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

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