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

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