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