                                 let resolved_path = self.resolve_path(&p.path, generics);
1674                                 if let Some(aliased_type) = self.crate_types.type_aliases.get(&resolved_path) {
1675                                         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);
1676                                 }
1677                                 if self.is_known_container(&resolved_path, is_ref) || self.is_transparent_container(&resolved_path, is_ref) {
1678                                         if let syn::PathArguments::AngleBracketed(args) = &p.path.segments.iter().next().unwrap().arguments {
1679                                                 convert_container!(resolved_path, args.args.len(), || args.args.iter().map(|arg| {
1680                                                         if let syn::GenericArgument::Type(ty) = arg {
1681                                                                 ty
1682                                                         } else { unimplemented!(); }
1683                                                 }));
1684                                         } else { unimplemented!(); }
1685                                 }
1686                                 if self.is_primitive(&resolved_path) {
1687                                         false
1688                                 } else if let Some(ty_ident) = single_ident_generic_path_to_ident(&p.path) {
1689                                         if let Some((prefix, suffix)) = path_lookup(&resolved_path, is_ref) {
1690                                                 write!(w, "let mut local_{} = {}{}{};", ident, prefix, var, suffix).unwrap();
1691                                                 true
1692                                         } else if self.types.maybe_resolve_declared(ty_ident).is_some() {
1693                                                 false
1694                                         } else { false }
1695                                 } else { false }
1696                         },
1697                         syn::Type::Array(_) => {
1698                                 // We assume all arrays contain only primitive types.
1699                                 // This may result in some outputs not compiling.
1700                                 false
1701                         },
1702                         syn::Type::Slice(s) => {
1703                                 if let syn::Type::Path(p) = &*s.elem {
1704                                         let resolved = self.resolve_path(&p.path, generics);
1705                                         assert!(self.is_primitive(&resolved));
1706                                         let slice_path = format!("[{}]", resolved);
1707                                         if let Some((prefix, suffix)) = path_lookup(&slice_path, true) {
1708                                                 write!(w, "let mut local_{} = {}{}{};", ident, prefix, var, suffix).unwrap();
1709                                                 true
1710                                         } else { false }
1711                                 } else if let syn::Type::Reference(ty) = &*s.elem {
1712                                         let tyref = [&*ty.elem];
1713                                         is_ref = true;
1714                                         convert_container!("Slice", 1, || tyref.iter());
1715                                         unimplemented!("convert_container should return true as container_lookup should succeed for slices");
1716                                 } else if let syn::Type::Tuple(t) = &*s.elem {
1717                                         // When mapping into a temporary new var, we need to own all the underlying objects.
1718                                         // Thus, we drop any references inside the tuple and convert with non-reference types.
1719                                         let mut elems = syn::punctuated::Punctuated::new();
1720                                         for elem in t.elems.iter() {
1721                                                 if let syn::Type::Reference(r) = elem {
1722                                                         elems.push((*r.elem).clone());
1723                                                 } else {
1724                                                         elems.push(elem.clone());
1725                                                 }
1726                                         }
1727                                         let ty = [syn::Type::Tuple(syn::TypeTuple {
1728                                                 paren_token: t.paren_token, elems
1729                                         })];
1730                                         is_ref = false;
1731                                         ptr_for_ref = true;
1732                                         convert_container!("Slice", 1, || ty.iter());
1733                                         unimplemented!("convert_container should return true as container_lookup should succeed for slices");
1734                                 } else { unimplemented!() }
1735                         },
1736                         syn::Type::Tuple(t) => {
1737                                 if !t.elems.is_empty() {
1738                                         // We don't (yet) support tuple elements which cannot be converted inline
1739                                         write!(w, "let (").unwrap();
1740                                         for idx in 0..t.elems.len() {
1741                                                 if idx != 0 { write!(w, ", ").unwrap(); }
1742                                                 write!(w, "{} orig_{}_{}", if is_ref { "ref" } else { "mut" }, ident, idx).unwrap();
1743                                         }
1744                                         write!(w, ") = {}{}; ", var, if !to_c { ".to_rust()" } else { "" }).unwrap();
1745                                         // Like other template types, tuples are always mapped as their non-ref
1746                                         // versions for types which have different ref mappings. Thus, we convert to
1747                                         // non-ref versions and handle opaque types with inner pointers manually.
1748                                         for (idx, elem) in t.elems.iter().enumerate() {
1749                                                 if let syn::Type::Path(p) = elem {
1750                                                         let v_name = format!("orig_{}_{}", ident, idx);
1751                                                         let tuple_elem_ident = syn::Ident::new(&v_name, Span::call_site());
1752                                                         if self.write_conversion_new_var_intern(w, &tuple_elem_ident, &v_name, elem, generics,
1753                                                                         false, ptr_for_ref, to_c,
1754                                                                         path_lookup, container_lookup, var_prefix, var_suffix) {
1755                                                                 write!(w, " ").unwrap();
1756                                                                 // Opaque types with inner pointers shouldn't ever create new stack
1757                                                                 // variables, so we don't handle it and just assert that it doesn't
1758                                                                 // here.
1759                                                                 assert!(!self.c_type_has_inner_from_path(&self.resolve_path(&p.path, generics)));
1760                                                         }
1761                                                 }
1762                                         }
1763                                         write!(w, "let mut local_{} = (", ident).unwrap();
1764                                         for (idx, elem) in t.elems.iter().enumerate() {
1765                                                 let ty_has_inner = {
1766                                                                 if to_c {
1767                                                                         // "To C ptr_for_ref" means "return the regular object with
1768                                                                         // is_owned set to false", which is totally what we want
1769                                                                         // if we're about to set ty_has_inner.
1770                                                                         ptr_for_ref = true;
1771                                                                 }
1772                                                                 if let syn::Type::Reference(t) = elem {
1773                                                                         if let syn::Type::Path(p) = &*t.elem {
1774                                                                                 self.c_type_has_inner_from_path(&self.resolve_path(&p.path, generics))
1775                                                                         } else { false }
1776                                                                 } else if let syn::Type::Path(p) = elem {
1777                                                                         self.c_type_has_inner_from_path(&self.resolve_path(&p.path, generics))
1778                                                                 } else { false }
1779                                                         };
1780                                                 if idx != 0 { write!(w, ", ").unwrap(); }
1781                                                 var_prefix(w, elem, generics, is_ref && ty_has_inner, ptr_for_ref, false);
1782                                                 if is_ref && ty_has_inner {
1783                                                         // For ty_has_inner, the regular var_prefix mapping will take a
1784                                                         // reference, so deref once here to make sure we keep the original ref.
1785                                                         write!(w, "*").unwrap();
1786                                                 }
1787                                                 write!(w, "orig_{}_{}", ident, idx).unwrap();
1788                                                 if is_ref && !ty_has_inner {
1789                                                         // If we don't have an inner variable's reference to maintain, just
1790                                                         // hope the type is Clonable and use that.
1791                                                         write!(w, ".clone()").unwrap();
1792                                                 }
1793                                                 var_suffix(w, elem, generics, is_ref && ty_has_inner, ptr_for_ref, false);
1794                                         }
1795                                         write!(w, "){};", if to_c { ".into()" } else { "" }).unwrap();
1796                                         true
1797                                 } else { false }
1798                         },
1799                         _ => unimplemented!(),
1800                 }
1801         }
1802
1803         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 {
1804                 self.write_conversion_new_var_intern(w, ident, var_access, t, generics, false, ptr_for_ref, true,
1805                         &|a, b| self.to_c_conversion_new_var_from_path(a, b),
1806                         &|a, b, c, d, e| self.to_c_conversion_container_new_var(generics, a, b, c, d, e),
1807                         // We force ptr_for_ref here since we can't generate a ref on one line and use it later
1808                         &|a, b, c, d, e, f| self.write_to_c_conversion_inline_prefix_inner(a, b, c, d, e, f),
1809                         &|a, b, c, d, e, f| self.write_to_c_conversion_inline_suffix_inner(a, b, c, d, e, f))
1810         }
1811         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 {
1812                 self.write_to_c_conversion_new_var_inner(w, ident, &format!("{}", ident), t, generics, ptr_for_ref)
1813         }
1814         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 {
1815                 self.write_conversion_new_var_intern(w, ident, &format!("{}", ident), t, generics, false, false, false,
1816                         &|a, b| self.from_c_conversion_new_var_from_path(a, b),
1817                         &|a, b, c, d, e| self.from_c_conversion_container_new_var(generics, a, b, c, d, e),
1818                         // We force ptr_for_ref here since we can't generate a ref on one line and use it later
1819                         &|a, b, c, d, e, _f| self.write_from_c_conversion_prefix_inner(a, b, c, d, e),
1820                         &|a, b, c, d, e, _f| self.write_from_c_conversion_suffix_inner(a, b, c, d, e))
1821         }
1822
1823         // ******************************************************
1824         // *** C Container Type Equivalent and alias Printing ***
1825         // ******************************************************
1826
1827         fn write_template_generics<'b, W: std::io::Write>(&mut self, w: &mut W, args: &mut dyn Iterator<Item=&'b syn::Type>, generics: Option<&GenericTypes>, is_ref: bool) -> bool {
1828                 assert!(!is_ref); // We don't currently support outer reference types
1829                 for (idx, t) in args.enumerate() {
1830                         if idx != 0 {
1831                                 write!(w, ", ").unwrap();
1832                         }
1833                         if let syn::Type::Reference(r_arg) = t {
1834                                 if !self.write_c_type_intern(w, &*r_arg.elem, generics, false, false, false) { return false; }
1835
1836                                 // While write_c_type_intern, above is correct, we don't want to blindly convert a
1837                                 // reference to something stupid, so check that the container is either opaque or a
1838                                 // predefined type (currently only Transaction).
1839                                 if let syn::Type::Path(p_arg) = &*r_arg.elem {
1840                                         let resolved = self.resolve_path(&p_arg.path, generics);
1841                                         assert!(self.crate_types.opaques.get(&resolved).is_some() ||
1842                                                         self.c_type_from_path(&resolved, true, true).is_some(), "Template generics should be opaque or have a predefined mapping");
1843                                 } else { unimplemented!(); }
1844                         } else {
1845                                 if !self.write_c_type_intern(w, t, generics, false, false, false) { return false; }
1846                         }
1847                 }
1848                 true
1849         }
1850         fn check_create_container(&mut self, mangled_container: String, container_type: &str, args: Vec<&syn::Type>, generics: Option<&GenericTypes>, is_ref: bool) -> bool {
1851                 if !self.crate_types.templates_defined.get(&mangled_container).is_some() {
1852                         let mut created_container: Vec<u8> = Vec::new();
1853
1854                         if container_type == "Result" {
1855                                 let mut a_ty: Vec<u8> = Vec::new();
1856                                 if let syn::Type::Tuple(tup) = args.iter().next().unwrap() {
1857                                         if tup.elems.is_empty() {
1858                                                 write!(&mut a_ty, "()").unwrap();
1859                                         } else {
1860                                                 if !self.write_template_generics(&mut a_ty, &mut args.iter().map(|t| *t).take(1), generics, is_ref) { return false; }
1861                                         }
1862                                 } else {
1863                                         if !self.write_template_generics(&mut a_ty, &mut args.iter().map(|t| *t).take(1), generics, is_ref) { return false; }
1864                                 }
1865
1866                                 let mut b_ty: Vec<u8> = Vec::new();
1867                                 if let syn::Type::Tuple(tup) = args.iter().skip(1).next().unwrap() {
1868                                         if tup.elems.is_empty() {
1869                                                 write!(&mut b_ty, "()").unwrap();
1870                                         } else {
1871                                                 if !self.write_template_generics(&mut b_ty, &mut args.iter().map(|t| *t).skip(1), generics, is_ref) { return false; }
1872                                         }
1873                                 } else {
1874                                         if !self.write_template_generics(&mut b_ty, &mut args.iter().map(|t| *t).skip(1), generics, is_ref) { return false; }
1875                                 }
1876
1877                                 let ok_str = String::from_utf8(a_ty).unwrap();
1878                                 let err_str = String::from_utf8(b_ty).unwrap();
1879                                 let is_clonable = self.is_clonable(&ok_str) && self.is_clonable(&err_str);
1880                                 write_result_block(&mut created_container, &mangled_container, &ok_str, &err_str, is_clonable);
1881                                 if is_clonable {
1882                                         self.crate_types.clonable_types.insert(Self::generated_container_path().to_owned() + "::" + &mangled_container);
1883                                 }
1884                         } else if container_type == "Vec" {
1885                                 let mut a_ty: Vec<u8> = Vec::new();
1886                                 if !self.write_template_generics(&mut a_ty, &mut args.iter().map(|t| *t), generics, is_ref) { return false; }
1887                                 let ty = String::from_utf8(a_ty).unwrap();
1888                                 let is_clonable = self.is_clonable(&ty);
1889                                 write_vec_block(&mut created_container, &mangled_container, &ty, is_clonable);
1890                                 if is_clonable {
1891                                         self.crate_types.clonable_types.insert(Self::generated_container_path().to_owned() + "::" + &mangled_container);
1892                                 }
1893                         } else if container_type.ends_with("Tuple") {
1894                                 let mut tuple_args = Vec::new();
1895                                 let mut is_clonable = true;
1896                                 for arg in args.iter() {
1897                                         let mut ty: Vec<u8> = Vec::new();
1898                                         if !self.write_template_generics(&mut ty, &mut [arg].iter().map(|t| **t), generics, is_ref) { return false; }
1899                                         let ty_str = String::from_utf8(ty).unwrap();
1900                                         if !self.is_clonable(&ty_str) {
1901                                                 is_clonable = false;
1902                                         }
1903                                         tuple_args.push(ty_str);
1904                                 }
1905                                 write_tuple_block(&mut created_container, &mangled_container, &tuple_args, is_clonable);
1906                                 if is_clonable {
1907                                         self.crate_types.clonable_types.insert(Self::generated_container_path().to_owned() + "::" + &mangled_container);
1908                                 }
1909                         } else {
1910                                 unreachable!();
1911                         }
1912                         self.crate_types.templates_defined.insert(mangled_container.clone(), true);
1913
1914                         self.crate_types.template_file.write(&created_container).unwrap();
1915                 }
1916                 true
1917         }
1918         fn path_to_generic_args(path: &syn::Path) -> Vec<&syn::Type> {
1919                 if let syn::PathArguments::AngleBracketed(args) = &path.segments.iter().next().unwrap().arguments {
1920                         args.args.iter().map(|gen| if let syn::GenericArgument::Type(t) = gen { t } else { unimplemented!() }).collect()
1921                 } else { unimplemented!(); }
1922         }
1923         fn write_c_mangled_container_path_intern<W: std::io::Write>
1924                         (&mut 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 {
1925                 let mut mangled_type: Vec<u8> = Vec::new();
1926                 if !self.is_transparent_container(ident, is_ref) {
1927                         write!(w, "C{}_", ident).unwrap();
1928                         write!(mangled_type, "C{}_", ident).unwrap();
1929                 } else { assert_eq!(args.len(), 1); }
1930                 for arg in args.iter() {
1931                         macro_rules! write_path {
1932                                 ($p_arg: expr, $extra_write: expr) => {
1933                                         if let Some(subtype) = self.maybe_resolve_path(&$p_arg.path, generics) {
1934                                                 if self.is_transparent_container(ident, is_ref) {
1935                                                         // We dont (yet) support primitives or containers inside transparent
1936                                                         // containers, so check for that first:
1937                                                         if self.is_primitive(&subtype) { return false; }
1938                                                         if self.is_known_container(&subtype, is_ref) { return false; }
1939                                                         if !in_type {
1940                                                                 if self.c_type_has_inner_from_path(&subtype) {
1941                                                                         if !self.write_c_path_intern(w, &$p_arg.path, generics, is_ref, is_mut, ptr_for_ref) { return false; }
1942                                                                 } else {
1943                                                                         // Option<T> needs to be converted to a *mut T, ie mut ptr-for-ref
1944                                                                         if !self.write_c_path_intern(w, &$p_arg.path, generics, true, true, true) { return false; }
1945                                                                 }
1946                                                         } else {
1947                                                                 if $p_arg.path.segments.len() == 1 {
1948                                                                         write!(w, "{}", $p_arg.path.segments.iter().next().unwrap().ident).unwrap();
1949                                                                 } else {
1950                                                                         return false;
1951                                                                 }
1952                                                         }
1953                                                 } else if self.is_known_container(&subtype, is_ref) || self.is_transparent_container(&subtype, is_ref) {
1954                                                         if !self.write_c_mangled_container_path_intern(w, Self::path_to_generic_args(&$p_arg.path), generics,
1955                                                                         &subtype, is_ref, is_mut, ptr_for_ref, true) {
1956                                                                 return false;
1957                                                         }
1958                                                         self.write_c_mangled_container_path_intern(&mut mangled_type, Self::path_to_generic_args(&$p_arg.path),
1959                                                                 generics, &subtype, is_ref, is_mut, ptr_for_ref, true);
1960                                                         if let Some(w2) = $extra_write as Option<&mut Vec<u8>> {
1961                                                                 self.write_c_mangled_container_path_intern(w2, Self::path_to_generic_args(&$p_arg.path),
1962                                                                         generics, &subtype, is_ref, is_mut, ptr_for_ref, true);
1963                                                         }
1964                                                 } else {
1965                                                         let id = subtype.rsplitn(2, ':').next().unwrap(); // Get the "Base" name of the resolved type
1966                                                         write!(w, "{}", id).unwrap();
1967                                                         write!(mangled_type, "{}", id).unwrap();
1968                                                         if let Some(w2) = $extra_write as Option<&mut Vec<u8>> {
1969                                                                 write!(w2, "{}", id).unwrap();
1970                                                         }
1971                                                 }
1972                                         } else { return false; }
1973                                 }
1974                         }
1975                         if let syn::Type::Tuple(tuple) = arg {
1976                                 if tuple.elems.len() == 0 {
1977                                         write!(w, "None").unwrap();
1978                                         write!(mangled_type, "None").unwrap();
1979                                 } else {
1980                                         let mut mangled_tuple_type: Vec<u8> = Vec::new();
1981
1982                                         // Figure out what the mangled type should look like. To disambiguate
1983                                         // ((A, B), C) and (A, B, C) we prefix the generic args with a _ and suffix
1984                                         // them with a Z. Ideally we wouldn't use Z, but not many special chars are
1985                                         // available for use in type names.
1986                                         write!(w, "C{}Tuple_", tuple.elems.len()).unwrap();
1987                                         write!(mangled_type, "C{}Tuple_", tuple.elems.len()).unwrap();
1988                                         write!(mangled_tuple_type, "C{}Tuple_", tuple.elems.len()).unwrap();
1989                                         for elem in tuple.elems.iter() {
1990                                                 if let syn::Type::Path(p) = elem {
1991                                                         write_path!(p, Some(&mut mangled_tuple_type));
1992                                                 } else if let syn::Type::Reference(refelem) = elem {
1993                                                         if let syn::Type::Path(p) = &*refelem.elem {
1994                                                                 write_path!(p, Some(&mut mangled_tuple_type));
1995                                                         } else { return false; }
1996                                                 } else { return false; }
1997                                         }
1998                                         write!(w, "Z").unwrap();
1999                                         write!(mangled_type, "Z").unwrap();
2000                                         write!(mangled_tuple_type, "Z").unwrap();
2001                                         if !self.check_create_container(String::from_utf8(mangled_tuple_type).unwrap(),
2002                                                         &format!("{}Tuple", tuple.elems.len()), tuple.elems.iter().collect(), generics, is_ref) {
2003                                                 return false;
2004                                         }
2005                                 }
2006                         } else if let syn::Type::Path(p_arg) = arg {
2007                                 write_path!(p_arg, None);
2008                         } else if let syn::Type::Reference(refty) = arg {
2009                                 if let syn::Type::Path(p_arg) = &*refty.elem {
2010                                         write_path!(p_arg, None);
2011                                 } else if let syn::Type::Slice(_) = &*refty.elem {
2012                                         // write_c_type will actually do exactly what we want here, we just need to
2013                                         // make it a pointer so that its an option. Note that we cannot always convert
2014                                         // the Vec-as-slice (ie non-ref types) containers, so sometimes need to be able
2015                                         // to edit it, hence we use *mut here instead of *const.
2016                                         if args.len() != 1 { return false; }
2017                                         write!(w, "*mut ").unwrap();
2018                                         self.write_c_type(w, arg, None, true);
2019                                 } else { return false; }
2020                         } else if let syn::Type::Array(a) = arg {
2021                                 if let syn::Type::Path(p_arg) = &*a.elem {
2022                                         let resolved = self.resolve_path(&p_arg.path, generics);
2023                                         if !self.is_primitive(&resolved) { return false; }
2024                                         if let syn::Expr::Lit(syn::ExprLit { lit: syn::Lit::Int(len), .. }) = &a.len {
2025                                                 if self.c_type_from_path(&format!("[{}; {}]", resolved, len.base10_digits()), is_ref, ptr_for_ref).is_none() { return false; }
2026                                                 write!(w, "_{}{}", resolved, len.base10_digits()).unwrap();
2027                                                 write!(mangled_type, "_{}{}", resolved, len.base10_digits()).unwrap();
2028                                         } else { return false; }
2029                                 } else { return false; }
2030                         } else { return false; }
2031                 }
2032                 if self.is_transparent_container(ident, is_ref) { return true; }
2033                 // Push the "end of type" Z
2034                 write!(w, "Z").unwrap();
2035                 write!(mangled_type, "Z").unwrap();
2036
2037                 // Make sure the type is actually defined:
2038                 self.check_create_container(String::from_utf8(mangled_type).unwrap(), ident, args, generics, is_ref)
2039         }
2040         fn write_c_mangled_container_path<W: std::io::Write>(&mut self, w: &mut W, args: Vec<&syn::Type>, generics: Option<&GenericTypes>, ident: &str, is_ref: bool, is_mut: bool, ptr_for_ref: bool) -> bool {
2041                 if !self.is_transparent_container(ident, is_ref) {
2042                         write!(w, "{}::", Self::generated_container_path()).unwrap();
2043                 }
2044                 self.write_c_mangled_container_path_intern(w, args, generics, ident, is_ref, is_mut, ptr_for_ref, false)
2045         }
2046
2047         // **********************************
2048         // *** C Type Equivalent Printing ***
2049         // **********************************
2050
2051         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 {
2052                 let full_path = match self.maybe_resolve_path(&path, generics) {
2053                         Some(path) => path, None => return false };
2054                 if let Some(c_type) = self.c_type_from_path(&full_path, is_ref, ptr_for_ref) {
2055                         write!(w, "{}", c_type).unwrap();
2056                         true
2057                 } else if self.crate_types.traits.get(&full_path).is_some() {
2058                         if is_ref && ptr_for_ref {
2059                                 write!(w, "*{} crate::{}", if is_mut { "mut" } else { "const" }, full_path).unwrap();
2060                         } else if is_ref {
2061                                 write!(w, "&{}crate::{}", if is_mut { "mut " } else { "" }, full_path).unwrap();
2062                         } else {
2063                                 write!(w, "crate::{}", full_path).unwrap();
2064                         }
2065                         true
2066                 } else if self.crate_types.opaques.get(&full_path).is_some() || self.crate_types.mirrored_enums.get(&full_path).is_some() {
2067                         if is_ref && ptr_for_ref {
2068                                 // ptr_for_ref implies we're returning the object, which we can't really do for
2069                                 // opaque or mirrored types without box'ing them, which is quite a waste, so return
2070                                 // the actual object itself (for opaque types we'll set the pointer to the actual
2071                                 // type and note that its a reference).
2072                                 write!(w, "crate::{}", full_path).unwrap();
2073                         } else if is_ref {
2074                                 write!(w, "&{}crate::{}", if is_mut { "mut " } else { "" }, full_path).unwrap();
2075                         } else {
2076                                 write!(w, "crate::{}", full_path).unwrap();
2077                         }
2078                         true
2079                 } else {
2080                         false
2081                 }
2082         }
2083         fn write_c_type_intern<W: std::io::Write>(&mut self, w: &mut W, t: &syn::Type, generics: Option<&GenericTypes>, is_ref: bool, is_mut: bool, ptr_for_ref: bool) -> bool {
2084                 match t {
2085                         syn::Type::Path(p) => {
2086                                 if p.qself.is_some() {
2087                                         return false;
2088                                 }
2089                                 if let Some(full_path) = self.maybe_resolve_path(&p.path, generics) {
2090                                         if self.is_known_container(&full_path, is_ref) || self.is_transparent_container(&full_path, is_ref) {
2091                                                 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);
2092                                         }
2093                                         if let Some(aliased_type) = self.crate_types.type_aliases.get(&full_path).cloned() {
2094                                                 return self.write_c_type_intern(w, &aliased_type, None, is_ref, is_mut, ptr_for_ref);
2095                                         }
2096                                 }
2097                                 self.write_c_path_intern(w, &p.path, generics, is_ref, is_mut, ptr_for_ref)
2098                         },
2099                         syn::Type::Reference(r) => {
2100                                 self.write_c_type_intern(w, &*r.elem, generics, true, r.mutability.is_some(), ptr_for_ref)
2101                         },
2102                         syn::Type::Array(a) => {
2103                                 if is_ref && is_mut {
2104                                         write!(w, "*mut [").unwrap();
2105                                         if !self.write_c_type_intern(w, &a.elem, generics, false, false, ptr_for_ref) { return false; }
2106                                 } else if is_ref {
2107                                         write!(w, "*const [").unwrap();
2108                                         if !self.write_c_type_intern(w, &a.elem, generics, false, false, ptr_for_ref) { return false; }
2109                                 } else {
2110                                         let mut typecheck = Vec::new();
2111                                         if !self.write_c_type_intern(&mut typecheck, &a.elem, generics, false, false, ptr_for_ref) { return false; }
2112                                         if typecheck[..] != ['u' as u8, '8' as u8] { return false; }
2113                                 }
2114                                 if let syn::Expr::Lit(l) = &a.len {
2115                                         if let syn::Lit::Int(i) = &l.lit {
2116                                                 if !is_ref {
2117                                                         if let Some(ty) = self.c_type_from_path(&format!("[u8; {}]", i.base10_digits()), false, ptr_for_ref) {
2118                                                                 write!(w, "{}", ty).unwrap();
2119                                                                 true
2120                                                         } else { false }
2121                                                 } else {
2122                                                         write!(w, "; {}]", i).unwrap();
2123                                                         true
2124                                                 }
2125                                         } else { false }
2126                                 } else { false }
2127                         }
2128                         syn::Type::Slice(s) => {
2129                                 if !is_ref || is_mut { return false; }
2130                                 if let syn::Type::Path(p) = &*s.elem {
2131                                         let resolved = self.resolve_path(&p.path, generics);
2132                                         if self.is_primitive(&resolved) {
2133                                                 write!(w, "{}::{}slice", Self::container_templ_path(), resolved).unwrap();
2134                                                 true
2135                                         } else { false }
2136                                 } else if let syn::Type::Reference(r) = &*s.elem {
2137                                         if let syn::Type::Path(p) = &*r.elem {
2138                                                 // Slices with "real types" inside are mapped as the equivalent non-ref Vec
2139                                                 let resolved = self.resolve_path(&p.path, generics);
2140                                                 let mangled_container = if let Some(ident) = self.crate_types.opaques.get(&resolved) {
2141                                                         format!("CVec_{}Z", ident)
2142                                                 } else if let Some(en) = self.crate_types.mirrored_enums.get(&resolved) {
2143                                                         format!("CVec_{}Z", en.ident)
2144                                                 } else if let Some(id) = p.path.get_ident() {
2145                                                         format!("CVec_{}Z", id)
2146                                                 } else { return false; };
2147                                                 write!(w, "{}::{}", Self::generated_container_path(), mangled_container).unwrap();
2148                                                 self.check_create_container(mangled_container, "Vec", vec![&*r.elem], generics, false)
2149                                         } else { false }
2150                                 } else if let syn::Type::Tuple(_) = &*s.elem {
2151                                         let mut args = syn::punctuated::Punctuated::new();
2152                                         args.push(syn::GenericArgument::Type((*s.elem).clone()));
2153                                         let mut segments = syn::punctuated::Punctuated::new();
2154                                         segments.push(syn::PathSegment {
2155                                                 ident: syn::Ident::new("Vec", Span::call_site()),
2156                                                 arguments: syn::PathArguments::AngleBracketed(syn::AngleBracketedGenericArguments {
2157                                                         colon2_token: None, lt_token: syn::Token![<](Span::call_site()), args, gt_token: syn::Token![>](Span::call_site()),
2158                                                 })
2159                                         });
2160                                         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)
2161                                 } else { false }
2162                         },
2163                         syn::Type::Tuple(t) => {
2164                                 if t.elems.len() == 0 {
2165                                         true
2166                                 } else {
2167                                         self.write_c_mangled_container_path(w, t.elems.iter().collect(), generics,
2168                                                 &format!("{}Tuple", t.elems.len()), is_ref, is_mut, ptr_for_ref)
2169                                 }
2170                         },
2171                         _ => false,
2172                 }
2173         }
2174         pub fn write_c_type<W: std::io::Write>(&mut self, w: &mut W, t: &syn::Type, generics: Option<&GenericTypes>, ptr_for_ref: bool) {
2175                 assert!(self.write_c_type_intern(w, t, generics, false, false, ptr_for_ref));
2176         }
2177         pub fn understood_c_path(&mut self, p: &syn::Path) -> bool {
2178                 if p.leading_colon.is_some() { return false; }
2179                 self.write_c_path_intern(&mut std::io::sink(), p, None, false, false, false)
2180         }
2181         pub fn understood_c_type(&mut self, t: &syn::Type, generics: Option<&GenericTypes>) -> bool {
2182                 self.write_c_type_intern(&mut std::io::sink(), t, generics, false, false, false)
2183         }
2184 }