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

   1 use std::collections::HashMap;
   2 use std::fs::File;
   3 use std::io::Write;
   4 use std::hash;
   5
   6 use proc_macro2::{TokenTree, Span};
   7
   8 // The following utils are used purely to build our known types maps - they break down all the
   9 // types we need to resolve to include the given object, and no more.
  10
  11 pub fn first_seg_self<'a>(t: &'a syn::Type) -> Option<impl Iterator<Item=&syn::PathSegment> + 'a> {
  12         match t {
  13                 syn::Type::Path(p) => {
  14                         if p.qself.is_some() || p.path.leading_colon.is_some() {
  15                                 return None;
  16                         }
  17                         let mut segs = p.path.segments.iter();
  18                         let ty = segs.next().unwrap();
  19                         if !ty.arguments.is_empty() { return None; }
  20                         if format!("{}", ty.ident) == "Self" {
  21                                 Some(segs)
  22                         } else { None }
  23                 },
  24                 _ => None,
  25         }
  26 }
  27
  28 pub fn get_single_remaining_path_seg<'a, I: Iterator<Item=&'a syn::PathSegment>>(segs: &mut I) -> Option<&'a syn::Ident> {
  29         if let Some(ty) = segs.next() {
  30                 if !ty.arguments.is_empty() { unimplemented!(); }
  31                 if segs.next().is_some() { return None; }
  32                 Some(&ty.ident)
  33         } else { None }
  34 }
  35
  36 pub fn single_ident_generic_path_to_ident(p: &syn::Path) -> Option<&syn::Ident> {
  37         if p.segments.len() == 1 {
  38                 Some(&p.segments.iter().next().unwrap().ident)
  39         } else { None }
  40 }
  41
  42 #[derive(Debug, PartialEq)]
  43 pub enum ExportStatus {
  44         Export,
  45         NoExport,
  46         TestOnly,
  47 }
  48 /// Gets the ExportStatus of an object (struct, fn, etc) given its attributes.
  49 pub fn export_status(attrs: &[syn::Attribute]) -> ExportStatus {
  50         for attr in attrs.iter() {
  51                 let tokens_clone = attr.tokens.clone();
  52                 let mut token_iter = tokens_clone.into_iter();
  53                 if let Some(token) = token_iter.next() {
  54                         match token {
  55                                 TokenTree::Punct(c) if c.as_char() == '=' => {
  56                                         // Really not sure where syn gets '=' from here -
  57                                         // it somehow represents '///' or '//!'
  58                                 },
  59                                 TokenTree::Group(g) => {
  60                                         if format!("{}", single_ident_generic_path_to_ident(&attr.path).unwrap()) == "cfg" {
  61                                                 let mut iter = g.stream().into_iter();
  62                                                 if let TokenTree::Ident(i) = iter.next().unwrap() {
  63                                                         if i == "any" {
  64                                                                 // #[cfg(any(test, feature = ""))]
  65                                                                 if let TokenTree::Group(g) = iter.next().unwrap() {
  66                                                                         if let TokenTree::Ident(i) = g.stream().into_iter().next().unwrap() {
  67                                                                                 if i == "test" || i == "feature" {
  68                                                                                         // If its cfg(feature(...)) we assume its test-only
  69                                                                                         return ExportStatus::TestOnly;
  70                                                                                 }
  71                                                                         }
  72                                                                 }
  73                                                         } else if i == "test" || i == "feature" {
  74                                                                 // If its cfg(feature(...)) we assume its test-only
  75                                                                 return ExportStatus::TestOnly;
  76                                                         }
  77                                                 }
  78                                         }
  79                                         continue; // eg #[derive()]
  80                                 },
  81                                 _ => unimplemented!(),
  82                         }
  83                 } else { continue; }
  84                 match token_iter.next().unwrap() {
  85                         TokenTree::Literal(lit) => {
  86                                 let line = format!("{}", lit);
  87                                 if line.contains("(C-not exported)") {
  88                                         return ExportStatus::NoExport;
  89                                 }
  90                         },
  91                         _ => unimplemented!(),
  92                 }
  93         }
  94         ExportStatus::Export
  95 }
  96
  97 pub fn assert_simple_bound(bound: &syn::TraitBound) {
  98         if bound.paren_token.is_some() || bound.lifetimes.is_some() { unimplemented!(); }
  99         if let syn::TraitBoundModifier::Maybe(_) = bound.modifier { unimplemented!(); }
 100 }
 101
 102 /// A stack of sets of generic resolutions.
 103 ///
 104 /// This tracks the template parameters for a function, struct, or trait, allowing resolution into
 105 /// a concrete type. By pushing a new context onto the stack, this can track a function's template
 106 /// parameters inside of a generic struct or trait.
 107 ///
 108 /// It maps both direct types as well as Deref<Target = X>, mapping them via the provided
 109 /// TypeResolver's resolve_path function (ie traits map to the concrete jump table, structs to the
 110 /// concrete C container struct, etc).
 111 pub struct GenericTypes<'a> {
 112         typed_generics: Vec<HashMap<&'a syn::Ident, (String, Option<&'a syn::Path>)>>,
 113 }
 114 impl<'a> GenericTypes<'a> {
 115         pub fn new() -> Self {
 116                 Self { typed_generics: vec![HashMap::new()], }
 117         }
 118
 119         /// push a new context onto the stack, allowing for a new set of generics to be learned which
 120         /// will override any lower contexts, but which will still fall back to resoltion via lower
 121         /// contexts.
 122         pub fn push_ctx(&mut self) {
 123                 self.typed_generics.push(HashMap::new());
 124         }
 125         /// pop the latest context off the stack.
 126         pub fn pop_ctx(&mut self) {
 127                 self.typed_generics.pop();
 128         }
 129
 130         /// Learn the generics in generics in the current context, given a TypeResolver.
 131         pub fn learn_generics<'b, 'c>(&mut self, generics: &'a syn::Generics, types: &'b TypeResolver<'a, 'c>) -> bool {
 132                 // First learn simple generics...
 133                 for generic in generics.params.iter() {
 134                         match generic {
 135                                 syn::GenericParam::Type(type_param) => {
 136                                         let mut non_lifetimes_processed = false;
 137                                         for bound in type_param.bounds.iter() {
 138                                                 if let syn::TypeParamBound::Trait(trait_bound) = bound {
 139                                                         if let Some(ident) = single_ident_generic_path_to_ident(&trait_bound.path) {
 140                                                                 match &format!("{}", ident) as &str { "Send" => continue, "Sync" => continue, _ => {} }
 141                                                         }
 142
 143                                                         assert_simple_bound(&trait_bound);
 144                                                         if let Some(mut path) = types.maybe_resolve_path(&trait_bound.path, None) {
 145                                                                 if types.skip_path(&path) { continue; }
 146                                                                 if non_lifetimes_processed { return false; }
 147                                                                 non_lifetimes_processed = true;
 148                                                                 let new_ident = if path != "std::ops::Deref" {
 149                                                                         path = "crate::".to_string() + &path;
 150                                                                         Some(&trait_bound.path)
 151                                                                 } else { None };
 152                                                                 self.typed_generics.last_mut().unwrap().insert(&type_param.ident, (path, new_ident));
 153                                                         } else { return false; }
 154                                                 }
 155                                         }
 156                                 },
 157                                 _ => {},
 158                         }
 159                 }
 160                 // Then find generics where we are required to pass a Deref<Target=X> and pretend its just X.
 161                 if let Some(wh) = &generics.where_clause {
 162                         for pred in wh.predicates.iter() {
 163                                 if let syn::WherePredicate::Type(t) = pred {
 164                                         if let syn::Type::Path(p) = &t.bounded_ty {
 165                                                 if p.qself.is_some() { return false; }
 166                                                 if p.path.leading_colon.is_some() { return false; }
 167                                                 let mut p_iter = p.path.segments.iter();
 168                                                 if let Some(gen) = self.typed_generics.last_mut().unwrap().get_mut(&p_iter.next().unwrap().ident) {
 169                                                         if gen.0 != "std::ops::Deref" { return false; }
 170                                                         if &format!("{}", p_iter.next().unwrap().ident) != "Target" { return false; }
 171
 172                                                         let mut non_lifetimes_processed = false;
 173                                                         for bound in t.bounds.iter() {
 174                                                                 if let syn::TypeParamBound::Trait(trait_bound) = bound {
 175                                                                         if non_lifetimes_processed { return false; }
 176                                                                         non_lifetimes_processed = true;
 177                                                                         assert_simple_bound(&trait_bound);
 178                                                                         *gen = ("crate::".to_string() + &types.resolve_path(&trait_bound.path, None),
 179                                                                                 Some(&trait_bound.path));
 180                                                                 }
 181                                                         }
 182                                                 } else { return false; }
 183                                         } else { return false; }
 184                                 }
 185                         }
 186                 }
 187                 for (_, (_, ident)) in self.typed_generics.last().unwrap().iter() {
 188                         if ident.is_none() { return false; }
 189                 }
 190                 true
 191         }
 192
 193         /// Learn the associated types from the trait in the current context.
 194         pub fn learn_associated_types<'b, 'c>(&mut self, t: &'a syn::ItemTrait, types: &'b TypeResolver<'a, 'c>) {
 195                 for item in t.items.iter() {
 196                         match item {
 197                                 &syn::TraitItem::Type(ref t) => {
 198                                         if t.default.is_some() || t.generics.lt_token.is_some() { unimplemented!(); }
 199                                         let mut bounds_iter = t.bounds.iter();
 200                                         match bounds_iter.next().unwrap() {
 201                                                 syn::TypeParamBound::Trait(tr) => {
 202                                                         assert_simple_bound(&tr);
 203                                                         if let Some(mut path) = types.maybe_resolve_path(&tr.path, None) {
 204                                                                 if types.skip_path(&path) { continue; }
 205                                                                 // In general we handle Deref<Target=X> as if it were just X (and
 206                                                                 // implement Deref<Target=Self> for relevant types). We don't
 207                                                                 // bother to implement it for associated types, however, so we just
 208                                                                 // ignore such bounds.
 209                                                                 let new_ident = if path != "std::ops::Deref" {
 210                                                                         path = "crate::".to_string() + &path;
 211                                                                         Some(&tr.path)
 212                                                                 } else { None };
 213                                                                 self.typed_generics.last_mut().unwrap().insert(&t.ident, (path, new_ident));
 214                                                         } else { unimplemented!(); }
 215                                                 },
 216                                                 _ => unimplemented!(),
 217                                         }
 218                                         if bounds_iter.next().is_some() { unimplemented!(); }
 219                                 },
 220                                 _ => {},
 221                         }
 222                 }
 223         }
 224
 225         /// Attempt to resolve an Ident as a generic parameter and return the full path.
 226         pub fn maybe_resolve_ident<'b>(&'b self, ident: &syn::Ident) -> Option<&'b String> {
 227                 for gen in self.typed_generics.iter().rev() {
 228                         if let Some(res) = gen.get(ident).map(|(a, _)| a) {
 229                                 return Some(res);
 230                         }
 231                 }
 232                 None
 233         }
 234         /// Attempt to resolve a Path as a generic parameter and return the full path. as both a string
 235         /// and syn::Path.
 236         pub fn maybe_resolve_path<'b>(&'b self, path: &syn::Path) -> Option<(&'b String, &'a syn::Path)> {
 237                 if let Some(ident) = path.get_ident() {
 238                         for gen in self.typed_generics.iter().rev() {
 239                                 if let Some(res) = gen.get(ident).map(|(a, b)| (a, b.unwrap())) {
 240                                         return Some(res);
 241                                 }
 242                         }
 243                 } else {
 244                         // Associated types are usually specified as "Self::Generic", so we check for that
 245                         // explicitly here.
 246                         let mut it = path.segments.iter();
 247                         if path.segments.len() == 2 && format!("{}", it.next().unwrap().ident) == "Self" {
 248                                 let ident = &it.next().unwrap().ident;
 249                                 for gen in self.typed_generics.iter().rev() {
 250                                         if let Some(res) = gen.get(ident).map(|(a, b)| (a, b.unwrap())) {
 251                                                 return Some(res);
 252                                         }
 253                                 }
 254                         }
 255                 }
 256                 None
 257         }
 258 }
 259
 260 #[derive(Clone, PartialEq)]
 261 // The type of declaration and the object itself
 262 pub enum DeclType<'a> {
 263         MirroredEnum,
 264         Trait(&'a syn::ItemTrait),
 265         StructImported,
 266         StructIgnored,
 267         EnumIgnored,
 268 }
 269
 270 // templates_defined is walked to write the C++ header, so if we use the default hashing it get
 271 // reordered on each genbindings run. Instead, we use SipHasher (which defaults to 0-keys) so that
 272 // the sorting is stable across runs. It is deprecated, but the "replacement" doesn't actually
 273 // accomplish the same goals, so we just ignore it.
 274 #[allow(deprecated)]
 275 type NonRandomHash = hash::BuildHasherDefault<hash::SipHasher>;
 276
 277 /// Top-level struct tracking everything which has been defined while walking the crate.
 278 pub struct CrateTypes<'a> {
 279         /// This may contain structs or enums, but only when either is mapped as
 280         /// struct X { inner: *mut originalX, .. }
 281         pub opaques: HashMap<String, &'a syn::Ident>,
 282         /// Enums which are mapped as C enums with conversion functions
 283         pub mirrored_enums: HashMap<String, &'a syn::ItemEnum>,
 284         /// Traits which are mapped as a pointer + jump table
 285         pub traits: HashMap<String, &'a syn::ItemTrait>,
 286         /// Aliases from paths to some other Type
 287         pub type_aliases: HashMap<String, syn::Type>,
 288         /// Template continer types defined, map from mangled type name -> whether a destructor fn
 289         /// exists.
 290         ///
 291         /// This is used at the end of processing to make C++ wrapper classes
 292         pub templates_defined: HashMap<String, bool, NonRandomHash>,
 293         /// The output file for any created template container types, written to as we find new
 294         /// template containers which need to be defined.
 295         pub template_file: &'a mut File,
 296 }
 297
 298 /// A struct which tracks resolving rust types into C-mapped equivalents, exists for one specific
 299 /// module but contains a reference to the overall CrateTypes tracking.
 300 pub struct TypeResolver<'mod_lifetime, 'crate_lft: 'mod_lifetime> {
 301         pub orig_crate: &'mod_lifetime str,
 302         pub module_path: &'mod_lifetime str,
 303         imports: HashMap<syn::Ident, String>,
 304         // ident -> is-mirrored-enum
 305         declared: HashMap<syn::Ident, DeclType<'crate_lft>>,
 306         pub crate_types: &'mod_lifetime mut CrateTypes<'crate_lft>,
 307 }
 308
 309 /// Returned by write_empty_rust_val_check_suffix to indicate what type of dereferencing needs to
 310 /// happen to get the inner value of a generic.
 311 enum EmptyValExpectedTy {
 312         /// A type which has a flag for being empty (eg an array where we treat all-0s as empty).
 313         NonPointer,
 314         /// A pointer that we want to dereference and move out of.
 315         OwnedPointer,
 316         /// A pointer which we want to convert to a reference.
 317         ReferenceAsPointer,
 318 }
 319
 320 impl<'a, 'c: 'a> TypeResolver<'a, 'c> {
 321         pub fn new(orig_crate: &'a str, module_path: &'a str, crate_types: &'a mut CrateTypes<'c>) -> Self {
 322                 let mut imports = HashMap::new();
 323                 // Add primitives to the "imports" list:
 324                 imports.insert(syn::Ident::new("bool", Span::call_site()), "bool".to_string());
 325                 imports.insert(syn::Ident::new("u64", Span::call_site()), "u64".to_string());
 326                 imports.insert(syn::Ident::new("u32", Span::call_site()), "u32".to_string());
 327                 imports.insert(syn::Ident::new("u16", Span::call_site()), "u16".to_string());
 328                 imports.insert(syn::Ident::new("u8", Span::call_site()), "u8".to_string());
 329                 imports.insert(syn::Ident::new("usize", Span::call_site()), "usize".to_string());
 330                 imports.insert(syn::Ident::new("str", Span::call_site()), "str".to_string());
 331                 imports.insert(syn::Ident::new("String", Span::call_site()), "String".to_string());
 332
 333                 // These are here to allow us to print native Rust types in trait fn impls even if we don't
 334                 // have C mappings:
 335                 imports.insert(syn::Ident::new("Result", Span::call_site()), "Result".to_string());
 336                 imports.insert(syn::Ident::new("Vec", Span::call_site()), "Vec".to_string());
 337                 imports.insert(syn::Ident::new("Option", Span::call_site()), "Option".to_string());
 338                 Self { orig_crate, module_path, imports, declared: HashMap::new(), crate_types }
 339         }
 340
 341         // *************************************************
 342         // *** Well know type and conversion definitions ***
 343         // *************************************************
 344
 345         /// Returns true we if can just skip passing this to C entirely
 346         fn skip_path(&self, full_path: &str) -> bool {
 347                 full_path == "bitcoin::secp256k1::Secp256k1" ||
 348                 full_path == "bitcoin::secp256k1::Signing" ||
 349                 full_path == "bitcoin::secp256k1::Verification"
 350         }
 351         /// Returns true we if can just skip passing this to C entirely
 352         fn no_arg_path_to_rust(&self, full_path: &str) -> &str {
 353                 if full_path == "bitcoin::secp256k1::Secp256k1" {
 354                         "&bitcoin::secp256k1::Secp256k1::new()"
 355                 } else { unimplemented!(); }
 356         }
 357
 358         /// Returns true if the object is a primitive and is mapped as-is with no conversion
 359         /// whatsoever.
 360         pub fn is_primitive(&self, full_path: &str) -> bool {
 361                 match full_path {
 362                         "bool" => true,
 363                         "u64" => true,
 364                         "u32" => true,
 365                         "u16" => true,
 366                         "u8" => true,
 367                         "usize" => true,
 368                         _ => false,
 369                 }
 370         }
 371         /// Gets the C-mapped type for types which are outside of the crate, or which are manually
 372         /// ignored by for some reason need mapping anyway.
 373         fn c_type_from_path<'b>(&self, full_path: &'b str, is_ref: bool, ptr_for_ref: bool) -> Option<&'b str> {
 374                 if self.is_primitive(full_path) {
 375                         return Some(full_path);
 376                 }
 377                 match full_path {
 378                         "Result" => Some("crate::c_types::derived::CResult"),
 379                         "Vec" if !is_ref => Some("crate::c_types::derived::CVec"),
 380                         "Option" => Some(""),
 381
 382                         // Note that no !is_ref types can map to an array because Rust and C's call semantics
 383                         // for arrays are different (https://github.com/eqrion/cbindgen/issues/528)
 384
 385                         "[u8; 32]" if !is_ref => Some("crate::c_types::ThirtyTwoBytes"),
 386                         "[u8; 16]" if !is_ref => Some("crate::c_types::SixteenBytes"),
 387                         "[u8; 10]" if !is_ref => Some("crate::c_types::TenBytes"),
 388                         "[u8; 4]" if !is_ref => Some("crate::c_types::FourBytes"),
 389                         "[u8; 3]" if !is_ref => Some("crate::c_types::ThreeBytes"), // Used for RGB values
 390
 391                         "str" if is_ref => Some("crate::c_types::Str"),
 392                         "String" if !is_ref => Some("crate::c_types::derived::CVec_u8Z"),
 393                         "String" if is_ref => Some("crate::c_types::Str"),
 394
 395                         "std::time::Duration" => Some("u64"),
 396
 397                         "bitcoin::secp256k1::key::PublicKey" => Some("crate::c_types::PublicKey"),
 398                         "bitcoin::secp256k1::Signature" => Some("crate::c_types::Signature"),
 399                         "bitcoin::secp256k1::key::SecretKey" if is_ref  => Some("*const [u8; 32]"),
 400                         "bitcoin::secp256k1::key::SecretKey" if !is_ref => Some("crate::c_types::SecretKey"),
 401                         "bitcoin::secp256k1::Error" if !is_ref => Some("crate::c_types::Secp256k1Error"),
 402                         "bitcoin::blockdata::script::Script" if is_ref => Some("crate::c_types::u8slice"),
 403                         "bitcoin::blockdata::script::Script" if !is_ref => Some("crate::c_types::derived::CVec_u8Z"),
 404                         "bitcoin::blockdata::transaction::OutPoint" => Some("crate::chain::transaction::OutPoint"),
 405                         "bitcoin::blockdata::transaction::Transaction" => Some("crate::c_types::Transaction"),
 406                         "bitcoin::blockdata::transaction::TxOut" if !is_ref => Some("crate::c_types::TxOut"),
 407                         "bitcoin::network::constants::Network" => Some("crate::bitcoin::network::Network"),
 408                         "bitcoin::blockdata::block::BlockHeader" if is_ref  => Some("*const [u8; 80]"),
 409                         "bitcoin::blockdata::block::Block" if is_ref  => Some("crate::c_types::u8slice"),
 410
 411                         // Newtypes that we just expose in their original form.
 412                         "bitcoin::hash_types::Txid" if is_ref  => Some("*const [u8; 32]"),
 413                         "bitcoin::hash_types::Txid" if !is_ref => Some("crate::c_types::ThirtyTwoBytes"),
 414                         "bitcoin::hash_types::BlockHash" if is_ref  => Some("*const [u8; 32]"),
 415                         "bitcoin::hash_types::BlockHash" if !is_ref => Some("crate::c_types::ThirtyTwoBytes"),
 416                         "bitcoin::secp256k1::Message" if !is_ref => Some("crate::c_types::ThirtyTwoBytes"),
 417                         "ln::channelmanager::PaymentHash" if is_ref => Some("*const [u8; 32]"),
 418                         "ln::channelmanager::PaymentHash" if !is_ref => Some("crate::c_types::ThirtyTwoBytes"),
 419                         "ln::channelmanager::PaymentPreimage" if is_ref => Some("*const [u8; 32]"),
 420                         "ln::channelmanager::PaymentPreimage" if !is_ref => Some("crate::c_types::ThirtyTwoBytes"),
 421                         "ln::channelmanager::PaymentSecret" if is_ref => Some("crate::c_types::ThirtyTwoBytes"),
 422                         "ln::channelmanager::PaymentSecret" if !is_ref => Some("crate::c_types::ThirtyTwoBytes"),
 423
 424                         // Override the default since Records contain an fmt with a lifetime:
 425                         "util::logger::Record" => Some("*const std::os::raw::c_char"),
 426
 427                         // List of structs we map that aren't detected:
 428                         "ln::features::InitFeatures" if is_ref && ptr_for_ref => Some("crate::ln::features::InitFeatures"),
 429                         "ln::features::InitFeatures" if is_ref => Some("*const crate::ln::features::InitFeatures"),
 430                         "ln::features::InitFeatures" => Some("crate::ln::features::InitFeatures"),
 431                         _ => {
 432                                 eprintln!("    Type {} (ref: {}) unresolvable in C", full_path, is_ref);
 433                                 None
 434                         },
 435                 }
 436         }
 437
 438         fn from_c_conversion_new_var_from_path<'b>(&self, _full_path: &str, _is_ref: bool) -> Option<(&'b str, &'b str)> {
 439                 None
 440         }
 441         fn from_c_conversion_prefix_from_path<'b>(&self, full_path: &str, is_ref: bool) -> Option<String> {
 442                 if self.is_primitive(full_path) {
 443                         return Some("".to_owned());
 444                 }
 445                 match full_path {
 446                         "Vec" if !is_ref => Some("local_"),
 447                         "Result" if !is_ref => Some("local_"),
 448                         "Option" if is_ref => Some("&local_"),
 449                         "Option" => Some("local_"),
 450
 451                         "[u8; 32]" if is_ref => Some("unsafe { &*"),
 452                         "[u8; 32]" if !is_ref => Some(""),
 453                         "[u8; 16]" if !is_ref => Some(""),
 454                         "[u8; 10]" if !is_ref => Some(""),
 455                         "[u8; 4]" if !is_ref => Some(""),
 456                         "[u8; 3]" if !is_ref => Some(""),
 457
 458                         "[u8]" if is_ref => Some(""),
 459                         "[usize]" if is_ref => Some(""),
 460
 461                         "str" if is_ref => Some(""),
 462                         "String" if !is_ref => Some("String::from_utf8("),
 463                         // Note that we'll panic for String if is_ref, as we only have non-owned memory, we
 464                         // cannot create a &String.
 465
 466                         "std::time::Duration" => Some("std::time::Duration::from_secs("),
 467
 468                         "bitcoin::secp256k1::key::PublicKey" if is_ref => Some("&"),
 469                         "bitcoin::secp256k1::key::PublicKey" => Some(""),
 470                         "bitcoin::secp256k1::Signature" if is_ref => Some("&"),
 471                         "bitcoin::secp256k1::Signature" => Some(""),
 472                         "bitcoin::secp256k1::key::SecretKey" if is_ref => Some("&::bitcoin::secp256k1::key::SecretKey::from_slice(&unsafe { *"),
 473                         "bitcoin::secp256k1::key::SecretKey" if !is_ref => Some(""),
 474                         "bitcoin::blockdata::script::Script" if is_ref => Some("&::bitcoin::blockdata::script::Script::from(Vec::from("),
 475                         "bitcoin::blockdata::script::Script" if !is_ref => Some("::bitcoin::blockdata::script::Script::from("),
 476                         "bitcoin::blockdata::transaction::Transaction" if is_ref => Some("&"),
 477                         "bitcoin::blockdata::transaction::Transaction" => Some(""),
 478                         "bitcoin::blockdata::transaction::TxOut" if !is_ref => Some(""),
 479                         "bitcoin::network::constants::Network" => Some(""),
 480                         "bitcoin::blockdata::block::BlockHeader" => Some("&::bitcoin::consensus::encode::deserialize(unsafe { &*"),
 481                         "bitcoin::blockdata::block::Block" if is_ref => Some("&::bitcoin::consensus::encode::deserialize("),
 482
 483                         // Newtypes that we just expose in their original form.
 484                         "bitcoin::hash_types::Txid" if is_ref => Some("&::bitcoin::hash_types::Txid::from_slice(&unsafe { &*"),
 485                         "bitcoin::hash_types::Txid" if !is_ref => Some("::bitcoin::hash_types::Txid::from_slice(&"),
 486                         "bitcoin::hash_types::BlockHash" => Some("::bitcoin::hash_types::BlockHash::from_slice(&"),
 487                         "ln::channelmanager::PaymentHash" if !is_ref => Some("::lightning::ln::channelmanager::PaymentHash("),
 488                         "ln::channelmanager::PaymentHash" if is_ref => Some("&::lightning::ln::channelmanager::PaymentHash(unsafe { *"),
 489                         "ln::channelmanager::PaymentPreimage" if !is_ref => Some("::lightning::ln::channelmanager::PaymentPreimage("),
 490                         "ln::channelmanager::PaymentPreimage" if is_ref => Some("&::lightning::ln::channelmanager::PaymentPreimage(unsafe { *"),
 491                         "ln::channelmanager::PaymentSecret" => Some("::lightning::ln::channelmanager::PaymentSecret("),
 492
 493                         // List of structs we map (possibly during processing of other files):
 494                         "ln::features::InitFeatures" if !is_ref => Some("*unsafe { Box::from_raw("),
 495
 496                         // List of traits we map (possibly during processing of other files):
 497                         "crate::util::logger::Logger" => Some(""),
 498
 499                         _ => {
 500                                 eprintln!("    Type {} unconvertable from C", full_path);
 501                                 None
 502                         },
 503                 }.map(|s| s.to_owned())
 504         }
 505         fn from_c_conversion_suffix_from_path<'b>(&self, full_path: &str, is_ref: bool) -> Option<String> {
 506                 if self.is_primitive(full_path) {
 507                         return Some("".to_owned());
 508                 }
 509                 match full_path {
 510                         "Vec" if !is_ref => Some(""),
 511                         "Option" => Some(""),
 512                         "Result" if !is_ref => Some(""),
 513
 514                         "[u8; 32]" if is_ref => Some("}"),
 515                         "[u8; 32]" if !is_ref => Some(".data"),
 516                         "[u8; 16]" if !is_ref => Some(".data"),
 517                         "[u8; 10]" if !is_ref => Some(".data"),
 518                         "[u8; 4]" if !is_ref => Some(".data"),
 519                         "[u8; 3]" if !is_ref => Some(".data"),
 520
 521                         "[u8]" if is_ref => Some(".to_slice()"),
 522                         "[usize]" if is_ref => Some(".to_slice()"),
 523
 524                         "str" if is_ref => Some(".into()"),
 525                         "String" if !is_ref => Some(".into_rust()).unwrap()"),
 526
 527                         "std::time::Duration" => Some(")"),
 528
 529                         "bitcoin::secp256k1::key::PublicKey" => Some(".into_rust()"),
 530                         "bitcoin::secp256k1::Signature" => Some(".into_rust()"),
 531                         "bitcoin::secp256k1::key::SecretKey" if !is_ref => Some(".into_rust()"),
 532                         "bitcoin::secp256k1::key::SecretKey" if is_ref => Some("}[..]).unwrap()"),
 533                         "bitcoin::blockdata::script::Script" if is_ref => Some(".to_slice()))"),
 534                         "bitcoin::blockdata::script::Script" if !is_ref => Some(".into_rust())"),
 535                         "bitcoin::blockdata::transaction::Transaction" => Some(".into_bitcoin()"),
 536                         "bitcoin::blockdata::transaction::TxOut" if !is_ref => Some(".into_rust()"),
 537                         "bitcoin::network::constants::Network" => Some(".into_bitcoin()"),
 538                         "bitcoin::blockdata::block::BlockHeader" => Some(" }).unwrap()"),
 539                         "bitcoin::blockdata::block::Block" => Some(".to_slice()).unwrap()"),
 540
 541                         // Newtypes that we just expose in their original form.
 542                         "bitcoin::hash_types::Txid" if is_ref => Some(" }[..]).unwrap()"),
 543                         "bitcoin::hash_types::Txid" => Some(".data[..]).unwrap()"),
 544                         "bitcoin::hash_types::BlockHash" if !is_ref => Some(".data[..]).unwrap()"),
 545                         "ln::channelmanager::PaymentHash" if !is_ref => Some(".data)"),
 546                         "ln::channelmanager::PaymentHash" if is_ref => Some(" })"),
 547                         "ln::channelmanager::PaymentPreimage" if !is_ref => Some(".data)"),
 548                         "ln::channelmanager::PaymentPreimage" if is_ref => Some(" })"),
 549                         "ln::channelmanager::PaymentSecret" => Some(".data)"),
 550
 551                         // List of structs we map (possibly during processing of other files):
 552                         "ln::features::InitFeatures" if is_ref => Some(".inner) }"),
 553                         "ln::features::InitFeatures" if !is_ref => Some(".take_inner()) }"),
 554
 555                         // List of traits we map (possibly during processing of other files):
 556                         "crate::util::logger::Logger" => Some(""),
 557
 558                         _ => {
 559                                 eprintln!("    Type {} unconvertable from C", full_path);
 560                                 None
 561                         },
 562                 }.map(|s| s.to_owned())
 563         }
 564
 565         fn to_c_conversion_new_var_from_path<'b>(&self, full_path: &str, is_ref: bool) -> Option<(&'b str, &'b str)> {
 566                 if self.is_primitive(full_path) {
 567                         return None;
 568                 }
 569                 match full_path {
 570                         "[u8]" if is_ref => Some(("crate::c_types::u8slice::from_slice(", ")")),
 571                         "[usize]" if is_ref => Some(("crate::c_types::usizeslice::from_slice(", ")")),
 572
 573                         "bitcoin::blockdata::transaction::Transaction" if is_ref => Some(("::bitcoin::consensus::encode::serialize(", ")")),
 574                         "bitcoin::blockdata::transaction::Transaction" if !is_ref => Some(("::bitcoin::consensus::encode::serialize(&", ")")),
 575                         "bitcoin::blockdata::block::BlockHeader" if is_ref => Some(("{ let mut s = [0u8; 80]; s[..].copy_from_slice(&::bitcoin::consensus::encode::serialize(", ")); s }")),
 576                         "bitcoin::blockdata::block::Block" if is_ref => Some(("::bitcoin::consensus::encode::serialize(", ")")),
 577                         "bitcoin::hash_types::Txid" => None,
 578
 579                         // Override the default since Records contain an fmt with a lifetime:
 580                         // TODO: We should include the other record fields
 581                         "util::logger::Record" => Some(("std::ffi::CString::new(format!(\"{}\", ", ".args)).unwrap()")),
 582                         _ => None,
 583                 }.map(|s| s.to_owned())
 584         }
 585         fn to_c_conversion_inline_prefix_from_path(&self, full_path: &str, is_ref: bool, ptr_for_ref: bool) -> Option<String> {
 586                 if self.is_primitive(full_path) {
 587                         return Some("".to_owned());
 588                 }
 589                 match full_path {
 590                         "Result" if !is_ref => Some("local_"),
 591                         "Vec" if !is_ref => Some("local_"),
 592                         "Option" => Some("local_"),
 593
 594                         "[u8; 32]" if !is_ref => Some("crate::c_types::ThirtyTwoBytes { data: "),
 595                         "[u8; 32]" if is_ref => Some("&"),
 596                         "[u8; 16]" if !is_ref => Some("crate::c_types::SixteenBytes { data: "),
 597                         "[u8; 10]" if !is_ref => Some("crate::c_types::TenBytes { data: "),
 598                         "[u8; 4]" if !is_ref => Some("crate::c_types::FourBytes { data: "),
 599                         "[u8; 3]" if is_ref => Some("&"),
 600
 601                         "[u8]" if is_ref => Some("local_"),
 602                         "[usize]" if is_ref => Some("local_"),
 603
 604                         "str" if is_ref => Some(""),
 605                         "String" => Some(""),
 606
 607                         "std::time::Duration" => Some(""),
 608
 609                         "bitcoin::secp256k1::key::PublicKey" => Some("crate::c_types::PublicKey::from_rust(&"),
 610                         "bitcoin::secp256k1::Signature" => Some("crate::c_types::Signature::from_rust(&"),
 611                         "bitcoin::secp256k1::key::SecretKey" if is_ref  => Some(""),
 612                         "bitcoin::secp256k1::key::SecretKey" if !is_ref => Some("crate::c_types::SecretKey::from_rust("),
 613                         "bitcoin::secp256k1::Error" if !is_ref => Some("crate::c_types::Secp256k1Error::from_rust("),
 614                         "bitcoin::blockdata::script::Script" if is_ref => Some("crate::c_types::u8slice::from_slice(&"),
 615                         "bitcoin::blockdata::script::Script" if !is_ref => Some(""),
 616                         "bitcoin::blockdata::transaction::Transaction" => Some("crate::c_types::Transaction::from_vec(local_"),
 617                         "bitcoin::blockdata::transaction::OutPoint" => Some("crate::c_types::bitcoin_to_C_outpoint("),
 618                         "bitcoin::blockdata::transaction::TxOut" if !is_ref => Some("crate::c_types::TxOut::from_rust("),
 619                         "bitcoin::blockdata::block::BlockHeader" if is_ref => Some("&local_"),
 620                         "bitcoin::blockdata::block::Block" if is_ref => Some("crate::c_types::u8slice::from_slice(&local_"),
 621
 622                         "bitcoin::hash_types::Txid" if !is_ref => Some("crate::c_types::ThirtyTwoBytes { data: "),
 623
 624                         // Newtypes that we just expose in their original form.
 625                         "bitcoin::hash_types::Txid" if is_ref => Some(""),
 626                         "bitcoin::hash_types::BlockHash" if is_ref => Some(""),
 627                         "bitcoin::hash_types::BlockHash" => Some("crate::c_types::ThirtyTwoBytes { data: "),
 628                         "bitcoin::secp256k1::Message" if !is_ref => Some("crate::c_types::ThirtyTwoBytes { data: "),
 629                         "ln::channelmanager::PaymentHash" if is_ref => Some("&"),
 630                         "ln::channelmanager::PaymentHash" if !is_ref => Some("crate::c_types::ThirtyTwoBytes { data: "),
 631                         "ln::channelmanager::PaymentPreimage" if is_ref => Some("&"),
 632                         "ln::channelmanager::PaymentPreimage" => Some("crate::c_types::ThirtyTwoBytes { data: "),
 633                         "ln::channelmanager::PaymentSecret" if !is_ref => Some("crate::c_types::ThirtyTwoBytes { data: "),
 634
 635                         // Override the default since Records contain an fmt with a lifetime:
 636                         "util::logger::Record" => Some("local_"),
 637
 638                         // List of structs we map (possibly during processing of other files):
 639                         "ln::features::InitFeatures" if is_ref && ptr_for_ref => Some("crate::ln::features::InitFeatures { inner: &mut "),
 640                         "ln::features::InitFeatures" if is_ref => Some("Box::into_raw(Box::new(crate::ln::features::InitFeatures { inner: &mut "),
 641                         "ln::features::InitFeatures" if !is_ref => Some("crate::ln::features::InitFeatures { inner: Box::into_raw(Box::new("),
 642
 643                         _ => {
 644                                 eprintln!("    Type {} (is_ref: {}) unconvertable to C", full_path, is_ref);
 645                                 None
 646                         },
 647                 }.map(|s| s.to_owned())
 648         }
 649         fn to_c_conversion_inline_suffix_from_path(&self, full_path: &str, is_ref: bool, ptr_for_ref: bool) -> Option<String> {
 650                 if self.is_primitive(full_path) {
 651                         return Some("".to_owned());
 652                 }
 653                 match full_path {
 654                         "Result" if !is_ref => Some(""),
 655                         "Vec" if !is_ref => Some(".into()"),
 656                         "Option" => Some(""),
 657
 658                         "[u8; 32]" if !is_ref => Some(" }"),
 659                         "[u8; 32]" if is_ref => Some(""),
 660                         "[u8; 16]" if !is_ref => Some(" }"),
 661                         "[u8; 10]" if !is_ref => Some(" }"),
 662                         "[u8; 4]" if !is_ref => Some(" }"),
 663                         "[u8; 3]" if is_ref => Some(""),
 664
 665                         "[u8]" if is_ref => Some(""),
 666                         "[usize]" if is_ref => Some(""),
 667
 668                         "str" if is_ref => Some(".into()"),
 669                         "String" if !is_ref => Some(".into_bytes().into()"),
 670                         "String" if is_ref => Some(".as_str().into()"),
 671
 672                         "std::time::Duration" => Some(".as_secs()"),
 673
 674                         "bitcoin::secp256k1::key::PublicKey" => Some(")"),
 675                         "bitcoin::secp256k1::Signature" => Some(")"),
 676                         "bitcoin::secp256k1::key::SecretKey" if !is_ref => Some(")"),
 677                         "bitcoin::secp256k1::key::SecretKey" if is_ref => Some(".as_ref()"),
 678                         "bitcoin::secp256k1::Error" if !is_ref => Some(")"),
 679                         "bitcoin::blockdata::script::Script" if is_ref => Some("[..])"),
 680                         "bitcoin::blockdata::script::Script" if !is_ref => Some(".into_bytes().into()"),
 681                         "bitcoin::blockdata::transaction::Transaction" => Some(")"),
 682                         "bitcoin::blockdata::transaction::OutPoint" => Some(")"),
 683                         "bitcoin::blockdata::transaction::TxOut" if !is_ref => Some(")"),
 684                         "bitcoin::blockdata::block::BlockHeader" if is_ref => Some(""),
 685                         "bitcoin::blockdata::block::Block" if is_ref => Some(")"),
 686
 687                         "bitcoin::hash_types::Txid" if !is_ref => Some(".into_inner() }"),
 688
 689                         // Newtypes that we just expose in their original form.
 690                         "bitcoin::hash_types::Txid" if is_ref => Some(".as_inner()"),
 691                         "bitcoin::hash_types::BlockHash" if is_ref => Some(".as_inner()"),
 692                         "bitcoin::hash_types::BlockHash" => Some(".into_inner() }"),
 693                         "bitcoin::secp256k1::Message" if !is_ref => Some(".as_ref().clone() }"),
 694                         "ln::channelmanager::PaymentHash" if is_ref => Some(".0"),
 695                         "ln::channelmanager::PaymentHash" => Some(".0 }"),
 696                         "ln::channelmanager::PaymentPreimage" if is_ref => Some(".0"),
 697                         "ln::channelmanager::PaymentPreimage" => Some(".0 }"),
 698                         "ln::channelmanager::PaymentSecret" if !is_ref => Some(".0 }"),
 699
 700                         // Override the default since Records contain an fmt with a lifetime:
 701                         "util::logger::Record" => Some(".as_ptr()"),
 702
 703                         // List of structs we map (possibly during processing of other files):
 704                         "ln::features::InitFeatures" if is_ref && ptr_for_ref => Some(", is_owned: false }"),
 705                         "ln::features::InitFeatures" if is_ref => Some(", is_owned: false }))"),
 706                         "ln::features::InitFeatures" => Some(")), is_owned: true }"),
 707
 708                         _ => {
 709                                 eprintln!("    Type {} unconvertable to C", full_path);
 710                                 None
 711                         },
 712                 }.map(|s| s.to_owned())
 713         }
 714
 715         fn empty_val_check_suffix_from_path(&self, full_path: &str) -> Option<&str> {
 716                 match full_path {
 717                         "ln::channelmanager::PaymentSecret" => Some(".data == [0; 32]"),
 718                         "bitcoin::secp256k1::key::PublicKey" => Some(".is_null()"),
 719                         "bitcoin::secp256k1::Signature" => Some(".is_null()"),
 720                         _ => None
 721                 }
 722         }
 723
 724         // ****************************
 725         // *** Container Processing ***
 726         // ****************************
 727
 728         /// Returns the module path in the generated mapping crate to the containers which we generate
 729         /// when writing to CrateTypes::template_file.
 730         pub fn generated_container_path() -> &'static str {
 731                 "crate::c_types::derived"
 732         }
 733         /// Returns the module path in the generated mapping crate to the container templates, which
 734         /// are then concretized and put in the generated container path/template_file.
 735         fn container_templ_path() -> &'static str {
 736                 "crate::c_types"
 737         }
 738
 739         /// Returns true if this is a "transparent" container, ie an Option or a container which does
 740         /// not require a generated continer class.
 741         fn is_transparent_container(&self, full_path: &str, _is_ref: bool) -> bool {
 742                 full_path == "Option"
 743         }
 744         /// Returns true if this is a known, supported, non-transparent container.
 745         fn is_known_container(&self, full_path: &str, is_ref: bool) -> bool {
 746                 (full_path == "Result" && !is_ref) || (full_path == "Vec" && !is_ref) || full_path.ends_with("Tuple")
 747         }
 748         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)
 749                         // Returns prefix + Vec<(prefix, var-name-to-inline-convert)> + suffix
 750                         // expecting one element in the vec per generic type, each of which is inline-converted
 751                         -> Option<(&'b str, Vec<(String, String)>, &'b str)> {
 752                 match full_path {
 753                         "Result" if !is_ref => {
 754                                 Some(("match ",
 755                                                 vec![(" { Ok(mut o) => crate::c_types::CResultTempl::ok(".to_string(), "o".to_string()),
 756                                                         ("), Err(mut e) => crate::c_types::CResultTempl::err(".to_string(), "e".to_string())],
 757                                                 ") }"))
 758                         },
 759                         "Vec" if !is_ref => {
 760                                 Some(("Vec::new(); for item in ", vec![(format!(".drain(..) {{ local_{}.push(", var_name), "item".to_string())], "); }"))
 761                         },
 762                         "Slice" => {
 763                                 Some(("Vec::new(); for item in ", vec![(format!(".iter() {{ local_{}.push(", var_name), "**item".to_string())], "); }"))
 764                         },
 765                         "Option" => {
 766                                 if let Some(syn::Type::Path(p)) = single_contained {
 767                                         if self.c_type_has_inner_from_path(&self.resolve_path(&p.path, generics)) {
 768                                                 if is_ref {
 769                                                         return Some(("if ", vec![
 770                                                                 (".is_none() { std::ptr::null() } else { ".to_owned(), format!("({}.as_ref().unwrap())", var_access))
 771                                                                 ], " }"));
 772                                                 } else {
 773                                                         return Some(("if ", vec![
 774                                                                 (".is_none() { std::ptr::null_mut() } else { ".to_owned(), format!("({}.unwrap())", var_access))
 775                                                                 ], " }"));
 776                                                 }
 777                                         }
 778                                 }
 779                                 if let Some(t) = single_contained {
 780                                         let mut v = Vec::new();
 781                                         self.write_empty_rust_val(generics, &mut v, t);
 782                                         let s = String::from_utf8(v).unwrap();
 783                                         return Some(("if ", vec![
 784                                                 (format!(".is_none() {{ {} }} else {{ ", s), format!("({}.unwrap())", var_access))
 785                                                 ], " }"));
 786                                 } else { unreachable!(); }
 787                         },
 788                         _ => None,
 789                 }
 790         }
 791
 792         /// only_contained_has_inner implies that there is only one contained element in the container
 793         /// and it has an inner field (ie is an "opaque" type we've defined).
 794         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)
 795                         // Returns prefix + Vec<(prefix, var-name-to-inline-convert)> + suffix
 796                         // expecting one element in the vec per generic type, each of which is inline-converted
 797                         -> Option<(&'b str, Vec<(String, String)>, &'b str)> {
 798                 match full_path {
 799                         "Result" if !is_ref => {
 800                                 Some(("match ",
 801                                                 vec![(".result_ok { true => Ok(".to_string(), format!("(*unsafe {{ Box::from_raw(<*mut _>::take_ptr(&mut {}.contents.result)) }})", var_name)),
 802                                                      ("), false => Err(".to_string(), format!("(*unsafe {{ Box::from_raw(<*mut _>::take_ptr(&mut {}.contents.err)) }})", var_name))],
 803                                                 ")}"))
 804                         },
 805                         "Vec"|"Slice" if !is_ref => {
 806                                 Some(("Vec::new(); for mut item in ", vec![(format!(".into_rust().drain(..) {{ local_{}.push(", var_name), "item".to_string())], "); }"))
 807                         },
 808                         "Slice" if is_ref => {
 809                                 Some(("Vec::new(); for mut item in ", vec![(format!(".as_slice().iter() {{ local_{}.push(", var_name), "item".to_string())], "); }"))
 810                         },
 811                         "Option" => {
 812                                 if let Some(syn::Type::Path(p)) = single_contained {
 813                                         if self.c_type_has_inner_from_path(&self.resolve_path(&p.path, generics)) {
 814                                                 if is_ref {
 815                                                         return Some(("if ", vec![(".inner.is_null() { None } else { Some((*".to_string(), format!("{}", var_name))], ").clone()) }"))
 816                                                 } else {
 817                                                         return Some(("if ", vec![(".inner.is_null() { None } else { Some(".to_string(), format!("{}", var_name))], ") }"));
 818                                                 }
 819                                         }
 820                                 }
 821
 822                                 if let Some(t) = single_contained {
 823                                         let mut v = Vec::new();
 824                                         let ret_ref = self.write_empty_rust_val_check_suffix(generics, &mut v, t);
 825                                         let s = String::from_utf8(v).unwrap();
 826                                         match ret_ref {
 827                                                 EmptyValExpectedTy::ReferenceAsPointer =>
 828                                                         return Some(("if ", vec![
 829                                                                 (format!("{} {{ None }} else {{ Some(", s), format!("unsafe {{ &mut *{} }}", var_access))
 830                                                         ], ") }")),
 831                                                 EmptyValExpectedTy::OwnedPointer =>
 832                                                         return Some(("if ", vec![
 833                                                                 (format!("{} {{ None }} else {{ Some(", s), format!("unsafe {{ *Box::from_raw({}) }}", var_access))
 834                                                         ], ") }")),
 835                                                 EmptyValExpectedTy::NonPointer =>
 836                                                         return Some(("if ", vec![
 837                                                                 (format!("{} {{ None }} else {{ Some(", s), format!("{}", var_access))
 838                                                         ], ") }")),
 839                                         }
 840                                 } else { unreachable!(); }
 841                         },
 842                         _ => None,
 843                 }
 844         }
 845
 846         // *************************************************
 847         // *** Type definition during main.rs processing ***
 848         // *************************************************
 849
 850         fn process_use_intern<W: std::io::Write>(&mut self, w: &mut W, u: &syn::UseTree, partial_path: &str) {
 851                 match u {
 852                         syn::UseTree::Path(p) => {
 853                                 let new_path = format!("{}::{}", partial_path, p.ident);
 854                                 self.process_use_intern(w, &p.tree, &new_path);
 855                         },
 856                         syn::UseTree::Name(n) => {
 857                                 let full_path = format!("{}::{}", partial_path, n.ident);
 858                                 self.imports.insert(n.ident.clone(), full_path);
 859                         },
 860                         syn::UseTree::Group(g) => {
 861                                 for i in g.items.iter() {
 862                                         self.process_use_intern(w, i, partial_path);
 863                                 }
 864                         },
 865                         syn::UseTree::Rename(r) => {
 866                                 let full_path = format!("{}::{}", partial_path, r.ident);
 867                                 self.imports.insert(r.rename.clone(), full_path);
 868                         },
 869                         syn::UseTree::Glob(_) => {
 870                                 eprintln!("Ignoring * use for {} - this may result in resolution failures", partial_path);
 871                         },
 872                 }
 873         }
 874         pub fn process_use<W: std::io::Write>(&mut self, w: &mut W, u: &syn::ItemUse) {
 875                 if let syn::Visibility::Public(_) = u.vis {
 876                         // We actually only use these for #[cfg(fuzztarget)]
 877                         eprintln!("Ignoring pub(use) tree!");
 878                         return;
 879                 }
 880                 match &u.tree {
 881                         syn::UseTree::Path(p) => {
 882                                 let new_path = format!("{}", p.ident);
 883                                 self.process_use_intern(w, &p.tree, &new_path);
 884                         },
 885                         syn::UseTree::Name(n) => {
 886                                 let full_path = format!("{}", n.ident);
 887                                 self.imports.insert(n.ident.clone(), full_path);
 888                         },
 889                         _ => unimplemented!(),
 890                 }
 891                 if u.leading_colon.is_some() { unimplemented!() }
 892         }
 893
 894         pub fn mirrored_enum_declared(&mut self, ident: &syn::Ident) {
 895                 eprintln!("{} mirrored", ident);
 896                 self.declared.insert(ident.clone(), DeclType::MirroredEnum);
 897         }
 898         pub fn enum_ignored(&mut self, ident: &'c syn::Ident) {
 899                 self.declared.insert(ident.clone(), DeclType::EnumIgnored);
 900         }
 901         pub fn struct_imported(&mut self, ident: &'c syn::Ident, named: String) {
 902                 eprintln!("Imported {} as {}", ident, named);
 903                 self.declared.insert(ident.clone(), DeclType::StructImported);
 904         }
 905         pub fn struct_ignored(&mut self, ident: &syn::Ident) {
 906                 eprintln!("Not importing {}", ident);
 907                 self.declared.insert(ident.clone(), DeclType::StructIgnored);
 908         }
 909         pub fn trait_declared(&mut self, ident: &syn::Ident, t: &'c syn::ItemTrait) {
 910                 eprintln!("Trait {} created", ident);
 911                 self.declared.insert(ident.clone(), DeclType::Trait(t));
 912         }
 913         pub fn get_declared_type(&'a self, ident: &syn::Ident) -> Option<&'a DeclType<'c>> {
 914                 self.declared.get(ident)
 915         }
 916         /// Returns true if the object at the given path is mapped as X { inner: *mut origX, .. }.
 917         pub fn c_type_has_inner_from_path(&self, full_path: &str) -> bool{
 918                 self.crate_types.opaques.get(full_path).is_some()
 919         }
 920
 921         pub fn maybe_resolve_ident(&self, id: &syn::Ident) -> Option<String> {
 922                 if let Some(imp) = self.imports.get(id) {
 923                         Some(imp.clone())
 924                 } else if self.declared.get(id).is_some() {
 925                         Some(self.module_path.to_string() + "::" + &format!("{}", id))
 926                 } else { None }
 927         }
 928
 929         pub fn maybe_resolve_non_ignored_ident(&self, id: &syn::Ident) -> Option<String> {
 930                 if let Some(imp) = self.imports.get(id) {
 931                         Some(imp.clone())
 932                 } else if let Some(decl_type) = self.declared.get(id) {
 933                         match decl_type {
 934                                 DeclType::StructIgnored => None,
 935                                 _ => Some(self.module_path.to_string() + "::" + &format!("{}", id)),
 936                         }
 937                 } else { None }
 938         }
 939
 940         pub fn maybe_resolve_path(&self, p_arg: &syn::Path, generics: Option<&GenericTypes>) -> Option<String> {
 941                 let p = if let Some(gen_types) = generics {
 942                         if let Some((_, synpath)) = gen_types.maybe_resolve_path(p_arg) {
 943                                 synpath
 944                         } else { p_arg }
 945                 } else { p_arg };
 946
 947                 if p.leading_colon.is_some() {
 948                         Some(p.segments.iter().enumerate().map(|(idx, seg)| {
 949                                 format!("{}{}", if idx == 0 { "" } else { "::" }, seg.ident)
 950                         }).collect())
 951                 } else if let Some(id) = p.get_ident() {
 952                         self.maybe_resolve_ident(id)
 953                 } else {
 954                         if p.segments.len() == 1 {
 955                                 let seg = p.segments.iter().next().unwrap();
 956                                 return self.maybe_resolve_ident(&seg.ident);
 957                         }
 958                         let mut seg_iter = p.segments.iter();
 959                         let first_seg = seg_iter.next().unwrap();
 960                         let remaining: String = seg_iter.map(|seg| {
 961                                 format!("::{}", seg.ident)
 962                         }).collect();
 963                         if let Some(imp) = self.imports.get(&first_seg.ident) {
 964                                 if remaining != "" {
 965                                         Some(imp.clone() + &remaining)
 966                                 } else {
 967                                         Some(imp.clone())
 968                                 }
 969                         } else { None }
 970                 }
 971         }
 972         pub fn resolve_path(&self, p: &syn::Path, generics: Option<&GenericTypes>) -> String {
 973                 self.maybe_resolve_path(p, generics).unwrap()
 974         }
 975
 976         // ***********************************
 977         // *** Original Rust Type Printing ***
 978         // ***********************************
 979
 980         fn in_rust_prelude(resolved_path: &str) -> bool {
 981                 match resolved_path {
 982                         "Vec" => true,
 983                         "Result" => true,
 984                         "Option" => true,
 985                         _ => false,
 986                 }
 987         }
 988
 989         fn write_rust_path<W: std::io::Write>(&self, w: &mut W, generics_resolver: Option<&GenericTypes>, path: &syn::Path) {
 990                 if let Some(resolved) = self.maybe_resolve_path(&path, generics_resolver) {
 991                         if self.is_primitive(&resolved) {
 992                                 write!(w, "{}", path.get_ident().unwrap()).unwrap();
 993                         } else {
 994                                 // TODO: We should have a generic "is from a dependency" check here instead of
 995                                 // checking for "bitcoin" explicitly.
 996                                 if resolved.starts_with("bitcoin::") || Self::in_rust_prelude(&resolved) {
 997                                         write!(w, "{}", resolved).unwrap();
 998                                 // If we're printing a generic argument, it needs to reference the crate, otherwise
 999                                 // the original crate:
1000                                 } else if self.maybe_resolve_path(&path, None).as_ref() == Some(&resolved) {
1001                                         write!(w, "{}::{}", self.orig_crate, resolved).unwrap();
1002                                 } else {
1003                                         write!(w, "crate::{}", resolved).unwrap();
1004                                 }
1005                         }
1006                         if let syn::PathArguments::AngleBracketed(args) = &path.segments.iter().last().unwrap().arguments {
1007                                 self.write_rust_generic_arg(w, generics_resolver, args.args.iter());
1008                         }
1009                 } else {
1010                         if path.leading_colon.is_some() {
1011                                 write!(w, "::").unwrap();
1012                         }
1013                         for (idx, seg) in path.segments.iter().enumerate() {
1014                                 if idx != 0 { write!(w, "::").unwrap(); }
1015                                 write!(w, "{}", seg.ident).unwrap();
1016                                 if let syn::PathArguments::AngleBracketed(args) = &seg.arguments {
1017                                         self.write_rust_generic_arg(w, generics_resolver, args.args.iter());
1018                                 }
1019                         }
1020                 }
1021         }
1022         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>) {
1023                 let mut had_params = false;
1024                 for (idx, arg) in generics.enumerate() {
1025                         if idx != 0 { write!(w, ", ").unwrap(); } else { write!(w, "<").unwrap(); }
1026                         had_params = true;
1027                         match arg {
1028                                 syn::GenericParam::Lifetime(lt) => write!(w, "'{}", lt.lifetime.ident).unwrap(),
1029                                 syn::GenericParam::Type(t) => {
1030                                         write!(w, "{}", t.ident).unwrap();
1031                                         if t.colon_token.is_some() { write!(w, ":").unwrap(); }
1032                                         for (idx, bound) in t.bounds.iter().enumerate() {
1033                                                 if idx != 0 { write!(w, " + ").unwrap(); }
1034                                                 match bound {
1035                                                         syn::TypeParamBound::Trait(tb) => {
1036                                                                 if tb.paren_token.is_some() || tb.lifetimes.is_some() { unimplemented!(); }
1037                                                                 self.write_rust_path(w, generics_resolver, &tb.path);
1038                                                         },
1039                                                         _ => unimplemented!(),
1040                                                 }
1041                                         }
1042                                         if t.eq_token.is_some() || t.default.is_some() { unimplemented!(); }
1043                                 },
1044                                 _ => unimplemented!(),
1045                         }
1046                 }
1047                 if had_params { write!(w, ">").unwrap(); }
1048         }
1049
1050         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>) {
1051                 write!(w, "<").unwrap();
1052                 for (idx, arg) in generics.enumerate() {
1053                         if idx != 0 { write!(w, ", ").unwrap(); }
1054                         match arg {
1055                                 syn::GenericArgument::Type(t) => self.write_rust_type(w, generics_resolver, t),
1056                                 _ => unimplemented!(),
1057                         }
1058                 }
1059                 write!(w, ">").unwrap();
1060         }
1061         pub fn write_rust_type<W: std::io::Write>(&self, w: &mut W, generics: Option<&GenericTypes>, t: &syn::Type) {
1062                 match t {
1063                         syn::Type::Path(p) => {
1064                                 if p.qself.is_some() {
1065                                         unimplemented!();
1066                                 }
1067                                 self.write_rust_path(w, generics, &p.path);
1068                         },
1069                         syn::Type::Reference(r) => {
1070                                 write!(w, "&").unwrap();
1071                                 if let Some(lft) = &r.lifetime {
1072                                         write!(w, "'{} ", lft.ident).unwrap();
1073                                 }
1074                                 if r.mutability.is_some() {
1075                                         write!(w, "mut ").unwrap();
1076                                 }
1077                                 self.write_rust_type(w, generics, &*r.elem);
1078                         },
1079                         syn::Type::Array(a) => {
1080                                 write!(w, "[").unwrap();
1081                                 self.write_rust_type(w, generics, &a.elem);
1082                                 if let syn::Expr::Lit(l) = &a.len {
1083                                         if let syn::Lit::Int(i) = &l.lit {
1084                                                 write!(w, "; {}]", i).unwrap();
1085                                         } else { unimplemented!(); }
1086                                 } else { unimplemented!(); }
1087                         }
1088                         syn::Type::Slice(s) => {
1089                                 write!(w, "[").unwrap();
1090                                 self.write_rust_type(w, generics, &s.elem);
1091                                 write!(w, "]").unwrap();
1092                         },
1093                         syn::Type::Tuple(s) => {
1094                                 write!(w, "(").unwrap();
1095                                 for (idx, t) in s.elems.iter().enumerate() {
1096                                         if idx != 0 { write!(w, ", ").unwrap(); }
1097                                         self.write_rust_type(w, generics, &t);
1098                                 }
1099                                 write!(w, ")").unwrap();
1100                         },
1101                         _ => unimplemented!(),
1102                 }
1103         }
1104
1105         /// Prints a constructor for something which is "uninitialized" (but obviously not actually
1106         /// unint'd memory).
1107         pub fn write_empty_rust_val<W: std::io::Write>(&self, generics: Option<&GenericTypes>, w: &mut W, t: &syn::Type) {
1108                 match t {
1109                         syn::Type::Path(p) => {
1110                                 let resolved = self.resolve_path(&p.path, generics);
1111                                 if self.crate_types.opaques.get(&resolved).is_some() {
1112                                         write!(w, "crate::{} {{ inner: std::ptr::null_mut(), is_owned: true }}", resolved).unwrap();
1113                                 } else {
1114                                         // Assume its a manually-mapped C type, where we can just define an null() fn
1115                                         write!(w, "{}::null()", self.c_type_from_path(&resolved, false, false).unwrap()).unwrap();
1116                                 }
1117                         },
1118                         syn::Type::Array(a) => {
1119                                 if let syn::Expr::Lit(l) = &a.len {
1120                                         if let syn::Lit::Int(i) = &l.lit {
1121                                                 if i.base10_digits().parse::<usize>().unwrap() < 32 {
1122                                                         // Blindly assume that if we're trying to create an empty value for an
1123                                                         // array < 32 entries that all-0s may be a valid state.
1124                                                         unimplemented!();
1125                                                 }
1126                                                 let arrty = format!("[u8; {}]", i.base10_digits());
1127                                                 write!(w, "{}", self.to_c_conversion_inline_prefix_from_path(&arrty, false, false).unwrap()).unwrap();
1128                                                 write!(w, "[0; {}]", i.base10_digits()).unwrap();
1129                                                 write!(w, "{}", self.to_c_conversion_inline_suffix_from_path(&arrty, false, false).unwrap()).unwrap();
1130                                         } else { unimplemented!(); }
1131                                 } else { unimplemented!(); }
1132                         }
1133                         _ => unimplemented!(),
1134                 }
1135         }
1136
1137         /// Prints a suffix to determine if a variable is empty (ie was set by write_empty_rust_val).
1138         /// See EmptyValExpectedTy for information on return types.
1139         fn write_empty_rust_val_check_suffix<W: std::io::Write>(&self, generics: Option<&GenericTypes>, w: &mut W, t: &syn::Type) -> EmptyValExpectedTy {
1140                 match t {
1141                         syn::Type::Path(p) => {
1142                                 let resolved = self.resolve_path(&p.path, generics);
1143                                 if self.crate_types.opaques.get(&resolved).is_some() {
1144                                         write!(w, ".inner.is_null()").unwrap();
1145                                         EmptyValExpectedTy::NonPointer
1146                                 } else {
1147                                         if let Some(suffix) = self.empty_val_check_suffix_from_path(&resolved) {
1148                                                 write!(w, "{}", suffix).unwrap();
1149                                                 // We may eventually need to allow empty_val_check_suffix_from_path to specify if we need a deref or not
1150                                                 EmptyValExpectedTy::NonPointer
1151                                         } else {
1152                                                 write!(w, " == std::ptr::null_mut()").unwrap();
1153                                                 EmptyValExpectedTy::OwnedPointer
1154                                         }
1155                                 }
1156                         },
1157                         syn::Type::Array(a) => {
1158                                 if let syn::Expr::Lit(l) = &a.len {
1159                                         if let syn::Lit::Int(i) = &l.lit {
1160                                                 write!(w, " == [0; {}]", i.base10_digits()).unwrap();
1161                                                 EmptyValExpectedTy::NonPointer
1162                                         } else { unimplemented!(); }
1163                                 } else { unimplemented!(); }
1164                         },
1165                         syn::Type::Slice(_) => {
1166                                 // Option<[]> always implies that we want to treat len() == 0 differently from
1167                                 // None, so we always map an Option<[]> into a pointer.
1168                                 write!(w, " == std::ptr::null_mut()").unwrap();
1169                                 EmptyValExpectedTy::ReferenceAsPointer
1170                         },
1171                         _ => unimplemented!(),
1172                 }
1173         }
1174
1175         /// Prints a suffix to determine if a variable is empty (ie was set by write_empty_rust_val).
1176         pub fn write_empty_rust_val_check<W: std::io::Write>(&self, generics: Option<&GenericTypes>, w: &mut W, t: &syn::Type, var_access: &str) {
1177                 match t {
1178                         syn::Type::Path(_) => {
1179                                 write!(w, "{}", var_access).unwrap();
1180                                 self.write_empty_rust_val_check_suffix(generics, w, t);
1181                         },
1182                         syn::Type::Array(a) => {
1183                                 if let syn::Expr::Lit(l) = &a.len {
1184                                         if let syn::Lit::Int(i) = &l.lit {
1185                                                 let arrty = format!("[u8; {}]", i.base10_digits());
1186                                                 // We don't (yet) support a new-var conversion here.
1187                                                 assert!(self.from_c_conversion_new_var_from_path(&arrty, false).is_none());
1188                                                 write!(w, "{}{}{}",
1189                                                         self.from_c_conversion_prefix_from_path(&arrty, false).unwrap(),
1190                                                         var_access,
1191                                                         self.from_c_conversion_suffix_from_path(&arrty, false).unwrap()).unwrap();
1192                                                 self.write_empty_rust_val_check_suffix(generics, w, t);
1193                                         } else { unimplemented!(); }
1194                                 } else { unimplemented!(); }
1195                         }
1196                         _ => unimplemented!(),
1197                 }
1198         }
1199
1200         // ********************************
1201         // *** Type conversion printing ***
1202         // ********************************
1203
1204         /// Returns true we if can just skip passing this to C entirely
1205         pub fn skip_arg(&self, t: &syn::Type, generics: Option<&GenericTypes>) -> bool {
1206                 match t {
1207                         syn::Type::Path(p) => {
1208                                 if p.qself.is_some() { unimplemented!(); }
1209                                 if let Some(full_path) = self.maybe_resolve_path(&p.path, generics) {
1210                                         self.skip_path(&full_path)
1211                                 } else { false }
1212                         },
1213                         syn::Type::Reference(r) => {
1214                                 self.skip_arg(&*r.elem, generics)
1215                         },
1216                         _ => false,
1217                 }
1218         }
1219         pub fn no_arg_to_rust<W: std::io::Write>(&self, w: &mut W, t: &syn::Type, generics: Option<&GenericTypes>) {
1220                 match t {
1221                         syn::Type::Path(p) => {
1222                                 if p.qself.is_some() { unimplemented!(); }
1223                                 if let Some(full_path) = self.maybe_resolve_path(&p.path, generics) {
1224                                         write!(w, "{}", self.no_arg_path_to_rust(&full_path)).unwrap();
1225                                 }
1226                         },
1227                         syn::Type::Reference(r) => {
1228                                 self.no_arg_to_rust(w, &*r.elem, generics);
1229                         },
1230                         _ => {},
1231                 }
1232         }
1233
1234         fn write_conversion_inline_intern<W: std::io::Write,
1235                         LP: Fn(&str, bool, bool) -> Option<String>, DL: Fn(&mut W, &DeclType, &str, bool, bool), SC: Fn(bool) -> &'static str>
1236                         (&self, w: &mut W, t: &syn::Type, generics: Option<&GenericTypes>, is_ref: bool, is_mut: bool, ptr_for_ref: bool,
1237                          tupleconv: &str, prefix: bool, sliceconv: SC, path_lookup: LP, decl_lookup: DL) {
1238                 match t {
1239                         syn::Type::Reference(r) => {
1240                                 self.write_conversion_inline_intern(w, &*r.elem, generics, true, r.mutability.is_some(),
1241                                         ptr_for_ref, tupleconv, prefix, sliceconv, path_lookup, decl_lookup);
1242                         },
1243                         syn::Type::Path(p) => {
1244                                 if p.qself.is_some() {
1245                                         unimplemented!();
1246                                 }
1247
1248                                 let resolved_path = self.resolve_path(&p.path, generics);
1249                                 if let Some(aliased_type) = self.crate_types.type_aliases.get(&resolved_path) {
1250                                         return self.write_conversion_inline_intern(w, aliased_type, None, is_ref, is_mut, ptr_for_ref, tupleconv, prefix, sliceconv, path_lookup, decl_lookup);
1251                                 } else if let Some(c_type) = path_lookup(&resolved_path, is_ref, ptr_for_ref) {
1252                                         write!(w, "{}", c_type).unwrap();
1253                                 } else if self.crate_types.opaques.get(&resolved_path).is_some() {
1254                                         decl_lookup(w, &DeclType::StructImported, &resolved_path, is_ref, is_mut);
1255                                 } else if self.crate_types.mirrored_enums.get(&resolved_path).is_some() {
1256                                         decl_lookup(w, &DeclType::MirroredEnum, &resolved_path, is_ref, is_mut);
1257                                 } else if let Some(t) = self.crate_types.traits.get(&resolved_path) {
1258                                         decl_lookup(w, &DeclType::Trait(t), &resolved_path, is_ref, is_mut);
1259                                 } else if let Some(ident) = single_ident_generic_path_to_ident(&p.path) {
1260                                         if let Some(_) = self.imports.get(ident) {
1261                                                 // crate_types lookup has to have succeeded:
1262                                                 panic!("Failed to print inline conversion for {}", ident);
1263                                         } else if let Some(decl_type) = self.declared.get(ident) {
1264                                                 decl_lookup(w, decl_type, &self.maybe_resolve_ident(ident).unwrap(), is_ref, is_mut);
1265                                         } else { unimplemented!(); }
1266                                 } else { unimplemented!(); }
1267                         },
1268                         syn::Type::Array(a) => {
1269                                 // We assume all arrays contain only [int_literal; X]s.
1270                                 // This may result in some outputs not compiling.
1271                                 if let syn::Expr::Lit(l) = &a.len {
1272                                         if let syn::Lit::Int(i) = &l.lit {
1273                                                 write!(w, "{}", path_lookup(&format!("[u8; {}]", i.base10_digits()), is_ref, ptr_for_ref).unwrap()).unwrap();
1274                                         } else { unimplemented!(); }
1275                                 } else { unimplemented!(); }
1276                         },
1277                         syn::Type::Slice(s) => {
1278                                 // We assume all slices contain only literals or references.
1279                                 // This may result in some outputs not compiling.
1280                                 if let syn::Type::Path(p) = &*s.elem {
1281                                         let resolved = self.resolve_path(&p.path, generics);
1282                                         assert!(self.is_primitive(&resolved));
1283                                         write!(w, "{}", path_lookup("[u8]", is_ref, ptr_for_ref).unwrap()).unwrap();
1284                                 } else if let syn::Type::Reference(r) = &*s.elem {
1285                                         if let syn::Type::Path(p) = &*r.elem {
1286                                                 write!(w, "{}", sliceconv(self.c_type_has_inner_from_path(&self.resolve_path(&p.path, generics)))).unwrap();
1287                                         } else { unimplemented!(); }
1288                                 } else if let syn::Type::Tuple(t) = &*s.elem {
1289                                         assert!(!t.elems.is_empty());
1290                                         if prefix {
1291                                                 write!(w, "&local_").unwrap();
1292                                         } else {
1293                                                 let mut needs_map = false;
1294                                                 for e in t.elems.iter() {
1295                                                         if let syn::Type::Reference(_) = e {
1296                                                                 needs_map = true;
1297                                                         }
1298                                                 }
1299                                                 if needs_map {
1300                                                         write!(w, ".iter().map(|(").unwrap();
1301                                                         for i in 0..t.elems.len() {
1302                                                                 write!(w, "{}{}", if i != 0 { ", " } else { "" }, ('a' as u8 + i as u8) as char).unwrap();
1303                                                         }
1304                                                         write!(w, ")| (").unwrap();
1305                                                         for (idx, e) in t.elems.iter().enumerate() {
1306                                                                 if let syn::Type::Reference(_) = e {
1307                                                                         write!(w, "{}{}", if idx != 0 { ", " } else { "" }, (idx as u8 + 'a' as u8) as char).unwrap();
1308                                                                 } else if let syn::Type::Path(_) = e {
1309                                                                         write!(w, "{}*{}", if idx != 0 { ", " } else { "" }, (idx as u8 + 'a' as u8) as char).unwrap();
1310                                                                 } else { unimplemented!(); }
1311                                                         }
1312                                                         write!(w, ")).collect::<Vec<_>>()[..]").unwrap();
1313                                                 }
1314                                         }
1315                                 } else { unimplemented!(); }
1316                         },
1317                         syn::Type::Tuple(t) => {
1318                                 if t.elems.is_empty() {
1319                                         // cbindgen has poor support for (), see, eg https://github.com/eqrion/cbindgen/issues/527
1320                                         // so work around it by just pretending its a 0u8
1321                                         write!(w, "{}", tupleconv).unwrap();
1322                                 } else {
1323                                         if prefix { write!(w, "local_").unwrap(); }
1324                                 }
1325                         },
1326                         _ => unimplemented!(),
1327                 }
1328         }
1329
1330         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) {
1331                 self.write_conversion_inline_intern(w, t, generics, is_ref, false, ptr_for_ref, "0u8 /*", true, |_| "local_",
1332                                 |a, b, c| self.to_c_conversion_inline_prefix_from_path(a, b, c),
1333                                 |w, decl_type, decl_path, is_ref, _is_mut| {
1334                                         match decl_type {
1335                                                 DeclType::MirroredEnum if is_ref && ptr_for_ref => write!(w, "crate::{}::from_native(&", decl_path).unwrap(),
1336                                                 DeclType::MirroredEnum if is_ref => write!(w, "&crate::{}::from_native(&", decl_path).unwrap(),
1337                                                 DeclType::MirroredEnum => write!(w, "crate::{}::native_into(", decl_path).unwrap(),
1338                                                 DeclType::EnumIgnored|DeclType::StructImported if is_ref && ptr_for_ref && from_ptr =>
1339                                                         write!(w, "crate::{} {{ inner: unsafe {{ (", decl_path).unwrap(),
1340                                                 DeclType::EnumIgnored|DeclType::StructImported if is_ref && ptr_for_ref =>
1341                                                         write!(w, "crate::{} {{ inner: unsafe {{ ( (&(", decl_path).unwrap(),
1342                                                 DeclType::EnumIgnored|DeclType::StructImported if is_ref =>
1343                                                         write!(w, "&crate::{} {{ inner: unsafe {{ (", decl_path).unwrap(),
1344                                                 DeclType::EnumIgnored|DeclType::StructImported if !is_ref && from_ptr =>
1345                                                         write!(w, "crate::{} {{ inner: ", decl_path).unwrap(),
1346                                                 DeclType::EnumIgnored|DeclType::StructImported if !is_ref =>
1347                                                         write!(w, "crate::{} {{ inner: Box::into_raw(Box::new(", decl_path).unwrap(),
1348                                                 DeclType::Trait(_) if is_ref => write!(w, "&").unwrap(),
1349                                                 DeclType::Trait(_) if !is_ref => {},
1350                                                 _ => panic!("{:?}", decl_path),
1351                                         }
1352                                 });
1353         }
1354         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) {
1355                 self.write_to_c_conversion_inline_prefix_inner(w, t, generics, false, ptr_for_ref, false);
1356         }
1357         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) {
1358                 self.write_conversion_inline_intern(w, t, generics, is_ref, false, ptr_for_ref, "*/", false, |_| ".into()",
1359                                 |a, b, c| self.to_c_conversion_inline_suffix_from_path(a, b, c),
1360                                 |w, decl_type, _full_path, is_ref, _is_mut| match decl_type {
1361                                         DeclType::MirroredEnum => write!(w, ")").unwrap(),
1362                                         DeclType::EnumIgnored|DeclType::StructImported if is_ref && ptr_for_ref && from_ptr =>
1363                                                 write!(w, " as *const _) as *mut _ }}, is_owned: false }}").unwrap(),
1364                                         DeclType::EnumIgnored|DeclType::StructImported if is_ref && ptr_for_ref =>
1365                                                 write!(w, ") as *const _) as *mut _) }}, is_owned: false }}").unwrap(),
1366                                         DeclType::EnumIgnored|DeclType::StructImported if is_ref =>
1367                                                 write!(w, " as *const _) as *mut _ }}, is_owned: false }}").unwrap(),
1368                                         DeclType::EnumIgnored|DeclType::StructImported if !is_ref && from_ptr =>
1369                                                 write!(w, ", is_owned: true }}").unwrap(),
1370                                         DeclType::EnumIgnored|DeclType::StructImported if !is_ref => write!(w, ")), is_owned: true }}").unwrap(),
1371                                         DeclType::Trait(_) if is_ref => {},
1372                                         DeclType::Trait(_) => {
1373                                                 // This is used when we're converting a concrete Rust type into a C trait
1374                                                 // for use when a Rust trait method returns an associated type.
1375                                                 // Because all of our C traits implement From<RustTypesImplementingTraits>
1376                                                 // we can just call .into() here and be done.
1377                                                 write!(w, ".into()").unwrap()
1378                                         },
1379                                         _ => unimplemented!(),
1380                                 });
1381         }
1382         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) {
1383                 self.write_to_c_conversion_inline_suffix_inner(w, t, generics, false, ptr_for_ref, false);
1384         }
1385
1386         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) {
1387                 self.write_conversion_inline_intern(w, t, generics, is_ref, false, false, "() /*", true, |_| "&local_",
1388                                 |a, b, _c| self.from_c_conversion_prefix_from_path(a, b),
1389                                 |w, decl_type, _full_path, is_ref, is_mut| match decl_type {
1390                                         DeclType::StructImported if is_ref && ptr_for_ref => write!(w, "unsafe {{ &*(*").unwrap(),
1391                                         DeclType::StructImported if is_mut && is_ref => write!(w, "unsafe {{ &mut *").unwrap(),
1392                                         DeclType::StructImported if is_ref => write!(w, "unsafe {{ &*").unwrap(),
1393                                         DeclType::StructImported if !is_ref => write!(w, "*unsafe {{ Box::from_raw(").unwrap(),
1394                                         DeclType::MirroredEnum if is_ref => write!(w, "&").unwrap(),
1395                                         DeclType::MirroredEnum => {},
1396                                         DeclType::Trait(_) => {},
1397                                         _ => unimplemented!(),
1398                                 });
1399         }
1400         pub fn write_from_c_conversion_prefix<W: std::io::Write>(&self, w: &mut W, t: &syn::Type, generics: Option<&GenericTypes>) {
1401                 self.write_from_c_conversion_prefix_inner(w, t, generics, false, false);
1402         }
1403         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) {
1404                 self.write_conversion_inline_intern(w, t, generics, is_ref, false, false, "*/", false,
1405                                 |has_inner| match has_inner {
1406                                         false => ".iter().collect::<Vec<_>>()[..]",
1407                                         true => "[..]",
1408                                 },
1409                                 |a, b, _c| self.from_c_conversion_suffix_from_path(a, b),
1410                                 |w, decl_type, _full_path, is_ref, _is_mut| match decl_type {
1411                                         DeclType::StructImported if is_ref && ptr_for_ref => write!(w, ").inner }}").unwrap(),
1412                                         DeclType::StructImported if is_ref => write!(w, ".inner }}").unwrap(),
1413                                         DeclType::StructImported if !is_ref => write!(w, ".take_inner()) }}").unwrap(),
1414                                         DeclType::MirroredEnum if is_ref => write!(w, ".to_native()").unwrap(),
1415                                         DeclType::MirroredEnum => write!(w, ".into_native()").unwrap(),
1416                                         DeclType::Trait(_) => {},
1417                                         _ => unimplemented!(),
1418                                 });
1419         }
1420         pub fn write_from_c_conversion_suffix<W: std::io::Write>(&self, w: &mut W, t: &syn::Type, generics: Option<&GenericTypes>) {
1421                 self.write_from_c_conversion_suffix_inner(w, t, generics, false, false);
1422         }
1423         // Note that compared to the above conversion functions, the following two are generally
1424         // significantly undertested:
1425         pub fn write_from_c_conversion_to_ref_prefix<W: std::io::Write>(&self, w: &mut W, t: &syn::Type, generics: Option<&GenericTypes>) {
1426                 self.write_conversion_inline_intern(w, t, generics, false, false, false, "() /*", true, |_| "&local_",
1427                                 |a, b, _c| {
1428                                         if let Some(conv) = self.from_c_conversion_prefix_from_path(a, b) {
1429                                                 Some(format!("&{}", conv))
1430                                         } else { None }
1431                                 },
1432                                 |w, decl_type, _full_path, is_ref, _is_mut| match decl_type {
1433                                         DeclType::StructImported if !is_ref => write!(w, "unsafe {{ &*").unwrap(),
1434                                         _ => unimplemented!(),
1435                                 });
1436         }
1437         pub fn write_from_c_conversion_to_ref_suffix<W: std::io::Write>(&self, w: &mut W, t: &syn::Type, generics: Option<&GenericTypes>) {
1438                 self.write_conversion_inline_intern(w, t, generics, false, false, false, "*/", false,
1439                                 |has_inner| match has_inner {
1440                                         false => ".iter().collect::<Vec<_>>()[..]",
1441                                         true => "[..]",
1442                                 },
1443                                 |a, b, _c| self.from_c_conversion_suffix_from_path(a, b),
1444                                 |w, decl_type, _full_path, is_ref, _is_mut| match decl_type {
1445                                         DeclType::StructImported if !is_ref => write!(w, ".inner }}").unwrap(),
1446                                         _ => unimplemented!(),
1447                                 });
1448         }
1449
1450         fn write_conversion_new_var_intern<'b, W: std::io::Write,
1451                 LP: Fn(&str, bool) -> Option<(&str, &str)>,
1452                 LC: Fn(&str, bool, Option<&syn::Type>, &syn::Ident, &str) ->  Option<(&'b str, Vec<(String, String)>, &'b str)>,
1453                 VP: Fn(&mut W, &syn::Type, Option<&GenericTypes>, bool, bool, bool),
1454                 VS: Fn(&mut W, &syn::Type, Option<&GenericTypes>, bool, bool, bool)>
1455                         (&self, w: &mut W, ident: &syn::Ident, var: &str, t: &syn::Type, generics: Option<&GenericTypes>,
1456                          mut is_ref: bool, mut ptr_for_ref: bool, to_c: bool,
1457                          path_lookup: &LP, container_lookup: &LC, var_prefix: &VP, var_suffix: &VS) -> bool {
1458
1459                 macro_rules! convert_container {
1460                         ($container_type: expr, $args_len: expr, $args_iter: expr) => { {
1461                                 // For slices (and Options), we refuse to directly map them as is_ref when they
1462                                 // aren't opaque types containing an inner pointer. This is due to the fact that,
1463                                 // in both cases, the actual higher-level type is non-is_ref.
1464                                 let ty_has_inner = if self.is_transparent_container(&$container_type, is_ref) || $container_type == "Slice" {
1465                                         let ty = $args_iter().next().unwrap();
1466                                         if $container_type == "Slice" && to_c {
1467                                                 // "To C ptr_for_ref" means "return the regular object with is_owned
1468                                                 // set to false", which is totally what we want in a slice if we're about to
1469                                                 // set ty_has_inner.
1470                                                 ptr_for_ref = true;
1471                                         }
1472                                         if let syn::Type::Reference(t) = ty {
1473                                                 if let syn::Type::Path(p) = &*t.elem {
1474                                                         self.c_type_has_inner_from_path(&self.resolve_path(&p.path, generics))
1475                                                 } else { false }
1476                                         } else if let syn::Type::Path(p) = ty {
1477                                                 self.c_type_has_inner_from_path(&self.resolve_path(&p.path, generics))
1478                                         } else { false }
1479                                 } else { true };
1480
1481                                 // Options get a bunch of special handling, since in general we map Option<>al
1482                                 // types into the same C type as non-Option-wrapped types. This ends up being
1483                                 // pretty manual here and most of the below special-cases are for Options.
1484                                 let mut needs_ref_map = false;
1485                                 let mut only_contained_type = None;
1486                                 let mut only_contained_has_inner = false;
1487                                 let mut contains_slice = false;
1488                                 if $args_len == 1 && self.is_transparent_container(&$container_type, is_ref) {
1489                                         only_contained_has_inner = ty_has_inner;
1490                                         let arg = $args_iter().next().unwrap();
1491                                         if let syn::Type::Reference(t) = arg {
1492                                                 only_contained_type = Some(&*t.elem);
1493                                                 if let syn::Type::Path(_) = &*t.elem {
1494                                                         is_ref = true;
1495                                                 } else if let syn::Type::Slice(_) = &*t.elem {
1496                                                         contains_slice = true;
1497                                                 } else { return false; }
1498                                                 needs_ref_map = true;
1499                                         } else if let syn::Type::Path(_) = arg {
1500                                                 only_contained_type = Some(&arg);
1501                                         } else { unimplemented!(); }
1502                                 }
1503
1504                                 if let Some((prefix, conversions, suffix)) = container_lookup(&$container_type, is_ref && ty_has_inner, only_contained_type, ident, var) {
1505                                         assert_eq!(conversions.len(), $args_len);
1506                                         write!(w, "let mut local_{}{} = ", ident, if !to_c && needs_ref_map {"_base"} else { "" }).unwrap();
1507                                         if only_contained_has_inner && to_c {
1508                                                 var_prefix(w, $args_iter().next().unwrap(), generics, is_ref, ptr_for_ref, true);
1509                                         }
1510                                         write!(w, "{}{}", prefix, var).unwrap();
1511
1512                                         for ((pfx, var_name), (idx, ty)) in conversions.iter().zip($args_iter().enumerate()) {
1513                                                 let mut var = std::io::Cursor::new(Vec::new());
1514                                                 write!(&mut var, "{}", var_name).unwrap();
1515                                                 let var_access = String::from_utf8(var.into_inner()).unwrap();
1516
1517                                                 let conv_ty = if needs_ref_map { only_contained_type.as_ref().unwrap() } else { ty };
1518
1519                                                 write!(w, "{} {{ ", pfx).unwrap();
1520                                                 let new_var_name = format!("{}_{}", ident, idx);
1521                                                 let new_var = self.write_conversion_new_var_intern(w, &syn::Ident::new(&new_var_name, Span::call_site()),
1522                                                                 &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);
1523                                                 if new_var { write!(w, " ").unwrap(); }
1524                                                 if (!only_contained_has_inner || !to_c) && !contains_slice {
1525                                                         var_prefix(w, conv_ty, generics, is_ref && ty_has_inner, ptr_for_ref, false);
1526                                                 }
1527
1528                                                 if !is_ref && !needs_ref_map && to_c && only_contained_has_inner {
1529                                                         write!(w, "Box::into_raw(Box::new(").unwrap();
1530                                                 }
1531                                                 write!(w, "{}{}", if contains_slice { "local_" } else { "" }, if new_var { new_var_name } else { var_access }).unwrap();
1532                                                 if (!only_contained_has_inner || !to_c) && !contains_slice {
1533                                                         var_suffix(w, conv_ty, generics, is_ref && ty_has_inner, ptr_for_ref, false);
1534                                                 }
1535                                                 if !is_ref && !needs_ref_map && to_c && only_contained_has_inner {
1536                                                         write!(w, "))").unwrap();
1537                                                 }
1538                                                 write!(w, " }}").unwrap();
1539                                         }
1540                                         write!(w, "{}", suffix).unwrap();
1541                                         if only_contained_has_inner && to_c {
1542                                                 var_suffix(w, $args_iter().next().unwrap(), generics, is_ref, ptr_for_ref, true);
1543                                         }
1544                                         write!(w, ";").unwrap();
1545                                         if !to_c && needs_ref_map {
1546                                                 write!(w, " let mut local_{} = local_{}_base.as_ref()", ident, ident).unwrap();
1547                                                 if contains_slice {
1548                                                         write!(w, ".map(|a| &a[..])").unwrap();
1549                                                 }
1550                                                 write!(w, ";").unwrap();
1551                                         }
1552                                         return true;
1553                                 }
1554                         } }
1555                 }
1556
1557                 match t {
1558                         syn::Type::Reference(r) => {
1559                                 if let syn::Type::Slice(_) = &*r.elem {
1560                                         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)
1561                                 } else {
1562                                         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)
1563                                 }
1564                         },
1565                         syn::Type::Path(p) => {
1566                                 if p.qself.is_some() {
1567                                         unimplemented!();
1568                                 }
1569                                 let resolved_path = self.resolve_path(&p.path, generics);
1570                                 if let Some(aliased_type) = self.crate_types.type_aliases.get(&resolved_path) {
1571                                         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);
1572                                 }
1573                                 if self.is_known_container(&resolved_path, is_ref) || self.is_transparent_container(&resolved_path, is_ref) {
1574                                         if let syn::PathArguments::AngleBracketed(args) = &p.path.segments.iter().next().unwrap().arguments {
1575                                                 convert_container!(resolved_path, args.args.len(), || args.args.iter().map(|arg| {
1576                                                         if let syn::GenericArgument::Type(ty) = arg {
1577                                                                 ty
1578                                                         } else { unimplemented!(); }
1579                                                 }));
1580                                         } else { unimplemented!(); }
1581                                 }
1582                                 if self.is_primitive(&resolved_path) {
1583                                         false
1584                                 } else if let Some(ty_ident) = single_ident_generic_path_to_ident(&p.path) {
1585                                         if let Some((prefix, suffix)) = path_lookup(&resolved_path, is_ref) {
1586                                                 write!(w, "let mut local_{} = {}{}{};", ident, prefix, var, suffix).unwrap();
1587                                                 true
1588                                         } else if self.declared.get(ty_ident).is_some() {
1589                                                 false
1590                                         } else { false }
1591                                 } else { false }
1592                         },
1593                         syn::Type::Array(_) => {
1594                                 // We assume all arrays contain only primitive types.
1595                                 // This may result in some outputs not compiling.
1596                                 false
1597                         },
1598                         syn::Type::Slice(s) => {
1599                                 if let syn::Type::Path(p) = &*s.elem {
1600                                         let resolved = self.resolve_path(&p.path, generics);
1601                                         assert!(self.is_primitive(&resolved));
1602                                         let slice_path = format!("[{}]", resolved);
1603                                         if let Some((prefix, suffix)) = path_lookup(&slice_path, true) {
1604                                                 write!(w, "let mut local_{} = {}{}{};", ident, prefix, var, suffix).unwrap();
1605                                                 true
1606                                         } else { false }
1607                                 } else if let syn::Type::Reference(ty) = &*s.elem {
1608                                         let tyref = [&*ty.elem];
1609                                         is_ref = true;
1610                                         convert_container!("Slice", 1, || tyref.iter());
1611                                         unimplemented!("convert_container should return true as container_lookup should succeed for slices");
1612                                 } else if let syn::Type::Tuple(t) = &*s.elem {
1613                                         // When mapping into a temporary new var, we need to own all the underlying objects.
1614                                         // Thus, we drop any references inside the tuple and convert with non-reference types.
1615                                         let mut elems = syn::punctuated::Punctuated::new();
1616                                         for elem in t.elems.iter() {
1617                                                 if let syn::Type::Reference(r) = elem {
1618                                                         elems.push((*r.elem).clone());
1619                                                 } else {
1620                                                         elems.push(elem.clone());
1621                                                 }
1622                                         }
1623                                         let ty = [syn::Type::Tuple(syn::TypeTuple {
1624                                                 paren_token: t.paren_token, elems
1625                                         })];
1626                                         is_ref = false;
1627                                         ptr_for_ref = true;
1628                                         convert_container!("Slice", 1, || ty.iter());
1629                                         unimplemented!("convert_container should return true as container_lookup should succeed for slices");
1630                                 } else { unimplemented!() }
1631                         },
1632                         syn::Type::Tuple(t) => {
1633                                 if !t.elems.is_empty() {
1634                                         // We don't (yet) support tuple elements which cannot be converted inline
1635                                         write!(w, "let (").unwrap();
1636                                         for idx in 0..t.elems.len() {
1637                                                 if idx != 0 { write!(w, ", ").unwrap(); }
1638                                                 write!(w, "{} orig_{}_{}", if is_ref { "ref" } else { "mut" }, ident, idx).unwrap();
1639                                         }
1640                                         write!(w, ") = {}{}; ", var, if !to_c { ".to_rust()" } else { "" }).unwrap();
1641                                         // Like other template types, tuples are always mapped as their non-ref
1642                                         // versions for types which have different ref mappings. Thus, we convert to
1643                                         // non-ref versions and handle opaque types with inner pointers manually.
1644                                         for (idx, elem) in t.elems.iter().enumerate() {
1645                                                 if let syn::Type::Path(p) = elem {
1646                                                         let v_name = format!("orig_{}_{}", ident, idx);
1647                                                         let tuple_elem_ident = syn::Ident::new(&v_name, Span::call_site());
1648                                                         if self.write_conversion_new_var_intern(w, &tuple_elem_ident, &v_name, elem, generics,
1649                                                                         false, ptr_for_ref, to_c,
1650                                                                         path_lookup, container_lookup, var_prefix, var_suffix) {
1651                                                                 write!(w, " ").unwrap();
1652                                                                 // Opaque types with inner pointers shouldn't ever create new stack
1653                                                                 // variables, so we don't handle it and just assert that it doesn't
1654                                                                 // here.
1655                                                                 assert!(!self.c_type_has_inner_from_path(&self.resolve_path(&p.path, generics)));
1656                                                         }
1657                                                 }
1658                                         }
1659                                         write!(w, "let mut local_{} = (", ident).unwrap();
1660                                         for (idx, elem) in t.elems.iter().enumerate() {
1661                                                 let ty_has_inner = {
1662                                                                 if to_c {
1663                                                                         // "To C ptr_for_ref" means "return the regular object with
1664                                                                         // is_owned set to false", which is totally what we want
1665                                                                         // if we're about to set ty_has_inner.
1666                                                                         ptr_for_ref = true;
1667                                                                 }
1668                                                                 if let syn::Type::Reference(t) = elem {
1669                                                                         if let syn::Type::Path(p) = &*t.elem {
1670                                                                                 self.c_type_has_inner_from_path(&self.resolve_path(&p.path, generics))
1671                                                                         } else { false }
1672                                                                 } else if let syn::Type::Path(p) = elem {
1673                                                                         self.c_type_has_inner_from_path(&self.resolve_path(&p.path, generics))
1674                                                                 } else { false }
1675                                                         };
1676                                                 if idx != 0 { write!(w, ", ").unwrap(); }
1677                                                 var_prefix(w, elem, generics, is_ref && ty_has_inner, ptr_for_ref, false);
1678                                                 if is_ref && ty_has_inner {
1679                                                         // For ty_has_inner, the regular var_prefix mapping will take a
1680                                                         // reference, so deref once here to make sure we keep the original ref.
1681                                                         write!(w, "*").unwrap();
1682                                                 }
1683                                                 write!(w, "orig_{}_{}", ident, idx).unwrap();
1684                                                 if is_ref && !ty_has_inner {
1685                                                         // If we don't have an inner variable's reference to maintain, just
1686                                                         // hope the type is Clonable and use that.
1687                                                         write!(w, ".clone()").unwrap();
1688                                                 }
1689                                                 var_suffix(w, elem, generics, is_ref && ty_has_inner, ptr_for_ref, false);
1690                                         }
1691                                         write!(w, "){};", if to_c { ".into()" } else { "" }).unwrap();
1692                                         true
1693                                 } else { false }
1694                         },
1695                         _ => unimplemented!(),
1696                 }
1697         }
1698
1699         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 {
1700                 self.write_conversion_new_var_intern(w, ident, var_access, t, generics, false, ptr_for_ref, true,
1701                         &|a, b| self.to_c_conversion_new_var_from_path(a, b),
1702                         &|a, b, c, d, e| self.to_c_conversion_container_new_var(generics, a, b, c, d, e),
1703                         // We force ptr_for_ref here since we can't generate a ref on one line and use it later
1704                         &|a, b, c, d, e, f| self.write_to_c_conversion_inline_prefix_inner(a, b, c, d, e, f),
1705                         &|a, b, c, d, e, f| self.write_to_c_conversion_inline_suffix_inner(a, b, c, d, e, f))
1706         }
1707         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 {
1708                 self.write_to_c_conversion_new_var_inner(w, ident, &format!("{}", ident), t, generics, ptr_for_ref)
1709         }
1710         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 {
1711                 self.write_conversion_new_var_intern(w, ident, &format!("{}", ident), t, generics, false, false, false,
1712                         &|a, b| self.from_c_conversion_new_var_from_path(a, b),
1713                         &|a, b, c, d, e| self.from_c_conversion_container_new_var(generics, a, b, c, d, e),
1714                         // We force ptr_for_ref here since we can't generate a ref on one line and use it later
1715                         &|a, b, c, d, e, _f| self.write_from_c_conversion_prefix_inner(a, b, c, d, e),
1716                         &|a, b, c, d, e, _f| self.write_from_c_conversion_suffix_inner(a, b, c, d, e))
1717         }
1718
1719         // ******************************************************
1720         // *** C Container Type Equivalent and alias Printing ***
1721         // ******************************************************
1722
1723         fn write_template_constructor<W: std::io::Write>(&mut self, w: &mut W, container_type: &str, mangled_container: &str, args: &Vec<&syn::Type>, generics: Option<&GenericTypes>, is_ref: bool) -> bool {
1724                 if container_type == "Result" {
1725                         assert_eq!(args.len(), 2);
1726                         macro_rules! write_fn {
1727                                 ($call: expr) => { {
1728                                         writeln!(w, "#[no_mangle]\npub extern \"C\" fn {}_{}() -> {} {{", mangled_container, $call, mangled_container).unwrap();
1729                                         writeln!(w, "\t{}::CResultTempl::{}(0)\n}}\n", Self::container_templ_path(), $call).unwrap();
1730                                 } }
1731                         }
1732                         macro_rules! write_alias {
1733                                 ($call: expr, $item: expr) => { {
1734                                         write!(w, "#[no_mangle]\npub static {}_{}: extern \"C\" fn (", mangled_container, $call).unwrap();
1735                                         if let syn::Type::Path(syn::TypePath { path, .. }) = $item {
1736                                                 let resolved = self.resolve_path(path, generics);
1737                                                 if self.is_known_container(&resolved, is_ref) || self.is_transparent_container(&resolved, is_ref) {
1738                                                         self.write_c_mangled_container_path_intern(w, Self::path_to_generic_args(path), generics,
1739                                                                 &format!("{}", single_ident_generic_path_to_ident(path).unwrap()), is_ref, false, false, false);
1740                                                 } else {
1741                                                         self.write_template_generics(w, &mut [$item].iter().map(|t| *t), generics, is_ref, true);
1742                                                 }
1743                                         } else if let syn::Type::Tuple(syn::TypeTuple { elems, .. }) = $item {
1744                                                 self.write_c_mangled_container_path_intern(w, elems.iter().collect(), generics,
1745                                                         &format!("{}Tuple", elems.len()), is_ref, false, false, false);
1746                                         } else { unimplemented!(); }
1747                                         write!(w, ") -> {} =\n\t{}::CResultTempl::<", mangled_container, Self::container_templ_path()).unwrap();
1748                                         self.write_template_generics(w, &mut args.iter().map(|t| *t), generics, is_ref, true);
1749                                         writeln!(w, ">::{};\n", $call).unwrap();
1750                                 } }
1751                         }
1752                         match args[0] {
1753                                 syn::Type::Tuple(t) if t.elems.is_empty() => write_fn!("ok"),
1754                                 _ => write_alias!("ok", args[0]),
1755                         }
1756                         match args[1] {
1757                                 syn::Type::Tuple(t) if t.elems.is_empty() => write_fn!("err"),
1758                                 _ => write_alias!("err", args[1]),
1759                         }
1760                 } else if container_type.ends_with("Tuple") {
1761                         write!(w, "#[no_mangle]\npub extern \"C\" fn {}_new(", mangled_container).unwrap();
1762                         for (idx, gen) in args.iter().enumerate() {
1763                                 write!(w, "{}{}: ", if idx != 0 { ", " } else { "" }, ('a' as u8 + idx as u8) as char).unwrap();
1764                                 if !self.write_c_type_intern(w, gen, None, false, false, false) { return false; }
1765                         }
1766                         writeln!(w, ") -> {} {{", mangled_container).unwrap();
1767                         write!(w, "\t{} {{ ", mangled_container).unwrap();
1768                         for idx in 0..args.len() {
1769                                 write!(w, "{}, ", ('a' as u8 + idx as u8) as char).unwrap();
1770                         }
1771                         writeln!(w, "}}\n}}\n").unwrap();
1772                 } else {
1773                         writeln!(w, "").unwrap();
1774                 }
1775                 true
1776         }
1777
1778         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, in_crate: bool) {
1779                 for (idx, t) in args.enumerate() {
1780                         if idx != 0 {
1781                                 write!(w, ", ").unwrap();
1782                         }
1783                         if let syn::Type::Tuple(tup) = t {
1784                                 if tup.elems.is_empty() {
1785                                         write!(w, "u8").unwrap();
1786                                 } else {
1787                                         write!(w, "{}::C{}TupleTempl<", Self::container_templ_path(), tup.elems.len()).unwrap();
1788                                         self.write_template_generics(w, &mut tup.elems.iter(), generics, is_ref, in_crate);
1789                                         write!(w, ">").unwrap();
1790                                 }
1791                         } else if let syn::Type::Path(p_arg) = t {
1792                                 let resolved_generic = self.resolve_path(&p_arg.path, generics);
1793                                 if self.is_primitive(&resolved_generic) {
1794                                         write!(w, "{}", resolved_generic).unwrap();
1795                                 } else if let Some(c_type) = self.c_type_from_path(&resolved_generic, is_ref, false) {
1796                                         if self.is_known_container(&resolved_generic, is_ref) {
1797                                                         write!(w, "{}::C{}Templ<", Self::container_templ_path(), single_ident_generic_path_to_ident(&p_arg.path).unwrap()).unwrap();
1798                                                 assert_eq!(p_arg.path.segments.len(), 1);
1799                                                 if let syn::PathArguments::AngleBracketed(args) = &p_arg.path.segments.iter().next().unwrap().arguments {
1800                                                         self.write_template_generics(w, &mut args.args.iter().map(|gen|
1801                                                                 if let syn::GenericArgument::Type(t) = gen { t } else { unimplemented!() }),
1802                                                                 generics, is_ref, in_crate);
1803                                                 } else { unimplemented!(); }
1804                                                 write!(w, ">").unwrap();
1805                                         } else if resolved_generic == "Option" {
1806                                                 if let syn::PathArguments::AngleBracketed(args) = &p_arg.path.segments.iter().next().unwrap().arguments {
1807                                                         self.write_template_generics(w, &mut args.args.iter().map(|gen|
1808                                                                 if let syn::GenericArgument::Type(t) = gen { t } else { unimplemented!() }),
1809                                                                 generics, is_ref, in_crate);
1810                                                 } else { unimplemented!(); }
1811                                         } else if in_crate {
1812                                                 write!(w, "{}", c_type).unwrap();
1813                                         } else {
1814                                                 self.write_rust_type(w, generics, &t);
1815                                         }
1816                                 } else {
1817                                         // If we just write out resolved_generic, it may mostly work, however for
1818                                         // original types which are generic, we need the template args. We could
1819                                         // figure them out and write them out, too, but its much easier to just
1820                                         // reference the native{} type alias which exists at least for opaque types.
1821                                         if in_crate {
1822                                                 write!(w, "crate::{}", resolved_generic).unwrap();
1823                                         } else {
1824                                                 let path_name: Vec<&str> = resolved_generic.rsplitn(2, "::").collect();
1825                                                 if path_name.len() > 1 {
1826                                                         write!(w, "crate::{}::native{}", path_name[1], path_name[0]).unwrap();
1827                                                 } else {
1828                                                         write!(w, "crate::native{}", path_name[0]).unwrap();
1829                                                 }
1830                                         }
1831                                 }
1832                         } else if let syn::Type::Reference(r_arg) = t {
1833                                 if let syn::Type::Path(p_arg) = &*r_arg.elem {
1834                                         let resolved = self.resolve_path(&p_arg.path, generics);
1835                                         if self.crate_types.opaques.get(&resolved).is_some() {
1836                                                 write!(w, "crate::{}", resolved).unwrap();
1837                                         } else {
1838                                                 let cty = self.c_type_from_path(&resolved, true, true).expect("Template generics should be opaque or have a predefined mapping");
1839                                                 w.write(cty.as_bytes()).unwrap();
1840                                         }
1841                                 } else { unimplemented!(); }
1842                         } else if let syn::Type::Array(a_arg) = t {
1843                                 if let syn::Type::Path(p_arg) = &*a_arg.elem {
1844                                         let resolved = self.resolve_path(&p_arg.path, generics);
1845                                         assert!(self.is_primitive(&resolved));
1846                                         if let syn::Expr::Lit(syn::ExprLit { lit: syn::Lit::Int(len), .. }) = &a_arg.len {
1847                                                 write!(w, "{}",
1848                                                         self.c_type_from_path(&format!("[{}; {}]", resolved, len.base10_digits()), is_ref, false).unwrap()).unwrap();
1849                                         }
1850                                 }
1851                         }
1852                 }
1853         }
1854         fn check_create_container(&mut self, mangled_container: String, container_type: &str, args: Vec<&syn::Type>, generics: Option<&GenericTypes>, is_ref: bool) -> bool {
1855                 if !self.crate_types.templates_defined.get(&mangled_container).is_some() {
1856                         let mut created_container: Vec<u8> = Vec::new();
1857
1858                         write!(&mut created_container, "pub type {} = ", mangled_container).unwrap();
1859                         write!(&mut created_container, "{}::C{}Templ<", Self::container_templ_path(), container_type).unwrap();
1860                         self.write_template_generics(&mut created_container, &mut args.iter().map(|t| *t), generics, is_ref, true);
1861                         writeln!(&mut created_container, ">;").unwrap();
1862
1863                         write!(&mut created_container, "#[no_mangle]\npub static {}_free: extern \"C\" fn({}) = ", mangled_container, mangled_container).unwrap();
1864                         write!(&mut created_container, "{}::C{}Templ_free::<", Self::container_templ_path(), container_type).unwrap();
1865                         self.write_template_generics(&mut created_container, &mut args.iter().map(|t| *t), generics, is_ref, true);
1866                         writeln!(&mut created_container, ">;").unwrap();
1867
1868                         if !self.write_template_constructor(&mut created_container, container_type, &mangled_container, &args, generics, is_ref) {
1869                                 return false;
1870                         }
1871                         self.crate_types.templates_defined.insert(mangled_container.clone(), true);
1872
1873                         self.crate_types.template_file.write(&created_container).unwrap();
1874                 }
1875                 true
1876         }
1877         fn path_to_generic_args(path: &syn::Path) -> Vec<&syn::Type> {
1878                 if let syn::PathArguments::AngleBracketed(args) = &path.segments.iter().next().unwrap().arguments {
1879                         args.args.iter().map(|gen| if let syn::GenericArgument::Type(t) = gen { t } else { unimplemented!() }).collect()
1880                 } else { unimplemented!(); }
1881         }
1882         fn write_c_mangled_container_path_intern<W: std::io::Write>
1883                         (&mut 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 {
1884                 let mut mangled_type: Vec<u8> = Vec::new();
1885                 if !self.is_transparent_container(ident, is_ref) {
1886                         write!(w, "C{}_", ident).unwrap();
1887                         write!(mangled_type, "C{}_", ident).unwrap();
1888                 } else { assert_eq!(args.len(), 1); }
1889                 for arg in args.iter() {
1890                         macro_rules! write_path {
1891                                 ($p_arg: expr, $extra_write: expr) => {
1892                                         if let Some(subtype) = self.maybe_resolve_path(&$p_arg.path, generics) {
1893                                                 if self.is_transparent_container(ident, is_ref) {
1894                                                         // We dont (yet) support primitives or containers inside transparent
1895                                                         // containers, so check for that first:
1896                                                         if self.is_primitive(&subtype) { return false; }
1897                                                         if self.is_known_container(&subtype, is_ref) { return false; }
1898                                                         if !in_type {
1899                                                                 if self.c_type_has_inner_from_path(&subtype) {
1900                                                                         if !self.write_c_path_intern(w, &$p_arg.path, generics, is_ref, is_mut, ptr_for_ref) { return false; }
1901                                                                 } else {
1902                                                                         // Option<T> needs to be converted to a *mut T, ie mut ptr-for-ref
1903                                                                         if !self.write_c_path_intern(w, &$p_arg.path, generics, true, true, true) { return false; }
1904                                                                 }
1905                                                         } else {
1906                                                                 if $p_arg.path.segments.len() == 1 {
1907                                                                         write!(w, "{}", $p_arg.path.segments.iter().next().unwrap().ident).unwrap();
1908                                                                 } else {
1909                                                                         return false;
1910                                                                 }
1911                                                         }
1912                                                 } else if self.is_known_container(&subtype, is_ref) || self.is_transparent_container(&subtype, is_ref) {
1913                                                         if !self.write_c_mangled_container_path_intern(w, Self::path_to_generic_args(&$p_arg.path), generics,
1914                                                                         &subtype, is_ref, is_mut, ptr_for_ref, true) {
1915                                                                 return false;
1916                                                         }
1917                                                         self.write_c_mangled_container_path_intern(&mut mangled_type, Self::path_to_generic_args(&$p_arg.path),
1918                                                                 generics, &subtype, is_ref, is_mut, ptr_for_ref, true);
1919                                                         if let Some(w2) = $extra_write as Option<&mut Vec<u8>> {
1920                                                                 self.write_c_mangled_container_path_intern(w2, Self::path_to_generic_args(&$p_arg.path),
1921                                                                         generics, &subtype, is_ref, is_mut, ptr_for_ref, true);
1922                                                         }
1923                                                 } else {
1924                                                         let id = &&$p_arg.path.segments.iter().rev().next().unwrap().ident;
1925                                                         write!(w, "{}", id).unwrap();
1926                                                         write!(mangled_type, "{}", id).unwrap();
1927                                                         if let Some(w2) = $extra_write as Option<&mut Vec<u8>> {
1928                                                                 write!(w2, "{}", id).unwrap();
1929                                                         }
1930                                                 }
1931                                         } else { return false; }
1932                                 }
1933                         }
1934                         if let syn::Type::Tuple(tuple) = arg {
1935                                 if tuple.elems.len() == 0 {
1936                                         write!(w, "None").unwrap();
1937                                         write!(mangled_type, "None").unwrap();
1938                                 } else {
1939                                         let mut mangled_tuple_type: Vec<u8> = Vec::new();
1940
1941                                         // Figure out what the mangled type should look like. To disambiguate
1942                                         // ((A, B), C) and (A, B, C) we prefix the generic args with a _ and suffix
1943                                         // them with a Z. Ideally we wouldn't use Z, but not many special chars are
1944                                         // available for use in type names.
1945                                         write!(w, "C{}Tuple_", tuple.elems.len()).unwrap();
1946                                         write!(mangled_type, "C{}Tuple_", tuple.elems.len()).unwrap();
1947                                         write!(mangled_tuple_type, "C{}Tuple_", tuple.elems.len()).unwrap();
1948                                         for elem in tuple.elems.iter() {
1949                                                 if let syn::Type::Path(p) = elem {
1950                                                         write_path!(p, Some(&mut mangled_tuple_type));
1951                                                 } else if let syn::Type::Reference(refelem) = elem {
1952                                                         if let syn::Type::Path(p) = &*refelem.elem {
1953                                                                 write_path!(p, Some(&mut mangled_tuple_type));
1954                                                         } else { return false; }
1955                                                 } else { return false; }
1956                                         }
1957                                         write!(w, "Z").unwrap();
1958                                         write!(mangled_type, "Z").unwrap();
1959                                         write!(mangled_tuple_type, "Z").unwrap();
1960                                         if !self.check_create_container(String::from_utf8(mangled_tuple_type).unwrap(),
1961                                                         &format!("{}Tuple", tuple.elems.len()), tuple.elems.iter().collect(), generics, is_ref) {
1962                                                 return false;
1963                                         }
1964                                 }
1965                         } else if let syn::Type::Path(p_arg) = arg {
1966                                 write_path!(p_arg, None);
1967                         } else if let syn::Type::Reference(refty) = arg {
1968                                 if args.len() != 1 { return false; }
1969                                 if let syn::Type::Path(p_arg) = &*refty.elem {
1970                                         write_path!(p_arg, None);
1971                                 } else if let syn::Type::Slice(_) = &*refty.elem {
1972                                         // write_c_type will actually do exactly what we want here, we just need to
1973                                         // make it a pointer so that its an option. Note that we cannot always convert
1974                                         // the Vec-as-slice (ie non-ref types) containers, so sometimes need to be able
1975                                         // to edit it, hence we use *mut here instead of *const.
1976                                         write!(w, "*mut ").unwrap();
1977                                         self.write_c_type(w, arg, None, true);
1978                                 } else { return false; }
1979                         } else if let syn::Type::Array(a) = arg {
1980                                 if let syn::Type::Path(p_arg) = &*a.elem {
1981                                         let resolved = self.resolve_path(&p_arg.path, generics);
1982                                         if !self.is_primitive(&resolved) { return false; }
1983                                         if let syn::Expr::Lit(syn::ExprLit { lit: syn::Lit::Int(len), .. }) = &a.len {
1984                                                 if self.c_type_from_path(&format!("[{}; {}]", resolved, len.base10_digits()), is_ref, ptr_for_ref).is_none() { return false; }
1985                                                 write!(w, "_{}{}", resolved, len.base10_digits()).unwrap();
1986                                                 write!(mangled_type, "_{}{}", resolved, len.base10_digits()).unwrap();
1987                                         } else { return false; }
1988                                 } else { return false; }
1989                         } else { return false; }
1990                 }
1991                 if self.is_transparent_container(ident, is_ref) { return true; }
1992                 // Push the "end of type" Z
1993                 write!(w, "Z").unwrap();
1994                 write!(mangled_type, "Z").unwrap();
1995
1996                 // Make sure the type is actually defined:
1997                 self.check_create_container(String::from_utf8(mangled_type).unwrap(), ident, args, generics, is_ref)
1998         }
1999         fn write_c_mangled_container_path<W: std::io::Write>(&mut self, w: &mut W, args: Vec<&syn::Type>, generics: Option<&GenericTypes>, ident: &str, is_ref: bool, is_mut: bool, ptr_for_ref: bool) -> bool {
2000                 if !self.is_transparent_container(ident, is_ref) {
2001                         write!(w, "{}::", Self::generated_container_path()).unwrap();
2002                 }
2003                 self.write_c_mangled_container_path_intern(w, args, generics, ident, is_ref, is_mut, ptr_for_ref, false)
2004         }
2005
2006         // **********************************
2007         // *** C Type Equivalent Printing ***
2008         // **********************************
2009
2010         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 {
2011                 let full_path = match self.maybe_resolve_path(&path, generics) {
2012                         Some(path) => path, None => return false };
2013                 if let Some(c_type) = self.c_type_from_path(&full_path, is_ref, ptr_for_ref) {
2014                         write!(w, "{}", c_type).unwrap();
2015                         true
2016                 } else if self.crate_types.traits.get(&full_path).is_some() {
2017                         if is_ref && ptr_for_ref {
2018                                 write!(w, "*{} crate::{}", if is_mut { "mut" } else { "const" }, full_path).unwrap();
2019                         } else if is_ref {
2020                                 write!(w, "&{}crate::{}", if is_mut { "mut " } else { "" }, full_path).unwrap();
2021                         } else {
2022                                 write!(w, "crate::{}", full_path).unwrap();
2023                         }
2024                         true
2025                 } else if self.crate_types.opaques.get(&full_path).is_some() || self.crate_types.mirrored_enums.get(&full_path).is_some() {
2026                         if is_ref && ptr_for_ref {
2027                                 // ptr_for_ref implies we're returning the object, which we can't really do for
2028                                 // opaque or mirrored types without box'ing them, which is quite a waste, so return
2029                                 // the actual object itself (for opaque types we'll set the pointer to the actual
2030                                 // type and note that its a reference).
2031                                 write!(w, "crate::{}", full_path).unwrap();
2032                         } else if is_ref {
2033                                 write!(w, "&{}crate::{}", if is_mut { "mut " } else { "" }, full_path).unwrap();
2034                         } else {
2035                                 write!(w, "crate::{}", full_path).unwrap();
2036                         }
2037                         true
2038                 } else {
2039                         false
2040                 }
2041         }
2042         fn write_c_type_intern<W: std::io::Write>(&mut self, w: &mut W, t: &syn::Type, generics: Option<&GenericTypes>, is_ref: bool, is_mut: bool, ptr_for_ref: bool) -> bool {
2043                 match t {
2044                         syn::Type::Path(p) => {
2045                                 if p.qself.is_some() {
2046                                         return false;
2047                                 }
2048                                 if let Some(full_path) = self.maybe_resolve_path(&p.path, generics) {
2049                                         if self.is_known_container(&full_path, is_ref) || self.is_transparent_container(&full_path, is_ref) {
2050                                                 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);
2051                                         }
2052                                         if let Some(aliased_type) = self.crate_types.type_aliases.get(&full_path).cloned() {
2053                                                 return self.write_c_type_intern(w, &aliased_type, None, is_ref, is_mut, ptr_for_ref);
2054                                         }
2055                                 }
2056                                 self.write_c_path_intern(w, &p.path, generics, is_ref, is_mut, ptr_for_ref)
2057                         },
2058                         syn::Type::Reference(r) => {
2059                                 self.write_c_type_intern(w, &*r.elem, generics, true, r.mutability.is_some(), ptr_for_ref)
2060                         },
2061                         syn::Type::Array(a) => {
2062                                 if is_ref && is_mut {
2063                                         write!(w, "*mut [").unwrap();
2064                                         if !self.write_c_type_intern(w, &a.elem, generics, false, false, ptr_for_ref) { return false; }
2065                                 } else if is_ref {
2066                                         write!(w, "*const [").unwrap();
2067                                         if !self.write_c_type_intern(w, &a.elem, generics, false, false, ptr_for_ref) { return false; }
2068                                 } else {
2069                                         let mut typecheck = Vec::new();
2070                                         if !self.write_c_type_intern(&mut typecheck, &a.elem, generics, false, false, ptr_for_ref) { return false; }
2071                                         if typecheck[..] != ['u' as u8, '8' as u8] { return false; }
2072                                 }
2073                                 if let syn::Expr::Lit(l) = &a.len {
2074                                         if let syn::Lit::Int(i) = &l.lit {
2075                                                 if !is_ref {
2076                                                         if let Some(ty) = self.c_type_from_path(&format!("[u8; {}]", i.base10_digits()), false, ptr_for_ref) {
2077                                                                 write!(w, "{}", ty).unwrap();
2078                                                                 true
2079                                                         } else { false }
2080                                                 } else {
2081                                                         write!(w, "; {}]", i).unwrap();
2082                                                         true
2083                                                 }
2084                                         } else { false }
2085                                 } else { false }
2086                         }
2087                         syn::Type::Slice(s) => {
2088                                 if !is_ref || is_mut { return false; }
2089                                 if let syn::Type::Path(p) = &*s.elem {
2090                                         let resolved = self.resolve_path(&p.path, generics);
2091                                         if self.is_primitive(&resolved) {
2092                                                 write!(w, "{}::{}slice", Self::container_templ_path(), resolved).unwrap();
2093                                                 true
2094                                         } else { false }
2095                                 } else if let syn::Type::Reference(r) = &*s.elem {
2096                                         if let syn::Type::Path(p) = &*r.elem {
2097                                                 // Slices with "real types" inside are mapped as the equivalent non-ref Vec
2098                                                 let resolved = self.resolve_path(&p.path, generics);
2099                                                 let mangled_container = if let Some(ident) = self.crate_types.opaques.get(&resolved) {
2100                                                         format!("CVec_{}Z", ident)
2101                                                 } else if let Some(en) = self.crate_types.mirrored_enums.get(&resolved) {
2102                                                         format!("CVec_{}Z", en.ident)
2103                                                 } else if let Some(id) = p.path.get_ident() {
2104                                                         format!("CVec_{}Z", id)
2105                                                 } else { return false; };
2106                                                 write!(w, "{}::{}", Self::generated_container_path(), mangled_container).unwrap();
2107                                                 self.check_create_container(mangled_container, "Vec", vec![&*r.elem], generics, false)
2108                                         } else { false }
2109                                 } else if let syn::Type::Tuple(_) = &*s.elem {
2110                                         let mut args = syn::punctuated::Punctuated::new();
2111                                         args.push(syn::GenericArgument::Type((*s.elem).clone()));
2112                                         let mut segments = syn::punctuated::Punctuated::new();
2113                                         segments.push(syn::PathSegment {
2114                                                 ident: syn::Ident::new("Vec", Span::call_site()),
2115                                                 arguments: syn::PathArguments::AngleBracketed(syn::AngleBracketedGenericArguments {
2116                                                         colon2_token: None, lt_token: syn::Token![<](Span::call_site()), args, gt_token: syn::Token![>](Span::call_site()),
2117                                                 })
2118                                         });
2119                                         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)
2120                                 } else { false }
2121                         },
2122                         syn::Type::Tuple(t) => {
2123                                 if t.elems.len() == 0 {
2124                                         true
2125                                 } else {
2126                                         self.write_c_mangled_container_path(w, t.elems.iter().collect(), generics,
2127                                                 &format!("{}Tuple", t.elems.len()), is_ref, is_mut, ptr_for_ref)
2128                                 }
2129                         },
2130                         _ => false,
2131                 }
2132         }
2133         pub fn write_c_type<W: std::io::Write>(&mut self, w: &mut W, t: &syn::Type, generics: Option<&GenericTypes>, ptr_for_ref: bool) {
2134                 assert!(self.write_c_type_intern(w, t, generics, false, false, ptr_for_ref));
2135         }
2136         pub fn understood_c_path(&mut self, p: &syn::Path) -> bool {
2137                 if p.leading_colon.is_some() { return false; }
2138                 self.write_c_path_intern(&mut std::io::sink(), p, None, false, false, false)
2139         }
2140         pub fn understood_c_type(&mut self, t: &syn::Type, generics: Option<&GenericTypes>) -> bool {
2141                 self.write_c_type_intern(&mut std::io::sink(), t, generics, false, false, false)
2142         }
2143 }