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

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