_ 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
  19 // The following utils are used purely to build our known types maps - they break down all the
  20 // types we need to resolve to include the given object, and no more.
  21
  22 pub fn first_seg_self<'a>(t: &'a syn::Type) -> Option<impl Iterator<Item=&syn::PathSegment> + 'a> {
  23         match t {
  24                 syn::Type::Path(p) => {
  25                         if p.qself.is_some() || p.path.leading_colon.is_some() {
  26                                 return None;
  27                         }
  28                         let mut segs = p.path.segments.iter();
  29                         let ty = segs.next().unwrap();
  30                         if !ty.arguments.is_empty() { return None; }
  31                         if format!("{}", ty.ident) == "Self" {
  32                                 Some(segs)
  33                         } else { None }
  34                 },
  35                 _ => None,
  36         }
  37 }
  38
  39 pub fn get_single_remaining_path_seg<'a, I: Iterator<Item=&'a syn::PathSegment>>(segs: &mut I) -> Option<&'a syn::Ident> {
  40         if let Some(ty) = segs.next() {
  41                 if !ty.arguments.is_empty() { unimplemented!(); }
  42                 if segs.next().is_some() { return None; }
  43                 Some(&ty.ident)
  44         } else { None }
  45 }
  46
  47 pub fn single_ident_generic_path_to_ident(p: &syn::Path) -> Option<&syn::Ident> {
  48         if p.segments.len() == 1 {
  49                 Some(&p.segments.iter().next().unwrap().ident)
  50         } else { None }
  51 }
  52
  53 pub fn path_matches_nongeneric(p: &syn::Path, exp: &[&str]) -> bool {
  54         if p.segments.len() != exp.len() { return false; }
  55         for (seg, e) in p.segments.iter().zip(exp.iter()) {
  56                 if seg.arguments != syn::PathArguments::None { return false; }
  57                 if &format!("{}", seg.ident) != *e { return false; }
  58         }
  59         true
  60 }
  61
  62 #[derive(Debug, PartialEq)]
  63 pub enum ExportStatus {
  64         Export,
  65         NoExport,
  66         TestOnly,
  67 }
  68 /// Gets the ExportStatus of an object (struct, fn, etc) given its attributes.
  69 pub fn export_status(attrs: &[syn::Attribute]) -> ExportStatus {
  70         for attr in attrs.iter() {
  71                 let tokens_clone = attr.tokens.clone();
  72                 let mut token_iter = tokens_clone.into_iter();
  73                 if let Some(token) = token_iter.next() {
  74                         match token {
  75                                 TokenTree::Punct(c) if c.as_char() == '=' => {
  76                                         // Really not sure where syn gets '=' from here -
  77                                         // it somehow represents '///' or '//!'
  78                                 },
  79                                 TokenTree::Group(g) => {
  80                                         if format!("{}", single_ident_generic_path_to_ident(&attr.path).unwrap()) == "cfg" {
  81                                                 let mut iter = g.stream().into_iter();
  82                                                 if let TokenTree::Ident(i) = iter.next().unwrap() {
  83                                                         if i == "any" {
  84                                                                 // #[cfg(any(test, feature = ""))]
  85                                                                 if let TokenTree::Group(g) = iter.next().unwrap() {
  86                                                                         let mut all_test = true;
  87                                                                         for token in g.stream().into_iter() {
  88                                                                                 if let TokenTree::Ident(i) = token {
  89                                                                                         match format!("{}", i).as_str() {
  90                                                                                                 "test" => {},
  91                                                                                                 "feature" => {},
  92                                                                                                 _ => all_test = false,
  93                                                                                         }
  94                                                                                 } else if let TokenTree::Literal(lit) = token {
  95                                                                                         if format!("{}", lit) != "fuzztarget" {
  96                                                                                                 all_test = false;
  97                                                                                         }
  98                                                                                 }
  99                                                                         }
 100                                                                         if all_test { return ExportStatus::TestOnly; }
 101                                                                 }
 102                                                         } else if i == "test" || i == "feature" {
 103                                                                 // If its cfg(feature(...)) we assume its test-only
 104                                                                 return ExportStatus::TestOnly;
 105                                                         }
 106                                                 }
 107                                         }
 108                                         continue; // eg #[derive()]
 109                                 },
 110                                 _ => unimplemented!(),
 111                         }
 112                 } else { continue; }
 113                 match token_iter.next().unwrap() {
 114                         TokenTree::Literal(lit) => {
 115                                 let line = format!("{}", lit);
 116                                 if line.contains("(C-not exported)") {
 117                                         return ExportStatus::NoExport;
 118                                 }
 119                         },
 120                         _ => unimplemented!(),
 121                 }
 122         }
 123         ExportStatus::Export
 124 }
 125
 126 pub fn assert_simple_bound(bound: &syn::TraitBound) {
 127         if bound.paren_token.is_some() || bound.lifetimes.is_some() { unimplemented!(); }
 128         if let syn::TraitBoundModifier::Maybe(_) = bound.modifier { unimplemented!(); }
 129 }
 130
 131 /// Returns true if the enum will be mapped as an opaue (ie struct with a pointer to the underlying
 132 /// type), otherwise it is mapped into a transparent, C-compatible version of itself.
 133 pub fn is_enum_opaque(e: &syn::ItemEnum) -> bool {
 134         for var in e.variants.iter() {
 135                 if let syn::Fields::Named(fields) = &var.fields {
 136                         for field in fields.named.iter() {
 137                                 match export_status(&field.attrs) {
 138                                         ExportStatus::Export|ExportStatus::TestOnly => {},
 139                                         ExportStatus::NoExport => return true,
 140                                 }
 141                         }
 142                 } else if let syn::Fields::Unnamed(fields) = &var.fields {
 143                         for field in fields.unnamed.iter() {
 144                                 match export_status(&field.attrs) {
 145                                         ExportStatus::Export|ExportStatus::TestOnly => {},
 146                                         ExportStatus::NoExport => return true,
 147                                 }
 148                         }
 149                 }
 150         }
 151         false
 152 }
 153
 154 /// A stack of sets of generic resolutions.
 155 ///
 156 /// This tracks the template parameters for a function, struct, or trait, allowing resolution into
 157 /// a concrete type. By pushing a new context onto the stack, this can track a function's template
 158 /// parameters inside of a generic struct or trait.
 159 ///
 160 /// It maps both direct types as well as Deref<Target = X>, mapping them via the provided
 161 /// TypeResolver's resolve_path function (ie traits map to the concrete jump table, structs to the
 162 /// concrete C container struct, etc).
 163 #[must_use]
 164 pub struct GenericTypes<'a, 'b> {
 165         parent: Option<&'b GenericTypes<'b, 'b>>,
 166         typed_generics: HashMap<&'a syn::Ident, (String, Option<&'a syn::Path>)>,
 167 }
 168 impl<'a, 'p: 'a> GenericTypes<'a, 'p> {
 169         pub fn new() -> Self {
 170                 Self { parent: None, typed_generics: HashMap::new(), }
 171         }
 172
 173         /// push a new context onto the stack, allowing for a new set of generics to be learned which
 174         /// will override any lower contexts, but which will still fall back to resoltion via lower
 175         /// contexts.
 176         pub fn push_ctx<'c>(&'c self) -> GenericTypes<'a, 'c> {
 177                 GenericTypes { parent: Some(self), typed_generics: HashMap::new(), }
 178         }
 179
 180         /// Learn the generics in generics in the current context, given a TypeResolver.
 181         pub fn learn_generics<'b, 'c>(&mut self, generics: &'a syn::Generics, types: &'b TypeResolver<'a, 'c>) -> bool {
 182                 // First learn simple generics...
 183                 for generic in generics.params.iter() {
 184                         match generic {
 185                                 syn::GenericParam::Type(type_param) => {
 186                                         let mut non_lifetimes_processed = false;
 187                                         for bound in type_param.bounds.iter() {
 188                                                 if let syn::TypeParamBound::Trait(trait_bound) = bound {
 189                                                         if let Some(ident) = single_ident_generic_path_to_ident(&trait_bound.path) {
 190                                                                 match &format!("{}", ident) as &str { "Send" => continue, "Sync" => continue, _ => {} }
 191                                                         }
 192                                                         if path_matches_nongeneric(&trait_bound.path, &["core", "clone", "Clone"]) { continue; }
 193
 194                                                         assert_simple_bound(&trait_bound);
 195                                                         if let Some(mut path) = types.maybe_resolve_path(&trait_bound.path, None) {
 196                                                                 if types.skip_path(&path) { continue; }
 197                                                                 if path == "Sized" { continue; }
 198                                                                 if non_lifetimes_processed { return false; }
 199                                                                 non_lifetimes_processed = true;
 200                                                                 let new_ident = if path != "std::ops::Deref" {
 201                                                                         path = "crate::".to_string() + &path;
 202                                                                         Some(&trait_bound.path)
 203                                                                 } else { None };
 204                                                                 self.typed_generics.insert(&type_param.ident, (path, new_ident));
 205                                                         } else { return false; }
 206                                                 }
 207                                         }
 208                                 },
 209                                 _ => {},
 210                         }
 211                 }
 212                 // Then find generics where we are required to pass a Deref<Target=X> and pretend its just X.
 213                 if let Some(wh) = &generics.where_clause {
 214                         for pred in wh.predicates.iter() {
 215                                 if let syn::WherePredicate::Type(t) = pred {
 216                                         if let syn::Type::Path(p) = &t.bounded_ty {
 217                                                 if p.qself.is_some() { return false; }
 218                                                 if p.path.leading_colon.is_some() { return false; }
 219                                                 let mut p_iter = p.path.segments.iter();
 220                                                 if let Some(gen) = self.typed_generics.get_mut(&p_iter.next().unwrap().ident) {
 221                                                         if gen.0 != "std::ops::Deref" { return false; }
 222                                                         if &format!("{}", p_iter.next().unwrap().ident) != "Target" { return false; }
 223
 224                                                         let mut non_lifetimes_processed = false;
 225                                                         for bound in t.bounds.iter() {
 226                                                                 if let syn::TypeParamBound::Trait(trait_bound) = bound {
 227                                                                         if let Some(id) = trait_bound.path.get_ident() {
 228                                                                                 if format!("{}", id) == "Sized" { continue; }
 229                                                                         }
 230                                                                         if non_lifetimes_processed { return false; }
 231                                                                         non_lifetimes_processed = true;
 232                                                                         assert_simple_bound(&trait_bound);
 233                                                                         *gen = ("crate::".to_string() + &types.resolve_path(&trait_bound.path, None),
 234                                                                                 Some(&trait_bound.path));
 235                                                                 }
 236                                                         }
 237                                                 } else { return false; }
 238                                         } else { return false; }
 239                                 }
 240                         }
 241                 }
 242                 for (_, (_, ident)) in self.typed_generics.iter() {
 243                         if ident.is_none() { return false; }
 244                 }
 245                 true
 246         }
 247
 248         /// Learn the associated types from the trait in the current context.
 249         pub fn learn_associated_types<'b, 'c>(&mut self, t: &'a syn::ItemTrait, types: &'b TypeResolver<'a, 'c>) {
 250                 for item in t.items.iter() {
 251                         match item {
 252                                 &syn::TraitItem::Type(ref t) => {
 253                                         if t.default.is_some() || t.generics.lt_token.is_some() { unimplemented!(); }
 254                                         let mut bounds_iter = t.bounds.iter();
 255                                         match bounds_iter.next().unwrap() {
 256                                                 syn::TypeParamBound::Trait(tr) => {
 257                                                         assert_simple_bound(&tr);
 258                                                         if let Some(mut path) = types.maybe_resolve_path(&tr.path, None) {
 259                                                                 if types.skip_path(&path) { continue; }
 260                                                                 // In general we handle Deref<Target=X> as if it were just X (and
 261                                                                 // implement Deref<Target=Self> for relevant types). We don't
 262                                                                 // bother to implement it for associated types, however, so we just
 263                                                                 // ignore such bounds.
 264                                                                 let new_ident = if path != "std::ops::Deref" {
 265                                                                         path = "crate::".to_string() + &path;
 266                                                                         Some(&tr.path)
 267                                                                 } else { None };
 268                                                                 self.typed_generics.insert(&t.ident, (path, new_ident));
 269                                                         } else { unimplemented!(); }
 270                                                 },
 271                                                 _ => unimplemented!(),
 272                                         }
 273                                         if bounds_iter.next().is_some() { unimplemented!(); }
 274                                 },
 275                                 _ => {},
 276                         }
 277                 }
 278         }
 279
 280         /// Attempt to resolve an Ident as a generic parameter and return the full path.
 281         pub fn maybe_resolve_ident<'b>(&'b self, ident: &syn::Ident) -> Option<&'b String> {
 282                 if let Some(res) = self.typed_generics.get(ident).map(|(a, _)| a) {
 283                         return Some(res);
 284                 }
 285                 if let Some(parent) = self.parent {
 286                         parent.maybe_resolve_ident(ident)
 287                 } else {
 288                         None
 289                 }
 290         }
 291         /// Attempt to resolve a Path as a generic parameter and return the full path. as both a string
 292         /// and syn::Path.
 293         pub fn maybe_resolve_path<'b>(&'b self, path: &syn::Path) -> Option<(&'b String, &'a syn::Path)> {
 294                 if let Some(ident) = path.get_ident() {
 295                         if let Some(res) = self.typed_generics.get(ident).map(|(a, b)| (a, b.unwrap())) {
 296                                 return Some(res);
 297                         }
 298                 } else {
 299                         // Associated types are usually specified as "Self::Generic", so we check for that
 300                         // explicitly here.
 301                         let mut it = path.segments.iter();
 302                         if path.segments.len() == 2 && format!("{}", it.next().unwrap().ident) == "Self" {
 303                                 let ident = &it.next().unwrap().ident;
 304                                 if let Some(res) = self.typed_generics.get(ident).map(|(a, b)| (a, b.unwrap())) {
 305                                         return Some(res);
 306                                 }
 307                         }
 308                 }
 309                 if let Some(parent) = self.parent {
 310                         parent.maybe_resolve_path(path)
 311                 } else {
 312                         None
 313                 }
 314         }
 315 }
 316
 317 #[derive(Clone, PartialEq)]
 318 // The type of declaration and the object itself
 319 pub enum DeclType<'a> {
 320         MirroredEnum,
 321         Trait(&'a syn::ItemTrait),
 322         StructImported,
 323         StructIgnored,
 324         EnumIgnored,
 325 }
 326
 327 pub struct ImportResolver<'mod_lifetime, 'crate_lft: 'mod_lifetime> {
 328         crate_name: &'mod_lifetime str,
 329         dependencies: &'mod_lifetime HashSet<syn::Ident>,
 330         module_path: &'mod_lifetime str,
 331         imports: HashMap<syn::Ident, (String, syn::Path)>,
 332         declared: HashMap<syn::Ident, DeclType<'crate_lft>>,
 333         priv_modules: HashSet<syn::Ident>,
 334 }
 335 impl<'mod_lifetime, 'crate_lft: 'mod_lifetime> ImportResolver<'mod_lifetime, 'crate_lft> {
 336         fn process_use_intern(crate_name: &str, dependencies: &HashSet<syn::Ident>, imports: &mut HashMap<syn::Ident, (String, syn::Path)>,
 337                         u: &syn::UseTree, partial_path: &str, mut path: syn::punctuated::Punctuated<syn::PathSegment, syn::token::Colon2>) {
 338
 339                 let new_path;
 340                 macro_rules! push_path {
 341                         ($ident: expr, $path_suffix: expr) => {
 342                                 if partial_path == "" && !dependencies.contains(&$ident) {
 343                                         new_path = format!("{}::{}{}", crate_name, $ident, $path_suffix);
 344                                         path.push(syn::PathSegment { ident: syn::Ident::new(crate_name, Span::call_site()), arguments: syn::PathArguments::None });
 345                                 } else {
 346                                         new_path = format!("{}{}{}", partial_path, $ident, $path_suffix);
 347                                 }
 348                                 path.push(syn::PathSegment { ident: $ident.clone(), arguments: syn::PathArguments::None });
 349                         }
 350                 }
 351                 match u {
 352                         syn::UseTree::Path(p) => {
 353                                 push_path!(p.ident, "::");
 354                                 Self::process_use_intern(crate_name, dependencies, imports, &p.tree, &new_path, path);
 355                         },
 356                         syn::UseTree::Name(n) => {
 357                                 push_path!(n.ident, "");
 358                                 imports.insert(n.ident.clone(), (new_path, syn::Path { leading_colon: Some(syn::Token![::](Span::call_site())), segments: path }));
 359                         },
 360                         syn::UseTree::Group(g) => {
 361                                 for i in g.items.iter() {
 362                                         Self::process_use_intern(crate_name, dependencies, imports, i, partial_path, path.clone());
 363                                 }
 364                         },
 365                         syn::UseTree::Rename(r) => {
 366                                 push_path!(r.ident, "");
 367                                 imports.insert(r.rename.clone(), (new_path, syn::Path { leading_colon: Some(syn::Token![::](Span::call_site())), segments: path }));
 368                         },
 369                         syn::UseTree::Glob(_) => {
 370                                 eprintln!("Ignoring * use for {} - this may result in resolution failures", partial_path);
 371                         },
 372                 }
 373         }
 374
 375         fn process_use(crate_name: &str, dependencies: &HashSet<syn::Ident>, imports: &mut HashMap<syn::Ident, (String, syn::Path)>, u: &syn::ItemUse) {
 376                 if let syn::Visibility::Public(_) = u.vis {
 377                         // We actually only use these for #[cfg(fuzztarget)]
 378                         eprintln!("Ignoring pub(use) tree!");
 379                         return;
 380                 }
 381                 if u.leading_colon.is_some() { eprintln!("Ignoring leading-colon use!"); return; }
 382                 Self::process_use_intern(crate_name, dependencies, imports, &u.tree, "", syn::punctuated::Punctuated::new());
 383         }
 384
 385         fn insert_primitive(imports: &mut HashMap<syn::Ident, (String, syn::Path)>, id: &str) {
 386                 let ident = syn::Ident::new(id, Span::call_site());
 387                 let mut path = syn::punctuated::Punctuated::new();
 388                 path.push(syn::PathSegment { ident: ident.clone(), arguments: syn::PathArguments::None });
 389                 imports.insert(ident, (id.to_owned(), syn::Path { leading_colon: None, segments: path }));
 390         }
 391
 392         pub fn new(crate_name: &'mod_lifetime str, dependencies: &'mod_lifetime HashSet<syn::Ident>, module_path: &'mod_lifetime str, contents: &'crate_lft [syn::Item]) -> Self {
 393                 let mut imports = HashMap::new();
 394                 // Add primitives to the "imports" list:
 395                 Self::insert_primitive(&mut imports, "bool");
 396                 Self::insert_primitive(&mut imports, "u64");
 397                 Self::insert_primitive(&mut imports, "u32");
 398                 Self::insert_primitive(&mut imports, "u16");
 399                 Self::insert_primitive(&mut imports, "u8");
 400                 Self::insert_primitive(&mut imports, "usize");
 401                 Self::insert_primitive(&mut imports, "str");
 402                 Self::insert_primitive(&mut imports, "String");
 403
 404                 // These are here to allow us to print native Rust types in trait fn impls even if we don't
 405                 // have C mappings:
 406                 Self::insert_primitive(&mut imports, "Result");
 407                 Self::insert_primitive(&mut imports, "Vec");
 408                 Self::insert_primitive(&mut imports, "Option");
 409
 410                 let mut declared = HashMap::new();
 411                 let mut priv_modules = HashSet::new();
 412
 413                 for item in contents.iter() {
 414                         match item {
 415                                 syn::Item::Use(u) => Self::process_use(crate_name, dependencies, &mut imports, &u),
 416                                 syn::Item::Struct(s) => {
 417                                         if let syn::Visibility::Public(_) = s.vis {
 418                                                 match export_status(&s.attrs) {
 419                                                         ExportStatus::Export => { declared.insert(s.ident.clone(), DeclType::StructImported); },
 420                                                         ExportStatus::NoExport => { declared.insert(s.ident.clone(), DeclType::StructIgnored); },
 421                                                         ExportStatus::TestOnly => continue,
 422                                                 }
 423                                         }
 424                                 },
 425                                 syn::Item::Type(t) if export_status(&t.attrs) == ExportStatus::Export => {
 426                                         if let syn::Visibility::Public(_) = t.vis {
 427                                                 let mut process_alias = true;
 428                                                 for tok in t.generics.params.iter() {
 429                                                         if let syn::GenericParam::Lifetime(_) = tok {}
 430                                                         else { process_alias = false; }
 431                                                 }
 432                                                 if process_alias {
 433                                                         declared.insert(t.ident.clone(), DeclType::StructImported);
 434                                                 }
 435                                         }
 436                                 },
 437                                 syn::Item::Enum(e) => {
 438                                         if let syn::Visibility::Public(_) = e.vis {
 439                                                 match export_status(&e.attrs) {
 440                                                         ExportStatus::Export if is_enum_opaque(e) => { declared.insert(e.ident.clone(), DeclType::EnumIgnored); },
 441                                                         ExportStatus::Export => { declared.insert(e.ident.clone(), DeclType::MirroredEnum); },
 442                                                         _ => continue,
 443                                                 }
 444                                         }
 445                                 },
 446                                 syn::Item::Trait(t) if export_status(&t.attrs) == ExportStatus::Export => {
 447                                         if let syn::Visibility::Public(_) = t.vis {
 448                                                 declared.insert(t.ident.clone(), DeclType::Trait(t));
 449                                         }
 450                                 },
 451                                 syn::Item::Mod(m) => {
 452                                         priv_modules.insert(m.ident.clone());
 453                                 },
 454                                 _ => {},
 455                         }
 456                 }
 457
 458                 Self { crate_name, dependencies, module_path, imports, declared, priv_modules }
 459         }
 460
 461         pub fn get_declared_type(&self, ident: &syn::Ident) -> Option<&DeclType<'crate_lft>> {
 462                 self.declared.get(ident)
 463         }
 464
 465         pub fn maybe_resolve_declared(&self, id: &syn::Ident) -> Option<&DeclType<'crate_lft>> {
 466                 self.declared.get(id)
 467         }
 468
 469         pub fn maybe_resolve_ident(&self, id: &syn::Ident) -> Option<String> {
 470                 if let Some((imp, _)) = self.imports.get(id) {
 471                         Some(imp.clone())
 472                 } else if self.declared.get(id).is_some() {
 473                         Some(self.module_path.to_string() + "::" + &format!("{}", id))
 474                 } else { None }
 475         }
 476
 477         pub fn maybe_resolve_non_ignored_ident(&self, id: &syn::Ident) -> Option<String> {
 478                 if let Some((imp, _)) = self.imports.get(id) {
 479                         Some(imp.clone())
 480                 } else if let Some(decl_type) = self.declared.get(id) {
 481                         match decl_type {
 482                                 DeclType::StructIgnored => None,
 483                                 _ => Some(self.module_path.to_string() + "::" + &format!("{}", id)),
 484                         }
 485                 } else { None }
 486         }
 487
 488         pub fn maybe_resolve_path(&self, p_arg: &syn::Path, generics: Option<&GenericTypes>) -> Option<String> {
 489                 let p = if let Some(gen_types) = generics {
 490                         if let Some((_, synpath)) = gen_types.maybe_resolve_path(p_arg) {
 491                                 synpath
 492                         } else { p_arg }
 493                 } else { p_arg };
 494
 495                 if p.leading_colon.is_some() {
 496                         let mut res: String = p.segments.iter().enumerate().map(|(idx, seg)| {
 497                                 format!("{}{}", if idx == 0 { "" } else { "::" }, seg.ident)
 498                         }).collect();
 499                         let firstseg = p.segments.iter().next().unwrap();
 500                         if !self.dependencies.contains(&firstseg.ident) {
 501                                 res = self.crate_name.to_owned() + "::" + &res;
 502                         }
 503                         Some(res)
 504                 } else if let Some(id) = p.get_ident() {
 505                         self.maybe_resolve_ident(id)
 506                 } else {
 507                         if p.segments.len() == 1 {
 508                                 let seg = p.segments.iter().next().unwrap();
 509                                 return self.maybe_resolve_ident(&seg.ident);
 510                         }
 511                         let mut seg_iter = p.segments.iter();
 512                         let first_seg = seg_iter.next().unwrap();
 513                         let remaining: String = seg_iter.map(|seg| {
 514                                 format!("::{}", seg.ident)
 515                         }).collect();
 516                         let first_seg_str = format!("{}", first_seg.ident);
 517                         if first_seg_str == "std" {
 518                                 Some(first_seg_str + &remaining)
 519                         } else if let Some((imp, _)) = self.imports.get(&first_seg.ident) {
 520                                 if remaining != "" {
 521                                         Some(imp.clone() + &remaining)
 522                                 } else {
 523                                         Some(imp.clone())
 524                                 }
 525                         } else if let Some(_) = self.priv_modules.get(&first_seg.ident) {
 526                                 Some(format!("{}::{}{}", self.module_path, first_seg.ident, remaining))
 527                         } else { None }
 528                 }
 529         }
 530
 531         /// Map all the Paths in a Type into absolute paths given a set of imports (generated via process_use_intern)
 532         pub fn resolve_imported_refs(&self, mut ty: syn::Type) -> syn::Type {
 533                 match &mut ty {
 534                         syn::Type::Path(p) => {
 535 eprintln!("rir {:?}", p);
 536                                 if p.path.segments.len() != 1 { unimplemented!(); }
 537                                 let mut args = p.path.segments[0].arguments.clone();
 538                                 if let syn::PathArguments::AngleBracketed(ref mut generics) = &mut args {
 539                                         for arg in generics.args.iter_mut() {
 540                                                 if let syn::GenericArgument::Type(ref mut t) = arg {
 541                                                         *t = self.resolve_imported_refs(t.clone());
 542                                                 }
 543                                         }
 544                                 }
 545                                 if let Some((_, newpath)) = self.imports.get(single_ident_generic_path_to_ident(&p.path).unwrap()) {
 546                                         p.path = newpath.clone();
 547                                 }
 548                                 p.path.segments[0].arguments = args;
 549                         },
 550                         syn::Type::Reference(r) => {
 551                                 r.elem = Box::new(self.resolve_imported_refs((*r.elem).clone()));
 552                         },
 553                         syn::Type::Slice(s) => {
 554                                 s.elem = Box::new(self.resolve_imported_refs((*s.elem).clone()));
 555                         },
 556                         syn::Type::Tuple(t) => {
 557                                 for e in t.elems.iter_mut() {
 558                                         *e = self.resolve_imported_refs(e.clone());
 559                                 }
 560                         },
 561                         _ => unimplemented!(),
 562                 }
 563                 ty
 564         }
 565 }
 566
 567 // templates_defined is walked to write the C++ header, so if we use the default hashing it get
 568 // reordered on each genbindings run. Instead, we use SipHasher (which defaults to 0-keys) so that
 569 // the sorting is stable across runs. It is deprecated, but the "replacement" doesn't actually
 570 // accomplish the same goals, so we just ignore it.
 571 #[allow(deprecated)]
 572 pub type NonRandomHash = hash::BuildHasherDefault<hash::SipHasher>;
 573
 574 /// A public module
 575 pub struct ASTModule {
 576         pub attrs: Vec<syn::Attribute>,
 577         pub items: Vec<syn::Item>,
 578         pub submods: Vec<String>,
 579 }
 580 /// A struct containing the syn::File AST for each file in the crate.
 581 pub struct FullLibraryAST {
 582         pub modules: HashMap<String, ASTModule, NonRandomHash>,
 583         pub dependencies: HashSet<syn::Ident>,
 584 }
 585 impl FullLibraryAST {
 586         fn load_module(&mut self, module: String, attrs: Vec<syn::Attribute>, mut items: Vec<syn::Item>) {
 587                 let mut non_mod_items = Vec::with_capacity(items.len());
 588                 let mut submods = Vec::with_capacity(items.len());
 589                 for item in items.drain(..) {
 590                         match item {
 591                                 syn::Item::Mod(m) if m.content.is_some() => {
 592                                         if export_status(&m.attrs) == ExportStatus::Export {
 593                                                 if let syn::Visibility::Public(_) = m.vis {
 594                                                         let modident = format!("{}", m.ident);
 595                                                         let modname = if module != "" {
 596                                                                 module.clone() + "::" + &modident
 597                                                         } else {
 598                                                                 modident.clone()
 599                                                         };
 600                                                         self.load_module(modname, m.attrs, m.content.unwrap().1);
 601                                                         submods.push(modident);
 602                                                 } else {
 603                                                         non_mod_items.push(syn::Item::Mod(m));
 604                                                 }
 605                                         }
 606                                 },
 607                                 syn::Item::Mod(_) => panic!("--pretty=expanded output should never have non-body modules"),
 608                                 syn::Item::ExternCrate(c) => {
 609                                         if export_status(&c.attrs) == ExportStatus::Export {
 610                                                 self.dependencies.insert(c.ident);
 611                                         }
 612                                 },
 613                                 _ => { non_mod_items.push(item); }
 614                         }
 615                 }
 616                 self.modules.insert(module, ASTModule { attrs, items: non_mod_items, submods });
 617         }
 618
 619         pub fn load_lib(lib: syn::File) -> Self {
 620                 assert_eq!(export_status(&lib.attrs), ExportStatus::Export);
 621                 let mut res = Self { modules: HashMap::default(), dependencies: HashSet::new() };
 622                 res.load_module("".to_owned(), lib.attrs, lib.items);
 623                 res
 624         }
 625 }
 626
 627 /// Top-level struct tracking everything which has been defined while walking the crate.
 628 pub struct CrateTypes<'a> {
 629         /// This may contain structs or enums, but only when either is mapped as
 630         /// struct X { inner: *mut originalX, .. }
 631         pub opaques: HashMap<String, &'a syn::Ident>,
 632         /// Enums which are mapped as C enums with conversion functions
 633         pub mirrored_enums: HashMap<String, &'a syn::ItemEnum>,
 634         /// Traits which are mapped as a pointer + jump table
 635         pub traits: HashMap<String, &'a syn::ItemTrait>,
 636         /// Aliases from paths to some other Type
 637         pub type_aliases: HashMap<String, syn::Type>,
 638         /// Value is an alias to Key (maybe with some generics)
 639         pub reverse_alias_map: HashMap<String, Vec<(syn::Path, syn::PathArguments)>>,
 640         /// Template continer types defined, map from mangled type name -> whether a destructor fn
 641         /// exists.
 642         ///
 643         /// This is used at the end of processing to make C++ wrapper classes
 644         pub templates_defined: RefCell<HashMap<String, bool, NonRandomHash>>,
 645         /// The output file for any created template container types, written to as we find new
 646         /// template containers which need to be defined.
 647         template_file: RefCell<&'a mut File>,
 648         /// Set of containers which are clonable
 649         clonable_types: RefCell<HashSet<String>>,
 650         /// Key impls Value
 651         pub trait_impls: HashMap<String, Vec<String>>,
 652         /// The full set of modules in the crate(s)
 653         pub lib_ast: &'a FullLibraryAST,
 654 }
 655
 656 impl<'a> CrateTypes<'a> {
 657         pub fn new(template_file: &'a mut File, libast: &'a FullLibraryAST) -> Self {
 658                 CrateTypes {
 659                         opaques: HashMap::new(), mirrored_enums: HashMap::new(), traits: HashMap::new(),
 660                         type_aliases: HashMap::new(), reverse_alias_map: HashMap::new(),
 661                         templates_defined: RefCell::new(HashMap::default()),
 662                         clonable_types: RefCell::new(HashSet::new()), trait_impls: HashMap::new(),
 663                         template_file: RefCell::new(template_file), lib_ast: &libast,
 664                 }
 665         }
 666         pub fn set_clonable(&self, object: String) {
 667                 self.clonable_types.borrow_mut().insert(object);
 668         }
 669         pub fn is_clonable(&self, object: &str) -> bool {
 670                 self.clonable_types.borrow().contains(object)
 671         }
 672         pub fn write_new_template(&self, mangled_container: String, has_destructor: bool, created_container: &[u8]) {
 673                 self.template_file.borrow_mut().write(created_container).unwrap();
 674                 self.templates_defined.borrow_mut().insert(mangled_container, has_destructor);
 675         }
 676 }
 677
 678 /// A struct which tracks resolving rust types into C-mapped equivalents, exists for one specific
 679 /// module but contains a reference to the overall CrateTypes tracking.
 680 pub struct TypeResolver<'mod_lifetime, 'crate_lft: 'mod_lifetime> {
 681         pub module_path: &'mod_lifetime str,
 682         pub crate_types: &'mod_lifetime CrateTypes<'crate_lft>,
 683         types: ImportResolver<'mod_lifetime, 'crate_lft>,
 684 }
 685
 686 /// Returned by write_empty_rust_val_check_suffix to indicate what type of dereferencing needs to
 687 /// happen to get the inner value of a generic.
 688 enum EmptyValExpectedTy {
 689         /// A type which has a flag for being empty (eg an array where we treat all-0s as empty).
 690         NonPointer,
 691         /// A pointer that we want to dereference and move out of.
 692         OwnedPointer,
 693         /// A pointer which we want to convert to a reference.
 694         ReferenceAsPointer,
 695 }
 696
 697 #[derive(PartialEq)]
 698 /// Describes the appropriate place to print a general type-conversion string when converting a
 699 /// container.
 700 enum ContainerPrefixLocation {
 701         /// Prints a general type-conversion string prefix and suffix outside of the
 702         /// container-conversion strings.
 703         OutsideConv,
 704         /// Prints a general type-conversion string prefix and suffix inside of the
 705         /// container-conversion strings.
 706         PerConv,
 707         /// Does not print the usual type-conversion string prefix and suffix.
 708         NoPrefix,
 709 }
 710
 711 impl<'a, 'c: 'a> TypeResolver<'a, 'c> {
 712         pub fn new(module_path: &'a str, types: ImportResolver<'a, 'c>, crate_types: &'a CrateTypes<'c>) -> Self {
 713                 Self { module_path, types, crate_types }
 714         }
 715
 716         // *************************************************
 717         // *** Well know type and conversion definitions ***
 718         // *************************************************
 719
 720         /// Returns true we if can just skip passing this to C entirely
 721         fn skip_path(&self, full_path: &str) -> bool {
 722                 full_path == "bitcoin::secp256k1::Secp256k1" ||
 723                 full_path == "bitcoin::secp256k1::Signing" ||
 724                 full_path == "bitcoin::secp256k1::Verification"
 725         }
 726         /// Returns true we if can just skip passing this to C entirely
 727         fn no_arg_path_to_rust(&self, full_path: &str) -> &str {
 728                 if full_path == "bitcoin::secp256k1::Secp256k1" {
 729                         "secp256k1::SECP256K1"
 730                 } else { unimplemented!(); }
 731         }
 732
 733         /// Returns true if the object is a primitive and is mapped as-is with no conversion
 734         /// whatsoever.
 735         pub fn is_primitive(&self, full_path: &str) -> bool {
 736                 match full_path {
 737                         "bool" => true,
 738                         "u64" => true,
 739                         "u32" => true,
 740                         "u16" => true,
 741                         "u8" => true,
 742                         "usize" => true,
 743                         _ => false,
 744                 }
 745         }
 746         pub fn is_clonable(&self, ty: &str) -> bool {
 747                 if self.crate_types.is_clonable(ty) { return true; }
 748                 if self.is_primitive(ty) { return true; }
 749                 match ty {
 750                         "()" => true,
 751                         "crate::c_types::Signature" => true,
 752                         "crate::c_types::TxOut" => true,
 753                         _ => false,
 754                 }
 755         }
 756         /// Gets the C-mapped type for types which are outside of the crate, or which are manually
 757         /// ignored by for some reason need mapping anyway.
 758         fn c_type_from_path<'b>(&self, full_path: &'b str, is_ref: bool, _ptr_for_ref: bool) -> Option<&'b str> {
 759                 if self.is_primitive(full_path) {
 760                         return Some(full_path);
 761                 }
 762                 match full_path {
 763                         "Result" => Some("crate::c_types::derived::CResult"),
 764                         "Vec" if !is_ref => Some("crate::c_types::derived::CVec"),
 765                         "Option" => Some(""),
 766
 767                         // Note that no !is_ref types can map to an array because Rust and C's call semantics
 768                         // for arrays are different (https://github.com/eqrion/cbindgen/issues/528)
 769
 770                         "[u8; 32]" if !is_ref => Some("crate::c_types::ThirtyTwoBytes"),
 771                         "[u8; 16]" if !is_ref => Some("crate::c_types::SixteenBytes"),
 772                         "[u8; 10]" if !is_ref => Some("crate::c_types::TenBytes"),
 773                         "[u8; 4]" if !is_ref => Some("crate::c_types::FourBytes"),
 774                         "[u8; 3]" if !is_ref => Some("crate::c_types::ThreeBytes"), // Used for RGB values
 775
 776                         "str" if is_ref => Some("crate::c_types::Str"),
 777                         "String" if !is_ref => Some("crate::c_types::derived::CVec_u8Z"),
 778                         "String" if is_ref => Some("crate::c_types::Str"),
 779
 780                         "std::time::Duration" => Some("u64"),
 781                         "std::io::Error" => Some("crate::c_types::IOError"),
 782
 783                         "bitcoin::secp256k1::key::PublicKey" => Some("crate::c_types::PublicKey"),
 784                         "bitcoin::secp256k1::Signature" => Some("crate::c_types::Signature"),
 785                         "bitcoin::secp256k1::key::SecretKey" if is_ref  => Some("*const [u8; 32]"),
 786                         "bitcoin::secp256k1::key::SecretKey" if !is_ref => Some("crate::c_types::SecretKey"),
 787                         "bitcoin::secp256k1::Error" if !is_ref => Some("crate::c_types::Secp256k1Error"),
 788                         "bitcoin::blockdata::script::Script" if is_ref => Some("crate::c_types::u8slice"),
 789                         "bitcoin::blockdata::script::Script" if !is_ref => Some("crate::c_types::derived::CVec_u8Z"),
 790                         "bitcoin::blockdata::transaction::OutPoint" => Some("crate::lightning::chain::transaction::OutPoint"),
 791                         "bitcoin::blockdata::transaction::Transaction" => Some("crate::c_types::Transaction"),
 792                         "bitcoin::blockdata::transaction::TxOut" if !is_ref => Some("crate::c_types::TxOut"),
 793                         "bitcoin::network::constants::Network" => Some("crate::bitcoin::network::Network"),
 794                         "bitcoin::blockdata::block::BlockHeader" if is_ref  => Some("*const [u8; 80]"),
 795                         "bitcoin::blockdata::block::Block" if is_ref  => Some("crate::c_types::u8slice"),
 796
 797                         // Newtypes that we just expose in their original form.
 798                         "bitcoin::hash_types::Txid" if is_ref  => Some("*const [u8; 32]"),
 799                         "bitcoin::hash_types::Txid" if !is_ref => Some("crate::c_types::ThirtyTwoBytes"),
 800                         "bitcoin::hash_types::BlockHash" if is_ref  => Some("*const [u8; 32]"),
 801                         "bitcoin::hash_types::BlockHash" if !is_ref => Some("crate::c_types::ThirtyTwoBytes"),
 802                         "bitcoin::secp256k1::Message" if !is_ref => Some("crate::c_types::ThirtyTwoBytes"),
 803                         "lightning::ln::channelmanager::PaymentHash" if is_ref => Some("*const [u8; 32]"),
 804                         "lightning::ln::channelmanager::PaymentHash" if !is_ref => Some("crate::c_types::ThirtyTwoBytes"),
 805                         "lightning::ln::channelmanager::PaymentPreimage" if is_ref => Some("*const [u8; 32]"),
 806                         "lightning::ln::channelmanager::PaymentPreimage" if !is_ref => Some("crate::c_types::ThirtyTwoBytes"),
 807                         "lightning::ln::channelmanager::PaymentSecret" if is_ref => Some("crate::c_types::ThirtyTwoBytes"),
 808                         "lightning::ln::channelmanager::PaymentSecret" if !is_ref => Some("crate::c_types::ThirtyTwoBytes"),
 809
 810                         // Override the default since Records contain an fmt with a lifetime:
 811                         "lightning::util::logger::Record" => Some("*const std::os::raw::c_char"),
 812
 813                         _ => None,
 814                 }
 815         }
 816
 817         fn from_c_conversion_new_var_from_path<'b>(&self, _full_path: &str, _is_ref: bool) -> Option<(&'b str, &'b str)> {
 818                 None
 819         }
 820         fn from_c_conversion_prefix_from_path<'b>(&self, full_path: &str, is_ref: bool) -> Option<String> {
 821                 if self.is_primitive(full_path) {
 822                         return Some("".to_owned());
 823                 }
 824                 match full_path {
 825                         "Vec" if !is_ref => Some("local_"),
 826                         "Result" if !is_ref => Some("local_"),
 827                         "Option" if is_ref => Some("&local_"),
 828                         "Option" => Some("local_"),
 829
 830                         "[u8; 32]" if is_ref => Some("unsafe { &*"),
 831                         "[u8; 32]" if !is_ref => Some(""),
 832                         "[u8; 16]" if !is_ref => Some(""),
 833                         "[u8; 10]" if !is_ref => Some(""),
 834                         "[u8; 4]" if !is_ref => Some(""),
 835                         "[u8; 3]" if !is_ref => Some(""),
 836
 837                         "[u8]" if is_ref => Some(""),
 838                         "[usize]" if is_ref => Some(""),
 839
 840                         "str" if is_ref => Some(""),
 841                         "String" if !is_ref => Some("String::from_utf8("),
 842                         // Note that we'll panic for String if is_ref, as we only have non-owned memory, we
 843                         // cannot create a &String.
 844
 845                         "std::time::Duration" => Some("std::time::Duration::from_secs("),
 846
 847                         "bitcoin::secp256k1::key::PublicKey" if is_ref => Some("&"),
 848                         "bitcoin::secp256k1::key::PublicKey" => Some(""),
 849                         "bitcoin::secp256k1::Signature" if is_ref => Some("&"),
 850                         "bitcoin::secp256k1::Signature" => Some(""),
 851                         "bitcoin::secp256k1::key::SecretKey" if is_ref => Some("&::bitcoin::secp256k1::key::SecretKey::from_slice(&unsafe { *"),
 852                         "bitcoin::secp256k1::key::SecretKey" if !is_ref => Some(""),
 853                         "bitcoin::blockdata::script::Script" if is_ref => Some("&::bitcoin::blockdata::script::Script::from(Vec::from("),
 854                         "bitcoin::blockdata::script::Script" if !is_ref => Some("::bitcoin::blockdata::script::Script::from("),
 855                         "bitcoin::blockdata::transaction::Transaction" if is_ref => Some("&"),
 856                         "bitcoin::blockdata::transaction::Transaction" => Some(""),
 857                         "bitcoin::blockdata::transaction::TxOut" if !is_ref => Some(""),
 858                         "bitcoin::network::constants::Network" => Some(""),
 859                         "bitcoin::blockdata::block::BlockHeader" => Some("&::bitcoin::consensus::encode::deserialize(unsafe { &*"),
 860                         "bitcoin::blockdata::block::Block" if is_ref => Some("&::bitcoin::consensus::encode::deserialize("),
 861
 862                         // Newtypes that we just expose in their original form.
 863                         "bitcoin::hash_types::Txid" if is_ref => Some("&::bitcoin::hash_types::Txid::from_slice(&unsafe { &*"),
 864                         "bitcoin::hash_types::Txid" if !is_ref => Some("::bitcoin::hash_types::Txid::from_slice(&"),
 865                         "bitcoin::hash_types::BlockHash" => Some("::bitcoin::hash_types::BlockHash::from_slice(&"),
 866                         "lightning::ln::channelmanager::PaymentHash" if !is_ref => Some("::lightning::ln::channelmanager::PaymentHash("),
 867                         "lightning::ln::channelmanager::PaymentHash" if is_ref => Some("&::lightning::ln::channelmanager::PaymentHash(unsafe { *"),
 868                         "lightning::ln::channelmanager::PaymentPreimage" if !is_ref => Some("::lightning::ln::channelmanager::PaymentPreimage("),
 869                         "lightning::ln::channelmanager::PaymentPreimage" if is_ref => Some("&::lightning::ln::channelmanager::PaymentPreimage(unsafe { *"),
 870                         "lightning::ln::channelmanager::PaymentSecret" => Some("::lightning::ln::channelmanager::PaymentSecret("),
 871
 872                         // List of traits we map (possibly during processing of other files):
 873                         "crate::util::logger::Logger" => Some(""),
 874
 875                         _ => None,
 876                 }.map(|s| s.to_owned())
 877         }
 878         fn from_c_conversion_suffix_from_path<'b>(&self, full_path: &str, is_ref: bool) -> Option<String> {
 879                 if self.is_primitive(full_path) {
 880                         return Some("".to_owned());
 881                 }
 882                 match full_path {
 883                         "Vec" if !is_ref => Some(""),
 884                         "Option" => Some(""),
 885                         "Result" if !is_ref => Some(""),
 886
 887                         "[u8; 32]" if is_ref => Some("}"),
 888                         "[u8; 32]" if !is_ref => Some(".data"),
 889                         "[u8; 16]" if !is_ref => Some(".data"),
 890                         "[u8; 10]" if !is_ref => Some(".data"),
 891                         "[u8; 4]" if !is_ref => Some(".data"),
 892                         "[u8; 3]" if !is_ref => Some(".data"),
 893
 894                         "[u8]" if is_ref => Some(".to_slice()"),
 895                         "[usize]" if is_ref => Some(".to_slice()"),
 896
 897                         "str" if is_ref => Some(".into()"),
 898                         "String" if !is_ref => Some(".into_rust()).unwrap()"),
 899
 900                         "std::time::Duration" => Some(")"),
 901
 902                         "bitcoin::secp256k1::key::PublicKey" => Some(".into_rust()"),
 903                         "bitcoin::secp256k1::Signature" => Some(".into_rust()"),
 904                         "bitcoin::secp256k1::key::SecretKey" if !is_ref => Some(".into_rust()"),
 905                         "bitcoin::secp256k1::key::SecretKey" if is_ref => Some("}[..]).unwrap()"),
 906                         "bitcoin::blockdata::script::Script" if is_ref => Some(".to_slice()))"),
 907                         "bitcoin::blockdata::script::Script" if !is_ref => Some(".into_rust())"),
 908                         "bitcoin::blockdata::transaction::Transaction" => Some(".into_bitcoin()"),
 909                         "bitcoin::blockdata::transaction::TxOut" if !is_ref => Some(".into_rust()"),
 910                         "bitcoin::network::constants::Network" => Some(".into_bitcoin()"),
 911                         "bitcoin::blockdata::block::BlockHeader" => Some(" }).unwrap()"),
 912                         "bitcoin::blockdata::block::Block" => Some(".to_slice()).unwrap()"),
 913
 914                         // Newtypes that we just expose in their original form.
 915                         "bitcoin::hash_types::Txid" if is_ref => Some(" }[..]).unwrap()"),
 916                         "bitcoin::hash_types::Txid" => Some(".data[..]).unwrap()"),
 917                         "bitcoin::hash_types::BlockHash" if !is_ref => Some(".data[..]).unwrap()"),
 918                         "lightning::ln::channelmanager::PaymentHash" if !is_ref => Some(".data)"),
 919                         "lightning::ln::channelmanager::PaymentHash" if is_ref => Some(" })"),
 920                         "lightning::ln::channelmanager::PaymentPreimage" if !is_ref => Some(".data)"),
 921                         "lightning::ln::channelmanager::PaymentPreimage" if is_ref => Some(" })"),
 922                         "lightning::ln::channelmanager::PaymentSecret" => Some(".data)"),
 923
 924                         // List of traits we map (possibly during processing of other files):
 925                         "crate::util::logger::Logger" => Some(""),
 926
 927                         _ => None,
 928                 }.map(|s| s.to_owned())
 929         }
 930
 931         fn to_c_conversion_new_var_from_path<'b>(&self, full_path: &str, is_ref: bool) -> Option<(&'b str, &'b str)> {
 932                 if self.is_primitive(full_path) {
 933                         return None;
 934                 }
 935                 match full_path {
 936                         "[u8]" if is_ref => Some(("crate::c_types::u8slice::from_slice(", ")")),
 937                         "[usize]" if is_ref => Some(("crate::c_types::usizeslice::from_slice(", ")")),
 938
 939                         "bitcoin::blockdata::transaction::Transaction" if is_ref => Some(("::bitcoin::consensus::encode::serialize(", ")")),
 940                         "bitcoin::blockdata::transaction::Transaction" if !is_ref => Some(("::bitcoin::consensus::encode::serialize(&", ")")),
 941                         "bitcoin::blockdata::block::BlockHeader" if is_ref => Some(("{ let mut s = [0u8; 80]; s[..].copy_from_slice(&::bitcoin::consensus::encode::serialize(", ")); s }")),
 942                         "bitcoin::blockdata::block::Block" if is_ref => Some(("::bitcoin::consensus::encode::serialize(", ")")),
 943                         "bitcoin::hash_types::Txid" => None,
 944
 945                         // Override the default since Records contain an fmt with a lifetime:
 946                         // TODO: We should include the other record fields
 947                         "lightning::util::logger::Record" => Some(("std::ffi::CString::new(format!(\"{}\", ", ".args)).unwrap()")),
 948                         _ => None,
 949                 }.map(|s| s.to_owned())
 950         }
 951         fn to_c_conversion_inline_prefix_from_path(&self, full_path: &str, is_ref: bool, _ptr_for_ref: bool) -> Option<String> {
 952                 if self.is_primitive(full_path) {
 953                         return Some("".to_owned());
 954                 }
 955                 match full_path {
 956                         "Result" if !is_ref => Some("local_"),
 957                         "Vec" if !is_ref => Some("local_"),
 958                         "Option" => Some("local_"),
 959
 960                         "[u8; 32]" if !is_ref => Some("crate::c_types::ThirtyTwoBytes { data: "),
 961                         "[u8; 32]" if is_ref => Some("&"),
 962                         "[u8; 16]" if !is_ref => Some("crate::c_types::SixteenBytes { data: "),
 963                         "[u8; 10]" if !is_ref => Some("crate::c_types::TenBytes { data: "),
 964                         "[u8; 4]" if !is_ref => Some("crate::c_types::FourBytes { data: "),
 965                         "[u8; 3]" if is_ref => Some("&"),
 966
 967                         "[u8]" if is_ref => Some("local_"),
 968                         "[usize]" if is_ref => Some("local_"),
 969
 970                         "str" if is_ref => Some(""),
 971                         "String" => Some(""),
 972
 973                         "std::time::Duration" => Some(""),
 974                         "std::io::Error" if !is_ref => Some("crate::c_types::IOError::from_rust("),
 975
 976                         "bitcoin::secp256k1::key::PublicKey" => Some("crate::c_types::PublicKey::from_rust(&"),
 977                         "bitcoin::secp256k1::Signature" => Some("crate::c_types::Signature::from_rust(&"),
 978                         "bitcoin::secp256k1::key::SecretKey" if is_ref  => Some(""),
 979                         "bitcoin::secp256k1::key::SecretKey" if !is_ref => Some("crate::c_types::SecretKey::from_rust("),
 980                         "bitcoin::secp256k1::Error" if !is_ref => Some("crate::c_types::Secp256k1Error::from_rust("),
 981                         "bitcoin::blockdata::script::Script" if is_ref => Some("crate::c_types::u8slice::from_slice(&"),
 982                         "bitcoin::blockdata::script::Script" if !is_ref => Some(""),
 983                         "bitcoin::blockdata::transaction::Transaction" => Some("crate::c_types::Transaction::from_vec(local_"),
 984                         "bitcoin::blockdata::transaction::OutPoint" => Some("crate::c_types::bitcoin_to_C_outpoint("),
 985                         "bitcoin::blockdata::transaction::TxOut" if !is_ref => Some("crate::c_types::TxOut::from_rust("),
 986                         "bitcoin::network::constants::Network" => Some("crate::bitcoin::network::Network::from_bitcoin("),
 987                         "bitcoin::blockdata::block::BlockHeader" if is_ref => Some("&local_"),
 988                         "bitcoin::blockdata::block::Block" if is_ref => Some("crate::c_types::u8slice::from_slice(&local_"),
 989
 990                         "bitcoin::hash_types::Txid" if !is_ref => Some("crate::c_types::ThirtyTwoBytes { data: "),
 991
 992                         // Newtypes that we just expose in their original form.
 993                         "bitcoin::hash_types::Txid" if is_ref => Some(""),
 994                         "bitcoin::hash_types::BlockHash" if is_ref => Some(""),
 995                         "bitcoin::hash_types::BlockHash" => Some("crate::c_types::ThirtyTwoBytes { data: "),
 996                         "bitcoin::secp256k1::Message" if !is_ref => Some("crate::c_types::ThirtyTwoBytes { data: "),
 997                         "lightning::ln::channelmanager::PaymentHash" if is_ref => Some("&"),
 998                         "lightning::ln::channelmanager::PaymentHash" if !is_ref => Some("crate::c_types::ThirtyTwoBytes { data: "),
 999                         "lightning::ln::channelmanager::PaymentPreimage" if is_ref => Some("&"),
1000                         "lightning::ln::channelmanager::PaymentPreimage" => Some("crate::c_types::ThirtyTwoBytes { data: "),
1001                         "lightning::ln::channelmanager::PaymentSecret" if !is_ref => Some("crate::c_types::ThirtyTwoBytes { data: "),
1002
1003                         // Override the default since Records contain an fmt with a lifetime:
1004                         "lightning::util::logger::Record" => Some("local_"),
1005
1006                         _ => None,
1007                 }.map(|s| s.to_owned())
1008         }
1009         fn to_c_conversion_inline_suffix_from_path(&self, full_path: &str, is_ref: bool, _ptr_for_ref: bool) -> Option<String> {
1010                 if self.is_primitive(full_path) {
1011                         return Some("".to_owned());
1012                 }
1013                 match full_path {
1014                         "Result" if !is_ref => Some(""),
1015                         "Vec" if !is_ref => Some(".into()"),
1016                         "Option" => Some(""),
1017
1018                         "[u8; 32]" if !is_ref => Some(" }"),
1019                         "[u8; 32]" if is_ref => Some(""),
1020                         "[u8; 16]" if !is_ref => Some(" }"),
1021                         "[u8; 10]" if !is_ref => Some(" }"),
1022                         "[u8; 4]" if !is_ref => Some(" }"),
1023                         "[u8; 3]" if is_ref => Some(""),
1024
1025                         "[u8]" if is_ref => Some(""),
1026                         "[usize]" if is_ref => Some(""),
1027
1028                         "str" if is_ref => Some(".into()"),
1029                         "String" if !is_ref => Some(".into_bytes().into()"),
1030                         "String" if is_ref => Some(".as_str().into()"),
1031
1032                         "std::time::Duration" => Some(".as_secs()"),
1033                         "std::io::Error" if !is_ref => Some(")"),
1034
1035                         "bitcoin::secp256k1::key::PublicKey" => Some(")"),
1036                         "bitcoin::secp256k1::Signature" => Some(")"),
1037                         "bitcoin::secp256k1::key::SecretKey" if !is_ref => Some(")"),
1038                         "bitcoin::secp256k1::key::SecretKey" if is_ref => Some(".as_ref()"),
1039                         "bitcoin::secp256k1::Error" if !is_ref => Some(")"),
1040                         "bitcoin::blockdata::script::Script" if is_ref => Some("[..])"),
1041                         "bitcoin::blockdata::script::Script" if !is_ref => Some(".into_bytes().into()"),
1042                         "bitcoin::blockdata::transaction::Transaction" => Some(")"),
1043                         "bitcoin::blockdata::transaction::OutPoint" => Some(")"),
1044                         "bitcoin::blockdata::transaction::TxOut" if !is_ref => Some(")"),
1045                         "bitcoin::network::constants::Network" => Some(")"),
1046                         "bitcoin::blockdata::block::BlockHeader" if is_ref => Some(""),
1047                         "bitcoin::blockdata::block::Block" if is_ref => Some(")"),
1048
1049                         "bitcoin::hash_types::Txid" if !is_ref => Some(".into_inner() }"),
1050
1051                         // Newtypes that we just expose in their original form.
1052                         "bitcoin::hash_types::Txid" if is_ref => Some(".as_inner()"),
1053                         "bitcoin::hash_types::BlockHash" if is_ref => Some(".as_inner()"),
1054                         "bitcoin::hash_types::BlockHash" => Some(".into_inner() }"),
1055                         "bitcoin::secp256k1::Message" if !is_ref => Some(".as_ref().clone() }"),
1056                         "lightning::ln::channelmanager::PaymentHash" if is_ref => Some(".0"),
1057                         "lightning::ln::channelmanager::PaymentHash" => Some(".0 }"),
1058                         "lightning::ln::channelmanager::PaymentPreimage" if is_ref => Some(".0"),
1059                         "lightning::ln::channelmanager::PaymentPreimage" => Some(".0 }"),
1060                         "lightning::ln::channelmanager::PaymentSecret" if !is_ref => Some(".0 }"),
1061
1062                         // Override the default since Records contain an fmt with a lifetime:
1063                         "lightning::util::logger::Record" => Some(".as_ptr()"),
1064
1065                         _ => None,
1066                 }.map(|s| s.to_owned())
1067         }
1068
1069         fn empty_val_check_suffix_from_path(&self, full_path: &str) -> Option<&str> {
1070                 match full_path {
1071                         "lightning::ln::channelmanager::PaymentSecret" => Some(".data == [0; 32]"),
1072                         "bitcoin::secp256k1::key::PublicKey" => Some(".is_null()"),
1073                         "bitcoin::secp256k1::Signature" => Some(".is_null()"),
1074                         _ => None
1075                 }
1076         }
1077
1078         // ****************************
1079         // *** Container Processing ***
1080         // ****************************
1081
1082         /// Returns the module path in the generated mapping crate to the containers which we generate
1083         /// when writing to CrateTypes::template_file.
1084         pub fn generated_container_path() -> &'static str {
1085                 "crate::c_types::derived"
1086         }
1087         /// Returns the module path in the generated mapping crate to the container templates, which
1088         /// are then concretized and put in the generated container path/template_file.
1089         fn container_templ_path() -> &'static str {
1090                 "crate::c_types"
1091         }
1092
1093         /// Returns true if the path containing the given args is a "transparent" container, ie an
1094         /// Option or a container which does not require a generated continer class.
1095         fn is_transparent_container<'i, I: Iterator<Item=&'i syn::Type>>(&self, full_path: &str, _is_ref: bool, mut args: I) -> bool {
1096                 if full_path == "Option" {
1097                         let inner = args.next().unwrap();
1098                         assert!(args.next().is_none());
1099                         match inner {
1100                                 syn::Type::Reference(_) => true,
1101                                 syn::Type::Path(p) => {
1102                                         if let Some(resolved) = self.maybe_resolve_path(&p.path, None) {
1103                                                 if self.is_primitive(&resolved) { false } else { true }
1104                                         } else { true }
1105                                 },
1106                                 syn::Type::Tuple(_) => false,
1107                                 _ => unimplemented!(),
1108                         }
1109                 } else { false }
1110         }
1111         /// Returns true if the path is a "transparent" container, ie an Option or a container which does
1112         /// not require a generated continer class.
1113         fn is_path_transparent_container(&self, full_path: &syn::Path, generics: Option<&GenericTypes>, is_ref: bool) -> bool {
1114                 let inner_iter = match &full_path.segments.last().unwrap().arguments {
1115                         syn::PathArguments::None => return false,
1116                         syn::PathArguments::AngleBracketed(args) => args.args.iter().map(|arg| {
1117                                 if let syn::GenericArgument::Type(ref ty) = arg {
1118                                         ty
1119                                 } else { unimplemented!() }
1120                         }),
1121                         syn::PathArguments::Parenthesized(_) => unimplemented!(),
1122                 };
1123                 self.is_transparent_container(&self.resolve_path(full_path, generics), is_ref, inner_iter)
1124         }
1125         /// Returns true if this is a known, supported, non-transparent container.
1126         fn is_known_container(&self, full_path: &str, is_ref: bool) -> bool {
1127                 (full_path == "Result" && !is_ref) || (full_path == "Vec" && !is_ref) || full_path.ends_with("Tuple") || full_path == "Option"
1128         }
1129         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)
1130                         // Returns prefix + Vec<(prefix, var-name-to-inline-convert)> + suffix
1131                         // expecting one element in the vec per generic type, each of which is inline-converted
1132                         -> Option<(&'b str, Vec<(String, String)>, &'b str, ContainerPrefixLocation)> {
1133                 match full_path {
1134                         "Result" if !is_ref => {
1135                                 Some(("match ",
1136                                                 vec![(" { Ok(mut o) => crate::c_types::CResultTempl::ok(".to_string(), "o".to_string()),
1137                                                         (").into(), Err(mut e) => crate::c_types::CResultTempl::err(".to_string(), "e".to_string())],
1138                                                 ").into() }", ContainerPrefixLocation::PerConv))
1139                         },
1140                         "Vec" if !is_ref => {
1141                                 Some(("Vec::new(); for mut item in ", vec![(format!(".drain(..) {{ local_{}.push(", var_name), "item".to_string())], "); }", ContainerPrefixLocation::PerConv))
1142                         },
1143                         "Slice" => {
1144                                 Some(("Vec::new(); for item in ", vec![(format!(".iter() {{ local_{}.push(", var_name), "**item".to_string())], "); }", ContainerPrefixLocation::PerConv))
1145                         },
1146                         "Option" => {
1147                                 if let Some(syn::Type::Path(p)) = single_contained {
1148                                         let inner_path = self.resolve_path(&p.path, generics);
1149                                         if self.is_primitive(&inner_path) {
1150                                                 return Some(("if ", vec![
1151                                                         (format!(".is_none() {{ {}::COption_{}Z::None }} else {{ ", Self::generated_container_path(), inner_path),
1152                                                          format!("{}::COption_{}Z::Some({}.unwrap())", Self::generated_container_path(), inner_path, var_access))
1153                                                         ], " }", ContainerPrefixLocation::NoPrefix));
1154                                         } else if self.c_type_has_inner_from_path(&inner_path) {
1155                                                 if is_ref {
1156                                                         return Some(("if ", vec![
1157                                                                 (".is_none() { std::ptr::null() } else { ".to_owned(), format!("({}.as_ref().unwrap())", var_access))
1158                                                                 ], " }", ContainerPrefixLocation::OutsideConv));
1159                                                 } else {
1160                                                         return Some(("if ", vec![
1161                                                                 (".is_none() { std::ptr::null_mut() } else { ".to_owned(), format!("({}.unwrap())", var_access))
1162                                                                 ], " }", ContainerPrefixLocation::OutsideConv));
1163                                                 }
1164                                         }
1165                                 }
1166                                 if let Some(t) = single_contained {
1167                                         let mut v = Vec::new();
1168                                         self.write_empty_rust_val(generics, &mut v, t);
1169                                         let s = String::from_utf8(v).unwrap();
1170                                         return Some(("if ", vec![
1171                                                 (format!(".is_none() {{ {} }} else {{ ", s), format!("({}.unwrap())", var_access))
1172                                                 ], " }", ContainerPrefixLocation::PerConv));
1173                                 } else { unreachable!(); }
1174                         },
1175                         _ => None,
1176                 }
1177         }
1178
1179         /// only_contained_has_inner implies that there is only one contained element in the container
1180         /// and it has an inner field (ie is an "opaque" type we've defined).
1181         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)
1182                         // Returns prefix + Vec<(prefix, var-name-to-inline-convert)> + suffix
1183                         // expecting one element in the vec per generic type, each of which is inline-converted
1184                         -> Option<(&'b str, Vec<(String, String)>, &'b str, ContainerPrefixLocation)> {
1185                 match full_path {
1186                         "Result" if !is_ref => {
1187                                 Some(("match ",
1188                                                 vec![(".result_ok { true => Ok(".to_string(), format!("(*unsafe {{ Box::from_raw(<*mut _>::take_ptr(&mut {}.contents.result)) }})", var_access)),
1189                                                      ("), false => Err(".to_string(), format!("(*unsafe {{ Box::from_raw(<*mut _>::take_ptr(&mut {}.contents.err)) }})", var_access))],
1190                                                 ")}", ContainerPrefixLocation::PerConv))
1191                         },
1192                         "Slice" if is_ref => {
1193                                 Some(("Vec::new(); for mut item in ", vec![(format!(".as_slice().iter() {{ local_{}.push(", var_name), "item".to_string())], "); }", ContainerPrefixLocation::PerConv))
1194                         },
1195                         "Vec"|"Slice" => {
1196                                 Some(("Vec::new(); for mut item in ", vec![(format!(".into_rust().drain(..) {{ local_{}.push(", var_name), "item".to_string())], "); }", ContainerPrefixLocation::PerConv))
1197                         },
1198                         "Option" => {
1199                                 if let Some(syn::Type::Path(p)) = single_contained {
1200                                         let inner_path = self.resolve_path(&p.path, generics);
1201                                         if self.is_primitive(&inner_path) {
1202                                                 return Some(("if ", vec![(".is_some() { Some(".to_string(), format!("{}.take()", var_access))], ") } else { None }", ContainerPrefixLocation::NoPrefix))
1203                                         } else if self.c_type_has_inner_from_path(&inner_path) {
1204                                                 if is_ref {
1205                                                         return Some(("if ", vec![(".inner.is_null() { None } else { Some((*".to_string(), format!("{}", var_access))], ").clone()) }", ContainerPrefixLocation::PerConv))
1206                                                 } else {
1207                                                         return Some(("if ", vec![(".inner.is_null() { None } else { Some(".to_string(), format!("{}", var_access))], ") }", ContainerPrefixLocation::PerConv));
1208                                                 }
1209                                         }
1210                                 }
1211
1212                                 if let Some(t) = single_contained {
1213                                         match t {
1214                                                 syn::Type::Reference(_)|syn::Type::Path(_)|syn::Type::Slice(_) => {
1215                                                         let mut v = Vec::new();
1216                                                         let ret_ref = self.write_empty_rust_val_check_suffix(generics, &mut v, t);
1217                                                         let s = String::from_utf8(v).unwrap();
1218                                                         match ret_ref {
1219                                                                 EmptyValExpectedTy::ReferenceAsPointer =>
1220                                                                         return Some(("if ", vec![
1221                                                                                 (format!("{} {{ None }} else {{ Some(", s), format!("unsafe {{ &mut *{} }}", var_access))
1222                                                                         ], ") }", ContainerPrefixLocation::NoPrefix)),
1223                                                                 EmptyValExpectedTy::OwnedPointer => {
1224                                                                         if let syn::Type::Slice(_) = t {
1225                                                                                         panic!();
1226                                                                         }
1227                                                                         return Some(("if ", vec![
1228                                                                                 (format!("{} {{ None }} else {{ Some(", s), format!("unsafe {{ *Box::from_raw({}) }}", var_access))
1229                                                                         ], ") }", ContainerPrefixLocation::NoPrefix));
1230                                                                 }
1231                                                                 EmptyValExpectedTy::NonPointer =>
1232                                                                         return Some(("if ", vec![
1233                                                                                 (format!("{} {{ None }} else {{ Some(", s), format!("{}", var_access))
1234                                                                         ], ") }", ContainerPrefixLocation::PerConv)),
1235                                                         }
1236                                                 },
1237                                                 syn::Type::Tuple(_) => {
1238                                                         return Some(("if ", vec![(".is_some() { Some(".to_string(), format!("{}.take()", var_access))], ") } else { None }", ContainerPrefixLocation::PerConv))
1239                                                 },
1240                                                 _ => unimplemented!(),
1241                                         }
1242                                 } else { unreachable!(); }
1243                         },
1244                         _ => None,
1245                 }
1246         }
1247
1248         // *************************************************
1249         // *** Type definition during main.rs processing ***
1250         // *************************************************
1251
1252         pub fn get_declared_type(&'a self, ident: &syn::Ident) -> Option<&'a DeclType<'c>> {
1253                 self.types.get_declared_type(ident)
1254         }
1255         /// Returns true if the object at the given path is mapped as X { inner: *mut origX, .. }.
1256         pub fn c_type_has_inner_from_path(&self, full_path: &str) -> bool{
1257                 self.crate_types.opaques.get(full_path).is_some()
1258         }
1259
1260         pub fn maybe_resolve_ident(&self, id: &syn::Ident) -> Option<String> {
1261                 self.types.maybe_resolve_ident(id)
1262         }
1263
1264         pub fn maybe_resolve_non_ignored_ident(&self, id: &syn::Ident) -> Option<String> {
1265                 self.types.maybe_resolve_non_ignored_ident(id)
1266         }
1267
1268         pub fn maybe_resolve_path(&self, p_arg: &syn::Path, generics: Option<&GenericTypes>) -> Option<String> {
1269                 self.types.maybe_resolve_path(p_arg, generics)
1270         }
1271         pub fn resolve_path(&self, p: &syn::Path, generics: Option<&GenericTypes>) -> String {
1272                 self.maybe_resolve_path(p, generics).unwrap()
1273         }
1274
1275         // ***********************************
1276         // *** Original Rust Type Printing ***
1277         // ***********************************
1278
1279         fn in_rust_prelude(resolved_path: &str) -> bool {
1280                 match resolved_path {
1281                         "Vec" => true,
1282                         "Result" => true,
1283                         "Option" => true,
1284                         _ => false,
1285                 }
1286         }
1287
1288         fn write_rust_path<W: std::io::Write>(&self, w: &mut W, generics_resolver: Option<&GenericTypes>, path: &syn::Path) {
1289                 if let Some(resolved) = self.maybe_resolve_path(&path, generics_resolver) {
1290                         if self.is_primitive(&resolved) {
1291                                 write!(w, "{}", path.get_ident().unwrap()).unwrap();
1292                         } else {
1293                                 // TODO: We should have a generic "is from a dependency" check here instead of
1294                                 // checking for "bitcoin" explicitly.
1295                                 if resolved.starts_with("bitcoin::") || Self::in_rust_prelude(&resolved) {
1296                                         write!(w, "{}", resolved).unwrap();
1297                                 // If we're printing a generic argument, it needs to reference the crate, otherwise
1298                                 // the original crate:
1299                                 } else if self.maybe_resolve_path(&path, None).as_ref() == Some(&resolved) {
1300                                         write!(w, "{}", resolved).unwrap();
1301                                 } else {
1302                                         write!(w, "crate::{}", resolved).unwrap();
1303                                 }
1304                         }
1305                         if let syn::PathArguments::AngleBracketed(args) = &path.segments.iter().last().unwrap().arguments {
1306                                 self.write_rust_generic_arg(w, generics_resolver, args.args.iter());
1307                         }
1308                 } else {
1309                         if path.leading_colon.is_some() {
1310                                 write!(w, "::").unwrap();
1311                         }
1312                         for (idx, seg) in path.segments.iter().enumerate() {
1313                                 if idx != 0 { write!(w, "::").unwrap(); }
1314                                 write!(w, "{}", seg.ident).unwrap();
1315                                 if let syn::PathArguments::AngleBracketed(args) = &seg.arguments {
1316                                         self.write_rust_generic_arg(w, generics_resolver, args.args.iter());
1317                                 }
1318                         }
1319                 }
1320         }
1321         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>) {
1322                 let mut had_params = false;
1323                 for (idx, arg) in generics.enumerate() {
1324                         if idx != 0 { write!(w, ", ").unwrap(); } else { write!(w, "<").unwrap(); }
1325                         had_params = true;
1326                         match arg {
1327                                 syn::GenericParam::Lifetime(lt) => write!(w, "'{}", lt.lifetime.ident).unwrap(),
1328                                 syn::GenericParam::Type(t) => {
1329                                         write!(w, "{}", t.ident).unwrap();
1330                                         if t.colon_token.is_some() { write!(w, ":").unwrap(); }
1331                                         for (idx, bound) in t.bounds.iter().enumerate() {
1332                                                 if idx != 0 { write!(w, " + ").unwrap(); }
1333                                                 match bound {
1334                                                         syn::TypeParamBound::Trait(tb) => {
1335                                                                 if tb.paren_token.is_some() || tb.lifetimes.is_some() { unimplemented!(); }
1336                                                                 self.write_rust_path(w, generics_resolver, &tb.path);
1337                                                         },
1338                                                         _ => unimplemented!(),
1339                                                 }
1340                                         }
1341                                         if t.eq_token.is_some() || t.default.is_some() { unimplemented!(); }
1342                                 },
1343                                 _ => unimplemented!(),
1344                         }
1345                 }
1346                 if had_params { write!(w, ">").unwrap(); }
1347         }
1348
1349         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>) {
1350                 write!(w, "<").unwrap();
1351                 for (idx, arg) in generics.enumerate() {
1352                         if idx != 0 { write!(w, ", ").unwrap(); }
1353                         match arg {
1354                                 syn::GenericArgument::Type(t) => self.write_rust_type(w, generics_resolver, t),
1355                                 _ => unimplemented!(),
1356                         }
1357                 }
1358                 write!(w, ">").unwrap();
1359         }
1360         pub fn write_rust_type<W: std::io::Write>(&self, w: &mut W, generics: Option<&GenericTypes>, t: &syn::Type) {
1361                 match t {
1362                         syn::Type::Path(p) => {
1363                                 if p.qself.is_some() {
1364                                         unimplemented!();
1365                                 }
1366                                 self.write_rust_path(w, generics, &p.path);
1367                         },
1368                         syn::Type::Reference(r) => {
1369                                 write!(w, "&").unwrap();
1370                                 if let Some(lft) = &r.lifetime {
1371                                         write!(w, "'{} ", lft.ident).unwrap();
1372                                 }
1373                                 if r.mutability.is_some() {
1374                                         write!(w, "mut ").unwrap();
1375                                 }
1376                                 self.write_rust_type(w, generics, &*r.elem);
1377                         },
1378                         syn::Type::Array(a) => {
1379                                 write!(w, "[").unwrap();
1380                                 self.write_rust_type(w, generics, &a.elem);
1381                                 if let syn::Expr::Lit(l) = &a.len {
1382                                         if let syn::Lit::Int(i) = &l.lit {
1383                                                 write!(w, "; {}]", i).unwrap();
1384                                         } else { unimplemented!(); }
1385                                 } else { unimplemented!(); }
1386                         }
1387                         syn::Type::Slice(s) => {
1388                                 write!(w, "[").unwrap();
1389                                 self.write_rust_type(w, generics, &s.elem);
1390                                 write!(w, "]").unwrap();
1391                         },
1392                         syn::Type::Tuple(s) => {
1393                                 write!(w, "(").unwrap();
1394                                 for (idx, t) in s.elems.iter().enumerate() {
1395                                         if idx != 0 { write!(w, ", ").unwrap(); }
1396                                         self.write_rust_type(w, generics, &t);
1397                                 }
1398                                 write!(w, ")").unwrap();
1399                         },
1400                         _ => unimplemented!(),
1401                 }
1402         }
1403
1404         /// Prints a constructor for something which is "uninitialized" (but obviously not actually
1405         /// unint'd memory).
1406         pub fn write_empty_rust_val<W: std::io::Write>(&self, generics: Option<&GenericTypes>, w: &mut W, t: &syn::Type) {
1407                 match t {
1408                         syn::Type::Path(p) => {
1409                                 let resolved = self.resolve_path(&p.path, generics);
1410                                 if self.crate_types.opaques.get(&resolved).is_some() {
1411                                         write!(w, "crate::{} {{ inner: std::ptr::null_mut(), is_owned: true }}", resolved).unwrap();
1412                                 } else {
1413                                         // Assume its a manually-mapped C type, where we can just define an null() fn
1414                                         write!(w, "{}::null()", self.c_type_from_path(&resolved, false, false).unwrap()).unwrap();
1415                                 }
1416                         },
1417                         syn::Type::Array(a) => {
1418                                 if let syn::Expr::Lit(l) = &a.len {
1419                                         if let syn::Lit::Int(i) = &l.lit {
1420                                                 if i.base10_digits().parse::<usize>().unwrap() < 32 {
1421                                                         // Blindly assume that if we're trying to create an empty value for an
1422                                                         // array < 32 entries that all-0s may be a valid state.
1423                                                         unimplemented!();
1424                                                 }
1425                                                 let arrty = format!("[u8; {}]", i.base10_digits());
1426                                                 write!(w, "{}", self.to_c_conversion_inline_prefix_from_path(&arrty, false, false).unwrap()).unwrap();
1427                                                 write!(w, "[0; {}]", i.base10_digits()).unwrap();
1428                                                 write!(w, "{}", self.to_c_conversion_inline_suffix_from_path(&arrty, false, false).unwrap()).unwrap();
1429                                         } else { unimplemented!(); }
1430                                 } else { unimplemented!(); }
1431                         }
1432                         _ => unimplemented!(),
1433                 }
1434         }
1435
1436         fn is_real_type_array(&self, resolved_type: &str) -> Option<syn::Type> {
1437                 if let Some(real_ty) = self.c_type_from_path(&resolved_type, true, false) {
1438                         if real_ty.ends_with("]") && real_ty.starts_with("*const [u8; ") {
1439                                 let mut split = real_ty.split("; ");
1440                                 split.next().unwrap();
1441                                 let tail_str = split.next().unwrap();
1442                                 assert!(split.next().is_none());
1443                                 let len = &tail_str[..tail_str.len() - 1];
1444                                 Some(syn::Type::Array(syn::TypeArray {
1445                                                 bracket_token: syn::token::Bracket { span: Span::call_site() },
1446                                                 elem: Box::new(syn::Type::Path(syn::TypePath {
1447                                                         qself: None,
1448                                                         path: syn::Path::from(syn::PathSegment::from(syn::Ident::new("u8", Span::call_site()))),
1449                                                 })),
1450                                                 semi_token: syn::Token!(;)(Span::call_site()),
1451                                                 len: syn::Expr::Lit(syn::ExprLit { attrs: Vec::new(), lit: syn::Lit::Int(syn::LitInt::new(len, Span::call_site())) }),
1452                                         }))
1453                         } else { None }
1454                 } else { None }
1455         }
1456
1457         /// Prints a suffix to determine if a variable is empty (ie was set by write_empty_rust_val).
1458         /// See EmptyValExpectedTy for information on return types.
1459         fn write_empty_rust_val_check_suffix<W: std::io::Write>(&self, generics: Option<&GenericTypes>, w: &mut W, t: &syn::Type) -> EmptyValExpectedTy {
1460                 match t {
1461                         syn::Type::Path(p) => {
1462                                 let resolved = self.resolve_path(&p.path, generics);
1463                                 if let Some(arr_ty) = self.is_real_type_array(&resolved) {
1464                                         write!(w, ".data").unwrap();
1465                                         return self.write_empty_rust_val_check_suffix(generics, w, &arr_ty);
1466                                 }
1467                                 if self.crate_types.opaques.get(&resolved).is_some() {
1468                                         write!(w, ".inner.is_null()").unwrap();
1469                                         EmptyValExpectedTy::NonPointer
1470                                 } else {
1471                                         if let Some(suffix) = self.empty_val_check_suffix_from_path(&resolved) {
1472                                                 write!(w, "{}", suffix).unwrap();
1473                                                 // We may eventually need to allow empty_val_check_suffix_from_path to specify if we need a deref or not
1474                                                 EmptyValExpectedTy::NonPointer
1475                                         } else {
1476                                                 write!(w, " == std::ptr::null_mut()").unwrap();
1477                                                 EmptyValExpectedTy::OwnedPointer
1478                                         }
1479                                 }
1480                         },
1481                         syn::Type::Array(a) => {
1482                                 if let syn::Expr::Lit(l) = &a.len {
1483                                         if let syn::Lit::Int(i) = &l.lit {
1484                                                 write!(w, " == [0; {}]", i.base10_digits()).unwrap();
1485                                                 EmptyValExpectedTy::NonPointer
1486                                         } else { unimplemented!(); }
1487                                 } else { unimplemented!(); }
1488                         },
1489                         syn::Type::Slice(_) => {
1490                                 // Option<[]> always implies that we want to treat len() == 0 differently from
1491                                 // None, so we always map an Option<[]> into a pointer.
1492                                 write!(w, " == std::ptr::null_mut()").unwrap();
1493                                 EmptyValExpectedTy::ReferenceAsPointer
1494                         },
1495                         _ => unimplemented!(),
1496                 }
1497         }
1498
1499         /// Prints a suffix to determine if a variable is empty (ie was set by write_empty_rust_val).
1500         pub fn write_empty_rust_val_check<W: std::io::Write>(&self, generics: Option<&GenericTypes>, w: &mut W, t: &syn::Type, var_access: &str) {
1501                 match t {
1502                         syn::Type::Path(_) => {
1503                                 write!(w, "{}", var_access).unwrap();
1504                                 self.write_empty_rust_val_check_suffix(generics, w, t);
1505                         },
1506                         syn::Type::Array(a) => {
1507                                 if let syn::Expr::Lit(l) = &a.len {
1508                                         if let syn::Lit::Int(i) = &l.lit {
1509                                                 let arrty = format!("[u8; {}]", i.base10_digits());
1510                                                 // We don't (yet) support a new-var conversion here.
1511                                                 assert!(self.from_c_conversion_new_var_from_path(&arrty, false).is_none());
1512                                                 write!(w, "{}{}{}",
1513                                                         self.from_c_conversion_prefix_from_path(&arrty, false).unwrap(),
1514                                                         var_access,
1515                                                         self.from_c_conversion_suffix_from_path(&arrty, false).unwrap()).unwrap();
1516                                                 self.write_empty_rust_val_check_suffix(generics, w, t);
1517                                         } else { unimplemented!(); }
1518                                 } else { unimplemented!(); }
1519                         }
1520                         _ => unimplemented!(),
1521                 }
1522         }
1523
1524         // ********************************
1525         // *** Type conversion printing ***
1526         // ********************************
1527
1528         /// Returns true we if can just skip passing this to C entirely
1529         pub fn skip_arg(&self, t: &syn::Type, generics: Option<&GenericTypes>) -> bool {
1530                 match t {
1531                         syn::Type::Path(p) => {
1532                                 if p.qself.is_some() { unimplemented!(); }
1533                                 if let Some(full_path) = self.maybe_resolve_path(&p.path, generics) {
1534                                         self.skip_path(&full_path)
1535                                 } else { false }
1536                         },
1537                         syn::Type::Reference(r) => {
1538                                 self.skip_arg(&*r.elem, generics)
1539                         },
1540                         _ => false,
1541                 }
1542         }
1543         pub fn no_arg_to_rust<W: std::io::Write>(&self, w: &mut W, t: &syn::Type, generics: Option<&GenericTypes>) {
1544                 match t {
1545                         syn::Type::Path(p) => {
1546                                 if p.qself.is_some() { unimplemented!(); }
1547                                 if let Some(full_path) = self.maybe_resolve_path(&p.path, generics) {
1548                                         write!(w, "{}", self.no_arg_path_to_rust(&full_path)).unwrap();
1549                                 }
1550                         },
1551                         syn::Type::Reference(r) => {
1552                                 self.no_arg_to_rust(w, &*r.elem, generics);
1553                         },
1554                         _ => {},
1555                 }
1556         }
1557
1558         fn write_conversion_inline_intern<W: std::io::Write,
1559                         LP: Fn(&str, bool, bool) -> Option<String>, DL: Fn(&mut W, &DeclType, &str, bool, bool), SC: Fn(bool) -> &'static str>
1560                         (&self, w: &mut W, t: &syn::Type, generics: Option<&GenericTypes>, is_ref: bool, is_mut: bool, ptr_for_ref: bool,
1561                          tupleconv: &str, prefix: bool, sliceconv: SC, path_lookup: LP, decl_lookup: DL) {
1562                 match t {
1563                         syn::Type::Reference(r) => {
1564                                 self.write_conversion_inline_intern(w, &*r.elem, generics, true, r.mutability.is_some(),
1565                                         ptr_for_ref, tupleconv, prefix, sliceconv, path_lookup, decl_lookup);
1566                         },
1567                         syn::Type::Path(p) => {
1568                                 if p.qself.is_some() {
1569                                         unimplemented!();
1570                                 }
1571
1572                                 let resolved_path = self.resolve_path(&p.path, generics);
1573                                 if let Some(aliased_type) = self.crate_types.type_aliases.get(&resolved_path) {
1574                                         return self.write_conversion_inline_intern(w, aliased_type, None, is_ref, is_mut, ptr_for_ref, tupleconv, prefix, sliceconv, path_lookup, decl_lookup);
1575                                 } else if let Some(c_type) = path_lookup(&resolved_path, is_ref, ptr_for_ref) {
1576                                         write!(w, "{}", c_type).unwrap();
1577                                 } else if self.crate_types.opaques.get(&resolved_path).is_some() {
1578                                         decl_lookup(w, &DeclType::StructImported, &resolved_path, is_ref, is_mut);
1579                                 } else if self.crate_types.mirrored_enums.get(&resolved_path).is_some() {
1580                                         decl_lookup(w, &DeclType::MirroredEnum, &resolved_path, is_ref, is_mut);
1581                                 } else if let Some(t) = self.crate_types.traits.get(&resolved_path) {
1582                                         decl_lookup(w, &DeclType::Trait(t), &resolved_path, is_ref, is_mut);
1583                                 } else if let Some(ident) = single_ident_generic_path_to_ident(&p.path) {
1584                                         if let Some(decl_type) = self.types.maybe_resolve_declared(ident) {
1585                                                 decl_lookup(w, decl_type, &self.maybe_resolve_ident(ident).unwrap(), is_ref, is_mut);
1586                                         } else { unimplemented!(); }
1587                                 } else { unimplemented!(); }
1588                         },
1589                         syn::Type::Array(a) => {
1590                                 // We assume all arrays contain only [int_literal; X]s.
1591                                 // This may result in some outputs not compiling.
1592                                 if let syn::Expr::Lit(l) = &a.len {
1593                                         if let syn::Lit::Int(i) = &l.lit {
1594                                                 write!(w, "{}", path_lookup(&format!("[u8; {}]", i.base10_digits()), is_ref, ptr_for_ref).unwrap()).unwrap();
1595                                         } else { unimplemented!(); }
1596                                 } else { unimplemented!(); }
1597                         },
1598                         syn::Type::Slice(s) => {
1599                                 // We assume all slices contain only literals or references.
1600                                 // This may result in some outputs not compiling.
1601                                 if let syn::Type::Path(p) = &*s.elem {
1602                                         let resolved = self.resolve_path(&p.path, generics);
1603                                         assert!(self.is_primitive(&resolved));
1604                                         write!(w, "{}", path_lookup("[u8]", is_ref, ptr_for_ref).unwrap()).unwrap();
1605                                 } else if let syn::Type::Reference(r) = &*s.elem {
1606                                         if let syn::Type::Path(p) = &*r.elem {
1607                                                 write!(w, "{}", sliceconv(self.c_type_has_inner_from_path(&self.resolve_path(&p.path, generics)))).unwrap();
1608                                         } else { unimplemented!(); }
1609                                 } else if let syn::Type::Tuple(t) = &*s.elem {
1610                                         assert!(!t.elems.is_empty());
1611                                         if prefix {
1612                                                 write!(w, "&local_").unwrap();
1613                                         } else {
1614                                                 let mut needs_map = false;
1615                                                 for e in t.elems.iter() {
1616                                                         if let syn::Type::Reference(_) = e {
1617                                                                 needs_map = true;
1618                                                         }
1619                                                 }
1620                                                 if needs_map {
1621                                                         write!(w, ".iter().map(|(").unwrap();
1622                                                         for i in 0..t.elems.len() {
1623                                                                 write!(w, "{}{}", if i != 0 { ", " } else { "" }, ('a' as u8 + i as u8) as char).unwrap();
1624                                                         }
1625                                                         write!(w, ")| (").unwrap();
1626                                                         for (idx, e) in t.elems.iter().enumerate() {
1627                                                                 if let syn::Type::Reference(_) = e {
1628                                                                         write!(w, "{}{}", if idx != 0 { ", " } else { "" }, (idx as u8 + 'a' as u8) as char).unwrap();
1629                                                                 } else if let syn::Type::Path(_) = e {
1630                                                                         write!(w, "{}*{}", if idx != 0 { ", " } else { "" }, (idx as u8 + 'a' as u8) as char).unwrap();
1631                                                                 } else { unimplemented!(); }
1632                                                         }
1633                                                         write!(w, ")).collect::<Vec<_>>()[..]").unwrap();
1634                                                 }
1635                                         }
1636                                 } else { unimplemented!(); }
1637                         },
1638                         syn::Type::Tuple(t) => {
1639                                 if t.elems.is_empty() {
1640                                         // cbindgen has poor support for (), see, eg https://github.com/eqrion/cbindgen/issues/527
1641                                         // so work around it by just pretending its a 0u8
1642                                         write!(w, "{}", tupleconv).unwrap();
1643                                 } else {
1644                                         if prefix { write!(w, "local_").unwrap(); }
1645                                 }
1646                         },
1647                         _ => unimplemented!(),
1648                 }
1649         }
1650
1651         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) {
1652                 self.write_conversion_inline_intern(w, t, generics, is_ref, false, ptr_for_ref, "0u8 /*", true, |_| "local_",
1653                                 |a, b, c| self.to_c_conversion_inline_prefix_from_path(a, b, c),
1654                                 |w, decl_type, decl_path, is_ref, _is_mut| {
1655                                         match decl_type {
1656                                                 DeclType::MirroredEnum if is_ref && ptr_for_ref => write!(w, "crate::{}::from_native(&", decl_path).unwrap(),
1657                                                 DeclType::MirroredEnum if is_ref => write!(w, "&crate::{}::from_native(&", decl_path).unwrap(),
1658                                                 DeclType::MirroredEnum => write!(w, "crate::{}::native_into(", decl_path).unwrap(),
1659                                                 DeclType::EnumIgnored|DeclType::StructImported if is_ref && ptr_for_ref && from_ptr =>
1660                                                         write!(w, "crate::{} {{ inner: unsafe {{ (", decl_path).unwrap(),
1661                                                 DeclType::EnumIgnored|DeclType::StructImported if is_ref && ptr_for_ref =>
1662                                                         write!(w, "crate::{} {{ inner: unsafe {{ ( (&(", decl_path).unwrap(),
1663                                                 DeclType::EnumIgnored|DeclType::StructImported if is_ref =>
1664                                                         write!(w, "&crate::{} {{ inner: unsafe {{ (", decl_path).unwrap(),
1665                                                 DeclType::EnumIgnored|DeclType::StructImported if !is_ref && from_ptr =>
1666                                                         write!(w, "crate::{} {{ inner: ", decl_path).unwrap(),
1667                                                 DeclType::EnumIgnored|DeclType::StructImported if !is_ref =>
1668                                                         write!(w, "crate::{} {{ inner: Box::into_raw(Box::new(", decl_path).unwrap(),
1669                                                 DeclType::Trait(_) if is_ref => write!(w, "&").unwrap(),
1670                                                 DeclType::Trait(_) if !is_ref => {},
1671                                                 _ => panic!("{:?}", decl_path),
1672                                         }
1673                                 });
1674         }
1675         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) {
1676                 self.write_to_c_conversion_inline_prefix_inner(w, t, generics, false, ptr_for_ref, false);
1677         }
1678         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) {
1679                 self.write_conversion_inline_intern(w, t, generics, is_ref, false, ptr_for_ref, "*/", false, |_| ".into()",
1680                                 |a, b, c| self.to_c_conversion_inline_suffix_from_path(a, b, c),
1681                                 |w, decl_type, _full_path, is_ref, _is_mut| match decl_type {
1682                                         DeclType::MirroredEnum => write!(w, ")").unwrap(),
1683                                         DeclType::EnumIgnored|DeclType::StructImported if is_ref && ptr_for_ref && from_ptr =>
1684                                                 write!(w, " as *const _) as *mut _ }}, is_owned: false }}").unwrap(),
1685                                         DeclType::EnumIgnored|DeclType::StructImported if is_ref && ptr_for_ref =>
1686                                                 write!(w, ") as *const _) as *mut _) }}, is_owned: false }}").unwrap(),
1687                                         DeclType::EnumIgnored|DeclType::StructImported if is_ref =>
1688                                                 write!(w, " as *const _) as *mut _ }}, is_owned: false }}").unwrap(),
1689                                         DeclType::EnumIgnored|DeclType::StructImported if !is_ref && from_ptr =>
1690                                                 write!(w, ", is_owned: true }}").unwrap(),
1691                                         DeclType::EnumIgnored|DeclType::StructImported if !is_ref => write!(w, ")), is_owned: true }}").unwrap(),
1692                                         DeclType::Trait(_) if is_ref => {},
1693                                         DeclType::Trait(_) => {
1694                                                 // This is used when we're converting a concrete Rust type into a C trait
1695                                                 // for use when a Rust trait method returns an associated type.
1696                                                 // Because all of our C traits implement From<RustTypesImplementingTraits>
1697                                                 // we can just call .into() here and be done.
1698                                                 write!(w, ".into()").unwrap()
1699                                         },
1700                                         _ => unimplemented!(),
1701                                 });
1702         }
1703         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) {
1704                 self.write_to_c_conversion_inline_suffix_inner(w, t, generics, false, ptr_for_ref, false);
1705         }
1706
1707         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) {
1708                 self.write_conversion_inline_intern(w, t, generics, is_ref, false, false, "() /*", true, |_| "&local_",
1709                                 |a, b, _c| self.from_c_conversion_prefix_from_path(a, b),
1710                                 |w, decl_type, _full_path, is_ref, is_mut| match decl_type {
1711                                         DeclType::StructImported if is_ref && ptr_for_ref => write!(w, "unsafe {{ &*(*").unwrap(),
1712                                         DeclType::StructImported if is_mut && is_ref => write!(w, "unsafe {{ &mut *").unwrap(),
1713                                         DeclType::StructImported if is_ref => write!(w, "unsafe {{ &*").unwrap(),
1714                                         DeclType::StructImported if !is_ref => write!(w, "*unsafe {{ Box::from_raw(").unwrap(),
1715                                         DeclType::MirroredEnum if is_ref => write!(w, "&").unwrap(),
1716                                         DeclType::MirroredEnum => {},
1717                                         DeclType::Trait(_) => {},
1718                                         _ => unimplemented!(),
1719                                 });
1720         }
1721         pub fn write_from_c_conversion_prefix<W: std::io::Write>(&self, w: &mut W, t: &syn::Type, generics: Option<&GenericTypes>) {
1722                 self.write_from_c_conversion_prefix_inner(w, t, generics, false, false);
1723         }
1724         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) {
1725                 self.write_conversion_inline_intern(w, t, generics, is_ref, false, false, "*/", false,
1726                                 |has_inner| match has_inner {
1727                                         false => ".iter().collect::<Vec<_>>()[..]",
1728                                         true => "[..]",
1729                                 },
1730                                 |a, b, _c| self.from_c_conversion_suffix_from_path(a, b),
1731                                 |w, decl_type, _full_path, is_ref, _is_mut| match decl_type {
1732                                         DeclType::StructImported if is_ref && ptr_for_ref => write!(w, ").inner }}").unwrap(),
1733                                         DeclType::StructImported if is_ref => write!(w, ".inner }}").unwrap(),
1734                                         DeclType::StructImported if !is_ref => write!(w, ".take_inner()) }}").unwrap(),
1735                                         DeclType::MirroredEnum if is_ref => write!(w, ".to_native()").unwrap(),
1736                                         DeclType::MirroredEnum => write!(w, ".into_native()").unwrap(),
1737                                         DeclType::Trait(_) => {},
1738                                         _ => unimplemented!(),
1739                                 });
1740         }
1741         pub fn write_from_c_conversion_suffix<W: std::io::Write>(&self, w: &mut W, t: &syn::Type, generics: Option<&GenericTypes>) {
1742                 self.write_from_c_conversion_suffix_inner(w, t, generics, false, false);
1743         }
1744         // Note that compared to the above conversion functions, the following two are generally
1745         // significantly undertested:
1746         pub fn write_from_c_conversion_to_ref_prefix<W: std::io::Write>(&self, w: &mut W, t: &syn::Type, generics: Option<&GenericTypes>) {
1747                 self.write_conversion_inline_intern(w, t, generics, false, false, false, "() /*", true, |_| "&local_",
1748                                 |a, b, _c| {
1749                                         if let Some(conv) = self.from_c_conversion_prefix_from_path(a, b) {
1750                                                 Some(format!("&{}", conv))
1751                                         } else { None }
1752                                 },
1753                                 |w, decl_type, _full_path, is_ref, _is_mut| match decl_type {
1754                                         DeclType::StructImported if !is_ref => write!(w, "unsafe {{ &*").unwrap(),
1755                                         _ => unimplemented!(),
1756                                 });
1757         }
1758         pub fn write_from_c_conversion_to_ref_suffix<W: std::io::Write>(&self, w: &mut W, t: &syn::Type, generics: Option<&GenericTypes>) {
1759                 self.write_conversion_inline_intern(w, t, generics, false, false, false, "*/", false,
1760                                 |has_inner| match has_inner {
1761                                         false => ".iter().collect::<Vec<_>>()[..]",
1762                                         true => "[..]",
1763                                 },
1764                                 |a, b, _c| self.from_c_conversion_suffix_from_path(a, b),
1765                                 |w, decl_type, _full_path, is_ref, _is_mut| match decl_type {
1766                                         DeclType::StructImported if !is_ref => write!(w, ".inner }}").unwrap(),
1767                                         _ => unimplemented!(),
1768                                 });
1769         }
1770
1771         fn write_conversion_new_var_intern<'b, W: std::io::Write,
1772                 LP: Fn(&str, bool) -> Option<(&str, &str)>,
1773                 LC: Fn(&str, bool, Option<&syn::Type>, &syn::Ident, &str) ->  Option<(&'b str, Vec<(String, String)>, &'b str, ContainerPrefixLocation)>,
1774                 VP: Fn(&mut W, &syn::Type, Option<&GenericTypes>, bool, bool, bool),
1775                 VS: Fn(&mut W, &syn::Type, Option<&GenericTypes>, bool, bool, bool)>
1776                         (&self, w: &mut W, ident: &syn::Ident, var: &str, t: &syn::Type, generics: Option<&GenericTypes>,
1777                          mut is_ref: bool, mut ptr_for_ref: bool, to_c: bool,
1778                          path_lookup: &LP, container_lookup: &LC, var_prefix: &VP, var_suffix: &VS) -> bool {
1779
1780                 macro_rules! convert_container {
1781                         ($container_type: expr, $args_len: expr, $args_iter: expr) => { {
1782                                 // For slices (and Options), we refuse to directly map them as is_ref when they
1783                                 // aren't opaque types containing an inner pointer. This is due to the fact that,
1784                                 // in both cases, the actual higher-level type is non-is_ref.
1785                                 let ty_has_inner = if $args_len == 1 {
1786                                         let ty = $args_iter().next().unwrap();
1787                                         if $container_type == "Slice" && to_c {
1788                                                 // "To C ptr_for_ref" means "return the regular object with is_owned
1789                                                 // set to false", which is totally what we want in a slice if we're about to
1790                                                 // set ty_has_inner.
1791                                                 ptr_for_ref = true;
1792                                         }
1793                                         if let syn::Type::Reference(t) = ty {
1794                                                 if let syn::Type::Path(p) = &*t.elem {
1795                                                         self.c_type_has_inner_from_path(&self.resolve_path(&p.path, generics))
1796                                                 } else { false }
1797                                         } else if let syn::Type::Path(p) = ty {
1798                                                 self.c_type_has_inner_from_path(&self.resolve_path(&p.path, generics))
1799                                         } else { false }
1800                                 } else { true };
1801
1802                                 // Options get a bunch of special handling, since in general we map Option<>al
1803                                 // types into the same C type as non-Option-wrapped types. This ends up being
1804                                 // pretty manual here and most of the below special-cases are for Options.
1805                                 let mut needs_ref_map = false;
1806                                 let mut only_contained_type = None;
1807                                 let mut only_contained_has_inner = false;
1808                                 let mut contains_slice = false;
1809                                 if $args_len == 1 {
1810                                         only_contained_has_inner = ty_has_inner;
1811                                         let arg = $args_iter().next().unwrap();
1812                                         if let syn::Type::Reference(t) = arg {
1813                                                 only_contained_type = Some(&*t.elem);
1814                                                 if let syn::Type::Path(_) = &*t.elem {
1815                                                         is_ref = true;
1816                                                 } else if let syn::Type::Slice(_) = &*t.elem {
1817                                                         contains_slice = true;
1818                                                 } else { return false; }
1819                                                 // If the inner element contains an inner pointer, we will just use that,
1820                                                 // avoiding the need to map elements to references. Otherwise we'll need to
1821                                                 // do an extra mapping step.
1822                                                 needs_ref_map = !only_contained_has_inner;
1823                                         } else {
1824                                                 only_contained_type = Some(&arg);
1825                                         }
1826                                 }
1827
1828                                 if let Some((prefix, conversions, suffix, prefix_location)) = container_lookup(&$container_type, is_ref && ty_has_inner, only_contained_type, ident, var) {
1829                                         assert_eq!(conversions.len(), $args_len);
1830                                         write!(w, "let mut local_{}{} = ", ident, if !to_c && needs_ref_map {"_base"} else { "" }).unwrap();
1831                                         if prefix_location == ContainerPrefixLocation::OutsideConv {
1832                                                 var_prefix(w, $args_iter().next().unwrap(), generics, is_ref, ptr_for_ref, true);
1833                                         }
1834                                         write!(w, "{}{}", prefix, var).unwrap();
1835
1836                                         for ((pfx, var_name), (idx, ty)) in conversions.iter().zip($args_iter().enumerate()) {
1837                                                 let mut var = std::io::Cursor::new(Vec::new());
1838                                                 write!(&mut var, "{}", var_name).unwrap();
1839                                                 let var_access = String::from_utf8(var.into_inner()).unwrap();
1840
1841                                                 let conv_ty = if needs_ref_map { only_contained_type.as_ref().unwrap() } else { ty };
1842
1843                                                 write!(w, "{} {{ ", pfx).unwrap();
1844                                                 let new_var_name = format!("{}_{}", ident, idx);
1845                                                 let new_var = self.write_conversion_new_var_intern(w, &syn::Ident::new(&new_var_name, Span::call_site()),
1846                                                                 &var_access, conv_ty, generics, contains_slice || (is_ref && ty_has_inner), ptr_for_ref, to_c, path_lookup, container_lookup, var_prefix, var_suffix);
1847                                                 if new_var { write!(w, " ").unwrap(); }
1848
1849                                                 if prefix_location == ContainerPrefixLocation::PerConv {
1850                                                         var_prefix(w, conv_ty, generics, is_ref && ty_has_inner, ptr_for_ref, false);
1851                                                 } else if !is_ref && !needs_ref_map && to_c && only_contained_has_inner {
1852                                                         write!(w, "Box::into_raw(Box::new(").unwrap();
1853                                                 }
1854
1855                                                 write!(w, "{}{}", if contains_slice { "local_" } else { "" }, if new_var { new_var_name } else { var_access }).unwrap();
1856                                                 if prefix_location == ContainerPrefixLocation::PerConv {
1857                                                         var_suffix(w, conv_ty, generics, is_ref && ty_has_inner, ptr_for_ref, false);
1858                                                 } else if !is_ref && !needs_ref_map && to_c && only_contained_has_inner {
1859                                                         write!(w, "))").unwrap();
1860                                                 }
1861                                                 write!(w, " }}").unwrap();
1862                                         }
1863                                         write!(w, "{}", suffix).unwrap();
1864                                         if prefix_location == ContainerPrefixLocation::OutsideConv {
1865                                                 var_suffix(w, $args_iter().next().unwrap(), generics, is_ref, ptr_for_ref, true);
1866                                         }
1867                                         write!(w, ";").unwrap();
1868                                         if !to_c && needs_ref_map {
1869                                                 write!(w, " let mut local_{} = local_{}_base.as_ref()", ident, ident).unwrap();
1870                                                 if contains_slice {
1871                                                         write!(w, ".map(|a| &a[..])").unwrap();
1872                                                 }
1873                                                 write!(w, ";").unwrap();
1874                                         }
1875                                         return true;
1876                                 }
1877                         } }
1878                 }
1879
1880                 match t {
1881                         syn::Type::Reference(r) => {
1882                                 if let syn::Type::Slice(_) = &*r.elem {
1883                                         self.write_conversion_new_var_intern(w, ident, var, &*r.elem, generics, is_ref, ptr_for_ref, to_c, path_lookup, container_lookup, var_prefix, var_suffix)
1884                                 } else {
1885                                         self.write_conversion_new_var_intern(w, ident, var, &*r.elem, generics, true, ptr_for_ref, to_c, path_lookup, container_lookup, var_prefix, var_suffix)
1886                                 }
1887                         },
1888                         syn::Type::Path(p) => {
1889                                 if p.qself.is_some() {
1890                                         unimplemented!();
1891                                 }
1892                                 let resolved_path = self.resolve_path(&p.path, generics);
1893                                 if let Some(aliased_type) = self.crate_types.type_aliases.get(&resolved_path) {
1894                                         return self.write_conversion_new_var_intern(w, ident, var, aliased_type, None, is_ref, ptr_for_ref, to_c, path_lookup, container_lookup, var_prefix, var_suffix);
1895                                 }
1896                                 if self.is_known_container(&resolved_path, is_ref) || self.is_path_transparent_container(&p.path, generics, is_ref) {
1897                                         if let syn::PathArguments::AngleBracketed(args) = &p.path.segments.iter().next().unwrap().arguments {
1898                                                 convert_container!(resolved_path, args.args.len(), || args.args.iter().map(|arg| {
1899                                                         if let syn::GenericArgument::Type(ty) = arg {
1900                                                                 ty
1901                                                         } else { unimplemented!(); }
1902                                                 }));
1903                                         } else { unimplemented!(); }
1904                                 }
1905                                 if self.is_primitive(&resolved_path) {
1906                                         false
1907                                 } else if let Some(ty_ident) = single_ident_generic_path_to_ident(&p.path) {
1908                                         if let Some((prefix, suffix)) = path_lookup(&resolved_path, is_ref) {
1909                                                 write!(w, "let mut local_{} = {}{}{};", ident, prefix, var, suffix).unwrap();
1910                                                 true
1911                                         } else if self.types.maybe_resolve_declared(ty_ident).is_some() {
1912                                                 false
1913                                         } else { false }
1914                                 } else { false }
1915                         },
1916                         syn::Type::Array(_) => {
1917                                 // We assume all arrays contain only primitive types.
1918                                 // This may result in some outputs not compiling.
1919                                 false
1920                         },
1921                         syn::Type::Slice(s) => {
1922                                 if let syn::Type::Path(p) = &*s.elem {
1923                                         let resolved = self.resolve_path(&p.path, generics);
1924                                         assert!(self.is_primitive(&resolved));
1925                                         let slice_path = format!("[{}]", resolved);
1926                                         if let Some((prefix, suffix)) = path_lookup(&slice_path, true) {
1927                                                 write!(w, "let mut local_{} = {}{}{};", ident, prefix, var, suffix).unwrap();
1928                                                 true
1929                                         } else { false }
1930                                 } else if let syn::Type::Reference(ty) = &*s.elem {
1931                                         let tyref = [&*ty.elem];
1932                                         is_ref = true;
1933                                         convert_container!("Slice", 1, || tyref.iter().map(|t| *t));
1934                                         unimplemented!("convert_container should return true as container_lookup should succeed for slices");
1935                                 } else if let syn::Type::Tuple(t) = &*s.elem {
1936                                         // When mapping into a temporary new var, we need to own all the underlying objects.
1937                                         // Thus, we drop any references inside the tuple and convert with non-reference types.
1938                                         let mut elems = syn::punctuated::Punctuated::new();
1939                                         for elem in t.elems.iter() {
1940                                                 if let syn::Type::Reference(r) = elem {
1941                                                         elems.push((*r.elem).clone());
1942                                                 } else {
1943                                                         elems.push(elem.clone());
1944                                                 }
1945                                         }
1946                                         let ty = [syn::Type::Tuple(syn::TypeTuple {
1947                                                 paren_token: t.paren_token, elems
1948                                         })];
1949                                         is_ref = false;
1950                                         ptr_for_ref = true;
1951                                         convert_container!("Slice", 1, || ty.iter());
1952                                         unimplemented!("convert_container should return true as container_lookup should succeed for slices");
1953                                 } else { unimplemented!() }
1954                         },
1955                         syn::Type::Tuple(t) => {
1956                                 if !t.elems.is_empty() {
1957                                         // We don't (yet) support tuple elements which cannot be converted inline
1958                                         write!(w, "let (").unwrap();
1959                                         for idx in 0..t.elems.len() {
1960                                                 if idx != 0 { write!(w, ", ").unwrap(); }
1961                                                 write!(w, "{} orig_{}_{}", if is_ref { "ref" } else { "mut" }, ident, idx).unwrap();
1962                                         }
1963                                         write!(w, ") = {}{}; ", var, if !to_c { ".to_rust()" } else { "" }).unwrap();
1964                                         // Like other template types, tuples are always mapped as their non-ref
1965                                         // versions for types which have different ref mappings. Thus, we convert to
1966                                         // non-ref versions and handle opaque types with inner pointers manually.
1967                                         for (idx, elem) in t.elems.iter().enumerate() {
1968                                                 if let syn::Type::Path(p) = elem {
1969                                                         let v_name = format!("orig_{}_{}", ident, idx);
1970                                                         let tuple_elem_ident = syn::Ident::new(&v_name, Span::call_site());
1971                                                         if self.write_conversion_new_var_intern(w, &tuple_elem_ident, &v_name, elem, generics,
1972                                                                         false, ptr_for_ref, to_c,
1973                                                                         path_lookup, container_lookup, var_prefix, var_suffix) {
1974                                                                 write!(w, " ").unwrap();
1975                                                                 // Opaque types with inner pointers shouldn't ever create new stack
1976                                                                 // variables, so we don't handle it and just assert that it doesn't
1977                                                                 // here.
1978                                                                 assert!(!self.c_type_has_inner_from_path(&self.resolve_path(&p.path, generics)));
1979                                                         }
1980                                                 }
1981                                         }
1982                                         write!(w, "let mut local_{} = (", ident).unwrap();
1983                                         for (idx, elem) in t.elems.iter().enumerate() {
1984                                                 let ty_has_inner = {
1985                                                                 if to_c {
1986                                                                         // "To C ptr_for_ref" means "return the regular object with
1987                                                                         // is_owned set to false", which is totally what we want
1988                                                                         // if we're about to set ty_has_inner.
1989                                                                         ptr_for_ref = true;
1990                                                                 }
1991                                                                 if let syn::Type::Reference(t) = elem {
1992                                                                         if let syn::Type::Path(p) = &*t.elem {
1993                                                                                 self.c_type_has_inner_from_path(&self.resolve_path(&p.path, generics))
1994                                                                         } else { false }
1995                                                                 } else if let syn::Type::Path(p) = elem {
1996                                                                         self.c_type_has_inner_from_path(&self.resolve_path(&p.path, generics))
1997                                                                 } else { false }
1998                                                         };
1999                                                 if idx != 0 { write!(w, ", ").unwrap(); }
2000                                                 var_prefix(w, elem, generics, is_ref && ty_has_inner, ptr_for_ref, false);
2001                                                 if is_ref && ty_has_inner {
2002                                                         // For ty_has_inner, the regular var_prefix mapping will take a
2003                                                         // reference, so deref once here to make sure we keep the original ref.
2004                                                         write!(w, "*").unwrap();
2005                                                 }
2006                                                 write!(w, "orig_{}_{}", ident, idx).unwrap();
2007                                                 if is_ref && !ty_has_inner {
2008                                                         // If we don't have an inner variable's reference to maintain, just
2009                                                         // hope the type is Clonable and use that.
2010                                                         write!(w, ".clone()").unwrap();
2011                                                 }
2012                                                 var_suffix(w, elem, generics, is_ref && ty_has_inner, ptr_for_ref, false);
2013                                         }
2014                                         write!(w, "){};", if to_c { ".into()" } else { "" }).unwrap();
2015                                         true
2016                                 } else { false }
2017                         },
2018                         _ => unimplemented!(),
2019                 }
2020         }
2021
2022         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) -> bool {
2023                 self.write_conversion_new_var_intern(w, ident, var_access, t, generics, false, ptr_for_ref, true,
2024                         &|a, b| self.to_c_conversion_new_var_from_path(a, b),
2025                         &|a, b, c, d, e| self.to_c_conversion_container_new_var(generics, a, b, c, d, e),
2026                         // We force ptr_for_ref here since we can't generate a ref on one line and use it later
2027                         &|a, b, c, d, e, f| self.write_to_c_conversion_inline_prefix_inner(a, b, c, d, e, f),
2028                         &|a, b, c, d, e, f| self.write_to_c_conversion_inline_suffix_inner(a, b, c, d, e, f))
2029         }
2030         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 {
2031                 self.write_to_c_conversion_new_var_inner(w, ident, &format!("{}", ident), t, generics, ptr_for_ref)
2032         }
2033         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 {
2034                 self.write_conversion_new_var_intern(w, ident, &format!("{}", ident), t, generics, false, false, false,
2035                         &|a, b| self.from_c_conversion_new_var_from_path(a, b),
2036                         &|a, b, c, d, e| self.from_c_conversion_container_new_var(generics, a, b, c, d, e),
2037                         // We force ptr_for_ref here since we can't generate a ref on one line and use it later
2038                         &|a, b, c, d, e, _f| self.write_from_c_conversion_prefix_inner(a, b, c, d, e),
2039                         &|a, b, c, d, e, _f| self.write_from_c_conversion_suffix_inner(a, b, c, d, e))
2040         }
2041
2042         // ******************************************************
2043         // *** C Container Type Equivalent and alias Printing ***
2044         // ******************************************************
2045
2046         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 {
2047                 for (idx, t) in args.enumerate() {
2048                         if idx != 0 {
2049                                 write!(w, ", ").unwrap();
2050                         }
2051                         if let syn::Type::Reference(r_arg) = t {
2052                                 assert!(!is_ref); // We don't currently support outer reference types for non-primitive inners
2053
2054                                 if !self.write_c_type_intern(w, &*r_arg.elem, generics, false, false, false) { return false; }
2055
2056                                 // While write_c_type_intern, above is correct, we don't want to blindly convert a
2057                                 // reference to something stupid, so check that the container is either opaque or a
2058                                 // predefined type (currently only Transaction).
2059                                 if let syn::Type::Path(p_arg) = &*r_arg.elem {
2060                                         let resolved = self.resolve_path(&p_arg.path, generics);
2061                                         assert!(self.crate_types.opaques.get(&resolved).is_some() ||
2062                                                         self.c_type_from_path(&resolved, true, true).is_some(), "Template generics should be opaque or have a predefined mapping");
2063                                 } else { unimplemented!(); }
2064                         } else if let syn::Type::Path(p_arg) = t {
2065                                 if let Some(resolved) = self.maybe_resolve_path(&p_arg.path, generics) {
2066                                         if !self.is_primitive(&resolved) {
2067                                                 assert!(!is_ref); // We don't currently support outer reference types for non-primitive inners
2068                                         }
2069                                 } else {
2070                                         assert!(!is_ref); // We don't currently support outer reference types for non-primitive inners
2071                                 }
2072                                 if !self.write_c_type_intern(w, t, generics, false, false, false) { return false; }
2073                         } else {
2074                                 assert!(!is_ref); // We don't currently support outer reference types for non-primitive inners
2075                                 if !self.write_c_type_intern(w, t, generics, false, false, false) { return false; }
2076                         }
2077                 }
2078                 true
2079         }
2080         fn check_create_container(&self, mangled_container: String, container_type: &str, args: Vec<&syn::Type>, generics: Option<&GenericTypes>, is_ref: bool) -> bool {
2081                 if !self.crate_types.templates_defined.borrow().get(&mangled_container).is_some() {
2082                         let mut created_container: Vec<u8> = Vec::new();
2083
2084                         if container_type == "Result" {
2085                                 let mut a_ty: Vec<u8> = Vec::new();
2086                                 if let syn::Type::Tuple(tup) = args.iter().next().unwrap() {
2087                                         if tup.elems.is_empty() {
2088                                                 write!(&mut a_ty, "()").unwrap();
2089                                         } else {
2090                                                 if !self.write_template_generics(&mut a_ty, &mut args.iter().map(|t| *t).take(1), generics, is_ref) { return false; }
2091                                         }
2092                                 } else {
2093                                         if !self.write_template_generics(&mut a_ty, &mut args.iter().map(|t| *t).take(1), generics, is_ref) { return false; }
2094                                 }
2095
2096                                 let mut b_ty: Vec<u8> = Vec::new();
2097                                 if let syn::Type::Tuple(tup) = args.iter().skip(1).next().unwrap() {
2098                                         if tup.elems.is_empty() {
2099                                                 write!(&mut b_ty, "()").unwrap();
2100                                         } else {
2101                                                 if !self.write_template_generics(&mut b_ty, &mut args.iter().map(|t| *t).skip(1), generics, is_ref) { return false; }
2102                                         }
2103                                 } else {
2104                                         if !self.write_template_generics(&mut b_ty, &mut args.iter().map(|t| *t).skip(1), generics, is_ref) { return false; }
2105                                 }
2106
2107                                 let ok_str = String::from_utf8(a_ty).unwrap();
2108                                 let err_str = String::from_utf8(b_ty).unwrap();
2109                                 let is_clonable = self.is_clonable(&ok_str) && self.is_clonable(&err_str);
2110                                 write_result_block(&mut created_container, &mangled_container, &ok_str, &err_str, is_clonable);
2111                                 if is_clonable {
2112                                         self.crate_types.set_clonable(Self::generated_container_path().to_owned() + "::" + &mangled_container);
2113                                 }
2114                         } else if container_type == "Vec" {
2115                                 let mut a_ty: Vec<u8> = Vec::new();
2116                                 if !self.write_template_generics(&mut a_ty, &mut args.iter().map(|t| *t), generics, is_ref) { return false; }
2117                                 let ty = String::from_utf8(a_ty).unwrap();
2118                                 let is_clonable = self.is_clonable(&ty);
2119                                 write_vec_block(&mut created_container, &mangled_container, &ty, is_clonable);
2120                                 if is_clonable {
2121                                         self.crate_types.set_clonable(Self::generated_container_path().to_owned() + "::" + &mangled_container);
2122                                 }
2123                         } else if container_type.ends_with("Tuple") {
2124                                 let mut tuple_args = Vec::new();
2125                                 let mut is_clonable = true;
2126                                 for arg in args.iter() {
2127                                         let mut ty: Vec<u8> = Vec::new();
2128                                         if !self.write_template_generics(&mut ty, &mut [arg].iter().map(|t| **t), generics, is_ref) { return false; }
2129                                         let ty_str = String::from_utf8(ty).unwrap();
2130                                         if !self.is_clonable(&ty_str) {
2131                                                 is_clonable = false;
2132                                         }
2133                                         tuple_args.push(ty_str);
2134                                 }
2135                                 write_tuple_block(&mut created_container, &mangled_container, &tuple_args, is_clonable);
2136                                 if is_clonable {
2137                                         self.crate_types.set_clonable(Self::generated_container_path().to_owned() + "::" + &mangled_container);
2138                                 }
2139                         } else if container_type == "Option" {
2140                                 let mut a_ty: Vec<u8> = Vec::new();
2141                                 if !self.write_template_generics(&mut a_ty, &mut args.iter().map(|t| *t), generics, is_ref) { return false; }
2142                                 let ty = String::from_utf8(a_ty).unwrap();
2143                                 let is_clonable = self.is_clonable(&ty);
2144                                 write_option_block(&mut created_container, &mangled_container, &ty, is_clonable);
2145                                 if is_clonable {
2146                                         self.crate_types.set_clonable(Self::generated_container_path().to_owned() + "::" + &mangled_container);
2147                                 }
2148                         } else {
2149                                 unreachable!();
2150                         }
2151                         self.crate_types.write_new_template(mangled_container.clone(), true, &created_container);
2152                 }
2153                 true
2154         }
2155         fn path_to_generic_args(path: &syn::Path) -> Vec<&syn::Type> {
2156                 if let syn::PathArguments::AngleBracketed(args) = &path.segments.iter().next().unwrap().arguments {
2157                         args.args.iter().map(|gen| if let syn::GenericArgument::Type(t) = gen { t } else { unimplemented!() }).collect()
2158                 } else { unimplemented!(); }
2159         }
2160         fn write_c_mangled_container_path_intern<W: std::io::Write>
2161                         (&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 {
2162                 let mut mangled_type: Vec<u8> = Vec::new();
2163                 if !self.is_transparent_container(ident, is_ref, args.iter().map(|a| *a)) {
2164                         write!(w, "C{}_", ident).unwrap();
2165                         write!(mangled_type, "C{}_", ident).unwrap();
2166                 } else { assert_eq!(args.len(), 1); }
2167                 for arg in args.iter() {
2168                         macro_rules! write_path {
2169                                 ($p_arg: expr, $extra_write: expr) => {
2170                                         if let Some(subtype) = self.maybe_resolve_path(&$p_arg.path, generics) {
2171                                                 if self.is_transparent_container(ident, is_ref, args.iter().map(|a| *a)) {
2172                                                         if !in_type {
2173                                                                 if self.c_type_has_inner_from_path(&subtype) {
2174                                                                         if !self.write_c_path_intern(w, &$p_arg.path, generics, is_ref, is_mut, ptr_for_ref) { return false; }
2175                                                                 } else {
2176                                                                         if let Some(arr_ty) = self.is_real_type_array(&subtype) {
2177                                                                                 if !self.write_c_type_intern(w, &arr_ty, generics, false, true, false) { return false; }
2178                                                                         } else {
2179                                                                                 // Option<T> needs to be converted to a *mut T, ie mut ptr-for-ref
2180                                                                                 if !self.write_c_path_intern(w, &$p_arg.path, generics, true, true, true) { return false; }
2181                                                                         }
2182                                                                 }
2183                                                         } else {
2184                                                                 write!(w, "{}", $p_arg.path.segments.last().unwrap().ident).unwrap();
2185                                                         }
2186                                                 } else if self.is_known_container(&subtype, is_ref) || self.is_path_transparent_container(&$p_arg.path, generics, is_ref) {
2187                                                         if !self.write_c_mangled_container_path_intern(w, Self::path_to_generic_args(&$p_arg.path), generics,
2188                                                                         &subtype, is_ref, is_mut, ptr_for_ref, true) {
2189                                                                 return false;
2190                                                         }
2191                                                         self.write_c_mangled_container_path_intern(&mut mangled_type, Self::path_to_generic_args(&$p_arg.path),
2192                                                                 generics, &subtype, is_ref, is_mut, ptr_for_ref, true);
2193                                                         if let Some(w2) = $extra_write as Option<&mut Vec<u8>> {
2194                                                                 self.write_c_mangled_container_path_intern(w2, Self::path_to_generic_args(&$p_arg.path),
2195                                                                         generics, &subtype, is_ref, is_mut, ptr_for_ref, true);
2196                                                         }
2197                                                 } else {
2198                                                         let id = subtype.rsplitn(2, ':').next().unwrap(); // Get the "Base" name of the resolved type
2199                                                         write!(w, "{}", id).unwrap();
2200                                                         write!(mangled_type, "{}", id).unwrap();
2201                                                         if let Some(w2) = $extra_write as Option<&mut Vec<u8>> {
2202                                                                 write!(w2, "{}", id).unwrap();
2203                                                         }
2204                                                 }
2205                                         } else { return false; }
2206                                 }
2207                         }
2208                         if let syn::Type::Tuple(tuple) = arg {
2209                                 if tuple.elems.len() == 0 {
2210                                         write!(w, "None").unwrap();
2211                                         write!(mangled_type, "None").unwrap();
2212                                 } else {
2213                                         let mut mangled_tuple_type: Vec<u8> = Vec::new();
2214
2215                                         // Figure out what the mangled type should look like. To disambiguate
2216                                         // ((A, B), C) and (A, B, C) we prefix the generic args with a _ and suffix
2217                                         // them with a Z. Ideally we wouldn't use Z, but not many special chars are
2218                                         // available for use in type names.
2219                                         write!(w, "C{}Tuple_", tuple.elems.len()).unwrap();
2220                                         write!(mangled_type, "C{}Tuple_", tuple.elems.len()).unwrap();
2221                                         write!(mangled_tuple_type, "C{}Tuple_", tuple.elems.len()).unwrap();
2222                                         for elem in tuple.elems.iter() {
2223                                                 if let syn::Type::Path(p) = elem {
2224                                                         write_path!(p, Some(&mut mangled_tuple_type));
2225                                                 } else if let syn::Type::Reference(refelem) = elem {
2226                                                         if let syn::Type::Path(p) = &*refelem.elem {
2227                                                                 write_path!(p, Some(&mut mangled_tuple_type));
2228                                                         } else { return false; }
2229                                                 } else { return false; }
2230                                         }
2231                                         write!(w, "Z").unwrap();
2232                                         write!(mangled_type, "Z").unwrap();
2233                                         write!(mangled_tuple_type, "Z").unwrap();
2234                                         if !self.check_create_container(String::from_utf8(mangled_tuple_type).unwrap(),
2235                                                         &format!("{}Tuple", tuple.elems.len()), tuple.elems.iter().collect(), generics, is_ref) {
2236                                                 return false;
2237                                         }
2238                                 }
2239                         } else if let syn::Type::Path(p_arg) = arg {
2240                                 write_path!(p_arg, None);
2241                         } else if let syn::Type::Reference(refty) = arg {
2242                                 if let syn::Type::Path(p_arg) = &*refty.elem {
2243                                         write_path!(p_arg, None);
2244                                 } else if let syn::Type::Slice(_) = &*refty.elem {
2245                                         // write_c_type will actually do exactly what we want here, we just need to
2246                                         // make it a pointer so that its an option. Note that we cannot always convert
2247                                         // the Vec-as-slice (ie non-ref types) containers, so sometimes need to be able
2248                                         // to edit it, hence we use *mut here instead of *const.
2249                                         if args.len() != 1 { return false; }
2250                                         write!(w, "*mut ").unwrap();
2251                                         self.write_c_type(w, arg, None, true);
2252                                 } else { return false; }
2253                         } else if let syn::Type::Array(a) = arg {
2254                                 if let syn::Type::Path(p_arg) = &*a.elem {
2255                                         let resolved = self.resolve_path(&p_arg.path, generics);
2256                                         if !self.is_primitive(&resolved) { return false; }
2257                                         if let syn::Expr::Lit(syn::ExprLit { lit: syn::Lit::Int(len), .. }) = &a.len {
2258                                                 if self.c_type_from_path(&format!("[{}; {}]", resolved, len.base10_digits()), is_ref, ptr_for_ref).is_none() { return false; }
2259                                                 write!(w, "_{}{}", resolved, len.base10_digits()).unwrap();
2260                                                 write!(mangled_type, "_{}{}", resolved, len.base10_digits()).unwrap();
2261                                         } else { return false; }
2262                                 } else { return false; }
2263                         } else { return false; }
2264                 }
2265                 if self.is_transparent_container(ident, is_ref, args.iter().map(|a| *a)) { return true; }
2266                 // Push the "end of type" Z
2267                 write!(w, "Z").unwrap();
2268                 write!(mangled_type, "Z").unwrap();
2269
2270                 // Make sure the type is actually defined:
2271                 self.check_create_container(String::from_utf8(mangled_type).unwrap(), ident, args, generics, is_ref)
2272         }
2273         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 {
2274                 if !self.is_transparent_container(ident, is_ref, args.iter().map(|a| *a)) {
2275                         write!(w, "{}::", Self::generated_container_path()).unwrap();
2276                 }
2277                 self.write_c_mangled_container_path_intern(w, args, generics, ident, is_ref, is_mut, ptr_for_ref, false)
2278         }
2279
2280         // **********************************
2281         // *** C Type Equivalent Printing ***
2282         // **********************************
2283
2284         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) -> bool {
2285                 let full_path = match self.maybe_resolve_path(&path, generics) {
2286                         Some(path) => path, None => return false };
2287                 if let Some(c_type) = self.c_type_from_path(&full_path, is_ref, ptr_for_ref) {
2288                         write!(w, "{}", c_type).unwrap();
2289                         true
2290                 } else if self.crate_types.traits.get(&full_path).is_some() {
2291                         if is_ref && ptr_for_ref {
2292                                 write!(w, "*{} crate::{}", if is_mut { "mut" } else { "const" }, full_path).unwrap();
2293                         } else if is_ref {
2294                                 write!(w, "&{}crate::{}", if is_mut { "mut " } else { "" }, full_path).unwrap();
2295                         } else {
2296                                 write!(w, "crate::{}", full_path).unwrap();
2297                         }
2298                         true
2299                 } else if self.crate_types.opaques.get(&full_path).is_some() || self.crate_types.mirrored_enums.get(&full_path).is_some() {
2300                         if is_ref && ptr_for_ref {
2301                                 // ptr_for_ref implies we're returning the object, which we can't really do for
2302                                 // opaque or mirrored types without box'ing them, which is quite a waste, so return
2303                                 // the actual object itself (for opaque types we'll set the pointer to the actual
2304                                 // type and note that its a reference).
2305                                 write!(w, "crate::{}", full_path).unwrap();
2306                         } else if is_ref {
2307                                 write!(w, "&{}crate::{}", if is_mut { "mut " } else { "" }, full_path).unwrap();
2308                         } else {
2309                                 write!(w, "crate::{}", full_path).unwrap();
2310                         }
2311                         true
2312                 } else {
2313                         false
2314                 }
2315         }
2316         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) -> bool {
2317                 match t {
2318                         syn::Type::Path(p) => {
2319                                 if p.qself.is_some() {
2320                                         return false;
2321                                 }
2322                                 if let Some(full_path) = self.maybe_resolve_path(&p.path, generics) {
2323                                         if self.is_known_container(&full_path, is_ref) || self.is_path_transparent_container(&p.path, generics, is_ref) {
2324                                                 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);
2325                                         }
2326                                         if let Some(aliased_type) = self.crate_types.type_aliases.get(&full_path).cloned() {
2327                                                 return self.write_c_type_intern(w, &aliased_type, None, is_ref, is_mut, ptr_for_ref);
2328                                         }
2329                                 }
2330                                 self.write_c_path_intern(w, &p.path, generics, is_ref, is_mut, ptr_for_ref)
2331                         },
2332                         syn::Type::Reference(r) => {
2333                                 self.write_c_type_intern(w, &*r.elem, generics, true, r.mutability.is_some(), ptr_for_ref)
2334                         },
2335                         syn::Type::Array(a) => {
2336                                 if is_ref && is_mut {
2337                                         write!(w, "*mut [").unwrap();
2338                                         if !self.write_c_type_intern(w, &a.elem, generics, false, false, ptr_for_ref) { return false; }
2339                                 } else if is_ref {
2340                                         write!(w, "*const [").unwrap();
2341                                         if !self.write_c_type_intern(w, &a.elem, generics, false, false, ptr_for_ref) { return false; }
2342                                 } else {
2343                                         let mut typecheck = Vec::new();
2344                                         if !self.write_c_type_intern(&mut typecheck, &a.elem, generics, false, false, ptr_for_ref) { return false; }
2345                                         if typecheck[..] != ['u' as u8, '8' as u8] { return false; }
2346                                 }
2347                                 if let syn::Expr::Lit(l) = &a.len {
2348                                         if let syn::Lit::Int(i) = &l.lit {
2349                                                 if !is_ref {
2350                                                         if let Some(ty) = self.c_type_from_path(&format!("[u8; {}]", i.base10_digits()), false, ptr_for_ref) {
2351                                                                 write!(w, "{}", ty).unwrap();
2352                                                                 true
2353                                                         } else { false }
2354                                                 } else {
2355                                                         write!(w, "; {}]", i).unwrap();
2356                                                         true
2357                                                 }
2358                                         } else { false }
2359                                 } else { false }
2360                         }
2361                         syn::Type::Slice(s) => {
2362                                 if !is_ref || is_mut { return false; }
2363                                 if let syn::Type::Path(p) = &*s.elem {
2364                                         let resolved = self.resolve_path(&p.path, generics);
2365                                         if self.is_primitive(&resolved) {
2366                                                 write!(w, "{}::{}slice", Self::container_templ_path(), resolved).unwrap();
2367                                                 true
2368                                         } else { false }
2369                                 } else if let syn::Type::Reference(r) = &*s.elem {
2370                                         if let syn::Type::Path(p) = &*r.elem {
2371                                                 // Slices with "real types" inside are mapped as the equivalent non-ref Vec
2372                                                 let resolved = self.resolve_path(&p.path, generics);
2373                                                 let mangled_container = if let Some(ident) = self.crate_types.opaques.get(&resolved) {
2374                                                         format!("CVec_{}Z", ident)
2375                                                 } else if let Some(en) = self.crate_types.mirrored_enums.get(&resolved) {
2376                                                         format!("CVec_{}Z", en.ident)
2377                                                 } else if let Some(id) = p.path.get_ident() {
2378                                                         format!("CVec_{}Z", id)
2379                                                 } else { return false; };
2380                                                 write!(w, "{}::{}", Self::generated_container_path(), mangled_container).unwrap();
2381                                                 self.check_create_container(mangled_container, "Vec", vec![&*r.elem], generics, false)
2382                                         } else { false }
2383                                 } else if let syn::Type::Tuple(_) = &*s.elem {
2384                                         let mut args = syn::punctuated::Punctuated::new();
2385                                         args.push(syn::GenericArgument::Type((*s.elem).clone()));
2386                                         let mut segments = syn::punctuated::Punctuated::new();
2387                                         segments.push(syn::PathSegment {
2388                                                 ident: syn::Ident::new("Vec", Span::call_site()),
2389                                                 arguments: syn::PathArguments::AngleBracketed(syn::AngleBracketedGenericArguments {
2390                                                         colon2_token: None, lt_token: syn::Token![<](Span::call_site()), args, gt_token: syn::Token![>](Span::call_site()),
2391                                                 })
2392                                         });
2393                                         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)
2394                                 } else { false }
2395                         },
2396                         syn::Type::Tuple(t) => {
2397                                 if t.elems.len() == 0 {
2398                                         true
2399                                 } else {
2400                                         self.write_c_mangled_container_path(w, t.elems.iter().collect(), generics,
2401                                                 &format!("{}Tuple", t.elems.len()), is_ref, is_mut, ptr_for_ref)
2402                                 }
2403                         },
2404                         _ => false,
2405                 }
2406         }
2407         pub fn write_c_type<W: std::io::Write>(&self, w: &mut W, t: &syn::Type, generics: Option<&GenericTypes>, ptr_for_ref: bool) {
2408                 assert!(self.write_c_type_intern(w, t, generics, false, false, ptr_for_ref));
2409         }
2410         pub fn understood_c_path(&self, p: &syn::Path) -> bool {
2411                 if p.leading_colon.is_some() { return false; }
2412                 self.write_c_path_intern(&mut std::io::sink(), p, None, false, false, false)
2413         }
2414         pub fn understood_c_type(&self, t: &syn::Type, generics: Option<&GenericTypes>) -> bool {
2415                 self.write_c_type_intern(&mut std::io::sink(), t, generics, false, false, false)
2416         }
2417 }