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

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