_ 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 /// Top-level struct tracking everything which has been defined while walking the crate.
 631 pub struct CrateTypes<'a> {
 632         /// This may contain structs or enums, but only when either is mapped as
 633         /// struct X { inner: *mut originalX, .. }
 634         pub opaques: HashMap<String, &'a syn::Ident>,
 635         /// Enums which are mapped as C enums with conversion functions
 636         pub mirrored_enums: HashMap<String, &'a syn::ItemEnum>,
 637         /// Traits which are mapped as a pointer + jump table
 638         pub traits: HashMap<String, &'a syn::ItemTrait>,
 639         /// Aliases from paths to some other Type
 640         pub type_aliases: HashMap<String, syn::Type>,
 641         /// Value is an alias to Key (maybe with some generics)
 642         pub reverse_alias_map: HashMap<String, Vec<(syn::Path, syn::PathArguments)>>,
 643         /// Template continer types defined, map from mangled type name -> whether a destructor fn
 644         /// exists.
 645         ///
 646         /// This is used at the end of processing to make C++ wrapper classes
 647         pub templates_defined: RefCell<HashMap<String, bool, NonRandomHash>>,
 648         /// The output file for any created template container types, written to as we find new
 649         /// template containers which need to be defined.
 650         template_file: RefCell<&'a mut File>,
 651         /// Set of containers which are clonable
 652         clonable_types: RefCell<HashSet<String>>,
 653         /// Key impls Value
 654         pub trait_impls: HashMap<String, Vec<String>>,
 655         /// The full set of modules in the crate(s)
 656         pub lib_ast: &'a FullLibraryAST,
 657 }
 658
 659 impl<'a> CrateTypes<'a> {
 660         pub fn new(template_file: &'a mut File, libast: &'a FullLibraryAST) -> Self {
 661                 CrateTypes {
 662                         opaques: HashMap::new(), mirrored_enums: HashMap::new(), traits: HashMap::new(),
 663                         type_aliases: HashMap::new(), reverse_alias_map: HashMap::new(),
 664                         templates_defined: RefCell::new(HashMap::default()),
 665                         clonable_types: RefCell::new(HashSet::new()), trait_impls: HashMap::new(),
 666                         template_file: RefCell::new(template_file), lib_ast: &libast,
 667                 }
 668         }
 669         pub fn set_clonable(&self, object: String) {
 670                 self.clonable_types.borrow_mut().insert(object);
 671         }
 672         pub fn is_clonable(&self, object: &str) -> bool {
 673                 self.clonable_types.borrow().contains(object)
 674         }
 675         pub fn write_new_template(&self, mangled_container: String, has_destructor: bool, created_container: &[u8]) {
 676                 self.template_file.borrow_mut().write(created_container).unwrap();
 677                 self.templates_defined.borrow_mut().insert(mangled_container, has_destructor);
 678         }
 679 }
 680
 681 /// A struct which tracks resolving rust types into C-mapped equivalents, exists for one specific
 682 /// module but contains a reference to the overall CrateTypes tracking.
 683 pub struct TypeResolver<'mod_lifetime, 'crate_lft: 'mod_lifetime> {
 684         pub module_path: &'mod_lifetime str,
 685         pub crate_types: &'mod_lifetime CrateTypes<'crate_lft>,
 686         types: ImportResolver<'mod_lifetime, 'crate_lft>,
 687 }
 688
 689 /// Returned by write_empty_rust_val_check_suffix to indicate what type of dereferencing needs to
 690 /// happen to get the inner value of a generic.
 691 enum EmptyValExpectedTy {
 692         /// A type which has a flag for being empty (eg an array where we treat all-0s as empty).
 693         NonPointer,
 694         /// A pointer that we want to dereference and move out of.
 695         OwnedPointer,
 696         /// A pointer which we want to convert to a reference.
 697         ReferenceAsPointer,
 698 }
 699
 700 #[derive(PartialEq)]
 701 /// Describes the appropriate place to print a general type-conversion string when converting a
 702 /// container.
 703 enum ContainerPrefixLocation {
 704         /// Prints a general type-conversion string prefix and suffix outside of the
 705         /// container-conversion strings.
 706         OutsideConv,
 707         /// Prints a general type-conversion string prefix and suffix inside of the
 708         /// container-conversion strings.
 709         PerConv,
 710         /// Does not print the usual type-conversion string prefix and suffix.
 711         NoPrefix,
 712 }
 713
 714 impl<'a, 'c: 'a> TypeResolver<'a, 'c> {
 715         pub fn new(module_path: &'a str, types: ImportResolver<'a, 'c>, crate_types: &'a CrateTypes<'c>) -> Self {
 716                 Self { module_path, types, crate_types }
 717         }
 718
 719         // *************************************************
 720         // *** Well know type and conversion definitions ***
 721         // *************************************************
 722
 723         /// Returns true we if can just skip passing this to C entirely
 724         fn skip_path(&self, full_path: &str) -> bool {
 725                 full_path == "bitcoin::secp256k1::Secp256k1" ||
 726                 full_path == "bitcoin::secp256k1::Signing" ||
 727                 full_path == "bitcoin::secp256k1::Verification"
 728         }
 729         /// Returns true we if can just skip passing this to C entirely
 730         fn no_arg_path_to_rust(&self, full_path: &str) -> &str {
 731                 if full_path == "bitcoin::secp256k1::Secp256k1" {
 732                         "secp256k1::SECP256K1"
 733                 } else { unimplemented!(); }
 734         }
 735
 736         /// Returns true if the object is a primitive and is mapped as-is with no conversion
 737         /// whatsoever.
 738         pub fn is_primitive(&self, full_path: &str) -> bool {
 739                 match full_path {
 740                         "bool" => true,
 741                         "u64" => true,
 742                         "u32" => true,
 743                         "u16" => true,
 744                         "u8" => true,
 745                         "usize" => true,
 746                         _ => false,
 747                 }
 748         }
 749         pub fn is_clonable(&self, ty: &str) -> bool {
 750                 if self.crate_types.is_clonable(ty) { return true; }
 751                 if self.is_primitive(ty) { return true; }
 752                 match ty {
 753                         "()" => true,
 754                         "crate::c_types::Signature" => true,
 755                         "crate::c_types::TxOut" => true,
 756                         _ => false,
 757                 }
 758         }
 759         /// Gets the C-mapped type for types which are outside of the crate, or which are manually
 760         /// ignored by for some reason need mapping anyway.
 761         fn c_type_from_path<'b>(&self, full_path: &'b str, is_ref: bool, _ptr_for_ref: bool) -> Option<&'b str> {
 762                 if self.is_primitive(full_path) {
 763                         return Some(full_path);
 764                 }
 765                 match full_path {
 766                         "Result" => Some("crate::c_types::derived::CResult"),
 767                         "Vec" if !is_ref => Some("crate::c_types::derived::CVec"),
 768                         "Option" => Some(""),
 769
 770                         // Note that no !is_ref types can map to an array because Rust and C's call semantics
 771                         // for arrays are different (https://github.com/eqrion/cbindgen/issues/528)
 772
 773                         "[u8; 32]" if !is_ref => Some("crate::c_types::ThirtyTwoBytes"),
 774                         "[u8; 16]" if !is_ref => Some("crate::c_types::SixteenBytes"),
 775                         "[u8; 10]" if !is_ref => Some("crate::c_types::TenBytes"),
 776                         "[u8; 4]" if !is_ref => Some("crate::c_types::FourBytes"),
 777                         "[u8; 3]" if !is_ref => Some("crate::c_types::ThreeBytes"), // Used for RGB values
 778
 779                         "str" if is_ref => Some("crate::c_types::Str"),
 780                         "String" if !is_ref => Some("crate::c_types::derived::CVec_u8Z"),
 781                         "String" if is_ref => Some("crate::c_types::Str"),
 782
 783                         "std::time::Duration" => Some("u64"),
 784                         "std::io::Error" => Some("crate::c_types::IOError"),
 785
 786                         "bitcoin::secp256k1::key::PublicKey"|"bitcoin::secp256k1::PublicKey"|"secp256k1::key::PublicKey"
 787                                 => Some("crate::c_types::PublicKey"),
 788                         "bitcoin::secp256k1::Signature" => Some("crate::c_types::Signature"),
 789                         "bitcoin::secp256k1::key::SecretKey"|"bitcoin::secp256k1::SecretKey"
 790                                 if is_ref  => Some("*const [u8; 32]"),
 791                         "bitcoin::secp256k1::key::SecretKey"|"bitcoin::secp256k1::SecretKey"
 792                                 if !is_ref => Some("crate::c_types::SecretKey"),
 793                         "bitcoin::secp256k1::Error"|"secp256k1::Error"
 794                                 if !is_ref => Some("crate::c_types::Secp256k1Error"),
 795                         "bitcoin::blockdata::script::Script" if is_ref => Some("crate::c_types::u8slice"),
 796                         "bitcoin::blockdata::script::Script" if !is_ref => Some("crate::c_types::derived::CVec_u8Z"),
 797                         "bitcoin::blockdata::transaction::OutPoint" => Some("crate::lightning::chain::transaction::OutPoint"),
 798                         "bitcoin::blockdata::transaction::Transaction" => Some("crate::c_types::Transaction"),
 799                         "bitcoin::blockdata::transaction::TxOut" if !is_ref => Some("crate::c_types::TxOut"),
 800                         "bitcoin::network::constants::Network" => Some("crate::bitcoin::network::Network"),
 801                         "bitcoin::blockdata::block::BlockHeader" if is_ref  => Some("*const [u8; 80]"),
 802                         "bitcoin::blockdata::block::Block" if is_ref  => Some("crate::c_types::u8slice"),
 803
 804                         // Newtypes that we just expose in their original form.
 805                         "bitcoin::hash_types::Txid"|"bitcoin::hash_types::BlockHash"|"bitcoin_hashes::sha256::Hash"
 806                                 if is_ref  => Some("*const [u8; 32]"),
 807                         "bitcoin::hash_types::Txid"|"bitcoin::hash_types::BlockHash"|"bitcoin_hashes::sha256::Hash"
 808                                 if !is_ref => Some("crate::c_types::ThirtyTwoBytes"),
 809                         "bitcoin::secp256k1::Message" if !is_ref => Some("crate::c_types::ThirtyTwoBytes"),
 810                         "lightning::ln::channelmanager::PaymentHash" if is_ref => Some("*const [u8; 32]"),
 811                         "lightning::ln::channelmanager::PaymentHash" if !is_ref => Some("crate::c_types::ThirtyTwoBytes"),
 812                         "lightning::ln::channelmanager::PaymentPreimage" if is_ref => Some("*const [u8; 32]"),
 813                         "lightning::ln::channelmanager::PaymentPreimage" if !is_ref => Some("crate::c_types::ThirtyTwoBytes"),
 814                         "lightning::ln::channelmanager::PaymentSecret" if is_ref => Some("crate::c_types::ThirtyTwoBytes"),
 815                         "lightning::ln::channelmanager::PaymentSecret" if !is_ref => Some("crate::c_types::ThirtyTwoBytes"),
 816
 817                         // Override the default since Records contain an fmt with a lifetime:
 818                         "lightning::util::logger::Record" => Some("*const std::os::raw::c_char"),
 819
 820                         _ => None,
 821                 }
 822         }
 823
 824         fn from_c_conversion_new_var_from_path<'b>(&self, _full_path: &str, _is_ref: bool) -> Option<(&'b str, &'b str)> {
 825                 None
 826         }
 827         fn from_c_conversion_prefix_from_path<'b>(&self, full_path: &str, is_ref: bool) -> Option<String> {
 828                 if self.is_primitive(full_path) {
 829                         return Some("".to_owned());
 830                 }
 831                 match full_path {
 832                         "Vec" if !is_ref => Some("local_"),
 833                         "Result" if !is_ref => Some("local_"),
 834                         "Option" if is_ref => Some("&local_"),
 835                         "Option" => Some("local_"),
 836
 837                         "[u8; 32]" if is_ref => Some("unsafe { &*"),
 838                         "[u8; 32]" if !is_ref => Some(""),
 839                         "[u8; 16]" if !is_ref => Some(""),
 840                         "[u8; 10]" if !is_ref => Some(""),
 841                         "[u8; 4]" if !is_ref => Some(""),
 842                         "[u8; 3]" if !is_ref => Some(""),
 843
 844                         "[u8]" if is_ref => Some(""),
 845                         "[usize]" if is_ref => Some(""),
 846
 847                         "str" if is_ref => Some(""),
 848                         "String" if !is_ref => Some("String::from_utf8("),
 849                         // Note that we'll panic for String if is_ref, as we only have non-owned memory, we
 850                         // cannot create a &String.
 851
 852                         "std::time::Duration" => Some("std::time::Duration::from_secs("),
 853
 854                         "bitcoin::secp256k1::key::PublicKey"|"bitcoin::secp256k1::PublicKey"|"secp256k1::key::PublicKey"
 855                                 if is_ref => Some("&"),
 856                         "bitcoin::secp256k1::key::PublicKey"|"bitcoin::secp256k1::PublicKey"|"secp256k1::key::PublicKey"
 857                                 => Some(""),
 858                         "bitcoin::secp256k1::Signature" if is_ref => Some("&"),
 859                         "bitcoin::secp256k1::Signature" => Some(""),
 860                         "bitcoin::secp256k1::key::SecretKey"|"bitcoin::secp256k1::SecretKey"
 861                                 if is_ref => Some("&::bitcoin::secp256k1::key::SecretKey::from_slice(&unsafe { *"),
 862                         "bitcoin::secp256k1::key::SecretKey"|"bitcoin::secp256k1::SecretKey"
 863                                 if !is_ref => Some(""),
 864                         "bitcoin::blockdata::script::Script" if is_ref => Some("&::bitcoin::blockdata::script::Script::from(Vec::from("),
 865                         "bitcoin::blockdata::script::Script" if !is_ref => Some("::bitcoin::blockdata::script::Script::from("),
 866                         "bitcoin::blockdata::transaction::Transaction" if is_ref => Some("&"),
 867                         "bitcoin::blockdata::transaction::Transaction" => Some(""),
 868                         "bitcoin::blockdata::transaction::TxOut" if !is_ref => Some(""),
 869                         "bitcoin::network::constants::Network" => Some(""),
 870                         "bitcoin::blockdata::block::BlockHeader" => Some("&::bitcoin::consensus::encode::deserialize(unsafe { &*"),
 871                         "bitcoin::blockdata::block::Block" if is_ref => Some("&::bitcoin::consensus::encode::deserialize("),
 872
 873                         // Newtypes that we just expose in their original form.
 874                         "bitcoin::hash_types::Txid" if is_ref => Some("&::bitcoin::hash_types::Txid::from_slice(&unsafe { &*"),
 875                         "bitcoin::hash_types::Txid" if !is_ref => Some("::bitcoin::hash_types::Txid::from_slice(&"),
 876                         "bitcoin::hash_types::BlockHash" => Some("::bitcoin::hash_types::BlockHash::from_slice(&"),
 877                         "lightning::ln::channelmanager::PaymentHash" if !is_ref => Some("::lightning::ln::channelmanager::PaymentHash("),
 878                         "lightning::ln::channelmanager::PaymentHash" if is_ref => Some("&::lightning::ln::channelmanager::PaymentHash(unsafe { *"),
 879                         "lightning::ln::channelmanager::PaymentPreimage" if !is_ref => Some("::lightning::ln::channelmanager::PaymentPreimage("),
 880                         "lightning::ln::channelmanager::PaymentPreimage" if is_ref => Some("&::lightning::ln::channelmanager::PaymentPreimage(unsafe { *"),
 881                         "lightning::ln::channelmanager::PaymentSecret" => Some("::lightning::ln::channelmanager::PaymentSecret("),
 882
 883                         // List of traits we map (possibly during processing of other files):
 884                         "crate::util::logger::Logger" => Some(""),
 885
 886                         _ => None,
 887                 }.map(|s| s.to_owned())
 888         }
 889         fn from_c_conversion_suffix_from_path<'b>(&self, full_path: &str, is_ref: bool) -> Option<String> {
 890                 if self.is_primitive(full_path) {
 891                         return Some("".to_owned());
 892                 }
 893                 match full_path {
 894                         "Vec" if !is_ref => Some(""),
 895                         "Option" => Some(""),
 896                         "Result" if !is_ref => Some(""),
 897
 898                         "[u8; 32]" if is_ref => Some("}"),
 899                         "[u8; 32]" if !is_ref => Some(".data"),
 900                         "[u8; 16]" if !is_ref => Some(".data"),
 901                         "[u8; 10]" if !is_ref => Some(".data"),
 902                         "[u8; 4]" if !is_ref => Some(".data"),
 903                         "[u8; 3]" if !is_ref => Some(".data"),
 904
 905                         "[u8]" if is_ref => Some(".to_slice()"),
 906                         "[usize]" if is_ref => Some(".to_slice()"),
 907
 908                         "str" if is_ref => Some(".into()"),
 909                         "String" if !is_ref => Some(".into_rust()).unwrap()"),
 910
 911                         "std::time::Duration" => Some(")"),
 912
 913                         "bitcoin::secp256k1::key::PublicKey"|"bitcoin::secp256k1::PublicKey"|"secp256k1::key::PublicKey"
 914                                 => Some(".into_rust()"),
 915                         "bitcoin::secp256k1::Signature" => Some(".into_rust()"),
 916                         "bitcoin::secp256k1::key::SecretKey"|"bitcoin::secp256k1::SecretKey"
 917                                 if !is_ref => Some(".into_rust()"),
 918                         "bitcoin::secp256k1::key::SecretKey"|"bitcoin::secp256k1::SecretKey"
 919                                 if is_ref => Some("}[..]).unwrap()"),
 920                         "bitcoin::blockdata::script::Script" if is_ref => Some(".to_slice()))"),
 921                         "bitcoin::blockdata::script::Script" if !is_ref => Some(".into_rust())"),
 922                         "bitcoin::blockdata::transaction::Transaction" => Some(".into_bitcoin()"),
 923                         "bitcoin::blockdata::transaction::TxOut" if !is_ref => Some(".into_rust()"),
 924                         "bitcoin::network::constants::Network" => Some(".into_bitcoin()"),
 925                         "bitcoin::blockdata::block::BlockHeader" => Some(" }).unwrap()"),
 926                         "bitcoin::blockdata::block::Block" => Some(".to_slice()).unwrap()"),
 927
 928                         // Newtypes that we just expose in their original form.
 929                         "bitcoin::hash_types::Txid" if is_ref => Some(" }[..]).unwrap()"),
 930                         "bitcoin::hash_types::Txid" => Some(".data[..]).unwrap()"),
 931                         "bitcoin::hash_types::BlockHash" if !is_ref => Some(".data[..]).unwrap()"),
 932                         "lightning::ln::channelmanager::PaymentHash" if !is_ref => Some(".data)"),
 933                         "lightning::ln::channelmanager::PaymentHash" if is_ref => Some(" })"),
 934                         "lightning::ln::channelmanager::PaymentPreimage" if !is_ref => Some(".data)"),
 935                         "lightning::ln::channelmanager::PaymentPreimage" if is_ref => Some(" })"),
 936                         "lightning::ln::channelmanager::PaymentSecret" => Some(".data)"),
 937
 938                         // List of traits we map (possibly during processing of other files):
 939                         "crate::util::logger::Logger" => Some(""),
 940
 941                         _ => None,
 942                 }.map(|s| s.to_owned())
 943         }
 944
 945         fn to_c_conversion_new_var_from_path<'b>(&self, full_path: &str, is_ref: bool) -> Option<(&'b str, &'b str)> {
 946                 if self.is_primitive(full_path) {
 947                         return None;
 948                 }
 949                 match full_path {
 950                         "[u8]" if is_ref => Some(("crate::c_types::u8slice::from_slice(", ")")),
 951                         "[usize]" if is_ref => Some(("crate::c_types::usizeslice::from_slice(", ")")),
 952
 953                         "bitcoin::blockdata::block::BlockHeader" if is_ref => Some(("{ let mut s = [0u8; 80]; s[..].copy_from_slice(&::bitcoin::consensus::encode::serialize(", ")); s }")),
 954                         "bitcoin::blockdata::block::Block" if is_ref => Some(("::bitcoin::consensus::encode::serialize(", ")")),
 955                         "bitcoin::hash_types::Txid" => None,
 956
 957                         // Override the default since Records contain an fmt with a lifetime:
 958                         // TODO: We should include the other record fields
 959                         "lightning::util::logger::Record" => Some(("std::ffi::CString::new(format!(\"{}\", ", ".args)).unwrap()")),
 960                         _ => None,
 961                 }.map(|s| s.to_owned())
 962         }
 963         fn to_c_conversion_inline_prefix_from_path(&self, full_path: &str, is_ref: bool, _ptr_for_ref: bool) -> Option<String> {
 964                 if self.is_primitive(full_path) {
 965                         return Some("".to_owned());
 966                 }
 967                 match full_path {
 968                         "Result" if !is_ref => Some("local_"),
 969                         "Vec" if !is_ref => Some("local_"),
 970                         "Option" => Some("local_"),
 971
 972                         "[u8; 32]" if !is_ref => Some("crate::c_types::ThirtyTwoBytes { data: "),
 973                         "[u8; 32]" if is_ref => Some(""),
 974                         "[u8; 16]" if !is_ref => Some("crate::c_types::SixteenBytes { data: "),
 975                         "[u8; 10]" if !is_ref => Some("crate::c_types::TenBytes { data: "),
 976                         "[u8; 4]" if !is_ref => Some("crate::c_types::FourBytes { data: "),
 977                         "[u8; 3]" if is_ref => Some(""),
 978
 979                         "[u8]" if is_ref => Some("local_"),
 980                         "[usize]" if is_ref => Some("local_"),
 981
 982                         "str" if is_ref => Some(""),
 983                         "String" => Some(""),
 984
 985                         "std::time::Duration" => Some(""),
 986                         "std::io::Error" if !is_ref => Some("crate::c_types::IOError::from_rust("),
 987
 988                         "bitcoin::secp256k1::key::PublicKey"|"bitcoin::secp256k1::PublicKey"|"secp256k1::key::PublicKey"
 989                                 => Some("crate::c_types::PublicKey::from_rust(&"),
 990                         "bitcoin::secp256k1::Signature" => Some("crate::c_types::Signature::from_rust(&"),
 991                         "bitcoin::secp256k1::key::SecretKey"|"bitcoin::secp256k1::SecretKey"
 992                                 if is_ref => Some(""),
 993                         "bitcoin::secp256k1::key::SecretKey"|"bitcoin::secp256k1::SecretKey"
 994                                 if !is_ref => Some("crate::c_types::SecretKey::from_rust("),
 995                         "bitcoin::secp256k1::Error"|"secp256k1::Error"
 996                                 if !is_ref => Some("crate::c_types::Secp256k1Error::from_rust("),
 997                         "bitcoin::blockdata::script::Script" if is_ref => Some("crate::c_types::u8slice::from_slice(&"),
 998                         "bitcoin::blockdata::script::Script" if !is_ref => Some(""),
 999                         "bitcoin::blockdata::transaction::Transaction" if is_ref => Some("crate::c_types::Transaction::from_bitcoin("),
1000                         "bitcoin::blockdata::transaction::Transaction" => Some("crate::c_types::Transaction::from_bitcoin(&"),
1001                         "bitcoin::blockdata::transaction::OutPoint" => Some("crate::c_types::bitcoin_to_C_outpoint("),
1002                         "bitcoin::blockdata::transaction::TxOut" if !is_ref => Some("crate::c_types::TxOut::from_rust("),
1003                         "bitcoin::network::constants::Network" => Some("crate::bitcoin::network::Network::from_bitcoin("),
1004                         "bitcoin::blockdata::block::BlockHeader" if is_ref => Some("&local_"),
1005                         "bitcoin::blockdata::block::Block" if is_ref => Some("crate::c_types::u8slice::from_slice(&local_"),
1006
1007                         "bitcoin::hash_types::Txid" if !is_ref => Some("crate::c_types::ThirtyTwoBytes { data: "),
1008
1009                         // Newtypes that we just expose in their original form.
1010                         "bitcoin::hash_types::Txid"|"bitcoin::hash_types::BlockHash"|"bitcoin_hashes::sha256::Hash"
1011                                 if is_ref => Some(""),
1012                         "bitcoin::hash_types::Txid"|"bitcoin::hash_types::BlockHash"|"bitcoin_hashes::sha256::Hash"
1013                                 if !is_ref => Some("crate::c_types::ThirtyTwoBytes { data: "),
1014                         "bitcoin::secp256k1::Message" if !is_ref => Some("crate::c_types::ThirtyTwoBytes { data: "),
1015                         "lightning::ln::channelmanager::PaymentHash" if is_ref => Some("&"),
1016                         "lightning::ln::channelmanager::PaymentHash" if !is_ref => Some("crate::c_types::ThirtyTwoBytes { data: "),
1017                         "lightning::ln::channelmanager::PaymentPreimage" if is_ref => Some("&"),
1018                         "lightning::ln::channelmanager::PaymentPreimage" => Some("crate::c_types::ThirtyTwoBytes { data: "),
1019                         "lightning::ln::channelmanager::PaymentSecret" if !is_ref => Some("crate::c_types::ThirtyTwoBytes { data: "),
1020
1021                         // Override the default since Records contain an fmt with a lifetime:
1022                         "lightning::util::logger::Record" => Some("local_"),
1023
1024                         _ => None,
1025                 }.map(|s| s.to_owned())
1026         }
1027         fn to_c_conversion_inline_suffix_from_path(&self, full_path: &str, is_ref: bool, _ptr_for_ref: bool) -> Option<String> {
1028                 if self.is_primitive(full_path) {
1029                         return Some("".to_owned());
1030                 }
1031                 match full_path {
1032                         "Result" if !is_ref => Some(""),
1033                         "Vec" if !is_ref => Some(".into()"),
1034                         "Option" => Some(""),
1035
1036                         "[u8; 32]" if !is_ref => Some(" }"),
1037                         "[u8; 32]" if is_ref => Some(""),
1038                         "[u8; 16]" if !is_ref => Some(" }"),
1039                         "[u8; 10]" if !is_ref => Some(" }"),
1040                         "[u8; 4]" if !is_ref => Some(" }"),
1041                         "[u8; 3]" if is_ref => Some(""),
1042
1043                         "[u8]" if is_ref => Some(""),
1044                         "[usize]" if is_ref => Some(""),
1045
1046                         "str" if is_ref => Some(".into()"),
1047                         "String" if !is_ref => Some(".into_bytes().into()"),
1048                         "String" if is_ref => Some(".as_str().into()"),
1049
1050                         "std::time::Duration" => Some(".as_secs()"),
1051                         "std::io::Error" if !is_ref => Some(")"),
1052
1053                         "bitcoin::secp256k1::key::PublicKey"|"bitcoin::secp256k1::PublicKey"|"secp256k1::key::PublicKey"
1054                                 => Some(")"),
1055                         "bitcoin::secp256k1::Signature" => Some(")"),
1056                         "bitcoin::secp256k1::key::SecretKey"|"bitcoin::secp256k1::SecretKey"
1057                                 if !is_ref => Some(")"),
1058                         "bitcoin::secp256k1::key::SecretKey"|"bitcoin::secp256k1::SecretKey"
1059                                 if is_ref => Some(".as_ref()"),
1060                         "bitcoin::secp256k1::Error"|"secp256k1::Error"
1061                                 if !is_ref => Some(")"),
1062                         "bitcoin::blockdata::script::Script" if is_ref => Some("[..])"),
1063                         "bitcoin::blockdata::script::Script" if !is_ref => Some(".into_bytes().into()"),
1064                         "bitcoin::blockdata::transaction::Transaction" => Some(")"),
1065                         "bitcoin::blockdata::transaction::OutPoint" => Some(")"),
1066                         "bitcoin::blockdata::transaction::TxOut" if !is_ref => Some(")"),
1067                         "bitcoin::network::constants::Network" => Some(")"),
1068                         "bitcoin::blockdata::block::BlockHeader" if is_ref => Some(""),
1069                         "bitcoin::blockdata::block::Block" if is_ref => Some(")"),
1070
1071                         "bitcoin::hash_types::Txid" if !is_ref => Some(".into_inner() }"),
1072
1073                         // Newtypes that we just expose in their original form.
1074                         "bitcoin::hash_types::Txid"|"bitcoin::hash_types::BlockHash"|"bitcoin_hashes::sha256::Hash"
1075                                 if is_ref => Some(".as_inner()"),
1076                         "bitcoin::hash_types::Txid"|"bitcoin::hash_types::BlockHash"|"bitcoin_hashes::sha256::Hash"
1077                                 if !is_ref => Some(".into_inner() }"),
1078                         "bitcoin::secp256k1::Message" if !is_ref => Some(".as_ref().clone() }"),
1079                         "lightning::ln::channelmanager::PaymentHash" if is_ref => Some(".0"),
1080                         "lightning::ln::channelmanager::PaymentHash" => Some(".0 }"),
1081                         "lightning::ln::channelmanager::PaymentPreimage" if is_ref => Some(".0"),
1082                         "lightning::ln::channelmanager::PaymentPreimage" => Some(".0 }"),
1083                         "lightning::ln::channelmanager::PaymentSecret" if !is_ref => Some(".0 }"),
1084
1085                         // Override the default since Records contain an fmt with a lifetime:
1086                         "lightning::util::logger::Record" => Some(".as_ptr()"),
1087
1088                         _ => None,
1089                 }.map(|s| s.to_owned())
1090         }
1091
1092         fn empty_val_check_suffix_from_path(&self, full_path: &str) -> Option<&str> {
1093                 match full_path {
1094                         "lightning::ln::channelmanager::PaymentSecret" => Some(".data == [0; 32]"),
1095                         "secp256k1::key::PublicKey"|"bitcoin::secp256k1::key::PublicKey" => Some(".is_null()"),
1096                         "bitcoin::secp256k1::Signature" => Some(".is_null()"),
1097                         _ => None
1098                 }
1099         }
1100
1101         // ****************************
1102         // *** Container Processing ***
1103         // ****************************
1104
1105         /// Returns the module path in the generated mapping crate to the containers which we generate
1106         /// when writing to CrateTypes::template_file.
1107         pub fn generated_container_path() -> &'static str {
1108                 "crate::c_types::derived"
1109         }
1110         /// Returns the module path in the generated mapping crate to the container templates, which
1111         /// are then concretized and put in the generated container path/template_file.
1112         fn container_templ_path() -> &'static str {
1113                 "crate::c_types"
1114         }
1115
1116         /// Returns true if the path containing the given args is a "transparent" container, ie an
1117         /// Option or a container which does not require a generated continer class.
1118         fn is_transparent_container<'i, I: Iterator<Item=&'i syn::Type>>(&self, full_path: &str, _is_ref: bool, mut args: I) -> bool {
1119                 if full_path == "Option" {
1120                         let inner = args.next().unwrap();
1121                         assert!(args.next().is_none());
1122                         match inner {
1123                                 syn::Type::Reference(_) => true,
1124                                 syn::Type::Path(p) => {
1125                                         if let Some(resolved) = self.maybe_resolve_path(&p.path, None) {
1126                                                 if self.is_primitive(&resolved) { false } else { true }
1127                                         } else { true }
1128                                 },
1129                                 syn::Type::Tuple(_) => false,
1130                                 _ => unimplemented!(),
1131                         }
1132                 } else { false }
1133         }
1134         /// Returns true if the path is a "transparent" container, ie an Option or a container which does
1135         /// not require a generated continer class.
1136         fn is_path_transparent_container(&self, full_path: &syn::Path, generics: Option<&GenericTypes>, is_ref: bool) -> bool {
1137                 let inner_iter = match &full_path.segments.last().unwrap().arguments {
1138                         syn::PathArguments::None => return false,
1139                         syn::PathArguments::AngleBracketed(args) => args.args.iter().map(|arg| {
1140                                 if let syn::GenericArgument::Type(ref ty) = arg {
1141                                         ty
1142                                 } else { unimplemented!() }
1143                         }),
1144                         syn::PathArguments::Parenthesized(_) => unimplemented!(),
1145                 };
1146                 self.is_transparent_container(&self.resolve_path(full_path, generics), is_ref, inner_iter)
1147         }
1148         /// Returns true if this is a known, supported, non-transparent container.
1149         fn is_known_container(&self, full_path: &str, is_ref: bool) -> bool {
1150                 (full_path == "Result" && !is_ref) || (full_path == "Vec" && !is_ref) || full_path.ends_with("Tuple") || full_path == "Option"
1151         }
1152         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)
1153                         // Returns prefix + Vec<(prefix, var-name-to-inline-convert)> + suffix
1154                         // expecting one element in the vec per generic type, each of which is inline-converted
1155                         -> Option<(&'b str, Vec<(String, String)>, &'b str, ContainerPrefixLocation)> {
1156                 match full_path {
1157                         "Result" if !is_ref => {
1158                                 Some(("match ",
1159                                                 vec![(" { Ok(mut o) => crate::c_types::CResultTempl::ok(".to_string(), "o".to_string()),
1160                                                         (").into(), Err(mut e) => crate::c_types::CResultTempl::err(".to_string(), "e".to_string())],
1161                                                 ").into() }", ContainerPrefixLocation::PerConv))
1162                         },
1163                         "Vec" if !is_ref => {
1164                                 Some(("Vec::new(); for mut item in ", vec![(format!(".drain(..) {{ local_{}.push(", var_name), "item".to_string())], "); }", ContainerPrefixLocation::PerConv))
1165                         },
1166                         "Vec" => {
1167                                 // We should only get here if the single contained has an inner
1168                                 assert!(self.c_type_has_inner(single_contained.unwrap()));
1169                                 Some(("Vec::new(); for mut item in ", vec![(format!(".drain(..) {{ local_{}.push(", var_name), "*item".to_string())], "); }", ContainerPrefixLocation::PerConv))
1170                         },
1171                         "Slice" => {
1172                                 Some(("Vec::new(); for item in ", vec![(format!(".iter() {{ local_{}.push(", var_name), "*item".to_string())], "); }", ContainerPrefixLocation::PerConv))
1173                         },
1174                         "Option" => {
1175                                 if let Some(syn::Type::Path(p)) = single_contained {
1176                                         let inner_path = self.resolve_path(&p.path, generics);
1177                                         if self.is_primitive(&inner_path) {
1178                                                 return Some(("if ", vec![
1179                                                         (format!(".is_none() {{ {}::COption_{}Z::None }} else {{ ", Self::generated_container_path(), inner_path),
1180                                                          format!("{}::COption_{}Z::Some({}.unwrap())", Self::generated_container_path(), inner_path, var_access))
1181                                                         ], " }", ContainerPrefixLocation::NoPrefix));
1182                                         } else if self.c_type_has_inner_from_path(&inner_path) {
1183                                                 if is_ref {
1184                                                         return Some(("if ", vec![
1185                                                                 (".is_none() { std::ptr::null() } else { ".to_owned(), format!("({}.as_ref().unwrap())", var_access))
1186                                                                 ], " }", ContainerPrefixLocation::OutsideConv));
1187                                                 } else {
1188                                                         return Some(("if ", vec![
1189                                                                 (".is_none() { std::ptr::null_mut() } else { ".to_owned(), format!("({}.unwrap())", var_access))
1190                                                                 ], " }", ContainerPrefixLocation::OutsideConv));
1191                                                 }
1192                                         }
1193                                 }
1194                                 if let Some(t) = single_contained {
1195                                         let mut v = Vec::new();
1196                                         self.write_empty_rust_val(generics, &mut v, t);
1197                                         let s = String::from_utf8(v).unwrap();
1198                                         return Some(("if ", vec![
1199                                                 (format!(".is_none() {{ {} }} else {{ ", s), format!("({}.unwrap())", var_access))
1200                                                 ], " }", ContainerPrefixLocation::PerConv));
1201                                 } else { unreachable!(); }
1202                         },
1203                         _ => None,
1204                 }
1205         }
1206
1207         /// only_contained_has_inner implies that there is only one contained element in the container
1208         /// and it has an inner field (ie is an "opaque" type we've defined).
1209         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)
1210                         // Returns prefix + Vec<(prefix, var-name-to-inline-convert)> + suffix
1211                         // expecting one element in the vec per generic type, each of which is inline-converted
1212                         -> Option<(&'b str, Vec<(String, String)>, &'b str, ContainerPrefixLocation)> {
1213                 match full_path {
1214                         "Result" if !is_ref => {
1215                                 Some(("match ",
1216                                                 vec![(".result_ok { true => Ok(".to_string(), format!("(*unsafe {{ Box::from_raw(<*mut _>::take_ptr(&mut {}.contents.result)) }})", var_access)),
1217                                                      ("), false => Err(".to_string(), format!("(*unsafe {{ Box::from_raw(<*mut _>::take_ptr(&mut {}.contents.err)) }})", var_access))],
1218                                                 ")}", ContainerPrefixLocation::PerConv))
1219                         },
1220                         "Slice" if is_ref => {
1221                                 Some(("Vec::new(); for mut item in ", vec![(format!(".as_slice().iter() {{ local_{}.push(", var_name), "item".to_string())], "); }", ContainerPrefixLocation::PerConv))
1222                         },
1223                         "Vec"|"Slice" => {
1224                                 Some(("Vec::new(); for mut item in ", vec![(format!(".into_rust().drain(..) {{ local_{}.push(", var_name), "item".to_string())], "); }", ContainerPrefixLocation::PerConv))
1225                         },
1226                         "Option" => {
1227                                 if let Some(syn::Type::Path(p)) = single_contained {
1228                                         let inner_path = self.resolve_path(&p.path, generics);
1229                                         if self.is_primitive(&inner_path) {
1230                                                 return Some(("if ", vec![(".is_some() { Some(".to_string(), format!("{}.take()", var_access))], ") } else { None }", ContainerPrefixLocation::NoPrefix))
1231                                         } else if self.c_type_has_inner_from_path(&inner_path) {
1232                                                 if is_ref {
1233                                                         return Some(("if ", vec![(".inner.is_null() { None } else { Some((*".to_string(), format!("{}", var_access))], ").clone()) }", ContainerPrefixLocation::PerConv))
1234                                                 } else {
1235                                                         return Some(("if ", vec![(".inner.is_null() { None } else { Some(".to_string(), format!("{}", var_access))], ") }", ContainerPrefixLocation::PerConv));
1236                                                 }
1237                                         }
1238                                 }
1239
1240                                 if let Some(t) = single_contained {
1241                                         match t {
1242                                                 syn::Type::Reference(_)|syn::Type::Path(_)|syn::Type::Slice(_) => {
1243                                                         let mut v = Vec::new();
1244                                                         let ret_ref = self.write_empty_rust_val_check_suffix(generics, &mut v, t);
1245                                                         let s = String::from_utf8(v).unwrap();
1246                                                         match ret_ref {
1247                                                                 EmptyValExpectedTy::ReferenceAsPointer =>
1248                                                                         return Some(("if ", vec![
1249                                                                                 (format!("{} {{ None }} else {{ Some(", s), format!("unsafe {{ &mut *{} }}", var_access))
1250                                                                         ], ") }", ContainerPrefixLocation::NoPrefix)),
1251                                                                 EmptyValExpectedTy::OwnedPointer => {
1252                                                                         if let syn::Type::Slice(_) = t {
1253                                                                                         panic!();
1254                                                                         }
1255                                                                         return Some(("if ", vec![
1256                                                                                 (format!("{} {{ None }} else {{ Some(", s), format!("unsafe {{ *Box::from_raw({}) }}", var_access))
1257                                                                         ], ") }", ContainerPrefixLocation::NoPrefix));
1258                                                                 }
1259                                                                 EmptyValExpectedTy::NonPointer =>
1260                                                                         return Some(("if ", vec![
1261                                                                                 (format!("{} {{ None }} else {{ Some(", s), format!("{}", var_access))
1262                                                                         ], ") }", ContainerPrefixLocation::PerConv)),
1263                                                         }
1264                                                 },
1265                                                 syn::Type::Tuple(_) => {
1266                                                         return Some(("if ", vec![(".is_some() { Some(".to_string(), format!("{}.take()", var_access))], ") } else { None }", ContainerPrefixLocation::PerConv))
1267                                                 },
1268                                                 _ => unimplemented!(),
1269                                         }
1270                                 } else { unreachable!(); }
1271                         },
1272                         _ => None,
1273                 }
1274         }
1275
1276         // *************************************************
1277         // *** Type definition during main.rs processing ***
1278         // *************************************************
1279
1280         pub fn get_declared_type(&'a self, ident: &syn::Ident) -> Option<&'a DeclType<'c>> {
1281                 self.types.get_declared_type(ident)
1282         }
1283         /// Returns true if the object at the given path is mapped as X { inner: *mut origX, .. }.
1284         pub fn c_type_has_inner_from_path(&self, full_path: &str) -> bool {
1285                 self.crate_types.opaques.get(full_path).is_some()
1286         }
1287         /// Returns true if the object at the given path is mapped as X { inner: *mut origX, .. }.
1288         pub fn c_type_has_inner(&self, ty: &syn::Type) -> bool {
1289                 match ty {
1290                         syn::Type::Path(p) => {
1291                                 let full_path = self.resolve_path(&p.path, None);
1292                                 self.c_type_has_inner_from_path(&full_path)
1293                         },
1294                         _ => false,
1295                 }
1296         }
1297
1298         pub fn maybe_resolve_ident(&self, id: &syn::Ident) -> Option<String> {
1299                 self.types.maybe_resolve_ident(id)
1300         }
1301
1302         pub fn maybe_resolve_non_ignored_ident(&self, id: &syn::Ident) -> Option<String> {
1303                 self.types.maybe_resolve_non_ignored_ident(id)
1304         }
1305
1306         pub fn maybe_resolve_path(&self, p_arg: &syn::Path, generics: Option<&GenericTypes>) -> Option<String> {
1307                 self.types.maybe_resolve_path(p_arg, generics)
1308         }
1309         pub fn resolve_path(&self, p: &syn::Path, generics: Option<&GenericTypes>) -> String {
1310                 self.maybe_resolve_path(p, generics).unwrap()
1311         }
1312
1313         // ***********************************
1314         // *** Original Rust Type Printing ***
1315         // ***********************************
1316
1317         fn in_rust_prelude(resolved_path: &str) -> bool {
1318                 match resolved_path {
1319                         "Vec" => true,
1320                         "Result" => true,
1321                         "Option" => true,
1322                         _ => false,
1323                 }
1324         }
1325
1326         fn write_rust_path<W: std::io::Write>(&self, w: &mut W, generics_resolver: Option<&GenericTypes>, path: &syn::Path) {
1327                 if let Some(resolved) = self.maybe_resolve_path(&path, generics_resolver) {
1328                         if self.is_primitive(&resolved) {
1329                                 write!(w, "{}", path.get_ident().unwrap()).unwrap();
1330                         } else {
1331                                 // TODO: We should have a generic "is from a dependency" check here instead of
1332                                 // checking for "bitcoin" explicitly.
1333                                 if resolved.starts_with("bitcoin::") || Self::in_rust_prelude(&resolved) {
1334                                         write!(w, "{}", resolved).unwrap();
1335                                 // If we're printing a generic argument, it needs to reference the crate, otherwise
1336                                 // the original crate:
1337                                 } else if self.maybe_resolve_path(&path, None).as_ref() == Some(&resolved) {
1338                                         write!(w, "{}", resolved).unwrap();
1339                                 } else {
1340                                         write!(w, "crate::{}", resolved).unwrap();
1341                                 }
1342                         }
1343                         if let syn::PathArguments::AngleBracketed(args) = &path.segments.iter().last().unwrap().arguments {
1344                                 self.write_rust_generic_arg(w, generics_resolver, args.args.iter());
1345                         }
1346                 } else {
1347                         if path.leading_colon.is_some() {
1348                                 write!(w, "::").unwrap();
1349                         }
1350                         for (idx, seg) in path.segments.iter().enumerate() {
1351                                 if idx != 0 { write!(w, "::").unwrap(); }
1352                                 write!(w, "{}", seg.ident).unwrap();
1353                                 if let syn::PathArguments::AngleBracketed(args) = &seg.arguments {
1354                                         self.write_rust_generic_arg(w, generics_resolver, args.args.iter());
1355                                 }
1356                         }
1357                 }
1358         }
1359         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>) {
1360                 let mut had_params = false;
1361                 for (idx, arg) in generics.enumerate() {
1362                         if idx != 0 { write!(w, ", ").unwrap(); } else { write!(w, "<").unwrap(); }
1363                         had_params = true;
1364                         match arg {
1365                                 syn::GenericParam::Lifetime(lt) => write!(w, "'{}", lt.lifetime.ident).unwrap(),
1366                                 syn::GenericParam::Type(t) => {
1367                                         write!(w, "{}", t.ident).unwrap();
1368                                         if t.colon_token.is_some() { write!(w, ":").unwrap(); }
1369                                         for (idx, bound) in t.bounds.iter().enumerate() {
1370                                                 if idx != 0 { write!(w, " + ").unwrap(); }
1371                                                 match bound {
1372                                                         syn::TypeParamBound::Trait(tb) => {
1373                                                                 if tb.paren_token.is_some() || tb.lifetimes.is_some() { unimplemented!(); }
1374                                                                 self.write_rust_path(w, generics_resolver, &tb.path);
1375                                                         },
1376                                                         _ => unimplemented!(),
1377                                                 }
1378                                         }
1379                                         if t.eq_token.is_some() || t.default.is_some() { unimplemented!(); }
1380                                 },
1381                                 _ => unimplemented!(),
1382                         }
1383                 }
1384                 if had_params { write!(w, ">").unwrap(); }
1385         }
1386
1387         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>) {
1388                 write!(w, "<").unwrap();
1389                 for (idx, arg) in generics.enumerate() {
1390                         if idx != 0 { write!(w, ", ").unwrap(); }
1391                         match arg {
1392                                 syn::GenericArgument::Type(t) => self.write_rust_type(w, generics_resolver, t),
1393                                 _ => unimplemented!(),
1394                         }
1395                 }
1396                 write!(w, ">").unwrap();
1397         }
1398         pub fn write_rust_type<W: std::io::Write>(&self, w: &mut W, generics: Option<&GenericTypes>, t: &syn::Type) {
1399                 match t {
1400                         syn::Type::Path(p) => {
1401                                 if p.qself.is_some() {
1402                                         unimplemented!();
1403                                 }
1404                                 self.write_rust_path(w, generics, &p.path);
1405                         },
1406                         syn::Type::Reference(r) => {
1407                                 write!(w, "&").unwrap();
1408                                 if let Some(lft) = &r.lifetime {
1409                                         write!(w, "'{} ", lft.ident).unwrap();
1410                                 }
1411                                 if r.mutability.is_some() {
1412                                         write!(w, "mut ").unwrap();
1413                                 }
1414                                 self.write_rust_type(w, generics, &*r.elem);
1415                         },
1416                         syn::Type::Array(a) => {
1417                                 write!(w, "[").unwrap();
1418                                 self.write_rust_type(w, generics, &a.elem);
1419                                 if let syn::Expr::Lit(l) = &a.len {
1420                                         if let syn::Lit::Int(i) = &l.lit {
1421                                                 write!(w, "; {}]", i).unwrap();
1422                                         } else { unimplemented!(); }
1423                                 } else { unimplemented!(); }
1424                         }
1425                         syn::Type::Slice(s) => {
1426                                 write!(w, "[").unwrap();
1427                                 self.write_rust_type(w, generics, &s.elem);
1428                                 write!(w, "]").unwrap();
1429                         },
1430                         syn::Type::Tuple(s) => {
1431                                 write!(w, "(").unwrap();
1432                                 for (idx, t) in s.elems.iter().enumerate() {
1433                                         if idx != 0 { write!(w, ", ").unwrap(); }
1434                                         self.write_rust_type(w, generics, &t);
1435                                 }
1436                                 write!(w, ")").unwrap();
1437                         },
1438                         _ => unimplemented!(),
1439                 }
1440         }
1441
1442         /// Prints a constructor for something which is "uninitialized" (but obviously not actually
1443         /// unint'd memory).
1444         pub fn write_empty_rust_val<W: std::io::Write>(&self, generics: Option<&GenericTypes>, w: &mut W, t: &syn::Type) {
1445                 match t {
1446                         syn::Type::Path(p) => {
1447                                 let resolved = self.resolve_path(&p.path, generics);
1448                                 if self.crate_types.opaques.get(&resolved).is_some() {
1449                                         write!(w, "crate::{} {{ inner: std::ptr::null_mut(), is_owned: true }}", resolved).unwrap();
1450                                 } else {
1451                                         // Assume its a manually-mapped C type, where we can just define an null() fn
1452                                         write!(w, "{}::null()", self.c_type_from_path(&resolved, false, false).unwrap()).unwrap();
1453                                 }
1454                         },
1455                         syn::Type::Array(a) => {
1456                                 if let syn::Expr::Lit(l) = &a.len {
1457                                         if let syn::Lit::Int(i) = &l.lit {
1458                                                 if i.base10_digits().parse::<usize>().unwrap() < 32 {
1459                                                         // Blindly assume that if we're trying to create an empty value for an
1460                                                         // array < 32 entries that all-0s may be a valid state.
1461                                                         unimplemented!();
1462                                                 }
1463                                                 let arrty = format!("[u8; {}]", i.base10_digits());
1464                                                 write!(w, "{}", self.to_c_conversion_inline_prefix_from_path(&arrty, false, false).unwrap()).unwrap();
1465                                                 write!(w, "[0; {}]", i.base10_digits()).unwrap();
1466                                                 write!(w, "{}", self.to_c_conversion_inline_suffix_from_path(&arrty, false, false).unwrap()).unwrap();
1467                                         } else { unimplemented!(); }
1468                                 } else { unimplemented!(); }
1469                         }
1470                         _ => unimplemented!(),
1471                 }
1472         }
1473
1474         fn is_real_type_array(&self, resolved_type: &str) -> Option<syn::Type> {
1475                 if let Some(real_ty) = self.c_type_from_path(&resolved_type, true, false) {
1476                         if real_ty.ends_with("]") && real_ty.starts_with("*const [u8; ") {
1477                                 let mut split = real_ty.split("; ");
1478                                 split.next().unwrap();
1479                                 let tail_str = split.next().unwrap();
1480                                 assert!(split.next().is_none());
1481                                 let len = usize::from_str_radix(&tail_str[..tail_str.len() - 1], 10).unwrap();
1482                                 Some(parse_quote!([u8; #len]))
1483                         } else { None }
1484                 } else { None }
1485         }
1486
1487         /// Prints a suffix to determine if a variable is empty (ie was set by write_empty_rust_val).
1488         /// See EmptyValExpectedTy for information on return types.
1489         fn write_empty_rust_val_check_suffix<W: std::io::Write>(&self, generics: Option<&GenericTypes>, w: &mut W, t: &syn::Type) -> EmptyValExpectedTy {
1490                 match t {
1491                         syn::Type::Path(p) => {
1492                                 let resolved = self.resolve_path(&p.path, generics);
1493                                 if let Some(arr_ty) = self.is_real_type_array(&resolved) {
1494                                         write!(w, ".data").unwrap();
1495                                         return self.write_empty_rust_val_check_suffix(generics, w, &arr_ty);
1496                                 }
1497                                 if self.crate_types.opaques.get(&resolved).is_some() {
1498                                         write!(w, ".inner.is_null()").unwrap();
1499                                         EmptyValExpectedTy::NonPointer
1500                                 } else {
1501                                         if let Some(suffix) = self.empty_val_check_suffix_from_path(&resolved) {
1502                                                 write!(w, "{}", suffix).unwrap();
1503                                                 // We may eventually need to allow empty_val_check_suffix_from_path to specify if we need a deref or not
1504                                                 EmptyValExpectedTy::NonPointer
1505                                         } else {
1506                                                 write!(w, " == std::ptr::null_mut()").unwrap();
1507                                                 EmptyValExpectedTy::OwnedPointer
1508                                         }
1509                                 }
1510                         },
1511                         syn::Type::Array(a) => {
1512                                 if let syn::Expr::Lit(l) = &a.len {
1513                                         if let syn::Lit::Int(i) = &l.lit {
1514                                                 write!(w, " == [0; {}]", i.base10_digits()).unwrap();
1515                                                 EmptyValExpectedTy::NonPointer
1516                                         } else { unimplemented!(); }
1517                                 } else { unimplemented!(); }
1518                         },
1519                         syn::Type::Slice(_) => {
1520                                 // Option<[]> always implies that we want to treat len() == 0 differently from
1521                                 // None, so we always map an Option<[]> into a pointer.
1522                                 write!(w, " == std::ptr::null_mut()").unwrap();
1523                                 EmptyValExpectedTy::ReferenceAsPointer
1524                         },
1525                         _ => unimplemented!(),
1526                 }
1527         }
1528
1529         /// Prints a suffix to determine if a variable is empty (ie was set by write_empty_rust_val).
1530         pub fn write_empty_rust_val_check<W: std::io::Write>(&self, generics: Option<&GenericTypes>, w: &mut W, t: &syn::Type, var_access: &str) {
1531                 match t {
1532                         syn::Type::Path(_) => {
1533                                 write!(w, "{}", var_access).unwrap();
1534                                 self.write_empty_rust_val_check_suffix(generics, w, t);
1535                         },
1536                         syn::Type::Array(a) => {
1537                                 if let syn::Expr::Lit(l) = &a.len {
1538                                         if let syn::Lit::Int(i) = &l.lit {
1539                                                 let arrty = format!("[u8; {}]", i.base10_digits());
1540                                                 // We don't (yet) support a new-var conversion here.
1541                                                 assert!(self.from_c_conversion_new_var_from_path(&arrty, false).is_none());
1542                                                 write!(w, "{}{}{}",
1543                                                         self.from_c_conversion_prefix_from_path(&arrty, false).unwrap(),
1544                                                         var_access,
1545                                                         self.from_c_conversion_suffix_from_path(&arrty, false).unwrap()).unwrap();
1546                                                 self.write_empty_rust_val_check_suffix(generics, w, t);
1547                                         } else { unimplemented!(); }
1548                                 } else { unimplemented!(); }
1549                         }
1550                         _ => unimplemented!(),
1551                 }
1552         }
1553
1554         // ********************************
1555         // *** Type conversion printing ***
1556         // ********************************
1557
1558         /// Returns true we if can just skip passing this to C entirely
1559         pub fn skip_arg(&self, t: &syn::Type, generics: Option<&GenericTypes>) -> bool {
1560                 match t {
1561                         syn::Type::Path(p) => {
1562                                 if p.qself.is_some() { unimplemented!(); }
1563                                 if let Some(full_path) = self.maybe_resolve_path(&p.path, generics) {
1564                                         self.skip_path(&full_path)
1565                                 } else { false }
1566                         },
1567                         syn::Type::Reference(r) => {
1568                                 self.skip_arg(&*r.elem, generics)
1569                         },
1570                         _ => false,
1571                 }
1572         }
1573         pub fn no_arg_to_rust<W: std::io::Write>(&self, w: &mut W, t: &syn::Type, generics: Option<&GenericTypes>) {
1574                 match t {
1575                         syn::Type::Path(p) => {
1576                                 if p.qself.is_some() { unimplemented!(); }
1577                                 if let Some(full_path) = self.maybe_resolve_path(&p.path, generics) {
1578                                         write!(w, "{}", self.no_arg_path_to_rust(&full_path)).unwrap();
1579                                 }
1580                         },
1581                         syn::Type::Reference(r) => {
1582                                 self.no_arg_to_rust(w, &*r.elem, generics);
1583                         },
1584                         _ => {},
1585                 }
1586         }
1587
1588         fn write_conversion_inline_intern<W: std::io::Write,
1589                         LP: Fn(&str, bool, bool) -> Option<String>, DL: Fn(&mut W, &DeclType, &str, bool, bool), SC: Fn(bool, Option<&str>) -> String>
1590                         (&self, w: &mut W, t: &syn::Type, generics: Option<&GenericTypes>, is_ref: bool, is_mut: bool, ptr_for_ref: bool,
1591                          tupleconv: &str, prefix: bool, sliceconv: SC, path_lookup: LP, decl_lookup: DL) {
1592                 match t {
1593                         syn::Type::Reference(r) => {
1594                                 self.write_conversion_inline_intern(w, &*r.elem, generics, true, r.mutability.is_some(),
1595                                         ptr_for_ref, tupleconv, prefix, sliceconv, path_lookup, decl_lookup);
1596                         },
1597                         syn::Type::Path(p) => {
1598                                 if p.qself.is_some() {
1599                                         unimplemented!();
1600                                 }
1601
1602                                 let resolved_path = self.resolve_path(&p.path, generics);
1603                                 if let Some(aliased_type) = self.crate_types.type_aliases.get(&resolved_path) {
1604                                         return self.write_conversion_inline_intern(w, aliased_type, None, is_ref, is_mut, ptr_for_ref, tupleconv, prefix, sliceconv, path_lookup, decl_lookup);
1605                                 } else if self.is_primitive(&resolved_path) {
1606                                         if is_ref && prefix {
1607                                                 write!(w, "*").unwrap();
1608                                         }
1609                                 } else if let Some(c_type) = path_lookup(&resolved_path, is_ref, ptr_for_ref) {
1610                                         write!(w, "{}", c_type).unwrap();
1611                                 } else if self.crate_types.opaques.get(&resolved_path).is_some() {
1612                                         decl_lookup(w, &DeclType::StructImported, &resolved_path, is_ref, is_mut);
1613                                 } else if self.crate_types.mirrored_enums.get(&resolved_path).is_some() {
1614                                         decl_lookup(w, &DeclType::MirroredEnum, &resolved_path, is_ref, is_mut);
1615                                 } else if let Some(t) = self.crate_types.traits.get(&resolved_path) {
1616                                         decl_lookup(w, &DeclType::Trait(t), &resolved_path, is_ref, is_mut);
1617                                 } else if let Some(ident) = single_ident_generic_path_to_ident(&p.path) {
1618                                         if let Some(decl_type) = self.types.maybe_resolve_declared(ident) {
1619                                                 decl_lookup(w, decl_type, &self.maybe_resolve_ident(ident).unwrap(), is_ref, is_mut);
1620                                         } else { unimplemented!(); }
1621                                 } else { unimplemented!(); }
1622                         },
1623                         syn::Type::Array(a) => {
1624                                 // We assume all arrays contain only [int_literal; X]s.
1625                                 // This may result in some outputs not compiling.
1626                                 if let syn::Expr::Lit(l) = &a.len {
1627                                         if let syn::Lit::Int(i) = &l.lit {
1628                                                 write!(w, "{}", path_lookup(&format!("[u8; {}]", i.base10_digits()), is_ref, ptr_for_ref).unwrap()).unwrap();
1629                                         } else { unimplemented!(); }
1630                                 } else { unimplemented!(); }
1631                         },
1632                         syn::Type::Slice(s) => {
1633                                 // We assume all slices contain only literals or references.
1634                                 // This may result in some outputs not compiling.
1635                                 if let syn::Type::Path(p) = &*s.elem {
1636                                         let resolved = self.resolve_path(&p.path, generics);
1637                                         assert!(self.is_primitive(&resolved));
1638                                         write!(w, "{}", path_lookup("[u8]", is_ref, ptr_for_ref).unwrap()).unwrap();
1639                                 } else if let syn::Type::Reference(r) = &*s.elem {
1640                                         if let syn::Type::Path(p) = &*r.elem {
1641                                                 write!(w, "{}", sliceconv(self.c_type_has_inner_from_path(&self.resolve_path(&p.path, generics)), None)).unwrap();
1642                                         } else { unimplemented!(); }
1643                                 } else if let syn::Type::Tuple(t) = &*s.elem {
1644                                         assert!(!t.elems.is_empty());
1645                                         if prefix {
1646                                                 write!(w, "{}", sliceconv(false, None)).unwrap();
1647                                         } else {
1648                                                 let mut needs_map = false;
1649                                                 for e in t.elems.iter() {
1650                                                         if let syn::Type::Reference(_) = e {
1651                                                                 needs_map = true;
1652                                                         }
1653                                                 }
1654                                                 if needs_map {
1655                                                         let mut map_str = Vec::new();
1656                                                         write!(&mut map_str, ".map(|(").unwrap();
1657                                                         for i in 0..t.elems.len() {
1658                                                                 write!(&mut map_str, "{}{}", if i != 0 { ", " } else { "" }, ('a' as u8 + i as u8) as char).unwrap();
1659                                                         }
1660                                                         write!(&mut map_str, ")| (").unwrap();
1661                                                         for (idx, e) in t.elems.iter().enumerate() {
1662                                                                 if let syn::Type::Reference(_) = e {
1663                                                                         write!(&mut map_str, "{}{}", if idx != 0 { ", " } else { "" }, (idx as u8 + 'a' as u8) as char).unwrap();
1664                                                                 } else if let syn::Type::Path(_) = e {
1665                                                                         write!(&mut map_str, "{}*{}", if idx != 0 { ", " } else { "" }, (idx as u8 + 'a' as u8) as char).unwrap();
1666                                                                 } else { unimplemented!(); }
1667                                                         }
1668                                                         write!(&mut map_str, "))").unwrap();
1669                                                         write!(w, "{}", sliceconv(false, Some(&String::from_utf8(map_str).unwrap()))).unwrap();
1670                                                 } else {
1671                                                         write!(w, "{}", sliceconv(false, None)).unwrap();
1672                                                 }
1673                                         }
1674                                 } else { unimplemented!(); }
1675                         },
1676                         syn::Type::Tuple(t) => {
1677                                 if t.elems.is_empty() {
1678                                         // cbindgen has poor support for (), see, eg https://github.com/eqrion/cbindgen/issues/527
1679                                         // so work around it by just pretending its a 0u8
1680                                         write!(w, "{}", tupleconv).unwrap();
1681                                 } else {
1682                                         if prefix { write!(w, "local_").unwrap(); }
1683                                 }
1684                         },
1685                         _ => unimplemented!(),
1686                 }
1687         }
1688
1689         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) {
1690                 self.write_conversion_inline_intern(w, t, generics, is_ref, false, ptr_for_ref, "0u8 /*", true, |_, _| "local_".to_owned(),
1691                                 |a, b, c| self.to_c_conversion_inline_prefix_from_path(a, b, c),
1692                                 |w, decl_type, decl_path, is_ref, _is_mut| {
1693                                         match decl_type {
1694                                                 DeclType::MirroredEnum if is_ref && ptr_for_ref => write!(w, "crate::{}::from_native(", decl_path).unwrap(),
1695                                                 DeclType::MirroredEnum if is_ref => write!(w, "&crate::{}::from_native(", decl_path).unwrap(),
1696                                                 DeclType::MirroredEnum => write!(w, "crate::{}::native_into(", decl_path).unwrap(),
1697                                                 DeclType::EnumIgnored|DeclType::StructImported if is_ref && ptr_for_ref && from_ptr =>
1698                                                         write!(w, "crate::{} {{ inner: unsafe {{ (", decl_path).unwrap(),
1699                                                 DeclType::EnumIgnored|DeclType::StructImported if is_ref && ptr_for_ref =>
1700                                                         write!(w, "crate::{} {{ inner: unsafe {{ ( (&(*", decl_path).unwrap(),
1701                                                 DeclType::EnumIgnored|DeclType::StructImported if is_ref =>
1702                                                         write!(w, "&crate::{} {{ inner: unsafe {{ (", decl_path).unwrap(),
1703                                                 DeclType::EnumIgnored|DeclType::StructImported if !is_ref && from_ptr =>
1704                                                         write!(w, "crate::{} {{ inner: ", decl_path).unwrap(),
1705                                                 DeclType::EnumIgnored|DeclType::StructImported if !is_ref =>
1706                                                         write!(w, "crate::{} {{ inner: Box::into_raw(Box::new(", decl_path).unwrap(),
1707                                                 DeclType::Trait(_) if is_ref => write!(w, "").unwrap(),
1708                                                 DeclType::Trait(_) if !is_ref => {},
1709                                                 _ => panic!("{:?}", decl_path),
1710                                         }
1711                                 });
1712         }
1713         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) {
1714                 self.write_to_c_conversion_inline_prefix_inner(w, t, generics, false, ptr_for_ref, false);
1715         }
1716         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) {
1717                 self.write_conversion_inline_intern(w, t, generics, is_ref, false, ptr_for_ref, "*/", false, |_, _| ".into()".to_owned(),
1718                                 |a, b, c| self.to_c_conversion_inline_suffix_from_path(a, b, c),
1719                                 |w, decl_type, _full_path, is_ref, _is_mut| match decl_type {
1720                                         DeclType::MirroredEnum => write!(w, ")").unwrap(),
1721                                         DeclType::EnumIgnored|DeclType::StructImported if is_ref && ptr_for_ref && from_ptr =>
1722                                                 write!(w, " as *const _) as *mut _ }}, is_owned: false }}").unwrap(),
1723                                         DeclType::EnumIgnored|DeclType::StructImported if is_ref && ptr_for_ref =>
1724                                                 write!(w, ") as *const _) as *mut _) }}, is_owned: false }}").unwrap(),
1725                                         DeclType::EnumIgnored|DeclType::StructImported if is_ref =>
1726                                                 write!(w, " as *const _) as *mut _ }}, is_owned: false }}").unwrap(),
1727                                         DeclType::EnumIgnored|DeclType::StructImported if !is_ref && from_ptr =>
1728                                                 write!(w, ", is_owned: true }}").unwrap(),
1729                                         DeclType::EnumIgnored|DeclType::StructImported if !is_ref => write!(w, ")), is_owned: true }}").unwrap(),
1730                                         DeclType::Trait(_) if is_ref => {},
1731                                         DeclType::Trait(_) => {
1732                                                 // This is used when we're converting a concrete Rust type into a C trait
1733                                                 // for use when a Rust trait method returns an associated type.
1734                                                 // Because all of our C traits implement From<RustTypesImplementingTraits>
1735                                                 // we can just call .into() here and be done.
1736                                                 write!(w, ".into()").unwrap()
1737                                         },
1738                                         _ => unimplemented!(),
1739                                 });
1740         }
1741         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) {
1742                 self.write_to_c_conversion_inline_suffix_inner(w, t, generics, false, ptr_for_ref, false);
1743         }
1744
1745         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) {
1746                 self.write_conversion_inline_intern(w, t, generics, is_ref, false, false, "() /*", true, |_, _| "&local_".to_owned(),
1747                                 |a, b, _c| self.from_c_conversion_prefix_from_path(a, b),
1748                                 |w, decl_type, _full_path, is_ref, is_mut| match decl_type {
1749                                         DeclType::StructImported if is_ref && ptr_for_ref => write!(w, "unsafe {{ &*(*").unwrap(),
1750                                         DeclType::StructImported if is_mut && is_ref => write!(w, "unsafe {{ &mut *").unwrap(),
1751                                         DeclType::StructImported if is_ref => write!(w, "unsafe {{ &*").unwrap(),
1752                                         DeclType::StructImported if !is_ref => write!(w, "*unsafe {{ Box::from_raw(").unwrap(),
1753                                         DeclType::MirroredEnum if is_ref => write!(w, "&").unwrap(),
1754                                         DeclType::MirroredEnum => {},
1755                                         DeclType::Trait(_) => {},
1756                                         _ => unimplemented!(),
1757                                 });
1758         }
1759         pub fn write_from_c_conversion_prefix<W: std::io::Write>(&self, w: &mut W, t: &syn::Type, generics: Option<&GenericTypes>) {
1760                 self.write_from_c_conversion_prefix_inner(w, t, generics, false, false);
1761         }
1762         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) {
1763                 self.write_conversion_inline_intern(w, t, generics, is_ref, false, false, "*/", false,
1764                                 |has_inner, map_str_opt| match (has_inner, map_str_opt) {
1765                                         (false, Some(map_str)) => format!(".iter(){}.collect::<Vec<_>>()[..]", map_str),
1766                                         (false, None) => ".iter().collect::<Vec<_>>()[..]".to_owned(),
1767                                         (true, None) => "[..]".to_owned(),
1768                                         (true, Some(_)) => unreachable!(),
1769                                 },
1770                                 |a, b, _c| self.from_c_conversion_suffix_from_path(a, b),
1771                                 |w, decl_type, _full_path, is_ref, _is_mut| match decl_type {
1772                                         DeclType::StructImported if is_ref && ptr_for_ref => write!(w, ").inner }}").unwrap(),
1773                                         DeclType::StructImported if is_ref => write!(w, ".inner }}").unwrap(),
1774                                         DeclType::StructImported if !is_ref => write!(w, ".take_inner()) }}").unwrap(),
1775                                         DeclType::MirroredEnum if is_ref => write!(w, ".to_native()").unwrap(),
1776                                         DeclType::MirroredEnum => write!(w, ".into_native()").unwrap(),
1777                                         DeclType::Trait(_) => {},
1778                                         _ => unimplemented!(),
1779                                 });
1780         }
1781         pub fn write_from_c_conversion_suffix<W: std::io::Write>(&self, w: &mut W, t: &syn::Type, generics: Option<&GenericTypes>) {
1782                 self.write_from_c_conversion_suffix_inner(w, t, generics, false, false);
1783         }
1784         // Note that compared to the above conversion functions, the following two are generally
1785         // significantly undertested:
1786         pub fn write_from_c_conversion_to_ref_prefix<W: std::io::Write>(&self, w: &mut W, t: &syn::Type, generics: Option<&GenericTypes>) {
1787                 self.write_conversion_inline_intern(w, t, generics, false, false, false, "() /*", true, |_, _| "&local_".to_owned(),
1788                                 |a, b, _c| {
1789                                         if let Some(conv) = self.from_c_conversion_prefix_from_path(a, b) {
1790                                                 Some(format!("&{}", conv))
1791                                         } else { None }
1792                                 },
1793                                 |w, decl_type, _full_path, is_ref, _is_mut| match decl_type {
1794                                         DeclType::StructImported if !is_ref => write!(w, "unsafe {{ &*").unwrap(),
1795                                         _ => unimplemented!(),
1796                                 });
1797         }
1798         pub fn write_from_c_conversion_to_ref_suffix<W: std::io::Write>(&self, w: &mut W, t: &syn::Type, generics: Option<&GenericTypes>) {
1799                 self.write_conversion_inline_intern(w, t, generics, false, false, false, "*/", false,
1800                                 |has_inner, map_str_opt| match (has_inner, map_str_opt) {
1801                                         (false, Some(map_str)) => format!(".iter(){}.collect::<Vec<_>>()[..]", map_str),
1802                                         (false, None) => ".iter().collect::<Vec<_>>()[..]".to_owned(),
1803                                         (true, None) => "[..]".to_owned(),
1804                                         (true, Some(_)) => unreachable!(),
1805                                 },
1806                                 |a, b, _c| self.from_c_conversion_suffix_from_path(a, b),
1807                                 |w, decl_type, _full_path, is_ref, _is_mut| match decl_type {
1808                                         DeclType::StructImported if !is_ref => write!(w, ".inner }}").unwrap(),
1809                                         _ => unimplemented!(),
1810                                 });
1811         }
1812
1813         fn write_conversion_new_var_intern<'b, W: std::io::Write,
1814                 LP: Fn(&str, bool) -> Option<(&str, &str)>,
1815                 LC: Fn(&str, bool, Option<&syn::Type>, &syn::Ident, &str) ->  Option<(&'b str, Vec<(String, String)>, &'b str, ContainerPrefixLocation)>,
1816                 VP: Fn(&mut W, &syn::Type, Option<&GenericTypes>, bool, bool, bool),
1817                 VS: Fn(&mut W, &syn::Type, Option<&GenericTypes>, bool, bool, bool)>
1818                         (&self, w: &mut W, ident: &syn::Ident, var: &str, t: &syn::Type, generics: Option<&GenericTypes>,
1819                          mut is_ref: bool, mut ptr_for_ref: bool, to_c: bool,
1820                          path_lookup: &LP, container_lookup: &LC, var_prefix: &VP, var_suffix: &VS) -> bool {
1821
1822                 macro_rules! convert_container {
1823                         ($container_type: expr, $args_len: expr, $args_iter: expr) => { {
1824                                 // For slices (and Options), we refuse to directly map them as is_ref when they
1825                                 // aren't opaque types containing an inner pointer. This is due to the fact that,
1826                                 // in both cases, the actual higher-level type is non-is_ref.
1827                                 let ty_has_inner = if $args_len == 1 {
1828                                         let ty = $args_iter().next().unwrap();
1829                                         if $container_type == "Slice" && to_c {
1830                                                 // "To C ptr_for_ref" means "return the regular object with is_owned
1831                                                 // set to false", which is totally what we want in a slice if we're about to
1832                                                 // set ty_has_inner.
1833                                                 ptr_for_ref = true;
1834                                         }
1835                                         if let syn::Type::Reference(t) = ty {
1836                                                 if let syn::Type::Path(p) = &*t.elem {
1837                                                         self.c_type_has_inner_from_path(&self.resolve_path(&p.path, generics))
1838                                                 } else { false }
1839                                         } else if let syn::Type::Path(p) = ty {
1840                                                 self.c_type_has_inner_from_path(&self.resolve_path(&p.path, generics))
1841                                         } else { false }
1842                                 } else { true };
1843
1844                                 // Options get a bunch of special handling, since in general we map Option<>al
1845                                 // types into the same C type as non-Option-wrapped types. This ends up being
1846                                 // pretty manual here and most of the below special-cases are for Options.
1847                                 let mut needs_ref_map = false;
1848                                 let mut only_contained_type = None;
1849                                 let mut only_contained_has_inner = false;
1850                                 let mut contains_slice = false;
1851                                 if $args_len == 1 {
1852                                         only_contained_has_inner = ty_has_inner;
1853                                         let arg = $args_iter().next().unwrap();
1854                                         if let syn::Type::Reference(t) = arg {
1855                                                 only_contained_type = Some(&*t.elem);
1856                                                 if let syn::Type::Path(_) = &*t.elem {
1857                                                         is_ref = true;
1858                                                 } else if let syn::Type::Slice(_) = &*t.elem {
1859                                                         contains_slice = true;
1860                                                 } else { return false; }
1861                                                 // If the inner element contains an inner pointer, we will just use that,
1862                                                 // avoiding the need to map elements to references. Otherwise we'll need to
1863                                                 // do an extra mapping step.
1864                                                 needs_ref_map = !only_contained_has_inner;
1865                                         } else {
1866                                                 only_contained_type = Some(&arg);
1867                                         }
1868                                 }
1869
1870                                 if let Some((prefix, conversions, suffix, prefix_location)) = container_lookup(&$container_type, is_ref && ty_has_inner, only_contained_type, ident, var) {
1871                                         assert_eq!(conversions.len(), $args_len);
1872                                         write!(w, "let mut local_{}{} = ", ident, if !to_c && needs_ref_map {"_base"} else { "" }).unwrap();
1873                                         if prefix_location == ContainerPrefixLocation::OutsideConv {
1874                                                 var_prefix(w, $args_iter().next().unwrap(), generics, is_ref, ptr_for_ref, true);
1875                                         }
1876                                         write!(w, "{}{}", prefix, var).unwrap();
1877
1878                                         for ((pfx, var_name), (idx, ty)) in conversions.iter().zip($args_iter().enumerate()) {
1879                                                 let mut var = std::io::Cursor::new(Vec::new());
1880                                                 write!(&mut var, "{}", var_name).unwrap();
1881                                                 let var_access = String::from_utf8(var.into_inner()).unwrap();
1882
1883                                                 let conv_ty = if needs_ref_map { only_contained_type.as_ref().unwrap() } else { ty };
1884
1885                                                 write!(w, "{} {{ ", pfx).unwrap();
1886                                                 let new_var_name = format!("{}_{}", ident, idx);
1887                                                 let new_var = self.write_conversion_new_var_intern(w, &format_ident!("{}", new_var_name),
1888                                                                 &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);
1889                                                 if new_var { write!(w, " ").unwrap(); }
1890
1891                                                 if prefix_location == ContainerPrefixLocation::PerConv {
1892                                                         var_prefix(w, conv_ty, generics, is_ref && ty_has_inner, ptr_for_ref, false);
1893                                                 } else if !is_ref && !needs_ref_map && to_c && only_contained_has_inner {
1894                                                         write!(w, "Box::into_raw(Box::new(").unwrap();
1895                                                 }
1896
1897                                                 write!(w, "{}{}", if contains_slice { "local_" } else { "" }, if new_var { new_var_name } else { var_access }).unwrap();
1898                                                 if prefix_location == ContainerPrefixLocation::PerConv {
1899                                                         var_suffix(w, conv_ty, generics, is_ref && ty_has_inner, ptr_for_ref, false);
1900                                                 } else if !is_ref && !needs_ref_map && to_c && only_contained_has_inner {
1901                                                         write!(w, "))").unwrap();
1902                                                 }
1903                                                 write!(w, " }}").unwrap();
1904                                         }
1905                                         write!(w, "{}", suffix).unwrap();
1906                                         if prefix_location == ContainerPrefixLocation::OutsideConv {
1907                                                 var_suffix(w, $args_iter().next().unwrap(), generics, is_ref, ptr_for_ref, true);
1908                                         }
1909                                         write!(w, ";").unwrap();
1910                                         if !to_c && needs_ref_map {
1911                                                 write!(w, " let mut local_{} = local_{}_base.as_ref()", ident, ident).unwrap();
1912                                                 if contains_slice {
1913                                                         write!(w, ".map(|a| &a[..])").unwrap();
1914                                                 }
1915                                                 write!(w, ";").unwrap();
1916                                         }
1917                                         return true;
1918                                 }
1919                         } }
1920                 }
1921
1922                 match t {
1923                         syn::Type::Reference(r) => {
1924                                 if let syn::Type::Slice(_) = &*r.elem {
1925                                         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)
1926                                 } else {
1927                                         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)
1928                                 }
1929                         },
1930                         syn::Type::Path(p) => {
1931                                 if p.qself.is_some() {
1932                                         unimplemented!();
1933                                 }
1934                                 let resolved_path = self.resolve_path(&p.path, generics);
1935                                 if let Some(aliased_type) = self.crate_types.type_aliases.get(&resolved_path) {
1936                                         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);
1937                                 }
1938                                 if self.is_known_container(&resolved_path, is_ref) || self.is_path_transparent_container(&p.path, generics, is_ref) {
1939                                         if let syn::PathArguments::AngleBracketed(args) = &p.path.segments.iter().next().unwrap().arguments {
1940                                                 convert_container!(resolved_path, args.args.len(), || args.args.iter().map(|arg| {
1941                                                         if let syn::GenericArgument::Type(ty) = arg {
1942                                                                 ty
1943                                                         } else { unimplemented!(); }
1944                                                 }));
1945                                         } else { unimplemented!(); }
1946                                 }
1947                                 if self.is_primitive(&resolved_path) {
1948                                         false
1949                                 } else if let Some(ty_ident) = single_ident_generic_path_to_ident(&p.path) {
1950                                         if let Some((prefix, suffix)) = path_lookup(&resolved_path, is_ref) {
1951                                                 write!(w, "let mut local_{} = {}{}{};", ident, prefix, var, suffix).unwrap();
1952                                                 true
1953                                         } else if self.types.maybe_resolve_declared(ty_ident).is_some() {
1954                                                 false
1955                                         } else { false }
1956                                 } else { false }
1957                         },
1958                         syn::Type::Array(_) => {
1959                                 // We assume all arrays contain only primitive types.
1960                                 // This may result in some outputs not compiling.
1961                                 false
1962                         },
1963                         syn::Type::Slice(s) => {
1964                                 if let syn::Type::Path(p) = &*s.elem {
1965                                         let resolved = self.resolve_path(&p.path, generics);
1966                                         assert!(self.is_primitive(&resolved));
1967                                         let slice_path = format!("[{}]", resolved);
1968                                         if let Some((prefix, suffix)) = path_lookup(&slice_path, true) {
1969                                                 write!(w, "let mut local_{} = {}{}{};", ident, prefix, var, suffix).unwrap();
1970                                                 true
1971                                         } else { false }
1972                                 } else if let syn::Type::Reference(ty) = &*s.elem {
1973                                         let tyref = [&*ty.elem];
1974                                         is_ref = true;
1975                                         convert_container!("Slice", 1, || tyref.iter().map(|t| *t));
1976                                         unimplemented!("convert_container should return true as container_lookup should succeed for slices");
1977                                 } else if let syn::Type::Tuple(t) = &*s.elem {
1978                                         // When mapping into a temporary new var, we need to own all the underlying objects.
1979                                         // Thus, we drop any references inside the tuple and convert with non-reference types.
1980                                         let mut elems = syn::punctuated::Punctuated::new();
1981                                         for elem in t.elems.iter() {
1982                                                 if let syn::Type::Reference(r) = elem {
1983                                                         elems.push((*r.elem).clone());
1984                                                 } else {
1985                                                         elems.push(elem.clone());
1986                                                 }
1987                                         }
1988                                         let ty = [syn::Type::Tuple(syn::TypeTuple {
1989                                                 paren_token: t.paren_token, elems
1990                                         })];
1991                                         is_ref = false;
1992                                         ptr_for_ref = true;
1993                                         convert_container!("Slice", 1, || ty.iter());
1994                                         unimplemented!("convert_container should return true as container_lookup should succeed for slices");
1995                                 } else { unimplemented!() }
1996                         },
1997                         syn::Type::Tuple(t) => {
1998                                 if !t.elems.is_empty() {
1999                                         // We don't (yet) support tuple elements which cannot be converted inline
2000                                         write!(w, "let (").unwrap();
2001                                         for idx in 0..t.elems.len() {
2002                                                 if idx != 0 { write!(w, ", ").unwrap(); }
2003                                                 write!(w, "{} orig_{}_{}", if is_ref { "ref" } else { "mut" }, ident, idx).unwrap();
2004                                         }
2005                                         write!(w, ") = {}{}; ", var, if !to_c { ".to_rust()" } else { "" }).unwrap();
2006                                         // Like other template types, tuples are always mapped as their non-ref
2007                                         // versions for types which have different ref mappings. Thus, we convert to
2008                                         // non-ref versions and handle opaque types with inner pointers manually.
2009                                         for (idx, elem) in t.elems.iter().enumerate() {
2010                                                 if let syn::Type::Path(p) = elem {
2011                                                         let v_name = format!("orig_{}_{}", ident, idx);
2012                                                         let tuple_elem_ident = format_ident!("{}", &v_name);
2013                                                         if self.write_conversion_new_var_intern(w, &tuple_elem_ident, &v_name, elem, generics,
2014                                                                         false, ptr_for_ref, to_c,
2015                                                                         path_lookup, container_lookup, var_prefix, var_suffix) {
2016                                                                 write!(w, " ").unwrap();
2017                                                                 // Opaque types with inner pointers shouldn't ever create new stack
2018                                                                 // variables, so we don't handle it and just assert that it doesn't
2019                                                                 // here.
2020                                                                 assert!(!self.c_type_has_inner_from_path(&self.resolve_path(&p.path, generics)));
2021                                                         }
2022                                                 }
2023                                         }
2024                                         write!(w, "let mut local_{} = (", ident).unwrap();
2025                                         for (idx, elem) in t.elems.iter().enumerate() {
2026                                                 let ty_has_inner = {
2027                                                                 if to_c {
2028                                                                         // "To C ptr_for_ref" means "return the regular object with
2029                                                                         // is_owned set to false", which is totally what we want
2030                                                                         // if we're about to set ty_has_inner.
2031                                                                         ptr_for_ref = true;
2032                                                                 }
2033                                                                 if let syn::Type::Reference(t) = elem {
2034                                                                         if let syn::Type::Path(p) = &*t.elem {
2035                                                                                 self.c_type_has_inner_from_path(&self.resolve_path(&p.path, generics))
2036                                                                         } else { false }
2037                                                                 } else if let syn::Type::Path(p) = elem {
2038                                                                         self.c_type_has_inner_from_path(&self.resolve_path(&p.path, generics))
2039                                                                 } else { false }
2040                                                         };
2041                                                 if idx != 0 { write!(w, ", ").unwrap(); }
2042                                                 var_prefix(w, elem, generics, is_ref && ty_has_inner, ptr_for_ref, false);
2043                                                 if is_ref && ty_has_inner {
2044                                                         // For ty_has_inner, the regular var_prefix mapping will take a
2045                                                         // reference, so deref once here to make sure we keep the original ref.
2046                                                         write!(w, "*").unwrap();
2047                                                 }
2048                                                 write!(w, "orig_{}_{}", ident, idx).unwrap();
2049                                                 if is_ref && !ty_has_inner {
2050                                                         // If we don't have an inner variable's reference to maintain, just
2051                                                         // hope the type is Clonable and use that.
2052                                                         write!(w, ".clone()").unwrap();
2053                                                 }
2054                                                 var_suffix(w, elem, generics, is_ref && ty_has_inner, ptr_for_ref, false);
2055                                         }
2056                                         write!(w, "){};", if to_c { ".into()" } else { "" }).unwrap();
2057                                         true
2058                                 } else { false }
2059                         },
2060                         _ => unimplemented!(),
2061                 }
2062         }
2063
2064         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 {
2065                 self.write_conversion_new_var_intern(w, ident, var_access, t, generics, false, ptr_for_ref, true,
2066                         &|a, b| self.to_c_conversion_new_var_from_path(a, b),
2067                         &|a, b, c, d, e| self.to_c_conversion_container_new_var(generics, a, b, c, d, e),
2068                         // We force ptr_for_ref here since we can't generate a ref on one line and use it later
2069                         &|a, b, c, d, e, f| self.write_to_c_conversion_inline_prefix_inner(a, b, c, d, e, f),
2070                         &|a, b, c, d, e, f| self.write_to_c_conversion_inline_suffix_inner(a, b, c, d, e, f))
2071         }
2072         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 {
2073                 self.write_to_c_conversion_new_var_inner(w, ident, &format!("{}", ident), t, generics, ptr_for_ref)
2074         }
2075         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 {
2076                 self.write_conversion_new_var_intern(w, ident, &format!("{}", ident), t, generics, false, false, false,
2077                         &|a, b| self.from_c_conversion_new_var_from_path(a, b),
2078                         &|a, b, c, d, e| self.from_c_conversion_container_new_var(generics, a, b, c, d, e),
2079                         // We force ptr_for_ref here since we can't generate a ref on one line and use it later
2080                         &|a, b, c, d, e, _f| self.write_from_c_conversion_prefix_inner(a, b, c, d, e),
2081                         &|a, b, c, d, e, _f| self.write_from_c_conversion_suffix_inner(a, b, c, d, e))
2082         }
2083
2084         // ******************************************************
2085         // *** C Container Type Equivalent and alias Printing ***
2086         // ******************************************************
2087
2088         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 {
2089                 for (idx, t) in args.enumerate() {
2090                         if idx != 0 {
2091                                 write!(w, ", ").unwrap();
2092                         }
2093                         if let syn::Type::Reference(r_arg) = t {
2094                                 assert!(!is_ref); // We don't currently support outer reference types for non-primitive inners
2095
2096                                 if !self.write_c_type_intern(w, &*r_arg.elem, generics, false, false, false) { return false; }
2097
2098                                 // While write_c_type_intern, above is correct, we don't want to blindly convert a
2099                                 // reference to something stupid, so check that the container is either opaque or a
2100                                 // predefined type (currently only Transaction).
2101                                 if let syn::Type::Path(p_arg) = &*r_arg.elem {
2102                                         let resolved = self.resolve_path(&p_arg.path, generics);
2103                                         assert!(self.crate_types.opaques.get(&resolved).is_some() ||
2104                                                         self.c_type_from_path(&resolved, true, true).is_some(), "Template generics should be opaque or have a predefined mapping");
2105                                 } else { unimplemented!(); }
2106                         } else if let syn::Type::Path(p_arg) = t {
2107                                 if let Some(resolved) = self.maybe_resolve_path(&p_arg.path, generics) {
2108                                         if !self.is_primitive(&resolved) {
2109                                                 assert!(!is_ref); // We don't currently support outer reference types for non-primitive inners
2110                                         }
2111                                 } else {
2112                                         assert!(!is_ref); // We don't currently support outer reference types for non-primitive inners
2113                                 }
2114                                 if !self.write_c_type_intern(w, t, generics, false, false, false) { return false; }
2115                         } else {
2116                                 assert!(!is_ref); // We don't currently support outer reference types for non-primitive inners
2117                                 if !self.write_c_type_intern(w, t, generics, false, false, false) { return false; }
2118                         }
2119                 }
2120                 true
2121         }
2122         fn check_create_container(&self, mangled_container: String, container_type: &str, args: Vec<&syn::Type>, generics: Option<&GenericTypes>, is_ref: bool) -> bool {
2123                 if !self.crate_types.templates_defined.borrow().get(&mangled_container).is_some() {
2124                         let mut created_container: Vec<u8> = Vec::new();
2125
2126                         if container_type == "Result" {
2127                                 let mut a_ty: Vec<u8> = Vec::new();
2128                                 if let syn::Type::Tuple(tup) = args.iter().next().unwrap() {
2129                                         if tup.elems.is_empty() {
2130                                                 write!(&mut a_ty, "()").unwrap();
2131                                         } else {
2132                                                 if !self.write_template_generics(&mut a_ty, &mut args.iter().map(|t| *t).take(1), generics, is_ref) { return false; }
2133                                         }
2134                                 } else {
2135                                         if !self.write_template_generics(&mut a_ty, &mut args.iter().map(|t| *t).take(1), generics, is_ref) { return false; }
2136                                 }
2137
2138                                 let mut b_ty: Vec<u8> = Vec::new();
2139                                 if let syn::Type::Tuple(tup) = args.iter().skip(1).next().unwrap() {
2140                                         if tup.elems.is_empty() {
2141                                                 write!(&mut b_ty, "()").unwrap();
2142                                         } else {
2143                                                 if !self.write_template_generics(&mut b_ty, &mut args.iter().map(|t| *t).skip(1), generics, is_ref) { return false; }
2144                                         }
2145                                 } else {
2146                                         if !self.write_template_generics(&mut b_ty, &mut args.iter().map(|t| *t).skip(1), generics, is_ref) { return false; }
2147                                 }
2148
2149                                 let ok_str = String::from_utf8(a_ty).unwrap();
2150                                 let err_str = String::from_utf8(b_ty).unwrap();
2151                                 let is_clonable = self.is_clonable(&ok_str) && self.is_clonable(&err_str);
2152                                 write_result_block(&mut created_container, &mangled_container, &ok_str, &err_str, is_clonable);
2153                                 if is_clonable {
2154                                         self.crate_types.set_clonable(Self::generated_container_path().to_owned() + "::" + &mangled_container);
2155                                 }
2156                         } else if container_type == "Vec" {
2157                                 let mut a_ty: Vec<u8> = Vec::new();
2158                                 if !self.write_template_generics(&mut a_ty, &mut args.iter().map(|t| *t), generics, is_ref) { return false; }
2159                                 let ty = String::from_utf8(a_ty).unwrap();
2160                                 let is_clonable = self.is_clonable(&ty);
2161                                 write_vec_block(&mut created_container, &mangled_container, &ty, is_clonable);
2162                                 if is_clonable {
2163                                         self.crate_types.set_clonable(Self::generated_container_path().to_owned() + "::" + &mangled_container);
2164                                 }
2165                         } else if container_type.ends_with("Tuple") {
2166                                 let mut tuple_args = Vec::new();
2167                                 let mut is_clonable = true;
2168                                 for arg in args.iter() {
2169                                         let mut ty: Vec<u8> = Vec::new();
2170                                         if !self.write_template_generics(&mut ty, &mut [arg].iter().map(|t| **t), generics, is_ref) { return false; }
2171                                         let ty_str = String::from_utf8(ty).unwrap();
2172                                         if !self.is_clonable(&ty_str) {
2173                                                 is_clonable = false;
2174                                         }
2175                                         tuple_args.push(ty_str);
2176                                 }
2177                                 write_tuple_block(&mut created_container, &mangled_container, &tuple_args, is_clonable);
2178                                 if is_clonable {
2179                                         self.crate_types.set_clonable(Self::generated_container_path().to_owned() + "::" + &mangled_container);
2180                                 }
2181                         } else if container_type == "Option" {
2182                                 let mut a_ty: Vec<u8> = Vec::new();
2183                                 if !self.write_template_generics(&mut a_ty, &mut args.iter().map(|t| *t), generics, is_ref) { return false; }
2184                                 let ty = String::from_utf8(a_ty).unwrap();
2185                                 let is_clonable = self.is_clonable(&ty);
2186                                 write_option_block(&mut created_container, &mangled_container, &ty, is_clonable);
2187                                 if is_clonable {
2188                                         self.crate_types.set_clonable(Self::generated_container_path().to_owned() + "::" + &mangled_container);
2189                                 }
2190                         } else {
2191                                 unreachable!();
2192                         }
2193                         self.crate_types.write_new_template(mangled_container.clone(), true, &created_container);
2194                 }
2195                 true
2196         }
2197         fn path_to_generic_args(path: &syn::Path) -> Vec<&syn::Type> {
2198                 if let syn::PathArguments::AngleBracketed(args) = &path.segments.iter().next().unwrap().arguments {
2199                         args.args.iter().map(|gen| if let syn::GenericArgument::Type(t) = gen { t } else { unimplemented!() }).collect()
2200                 } else { unimplemented!(); }
2201         }
2202         fn write_c_mangled_container_path_intern<W: std::io::Write>
2203                         (&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 {
2204                 let mut mangled_type: Vec<u8> = Vec::new();
2205                 if !self.is_transparent_container(ident, is_ref, args.iter().map(|a| *a)) {
2206                         write!(w, "C{}_", ident).unwrap();
2207                         write!(mangled_type, "C{}_", ident).unwrap();
2208                 } else { assert_eq!(args.len(), 1); }
2209                 for arg in args.iter() {
2210                         macro_rules! write_path {
2211                                 ($p_arg: expr, $extra_write: expr) => {
2212                                         if let Some(subtype) = self.maybe_resolve_path(&$p_arg.path, generics) {
2213                                                 if self.is_transparent_container(ident, is_ref, args.iter().map(|a| *a)) {
2214                                                         if !in_type {
2215                                                                 if self.c_type_has_inner_from_path(&subtype) {
2216                                                                         if !self.write_c_path_intern(w, &$p_arg.path, generics, is_ref, is_mut, ptr_for_ref) { return false; }
2217                                                                 } else {
2218                                                                         if let Some(arr_ty) = self.is_real_type_array(&subtype) {
2219                                                                                 if !self.write_c_type_intern(w, &arr_ty, generics, false, true, false) { return false; }
2220                                                                         } else {
2221                                                                                 // Option<T> needs to be converted to a *mut T, ie mut ptr-for-ref
2222                                                                                 if !self.write_c_path_intern(w, &$p_arg.path, generics, true, true, true) { return false; }
2223                                                                         }
2224                                                                 }
2225                                                         } else {
2226                                                                 write!(w, "{}", $p_arg.path.segments.last().unwrap().ident).unwrap();
2227                                                         }
2228                                                 } else if self.is_known_container(&subtype, is_ref) || self.is_path_transparent_container(&$p_arg.path, generics, is_ref) {
2229                                                         if !self.write_c_mangled_container_path_intern(w, Self::path_to_generic_args(&$p_arg.path), generics,
2230                                                                         &subtype, is_ref, is_mut, ptr_for_ref, true) {
2231                                                                 return false;
2232                                                         }
2233                                                         self.write_c_mangled_container_path_intern(&mut mangled_type, Self::path_to_generic_args(&$p_arg.path),
2234                                                                 generics, &subtype, is_ref, is_mut, ptr_for_ref, true);
2235                                                         if let Some(w2) = $extra_write as Option<&mut Vec<u8>> {
2236                                                                 self.write_c_mangled_container_path_intern(w2, Self::path_to_generic_args(&$p_arg.path),
2237                                                                         generics, &subtype, is_ref, is_mut, ptr_for_ref, true);
2238                                                         }
2239                                                 } else {
2240                                                         let id = subtype.rsplitn(2, ':').next().unwrap(); // Get the "Base" name of the resolved type
2241                                                         write!(w, "{}", id).unwrap();
2242                                                         write!(mangled_type, "{}", id).unwrap();
2243                                                         if let Some(w2) = $extra_write as Option<&mut Vec<u8>> {
2244                                                                 write!(w2, "{}", id).unwrap();
2245                                                         }
2246                                                 }
2247                                         } else { return false; }
2248                                 }
2249                         }
2250                         if let syn::Type::Tuple(tuple) = arg {
2251                                 if tuple.elems.len() == 0 {
2252                                         write!(w, "None").unwrap();
2253                                         write!(mangled_type, "None").unwrap();
2254                                 } else {
2255                                         let mut mangled_tuple_type: Vec<u8> = Vec::new();
2256
2257                                         // Figure out what the mangled type should look like. To disambiguate
2258                                         // ((A, B), C) and (A, B, C) we prefix the generic args with a _ and suffix
2259                                         // them with a Z. Ideally we wouldn't use Z, but not many special chars are
2260                                         // available for use in type names.
2261                                         write!(w, "C{}Tuple_", tuple.elems.len()).unwrap();
2262                                         write!(mangled_type, "C{}Tuple_", tuple.elems.len()).unwrap();
2263                                         write!(mangled_tuple_type, "C{}Tuple_", tuple.elems.len()).unwrap();
2264                                         for elem in tuple.elems.iter() {
2265                                                 if let syn::Type::Path(p) = elem {
2266                                                         write_path!(p, Some(&mut mangled_tuple_type));
2267                                                 } else if let syn::Type::Reference(refelem) = elem {
2268                                                         if let syn::Type::Path(p) = &*refelem.elem {
2269                                                                 write_path!(p, Some(&mut mangled_tuple_type));
2270                                                         } else { return false; }
2271                                                 } else { return false; }
2272                                         }
2273                                         write!(w, "Z").unwrap();
2274                                         write!(mangled_type, "Z").unwrap();
2275                                         write!(mangled_tuple_type, "Z").unwrap();
2276                                         if !self.check_create_container(String::from_utf8(mangled_tuple_type).unwrap(),
2277                                                         &format!("{}Tuple", tuple.elems.len()), tuple.elems.iter().collect(), generics, is_ref) {
2278                                                 return false;
2279                                         }
2280                                 }
2281                         } else if let syn::Type::Path(p_arg) = arg {
2282                                 write_path!(p_arg, None);
2283                         } else if let syn::Type::Reference(refty) = arg {
2284                                 if let syn::Type::Path(p_arg) = &*refty.elem {
2285                                         write_path!(p_arg, None);
2286                                 } else if let syn::Type::Slice(_) = &*refty.elem {
2287                                         // write_c_type will actually do exactly what we want here, we just need to
2288                                         // make it a pointer so that its an option. Note that we cannot always convert
2289                                         // the Vec-as-slice (ie non-ref types) containers, so sometimes need to be able
2290                                         // to edit it, hence we use *mut here instead of *const.
2291                                         if args.len() != 1 { return false; }
2292                                         write!(w, "*mut ").unwrap();
2293                                         self.write_c_type(w, arg, None, true);
2294                                 } else { return false; }
2295                         } else if let syn::Type::Array(a) = arg {
2296                                 if let syn::Type::Path(p_arg) = &*a.elem {
2297                                         let resolved = self.resolve_path(&p_arg.path, generics);
2298                                         if !self.is_primitive(&resolved) { return false; }
2299                                         if let syn::Expr::Lit(syn::ExprLit { lit: syn::Lit::Int(len), .. }) = &a.len {
2300                                                 if self.c_type_from_path(&format!("[{}; {}]", resolved, len.base10_digits()), is_ref, ptr_for_ref).is_none() { return false; }
2301                                                 write!(w, "_{}{}", resolved, len.base10_digits()).unwrap();
2302                                                 write!(mangled_type, "_{}{}", resolved, len.base10_digits()).unwrap();
2303                                         } else { return false; }
2304                                 } else { return false; }
2305                         } else { return false; }
2306                 }
2307                 if self.is_transparent_container(ident, is_ref, args.iter().map(|a| *a)) { return true; }
2308                 // Push the "end of type" Z
2309                 write!(w, "Z").unwrap();
2310                 write!(mangled_type, "Z").unwrap();
2311
2312                 // Make sure the type is actually defined:
2313                 self.check_create_container(String::from_utf8(mangled_type).unwrap(), ident, args, generics, is_ref)
2314         }
2315         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 {
2316                 if !self.is_transparent_container(ident, is_ref, args.iter().map(|a| *a)) {
2317                         write!(w, "{}::", Self::generated_container_path()).unwrap();
2318                 }
2319                 self.write_c_mangled_container_path_intern(w, args, generics, ident, is_ref, is_mut, ptr_for_ref, false)
2320         }
2321
2322         // **********************************
2323         // *** C Type Equivalent Printing ***
2324         // **********************************
2325
2326         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 {
2327                 let full_path = match self.maybe_resolve_path(&path, generics) {
2328                         Some(path) => path, None => return false };
2329                 if let Some(c_type) = self.c_type_from_path(&full_path, is_ref, ptr_for_ref) {
2330                         write!(w, "{}", c_type).unwrap();
2331                         true
2332                 } else if self.crate_types.traits.get(&full_path).is_some() {
2333                         if is_ref && ptr_for_ref {
2334                                 write!(w, "*{} crate::{}", if is_mut { "mut" } else { "const" }, full_path).unwrap();
2335                         } else if is_ref {
2336                                 write!(w, "&{}crate::{}", if is_mut { "mut " } else { "" }, full_path).unwrap();
2337                         } else {
2338                                 write!(w, "crate::{}", full_path).unwrap();
2339                         }
2340                         true
2341                 } else if self.crate_types.opaques.get(&full_path).is_some() || self.crate_types.mirrored_enums.get(&full_path).is_some() {
2342                         if is_ref && ptr_for_ref {
2343                                 // ptr_for_ref implies we're returning the object, which we can't really do for
2344                                 // opaque or mirrored types without box'ing them, which is quite a waste, so return
2345                                 // the actual object itself (for opaque types we'll set the pointer to the actual
2346                                 // type and note that its a reference).
2347                                 write!(w, "crate::{}", full_path).unwrap();
2348                         } else if is_ref {
2349                                 write!(w, "&{}crate::{}", if is_mut { "mut " } else { "" }, full_path).unwrap();
2350                         } else {
2351                                 write!(w, "crate::{}", full_path).unwrap();
2352                         }
2353                         true
2354                 } else {
2355                         false
2356                 }
2357         }
2358         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 {
2359                 match t {
2360                         syn::Type::Path(p) => {
2361                                 if p.qself.is_some() {
2362                                         return false;
2363                                 }
2364                                 if let Some(full_path) = self.maybe_resolve_path(&p.path, generics) {
2365                                         if self.is_known_container(&full_path, is_ref) || self.is_path_transparent_container(&p.path, generics, is_ref) {
2366                                                 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);
2367                                         }
2368                                         if let Some(aliased_type) = self.crate_types.type_aliases.get(&full_path).cloned() {
2369                                                 return self.write_c_type_intern(w, &aliased_type, None, is_ref, is_mut, ptr_for_ref);
2370                                         }
2371                                 }
2372                                 self.write_c_path_intern(w, &p.path, generics, is_ref, is_mut, ptr_for_ref)
2373                         },
2374                         syn::Type::Reference(r) => {
2375                                 self.write_c_type_intern(w, &*r.elem, generics, true, r.mutability.is_some(), ptr_for_ref)
2376                         },
2377                         syn::Type::Array(a) => {
2378                                 if is_ref && is_mut {
2379                                         write!(w, "*mut [").unwrap();
2380                                         if !self.write_c_type_intern(w, &a.elem, generics, false, false, ptr_for_ref) { return false; }
2381                                 } else if is_ref {
2382                                         write!(w, "*const [").unwrap();
2383                                         if !self.write_c_type_intern(w, &a.elem, generics, false, false, ptr_for_ref) { return false; }
2384                                 } else {
2385                                         let mut typecheck = Vec::new();
2386                                         if !self.write_c_type_intern(&mut typecheck, &a.elem, generics, false, false, ptr_for_ref) { return false; }
2387                                         if typecheck[..] != ['u' as u8, '8' as u8] { return false; }
2388                                 }
2389                                 if let syn::Expr::Lit(l) = &a.len {
2390                                         if let syn::Lit::Int(i) = &l.lit {
2391                                                 if !is_ref {
2392                                                         if let Some(ty) = self.c_type_from_path(&format!("[u8; {}]", i.base10_digits()), false, ptr_for_ref) {
2393                                                                 write!(w, "{}", ty).unwrap();
2394                                                                 true
2395                                                         } else { false }
2396                                                 } else {
2397                                                         write!(w, "; {}]", i).unwrap();
2398                                                         true
2399                                                 }
2400                                         } else { false }
2401                                 } else { false }
2402                         }
2403                         syn::Type::Slice(s) => {
2404                                 if !is_ref || is_mut { return false; }
2405                                 if let syn::Type::Path(p) = &*s.elem {
2406                                         let resolved = self.resolve_path(&p.path, generics);
2407                                         if self.is_primitive(&resolved) {
2408                                                 write!(w, "{}::{}slice", Self::container_templ_path(), resolved).unwrap();
2409                                                 true
2410                                         } else { false }
2411                                 } else if let syn::Type::Reference(r) = &*s.elem {
2412                                         if let syn::Type::Path(p) = &*r.elem {
2413                                                 // Slices with "real types" inside are mapped as the equivalent non-ref Vec
2414                                                 let resolved = self.resolve_path(&p.path, generics);
2415                                                 let mangled_container = if let Some(ident) = self.crate_types.opaques.get(&resolved) {
2416                                                         format!("CVec_{}Z", ident)
2417                                                 } else if let Some(en) = self.crate_types.mirrored_enums.get(&resolved) {
2418                                                         format!("CVec_{}Z", en.ident)
2419                                                 } else if let Some(id) = p.path.get_ident() {
2420                                                         format!("CVec_{}Z", id)
2421                                                 } else { return false; };
2422                                                 write!(w, "{}::{}", Self::generated_container_path(), mangled_container).unwrap();
2423                                                 self.check_create_container(mangled_container, "Vec", vec![&*r.elem], generics, false)
2424                                         } else { false }
2425                                 } else if let syn::Type::Tuple(_) = &*s.elem {
2426                                         let mut args = syn::punctuated::Punctuated::<_, syn::token::Comma>::new();
2427                                         args.push(syn::GenericArgument::Type((*s.elem).clone()));
2428                                         let mut segments = syn::punctuated::Punctuated::new();
2429                                         segments.push(parse_quote!(Vec<#args>));
2430                                         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)
2431                                 } else { false }
2432                         },
2433                         syn::Type::Tuple(t) => {
2434                                 if t.elems.len() == 0 {
2435                                         true
2436                                 } else {
2437                                         self.write_c_mangled_container_path(w, t.elems.iter().collect(), generics,
2438                                                 &format!("{}Tuple", t.elems.len()), is_ref, is_mut, ptr_for_ref)
2439                                 }
2440                         },
2441                         _ => false,
2442                 }
2443         }
2444         pub fn write_c_type<W: std::io::Write>(&self, w: &mut W, t: &syn::Type, generics: Option<&GenericTypes>, ptr_for_ref: bool) {
2445                 assert!(self.write_c_type_intern(w, t, generics, false, false, ptr_for_ref));
2446         }
2447         pub fn understood_c_path(&self, p: &syn::Path) -> bool {
2448                 if p.leading_colon.is_some() { return false; }
2449                 self.write_c_path_intern(&mut std::io::sink(), p, None, false, false, false)
2450         }
2451         pub fn understood_c_type(&self, t: &syn::Type, generics: Option<&GenericTypes>) -> bool {
2452                 self.write_c_type_intern(&mut std::io::sink(), t, generics, false, false, false)
2453         }
2454 }