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