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

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