_ 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)") || line.contains("This is not exported to bindings users") {
 138                                         return ExportStatus::NoExport;
 139                                 } else if line.contains("(C-not implementable)") {
 140                                         return ExportStatus::NotImplementable;
 141                                 }
 142                         },
 143                         _ => unimplemented!(),
 144                 }
 145         }
 146         ExportStatus::Export
 147 }
 148
 149 pub fn assert_simple_bound(bound: &syn::TraitBound) {
 150         if bound.paren_token.is_some() { unimplemented!(); }
 151         if let syn::TraitBoundModifier::Maybe(_) = bound.modifier { unimplemented!(); }
 152 }
 153
 154 /// Returns true if the enum will be mapped as an opaue (ie struct with a pointer to the underlying
 155 /// type), otherwise it is mapped into a transparent, C-compatible version of itself.
 156 pub fn is_enum_opaque(e: &syn::ItemEnum) -> bool {
 157         for var in e.variants.iter() {
 158                 if let syn::Fields::Named(fields) = &var.fields {
 159                         for field in fields.named.iter() {
 160                                 match export_status(&field.attrs) {
 161                                         ExportStatus::Export|ExportStatus::TestOnly => {},
 162                                         ExportStatus::NotImplementable => panic!("(C-not implementable) should only appear on traits!"),
 163                                         ExportStatus::NoExport => return true,
 164                                 }
 165                         }
 166                 } else if let syn::Fields::Unnamed(fields) = &var.fields {
 167                         for field in fields.unnamed.iter() {
 168                                 match export_status(&field.attrs) {
 169                                         ExportStatus::Export|ExportStatus::TestOnly => {},
 170                                         ExportStatus::NotImplementable => panic!("(C-not implementable) should only appear on traits!"),
 171                                         ExportStatus::NoExport => return true,
 172                                 }
 173                         }
 174                 }
 175         }
 176         false
 177 }
 178
 179 /// A stack of sets of generic resolutions.
 180 ///
 181 /// This tracks the template parameters for a function, struct, or trait, allowing resolution into
 182 /// a concrete type. By pushing a new context onto the stack, this can track a function's template
 183 /// parameters inside of a generic struct or trait.
 184 ///
 185 /// It maps both direct types as well as Deref<Target = X>, mapping them via the provided
 186 /// TypeResolver's resolve_path function (ie traits map to the concrete jump table, structs to the
 187 /// concrete C container struct, etc).
 188 #[must_use]
 189 pub struct GenericTypes<'a, 'b> {
 190         self_ty: Option<String>,
 191         parent: Option<&'b GenericTypes<'b, 'b>>,
 192         typed_generics: HashMap<&'a syn::Ident, String>,
 193         default_generics: HashMap<&'a syn::Ident, (syn::Type, syn::Type, syn::Type)>,
 194 }
 195 impl<'a, 'p: 'a> GenericTypes<'a, 'p> {
 196         pub fn new(self_ty: Option<String>) -> Self {
 197                 Self { self_ty, parent: None, typed_generics: HashMap::new(), default_generics: HashMap::new(), }
 198         }
 199
 200         /// push a new context onto the stack, allowing for a new set of generics to be learned which
 201         /// will override any lower contexts, but which will still fall back to resoltion via lower
 202         /// contexts.
 203         pub fn push_ctx<'c>(&'c self) -> GenericTypes<'a, 'c> {
 204                 GenericTypes { self_ty: None, parent: Some(self), typed_generics: HashMap::new(), default_generics: HashMap::new(), }
 205         }
 206
 207         /// Learn the generics in generics in the current context, given a TypeResolver.
 208         pub fn learn_generics_with_impls<'b, 'c>(&mut self, generics: &'a syn::Generics, impld_generics: &'a syn::PathArguments, types: &'b TypeResolver<'a, 'c>) -> bool {
 209                 let mut new_typed_generics = HashMap::new();
 210                 // First learn simple generics...
 211                 for (idx, generic) in generics.params.iter().enumerate() {
 212                         match generic {
 213                                 syn::GenericParam::Type(type_param) => {
 214                                         let mut non_lifetimes_processed = false;
 215                                         'bound_loop: for bound in type_param.bounds.iter() {
 216                                                 if let syn::TypeParamBound::Trait(trait_bound) = bound {
 217                                                         if let Some(ident) = single_ident_generic_path_to_ident(&trait_bound.path) {
 218                                                                 match &format!("{}", ident) as &str { "Send" => continue, "Sync" => continue, "Sized" => continue, _ => {} }
 219                                                         }
 220                                                         if path_matches_nongeneric(&trait_bound.path, &["core", "clone", "Clone"]) { continue; }
 221
 222                                                         assert_simple_bound(&trait_bound);
 223                                                         if let Some(path) = types.maybe_resolve_path(&trait_bound.path, None) {
 224                                                                 if types.skip_path(&path) { continue; }
 225                                                                 if path == "Sized" { continue; }
 226                                                                 if non_lifetimes_processed { return false; }
 227                                                                 non_lifetimes_processed = true;
 228                                                                 if path != "std::ops::Deref" && path != "core::ops::Deref" {
 229                                                                         let p = string_path_to_syn_path(&path);
 230                                                                         let ref_ty = parse_quote!(&#p);
 231                                                                         let mut_ref_ty = parse_quote!(&mut #p);
 232                                                                         self.default_generics.insert(&type_param.ident, (syn::Type::Path(syn::TypePath { qself: None, path: p }), ref_ty, mut_ref_ty));
 233                                                                         new_typed_generics.insert(&type_param.ident, Some(path));
 234                                                                 } else {
 235                                                                         // If we're templated on Deref<Target = ConcreteThing>, store
 236                                                                         // the reference type in `default_generics` which handles full
 237                                                                         // types and not just paths.
 238                                                                         if let syn::PathArguments::AngleBracketed(ref args) =
 239                                                                                         trait_bound.path.segments[0].arguments {
 240                                                                                 assert_eq!(trait_bound.path.segments.len(), 1);
 241                                                                                 for subargument in args.args.iter() {
 242                                                                                         match subargument {
 243                                                                                                 syn::GenericArgument::Lifetime(_) => {},
 244                                                                                                 syn::GenericArgument::Binding(ref b) => {
 245                                                                                                         if &format!("{}", b.ident) != "Target" { return false; }
 246                                                                                                         let default = &b.ty;
 247                                                                                                         self.default_generics.insert(&type_param.ident, (parse_quote!(&#default), parse_quote!(&#default), parse_quote!(&mut #default)));
 248                                                                                                         break 'bound_loop;
 249                                                                                                 },
 250                                                                                                 _ => unimplemented!(),
 251                                                                                         }
 252                                                                                 }
 253                                                                         } else {
 254                                                                                 new_typed_generics.insert(&type_param.ident, None);
 255                                                                         }
 256                                                                 }
 257                                                         }
 258                                                 }
 259                                         }
 260                                         if let Some(default) = type_param.default.as_ref() {
 261                                                 assert!(type_param.bounds.is_empty());
 262                                                 self.default_generics.insert(&type_param.ident, (default.clone(), parse_quote!(&#default), parse_quote!(&mut #default)));
 263                                         } else if type_param.bounds.is_empty() {
 264                                                 if let syn::PathArguments::AngleBracketed(args) = impld_generics {
 265                                                         match &args.args[idx] {
 266                                                                 syn::GenericArgument::Type(ty) => {
 267                                                                         self.default_generics.insert(&type_param.ident, (ty.clone(), parse_quote!(&#ty), parse_quote!(&mut #ty)));
 268                                                                 }
 269                                                                 _ => unimplemented!(),
 270                                                         }
 271                                                 }
 272                                         }
 273                                 },
 274                                 _ => {},
 275                         }
 276                 }
 277                 // Then find generics where we are required to pass a Deref<Target=X> and pretend its just X.
 278                 if let Some(wh) = &generics.where_clause {
 279                         for pred in wh.predicates.iter() {
 280                                 if let syn::WherePredicate::Type(t) = pred {
 281                                         if let syn::Type::Path(p) = &t.bounded_ty {
 282                                                 if first_seg_self(&t.bounded_ty).is_some() && p.path.segments.len() == 1 { continue; }
 283                                                 if p.qself.is_some() { return false; }
 284                                                 if p.path.leading_colon.is_some() { return false; }
 285                                                 let mut p_iter = p.path.segments.iter();
 286                                                 let p_ident = &p_iter.next().unwrap().ident;
 287                                                 if let Some(gen) = new_typed_generics.get_mut(p_ident) {
 288                                                         if gen.is_some() { return false; }
 289                                                         if &format!("{}", p_iter.next().unwrap().ident) != "Target" {return false; }
 290
 291                                                         let mut non_lifetimes_processed = false;
 292                                                         for bound in t.bounds.iter() {
 293                                                                 if let syn::TypeParamBound::Trait(trait_bound) = bound {
 294                                                                         if let Some(id) = trait_bound.path.get_ident() {
 295                                                                                 if format!("{}", id) == "Sized" { continue; }
 296                                                                         }
 297                                                                         if non_lifetimes_processed { return false; }
 298                                                                         non_lifetimes_processed = true;
 299                                                                         assert_simple_bound(&trait_bound);
 300                                                                         let resolved = types.resolve_path(&trait_bound.path, None);
 301                                                                         let ty = syn::Type::Path(syn::TypePath {
 302                                                                                 qself: None, path: string_path_to_syn_path(&resolved)
 303                                                                         });
 304                                                                         let ref_ty = parse_quote!(&#ty);
 305                                                                         let mut_ref_ty = parse_quote!(&mut #ty);
 306                                                                         if types.crate_types.traits.get(&resolved).is_some() {
 307                                                                                 self.default_generics.insert(p_ident, (ty, ref_ty, mut_ref_ty));
 308                                                                         } else {
 309                                                                                 self.default_generics.insert(p_ident, (ref_ty.clone(), ref_ty, mut_ref_ty));
 310                                                                         }
 311
 312                                                                         *gen = Some(resolved);
 313                                                                 }
 314                                                         }
 315                                                 } else { return false; }
 316                                         } else { return false; }
 317                                 }
 318                         }
 319                 }
 320                 for (key, value) in new_typed_generics.drain() {
 321                         if let Some(v) = value {
 322                                 assert!(self.typed_generics.insert(key, v).is_none());
 323                         } else { return false; }
 324                 }
 325                 true
 326         }
 327
 328         /// Learn the generics in generics in the current context, given a TypeResolver.
 329         pub fn learn_generics<'b, 'c>(&mut self, generics: &'a syn::Generics, types: &'b TypeResolver<'a, 'c>) -> bool {
 330                 self.learn_generics_with_impls(generics, &syn::PathArguments::None, types)
 331         }
 332
 333         /// Learn the associated types from the trait in the current context.
 334         pub fn learn_associated_types<'b, 'c>(&mut self, t: &'a syn::ItemTrait, types: &'b TypeResolver<'a, 'c>) {
 335                 for item in t.items.iter() {
 336                         match item {
 337                                 &syn::TraitItem::Type(ref t) => {
 338                                         if t.default.is_some() || t.generics.lt_token.is_some() { unimplemented!(); }
 339                                         let mut bounds_iter = t.bounds.iter();
 340                                         loop {
 341                                                 match bounds_iter.next().unwrap() {
 342                                                         syn::TypeParamBound::Trait(tr) => {
 343                                                                 assert_simple_bound(&tr);
 344                                                                 if let Some(path) = types.maybe_resolve_path(&tr.path, None) {
 345                                                                         if types.skip_path(&path) { continue; }
 346                                                                         // In general we handle Deref<Target=X> as if it were just X (and
 347                                                                         // implement Deref<Target=Self> for relevant types). We don't
 348                                                                         // bother to implement it for associated types, however, so we just
 349                                                                         // ignore such bounds.
 350                                                                         if path != "std::ops::Deref" && path != "core::ops::Deref" {
 351                                                                                 self.typed_generics.insert(&t.ident, path);
 352                                                                         }
 353                                                                 } else { unimplemented!(); }
 354                                                                 for bound in bounds_iter {
 355                                                                         if let syn::TypeParamBound::Trait(t) = bound {
 356                                                                                 // We only allow for `?Sized` here.
 357                                                                                 assert_eq!(t.path.segments.len(), 1);
 358                                                                                 assert_eq!(format!("{}", t.path.segments[0].ident), "Sized");
 359                                                                         }
 360                                                                 }
 361                                                                 break;
 362                                                         },
 363                                                         syn::TypeParamBound::Lifetime(_) => {},
 364                                                 }
 365                                         }
 366                                 },
 367                                 _ => {},
 368                         }
 369                 }
 370         }
 371
 372         /// Attempt to resolve a Path as a generic parameter and return the full path. as both a string
 373         /// and syn::Path.
 374         pub fn maybe_resolve_path<'b>(&'b self, path: &syn::Path) -> Option<&'b String> {
 375                 if let Some(ident) = path.get_ident() {
 376                         if let Some(ty) = &self.self_ty {
 377                                 if format!("{}", ident) == "Self" {
 378                                         return Some(&ty);
 379                                 }
 380                         }
 381                         if let Some(res) = self.typed_generics.get(ident) {
 382                                 return Some(res);
 383                         }
 384                 } else {
 385                         // Associated types are usually specified as "Self::Generic", so we check for that
 386                         // explicitly here.
 387                         let mut it = path.segments.iter();
 388                         if path.segments.len() == 2 && format!("{}", it.next().unwrap().ident) == "Self" {
 389                                 let ident = &it.next().unwrap().ident;
 390                                 if let Some(res) = self.typed_generics.get(ident) {
 391                                         return Some(res);
 392                                 }
 393                         }
 394                 }
 395                 if let Some(parent) = self.parent {
 396                         parent.maybe_resolve_path(path)
 397                 } else {
 398                         None
 399                 }
 400         }
 401 }
 402
 403 pub trait ResolveType<'a> { fn resolve_type(&'a self, ty: &'a syn::Type) -> &'a syn::Type; }
 404 impl<'a, 'b, 'c: 'a + 'b> ResolveType<'c> for Option<&GenericTypes<'a, 'b>> {
 405         fn resolve_type(&'c self, ty: &'c syn::Type) -> &'c syn::Type {
 406                 if let Some(us) = self {
 407                         match ty {
 408                                 syn::Type::Path(p) => {
 409                                         if let Some(ident) = p.path.get_ident() {
 410                                                 if let Some((ty, _, _)) = us.default_generics.get(ident) {
 411                                                         return self.resolve_type(ty);
 412                                                 }
 413                                         }
 414                                 },
 415                                 syn::Type::Reference(syn::TypeReference { elem, mutability, .. }) => {
 416                                         if let syn::Type::Path(p) = &**elem {
 417                                                 if let Some(ident) = p.path.get_ident() {
 418                                                         if let Some((_, refty, mut_ref_ty)) = us.default_generics.get(ident) {
 419                                                                 if mutability.is_some() {
 420                                                                         return self.resolve_type(mut_ref_ty);
 421                                                                 } else {
 422                                                                         return self.resolve_type(refty);
 423                                                                 }
 424                                                         }
 425                                                 }
 426                                         }
 427                                 }
 428                                 _ => {},
 429                         }
 430                         us.parent.resolve_type(ty)
 431                 } else { ty }
 432         }
 433 }
 434
 435 #[derive(Clone, PartialEq)]
 436 // The type of declaration and the object itself
 437 pub enum DeclType<'a> {
 438         MirroredEnum,
 439         Trait(&'a syn::ItemTrait),
 440         StructImported { generics: &'a syn::Generics  },
 441         StructIgnored,
 442         EnumIgnored { generics: &'a syn::Generics },
 443 }
 444
 445 pub struct ImportResolver<'mod_lifetime, 'crate_lft: 'mod_lifetime> {
 446         pub crate_name: &'mod_lifetime str,
 447         library: &'crate_lft FullLibraryAST,
 448         module_path: &'mod_lifetime str,
 449         imports: HashMap<syn::Ident, (String, syn::Path)>,
 450         declared: HashMap<syn::Ident, DeclType<'crate_lft>>,
 451         priv_modules: HashSet<syn::Ident>,
 452 }
 453 impl<'mod_lifetime, 'crate_lft: 'mod_lifetime> ImportResolver<'mod_lifetime, 'crate_lft> {
 454         fn walk_use_intern<F: FnMut(syn::Ident, (String, syn::Path))>(
 455                 crate_name: &str, module_path: &str, dependencies: &HashSet<syn::Ident>, u: &syn::UseTree,
 456                 partial_path: &str,
 457                 mut path: syn::punctuated::Punctuated<syn::PathSegment, syn::token::Colon2>, handle_use: &mut F
 458         ) {
 459                 let new_path;
 460                 macro_rules! push_path {
 461                         ($ident: expr, $path_suffix: expr) => {
 462                                 if partial_path == "" && format!("{}", $ident) == "super" {
 463                                         let mut mod_iter = module_path.rsplitn(2, "::");
 464                                         mod_iter.next().unwrap();
 465                                         let super_mod = mod_iter.next().unwrap();
 466                                         new_path = format!("{}{}", super_mod, $path_suffix);
 467                                         assert_eq!(path.len(), 0);
 468                                         for module in super_mod.split("::") {
 469                                                 path.push(syn::PathSegment { ident: syn::Ident::new(module, Span::call_site()), arguments: syn::PathArguments::None });
 470                                         }
 471                                 } else if partial_path == "" && format!("{}", $ident) == "self" {
 472                                         new_path = format!("{}{}", module_path, $path_suffix);
 473                                         for module in module_path.split("::") {
 474                                                 path.push(syn::PathSegment { ident: syn::Ident::new(module, Span::call_site()), arguments: syn::PathArguments::None });
 475                                         }
 476                                 } else if partial_path == "" && format!("{}", $ident) == "crate" {
 477                                         new_path = format!("{}{}", crate_name, $path_suffix);
 478                                         let crate_name_ident = format_ident!("{}", crate_name);
 479                                         path.push(parse_quote!(#crate_name_ident));
 480                                 } else if partial_path == "" && !dependencies.contains(&$ident) {
 481                                         new_path = format!("{}::{}{}", module_path, $ident, $path_suffix);
 482                                         for module in module_path.split("::") {
 483                                                 path.push(syn::PathSegment { ident: syn::Ident::new(module, Span::call_site()), arguments: syn::PathArguments::None });
 484                                         }
 485                                         let ident_str = format_ident!("{}", $ident);
 486                                         path.push(parse_quote!(#ident_str));
 487                                 } else if format!("{}", $ident) == "self" {
 488                                         let mut path_iter = partial_path.rsplitn(2, "::");
 489                                         path_iter.next().unwrap();
 490                                         new_path = path_iter.next().unwrap().to_owned();
 491                                 } else {
 492                                         new_path = format!("{}{}{}", partial_path, $ident, $path_suffix);
 493                                 }
 494                                 let ident = &$ident;
 495                                 path.push(parse_quote!(#ident));
 496                         }
 497                 }
 498                 match u {
 499                         syn::UseTree::Path(p) => {
 500                                 push_path!(p.ident, "::");
 501                                 Self::walk_use_intern(crate_name, module_path, dependencies, &p.tree, &new_path, path, handle_use);
 502                         },
 503                         syn::UseTree::Name(n) => {
 504                                 push_path!(n.ident, "");
 505                                 let imported_ident = syn::Ident::new(new_path.rsplitn(2, "::").next().unwrap(), Span::call_site());
 506                                 handle_use(imported_ident, (new_path, syn::Path { leading_colon: Some(syn::Token![::](Span::call_site())), segments: path }));
 507                         },
 508                         syn::UseTree::Group(g) => {
 509                                 for i in g.items.iter() {
 510                                         Self::walk_use_intern(crate_name, module_path, dependencies, i, partial_path, path.clone(), handle_use);
 511                                 }
 512                         },
 513                         syn::UseTree::Rename(r) => {
 514                                 push_path!(r.ident, "");
 515                                 handle_use(r.rename.clone(), (new_path, syn::Path { leading_colon: Some(syn::Token![::](Span::call_site())), segments: path }));
 516                         },
 517                         syn::UseTree::Glob(_) => {
 518                                 eprintln!("Ignoring * use for {} - this may result in resolution failures", partial_path);
 519                         },
 520                 }
 521         }
 522
 523         fn process_use_intern(crate_name: &str, module_path: &str, dependencies: &HashSet<syn::Ident>,
 524                 imports: &mut HashMap<syn::Ident, (String, syn::Path)>, u: &syn::UseTree, partial_path: &str,
 525                 path: syn::punctuated::Punctuated<syn::PathSegment, syn::token::Colon2>
 526         ) {
 527                 Self::walk_use_intern(crate_name, module_path, dependencies, u, partial_path, path,
 528                         &mut |k, v| { imports.insert(k, v); });
 529         }
 530
 531         fn process_use(crate_name: &str, module_path: &str, dependencies: &HashSet<syn::Ident>, imports: &mut HashMap<syn::Ident, (String, syn::Path)>, u: &syn::ItemUse) {
 532                 if u.leading_colon.is_some() { eprintln!("Ignoring leading-colon use!"); return; }
 533                 Self::process_use_intern(crate_name, module_path, dependencies, imports, &u.tree, "", syn::punctuated::Punctuated::new());
 534         }
 535
 536         fn insert_primitive(imports: &mut HashMap<syn::Ident, (String, syn::Path)>, id: &str) {
 537                 let ident = format_ident!("{}", id);
 538                 let path = parse_quote!(#ident);
 539                 imports.insert(ident, (id.to_owned(), path));
 540         }
 541
 542         pub fn new(crate_name: &'mod_lifetime str, library: &'crate_lft FullLibraryAST, module_path: &'mod_lifetime str, contents: &'crate_lft [syn::Item]) -> Self {
 543                 Self::from_borrowed_items(crate_name, library, module_path, &contents.iter().map(|a| a).collect::<Vec<_>>())
 544         }
 545         pub fn from_borrowed_items(crate_name: &'mod_lifetime str, library: &'crate_lft FullLibraryAST, module_path: &'mod_lifetime str, contents: &[&'crate_lft syn::Item]) -> Self {
 546                 let mut imports = HashMap::new();
 547                 // Add primitives to the "imports" list:
 548                 Self::insert_primitive(&mut imports, "bool");
 549                 Self::insert_primitive(&mut imports, "u128");
 550                 Self::insert_primitive(&mut imports, "i64");
 551                 Self::insert_primitive(&mut imports, "f64");
 552                 Self::insert_primitive(&mut imports, "u64");
 553                 Self::insert_primitive(&mut imports, "u32");
 554                 Self::insert_primitive(&mut imports, "u16");
 555                 Self::insert_primitive(&mut imports, "u8");
 556                 Self::insert_primitive(&mut imports, "usize");
 557                 Self::insert_primitive(&mut imports, "str");
 558                 Self::insert_primitive(&mut imports, "String");
 559
 560                 // These are here to allow us to print native Rust types in trait fn impls even if we don't
 561                 // have C mappings:
 562                 Self::insert_primitive(&mut imports, "Result");
 563                 Self::insert_primitive(&mut imports, "Vec");
 564                 Self::insert_primitive(&mut imports, "Option");
 565
 566                 let mut declared = HashMap::new();
 567                 let mut priv_modules = HashSet::new();
 568
 569                 for item in contents.iter() {
 570                         match item {
 571                                 syn::Item::Use(u) => Self::process_use(crate_name, module_path, &library.dependencies, &mut imports, &u),
 572                                 syn::Item::Struct(s) => {
 573                                         if let syn::Visibility::Public(_) = s.vis {
 574                                                 match export_status(&s.attrs) {
 575                                                         ExportStatus::Export => { declared.insert(s.ident.clone(), DeclType::StructImported { generics: &s.generics }); },
 576                                                         ExportStatus::NoExport => { declared.insert(s.ident.clone(), DeclType::StructIgnored); },
 577                                                         ExportStatus::TestOnly => continue,
 578                                                         ExportStatus::NotImplementable => panic!("(C-not implementable) should only appear on traits!"),
 579                                                 }
 580                                         }
 581                                 },
 582                                 syn::Item::Type(t) if export_status(&t.attrs) == ExportStatus::Export => {
 583                                         if let syn::Visibility::Public(_) = t.vis {
 584                                                 declared.insert(t.ident.clone(), DeclType::StructImported { generics: &t.generics });
 585                                         }
 586                                 },
 587                                 syn::Item::Enum(e) => {
 588                                         if let syn::Visibility::Public(_) = e.vis {
 589                                                 match export_status(&e.attrs) {
 590                                                         ExportStatus::Export if is_enum_opaque(e) => { declared.insert(e.ident.clone(), DeclType::EnumIgnored { generics: &e.generics }); },
 591                                                         ExportStatus::Export => { declared.insert(e.ident.clone(), DeclType::MirroredEnum); },
 592                                                         ExportStatus::NotImplementable => panic!("(C-not implementable) should only appear on traits!"),
 593                                                         _ => continue,
 594                                                 }
 595                                         }
 596                                 },
 597                                 syn::Item::Trait(t) => {
 598                                         if let syn::Visibility::Public(_) = t.vis {
 599                                                 declared.insert(t.ident.clone(), DeclType::Trait(t));
 600                                         }
 601                                 },
 602                                 syn::Item::Mod(m) => {
 603                                         priv_modules.insert(m.ident.clone());
 604                                 },
 605                                 _ => {},
 606                         }
 607                 }
 608
 609                 Self { crate_name, library, module_path, imports, declared, priv_modules }
 610         }
 611
 612         pub fn maybe_resolve_declared(&self, id: &syn::Ident) -> Option<&DeclType<'crate_lft>> {
 613                 self.declared.get(id)
 614         }
 615
 616         pub fn maybe_resolve_ident(&self, id: &syn::Ident) -> Option<String> {
 617                 if let Some((imp, _)) = self.imports.get(id) {
 618                         Some(imp.clone())
 619                 } else if self.declared.get(id).is_some() {
 620                         Some(self.module_path.to_string() + "::" + &format!("{}", id))
 621                 } else { None }
 622         }
 623
 624         fn maybe_resolve_imported_path(&self, p: &syn::Path, generics: Option<&GenericTypes>) -> Option<String> {
 625                 if let Some(gen_types) = generics {
 626                         if let Some(resp) = gen_types.maybe_resolve_path(p) {
 627                                 return Some(resp.clone());
 628                         }
 629                 }
 630
 631                 if p.leading_colon.is_some() {
 632                         let mut res: String = p.segments.iter().enumerate().map(|(idx, seg)| {
 633                                 format!("{}{}", if idx == 0 { "" } else { "::" }, seg.ident)
 634                         }).collect();
 635                         let firstseg = p.segments.iter().next().unwrap();
 636                         if !self.library.dependencies.contains(&firstseg.ident) {
 637                                 res = self.crate_name.to_owned() + "::" + &res;
 638                         }
 639                         Some(res)
 640                 } else if let Some(id) = p.get_ident() {
 641                         self.maybe_resolve_ident(id)
 642                 } else {
 643                         if p.segments.len() == 1 {
 644                                 let seg = p.segments.iter().next().unwrap();
 645                                 return self.maybe_resolve_ident(&seg.ident);
 646                         }
 647                         let mut seg_iter = p.segments.iter();
 648                         let first_seg = seg_iter.next().unwrap();
 649                         let remaining: String = seg_iter.map(|seg| {
 650                                 format!("::{}", seg.ident)
 651                         }).collect();
 652                         let first_seg_str = format!("{}", first_seg.ident);
 653                         if let Some((imp, _)) = self.imports.get(&first_seg.ident) {
 654                                 if remaining != "" {
 655                                         Some(imp.clone() + &remaining)
 656                                 } else {
 657                                         Some(imp.clone())
 658                                 }
 659                         } else if let Some(_) = self.priv_modules.get(&first_seg.ident) {
 660                                 Some(format!("{}::{}{}", self.module_path, first_seg.ident, remaining))
 661                         } else if first_seg_is_stdlib(&first_seg_str) || self.library.dependencies.contains(&first_seg.ident) {
 662                                 Some(first_seg_str + &remaining)
 663                         } else if first_seg_str == "crate" {
 664                                 Some(self.crate_name.to_owned() + &remaining)
 665                         } else { None }
 666                 }
 667         }
 668
 669         pub fn maybe_resolve_path(&self, p: &syn::Path, generics: Option<&GenericTypes>) -> Option<String> {
 670                 self.maybe_resolve_imported_path(p, generics).map(|mut path| {
 671                         loop {
 672                                 // Now that we've resolved the path to the path as-imported, check whether the path
 673                                 // is actually a pub(.*) use statement and map it to the real path.
 674                                 let path_tmp = path.clone();
 675                                 let crate_name = path_tmp.splitn(2, "::").next().unwrap();
 676                                 let mut module_riter = path_tmp.rsplitn(2, "::");
 677                                 let obj = module_riter.next().unwrap();
 678                                 if let Some(module_path) = module_riter.next() {
 679                                         if let Some(m) = self.library.modules.get(module_path) {
 680                                                 for item in m.items.iter() {
 681                                                         if let syn::Item::Use(syn::ItemUse { vis, tree, .. }) = item {
 682                                                                 match vis {
 683                                                                         syn::Visibility::Public(_)|
 684                                                                         syn::Visibility::Crate(_)|
 685                                                                         syn::Visibility::Restricted(_) => {
 686                                                                                 Self::walk_use_intern(crate_name, module_path,
 687                                                                                         &self.library.dependencies, tree, "",
 688                                                                                         syn::punctuated::Punctuated::new(), &mut |ident, (use_path, _)| {
 689                                                                                                 if format!("{}", ident) == obj {
 690                                                                                                         path = use_path;
 691                                                                                                 }
 692                                                                                 });
 693                                                                         },
 694                                                                         syn::Visibility::Inherited => {},
 695                                                                 }
 696                                                         }
 697                                                 }
 698                                         }
 699                                 }
 700                                 break;
 701                         }
 702                         path
 703                 })
 704         }
 705
 706         /// Map all the Paths in a Type into absolute paths given a set of imports (generated via process_use_intern)
 707         pub fn resolve_imported_refs(&self, mut ty: syn::Type) -> syn::Type {
 708                 match &mut ty {
 709                         syn::Type::Path(p) => {
 710                                 if p.path.segments.len() != 1 { unimplemented!(); }
 711                                 let mut args = p.path.segments[0].arguments.clone();
 712                                 if let syn::PathArguments::AngleBracketed(ref mut generics) = &mut args {
 713                                         for arg in generics.args.iter_mut() {
 714                                                 if let syn::GenericArgument::Type(ref mut t) = arg {
 715                                                         *t = self.resolve_imported_refs(t.clone());
 716                                                 }
 717                                         }
 718                                 }
 719                                 if let Some((_, newpath)) = self.imports.get(single_ident_generic_path_to_ident(&p.path).unwrap()) {
 720                                         p.path = newpath.clone();
 721                                 }
 722                                 p.path.segments[0].arguments = args;
 723                         },
 724                         syn::Type::Reference(r) => {
 725                                 r.elem = Box::new(self.resolve_imported_refs((*r.elem).clone()));
 726                         },
 727                         syn::Type::Slice(s) => {
 728                                 s.elem = Box::new(self.resolve_imported_refs((*s.elem).clone()));
 729                         },
 730                         syn::Type::Tuple(t) => {
 731                                 for e in t.elems.iter_mut() {
 732                                         *e = self.resolve_imported_refs(e.clone());
 733                                 }
 734                         },
 735                         _ => unimplemented!(),
 736                 }
 737                 ty
 738         }
 739 }
 740
 741 // templates_defined is walked to write the C++ header, so if we use the default hashing it get
 742 // reordered on each genbindings run. Instead, we use SipHasher (which defaults to 0-keys) so that
 743 // the sorting is stable across runs. It is deprecated, but the "replacement" doesn't actually
 744 // accomplish the same goals, so we just ignore it.
 745 #[allow(deprecated)]
 746 pub type NonRandomHash = hash::BuildHasherDefault<hash::SipHasher>;
 747
 748 /// A public module
 749 pub struct ASTModule {
 750         pub attrs: Vec<syn::Attribute>,
 751         pub items: Vec<syn::Item>,
 752         pub submods: Vec<String>,
 753 }
 754 /// A struct containing the syn::File AST for each file in the crate.
 755 pub struct FullLibraryAST {
 756         pub modules: HashMap<String, ASTModule, NonRandomHash>,
 757         pub dependencies: HashSet<syn::Ident>,
 758 }
 759 impl FullLibraryAST {
 760         fn load_module(&mut self, module: String, attrs: Vec<syn::Attribute>, mut items: Vec<syn::Item>) {
 761                 let mut non_mod_items = Vec::with_capacity(items.len());
 762                 let mut submods = Vec::with_capacity(items.len());
 763                 for item in items.drain(..) {
 764                         match item {
 765                                 syn::Item::Mod(m) if m.content.is_some() => {
 766                                         if export_status(&m.attrs) == ExportStatus::Export {
 767                                                 if let syn::Visibility::Public(_) = m.vis {
 768                                                         let modident = format!("{}", m.ident);
 769                                                         let modname = if module != "" {
 770                                                                 module.clone() + "::" + &modident
 771                                                         } else {
 772                                                                 self.dependencies.insert(m.ident);
 773                                                                 modident.clone()
 774                                                         };
 775                                                         self.load_module(modname, m.attrs, m.content.unwrap().1);
 776                                                         submods.push(modident);
 777                                                 } else {
 778                                                         non_mod_items.push(syn::Item::Mod(m));
 779                                                 }
 780                                         }
 781                                 },
 782                                 syn::Item::Mod(_) => panic!("--pretty=expanded output should never have non-body modules"),
 783                                 syn::Item::ExternCrate(c) => {
 784                                         if export_status(&c.attrs) == ExportStatus::Export {
 785                                                 self.dependencies.insert(c.ident);
 786                                         }
 787                                 },
 788                                 _ => { non_mod_items.push(item); }
 789                         }
 790                 }
 791                 self.modules.insert(module, ASTModule { attrs, items: non_mod_items, submods });
 792         }
 793
 794         pub fn load_lib(lib: syn::File) -> Self {
 795                 assert_eq!(export_status(&lib.attrs), ExportStatus::Export);
 796                 let mut res = Self { modules: HashMap::default(), dependencies: HashSet::new() };
 797                 res.load_module("".to_owned(), lib.attrs, lib.items);
 798                 res
 799         }
 800 }
 801
 802 /// List of manually-generated types which are clonable
 803 fn initial_clonable_types() -> HashSet<String> {
 804         let mut res = HashSet::new();
 805         res.insert("crate::c_types::U5".to_owned());
 806         res.insert("crate::c_types::U128".to_owned());
 807         res.insert("crate::c_types::FourBytes".to_owned());
 808         res.insert("crate::c_types::TwelveBytes".to_owned());
 809         res.insert("crate::c_types::SixteenBytes".to_owned());
 810         res.insert("crate::c_types::TwentyBytes".to_owned());
 811         res.insert("crate::c_types::ThirtyTwoBytes".to_owned());
 812         res.insert("crate::c_types::EightU16s".to_owned());
 813         res.insert("crate::c_types::SecretKey".to_owned());
 814         res.insert("crate::c_types::PublicKey".to_owned());
 815         res.insert("crate::c_types::Transaction".to_owned());
 816         res.insert("crate::c_types::Witness".to_owned());
 817         res.insert("crate::c_types::WitnessVersion".to_owned());
 818         res.insert("crate::c_types::TxIn".to_owned());
 819         res.insert("crate::c_types::TxOut".to_owned());
 820         res.insert("crate::c_types::Signature".to_owned());
 821         res.insert("crate::c_types::RecoverableSignature".to_owned());
 822         res.insert("crate::c_types::BigEndianScalar".to_owned());
 823         res.insert("crate::c_types::Bech32Error".to_owned());
 824         res.insert("crate::c_types::Secp256k1Error".to_owned());
 825         res.insert("crate::c_types::IOError".to_owned());
 826         res.insert("crate::c_types::Error".to_owned());
 827         res.insert("crate::c_types::Str".to_owned());
 828
 829         // Because some types are manually-mapped to CVec_u8Z we may end up checking if its clonable
 830         // before we ever get to constructing the type fully via
 831         // `write_c_mangled_container_path_intern` (which will add it here too), so we have to manually
 832         // add it on startup.
 833         res.insert("crate::c_types::derived::CVec_u8Z".to_owned());
 834         res
 835 }
 836
 837 /// Top-level struct tracking everything which has been defined while walking the crate.
 838 pub struct CrateTypes<'a> {
 839         /// This may contain structs or enums, but only when either is mapped as
 840         /// struct X { inner: *mut originalX, .. }
 841         pub opaques: HashMap<String, (&'a syn::Ident, &'a syn::Generics)>,
 842         /// structs that weren't exposed
 843         pub priv_structs: HashMap<String, &'a syn::Generics>,
 844         /// Enums which are mapped as C enums with conversion functions
 845         pub mirrored_enums: HashMap<String, &'a syn::ItemEnum>,
 846         /// Traits which are mapped as a pointer + jump table
 847         pub traits: HashMap<String, &'a syn::ItemTrait>,
 848         /// Aliases from paths to some other Type
 849         pub type_aliases: HashMap<String, syn::Type>,
 850         /// Value is an alias to Key (maybe with some generics)
 851         pub reverse_alias_map: HashMap<String, Vec<(String, syn::PathArguments)>>,
 852         /// Template continer types defined, map from mangled type name -> whether a destructor fn
 853         /// exists.
 854         ///
 855         /// This is used at the end of processing to make C++ wrapper classes
 856         pub templates_defined: RefCell<HashMap<String, bool, NonRandomHash>>,
 857         /// The output file for any created template container types, written to as we find new
 858         /// template containers which need to be defined.
 859         template_file: RefCell<&'a mut File>,
 860         /// Set of containers which are clonable
 861         clonable_types: RefCell<HashSet<String>>,
 862         /// Key impls Value
 863         pub trait_impls: HashMap<String, Vec<String>>,
 864         /// Value impls Key
 865         pub traits_impld: HashMap<String, Vec<String>>,
 866         /// The full set of modules in the crate(s)
 867         pub lib_ast: &'a FullLibraryAST,
 868 }
 869
 870 impl<'a> CrateTypes<'a> {
 871         pub fn new(template_file: &'a mut File, libast: &'a FullLibraryAST) -> Self {
 872                 CrateTypes {
 873                         opaques: HashMap::new(), mirrored_enums: HashMap::new(), traits: HashMap::new(),
 874                         type_aliases: HashMap::new(), reverse_alias_map: HashMap::new(),
 875                         templates_defined: RefCell::new(HashMap::default()), priv_structs: HashMap::new(),
 876                         clonable_types: RefCell::new(initial_clonable_types()),
 877                         trait_impls: HashMap::new(), traits_impld: HashMap::new(),
 878                         template_file: RefCell::new(template_file), lib_ast: &libast,
 879                 }
 880         }
 881         pub fn set_clonable(&self, object: String) {
 882                 self.clonable_types.borrow_mut().insert(object);
 883         }
 884         pub fn is_clonable(&self, object: &str) -> bool {
 885                 self.clonable_types.borrow().contains(object)
 886         }
 887         pub fn write_new_template(&self, mangled_container: String, has_destructor: bool, created_container: &[u8]) {
 888                 self.template_file.borrow_mut().write(created_container).unwrap();
 889                 self.templates_defined.borrow_mut().insert(mangled_container, has_destructor);
 890         }
 891 }
 892
 893 /// A struct which tracks resolving rust types into C-mapped equivalents, exists for one specific
 894 /// module but contains a reference to the overall CrateTypes tracking.
 895 pub struct TypeResolver<'mod_lifetime, 'crate_lft: 'mod_lifetime> {
 896         pub module_path: &'mod_lifetime str,
 897         pub crate_types: &'mod_lifetime CrateTypes<'crate_lft>,
 898         pub types: ImportResolver<'mod_lifetime, 'crate_lft>,
 899 }
 900
 901 /// Returned by write_empty_rust_val_check_suffix to indicate what type of dereferencing needs to
 902 /// happen to get the inner value of a generic.
 903 enum EmptyValExpectedTy {
 904         /// A type which has a flag for being empty (eg an array where we treat all-0s as empty).
 905         NonPointer,
 906         /// A Option mapped as a COption_*Z
 907         OptionType,
 908         /// A pointer which we want to convert to a reference.
 909         ReferenceAsPointer,
 910 }
 911
 912 #[derive(PartialEq)]
 913 /// Describes the appropriate place to print a general type-conversion string when converting a
 914 /// container.
 915 enum ContainerPrefixLocation {
 916         /// Prints a general type-conversion string prefix and suffix outside of the
 917         /// container-conversion strings.
 918         OutsideConv,
 919         /// Prints a general type-conversion string prefix and suffix inside of the
 920         /// container-conversion strings.
 921         PerConv,
 922         /// Does not print the usual type-conversion string prefix and suffix.
 923         NoPrefix,
 924 }
 925
 926 impl<'a, 'c: 'a> TypeResolver<'a, 'c> {
 927         pub fn new(module_path: &'a str, types: ImportResolver<'a, 'c>, crate_types: &'a CrateTypes<'c>) -> Self {
 928                 Self { module_path, types, crate_types }
 929         }
 930
 931         // *************************************************
 932         // *** Well know type and conversion definitions ***
 933         // *************************************************
 934
 935         /// Returns true we if can just skip passing this to C entirely
 936         pub fn skip_path(&self, full_path: &str) -> bool {
 937                 full_path == "bitcoin::secp256k1::Secp256k1" ||
 938                 full_path == "bitcoin::secp256k1::Signing" ||
 939                 full_path == "bitcoin::secp256k1::Verification"
 940         }
 941         /// Returns true we if can just skip passing this to C entirely
 942         fn no_arg_path_to_rust(&self, full_path: &str) -> &str {
 943                 if full_path == "bitcoin::secp256k1::Secp256k1" {
 944                         "secp256k1::global::SECP256K1"
 945                 } else { unimplemented!(); }
 946         }
 947
 948         /// Returns true if the object is a primitive and is mapped as-is with no conversion
 949         /// whatsoever.
 950         pub fn is_primitive(&self, full_path: &str) -> bool {
 951                 match full_path {
 952                         "bool" => true,
 953                         "i64" => true,
 954                         "f64" => true,
 955                         "u64" => true,
 956                         "u32" => true,
 957                         "u16" => true,
 958                         "u8" => true,
 959                         "usize" => true,
 960                         _ => false,
 961                 }
 962         }
 963         pub fn is_clonable(&self, ty: &str) -> bool {
 964                 if self.crate_types.is_clonable(ty) { return true; }
 965                 if self.is_primitive(ty) { return true; }
 966                 match ty {
 967                         "()" => true,
 968                         _ => false,
 969                 }
 970         }
 971         /// Gets the C-mapped type for types which are outside of the crate, or which are manually
 972         /// ignored by for some reason need mapping anyway.
 973         fn c_type_from_path<'b>(&self, full_path: &'b str, is_ref: bool, _ptr_for_ref: bool) -> Option<&'b str> {
 974                 if self.is_primitive(full_path) {
 975                         return Some(full_path);
 976                 }
 977                 match full_path {
 978                         // Note that no !is_ref types can map to an array because Rust and C's call semantics
 979                         // for arrays are different (https://github.com/eqrion/cbindgen/issues/528)
 980
 981                         "[u8; 32]" if !is_ref => Some("crate::c_types::ThirtyTwoBytes"),
 982                         "[u8; 20]" if !is_ref => Some("crate::c_types::TwentyBytes"),
 983                         "[u8; 16]" if !is_ref => Some("crate::c_types::SixteenBytes"),
 984                         "[u8; 12]" if !is_ref => Some("crate::c_types::TwelveBytes"),
 985                         "[u8; 4]" if !is_ref => Some("crate::c_types::FourBytes"),
 986                         "[u8; 3]" if !is_ref => Some("crate::c_types::ThreeBytes"), // Used for RGB values
 987                         "[u16; 8]" if !is_ref => Some("crate::c_types::EightU16s"),
 988
 989                         "str" if is_ref => Some("crate::c_types::Str"),
 990                         "alloc::string::String"|"String" => Some("crate::c_types::Str"),
 991
 992                         "bitcoin::Address" => Some("crate::c_types::Str"),
 993
 994                         "std::time::Duration"|"core::time::Duration" => Some("u64"),
 995                         "std::time::SystemTime" => Some("u64"),
 996                         "std::io::Error"|"lightning::io::Error"|"lightning::io::ErrorKind" => Some("crate::c_types::IOError"),
 997                         "core::fmt::Arguments" if is_ref => Some("crate::c_types::Str"),
 998
 999                         "core::convert::Infallible" => Some("crate::c_types::NotConstructable"),
1000
1001                         "bitcoin::bech32::Error"|"bech32::Error"
1002                                 if !is_ref => Some("crate::c_types::Bech32Error"),
1003                         "bitcoin::secp256k1::Error"|"secp256k1::Error"
1004                                 if !is_ref => Some("crate::c_types::Secp256k1Error"),
1005
1006                         "core::num::ParseIntError" => Some("crate::c_types::Error"),
1007                         "core::str::Utf8Error" => Some("crate::c_types::Error"),
1008
1009                         "bitcoin::bech32::u5"|"bech32::u5" => Some("crate::c_types::U5"),
1010                         "u128" => Some("crate::c_types::U128"),
1011                         "core::num::NonZeroU8" => Some("u8"),
1012
1013                         "secp256k1::PublicKey"|"bitcoin::secp256k1::PublicKey" => Some("crate::c_types::PublicKey"),
1014                         "bitcoin::secp256k1::ecdsa::Signature" => Some("crate::c_types::Signature"),
1015                         "bitcoin::secp256k1::ecdsa::RecoverableSignature" => Some("crate::c_types::RecoverableSignature"),
1016                         "bitcoin::secp256k1::SecretKey" if is_ref  => Some("*const [u8; 32]"),
1017                         "bitcoin::secp256k1::SecretKey" if !is_ref => Some("crate::c_types::SecretKey"),
1018                         "bitcoin::secp256k1::KeyPair" if !is_ref => Some("crate::c_types::SecretKey"),
1019                         "bitcoin::secp256k1::Scalar" if is_ref  => Some("*const crate::c_types::BigEndianScalar"),
1020                         "bitcoin::secp256k1::Scalar" if !is_ref => Some("crate::c_types::BigEndianScalar"),
1021                         "bitcoin::secp256k1::ecdh::SharedSecret" if !is_ref => Some("crate::c_types::ThirtyTwoBytes"),
1022
1023                         "bitcoin::blockdata::script::Script"|"bitcoin::Script" if is_ref => Some("crate::c_types::u8slice"),
1024                         "bitcoin::blockdata::script::Script"|"bitcoin::Script" if !is_ref => Some("crate::c_types::derived::CVec_u8Z"),
1025                         "bitcoin::OutPoint"|"bitcoin::blockdata::transaction::OutPoint" => Some("crate::lightning::chain::transaction::OutPoint"),
1026                         "bitcoin::blockdata::transaction::Transaction"|"bitcoin::Transaction" => Some("crate::c_types::Transaction"),
1027                         "bitcoin::Witness" => Some("crate::c_types::Witness"),
1028                         "bitcoin::TxIn"|"bitcoin::blockdata::transaction::TxIn" if !is_ref => Some("crate::c_types::TxIn"),
1029                         "bitcoin::TxOut"|"bitcoin::blockdata::transaction::TxOut" => Some("crate::c_types::TxOut"),
1030                         "bitcoin::network::constants::Network" => Some("crate::bitcoin::network::Network"),
1031                         "bitcoin::util::address::WitnessVersion" => Some("crate::c_types::WitnessVersion"),
1032                         "bitcoin::blockdata::block::BlockHeader" if is_ref  => Some("*const [u8; 80]"),
1033                         "bitcoin::blockdata::block::Block" if is_ref  => Some("crate::c_types::u8slice"),
1034
1035                         "bitcoin::PackedLockTime"|"bitcoin::blockdata::locktime::PackedLockTime" => Some("u32"),
1036
1037                         "bitcoin::psbt::PartiallySignedTransaction" if !is_ref => Some("crate::c_types::derived::CVec_u8Z"),
1038
1039                         "bitcoin::PubkeyHash"|"bitcoin::hash_types::PubkeyHash"|
1040                         "bitcoin::hash_types::WPubkeyHash"|
1041                         "bitcoin::ScriptHash"|"bitcoin::hash_types::ScriptHash"
1042                                 if !is_ref => Some("crate::c_types::TwentyBytes"),
1043                         "bitcoin::PubkeyHash"|"bitcoin::hash_types::PubkeyHash"|
1044                         "bitcoin::hash_types::WPubkeyHash"|
1045                         "bitcoin::ScriptHash"|"bitcoin::hash_types::ScriptHash"
1046                                 if is_ref => Some("*const [u8; 20]"),
1047                         "bitcoin::hash_types::WScriptHash"
1048                                 if is_ref => Some("*const [u8; 32]"),
1049
1050                         // Newtypes that we just expose in their original form.
1051                         "bitcoin::hash_types::Txid"|"bitcoin::BlockHash"|"bitcoin::hash_types::BlockHash"|"bitcoin_hashes::sha256::Hash"|"bitcoin::blockdata::constants::ChainHash"
1052                                 if is_ref  => Some("*const [u8; 32]"),
1053                         "bitcoin::hash_types::Txid"|"bitcoin::BlockHash"|"bitcoin::hash_types::BlockHash"|"bitcoin_hashes::sha256::Hash"|"bitcoin::blockdata::constants::ChainHash"
1054                                 if !is_ref => Some("crate::c_types::ThirtyTwoBytes"),
1055                         "bitcoin::secp256k1::Message" if !is_ref => Some("crate::c_types::ThirtyTwoBytes"),
1056                         "lightning::ln::PaymentHash"|"lightning::ln::PaymentPreimage"|"lightning::ln::PaymentSecret"
1057                         |"lightning::ln::channelmanager::PaymentId"|"lightning::ln::channelmanager::InterceptId"
1058                         |"lightning::sign::KeyMaterial"|"lightning::chain::ClaimId"
1059                                 if is_ref => Some("*const [u8; 32]"),
1060                         "lightning::ln::PaymentHash"|"lightning::ln::PaymentPreimage"|"lightning::ln::PaymentSecret"
1061                         |"lightning::ln::channelmanager::PaymentId"|"lightning::ln::channelmanager::InterceptId"
1062                         |"lightning::sign::KeyMaterial"|"lightning::chain::ClaimId"
1063                                 if !is_ref => Some("crate::c_types::ThirtyTwoBytes"),
1064
1065                         "lightning::io::Read" => Some("crate::c_types::u8slice"),
1066
1067                         _ => None,
1068                 }
1069         }
1070
1071         fn from_c_conversion_new_var_from_path<'b>(&self, _full_path: &str, _is_ref: bool) -> Option<(&'b str, &'b str)> {
1072                 None
1073         }
1074         fn from_c_conversion_prefix_from_path<'b>(&self, full_path: &str, is_ref: bool) -> Option<String> {
1075                 if self.is_primitive(full_path) {
1076                         return Some("".to_owned());
1077                 }
1078                 match full_path {
1079                         "Vec" if !is_ref => Some("local_"),
1080                         "Result" if !is_ref => Some("local_"),
1081                         "Option" if is_ref => Some("&local_"),
1082                         "Option" => Some("local_"),
1083
1084                         "[u8; 32]" if is_ref => Some("unsafe { &*"),
1085                         "[u8; 32]" if !is_ref => Some(""),
1086                         "[u8; 20]" if !is_ref => Some(""),
1087                         "[u8; 16]" if !is_ref => Some(""),
1088                         "[u8; 12]" if !is_ref => Some(""),
1089                         "[u8; 4]" if !is_ref => Some(""),
1090                         "[u8; 3]" if !is_ref => Some(""),
1091                         "[u16; 8]" if !is_ref => Some(""),
1092
1093                         "[u8]" if is_ref => Some(""),
1094                         "[usize]" if is_ref => Some(""),
1095
1096                         "str" if is_ref => Some(""),
1097                         "alloc::string::String"|"String" => Some(""),
1098                         "std::io::Error"|"lightning::io::Error"|"lightning::io::ErrorKind" => Some(""),
1099                         // Note that we'll panic for String if is_ref, as we only have non-owned memory, we
1100                         // cannot create a &String.
1101
1102                         "core::convert::Infallible" => Some("panic!(\"You must never construct a NotConstructable! : "),
1103
1104                         "bitcoin::bech32::Error"|"bech32::Error" if !is_ref => Some(""),
1105                         "bitcoin::secp256k1::Error"|"secp256k1::Error" if !is_ref => Some(""),
1106
1107                         "core::num::ParseIntError" => Some("u8::from_str_radix(\" a\", 10).unwrap_err() /*"),
1108                         "core::str::Utf8Error" => Some("core::str::from_utf8(&[0xff]).unwrap_err() /*"),
1109
1110                         "std::time::Duration"|"core::time::Duration" => Some("core::time::Duration::from_secs("),
1111                         "std::time::SystemTime" => Some("(::std::time::SystemTime::UNIX_EPOCH + std::time::Duration::from_secs("),
1112
1113                         "bitcoin::bech32::u5"|"bech32::u5" => Some(""),
1114                         "u128" => Some(""),
1115                         "core::num::NonZeroU8" => Some("core::num::NonZeroU8::new("),
1116
1117                         "bitcoin::secp256k1::PublicKey"|"secp256k1::PublicKey" if is_ref => Some("&"),
1118                         "bitcoin::secp256k1::PublicKey"|"secp256k1::PublicKey" => Some(""),
1119                         "bitcoin::secp256k1::ecdsa::Signature" if is_ref => Some("&"),
1120                         "bitcoin::secp256k1::ecdsa::Signature" => Some(""),
1121                         "bitcoin::secp256k1::ecdsa::RecoverableSignature" => Some(""),
1122                         "bitcoin::secp256k1::SecretKey" if is_ref => Some("&::bitcoin::secp256k1::SecretKey::from_slice(&unsafe { *"),
1123                         "bitcoin::secp256k1::SecretKey" if !is_ref => Some(""),
1124                         "bitcoin::secp256k1::KeyPair" if !is_ref => Some("::bitcoin::secp256k1::KeyPair::new("),
1125                         "bitcoin::secp256k1::Scalar" if is_ref => Some("&"),
1126                         "bitcoin::secp256k1::Scalar" if !is_ref => Some(""),
1127                         "bitcoin::secp256k1::ecdh::SharedSecret" if !is_ref => Some("::bitcoin::secp256k1::ecdh::SharedSecret::from_bytes("),
1128
1129                         "bitcoin::blockdata::script::Script"|"bitcoin::Script" if is_ref => Some("&::bitcoin::blockdata::script::Script::from(Vec::from("),
1130                         "bitcoin::blockdata::script::Script"|"bitcoin::Script" if !is_ref => Some("::bitcoin::blockdata::script::Script::from("),
1131                         "bitcoin::blockdata::transaction::Transaction"|"bitcoin::Transaction" if is_ref => Some("&"),
1132                         "bitcoin::blockdata::transaction::Transaction"|"bitcoin::Transaction" => Some(""),
1133                         "bitcoin::Witness" if is_ref => Some("&"),
1134                         "bitcoin::Witness" => Some(""),
1135                         "bitcoin::OutPoint"|"bitcoin::blockdata::transaction::OutPoint" => Some("crate::c_types::C_to_bitcoin_outpoint("),
1136                         "bitcoin::TxIn"|"bitcoin::blockdata::transaction::TxIn" if !is_ref => Some(""),
1137                         "bitcoin::TxOut"|"bitcoin::blockdata::transaction::TxOut" if !is_ref => Some(""),
1138                         "bitcoin::network::constants::Network" => Some(""),
1139                         "bitcoin::util::address::WitnessVersion" => Some(""),
1140                         "bitcoin::blockdata::block::BlockHeader" => Some("&::bitcoin::consensus::encode::deserialize(unsafe { &*"),
1141                         "bitcoin::blockdata::block::Block" if is_ref => Some("&::bitcoin::consensus::encode::deserialize("),
1142
1143                         "bitcoin::PackedLockTime"|"bitcoin::blockdata::locktime::PackedLockTime" => Some("::bitcoin::PackedLockTime("),
1144
1145                         "bitcoin::psbt::PartiallySignedTransaction" if !is_ref => Some("::bitcoin::consensus::encode::deserialize("),
1146
1147                         "bitcoin::PubkeyHash"|"bitcoin::hash_types::PubkeyHash" if !is_ref =>
1148                                 Some("bitcoin::hash_types::PubkeyHash::from_hash(bitcoin::hashes::Hash::from_inner("),
1149                         "bitcoin::PubkeyHash"|"bitcoin::hash_types::PubkeyHash" if is_ref =>
1150                                 Some("&bitcoin::hash_types::PubkeyHash::from_hash(bitcoin::hashes::Hash::from_inner(unsafe { *"),
1151                         "bitcoin::hash_types::WPubkeyHash" if is_ref =>
1152                                 Some("&bitcoin::hash_types::WPubkeyHash::from_hash(bitcoin::hashes::Hash::from_inner(unsafe { *"),
1153                         "bitcoin::ScriptHash"|"bitcoin::hash_types::ScriptHash" if !is_ref =>
1154                                 Some("bitcoin::hash_types::ScriptHash::from_hash(bitcoin::hashes::Hash::from_inner("),
1155                         "bitcoin::ScriptHash"|"bitcoin::hash_types::ScriptHash" if is_ref =>
1156                                 Some("&bitcoin::hash_types::ScriptHash::from_hash(bitcoin::hashes::Hash::from_inner(unsafe { *"),
1157                         "bitcoin::hash_types::WScriptHash" if is_ref =>
1158                                 Some("&bitcoin::hash_types::WScriptHash::from_hash(bitcoin::hashes::Hash::from_inner(unsafe { *"),
1159
1160                         // Newtypes that we just expose in their original form.
1161                         "bitcoin::hash_types::Txid" if is_ref => Some("&::bitcoin::hash_types::Txid::from_slice(&unsafe { &*"),
1162                         "bitcoin::hash_types::Txid" if !is_ref => Some("::bitcoin::hash_types::Txid::from_slice(&"),
1163                         "bitcoin::hash_types::BlockHash"|"bitcoin::BlockHash" => Some("::bitcoin::hash_types::BlockHash::from_slice(&"),
1164                         "bitcoin::blockdata::constants::ChainHash" => Some("::bitcoin::blockdata::constants::ChainHash::from(&"),
1165                         "lightning::ln::PaymentHash" if !is_ref => Some("::lightning::ln::PaymentHash("),
1166                         "lightning::ln::PaymentHash" if is_ref => Some("&::lightning::ln::PaymentHash(unsafe { *"),
1167                         "lightning::ln::PaymentPreimage" if !is_ref => Some("::lightning::ln::PaymentPreimage("),
1168                         "lightning::ln::PaymentPreimage" if is_ref => Some("&::lightning::ln::PaymentPreimage(unsafe { *"),
1169                         "lightning::ln::PaymentSecret" if !is_ref => Some("::lightning::ln::PaymentSecret("),
1170                         "lightning::ln::channelmanager::PaymentId" if !is_ref => Some("::lightning::ln::channelmanager::PaymentId("),
1171                         "lightning::ln::channelmanager::PaymentId" if is_ref=> Some("&::lightning::ln::channelmanager::PaymentId( unsafe { *"),
1172                         "lightning::ln::channelmanager::InterceptId" if !is_ref => Some("::lightning::ln::channelmanager::InterceptId("),
1173                         "lightning::ln::channelmanager::InterceptId" if is_ref=> Some("&::lightning::ln::channelmanager::InterceptId( unsafe { *"),
1174                         "lightning::sign::KeyMaterial" if !is_ref => Some("::lightning::sign::KeyMaterial("),
1175                         "lightning::sign::KeyMaterial" if is_ref=> Some("&::lightning::sign::KeyMaterial( unsafe { *"),
1176                         "lightning::chain::ClaimId" if !is_ref => Some("::lightning::chain::ClaimId("),
1177                         "lightning::chain::ClaimId" if is_ref=> Some("&::lightning::chain::ClaimId( unsafe { *"),
1178
1179                         // List of traits we map (possibly during processing of other files):
1180                         "lightning::io::Read" => Some("&mut "),
1181
1182                         _ => None,
1183                 }.map(|s| s.to_owned())
1184         }
1185         fn from_c_conversion_suffix_from_path<'b>(&self, full_path: &str, is_ref: bool) -> Option<String> {
1186                 if self.is_primitive(full_path) {
1187                         return Some("".to_owned());
1188                 }
1189                 match full_path {
1190                         "Vec" if !is_ref => Some(""),
1191                         "Option" => Some(""),
1192                         "Result" if !is_ref => Some(""),
1193
1194                         "[u8; 32]" if is_ref => Some("}"),
1195                         "[u8; 32]" if !is_ref => Some(".data"),
1196                         "[u8; 20]" if !is_ref => Some(".data"),
1197                         "[u8; 16]" if !is_ref => Some(".data"),
1198                         "[u8; 12]" if !is_ref => Some(".data"),
1199                         "[u8; 4]" if !is_ref => Some(".data"),
1200                         "[u8; 3]" if !is_ref => Some(".data"),
1201                         "[u16; 8]" if !is_ref => Some(".data"),
1202
1203                         "[u8]" if is_ref => Some(".to_slice()"),
1204                         "[usize]" if is_ref => Some(".to_slice()"),
1205
1206                         "str" if is_ref => Some(".into_str()"),
1207                         "alloc::string::String"|"String" => Some(".into_string()"),
1208                         "std::io::Error"|"lightning::io::Error" => Some(".to_rust()"),
1209                         "lightning::io::ErrorKind" => Some(".to_rust_kind()"),
1210
1211                         "core::convert::Infallible" => Some("\")"),
1212
1213                         "bitcoin::bech32::Error"|"bech32::Error" if !is_ref => Some(".into_rust()"),
1214                         "bitcoin::secp256k1::Error"|"secp256k1::Error" if !is_ref => Some(".into_rust()"),
1215
1216                         "core::num::ParseIntError" => Some("*/"),
1217                         "core::str::Utf8Error" => Some("*/"),
1218
1219                         "std::time::Duration"|"core::time::Duration" => Some(")"),
1220                         "std::time::SystemTime" => Some("))"),
1221
1222                         "bitcoin::bech32::u5"|"bech32::u5" => Some(".into()"),
1223                         "u128" => Some(".into()"),
1224                         "core::num::NonZeroU8" => Some(").expect(\"Value must be non-zero\")"),
1225
1226                         "bitcoin::secp256k1::PublicKey"|"secp256k1::PublicKey" => Some(".into_rust()"),
1227                         "bitcoin::secp256k1::ecdsa::Signature" => Some(".into_rust()"),
1228                         "bitcoin::secp256k1::ecdsa::RecoverableSignature" => Some(".into_rust()"),
1229                         "bitcoin::secp256k1::SecretKey" if !is_ref => Some(".into_rust()"),
1230                         "bitcoin::secp256k1::SecretKey" if is_ref => Some("}[..]).unwrap()"),
1231                         "bitcoin::secp256k1::KeyPair" if !is_ref => Some(".into_rust())"),
1232                         "bitcoin::secp256k1::Scalar" => Some(".into_rust()"),
1233                         "bitcoin::secp256k1::ecdh::SharedSecret" if !is_ref => Some(".data)"),
1234
1235                         "bitcoin::blockdata::script::Script"|"bitcoin::Script" if is_ref => Some(".to_slice()))"),
1236                         "bitcoin::blockdata::script::Script"|"bitcoin::Script" if !is_ref => Some(".into_rust())"),
1237                         "bitcoin::blockdata::transaction::Transaction"|"bitcoin::Transaction" => Some(".into_bitcoin()"),
1238                         "bitcoin::Witness" => Some(".into_bitcoin()"),
1239                         "bitcoin::OutPoint"|"bitcoin::blockdata::transaction::OutPoint" => Some(")"),
1240                         "bitcoin::TxIn"|"bitcoin::blockdata::transaction::TxIn" if !is_ref => Some(".into_rust()"),
1241                         "bitcoin::TxOut"|"bitcoin::blockdata::transaction::TxOut" if !is_ref => Some(".into_rust()"),
1242                         "bitcoin::network::constants::Network" => Some(".into_bitcoin()"),
1243                         "bitcoin::util::address::WitnessVersion" => Some(".into()"),
1244                         "bitcoin::blockdata::block::BlockHeader" => Some(" }).unwrap()"),
1245                         "bitcoin::blockdata::block::Block" => Some(".to_slice()).unwrap()"),
1246
1247                         "bitcoin::PackedLockTime"|"bitcoin::blockdata::locktime::PackedLockTime" => Some(")"),
1248
1249                         "bitcoin::psbt::PartiallySignedTransaction" if !is_ref => Some(".as_slice()).expect(\"Invalid PSBT format\")"),
1250
1251                         "bitcoin::PubkeyHash"|"bitcoin::hash_types::PubkeyHash"|
1252                         "bitcoin::hash_types::WPubkeyHash"|"bitcoin::hash_types::WScriptHash"|
1253                         "bitcoin::ScriptHash"|"bitcoin::hash_types::ScriptHash"
1254                                 if !is_ref => Some(".data))"),
1255                         "bitcoin::PubkeyHash"|"bitcoin::hash_types::PubkeyHash"|
1256                         "bitcoin::hash_types::WPubkeyHash"|"bitcoin::hash_types::WScriptHash"|
1257                         "bitcoin::ScriptHash"|"bitcoin::hash_types::ScriptHash"
1258                                 if is_ref => Some(" }.clone()))"),
1259
1260                         // Newtypes that we just expose in their original form.
1261                         "bitcoin::hash_types::Txid" if is_ref => Some(" }[..]).unwrap()"),
1262                         "bitcoin::hash_types::Txid" => Some(".data[..]).unwrap()"),
1263                         "bitcoin::hash_types::BlockHash"|"bitcoin::BlockHash" if !is_ref => Some(".data[..]).unwrap()"),
1264                         "bitcoin::blockdata::constants::ChainHash" if !is_ref => Some(".data[..])"),
1265                         "lightning::ln::PaymentHash"|"lightning::ln::PaymentPreimage"|"lightning::ln::PaymentSecret"
1266                         |"lightning::ln::channelmanager::PaymentId"|"lightning::ln::channelmanager::InterceptId"
1267                         |"lightning::sign::KeyMaterial"|"lightning::chain::ClaimId"
1268                                 if !is_ref => Some(".data)"),
1269                         "lightning::ln::PaymentHash"|"lightning::ln::PaymentPreimage"|"lightning::ln::PaymentSecret"
1270                         |"lightning::ln::channelmanager::PaymentId"|"lightning::ln::channelmanager::InterceptId"
1271                         |"lightning::sign::KeyMaterial"|"lightning::chain::ClaimId"
1272                                 if is_ref => Some(" })"),
1273
1274                         // List of traits we map (possibly during processing of other files):
1275                         "lightning::io::Read" => Some(".to_reader()"),
1276
1277                         _ => None,
1278                 }.map(|s| s.to_owned())
1279         }
1280
1281         fn to_c_conversion_new_var_from_path<'b>(&self, full_path: &str, is_ref: bool) -> Option<(&'b str, &'b str)> {
1282                 if self.is_primitive(full_path) {
1283                         return None;
1284                 }
1285                 match full_path {
1286                         "[u8]" if is_ref => Some(("crate::c_types::u8slice::from_slice(", ")")),
1287                         "[usize]" if is_ref => Some(("crate::c_types::usizeslice::from_slice(", ")")),
1288
1289                         "bitcoin::blockdata::block::BlockHeader" if is_ref => Some(("{ let mut s = [0u8; 80]; s[..].copy_from_slice(&::bitcoin::consensus::encode::serialize(", ")); s }")),
1290                         "bitcoin::blockdata::block::Block" if is_ref => Some(("::bitcoin::consensus::encode::serialize(", ")")),
1291                         "bitcoin::hash_types::Txid" => None,
1292
1293                         _ => None,
1294                 }.map(|s| s.to_owned())
1295         }
1296         fn to_c_conversion_inline_prefix_from_path(&self, full_path: &str, is_ref: bool, _ptr_for_ref: bool) -> Option<String> {
1297                 if self.is_primitive(full_path) {
1298                         return Some("".to_owned());
1299                 }
1300                 match full_path {
1301                         "Result" if !is_ref => Some("local_"),
1302                         "Vec" if !is_ref => Some("local_"),
1303                         "Option" => Some("local_"),
1304
1305                         "[u8; 32]" if !is_ref => Some("crate::c_types::ThirtyTwoBytes { data: "),
1306                         "[u8; 32]" if is_ref => Some(""),
1307                         "[u8; 20]" if !is_ref => Some("crate::c_types::TwentyBytes { data: "),
1308                         "[u8; 16]" if !is_ref => Some("crate::c_types::SixteenBytes { data: "),
1309                         "[u8; 12]" if !is_ref => Some("crate::c_types::TwelveBytes { data: "),
1310                         "[u8; 4]" if !is_ref => Some("crate::c_types::FourBytes { data: "),
1311                         "[u8; 3]" if is_ref => Some(""),
1312                         "[u16; 8]" if !is_ref => Some("crate::c_types::EightU16s { data: "),
1313
1314                         "[u8]" if is_ref => Some("local_"),
1315                         "[usize]" if is_ref => Some("local_"),
1316
1317                         "str" if is_ref => Some(""),
1318                         "alloc::string::String"|"String" => Some(""),
1319
1320                         "bitcoin::Address" => Some("alloc::string::ToString::to_string(&"),
1321
1322                         "std::time::Duration"|"core::time::Duration" => Some(""),
1323                         "std::time::SystemTime" => Some(""),
1324                         "std::io::Error"|"lightning::io::Error" => Some("crate::c_types::IOError::from_rust("),
1325                         "lightning::io::ErrorKind" => Some("crate::c_types::IOError::from_rust_kind("),
1326                         "core::fmt::Arguments" => Some("alloc::format!(\"{}\", "),
1327
1328                         "core::convert::Infallible" => Some("panic!(\"Cannot construct an Infallible: "),
1329
1330                         "bitcoin::bech32::Error"|"bech32::Error"
1331                                 if !is_ref => Some("crate::c_types::Bech32Error::from_rust("),
1332                         "bitcoin::secp256k1::Error"|"secp256k1::Error"
1333                                 if !is_ref => Some("crate::c_types::Secp256k1Error::from_rust("),
1334
1335                         "core::num::ParseIntError" => Some("crate::c_types::Error { _dummy: 0 } /*"),
1336                         "core::str::Utf8Error" => Some("crate::c_types::Error { _dummy: 0 } /*"),
1337
1338                         "bitcoin::bech32::u5"|"bech32::u5" => Some(""),
1339                         "u128" => Some(""),
1340
1341                         "bitcoin::secp256k1::PublicKey"|"secp256k1::PublicKey" => Some("crate::c_types::PublicKey::from_rust(&"),
1342                         "bitcoin::secp256k1::ecdsa::Signature" => Some("crate::c_types::Signature::from_rust(&"),
1343                         "bitcoin::secp256k1::ecdsa::RecoverableSignature" => Some("crate::c_types::RecoverableSignature::from_rust(&"),
1344                         "bitcoin::secp256k1::SecretKey" if is_ref => Some(""),
1345                         "bitcoin::secp256k1::SecretKey" if !is_ref => Some("crate::c_types::SecretKey::from_rust("),
1346                         "bitcoin::secp256k1::KeyPair" if !is_ref => Some("crate::c_types::SecretKey::from_rust("),
1347                         "bitcoin::secp256k1::Scalar" if !is_ref => Some("crate::c_types::BigEndianScalar::from_rust(&"),
1348                         "bitcoin::secp256k1::ecdh::SharedSecret" if !is_ref => Some("crate::c_types::ThirtyTwoBytes { data: "),
1349
1350                         "bitcoin::blockdata::script::Script"|"bitcoin::Script" if is_ref => Some("crate::c_types::u8slice::from_slice(&"),
1351                         "bitcoin::blockdata::script::Script"|"bitcoin::Script" if !is_ref => Some(""),
1352                         "bitcoin::blockdata::transaction::Transaction"|"bitcoin::Transaction" if is_ref => Some("crate::c_types::Transaction::from_bitcoin("),
1353                         "bitcoin::blockdata::transaction::Transaction"|"bitcoin::Transaction" => Some("crate::c_types::Transaction::from_bitcoin(&"),
1354                         "bitcoin::Witness" if is_ref => Some("crate::c_types::Witness::from_bitcoin("),
1355                         "bitcoin::Witness" if !is_ref => Some("crate::c_types::Witness::from_bitcoin(&"),
1356                         "bitcoin::OutPoint"|"bitcoin::blockdata::transaction::OutPoint" if is_ref => Some("crate::c_types::bitcoin_to_C_outpoint("),
1357                         "bitcoin::OutPoint"|"bitcoin::blockdata::transaction::OutPoint" if !is_ref => Some("crate::c_types::bitcoin_to_C_outpoint(&"),
1358                         "bitcoin::TxIn"|"bitcoin::blockdata::transaction::TxIn" if !is_ref => Some("crate::c_types::TxIn::from_rust(&"),
1359                         "bitcoin::TxOut"|"bitcoin::blockdata::transaction::TxOut" if !is_ref => Some("crate::c_types::TxOut::from_rust(&"),
1360                         "bitcoin::TxOut"|"bitcoin::blockdata::transaction::TxOut" if is_ref => Some("crate::c_types::TxOut::from_rust("),
1361                         "bitcoin::network::constants::Network" => Some("crate::bitcoin::network::Network::from_bitcoin("),
1362                         "bitcoin::util::address::WitnessVersion" => Some(""),
1363                         "bitcoin::blockdata::block::BlockHeader" if is_ref => Some("&local_"),
1364                         "bitcoin::blockdata::block::Block" if is_ref => Some("crate::c_types::u8slice::from_slice(&local_"),
1365
1366                         "bitcoin::PackedLockTime"|"bitcoin::blockdata::locktime::PackedLockTime" => Some(""),
1367
1368                         "bitcoin::psbt::PartiallySignedTransaction" if !is_ref => Some("::bitcoin::consensus::encode::serialize(&"),
1369
1370                         "bitcoin::hash_types::Txid" if !is_ref => Some("crate::c_types::ThirtyTwoBytes { data: "),
1371
1372                         "bitcoin::PubkeyHash"|"bitcoin::hash_types::PubkeyHash"|
1373                         "bitcoin::hash_types::WPubkeyHash"|"bitcoin::hash_types::WScriptHash"|
1374                         "bitcoin::ScriptHash"|"bitcoin::hash_types::ScriptHash"
1375                                 if !is_ref => Some("crate::c_types::TwentyBytes { data: "),
1376
1377                         // Newtypes that we just expose in their original form.
1378                         "bitcoin::hash_types::Txid"|"bitcoin::BlockHash"|"bitcoin::hash_types::BlockHash"|"bitcoin_hashes::sha256::Hash"|"bitcoin::blockdata::constants::ChainHash"
1379                                 if is_ref => Some(""),
1380                         "bitcoin::hash_types::Txid"|"bitcoin::BlockHash"|"bitcoin::hash_types::BlockHash"|"bitcoin_hashes::sha256::Hash"|"bitcoin::blockdata::constants::ChainHash"
1381                                 if !is_ref => Some("crate::c_types::ThirtyTwoBytes { data: "),
1382                         "bitcoin::secp256k1::Message" if !is_ref => Some("crate::c_types::ThirtyTwoBytes { data: "),
1383                         "lightning::ln::PaymentHash"|"lightning::ln::PaymentPreimage"|"lightning::ln::PaymentSecret"
1384                         |"lightning::ln::channelmanager::PaymentId"|"lightning::ln::channelmanager::InterceptId"
1385                         |"lightning::sign::KeyMaterial"|"lightning::chain::ClaimId"
1386                                 if is_ref => Some("&"),
1387                         "lightning::ln::PaymentHash"|"lightning::ln::PaymentPreimage"|"lightning::ln::PaymentSecret"
1388                         |"lightning::ln::channelmanager::PaymentId"|"lightning::ln::channelmanager::InterceptId"
1389                         |"lightning::sign::KeyMaterial"|"lightning::chain::ClaimId"
1390                                 if !is_ref => Some("crate::c_types::ThirtyTwoBytes { data: "),
1391
1392                         "lightning::io::Read" => Some("crate::c_types::u8slice::from_vec(&crate::c_types::reader_to_vec("),
1393
1394                         _ => None,
1395                 }.map(|s| s.to_owned())
1396         }
1397         fn to_c_conversion_inline_suffix_from_path(&self, full_path: &str, is_ref: bool, _ptr_for_ref: bool) -> Option<String> {
1398                 if self.is_primitive(full_path) {
1399                         return Some("".to_owned());
1400                 }
1401                 match full_path {
1402                         "Result" if !is_ref => Some(""),
1403                         "Vec" if !is_ref => Some(".into()"),
1404                         "Option" => Some(""),
1405
1406                         "[u8; 32]" if !is_ref => Some(" }"),
1407                         "[u8; 32]" if is_ref => Some(""),
1408                         "[u8; 20]" if !is_ref => Some(" }"),
1409                         "[u8; 16]" if !is_ref => Some(" }"),
1410                         "[u8; 12]" if !is_ref => Some(" }"),
1411                         "[u8; 4]" if !is_ref => Some(" }"),
1412                         "[u8; 3]" if is_ref => Some(""),
1413                         "[u16; 8]" if !is_ref => Some(" }"),
1414
1415                         "[u8]" if is_ref => Some(""),
1416                         "[usize]" if is_ref => Some(""),
1417
1418                         "str" if is_ref => Some(".into()"),
1419                         "alloc::string::String"|"String" if is_ref => Some(".as_str().into()"),
1420                         "alloc::string::String"|"String" => Some(".into()"),
1421
1422                         "bitcoin::Address" => Some(").into()"),
1423
1424                         "std::time::Duration"|"core::time::Duration" => Some(".as_secs()"),
1425                         "std::time::SystemTime" => Some(".duration_since(::std::time::SystemTime::UNIX_EPOCH).expect(\"Times must be post-1970\").as_secs()"),
1426                         "std::io::Error"|"lightning::io::Error"|"lightning::io::ErrorKind" => Some(")"),
1427                         "core::fmt::Arguments" => Some(").into()"),
1428
1429                         "core::convert::Infallible" => Some("\")"),
1430
1431                         "bitcoin::secp256k1::Error"|"bech32::Error"
1432                                 if !is_ref => Some(")"),
1433                         "bitcoin::secp256k1::Error"|"secp256k1::Error"
1434                                 if !is_ref => Some(")"),
1435
1436                         "core::num::ParseIntError" => Some("*/"),
1437                         "core::str::Utf8Error" => Some("*/"),
1438
1439                         "bitcoin::bech32::u5"|"bech32::u5" => Some(".into()"),
1440                         "u128" => Some(".into()"),
1441
1442                         "bitcoin::secp256k1::PublicKey"|"secp256k1::PublicKey" => Some(")"),
1443                         "bitcoin::secp256k1::ecdsa::Signature" => Some(")"),
1444                         "bitcoin::secp256k1::ecdsa::RecoverableSignature" => Some(")"),
1445                         "bitcoin::secp256k1::SecretKey" if !is_ref => Some(")"),
1446                         "bitcoin::secp256k1::SecretKey" if is_ref => Some(".as_ref()"),
1447                         "bitcoin::secp256k1::KeyPair" if !is_ref => Some(".secret_key())"),
1448                         "bitcoin::secp256k1::Scalar" if !is_ref => Some(")"),
1449                         "bitcoin::secp256k1::ecdh::SharedSecret" if !is_ref => Some(".secret_bytes() }"),
1450
1451                         "bitcoin::blockdata::script::Script"|"bitcoin::Script" if is_ref => Some("[..])"),
1452                         "bitcoin::blockdata::script::Script"|"bitcoin::Script" if !is_ref => Some(".into_bytes().into()"),
1453                         "bitcoin::blockdata::transaction::Transaction"|"bitcoin::Transaction" => Some(")"),
1454                         "bitcoin::Witness" => Some(")"),
1455                         "bitcoin::OutPoint"|"bitcoin::blockdata::transaction::OutPoint" => Some(")"),
1456                         "bitcoin::TxIn"|"bitcoin::blockdata::transaction::TxIn" if !is_ref => Some(")"),
1457                         "bitcoin::TxOut"|"bitcoin::blockdata::transaction::TxOut" => Some(")"),
1458                         "bitcoin::network::constants::Network" => Some(")"),
1459                         "bitcoin::util::address::WitnessVersion" => Some(".into()"),
1460                         "bitcoin::blockdata::block::BlockHeader" if is_ref => Some(""),
1461                         "bitcoin::blockdata::block::Block" if is_ref => Some(")"),
1462
1463                         "bitcoin::PackedLockTime"|"bitcoin::blockdata::locktime::PackedLockTime" => Some(".0"),
1464
1465                         "bitcoin::psbt::PartiallySignedTransaction" if !is_ref => Some(").into()"),
1466
1467                         "bitcoin::hash_types::Txid" if !is_ref => Some(".into_inner() }"),
1468
1469                         "bitcoin::PubkeyHash"|"bitcoin::hash_types::PubkeyHash"|
1470                         "bitcoin::hash_types::WPubkeyHash"|"bitcoin::hash_types::WScriptHash"|
1471                         "bitcoin::ScriptHash"|"bitcoin::hash_types::ScriptHash"
1472                                 if !is_ref => Some(".as_hash().into_inner() }"),
1473
1474                         // Newtypes that we just expose in their original form.
1475                         "bitcoin::hash_types::Txid"|"bitcoin::BlockHash"|"bitcoin::hash_types::BlockHash"|"bitcoin_hashes::sha256::Hash"
1476                                 if is_ref => Some(".as_inner()"),
1477                         "bitcoin::hash_types::Txid"|"bitcoin::BlockHash"|"bitcoin::hash_types::BlockHash"|"bitcoin_hashes::sha256::Hash"
1478                                 if !is_ref => Some(".into_inner() }"),
1479                         "bitcoin::blockdata::constants::ChainHash" if is_ref => Some(".as_bytes() }"),
1480                         "bitcoin::blockdata::constants::ChainHash" if !is_ref => Some(".to_bytes() }"),
1481                         "bitcoin::secp256k1::Message" if !is_ref => Some(".as_ref().clone() }"),
1482                         "lightning::ln::PaymentHash"|"lightning::ln::PaymentPreimage"|"lightning::ln::PaymentSecret"
1483                         |"lightning::ln::channelmanager::PaymentId"|"lightning::ln::channelmanager::InterceptId"
1484                         |"lightning::sign::KeyMaterial"|"lightning::chain::ClaimId"
1485                                 if is_ref => Some(".0"),
1486                         "lightning::ln::PaymentHash"|"lightning::ln::PaymentPreimage"|"lightning::ln::PaymentSecret"
1487                         |"lightning::ln::channelmanager::PaymentId"|"lightning::ln::channelmanager::InterceptId"
1488                         |"lightning::sign::KeyMaterial"|"lightning::chain::ClaimId"
1489                                 if !is_ref => Some(".0 }"),
1490
1491                         "lightning::io::Read" => Some("))"),
1492
1493                         _ => None,
1494                 }.map(|s| s.to_owned())
1495         }
1496
1497         fn empty_val_check_suffix_from_path(&self, full_path: &str) -> Option<&str> {
1498                 match full_path {
1499                         "secp256k1::PublicKey"|"bitcoin::secp256k1::PublicKey" => Some(".is_null()"),
1500                         "bitcoin::secp256k1::ecdsa::Signature" => Some(".is_null()"),
1501                         _ => None
1502                 }
1503         }
1504
1505         /// When printing a reference to the source crate's rust type, if we need to map it to a
1506         /// different "real" type, it can be done so here.
1507         /// This is useful to work around limitations in the binding type resolver, where we reference
1508         /// a non-public `use` alias.
1509         /// TODO: We should never need to use this!
1510         fn real_rust_type_mapping<'equiv>(&self, thing: &'equiv str) -> &'equiv str {
1511                 match thing {
1512                         "lightning::io::Read" => "crate::c_types::io::Read",
1513                         _ => thing,
1514                 }
1515         }
1516
1517         // ****************************
1518         // *** Container Processing ***
1519         // ****************************
1520
1521         /// Returns the module path in the generated mapping crate to the containers which we generate
1522         /// when writing to CrateTypes::template_file.
1523         pub fn generated_container_path() -> &'static str {
1524                 "crate::c_types::derived"
1525         }
1526         /// Returns the module path in the generated mapping crate to the container templates, which
1527         /// are then concretized and put in the generated container path/template_file.
1528         fn container_templ_path() -> &'static str {
1529                 "crate::c_types"
1530         }
1531
1532         /// This should just be a closure, but doing so gets an error like
1533         /// error: reached the recursion limit while instantiating `types::TypeResolver::is_transpar...c/types.rs:1358:104: 1358:110]>>`
1534         /// which implies the concrete function instantiation of `is_transparent_container` ends up
1535         /// being recursive.
1536         fn deref_type<'one, 'b: 'one> (obj: &'one &'b syn::Type) -> &'b syn::Type { *obj }
1537
1538         /// Returns true if the path containing the given args is a "transparent" container, ie an
1539         /// Option or a container which does not require a generated continer class.
1540         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 {
1541                 if full_path == "Option" {
1542                         let inner = args.next().unwrap();
1543                         assert!(args.next().is_none());
1544                         match generics.resolve_type(inner) {
1545                                 syn::Type::Reference(r) => {
1546                                         let elem = &*r.elem;
1547                                         match elem {
1548                                                 syn::Type::Path(_) =>
1549                                                         self.is_transparent_container(full_path, true, [elem].iter().map(Self::deref_type), generics),
1550                                                 _ => true,
1551                                         }
1552                                 },
1553                                 syn::Type::Array(a) => {
1554                                         if let syn::Expr::Lit(l) = &a.len {
1555                                                 if let syn::Lit::Int(i) = &l.lit {
1556                                                         if i.base10_digits().parse::<usize>().unwrap() >= 32 {
1557                                                                 let mut buf = Vec::new();
1558                                                                 self.write_rust_type(&mut buf, generics, &a.elem, false);
1559                                                                 let ty = String::from_utf8(buf).unwrap();
1560                                                                 ty == "u8"
1561                                                         } else {
1562                                                                 // Blindly assume that if we're trying to create an empty value for an
1563                                                                 // array < 32 entries that all-0s may be a valid state.
1564                                                                 unimplemented!();
1565                                                         }
1566                                                 } else { unimplemented!(); }
1567                                         } else { unimplemented!(); }
1568                                 },
1569                                 syn::Type::Path(p) => {
1570                                         if let Some(resolved) = self.maybe_resolve_path(&p.path, generics) {
1571                                                 if self.c_type_has_inner_from_path(&resolved) { return true; }
1572                                                 if self.is_primitive(&resolved) { return false; }
1573                                                 // We want to move to using `Option_` mappings where possible rather than
1574                                                 // manual mappings, as it makes downstream bindings simpler and is more
1575                                                 // clear for users. Thus, we default to false but override for a few
1576                                                 // types which had mappings defined when we were avoiding the `Option_`s.
1577                                                 match &resolved as &str {
1578                                                         "secp256k1::PublicKey"|"bitcoin::secp256k1::PublicKey" => true,
1579                                                         _ => false,
1580                                                 }
1581                                         } else { unimplemented!(); }
1582                                 },
1583                                 syn::Type::Tuple(_) => false,
1584                                 _ => unimplemented!(),
1585                         }
1586                 } else { false }
1587         }
1588         /// Returns true if the path is a "transparent" container, ie an Option or a container which does
1589         /// not require a generated continer class.
1590         pub fn is_path_transparent_container(&self, full_path: &syn::Path, generics: Option<&GenericTypes>, is_ref: bool) -> bool {
1591                 let inner_iter = match &full_path.segments.last().unwrap().arguments {
1592                         syn::PathArguments::None => return false,
1593                         syn::PathArguments::AngleBracketed(args) => args.args.iter().map(|arg| {
1594                                 if let syn::GenericArgument::Type(ref ty) = arg {
1595                                         ty
1596                                 } else { unimplemented!() }
1597                         }),
1598                         syn::PathArguments::Parenthesized(_) => unimplemented!(),
1599                 };
1600                 self.is_transparent_container(&self.resolve_path(full_path, generics), is_ref, inner_iter, generics)
1601         }
1602         /// Returns true if this is a known, supported, non-transparent container.
1603         fn is_known_container(&self, full_path: &str, is_ref: bool) -> bool {
1604                 (full_path == "Result" && !is_ref) || (full_path == "Vec" && !is_ref) || full_path.ends_with("Tuple") || full_path == "Option"
1605         }
1606         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)
1607                         // Returns prefix + Vec<(prefix, var-name-to-inline-convert)> + suffix
1608                         // expecting one element in the vec per generic type, each of which is inline-converted
1609                         -> Option<(&'b str, Vec<(String, String)>, &'b str, ContainerPrefixLocation)> {
1610                 match full_path {
1611                         "Result" if !is_ref => {
1612                                 Some(("match ",
1613                                                 vec![(" { Ok(mut o) => crate::c_types::CResultTempl::ok(".to_string(), "o".to_string()),
1614                                                         (").into(), Err(mut e) => crate::c_types::CResultTempl::err(".to_string(), "e".to_string())],
1615                                                 ").into() }", ContainerPrefixLocation::PerConv))
1616                         },
1617                         "Vec" => {
1618                                 if is_ref {
1619                                         // We should only get here if the single contained has an inner
1620                                         assert!(self.c_type_has_inner(single_contained.unwrap()));
1621                                 }
1622                                 Some(("Vec::new(); for mut item in ", vec![(format!(".drain(..) {{ local_{}.push(", var_name), "item".to_string())], "); }", ContainerPrefixLocation::PerConv))
1623                         },
1624                         "Slice" => {
1625                                 if let Some(syn::Type::Reference(_)) = single_contained {
1626                                         Some(("Vec::new(); for item in ", vec![(format!(".iter() {{ local_{}.push(", var_name), "(*item)".to_string())], "); }", ContainerPrefixLocation::PerConv))
1627                                 } else {
1628                                         Some(("Vec::new(); for item in ", vec![(format!(".iter() {{ local_{}.push(", var_name), "item".to_string())], "); }", ContainerPrefixLocation::PerConv))
1629                                 }
1630                         },
1631                         "Option" => {
1632                                 let mut is_contained_ref = false;
1633                                 let contained_struct = if let Some(syn::Type::Path(p)) = single_contained {
1634                                         Some(self.resolve_path(&p.path, generics))
1635                                 } else if let Some(syn::Type::Reference(r)) = single_contained {
1636                                         is_contained_ref = true;
1637                                         if let syn::Type::Path(p) = &*r.elem {
1638                                                 Some(self.resolve_path(&p.path, generics))
1639                                         } else { None }
1640                                 } else { None };
1641                                 if let Some(inner_path) = contained_struct {
1642                                         let only_contained_has_inner = self.c_type_has_inner_from_path(&inner_path);
1643                                         if self.c_type_has_inner_from_path(&inner_path) {
1644                                                 let is_inner_ref = if let Some(syn::Type::Reference(_)) = single_contained { true } else { false };
1645                                                 if is_ref {
1646                                                         return Some(("if ", vec![
1647                                                                 (".is_none() { core::ptr::null() } else { ObjOps::nonnull_ptr_to_inner(".to_owned(),
1648                                                                         format!("({}{}.unwrap())", var_access, if is_inner_ref { "" } else { ".as_ref()" }))
1649                                                                 ], ") }", ContainerPrefixLocation::OutsideConv));
1650                                                 } else {
1651                                                         return Some(("if ", vec![
1652                                                                 (".is_none() { core::ptr::null_mut() } else { ".to_owned(), format!("({}.unwrap())", var_access))
1653                                                                 ], " }", ContainerPrefixLocation::OutsideConv));
1654                                                 }
1655                                         } else if !self.is_transparent_container("Option", is_ref, [single_contained.unwrap()].iter().map(|a| *a), generics) {
1656                                                 if self.is_primitive(&inner_path) || (!is_contained_ref && !is_ref) || only_contained_has_inner {
1657                                                         let inner_name = self.get_c_mangled_container_type(vec![single_contained.unwrap()], generics, "Option").unwrap();
1658                                                         return Some(("if ", vec![
1659                                                                 (format!(".is_none() {{ {}::None }} else {{ {}::Some(", inner_name, inner_name),
1660                                                                  format!("{}.unwrap()", var_access))
1661                                                                 ], ") }", ContainerPrefixLocation::PerConv));
1662                                                 } else {
1663                                                         let inner_name = self.get_c_mangled_container_type(vec![single_contained.unwrap()], generics, "Option").unwrap();
1664                                                         return Some(("if ", vec![
1665                                                                 (format!(".is_none() {{ {}::None }} else {{ {}::Some(/* WARNING: CLONING CONVERSION HERE! &Option<Enum> is otherwise un-expressable. */", inner_name, inner_name),
1666                                                                  format!("(*{}.as_ref().unwrap()).clone()", var_access))
1667                                                                 ], ") }", ContainerPrefixLocation::PerConv));
1668                                                 }
1669                                         } else {
1670                                                 // If c_type_from_path is some (ie there's a manual mapping for the inner
1671                                                 // type), lean on write_empty_rust_val, below.
1672                                         }
1673                                 }
1674                                 if let Some(t) = single_contained {
1675                                         if let syn::Type::Tuple(syn::TypeTuple { elems, .. }) = t {
1676                                                 let inner_name = self.get_c_mangled_container_type(vec![single_contained.unwrap()], generics, "Option").unwrap();
1677                                                 if elems.is_empty() {
1678                                                         return Some(("if ", vec![
1679                                                                 (format!(".is_none() {{ {}::None }} else {{ {}::Some /* ",
1680                                                                         inner_name, inner_name), format!(""))
1681                                                                 ], " */ }", ContainerPrefixLocation::PerConv));
1682                                                 } else {
1683                                                         return Some(("if ", vec![
1684                                                                 (format!(".is_none() {{ {}::None }} else {{ {}::Some(",
1685                                                                         inner_name, inner_name), format!("({}.unwrap())", var_access))
1686                                                                 ], ") }", ContainerPrefixLocation::PerConv));
1687                                                 }
1688                                         }
1689                                         if let syn::Type::Reference(syn::TypeReference { elem, .. }) = t {
1690                                                 if let syn::Type::Slice(_) = &**elem {
1691                                                         return Some(("if ", vec![
1692                                                                         (".is_none() { SmartPtr::null() } else { SmartPtr::from_obj(".to_string(),
1693                                                                          format!("({}.unwrap())", var_access))
1694                                                                 ], ") }", ContainerPrefixLocation::PerConv));
1695                                                 }
1696                                         }
1697                                         let mut v = Vec::new();
1698                                         self.write_empty_rust_val(generics, &mut v, t);
1699                                         let s = String::from_utf8(v).unwrap();
1700                                         return Some(("if ", vec![
1701                                                 (format!(".is_none() {{ {} }} else {{ ", s), format!("({}.unwrap())", var_access))
1702                                                 ], " }", ContainerPrefixLocation::PerConv));
1703                                 } else { unreachable!(); }
1704                         },
1705                         _ => None,
1706                 }
1707         }
1708
1709         /// only_contained_has_inner implies that there is only one contained element in the container
1710         /// and it has an inner field (ie is an "opaque" type we've defined).
1711         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)
1712                         // Returns prefix + Vec<(prefix, var-name-to-inline-convert)> + suffix
1713                         // expecting one element in the vec per generic type, each of which is inline-converted
1714                         -> Option<(&'b str, Vec<(String, String)>, &'b str, ContainerPrefixLocation)> {
1715                 let mut only_contained_has_inner = false;
1716                 let only_contained_resolved = if let Some(syn::Type::Path(p)) = single_contained {
1717                         let res = self.resolve_path(&p.path, generics);
1718                         only_contained_has_inner = self.c_type_has_inner_from_path(&res);
1719                         Some(res)
1720                 } else { None };
1721                 match full_path {
1722                         "Result" if !is_ref => {
1723                                 Some(("match ",
1724                                                 vec![(".result_ok { true => Ok(".to_string(), format!("(*unsafe {{ Box::from_raw(<*mut _>::take_ptr(&mut {}.contents.result)) }})", var_access)),
1725                                                      ("), false => Err(".to_string(), format!("(*unsafe {{ Box::from_raw(<*mut _>::take_ptr(&mut {}.contents.err)) }})", var_access))],
1726                                                 ")}", ContainerPrefixLocation::PerConv))
1727                         },
1728                         "Slice" if is_ref && only_contained_has_inner => {
1729                                 Some(("Vec::new(); for mut item in ", vec![(format!(".as_slice().iter() {{ local_{}.push(", var_name), "item".to_string())], "); }", ContainerPrefixLocation::PerConv))
1730                         },
1731                         "Vec"|"Slice" => {
1732                                 Some(("Vec::new(); for mut item in ", vec![(format!(".into_rust().drain(..) {{ local_{}.push(", var_name), "item".to_string())], "); }", ContainerPrefixLocation::PerConv))
1733                         },
1734                         "Option" => {
1735                                 if let Some(resolved) = only_contained_resolved {
1736                                         if self.is_primitive(&resolved) {
1737                                                 return Some(("if ", vec![(".is_some() { Some(".to_string(), format!("{}.take()", var_access))], ") } else { None }", ContainerPrefixLocation::NoPrefix))
1738                                         } else if only_contained_has_inner {
1739                                                 if is_ref {
1740                                                         return Some(("if ", vec![(".inner.is_null() { None } else { Some((*".to_string(), format!("{}", var_access))], ").clone()) }", ContainerPrefixLocation::PerConv))
1741                                                 } else {
1742                                                         return Some(("if ", vec![(".inner.is_null() { None } else { Some(".to_string(), format!("{}", var_access))], ") }", ContainerPrefixLocation::PerConv));
1743                                                 }
1744                                         }
1745                                 }
1746
1747                                 if let Some(t) = single_contained {
1748                                         match t {
1749                                                 syn::Type::Reference(_)|syn::Type::Path(_)|syn::Type::Slice(_)|syn::Type::Array(_) => {
1750                                                         let mut v = Vec::new();
1751                                                         let ret_ref = self.write_empty_rust_val_check_suffix(generics, &mut v, t);
1752                                                         let s = String::from_utf8(v).unwrap();
1753                                                         match ret_ref {
1754                                                                 EmptyValExpectedTy::ReferenceAsPointer =>
1755                                                                         return Some(("if ", vec![
1756                                                                                 (format!("{} {{ None }} else {{ Some(", s), format!("unsafe {{ &mut *{} }}", var_access))
1757                                                                         ], ") }", ContainerPrefixLocation::NoPrefix)),
1758                                                                 EmptyValExpectedTy::OptionType =>
1759                                                                         return Some(("{ /*", vec![
1760                                                                                 (format!("*/ let {}_opt = {}; if {}_opt{} {{ None }} else {{ Some({{", var_name, var_access, var_name, s),
1761                                                                                 format!("{{ {}_opt.take() }}", var_name))
1762                                                                         ], "})} }", ContainerPrefixLocation::PerConv)),
1763                                                                 EmptyValExpectedTy::NonPointer =>
1764                                                                         return Some(("if ", vec![
1765                                                                                 (format!("{} {{ None }} else {{ Some(", s), format!("{}", var_access))
1766                                                                         ], ") }", ContainerPrefixLocation::PerConv)),
1767                                                         }
1768                                                 },
1769                                                 syn::Type::Tuple(_) => {
1770                                                         return Some(("if ", vec![(".is_some() { Some(".to_string(), format!("{}.take()", var_access))], ") } else { None }", ContainerPrefixLocation::PerConv))
1771                                                 },
1772                                                 _ => unimplemented!(),
1773                                         }
1774                                 } else { unreachable!(); }
1775                         },
1776                         _ => None,
1777                 }
1778         }
1779
1780         /// Constructs a reference to the given type, possibly tweaking the type if relevant to make it
1781         /// convertable to C.
1782         pub fn create_ownable_reference(&self, t: &syn::Type, generics: Option<&GenericTypes>) -> Option<syn::Type> {
1783                 let default_value = Some(syn::Type::Reference(syn::TypeReference {
1784                         and_token: syn::Token!(&)(Span::call_site()), lifetime: None, mutability: None,
1785                         elem: Box::new(t.clone()) }));
1786                 match generics.resolve_type(t) {
1787                         syn::Type::Path(p) => {
1788                                 if let Some(resolved_path) = self.maybe_resolve_path(&p.path, generics) {
1789                                         if resolved_path != "Vec" { return default_value; }
1790                                         if p.path.segments.len() != 1 { unimplemented!(); }
1791                                         let only_seg = p.path.segments.iter().next().unwrap();
1792                                         if let syn::PathArguments::AngleBracketed(args) = &only_seg.arguments {
1793                                                 if args.args.len() != 1 { unimplemented!(); }
1794                                                 let inner_arg = args.args.iter().next().unwrap();
1795                                                 if let syn::GenericArgument::Type(ty) = &inner_arg {
1796                                                         let mut can_create = self.c_type_has_inner(&ty);
1797                                                         if let syn::Type::Path(inner) = ty {
1798                                                                 if inner.path.segments.len() == 1 &&
1799                                                                                 format!("{}", inner.path.segments[0].ident) == "Vec" {
1800                                                                         can_create = true;
1801                                                                 }
1802                                                         }
1803                                                         if !can_create { return default_value; }
1804                                                         if let Some(inner_ty) = self.create_ownable_reference(&ty, generics) {
1805                                                                 return Some(syn::Type::Reference(syn::TypeReference {
1806                                                                         and_token: syn::Token![&](Span::call_site()),
1807                                                                         lifetime: None,
1808                                                                         mutability: None,
1809                                                                         elem: Box::new(syn::Type::Slice(syn::TypeSlice {
1810                                                                                 bracket_token: syn::token::Bracket { span: Span::call_site() },
1811                                                                                 elem: Box::new(inner_ty)
1812                                                                         }))
1813                                                                 }));
1814                                                         } else { return default_value; }
1815                                                 } else { unimplemented!(); }
1816                                         } else { unimplemented!(); }
1817                                 } else { return None; }
1818                         },
1819                         _ => default_value,
1820                 }
1821         }
1822
1823         // *************************************************
1824         // *** Type definition during main.rs processing ***
1825         // *************************************************
1826
1827         /// Returns true if the object at the given path is mapped as X { inner: *mut origX, .. }.
1828         pub fn c_type_has_inner_from_path(&self, full_path: &str) -> bool {
1829                 self.crate_types.opaques.get(full_path).is_some()
1830         }
1831
1832         /// Returns true if the object at the given path is mapped as X { inner: *mut origX, .. }.
1833         pub fn c_type_has_inner(&self, ty: &syn::Type) -> bool {
1834                 match ty {
1835                         syn::Type::Path(p) => {
1836                                 if let Some(full_path) = self.maybe_resolve_path(&p.path, None) {
1837                                         self.c_type_has_inner_from_path(&full_path)
1838                                 } else { false }
1839                         },
1840                         syn::Type::Reference(r) => {
1841                                 self.c_type_has_inner(&*r.elem)
1842                         },
1843                         _ => false,
1844                 }
1845         }
1846
1847         pub fn maybe_resolve_ident(&self, id: &syn::Ident) -> Option<String> {
1848                 self.types.maybe_resolve_ident(id)
1849         }
1850
1851         pub fn maybe_resolve_path(&self, p_arg: &syn::Path, generics: Option<&GenericTypes>) -> Option<String> {
1852                 self.types.maybe_resolve_path(p_arg, generics)
1853         }
1854         pub fn resolve_path(&self, p: &syn::Path, generics: Option<&GenericTypes>) -> String {
1855                 self.maybe_resolve_path(p, generics).unwrap()
1856         }
1857
1858         // ***********************************
1859         // *** Original Rust Type Printing ***
1860         // ***********************************
1861
1862         fn in_rust_prelude(resolved_path: &str) -> bool {
1863                 match resolved_path {
1864                         "Vec" => true,
1865                         "Result" => true,
1866                         "Option" => true,
1867                         _ => false,
1868                 }
1869         }
1870
1871         fn write_rust_path<W: std::io::Write>(&self, w: &mut W, generics_resolver: Option<&GenericTypes>, path: &syn::Path, with_ref_lifetime: bool, generated_crate_ref: bool) {
1872                 if let Some(resolved) = self.maybe_resolve_path(&path, generics_resolver) {
1873                         if self.is_primitive(&resolved) {
1874                                 write!(w, "{}", path.get_ident().unwrap()).unwrap();
1875                         } else {
1876                                 // TODO: We should have a generic "is from a dependency" check here instead of
1877                                 // checking for "bitcoin" explicitly.
1878                                 if resolved.starts_with("bitcoin::") || Self::in_rust_prelude(&resolved) {
1879                                         write!(w, "{}", resolved).unwrap();
1880                                 } else if !generated_crate_ref {
1881                                         // If we're printing a generic argument, it needs to reference the crate, otherwise
1882                                         // the original crate.
1883                                         write!(w, "{}", self.real_rust_type_mapping(&resolved)).unwrap();
1884                                 } else {
1885                                         write!(w, "crate::{}", resolved).unwrap();
1886                                 }
1887                         }
1888                         if let syn::PathArguments::AngleBracketed(args) = &path.segments.iter().last().unwrap().arguments {
1889                                 self.write_rust_generic_arg(w, generics_resolver, args.args.iter(), with_ref_lifetime);
1890                         }
1891                 } else {
1892                         if path.leading_colon.is_some() {
1893                                 write!(w, "::").unwrap();
1894                         }
1895                         for (idx, seg) in path.segments.iter().enumerate() {
1896                                 if idx != 0 { write!(w, "::").unwrap(); }
1897                                 write!(w, "{}", seg.ident).unwrap();
1898                                 if let syn::PathArguments::AngleBracketed(args) = &seg.arguments {
1899                                         self.write_rust_generic_arg(w, generics_resolver, args.args.iter(), with_ref_lifetime);
1900                                 }
1901                         }
1902                 }
1903         }
1904         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>) {
1905                 let mut had_params = false;
1906                 for (idx, arg) in generics.enumerate() {
1907                         if idx != 0 { write!(w, ", ").unwrap(); } else { write!(w, "<").unwrap(); }
1908                         had_params = true;
1909                         match arg {
1910                                 syn::GenericParam::Lifetime(lt) => write!(w, "'{}", lt.lifetime.ident).unwrap(),
1911                                 syn::GenericParam::Type(t) => {
1912                                         write!(w, "{}", t.ident).unwrap();
1913                                         if t.colon_token.is_some() { write!(w, ":").unwrap(); }
1914                                         for (idx, bound) in t.bounds.iter().enumerate() {
1915                                                 if idx != 0 { write!(w, " + ").unwrap(); }
1916                                                 match bound {
1917                                                         syn::TypeParamBound::Trait(tb) => {
1918                                                                 if tb.paren_token.is_some() || tb.lifetimes.is_some() { unimplemented!(); }
1919                                                                 self.write_rust_path(w, generics_resolver, &tb.path, false, false);
1920                                                         },
1921                                                         _ => unimplemented!(),
1922                                                 }
1923                                         }
1924                                         if t.eq_token.is_some() || t.default.is_some() { unimplemented!(); }
1925                                 },
1926                                 _ => unimplemented!(),
1927                         }
1928                 }
1929                 if had_params { write!(w, ">").unwrap(); }
1930         }
1931
1932         pub fn write_rust_generic_arg<'b, W: std::io::Write>(&self, w: &mut W, generics_resolver: Option<&GenericTypes>, generics: impl Iterator<Item=&'b syn::GenericArgument>, with_ref_lifetime: bool) {
1933                 write!(w, "<").unwrap();
1934                 for (idx, arg) in generics.enumerate() {
1935                         if idx != 0 { write!(w, ", ").unwrap(); }
1936                         match arg {
1937                                 syn::GenericArgument::Type(t) => self.write_rust_type(w, generics_resolver, t, with_ref_lifetime),
1938                                 _ => unimplemented!(),
1939                         }
1940                 }
1941                 write!(w, ">").unwrap();
1942         }
1943         fn do_write_rust_type<W: std::io::Write>(&self, w: &mut W, generics: Option<&GenericTypes>, t: &syn::Type, with_ref_lifetime: bool, force_crate_ref: bool) {
1944                 let real_ty = generics.resolve_type(t);
1945                 let mut generate_crate_ref = force_crate_ref || t != real_ty;
1946                 match real_ty {
1947                         syn::Type::Path(p) => {
1948                                 if p.qself.is_some() {
1949                                         unimplemented!();
1950                                 }
1951                                 if let Some(resolved_ty) = self.maybe_resolve_path(&p.path, generics) {
1952                                         generate_crate_ref |= self.maybe_resolve_path(&p.path, None).as_ref() != Some(&resolved_ty);
1953                                         if self.crate_types.traits.get(&resolved_ty).is_none() { generate_crate_ref = false; }
1954                                 }
1955                                 self.write_rust_path(w, generics, &p.path, with_ref_lifetime, generate_crate_ref);
1956                         },
1957                         syn::Type::Reference(r) => {
1958                                 write!(w, "&").unwrap();
1959                                 if let Some(lft) = &r.lifetime {
1960                                         write!(w, "'{} ", lft.ident).unwrap();
1961                                 } else if with_ref_lifetime {
1962                                         write!(w, "'static ").unwrap();
1963                                 }
1964                                 if r.mutability.is_some() {
1965                                         write!(w, "mut ").unwrap();
1966                                 }
1967                                 self.do_write_rust_type(w, generics, &*r.elem, with_ref_lifetime, generate_crate_ref);
1968                         },
1969                         syn::Type::Array(a) => {
1970                                 write!(w, "[").unwrap();
1971                                 self.do_write_rust_type(w, generics, &a.elem, with_ref_lifetime, generate_crate_ref);
1972                                 if let syn::Expr::Lit(l) = &a.len {
1973                                         if let syn::Lit::Int(i) = &l.lit {
1974                                                 write!(w, "; {}]", i).unwrap();
1975                                         } else { unimplemented!(); }
1976                                 } else { unimplemented!(); }
1977                         }
1978                         syn::Type::Slice(s) => {
1979                                 write!(w, "[").unwrap();
1980                                 self.do_write_rust_type(w, generics, &s.elem, with_ref_lifetime, generate_crate_ref);
1981                                 write!(w, "]").unwrap();
1982                         },
1983                         syn::Type::Tuple(s) => {
1984                                 write!(w, "(").unwrap();
1985                                 for (idx, t) in s.elems.iter().enumerate() {
1986                                         if idx != 0 { write!(w, ", ").unwrap(); }
1987                                         self.do_write_rust_type(w, generics, &t, with_ref_lifetime, generate_crate_ref);
1988                                 }
1989                                 write!(w, ")").unwrap();
1990                         },
1991                         _ => unimplemented!(),
1992                 }
1993         }
1994         pub fn write_rust_type<W: std::io::Write>(&self, w: &mut W, generics: Option<&GenericTypes>, t: &syn::Type, with_ref_lifetime: bool) {
1995                 self.do_write_rust_type(w, generics, t, with_ref_lifetime, false);
1996         }
1997
1998
1999         /// Prints a constructor for something which is "uninitialized" (but obviously not actually
2000         /// unint'd memory).
2001         pub fn write_empty_rust_val<W: std::io::Write>(&self, generics: Option<&GenericTypes>, w: &mut W, t: &syn::Type) {
2002                 match t {
2003                         syn::Type::Reference(r) => {
2004                                 self.write_empty_rust_val(generics, w, &*r.elem)
2005                         },
2006                         syn::Type::Path(p) => {
2007                                 let resolved = self.resolve_path(&p.path, generics);
2008                                 if self.crate_types.opaques.get(&resolved).is_some() {
2009                                         write!(w, "crate::{} {{ inner: core::ptr::null_mut(), is_owned: true }}", resolved).unwrap();
2010                                 } else {
2011                                         // Assume its a manually-mapped C type, where we can just define an null() fn
2012                                         write!(w, "{}::null()", self.c_type_from_path(&resolved, false, false).unwrap()).unwrap();
2013                                 }
2014                         },
2015                         syn::Type::Array(a) => {
2016                                 if let syn::Expr::Lit(l) = &a.len {
2017                                         if let syn::Lit::Int(i) = &l.lit {
2018                                                 if i.base10_digits().parse::<usize>().unwrap() < 32 {
2019                                                         // Blindly assume that if we're trying to create an empty value for an
2020                                                         // array < 32 entries that all-0s may be a valid state.
2021                                                         unimplemented!();
2022                                                 }
2023                                                 let arrty = format!("[u8; {}]", i.base10_digits());
2024                                                 write!(w, "{}", self.to_c_conversion_inline_prefix_from_path(&arrty, false, false).unwrap()).unwrap();
2025                                                 write!(w, "[0; {}]", i.base10_digits()).unwrap();
2026                                                 write!(w, "{}", self.to_c_conversion_inline_suffix_from_path(&arrty, false, false).unwrap()).unwrap();
2027                                         } else { unimplemented!(); }
2028                                 } else { unimplemented!(); }
2029                         }
2030                         _ => unimplemented!(),
2031                 }
2032         }
2033
2034         /// Prints a suffix to determine if a variable is empty (ie was set by write_empty_rust_val).
2035         /// See EmptyValExpectedTy for information on return types.
2036         fn write_empty_rust_val_check_suffix<W: std::io::Write>(&self, generics: Option<&GenericTypes>, w: &mut W, t: &syn::Type) -> EmptyValExpectedTy {
2037                 match t {
2038                         syn::Type::Reference(r) => {
2039                                 return self.write_empty_rust_val_check_suffix(generics, w, &*r.elem);
2040                         },
2041                         syn::Type::Path(p) => {
2042                                 let resolved = self.resolve_path(&p.path, generics);
2043                                 if self.crate_types.opaques.get(&resolved).is_some() {
2044                                         write!(w, ".inner.is_null()").unwrap();
2045                                         EmptyValExpectedTy::NonPointer
2046                                 } else {
2047                                         if let Some(suffix) = self.empty_val_check_suffix_from_path(&resolved) {
2048                                                 write!(w, "{}", suffix).unwrap();
2049                                                 // We may eventually need to allow empty_val_check_suffix_from_path to specify if we need a deref or not
2050                                                 EmptyValExpectedTy::NonPointer
2051                                         } else {
2052                                                 write!(w, ".is_none()").unwrap();
2053                                                 EmptyValExpectedTy::OptionType
2054                                         }
2055                                 }
2056                         },
2057                         syn::Type::Array(a) => {
2058                                 if let syn::Expr::Lit(l) = &a.len {
2059                                         if let syn::Lit::Int(i) = &l.lit {
2060                                                 write!(w, ".data == [0; {}]", i.base10_digits()).unwrap();
2061                                                 EmptyValExpectedTy::NonPointer
2062                                         } else { unimplemented!(); }
2063                                 } else { unimplemented!(); }
2064                         },
2065                         syn::Type::Slice(_) => {
2066                                 // Option<[]> always implies that we want to treat len() == 0 differently from
2067                                 // None, so we always map an Option<[]> into a pointer.
2068                                 write!(w, " == core::ptr::null_mut()").unwrap();
2069                                 EmptyValExpectedTy::ReferenceAsPointer
2070                         },
2071                         _ => unimplemented!(),
2072                 }
2073         }
2074
2075         /// Prints a suffix to determine if a variable is empty (ie was set by write_empty_rust_val).
2076         pub fn write_empty_rust_val_check<W: std::io::Write>(&self, generics: Option<&GenericTypes>, w: &mut W, t: &syn::Type, var_access: &str) {
2077                 match t {
2078                         syn::Type::Reference(r) => {
2079                                 self.write_empty_rust_val_check(generics, w, &*r.elem, var_access);
2080                         },
2081                         syn::Type::Path(_) => {
2082                                 write!(w, "{}", var_access).unwrap();
2083                                 self.write_empty_rust_val_check_suffix(generics, w, t);
2084                         },
2085                         syn::Type::Array(a) => {
2086                                 if let syn::Expr::Lit(l) = &a.len {
2087                                         if let syn::Lit::Int(i) = &l.lit {
2088                                                 let arrty = format!("[u8; {}]", i.base10_digits());
2089                                                 // We don't (yet) support a new-var conversion here.
2090                                                 assert!(self.from_c_conversion_new_var_from_path(&arrty, false).is_none());
2091                                                 write!(w, "{}{}{}",
2092                                                         self.from_c_conversion_prefix_from_path(&arrty, false).unwrap(),
2093                                                         var_access,
2094                                                         self.from_c_conversion_suffix_from_path(&arrty, false).unwrap()).unwrap();
2095                                                 self.write_empty_rust_val_check_suffix(generics, w, t);
2096                                         } else { unimplemented!(); }
2097                                 } else { unimplemented!(); }
2098                         }
2099                         _ => unimplemented!(),
2100                 }
2101         }
2102
2103         // ********************************
2104         // *** Type conversion printing ***
2105         // ********************************
2106
2107         /// Returns true we if can just skip passing this to C entirely
2108         pub fn skip_arg(&self, t: &syn::Type, generics: Option<&GenericTypes>) -> bool {
2109                 match t {
2110                         syn::Type::Path(p) => {
2111                                 if p.qself.is_some() { unimplemented!(); }
2112                                 if let Some(full_path) = self.maybe_resolve_path(&p.path, generics) {
2113                                         self.skip_path(&full_path)
2114                                 } else { false }
2115                         },
2116                         syn::Type::Reference(r) => {
2117                                 self.skip_arg(&*r.elem, generics)
2118                         },
2119                         _ => false,
2120                 }
2121         }
2122         pub fn no_arg_to_rust<W: std::io::Write>(&self, w: &mut W, t: &syn::Type, generics: Option<&GenericTypes>) {
2123                 match t {
2124                         syn::Type::Path(p) => {
2125                                 if p.qself.is_some() { unimplemented!(); }
2126                                 if let Some(full_path) = self.maybe_resolve_path(&p.path, generics) {
2127                                         write!(w, "{}", self.no_arg_path_to_rust(&full_path)).unwrap();
2128                                 }
2129                         },
2130                         syn::Type::Reference(r) => {
2131                                 self.no_arg_to_rust(w, &*r.elem, generics);
2132                         },
2133                         _ => {},
2134                 }
2135         }
2136
2137         fn write_conversion_inline_intern<W: std::io::Write,
2138                         LP: Fn(&str, bool, bool) -> Option<String>, DL: Fn(&mut W, &DeclType, &str, bool, bool), SC: Fn(bool, Option<&str>) -> String>
2139                         (&self, w: &mut W, t: &syn::Type, generics: Option<&GenericTypes>, is_ref: bool, is_mut: bool, ptr_for_ref: bool,
2140                          tupleconv: &str, prefix: bool, sliceconv: SC, path_lookup: LP, decl_lookup: DL) {
2141                 match generics.resolve_type(t) {
2142                         syn::Type::Reference(r) => {
2143                                 self.write_conversion_inline_intern(w, &*r.elem, generics, true, r.mutability.is_some(),
2144                                         ptr_for_ref, tupleconv, prefix, sliceconv, path_lookup, decl_lookup);
2145                         },
2146                         syn::Type::Path(p) => {
2147                                 if p.qself.is_some() {
2148                                         unimplemented!();
2149                                 }
2150
2151                                 let resolved_path = self.resolve_path(&p.path, generics);
2152                                 if let Some(aliased_type) = self.crate_types.type_aliases.get(&resolved_path) {
2153                                         return self.write_conversion_inline_intern(w, aliased_type, None, is_ref, is_mut, ptr_for_ref, tupleconv, prefix, sliceconv, path_lookup, decl_lookup);
2154                                 } else if self.is_primitive(&resolved_path) {
2155                                         if is_ref && prefix {
2156                                                 write!(w, "*").unwrap();
2157                                         }
2158                                 } else if let Some(c_type) = path_lookup(&resolved_path, is_ref, ptr_for_ref) {
2159                                         write!(w, "{}", c_type).unwrap();
2160                                 } else if let Some((_, generics)) = self.crate_types.opaques.get(&resolved_path) {
2161                                         decl_lookup(w, &DeclType::StructImported { generics: &generics }, &resolved_path, is_ref, is_mut);
2162                                 } else if self.crate_types.mirrored_enums.get(&resolved_path).is_some() {
2163                                         decl_lookup(w, &DeclType::MirroredEnum, &resolved_path, is_ref, is_mut);
2164                                 } else if let Some(t) = self.crate_types.traits.get(&resolved_path) {
2165                                         decl_lookup(w, &DeclType::Trait(t), &resolved_path, is_ref, is_mut);
2166                                 } else if let Some(ident) = single_ident_generic_path_to_ident(&p.path) {
2167                                         if let Some(decl_type) = self.types.maybe_resolve_declared(ident) {
2168                                                 decl_lookup(w, decl_type, &self.maybe_resolve_ident(ident).unwrap(), is_ref, is_mut);
2169                                         } else { unimplemented!(); }
2170                                 } else {
2171                                         if let Some(trait_impls) = self.crate_types.traits_impld.get(&resolved_path) {
2172                                                 if trait_impls.len() == 1 {
2173                                                         // If this is a no-export'd crate and there's only one implementation
2174                                                         // in the whole crate, just treat it as a reference to whatever the
2175                                                         // implementor is.
2176                                                         let implementor = self.crate_types.opaques.get(&trait_impls[0]).unwrap();
2177                                                         decl_lookup(w, &DeclType::StructImported { generics: &implementor.1 }, &trait_impls[0], true, is_mut);
2178                                                         return;
2179                                                 }
2180                                         }
2181                                         unimplemented!();
2182                                 }
2183                         },
2184                         syn::Type::Array(a) => {
2185                                 if let syn::Type::Path(p) = &*a.elem {
2186                                         let inner_ty = self.resolve_path(&p.path, generics);
2187                                         if let syn::Expr::Lit(l) = &a.len {
2188                                                 if let syn::Lit::Int(i) = &l.lit {
2189                                                         write!(w, "{}", path_lookup(&format!("[{}; {}]", inner_ty, i.base10_digits()), is_ref, ptr_for_ref).unwrap()).unwrap();
2190                                                 } else { unimplemented!(); }
2191                                         } else { unimplemented!(); }
2192                                 } else { unimplemented!(); }
2193                         },
2194                         syn::Type::Slice(s) => {
2195                                 // We assume all slices contain only literals or references.
2196                                 // This may result in some outputs not compiling.
2197                                 if let syn::Type::Path(p) = &*s.elem {
2198                                         let resolved = self.resolve_path(&p.path, generics);
2199                                         if self.is_primitive(&resolved) {
2200                                                 write!(w, "{}", path_lookup("[u8]", is_ref, ptr_for_ref).unwrap()).unwrap();
2201                                         } else {
2202                                                 write!(w, "{}", sliceconv(true, None)).unwrap();
2203                                         }
2204                                 } else if let syn::Type::Reference(r) = &*s.elem {
2205                                         if let syn::Type::Path(p) = &*r.elem {
2206                                                 write!(w, "{}", sliceconv(self.c_type_has_inner_from_path(&self.resolve_path(&p.path, generics)), None)).unwrap();
2207                                         } else if let syn::Type::Slice(_) = &*r.elem {
2208                                                 write!(w, "{}", sliceconv(false, None)).unwrap();
2209                                         } else { unimplemented!(); }
2210                                 } else if let syn::Type::Tuple(t) = &*s.elem {
2211                                         assert!(!t.elems.is_empty());
2212                                         if prefix {
2213                                                 write!(w, "{}", sliceconv(false, None)).unwrap();
2214                                         } else {
2215                                                 let mut needs_map = false;
2216                                                 for e in t.elems.iter() {
2217                                                         if let syn::Type::Reference(_) = e {
2218                                                                 needs_map = true;
2219                                                         }
2220                                                 }
2221                                                 if needs_map {
2222                                                         let mut map_str = Vec::new();
2223                                                         write!(&mut map_str, ".map(|(").unwrap();
2224                                                         for i in 0..t.elems.len() {
2225                                                                 write!(&mut map_str, "{}{}", if i != 0 { ", " } else { "" }, ('a' as u8 + i as u8) as char).unwrap();
2226                                                         }
2227                                                         write!(&mut map_str, ")| (").unwrap();
2228                                                         for (idx, e) in t.elems.iter().enumerate() {
2229                                                                 if let syn::Type::Reference(_) = e {
2230                                                                         write!(&mut map_str, "{}{}", if idx != 0 { ", " } else { "" }, (idx as u8 + 'a' as u8) as char).unwrap();
2231                                                                 } else if let syn::Type::Path(_) = e {
2232                                                                         write!(&mut map_str, "{}*{}", if idx != 0 { ", " } else { "" }, (idx as u8 + 'a' as u8) as char).unwrap();
2233                                                                 } else { unimplemented!(); }
2234                                                         }
2235                                                         write!(&mut map_str, "))").unwrap();
2236                                                         write!(w, "{}", sliceconv(false, Some(&String::from_utf8(map_str).unwrap()))).unwrap();
2237                                                 } else {
2238                                                         write!(w, "{}", sliceconv(false, None)).unwrap();
2239                                                 }
2240                                         }
2241                                 } else if let syn::Type::Array(_) = &*s.elem {
2242                                         write!(w, "{}", sliceconv(false, Some(".map(|a| *a)"))).unwrap();
2243                                 } else { unimplemented!(); }
2244                         },
2245                         syn::Type::Tuple(t) => {
2246                                 if t.elems.is_empty() {
2247                                         // cbindgen has poor support for (), see, eg https://github.com/eqrion/cbindgen/issues/527
2248                                         // so work around it by just pretending its a 0u8
2249                                         write!(w, "{}", tupleconv).unwrap();
2250                                 } else {
2251                                         if prefix { write!(w, "local_").unwrap(); }
2252                                 }
2253                         },
2254                         _ => unimplemented!(),
2255                 }
2256         }
2257
2258         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) {
2259                 self.write_conversion_inline_intern(w, t, generics, is_ref, false, ptr_for_ref, "() /*", true, |_, _| "local_".to_owned(),
2260                                 |a, b, c| self.to_c_conversion_inline_prefix_from_path(a, b, c),
2261                                 |w, decl_type, decl_path, is_ref, _is_mut| {
2262                                         match decl_type {
2263                                                 DeclType::MirroredEnum if is_ref && ptr_for_ref => write!(w, "crate::{}::from_native(", decl_path).unwrap(),
2264                                                 DeclType::MirroredEnum if is_ref => write!(w, "&crate::{}::from_native(", decl_path).unwrap(),
2265                                                 DeclType::MirroredEnum => write!(w, "crate::{}::native_into(", decl_path).unwrap(),
2266                                                 DeclType::EnumIgnored {..}|DeclType::StructImported {..} if is_ref && from_ptr => {
2267                                                         if !ptr_for_ref { write!(w, "&").unwrap(); }
2268                                                         write!(w, "crate::{} {{ inner: unsafe {{ (", decl_path).unwrap()
2269                                                 },
2270                                                 DeclType::EnumIgnored {..}|DeclType::StructImported {..} if is_ref => {
2271                                                         if !ptr_for_ref { write!(w, "&").unwrap(); }
2272                                                         write!(w, "crate::{} {{ inner: unsafe {{ ObjOps::nonnull_ptr_to_inner((", decl_path).unwrap()
2273                                                 },
2274                                                 DeclType::EnumIgnored {..}|DeclType::StructImported {..} if !is_ref && from_ptr =>
2275                                                         write!(w, "crate::{} {{ inner: ", decl_path).unwrap(),
2276                                                 DeclType::EnumIgnored {..}|DeclType::StructImported {..} if !is_ref =>
2277                                                         write!(w, "crate::{} {{ inner: ObjOps::heap_alloc(", decl_path).unwrap(),
2278                                                 DeclType::Trait(_) if is_ref => write!(w, "").unwrap(),
2279                                                 DeclType::Trait(_) if !is_ref => write!(w, "Into::into(").unwrap(),
2280                                                 _ => panic!("{:?}", decl_path),
2281                                         }
2282                                 });
2283         }
2284         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) {
2285                 self.write_to_c_conversion_inline_prefix_inner(w, t, generics, false, ptr_for_ref, false);
2286         }
2287         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) {
2288                 self.write_conversion_inline_intern(w, t, generics, is_ref, false, ptr_for_ref, "*/", false, |_, _| ".into()".to_owned(),
2289                                 |a, b, c| self.to_c_conversion_inline_suffix_from_path(a, b, c),
2290                                 |w, decl_type, full_path, is_ref, _is_mut| match decl_type {
2291                                         DeclType::MirroredEnum => write!(w, ")").unwrap(),
2292                                         DeclType::EnumIgnored { generics }|DeclType::StructImported { generics } if is_ref => {
2293                                                 write!(w, " as *const {}<", full_path).unwrap();
2294                                                 for param in generics.params.iter() {
2295                                                         if let syn::GenericParam::Lifetime(_) = param {
2296                                                                 write!(w, "'_, ").unwrap();
2297                                                         } else {
2298                                                                 write!(w, "_, ").unwrap();
2299                                                         }
2300                                                 }
2301                                                 if from_ptr {
2302                                                         write!(w, ">) as *mut _ }}, is_owned: false }}").unwrap();
2303                                                 } else {
2304                                                         write!(w, ">) as *mut _) }}, is_owned: false }}").unwrap();
2305                                                 }
2306                                         },
2307                                         DeclType::EnumIgnored {..}|DeclType::StructImported {..} if !is_ref && from_ptr =>
2308                                                 write!(w, ", is_owned: true }}").unwrap(),
2309                                         DeclType::EnumIgnored {..}|DeclType::StructImported {..} if !is_ref => write!(w, "), is_owned: true }}").unwrap(),
2310                                         DeclType::Trait(_) if is_ref => {},
2311                                         DeclType::Trait(_) => {
2312                                                 // This is used when we're converting a concrete Rust type into a C trait
2313                                                 // for use when a Rust trait method returns an associated type.
2314                                                 // Because all of our C traits implement From<RustTypesImplementingTraits>
2315                                                 // we can just call .into() here and be done.
2316                                                 write!(w, ")").unwrap()
2317                                         },
2318                                         _ => unimplemented!(),
2319                                 });
2320         }
2321         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) {
2322                 self.write_to_c_conversion_inline_suffix_inner(w, t, generics, false, ptr_for_ref, false);
2323         }
2324
2325         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) {
2326                 self.write_conversion_inline_intern(w, t, generics, is_ref, false, false, "() /*", true, |_, _| "&local_".to_owned(),
2327                                 |a, b, _c| self.from_c_conversion_prefix_from_path(a, b),
2328                                 |w, decl_type, _full_path, is_ref, _is_mut| match decl_type {
2329                                         DeclType::StructImported {..} if is_ref => write!(w, "").unwrap(),
2330                                         DeclType::StructImported {..} if !is_ref => write!(w, "*unsafe {{ Box::from_raw(").unwrap(),
2331                                         DeclType::MirroredEnum if is_ref => write!(w, "&").unwrap(),
2332                                         DeclType::MirroredEnum => {},
2333                                         DeclType::Trait(_) => {},
2334                                         _ => unimplemented!(),
2335                                 });
2336         }
2337         pub fn write_from_c_conversion_prefix<W: std::io::Write>(&self, w: &mut W, t: &syn::Type, generics: Option<&GenericTypes>) {
2338                 self.write_from_c_conversion_prefix_inner(w, t, generics, false, false);
2339         }
2340         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) {
2341                 self.write_conversion_inline_intern(w, t, generics, is_ref, false, false, "*/", false,
2342                                 |has_inner, map_str_opt| match (has_inner, map_str_opt) {
2343                                         (false, Some(map_str)) => format!(".iter(){}.collect::<Vec<_>>()[..]", map_str),
2344                                         (false, None) => ".iter().collect::<Vec<_>>()[..]".to_owned(),
2345                                         (true, None) => "[..]".to_owned(),
2346                                         (true, Some(_)) => unreachable!(),
2347                                 },
2348                                 |a, b, _c| self.from_c_conversion_suffix_from_path(a, b),
2349                                 |w, decl_type, _full_path, is_ref, is_mut| match decl_type {
2350                                         DeclType::StructImported {..} if is_ref && ptr_for_ref => write!(w, "XXX unimplemented").unwrap(),
2351                                         DeclType::StructImported {..} if is_mut && is_ref => write!(w, ".get_native_mut_ref()").unwrap(),
2352                                         DeclType::StructImported {..} if is_ref => write!(w, ".get_native_ref()").unwrap(),
2353                                         DeclType::StructImported {..} if !is_ref => write!(w, ".take_inner()) }}").unwrap(),
2354                                         DeclType::MirroredEnum if is_ref => write!(w, ".to_native()").unwrap(),
2355                                         DeclType::MirroredEnum => write!(w, ".into_native()").unwrap(),
2356                                         DeclType::Trait(_) => {},
2357                                         _ => unimplemented!(),
2358                                 });
2359         }
2360         pub fn write_from_c_conversion_suffix<W: std::io::Write>(&self, w: &mut W, t: &syn::Type, generics: Option<&GenericTypes>) {
2361                 self.write_from_c_conversion_suffix_inner(w, t, generics, false, false);
2362         }
2363         // Note that compared to the above conversion functions, the following two are generally
2364         // significantly undertested:
2365         pub fn write_from_c_conversion_to_ref_prefix<W: std::io::Write>(&self, w: &mut W, t: &syn::Type, generics: Option<&GenericTypes>) {
2366                 self.write_conversion_inline_intern(w, t, generics, false, false, false, "() /*", true, |_, _| "&local_".to_owned(),
2367                                 |a, b, _c| {
2368                                         if let Some(conv) = self.from_c_conversion_prefix_from_path(a, b) {
2369                                                 Some(format!("&{}", conv))
2370                                         } else { None }
2371                                 },
2372                                 |w, decl_type, _full_path, is_ref, _is_mut| match decl_type {
2373                                         DeclType::StructImported {..} if !is_ref => write!(w, "").unwrap(),
2374                                         _ => unimplemented!(),
2375                                 });
2376         }
2377         pub fn write_from_c_conversion_to_ref_suffix<W: std::io::Write>(&self, w: &mut W, t: &syn::Type, generics: Option<&GenericTypes>) {
2378                 self.write_conversion_inline_intern(w, t, generics, false, false, false, "*/", false,
2379                                 |has_inner, map_str_opt| match (has_inner, map_str_opt) {
2380                                         (false, Some(map_str)) => format!(".iter(){}.collect::<Vec<_>>()[..]", map_str),
2381                                         (false, None) => ".iter().collect::<Vec<_>>()[..]".to_owned(),
2382                                         (true, None) => "[..]".to_owned(),
2383                                         (true, Some(_)) => unreachable!(),
2384                                 },
2385                                 |a, b, _c| self.from_c_conversion_suffix_from_path(a, b),
2386                                 |w, decl_type, _full_path, is_ref, _is_mut| match decl_type {
2387                                         DeclType::StructImported {..} if !is_ref => write!(w, ".get_native_ref()").unwrap(),
2388                                         _ => unimplemented!(),
2389                                 });
2390         }
2391
2392         fn write_conversion_new_var_intern<'b, W: std::io::Write,
2393                 LP: Fn(&str, bool) -> Option<(&str, &str)>,
2394                 LC: Fn(&str, bool, Option<&syn::Type>, &syn::Ident, &str) ->  Option<(&'b str, Vec<(String, String)>, &'b str, ContainerPrefixLocation)>,
2395                 VP: Fn(&mut W, &syn::Type, Option<&GenericTypes>, bool, bool, bool),
2396                 VS: Fn(&mut W, &syn::Type, Option<&GenericTypes>, bool, bool, bool)>
2397                         (&self, w: &mut W, ident: &syn::Ident, var: &str, t: &syn::Type, generics: Option<&GenericTypes>,
2398                          mut is_ref: bool, mut ptr_for_ref: bool, to_c: bool, from_ownable_ref: bool,
2399                          path_lookup: &LP, container_lookup: &LC, var_prefix: &VP, var_suffix: &VS) -> bool {
2400
2401                 macro_rules! convert_container {
2402                         ($container_type: expr, $args_len: expr, $args_iter: expr) => { {
2403                                 // For slices (and Options), we refuse to directly map them as is_ref when they
2404                                 // aren't opaque types containing an inner pointer. This is due to the fact that,
2405                                 // in both cases, the actual higher-level type is non-is_ref.
2406                                 let (ty_has_inner, ty_is_trait) = if $args_len == 1 {
2407                                         let ty = $args_iter().next().unwrap();
2408                                         if $container_type == "Slice" && to_c {
2409                                                 // "To C ptr_for_ref" means "return the regular object with is_owned
2410                                                 // set to false", which is totally what we want in a slice if we're about to
2411                                                 // set ty_has_inner.
2412                                                 ptr_for_ref = true;
2413                                         }
2414                                         if let syn::Type::Reference(t) = ty {
2415                                                 if let syn::Type::Path(p) = &*t.elem {
2416                                                         let resolved = self.resolve_path(&p.path, generics);
2417                                                         (self.c_type_has_inner_from_path(&resolved), self.crate_types.traits.get(&resolved).is_some())
2418                                                 } else { (false, false) }
2419                                         } else if let syn::Type::Path(p) = ty {
2420                                                 let resolved = self.resolve_path(&p.path, generics);
2421                                                 (self.c_type_has_inner_from_path(&resolved), self.crate_types.traits.get(&resolved).is_some())
2422                                         } else { (false, false) }
2423                                 } else { (true, false) };
2424
2425                                 // Options get a bunch of special handling, since in general we map Option<>al
2426                                 // types into the same C type as non-Option-wrapped types. This ends up being
2427                                 // pretty manual here and most of the below special-cases are for Options.
2428                                 let mut needs_ref_map = false;
2429                                 let mut only_contained_type = None;
2430                                 let mut only_contained_type_nonref = None;
2431                                 let mut only_contained_has_inner = false;
2432                                 let mut contains_slice = false;
2433                                 if $args_len == 1 {
2434                                         only_contained_has_inner = ty_has_inner;
2435                                         let arg = $args_iter().next().unwrap();
2436                                         if let syn::Type::Reference(t) = arg {
2437                                                 only_contained_type = Some(arg);
2438                                                 only_contained_type_nonref = Some(&*t.elem);
2439                                                 if let syn::Type::Path(_) = &*t.elem {
2440                                                         is_ref = true;
2441                                                 } else if let syn::Type::Slice(_) = &*t.elem {
2442                                                         contains_slice = true;
2443                                                 } else { return false; }
2444                                                 // If the inner element contains an inner pointer, we will just use that,
2445                                                 // avoiding the need to map elements to references. Otherwise we'll need to
2446                                                 // do an extra mapping step.
2447                                                 needs_ref_map = !only_contained_has_inner && !ty_is_trait && $container_type == "Option";
2448                                         } else {
2449                                                 only_contained_type = Some(arg);
2450                                                 only_contained_type_nonref = Some(arg);
2451                                         }
2452                                 }
2453
2454                                 if let Some((prefix, conversions, suffix, prefix_location)) = container_lookup(&$container_type, is_ref, only_contained_type, ident, var) {
2455                                         assert_eq!(conversions.len(), $args_len);
2456                                         write!(w, "let mut local_{}{} = ", ident,
2457                                                 if (!to_c && needs_ref_map) || (to_c && $container_type == "Option" && contains_slice) {"_base"} else { "" }).unwrap();
2458                                         if prefix_location == ContainerPrefixLocation::OutsideConv {
2459                                                 var_prefix(w, $args_iter().next().unwrap(), generics, is_ref, true, true);
2460                                         }
2461                                         write!(w, "{}{}", prefix, var).unwrap();
2462
2463                                         for ((pfx, var_name), (idx, ty)) in conversions.iter().zip($args_iter().enumerate()) {
2464                                                 let mut var = std::io::Cursor::new(Vec::new());
2465                                                 write!(&mut var, "{}", var_name).unwrap();
2466                                                 let var_access = String::from_utf8(var.into_inner()).unwrap();
2467
2468                                                 let conv_ty = if needs_ref_map { only_contained_type_nonref.as_ref().unwrap() } else { ty };
2469
2470                                                 write!(w, "{} {{ ", pfx).unwrap();
2471                                                 let new_var_name = format!("{}_{}", ident, idx);
2472                                                 let new_var = self.write_conversion_new_var_intern(w, &format_ident!("{}", new_var_name),
2473                                                                 &var_access, conv_ty, generics, contains_slice || (is_ref && ty_has_inner), ptr_for_ref,
2474                                                                 to_c, from_ownable_ref, path_lookup, container_lookup, var_prefix, var_suffix);
2475                                                 if new_var { write!(w, " ").unwrap(); }
2476
2477                                                 if prefix_location == ContainerPrefixLocation::PerConv {
2478                                                         var_prefix(w, conv_ty, generics, is_ref && ty_has_inner, ptr_for_ref, false);
2479                                                 } else if !is_ref && !needs_ref_map && to_c && only_contained_has_inner {
2480                                                         write!(w, "ObjOps::heap_alloc(").unwrap();
2481                                                 }
2482
2483                                                 write!(w, "{}{}", if contains_slice && !to_c { "local_" } else { "" }, if new_var { new_var_name } else { var_access }).unwrap();
2484                                                 if prefix_location == ContainerPrefixLocation::PerConv {
2485                                                         var_suffix(w, conv_ty, generics, is_ref && ty_has_inner, ptr_for_ref, false);
2486                                                 } else if !is_ref && !needs_ref_map && to_c && only_contained_has_inner {
2487                                                         write!(w, ")").unwrap();
2488                                                 }
2489                                                 write!(w, " }}").unwrap();
2490                                         }
2491                                         write!(w, "{}", suffix).unwrap();
2492                                         if prefix_location == ContainerPrefixLocation::OutsideConv {
2493                                                 var_suffix(w, $args_iter().next().unwrap(), generics, is_ref, ptr_for_ref, true);
2494                                         }
2495                                         write!(w, ";").unwrap();
2496                                         if !to_c && needs_ref_map {
2497                                                 write!(w, " let mut local_{} = local_{}_base.as_ref()", ident, ident).unwrap();
2498                                                 if contains_slice {
2499                                                         write!(w, ".map(|a| &a[..])").unwrap();
2500                                                 }
2501                                                 write!(w, ";").unwrap();
2502                                         } else if to_c && $container_type == "Option" && contains_slice {
2503                                                 write!(w, " let mut local_{} = *local_{}_base;", ident, ident).unwrap();
2504                                         }
2505                                         return true;
2506                                 }
2507                         } }
2508                 }
2509
2510                 match generics.resolve_type(t) {
2511                         syn::Type::Reference(r) => {
2512                                 if let syn::Type::Slice(_) = &*r.elem {
2513                                         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)
2514                                 } else {
2515                                         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)
2516                                 }
2517                         },
2518                         syn::Type::Path(p) => {
2519                                 if p.qself.is_some() {
2520                                         unimplemented!();
2521                                 }
2522                                 let resolved_path = self.resolve_path(&p.path, generics);
2523                                 if let Some(aliased_type) = self.crate_types.type_aliases.get(&resolved_path) {
2524                                         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);
2525                                 }
2526                                 if self.is_known_container(&resolved_path, is_ref) || self.is_path_transparent_container(&p.path, generics, is_ref) {
2527                                         if let syn::PathArguments::AngleBracketed(args) = &p.path.segments.iter().next().unwrap().arguments {
2528                                                 convert_container!(resolved_path, args.args.len(), || args.args.iter().map(|arg| {
2529                                                         if let syn::GenericArgument::Type(ty) = arg {
2530                                                                 generics.resolve_type(ty)
2531                                                         } else { unimplemented!(); }
2532                                                 }));
2533                                         } else { unimplemented!(); }
2534                                 }
2535                                 if self.is_primitive(&resolved_path) {
2536                                         false
2537                                 } else if let Some(ty_ident) = single_ident_generic_path_to_ident(&p.path) {
2538                                         if let Some((prefix, suffix)) = path_lookup(&resolved_path, is_ref) {
2539                                                 write!(w, "let mut local_{} = {}{}{};", ident, prefix, var, suffix).unwrap();
2540                                                 true
2541                                         } else if self.types.maybe_resolve_declared(ty_ident).is_some() {
2542                                                 false
2543                                         } else { false }
2544                                 } else { false }
2545                         },
2546                         syn::Type::Array(_) => {
2547                                 // We assume all arrays contain only primitive types.
2548                                 // This may result in some outputs not compiling.
2549                                 false
2550                         },
2551                         syn::Type::Slice(s) => {
2552                                 if let syn::Type::Path(p) = &*s.elem {
2553                                         let resolved = self.resolve_path(&p.path, generics);
2554                                         if self.is_primitive(&resolved) {
2555                                                 let slice_path = format!("[{}]", resolved);
2556                                                 if let Some((prefix, suffix)) = path_lookup(&slice_path, true) {
2557                                                         write!(w, "let mut local_{} = {}{}{};", ident, prefix, var, suffix).unwrap();
2558                                                         true
2559                                                 } else { false }
2560                                         } else {
2561                                                 let tyref = [&*s.elem];
2562                                                 if to_c {
2563                                                         // If we're converting from a slice to a Vec, assume we can clone the
2564                                                         // elements and clone them into a new Vec first. Next we'll walk the
2565                                                         // new Vec here and convert them to C types.
2566                                                         write!(w, "let mut local_{}_clone = Vec::new(); local_{}_clone.extend_from_slice({}); let mut {} = local_{}_clone; ", ident, ident, ident, ident, ident).unwrap();
2567                                                 }
2568                                                 is_ref = false;
2569                                                 convert_container!("Vec", 1, || tyref.iter().map(|t| generics.resolve_type(*t)));
2570                                                 unimplemented!("convert_container should return true as container_lookup should succeed for slices");
2571                                         }
2572                                 } else if let syn::Type::Reference(ty) = &*s.elem {
2573                                         let tyref = if from_ownable_ref || !to_c { [&*ty.elem] } else { [&*s.elem] };
2574                                         is_ref = true;
2575                                         convert_container!("Slice", 1, || tyref.iter().map(|t| generics.resolve_type(*t)));
2576                                         unimplemented!("convert_container should return true as container_lookup should succeed for slices");
2577                                 } else if let syn::Type::Tuple(t) = &*s.elem {
2578                                         // When mapping into a temporary new var, we need to own all the underlying objects.
2579                                         // Thus, we drop any references inside the tuple and convert with non-reference types.
2580                                         let mut elems = syn::punctuated::Punctuated::new();
2581                                         for elem in t.elems.iter() {
2582                                                 if let syn::Type::Reference(r) = elem {
2583                                                         elems.push((*r.elem).clone());
2584                                                 } else {
2585                                                         elems.push(elem.clone());
2586                                                 }
2587                                         }
2588                                         let ty = [syn::Type::Tuple(syn::TypeTuple {
2589                                                 paren_token: t.paren_token, elems
2590                                         })];
2591                                         is_ref = false;
2592                                         ptr_for_ref = true;
2593                                         convert_container!("Slice", 1, || ty.iter());
2594                                         unimplemented!("convert_container should return true as container_lookup should succeed for slices");
2595                                 } else if let syn::Type::Array(_) = &*s.elem {
2596                                         is_ref = false;
2597                                         ptr_for_ref = true;
2598                                         let arr_elem = [(*s.elem).clone()];
2599                                         convert_container!("Slice", 1, || arr_elem.iter());
2600                                         unimplemented!("convert_container should return true as container_lookup should succeed for slices");
2601                                 } else { unimplemented!() }
2602                         },
2603                         syn::Type::Tuple(t) => {
2604                                 if !t.elems.is_empty() {
2605                                         // We don't (yet) support tuple elements which cannot be converted inline
2606                                         write!(w, "let (").unwrap();
2607                                         for idx in 0..t.elems.len() {
2608                                                 if idx != 0 { write!(w, ", ").unwrap(); }
2609                                                 write!(w, "{} orig_{}_{}", if is_ref { "ref" } else { "mut" }, ident, idx).unwrap();
2610                                         }
2611                                         write!(w, ") = {}{}; ", var, if !to_c { ".to_rust()" } else { "" }).unwrap();
2612                                         // Like other template types, tuples are always mapped as their non-ref
2613                                         // versions for types which have different ref mappings. Thus, we convert to
2614                                         // non-ref versions and handle opaque types with inner pointers manually.
2615                                         for (idx, elem) in t.elems.iter().enumerate() {
2616                                                 if let syn::Type::Path(p) = elem {
2617                                                         let v_name = format!("orig_{}_{}", ident, idx);
2618                                                         let tuple_elem_ident = format_ident!("{}", &v_name);
2619                                                         if self.write_conversion_new_var_intern(w, &tuple_elem_ident, &v_name, elem, generics,
2620                                                                         false, ptr_for_ref, to_c, from_ownable_ref,
2621                                                                         path_lookup, container_lookup, var_prefix, var_suffix) {
2622                                                                 write!(w, " ").unwrap();
2623                                                                 // Opaque types with inner pointers shouldn't ever create new stack
2624                                                                 // variables, so we don't handle it and just assert that it doesn't
2625                                                                 // here.
2626                                                                 assert!(!self.c_type_has_inner_from_path(&self.resolve_path(&p.path, generics)));
2627                                                         }
2628                                                 }
2629                                         }
2630                                         write!(w, "let mut local_{} = (", ident).unwrap();
2631                                         for (idx, elem) in t.elems.iter().enumerate() {
2632                                                 let real_elem = generics.resolve_type(&elem);
2633                                                 let ty_has_inner = {
2634                                                                 if to_c {
2635                                                                         // "To C ptr_for_ref" means "return the regular object with
2636                                                                         // is_owned set to false", which is totally what we want
2637                                                                         // if we're about to set ty_has_inner.
2638                                                                         ptr_for_ref = true;
2639                                                                 }
2640                                                                 if let syn::Type::Reference(t) = real_elem {
2641                                                                         if let syn::Type::Path(p) = &*t.elem {
2642                                                                                 self.c_type_has_inner_from_path(&self.resolve_path(&p.path, generics))
2643                                                                         } else { false }
2644                                                                 } else if let syn::Type::Path(p) = real_elem {
2645                                                                         self.c_type_has_inner_from_path(&self.resolve_path(&p.path, generics))
2646                                                                 } else { false }
2647                                                         };
2648                                                 if idx != 0 { write!(w, ", ").unwrap(); }
2649                                                 var_prefix(w, real_elem, generics, is_ref && ty_has_inner, ptr_for_ref, false);
2650                                                 if is_ref && ty_has_inner {
2651                                                         // For ty_has_inner, the regular var_prefix mapping will take a
2652                                                         // reference, so deref once here to make sure we keep the original ref.
2653                                                         write!(w, "*").unwrap();
2654                                                 }
2655                                                 write!(w, "orig_{}_{}", ident, idx).unwrap();
2656                                                 if is_ref && !ty_has_inner {
2657                                                         // If we don't have an inner variable's reference to maintain, just
2658                                                         // hope the type is Clonable and use that.
2659                                                         write!(w, ".clone()").unwrap();
2660                                                 }
2661                                                 var_suffix(w, real_elem, generics, is_ref && ty_has_inner, ptr_for_ref, false);
2662                                         }
2663                                         write!(w, "){};", if to_c { ".into()" } else { "" }).unwrap();
2664                                         true
2665                                 } else { false }
2666                         },
2667                         _ => unimplemented!(),
2668                 }
2669         }
2670
2671         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 {
2672                 self.write_conversion_new_var_intern(w, ident, var_access, t, generics, from_ownable_ref, ptr_for_ref, true, from_ownable_ref,
2673                         &|a, b| self.to_c_conversion_new_var_from_path(a, b),
2674                         &|a, b, c, d, e| self.to_c_conversion_container_new_var(generics, a, b, c, d, e),
2675                         // We force ptr_for_ref here since we can't generate a ref on one line and use it later
2676                         &|a, b, c, d, e, f| self.write_to_c_conversion_inline_prefix_inner(a, b, c, d, e, f),
2677                         &|a, b, c, d, e, f| self.write_to_c_conversion_inline_suffix_inner(a, b, c, d, e, f))
2678         }
2679         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 {
2680                 self.write_to_c_conversion_new_var_inner(w, ident, &format!("{}", ident), t, generics, ptr_for_ref, false)
2681         }
2682         /// Prints new-var conversion for an "ownable_ref" type, ie prints conversion for
2683         /// `create_ownable_reference(t)`, not `t` itself.
2684         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 {
2685                 self.write_to_c_conversion_new_var_inner(w, ident, &format!("{}", ident), t, generics, true, true)
2686         }
2687         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 {
2688                 self.write_conversion_new_var_intern(w, ident, &format!("{}", ident), t, generics, false, false, false, false,
2689                         &|a, b| self.from_c_conversion_new_var_from_path(a, b),
2690                         &|a, b, c, d, e| self.from_c_conversion_container_new_var(generics, a, b, c, d, e),
2691                         // We force ptr_for_ref here since we can't generate a ref on one line and use it later
2692                         &|a, b, c, d, e, _f| self.write_from_c_conversion_prefix_inner(a, b, c, d, e),
2693                         &|a, b, c, d, e, _f| self.write_from_c_conversion_suffix_inner(a, b, c, d, e))
2694         }
2695
2696         // ******************************************************
2697         // *** C Container Type Equivalent and alias Printing ***
2698         // ******************************************************
2699
2700         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 {
2701                 for (idx, orig_t) in args.enumerate() {
2702                         if idx != 0 {
2703                                 write!(w, ", ").unwrap();
2704                         }
2705                         let t = generics.resolve_type(orig_t);
2706                         if let syn::Type::Reference(r_arg) = t {
2707                                 assert!(!is_ref); // We don't currently support outer reference types for non-primitive inners
2708
2709                                 if !self.write_c_type_intern(w, &*r_arg.elem, generics, false, false, false, true, true) { return false; }
2710
2711                                 // While write_c_type_intern, above is correct, we don't want to blindly convert a
2712                                 // reference to something stupid, so check that the container is either opaque or a
2713                                 // predefined type (currently only Transaction).
2714                                 if let syn::Type::Path(p_arg) = &*r_arg.elem {
2715                                         let resolved = self.resolve_path(&p_arg.path, generics);
2716                                         assert!(self.crate_types.opaques.get(&resolved).is_some() ||
2717                                                         self.crate_types.traits.get(&resolved).is_some() ||
2718                                                         self.c_type_from_path(&resolved, true, true).is_some(), "Template generics should be opaque or have a predefined mapping");
2719                                 } else { unimplemented!(); }
2720                         } else if let syn::Type::Path(p_arg) = t {
2721                                 if let Some(resolved) = self.maybe_resolve_path(&p_arg.path, generics) {
2722                                         if !self.is_primitive(&resolved) && self.c_type_from_path(&resolved, false, false).is_none() {
2723                                                 if is_ref {
2724                                                         // We don't currently support outer reference types for non-primitive inners
2725                                                         return false;
2726                                                 }
2727                                         }
2728                                 } else {
2729                                         return false;
2730                                 }
2731                                 if !self.write_c_type_intern(w, t, generics, false, false, false, true, true) { return false; }
2732                         } else {
2733                                 // We don't currently support outer reference types for non-primitive inners,
2734                                 // except for the empty tuple.
2735                                 if let syn::Type::Tuple(t_arg) = t {
2736                                         assert!(t_arg.elems.len() == 0 || !is_ref);
2737                                 } else {
2738                                         assert!(!is_ref);
2739                                 }
2740                                 if !self.write_c_type_intern(w, t, generics, false, false, false, true, true) { return false; }
2741                         }
2742                 }
2743                 true
2744         }
2745         fn check_create_container(&self, mangled_container: String, container_type: &str, args: Vec<&syn::Type>, generics: Option<&GenericTypes>, is_ref: bool) -> bool {
2746                 if !self.crate_types.templates_defined.borrow().get(&mangled_container).is_some() {
2747                         let mut created_container: Vec<u8> = Vec::new();
2748
2749                         if container_type == "Result" {
2750                                 let mut a_ty: Vec<u8> = Vec::new();
2751                                 if let syn::Type::Tuple(tup) = args.iter().next().unwrap() {
2752                                         if tup.elems.is_empty() {
2753                                                 write!(&mut a_ty, "()").unwrap();
2754                                         } else {
2755                                                 if !self.write_template_generics(&mut a_ty, &mut args.iter().map(|t| *t).take(1), generics, is_ref) { return false; }
2756                                         }
2757                                 } else {
2758                                         if !self.write_template_generics(&mut a_ty, &mut args.iter().map(|t| *t).take(1), generics, is_ref) { return false; }
2759                                 }
2760
2761                                 let mut b_ty: Vec<u8> = Vec::new();
2762                                 if let syn::Type::Tuple(tup) = args.iter().skip(1).next().unwrap() {
2763                                         if tup.elems.is_empty() {
2764                                                 write!(&mut b_ty, "()").unwrap();
2765                                         } else {
2766                                                 if !self.write_template_generics(&mut b_ty, &mut args.iter().map(|t| *t).skip(1), generics, is_ref) { return false; }
2767                                         }
2768                                 } else {
2769                                         if !self.write_template_generics(&mut b_ty, &mut args.iter().map(|t| *t).skip(1), generics, is_ref) { return false; }
2770                                 }
2771
2772                                 let ok_str = String::from_utf8(a_ty).unwrap();
2773                                 let err_str = String::from_utf8(b_ty).unwrap();
2774                                 let is_clonable = self.is_clonable(&ok_str) && self.is_clonable(&err_str);
2775                                 write_result_block(&mut created_container, &mangled_container, &ok_str, &err_str, is_clonable);
2776                                 if is_clonable {
2777                                         self.crate_types.set_clonable(Self::generated_container_path().to_owned() + "::" + &mangled_container);
2778                                 }
2779                         } else if container_type == "Vec" {
2780                                 let mut a_ty: Vec<u8> = Vec::new();
2781                                 if !self.write_template_generics(&mut a_ty, &mut args.iter().map(|t| *t), generics, is_ref) { return false; }
2782                                 let ty = String::from_utf8(a_ty).unwrap();
2783                                 let is_clonable = self.is_clonable(&ty);
2784                                 write_vec_block(&mut created_container, &mangled_container, &ty, is_clonable);
2785                                 if is_clonable {
2786                                         self.crate_types.set_clonable(Self::generated_container_path().to_owned() + "::" + &mangled_container);
2787                                 }
2788                         } else if container_type.ends_with("Tuple") {
2789                                 let mut tuple_args = Vec::new();
2790                                 let mut is_clonable = true;
2791                                 for arg in args.iter() {
2792                                         let mut ty: Vec<u8> = Vec::new();
2793                                         if !self.write_template_generics(&mut ty, &mut [arg].iter().map(|t| **t), generics, is_ref) { return false; }
2794                                         let ty_str = String::from_utf8(ty).unwrap();
2795                                         if !self.is_clonable(&ty_str) {
2796                                                 is_clonable = false;
2797                                         }
2798                                         tuple_args.push(ty_str);
2799                                 }
2800                                 write_tuple_block(&mut created_container, &mangled_container, &tuple_args, is_clonable);
2801                                 if is_clonable {
2802                                         self.crate_types.set_clonable(Self::generated_container_path().to_owned() + "::" + &mangled_container);
2803                                 }
2804                         } else if container_type == "Option" {
2805                                 let mut a_ty: Vec<u8> = Vec::new();
2806                                 if !self.write_template_generics(&mut a_ty, &mut args.iter().map(|t| *t), generics, is_ref) { return false; }
2807                                 let ty = String::from_utf8(a_ty).unwrap();
2808                                 let is_clonable = self.is_clonable(&ty);
2809                                 write_option_block(&mut created_container, &mangled_container, &ty, is_clonable);
2810                                 if is_clonable {
2811                                         self.crate_types.set_clonable(Self::generated_container_path().to_owned() + "::" + &mangled_container);
2812                                 }
2813                         } else {
2814                                 unreachable!();
2815                         }
2816                         self.crate_types.write_new_template(mangled_container.clone(), true, &created_container);
2817                 }
2818                 true
2819         }
2820         fn path_to_generic_args(path: &syn::Path) -> Vec<&syn::Type> {
2821                 if let syn::PathArguments::AngleBracketed(args) = &path.segments.iter().next().unwrap().arguments {
2822                         args.args.iter().map(|gen| if let syn::GenericArgument::Type(t) = gen { t } else { unimplemented!() }).collect()
2823                 } else { unimplemented!(); }
2824         }
2825         fn write_c_mangled_container_path_intern<W: std::io::Write>
2826                         (&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 {
2827                 let mut mangled_type: Vec<u8> = Vec::new();
2828                 if !self.is_transparent_container(ident, is_ref, args.iter().map(|a| *a), generics) {
2829                         write!(w, "C{}_", ident).unwrap();
2830                         write!(mangled_type, "C{}_", ident).unwrap();
2831                 } else { assert_eq!(args.len(), 1); }
2832                 for arg in args.iter() {
2833                         macro_rules! write_path {
2834                                 ($p_arg: expr, $extra_write: expr) => {
2835                                         if let Some(subtype) = self.maybe_resolve_path(&$p_arg.path, generics) {
2836                                                 if self.is_transparent_container(ident, is_ref, args.iter().map(|a| *a), generics) {
2837                                                         if !in_type {
2838                                                                 if self.c_type_has_inner_from_path(&subtype) {
2839                                                                         if !self.write_c_path_intern(w, &$p_arg.path, generics, is_ref, is_mut, ptr_for_ref, false, true) { return false; }
2840                                                                 } else {
2841                                                                         // Option<T> needs to be converted to a *mut T, ie mut ptr-for-ref
2842                                                                         if !self.write_c_path_intern(w, &$p_arg.path, generics, true, true, true, false, true) { return false; }
2843                                                                 }
2844                                                         } else {
2845                                                                 write!(w, "{}", $p_arg.path.segments.last().unwrap().ident).unwrap();
2846                                                         }
2847                                                 } else if self.is_known_container(&subtype, is_ref) || self.is_path_transparent_container(&$p_arg.path, generics, is_ref) {
2848                                                         if !self.write_c_mangled_container_path_intern(w, Self::path_to_generic_args(&$p_arg.path), generics,
2849                                                                         &subtype, is_ref, is_mut, ptr_for_ref, true) {
2850                                                                 return false;
2851                                                         }
2852                                                         self.write_c_mangled_container_path_intern(&mut mangled_type, Self::path_to_generic_args(&$p_arg.path),
2853                                                                 generics, &subtype, is_ref, is_mut, ptr_for_ref, true);
2854                                                         if let Some(w2) = $extra_write as Option<&mut Vec<u8>> {
2855                                                                 self.write_c_mangled_container_path_intern(w2, Self::path_to_generic_args(&$p_arg.path),
2856                                                                         generics, &subtype, is_ref, is_mut, ptr_for_ref, true);
2857                                                         }
2858                                                 } else {
2859                                                         let id = subtype.rsplitn(2, ':').next().unwrap(); // Get the "Base" name of the resolved type
2860                                                         write!(w, "{}", id).unwrap();
2861                                                         write!(mangled_type, "{}", id).unwrap();
2862                                                         if let Some(w2) = $extra_write as Option<&mut Vec<u8>> {
2863                                                                 write!(w2, "{}", id).unwrap();
2864                                                         }
2865                                                 }
2866                                         } else { return false; }
2867                                 }
2868                         }
2869                         match generics.resolve_type(arg) {
2870                                 syn::Type::Tuple(tuple) => {
2871                                         if tuple.elems.len() == 0 {
2872                                                 write!(w, "None").unwrap();
2873                                                 write!(mangled_type, "None").unwrap();
2874                                         } else {
2875                                                 let mut mangled_tuple_type: Vec<u8> = Vec::new();
2876
2877                                                 // Figure out what the mangled type should look like. To disambiguate
2878                                                 // ((A, B), C) and (A, B, C) we prefix the generic args with a _ and suffix
2879                                                 // them with a Z. Ideally we wouldn't use Z, but not many special chars are
2880                                                 // available for use in type names.
2881                                                 write!(w, "C{}Tuple_", tuple.elems.len()).unwrap();
2882                                                 write!(mangled_type, "C{}Tuple_", tuple.elems.len()).unwrap();
2883                                                 write!(mangled_tuple_type, "C{}Tuple_", tuple.elems.len()).unwrap();
2884                                                 for elem in tuple.elems.iter() {
2885                                                         if let syn::Type::Path(p) = elem {
2886                                                                 write_path!(p, Some(&mut mangled_tuple_type));
2887                                                         } else if let syn::Type::Reference(refelem) = elem {
2888                                                                 if let syn::Type::Path(p) = &*refelem.elem {
2889                                                                         write_path!(p, Some(&mut mangled_tuple_type));
2890                                                                 } else { return false; }
2891                                                         } else if let syn::Type::Array(_) = elem {
2892                                                                 let mut resolved = Vec::new();
2893                                                                 if !self.write_c_type_intern(&mut resolved, &elem, generics, false, false, true, false, true) { return false; }
2894                                                                 let array_inner = String::from_utf8(resolved).unwrap();
2895                                                                 let arr_name = array_inner.split("::").last().unwrap();
2896                                                                 write!(w, "{}", arr_name).unwrap();
2897                                                                 write!(mangled_type, "{}", arr_name).unwrap();
2898                                                         } else { return false; }
2899                                                 }
2900                                                 write!(w, "Z").unwrap();
2901                                                 write!(mangled_type, "Z").unwrap();
2902                                                 write!(mangled_tuple_type, "Z").unwrap();
2903                                                 if !self.check_create_container(String::from_utf8(mangled_tuple_type).unwrap(),
2904                                                                 &format!("{}Tuple", tuple.elems.len()), tuple.elems.iter().collect(), generics, is_ref) {
2905                                                         return false;
2906                                                 }
2907                                         }
2908                                 },
2909                                 syn::Type::Path(p_arg) => {
2910                                         write_path!(p_arg, None);
2911                                 },
2912                                 syn::Type::Reference(refty) => {
2913                                         if let syn::Type::Path(p_arg) = &*refty.elem {
2914                                                 write_path!(p_arg, None);
2915                                         } else if let syn::Type::Slice(_) = &*refty.elem {
2916                                                 // write_c_type will actually do exactly what we want here, we just need to
2917                                                 // make it a pointer so that its an option. Note that we cannot always convert
2918                                                 // the Vec-as-slice (ie non-ref types) containers, so sometimes need to be able
2919                                                 // to edit it, hence we use *mut here instead of *const.
2920                                                 if args.len() != 1 { return false; }
2921                                                 write!(w, "*mut ").unwrap();
2922                                                 self.write_c_type(w, arg, None, true);
2923                                         } else { return false; }
2924                                 },
2925                                 syn::Type::Array(a) => {
2926                                         if let syn::Type::Path(p_arg) = &*a.elem {
2927                                                 let resolved = self.resolve_path(&p_arg.path, generics);
2928                                                 if !self.is_primitive(&resolved) { return false; }
2929                                                 if let syn::Expr::Lit(syn::ExprLit { lit: syn::Lit::Int(len), .. }) = &a.len {
2930                                                         if self.c_type_from_path(&format!("[{}; {}]", resolved, len.base10_digits()), is_ref, ptr_for_ref).is_none() { return false; }
2931                                                         if in_type || args.len() != 1 {
2932                                                                 write!(w, "_{}{}", resolved, len.base10_digits()).unwrap();
2933                                                                 write!(mangled_type, "_{}{}", resolved, len.base10_digits()).unwrap();
2934                                                         } else {
2935                                                                 let arrty = format!("[{}; {}]", resolved, len.base10_digits());
2936                                                                 let realty = self.c_type_from_path(&arrty, is_ref, ptr_for_ref).unwrap_or(&arrty);
2937                                                                 write!(w, "{}", realty).unwrap();
2938                                                                 write!(mangled_type, "{}", realty).unwrap();
2939                                                         }
2940                                                 } else { return false; }
2941                                         } else { return false; }
2942                                 },
2943                                 _ => { return false; },
2944                         }
2945                 }
2946                 if self.is_transparent_container(ident, is_ref, args.iter().map(|a| *a), generics) { return true; }
2947                 // Push the "end of type" Z
2948                 write!(w, "Z").unwrap();
2949                 write!(mangled_type, "Z").unwrap();
2950
2951                 // Make sure the type is actually defined:
2952                 self.check_create_container(String::from_utf8(mangled_type).unwrap(), ident, args, generics, is_ref)
2953         }
2954         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 {
2955                 if !self.is_transparent_container(ident, is_ref, args.iter().map(|a| *a), generics) {
2956                         write!(w, "{}::", Self::generated_container_path()).unwrap();
2957                 }
2958                 self.write_c_mangled_container_path_intern(w, args, generics, ident, is_ref, is_mut, ptr_for_ref, false)
2959         }
2960         pub fn get_c_mangled_container_type(&self, args: Vec<&syn::Type>, generics: Option<&GenericTypes>, template_name: &str) -> Option<String> {
2961                 let mut out = Vec::new();
2962                 if !self.write_c_mangled_container_path(&mut out, args, generics, template_name, false, false, false) {
2963                         return None;
2964                 }
2965                 Some(String::from_utf8(out).unwrap())
2966         }
2967
2968         // **********************************
2969         // *** C Type Equivalent Printing ***
2970         // **********************************
2971
2972         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 {
2973                 let full_path = match self.maybe_resolve_path(&path, generics) {
2974                         Some(path) => path, None => return false };
2975                 if let Some(c_type) = self.c_type_from_path(&full_path, is_ref, ptr_for_ref) {
2976                         write!(w, "{}", c_type).unwrap();
2977                         true
2978                 } else if self.crate_types.traits.get(&full_path).is_some() {
2979                         // Note that we always use the crate:: prefix here as we are always referring to a
2980                         // concrete object which is of the generated type, it just implements the upstream
2981                         // type.
2982                         if is_ref && ptr_for_ref {
2983                                 write!(w, "*{} crate::{}", if is_mut { "mut" } else { "const" }, full_path).unwrap();
2984                         } else if is_ref {
2985                                 if with_ref_lifetime { unimplemented!(); }
2986                                 write!(w, "&{}crate::{}", if is_mut { "mut " } else { "" }, full_path).unwrap();
2987                         } else {
2988                                 write!(w, "crate::{}", full_path).unwrap();
2989                         }
2990                         true
2991                 } else if self.crate_types.opaques.get(&full_path).is_some() || self.crate_types.mirrored_enums.get(&full_path).is_some() {
2992                         let crate_pfx = if c_ty { "crate::" } else { "" };
2993                         if is_ref && ptr_for_ref {
2994                                 // ptr_for_ref implies we're returning the object, which we can't really do for
2995                                 // opaque or mirrored types without box'ing them, which is quite a waste, so return
2996                                 // the actual object itself (for opaque types we'll set the pointer to the actual
2997                                 // type and note that its a reference).
2998                                 write!(w, "{}{}", crate_pfx, full_path).unwrap();
2999                         } else if is_ref && with_ref_lifetime {
3000                                 assert!(!is_mut);
3001                                 // If we're concretizing something with a lifetime parameter, we have to pick a
3002                                 // lifetime, of which the only real available choice is `static`, obviously.
3003                                 write!(w, "&'static {}", crate_pfx).unwrap();
3004                                 if !c_ty {
3005                                         self.write_rust_path(w, generics, path, with_ref_lifetime, false);
3006                                 } else {
3007                                         // We shouldn't be mapping references in types, so panic here
3008                                         unimplemented!();
3009                                 }
3010                         } else if is_ref {
3011                                 write!(w, "&{}{}{}", if is_mut { "mut " } else { "" }, crate_pfx, full_path).unwrap();
3012                         } else {
3013                                 write!(w, "{}{}", crate_pfx, full_path).unwrap();
3014                         }
3015                         true
3016                 } else {
3017                         if let Some(trait_impls) = self.crate_types.traits_impld.get(&full_path) {
3018                                 if trait_impls.len() == 1 {
3019                                         // If this is a no-export'd crate and there's only one implementation in the
3020                                         // whole crate, just treat it as a reference to whatever the implementor is.
3021                                         if with_ref_lifetime {
3022                                                 write!(w, "&'static crate::{}", trait_impls[0]).unwrap();
3023                                         } else {
3024                                                 write!(w, "&crate::{}", trait_impls[0]).unwrap();
3025                                         }
3026                                         return true;
3027                                 }
3028                         }
3029                         false
3030                 }
3031         }
3032         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 {
3033                 match generics.resolve_type(t) {
3034                         syn::Type::Path(p) => {
3035                                 if p.qself.is_some() {
3036                                         return false;
3037                                 }
3038                                 if let Some(full_path) = self.maybe_resolve_path(&p.path, generics) {
3039                                         if self.is_known_container(&full_path, is_ref) || self.is_path_transparent_container(&p.path, generics, is_ref) {
3040                                                 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);
3041                                         }
3042                                         if let Some(aliased_type) = self.crate_types.type_aliases.get(&full_path).cloned() {
3043                                                 return self.write_c_type_intern(w, &aliased_type, None, is_ref, is_mut, ptr_for_ref, with_ref_lifetime, c_ty);
3044                                         }
3045                                 }
3046                                 self.write_c_path_intern(w, &p.path, generics, is_ref, is_mut, ptr_for_ref, with_ref_lifetime, c_ty)
3047                         },
3048                         syn::Type::Reference(r) => {
3049                                 self.write_c_type_intern(w, &*r.elem, generics, true, r.mutability.is_some(), ptr_for_ref, with_ref_lifetime, c_ty)
3050                         },
3051                         syn::Type::Array(a) => {
3052                                 if is_ref && is_mut {
3053                                         write!(w, "*mut [").unwrap();
3054                                         if !self.write_c_type_intern(w, &a.elem, generics, false, false, ptr_for_ref, with_ref_lifetime, c_ty) { return false; }
3055                                 } else if is_ref {
3056                                         write!(w, "*const [").unwrap();
3057                                         if !self.write_c_type_intern(w, &a.elem, generics, false, false, ptr_for_ref, with_ref_lifetime, c_ty) { return false; }
3058                                 }
3059                                 if let syn::Expr::Lit(l) = &a.len {
3060                                         if let syn::Lit::Int(i) = &l.lit {
3061                                                 let mut inner_ty = Vec::new();
3062                                                 if !self.write_c_type_intern(&mut inner_ty, &*a.elem, generics, false, false, ptr_for_ref, false, c_ty) { return false; }
3063                                                 let inner_ty_str = String::from_utf8(inner_ty).unwrap();
3064                                                 if !is_ref {
3065                                                         if let Some(ty) = self.c_type_from_path(&format!("[{}; {}]", inner_ty_str, i.base10_digits()), false, ptr_for_ref) {
3066                                                                 write!(w, "{}", ty).unwrap();
3067                                                                 true
3068                                                         } else { false }
3069                                                 } else {
3070                                                         write!(w, "; {}]", i).unwrap();
3071                                                         true
3072                                                 }
3073                                         } else { false }
3074                                 } else { false }
3075                         }
3076                         syn::Type::Slice(s) => {
3077                                 if !is_ref || is_mut { return false; }
3078                                 if let syn::Type::Path(p) = &*s.elem {
3079                                         let resolved = self.resolve_path(&p.path, generics);
3080                                         if self.is_primitive(&resolved) {
3081                                                 write!(w, "{}::{}slice", Self::container_templ_path(), resolved).unwrap();
3082                                                 true
3083                                         } else {
3084                                                 let mut inner_c_ty = Vec::new();
3085                                                 assert!(self.write_c_path_intern(&mut inner_c_ty, &p.path, generics, true, false, ptr_for_ref, with_ref_lifetime, c_ty));
3086                                                 let inner_ty_str = String::from_utf8(inner_c_ty).unwrap();
3087                                                 if self.is_clonable(&inner_ty_str) {
3088                                                         let inner_ty_ident = inner_ty_str.rsplitn(2, "::").next().unwrap();
3089                                                         let mangled_container = format!("CVec_{}Z", inner_ty_ident);
3090                                                         write!(w, "{}::{}", Self::generated_container_path(), mangled_container).unwrap();
3091                                                         self.check_create_container(mangled_container, "Vec", vec![&*s.elem], generics, false)
3092                                                 } else { false }
3093                                         }
3094                                 } else if let syn::Type::Reference(r) = &*s.elem {
3095                                         if let syn::Type::Path(p) = &*r.elem {
3096                                                 // Slices with "real types" inside are mapped as the equivalent non-ref Vec
3097                                                 let resolved = self.resolve_path(&p.path, generics);
3098                                                 let mangled_container = if let Some((ident, _)) = self.crate_types.opaques.get(&resolved) {
3099                                                         format!("CVec_{}Z", ident)
3100                                                 } else if let Some(en) = self.crate_types.mirrored_enums.get(&resolved) {
3101                                                         format!("CVec_{}Z", en.ident)
3102                                                 } else if let Some(id) = p.path.get_ident() {
3103                                                         format!("CVec_{}Z", id)
3104                                                 } else { return false; };
3105                                                 write!(w, "{}::{}", Self::generated_container_path(), mangled_container).unwrap();
3106                                                 self.check_create_container(mangled_container, "Vec", vec![&*r.elem], generics, false)
3107                                         } else if let syn::Type::Slice(sl2) = &*r.elem {
3108                                                 if let syn::Type::Reference(r2) = &*sl2.elem {
3109                                                         if let syn::Type::Path(p) = &*r2.elem {
3110                                                                 // Slices with slices with opaque types (with is_owned flags) are mapped as non-ref Vecs
3111                                                                 let resolved = self.resolve_path(&p.path, generics);
3112                                                                 let mangled_container = if let Some((ident, _)) = self.crate_types.opaques.get(&resolved) {
3113                                                                         format!("CVec_CVec_{}ZZ", ident)
3114                                                                 } else { return false; };
3115                                                                 write!(w, "{}::{}", Self::generated_container_path(), mangled_container).unwrap();
3116                                                                 let inner = &r2.elem;
3117                                                                 let vec_ty: syn::Type = syn::parse_quote!(Vec<#inner>);
3118                                                                 self.check_create_container(mangled_container, "Vec", vec![&vec_ty], generics, false)
3119                                                         } else { false }
3120                                                 } else { false }
3121                                         } else { false }
3122                                 } else if let syn::Type::Tuple(_) = &*s.elem {
3123                                         let mut args = syn::punctuated::Punctuated::<_, syn::token::Comma>::new();
3124                                         args.push(syn::GenericArgument::Type((*s.elem).clone()));
3125                                         let mut segments = syn::punctuated::Punctuated::new();
3126                                         segments.push(parse_quote!(Vec<#args>));
3127                                         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)
3128                                 } else if let syn::Type::Array(a) = &*s.elem {
3129                                         if let syn::Expr::Lit(l) = &a.len {
3130                                                 if let syn::Lit::Int(i) = &l.lit {
3131                                                         let mut buf = Vec::new();
3132                                                         self.write_rust_type(&mut buf, generics, &*a.elem, false);
3133                                                         let arr_ty = String::from_utf8(buf).unwrap();
3134
3135                                                         let arr_str = format!("[{}; {}]", arr_ty, i.base10_digits());
3136                                                         let ty = self.c_type_from_path(&arr_str, false, ptr_for_ref).unwrap()
3137                                                                 .rsplitn(2, "::").next().unwrap();
3138
3139                                                         let mangled_container = format!("CVec_{}Z", ty);
3140                                                         write!(w, "{}::{}", Self::generated_container_path(), mangled_container).unwrap();
3141                                                         self.check_create_container(mangled_container, "Vec", vec![&*s.elem], generics, false)
3142                                                 } else { false }
3143                                         } else { false }
3144                                 } else { false }
3145                         },
3146                         syn::Type::Tuple(t) => {
3147                                 if t.elems.len() == 0 {
3148                                         true
3149                                 } else {
3150                                         self.write_c_mangled_container_path(w, t.elems.iter().collect(), generics,
3151                                                 &format!("{}Tuple", t.elems.len()), is_ref, is_mut, ptr_for_ref)
3152                                 }
3153                         },
3154                         _ => false,
3155                 }
3156         }
3157         pub fn write_c_type<W: std::io::Write>(&self, w: &mut W, t: &syn::Type, generics: Option<&GenericTypes>, ptr_for_ref: bool) {
3158                 assert!(self.write_c_type_intern(w, t, generics, false, false, ptr_for_ref, false, true));
3159         }
3160         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) {
3161                 assert!(self.write_c_type_intern(w, t, generics, false, false, ptr_for_ref, true, false));
3162         }
3163         pub fn understood_c_path(&self, p: &syn::Path) -> bool {
3164                 self.write_c_path_intern(&mut std::io::sink(), p, None, false, false, false, false, true)
3165         }
3166         pub fn understood_c_type(&self, t: &syn::Type, generics: Option<&GenericTypes>) -> bool {
3167                 self.write_c_type_intern(&mut std::io::sink(), t, generics, false, false, false, false, true)
3168         }
3169 }