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

   1 // This file is Copyright its original authors, visible in version control
   2 // history.
   3 //
   4 // This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE>
   5 // or the MIT license <LICENSE-MIT>, at your option.
   6 // You may not use this file except in accordance with one or both of these
   7 // licenses.
   8
   9 //! Converts a rust crate into a rust crate containing a number of C-exported wrapper functions and
  10 //! classes (which is exportable using cbindgen).
  11 //! In general, supports convering:
  12 //!  * structs as a pointer to the underlying type (either owned or not owned),
  13 //!  * traits as a void-ptr plus a jump table,
  14 //!  * enums as an equivalent enum with all the inner fields mapped to the mapped types,
  15 //!  * certain containers (tuples, slices, Vecs, Options, and Results currently) to a concrete
  16 //!    version of a defined container template.
  17 //!
  18 //! It also generates relevant memory-management functions and free-standing functions with
  19 //! parameters mapped.
  20
  21 use std::collections::{HashMap, hash_map};
  22 use std::env;
  23 use std::fs::File;
  24 use std::io::{Read, Write};
  25 use std::process;
  26
  27 use proc_macro2::Span;
  28 use quote::format_ident;
  29 use syn::parse_quote;
  30
  31 mod types;
  32 mod blocks;
  33 use types::*;
  34 use blocks::*;
  35
  36 const DEFAULT_IMPORTS: &'static str = "\nuse std::str::FromStr;\nuse std::ffi::c_void;\nuse bitcoin::hashes::Hash;\nuse crate::c_types::*;\n";
  37
  38 // *************************************
  39 // *** Manually-expanded conversions ***
  40 // *************************************
  41
  42 /// Convert "impl trait_path for for_ty { .. }" for manually-mapped types (ie (de)serialization)
  43 fn maybe_convert_trait_impl<W: std::io::Write>(w: &mut W, trait_path: &syn::Path, for_ty: &syn::Type, types: &mut TypeResolver, generics: &GenericTypes) {
  44         if let Some(t) = types.maybe_resolve_path(&trait_path, Some(generics)) {
  45                 let for_obj;
  46                 let full_obj_path;
  47                 let mut has_inner = false;
  48                 if let syn::Type::Path(ref p) = for_ty {
  49                         if let Some(ident) = single_ident_generic_path_to_ident(&p.path) {
  50                                 for_obj = format!("{}", ident);
  51                                 full_obj_path = for_obj.clone();
  52                                 has_inner = types.c_type_has_inner_from_path(&types.resolve_path(&p.path, Some(generics)));
  53                         } else { return; }
  54                 } else {
  55                         // We assume that anything that isn't a Path is somehow a generic that ends up in our
  56                         // derived-types module.
  57                         let mut for_obj_vec = Vec::new();
  58                         types.write_c_type(&mut for_obj_vec, for_ty, Some(generics), false);
  59                         full_obj_path = String::from_utf8(for_obj_vec).unwrap();
  60                         assert!(full_obj_path.starts_with(TypeResolver::generated_container_path()));
  61                         for_obj = full_obj_path[TypeResolver::generated_container_path().len() + 2..].into();
  62                 }
  63
  64                 match &t as &str {
  65                         "lightning::util::ser::Writeable" => {
  66                                 writeln!(w, "#[no_mangle]").unwrap();
  67                                 writeln!(w, "/// Serialize the {} object into a byte array which can be read by {}_read", for_obj, for_obj).unwrap();
  68                                 writeln!(w, "pub extern \"C\" fn {}_write(obj: &{}) -> crate::c_types::derived::CVec_u8Z {{", for_obj, full_obj_path).unwrap();
  69
  70                                 let ref_type: syn::Type = syn::parse_quote!(&#for_ty);
  71                                 assert!(!types.write_from_c_conversion_new_var(w, &format_ident!("obj"), &ref_type, Some(generics)));
  72
  73                                 write!(w, "\tcrate::c_types::serialize_obj(").unwrap();
  74                                 types.write_from_c_conversion_prefix(w, &ref_type, Some(generics));
  75                                 write!(w, "unsafe {{ &*obj }}").unwrap();
  76                                 types.write_from_c_conversion_suffix(w, &ref_type, Some(generics));
  77                                 writeln!(w, ")").unwrap();
  78
  79                                 writeln!(w, "}}").unwrap();
  80                                 if has_inner {
  81                                         writeln!(w, "#[no_mangle]").unwrap();
  82                                         writeln!(w, "pub(crate) extern \"C\" fn {}_write_void(obj: *const c_void) -> crate::c_types::derived::CVec_u8Z {{", for_obj).unwrap();
  83                                         writeln!(w, "\tcrate::c_types::serialize_obj(unsafe {{ &*(obj as *const native{}) }})", for_obj).unwrap();
  84                                         writeln!(w, "}}").unwrap();
  85                                 }
  86                         },
  87                         "lightning::util::ser::Readable"|"lightning::util::ser::ReadableArgs" => {
  88                                 // Create the Result<Object, DecodeError> syn::Type
  89                                 let res_ty: syn::Type = parse_quote!(Result<#for_ty, ::ln::msgs::DecodeError>);
  90
  91                                 writeln!(w, "#[no_mangle]").unwrap();
  92                                 writeln!(w, "/// Read a {} from a byte array, created by {}_write", for_obj, for_obj).unwrap();
  93                                 write!(w, "pub extern \"C\" fn {}_read(ser: crate::c_types::u8slice", for_obj).unwrap();
  94
  95                                 let mut arg_conv = Vec::new();
  96                                 if t == "lightning::util::ser::ReadableArgs" {
  97                                         write!(w, ", arg: ").unwrap();
  98                                         assert!(trait_path.leading_colon.is_none());
  99                                         let args_seg = trait_path.segments.iter().last().unwrap();
 100                                         assert_eq!(format!("{}", args_seg.ident), "ReadableArgs");
 101                                         if let syn::PathArguments::AngleBracketed(args) = &args_seg.arguments {
 102                                                 assert_eq!(args.args.len(), 1);
 103                                                 if let syn::GenericArgument::Type(args_ty) = args.args.iter().next().unwrap() {
 104                                                         types.write_c_type(w, args_ty, Some(generics), false);
 105
 106                                                         assert!(!types.write_from_c_conversion_new_var(&mut arg_conv, &format_ident!("arg"), &args_ty, Some(generics)));
 107
 108                                                         write!(&mut arg_conv, "\tlet arg_conv = ").unwrap();
 109                                                         types.write_from_c_conversion_prefix(&mut arg_conv, &args_ty, Some(generics));
 110                                                         write!(&mut arg_conv, "arg").unwrap();
 111                                                         types.write_from_c_conversion_suffix(&mut arg_conv, &args_ty, Some(generics));
 112                                                 } else { unreachable!(); }
 113                                         } else { unreachable!(); }
 114                                 }
 115                                 write!(w, ") -> ").unwrap();
 116                                 types.write_c_type(w, &res_ty, Some(generics), false);
 117                                 writeln!(w, " {{").unwrap();
 118
 119                                 if t == "lightning::util::ser::ReadableArgs" {
 120                                         w.write(&arg_conv).unwrap();
 121                                         write!(w, ";\n\tlet res: ").unwrap();
 122                                         // At least in one case we need type annotations here, so provide them.
 123                                         types.write_rust_type(w, Some(generics), &res_ty);
 124                                         writeln!(w, " = crate::c_types::deserialize_obj_arg(ser, arg_conv);").unwrap();
 125                                 } else {
 126                                         writeln!(w, "\tlet res = crate::c_types::deserialize_obj(ser);").unwrap();
 127                                 }
 128                                 write!(w, "\t").unwrap();
 129                                 if types.write_to_c_conversion_new_var(w, &format_ident!("res"), &res_ty, Some(generics), false) {
 130                                         write!(w, "\n\t").unwrap();
 131                                 }
 132                                 types.write_to_c_conversion_inline_prefix(w, &res_ty, Some(generics), false);
 133                                 write!(w, "res").unwrap();
 134                                 types.write_to_c_conversion_inline_suffix(w, &res_ty, Some(generics), false);
 135                                 writeln!(w, "\n}}").unwrap();
 136                         },
 137                         _ => {},
 138                 }
 139         }
 140 }
 141
 142 /// Convert "TraitA : TraitB" to a single function name and return type.
 143 ///
 144 /// This is (obviously) somewhat over-specialized and only useful for TraitB's that only require a
 145 /// single function (eg for serialization).
 146 fn convert_trait_impl_field(trait_path: &str) -> (&'static str, String, &'static str) {
 147         match trait_path {
 148                 "lightning::util::ser::Writeable" => ("Serialize the object into a byte array", "write".to_owned(), "crate::c_types::derived::CVec_u8Z"),
 149                 _ => unimplemented!(),
 150         }
 151 }
 152
 153 /// Companion to convert_trait_impl_field, write an assignment for the function defined by it for
 154 /// `for_obj` which implements the the trait at `trait_path`.
 155 fn write_trait_impl_field_assign<W: std::io::Write>(w: &mut W, trait_path: &str, for_obj: &syn::Ident) {
 156         match trait_path {
 157                 "lightning::util::ser::Writeable" => {
 158                         writeln!(w, "\t\twrite: {}_write_void,", for_obj).unwrap();
 159                 },
 160                 _ => unimplemented!(),
 161         }
 162 }
 163
 164 /// Write out the impl block for a defined trait struct which has a supertrait
 165 fn do_write_impl_trait<W: std::io::Write>(w: &mut W, trait_path: &str, _trait_name: &syn::Ident, for_obj: &str) {
 166 eprintln!("{}", trait_path);
 167         match trait_path {
 168                 "lightning::util::ser::Writeable" => {
 169                         writeln!(w, "impl {} for {} {{", trait_path, for_obj).unwrap();
 170                         writeln!(w, "\tfn write<W: lightning::util::ser::Writer>(&self, w: &mut W) -> Result<(), ::std::io::Error> {{").unwrap();
 171                         writeln!(w, "\t\tlet vec = (self.write)(self.this_arg);").unwrap();
 172                         writeln!(w, "\t\tw.write_all(vec.as_slice())").unwrap();
 173                         writeln!(w, "\t}}\n}}").unwrap();
 174                 },
 175                 _ => panic!(),
 176         }
 177 }
 178
 179 // *******************************
 180 // *** Per-Type Printing Logic ***
 181 // *******************************
 182
 183 macro_rules! walk_supertraits { ($t: expr, $types: expr, ($( $($pat: pat)|* => $e: expr),*) ) => { {
 184         if $t.colon_token.is_some() {
 185                 for st in $t.supertraits.iter() {
 186                         match st {
 187                                 syn::TypeParamBound::Trait(supertrait) => {
 188                                         if supertrait.paren_token.is_some() || supertrait.lifetimes.is_some() {
 189                                                 unimplemented!();
 190                                         }
 191                                         // First try to resolve path to find in-crate traits, but if that doesn't work
 192                                         // assume its a prelude trait (eg Clone, etc) and just use the single ident.
 193                                         let types_opt: Option<&TypeResolver> = $types;
 194                                         if let Some(types) = types_opt {
 195                                                 if let Some(path) = types.maybe_resolve_path(&supertrait.path, None) {
 196                                                         match (&path as &str, &supertrait.path.segments.iter().last().unwrap().ident) {
 197                                                                 $( $($pat)|* => $e, )*
 198                                                         }
 199                                                         continue;
 200                                                 }
 201                                         }
 202                                         if let Some(ident) = supertrait.path.get_ident() {
 203                                                 match (&format!("{}", ident) as &str, &ident) {
 204                                                         $( $($pat)|* => $e, )*
 205                                                 }
 206                                         } else if types_opt.is_some() {
 207                                                 panic!("Supertrait unresolvable and not single-ident");
 208                                         }
 209                                 },
 210                                 syn::TypeParamBound::Lifetime(_) => unimplemented!(),
 211                         }
 212                 }
 213         }
 214 } } }
 215
 216 /// Prints a C-mapped trait object containing a void pointer and a jump table for each function in
 217 /// the original trait.
 218 /// Implements the native Rust trait and relevant parent traits for the new C-mapped trait.
 219 ///
 220 /// Finally, implements Deref<MappedTrait> for MappedTrait which allows its use in types which need
 221 /// a concrete Deref to the Rust trait.
 222 fn writeln_trait<'a, 'b, W: std::io::Write>(w: &mut W, t: &'a syn::ItemTrait, types: &mut TypeResolver<'b, 'a>, extra_headers: &mut File, cpp_headers: &mut File) {
 223         let trait_name = format!("{}", t.ident);
 224         let implementable;
 225         match export_status(&t.attrs) {
 226                 ExportStatus::Export => { implementable = true; }
 227                 ExportStatus::NotImplementable => { implementable = false; },
 228                 ExportStatus::NoExport|ExportStatus::TestOnly => return,
 229         }
 230         writeln_docs(w, &t.attrs, "");
 231
 232         let mut gen_types = GenericTypes::new(None);
 233         assert!(gen_types.learn_generics(&t.generics, types));
 234         gen_types.learn_associated_types(&t, types);
 235
 236         writeln!(w, "#[repr(C)]\npub struct {} {{", trait_name).unwrap();
 237         writeln!(w, "\t/// An opaque pointer which is passed to your function implementations as an argument.").unwrap();
 238         writeln!(w, "\t/// This has no meaning in the LDK, and can be NULL or any other value.").unwrap();
 239         writeln!(w, "\tpub this_arg: *mut c_void,").unwrap();
 240         // We store every field's (name, Option<clone_fn>, docs) except this_arg, used in Clone generation
 241         // docs is only set if its a function which should be callable on the object itself in C++
 242         let mut generated_fields = Vec::new();
 243         for item in t.items.iter() {
 244                 match item {
 245                         &syn::TraitItem::Method(ref m) => {
 246                                 match export_status(&m.attrs) {
 247                                         ExportStatus::NoExport => {
 248                                                 // NoExport in this context means we'll hit an unimplemented!() at runtime,
 249                                                 // so bail out.
 250                                                 unimplemented!();
 251                                         },
 252                                         ExportStatus::Export => {},
 253                                         ExportStatus::TestOnly => continue,
 254                                         ExportStatus::NotImplementable => panic!("(C-not implementable) must only appear on traits"),
 255                                 }
 256                                 if m.default.is_some() { unimplemented!(); }
 257
 258                                 let mut meth_gen_types = gen_types.push_ctx();
 259                                 assert!(meth_gen_types.learn_generics(&m.sig.generics, types));
 260
 261                                 writeln_fn_docs(w, &m.attrs, "\t", types, Some(&meth_gen_types), m.sig.inputs.iter(), &m.sig.output);
 262
 263                                 if let syn::ReturnType::Type(_, rtype) = &m.sig.output {
 264                                         if let syn::Type::Reference(r) = &**rtype {
 265                                                 // We have to do quite a dance for trait functions which return references
 266                                                 // - they ultimately require us to have a native Rust object stored inside
 267                                                 // our concrete trait to return a reference to. However, users may wish to
 268                                                 // update the value to be returned each time the function is called (or, to
 269                                                 // make C copies of Rust impls equivalent, we have to be able to).
 270                                                 //
 271                                                 // Thus, we store a copy of the C-mapped type (which is just a pointer to
 272                                                 // the Rust type and a flag to indicate whether deallocation needs to
 273                                                 // happen) as well as provide an Option<>al function pointer which is
 274                                                 // called when the trait method is called which allows updating on the fly.
 275                                                 write!(w, "\tpub {}: ", m.sig.ident).unwrap();
 276                                                 generated_fields.push((format!("{}", m.sig.ident), None, None));
 277                                                 types.write_c_type(w, &*r.elem, Some(&meth_gen_types), false);
 278                                                 writeln!(w, ",").unwrap();
 279                                                 writeln!(w, "\t/// Fill in the {} field as a reference to it will be given to Rust after this returns", m.sig.ident).unwrap();
 280                                                 writeln!(w, "\t/// Note that this takes a pointer to this object, not the this_ptr like other methods do").unwrap();
 281                                                 writeln!(w, "\t/// This function pointer may be NULL if {} is filled in when this object is created and never needs updating.", m.sig.ident).unwrap();
 282                                                 writeln!(w, "\tpub set_{}: Option<extern \"C\" fn(&{})>,", m.sig.ident, trait_name).unwrap();
 283                                                 generated_fields.push((format!("set_{}", m.sig.ident), None, None));
 284                                                 // Note that cbindgen will now generate
 285                                                 // typedef struct Thing {..., set_thing: (const struct Thing*), ...} Thing;
 286                                                 // which does not compile since Thing is not defined before it is used.
 287                                                 writeln!(extra_headers, "struct LDK{};", trait_name).unwrap();
 288                                                 continue;
 289                                         }
 290                                         // Sadly, this currently doesn't do what we want, but it should be easy to get
 291                                         // cbindgen to support it. See https://github.com/eqrion/cbindgen/issues/531
 292                                         writeln!(w, "\t#[must_use]").unwrap();
 293                                 }
 294
 295                                 let mut cpp_docs = Vec::new();
 296                                 writeln_fn_docs(&mut cpp_docs, &m.attrs, "\t * ", types, Some(&meth_gen_types), m.sig.inputs.iter(), &m.sig.output);
 297                                 let docs_string = "\t/**\n".to_owned() + &String::from_utf8(cpp_docs).unwrap().replace("///", "") + "\t */\n";
 298
 299                                 write!(w, "\tpub {}: extern \"C\" fn (", m.sig.ident).unwrap();
 300                                 generated_fields.push((format!("{}", m.sig.ident), None, Some(docs_string)));
 301                                 write_method_params(w, &m.sig, "c_void", types, Some(&meth_gen_types), true, false);
 302                                 writeln!(w, ",").unwrap();
 303                         },
 304                         &syn::TraitItem::Type(_) => {},
 305                         _ => unimplemented!(),
 306                 }
 307         }
 308         // Add functions which may be required for supertrait implementations.
 309         walk_supertraits!(t, Some(&types), (
 310                 ("Clone", _) => {
 311                         writeln!(w, "\t/// Called, if set, after this {} has been cloned into a duplicate object.", trait_name).unwrap();
 312                         writeln!(w, "\t/// The new {} is provided, and should be mutated as needed to perform a", trait_name).unwrap();
 313                         writeln!(w, "\t/// deep copy of the object pointed to by this_arg or avoid any double-freeing.").unwrap();
 314                         writeln!(w, "\tpub cloned: Option<extern \"C\" fn (new_{}: &mut {})>,", trait_name, trait_name).unwrap();
 315                         generated_fields.push(("cloned".to_owned(), None, None));
 316                 },
 317                 ("std::cmp::Eq", _)|("core::cmp::Eq", _) => {
 318                         let eq_docs = "Checks if two objects are equal given this object's this_arg pointer and another object.";
 319                         writeln!(w, "\t/// {}", eq_docs).unwrap();
 320                         writeln!(w, "\tpub eq: extern \"C\" fn (this_arg: *const c_void, other_arg: &{}) -> bool,", trait_name).unwrap();
 321                         generated_fields.push(("eq".to_owned(), None, Some(format!("\t/** {} */\n", eq_docs))));
 322                 },
 323                 ("std::hash::Hash", _)|("core::hash::Hash", _) => {
 324                         let hash_docs_a = "Calculate a succinct non-cryptographic hash for an object given its this_arg pointer.";
 325                         let hash_docs_b = "This is used, for example, for inclusion of this object in a hash map.";
 326                         writeln!(w, "\t/// {}", hash_docs_a).unwrap();
 327                         writeln!(w, "\t/// {}", hash_docs_b).unwrap();
 328                         writeln!(w, "\tpub hash: extern \"C\" fn (this_arg: *const c_void) -> u64,").unwrap();
 329                         generated_fields.push(("hash".to_owned(), None,
 330                                 Some(format!("\t/**\n\t * {}\n\t * {}\n\t */\n", hash_docs_a, hash_docs_b))));
 331                 },
 332                 ("Send", _) => {}, ("Sync", _) => {},
 333                 (s, i) => {
 334                         // TODO: Both of the below should expose supertrait methods in C++, but doing so is
 335                         // nontrivial.
 336                         generated_fields.push(if types.crate_types.traits.get(s).is_none() {
 337                                 let (docs, name, ret) = convert_trait_impl_field(s);
 338                                 writeln!(w, "\t/// {}", docs).unwrap();
 339                                 writeln!(w, "\tpub {}: extern \"C\" fn (this_arg: *const c_void) -> {},", name, ret).unwrap();
 340                                 (name, None, None) // Assume clonable
 341                         } else {
 342                                 // For in-crate supertraits, just store a C-mapped copy of the supertrait as a member.
 343                                 writeln!(w, "\t/// Implementation of {} for this object.", i).unwrap();
 344                                 let is_clonable = types.is_clonable(s);
 345                                 writeln!(w, "\tpub {}: crate::{},", i, s).unwrap();
 346                                 (format!("{}", i), if !is_clonable {
 347                                         Some(format!("crate::{}_clone_fields", s))
 348                                 } else { None }, None)
 349                         });
 350                 }
 351         ) );
 352         writeln!(w, "\t/// Frees any resources associated with this object given its this_arg pointer.").unwrap();
 353         writeln!(w, "\t/// Does not need to free the outer struct containing function pointers and may be NULL is no resources need to be freed.").unwrap();
 354         writeln!(w, "\tpub free: Option<extern \"C\" fn(this_arg: *mut c_void)>,").unwrap();
 355         generated_fields.push(("free".to_owned(), None, None));
 356         writeln!(w, "}}").unwrap();
 357
 358         macro_rules! impl_trait_for_c {
 359                 ($t: expr, $impl_accessor: expr, $type_resolver: expr) => {
 360                         for item in $t.items.iter() {
 361                                 match item {
 362                                         syn::TraitItem::Method(m) => {
 363                                                 if let ExportStatus::TestOnly = export_status(&m.attrs) { continue; }
 364                                                 if m.default.is_some() { unimplemented!(); }
 365                                                 if m.sig.constness.is_some() || m.sig.asyncness.is_some() || m.sig.unsafety.is_some() ||
 366                                                                 m.sig.abi.is_some() || m.sig.variadic.is_some() {
 367                                                         unimplemented!();
 368                                                 }
 369                                                 let mut meth_gen_types = gen_types.push_ctx();
 370                                                 assert!(meth_gen_types.learn_generics(&m.sig.generics, $type_resolver));
 371                                                 write!(w, "\tfn {}", m.sig.ident).unwrap();
 372                                                 $type_resolver.write_rust_generic_param(w, Some(&meth_gen_types), m.sig.generics.params.iter());
 373                                                 write!(w, "(").unwrap();
 374                                                 for inp in m.sig.inputs.iter() {
 375                                                         match inp {
 376                                                                 syn::FnArg::Receiver(recv) => {
 377                                                                         if !recv.attrs.is_empty() || recv.reference.is_none() { unimplemented!(); }
 378                                                                         write!(w, "&").unwrap();
 379                                                                         if let Some(lft) = &recv.reference.as_ref().unwrap().1 {
 380                                                                                 write!(w, "'{} ", lft.ident).unwrap();
 381                                                                         }
 382                                                                         if recv.mutability.is_some() {
 383                                                                                 write!(w, "mut self").unwrap();
 384                                                                         } else {
 385                                                                                 write!(w, "self").unwrap();
 386                                                                         }
 387                                                                 },
 388                                                                 syn::FnArg::Typed(arg) => {
 389                                                                         if !arg.attrs.is_empty() { unimplemented!(); }
 390                                                                         match &*arg.pat {
 391                                                                                 syn::Pat::Ident(ident) => {
 392                                                                                         if !ident.attrs.is_empty() || ident.by_ref.is_some() ||
 393                                                                                                         ident.mutability.is_some() || ident.subpat.is_some() {
 394                                                                                                 unimplemented!();
 395                                                                                         }
 396                                                                                         write!(w, ", mut {}{}: ", if $type_resolver.skip_arg(&*arg.ty, Some(&meth_gen_types)) { "_" } else { "" }, ident.ident).unwrap();
 397                                                                                 }
 398                                                                                 _ => unimplemented!(),
 399                                                                         }
 400                                                                         $type_resolver.write_rust_type(w, Some(&meth_gen_types), &*arg.ty);
 401                                                                 }
 402                                                         }
 403                                                 }
 404                                                 write!(w, ")").unwrap();
 405                                                 match &m.sig.output {
 406                                                         syn::ReturnType::Type(_, rtype) => {
 407                                                                 write!(w, " -> ").unwrap();
 408                                                                 $type_resolver.write_rust_type(w, Some(&meth_gen_types), &*rtype)
 409                                                         },
 410                                                         _ => {},
 411                                                 }
 412                                                 write!(w, " {{\n\t\t").unwrap();
 413                                                 match export_status(&m.attrs) {
 414                                                         ExportStatus::NoExport => {
 415                                                                 unimplemented!();
 416                                                         },
 417                                                         _ => {},
 418                                                 }
 419                                                 if let syn::ReturnType::Type(_, rtype) = &m.sig.output {
 420                                                         if let syn::Type::Reference(r) = &**rtype {
 421                                                                 assert_eq!(m.sig.inputs.len(), 1); // Must only take self!
 422                                                                 writeln!(w, "if let Some(f) = self{}.set_{} {{", $impl_accessor, m.sig.ident).unwrap();
 423                                                                 writeln!(w, "\t\t\t(f)(&self{});", $impl_accessor).unwrap();
 424                                                                 write!(w, "\t\t}}\n\t\t").unwrap();
 425                                                                 $type_resolver.write_from_c_conversion_to_ref_prefix(w, &*r.elem, Some(&meth_gen_types));
 426                                                                 write!(w, "self{}.{}", $impl_accessor, m.sig.ident).unwrap();
 427                                                                 $type_resolver.write_from_c_conversion_to_ref_suffix(w, &*r.elem, Some(&meth_gen_types));
 428                                                                 writeln!(w, "\n\t}}").unwrap();
 429                                                                 continue;
 430                                                         }
 431                                                 }
 432                                                 write_method_var_decl_body(w, &m.sig, "\t", $type_resolver, Some(&meth_gen_types), true);
 433                                                 write!(w, "(self{}.{})(", $impl_accessor, m.sig.ident).unwrap();
 434                                                 let mut args = Vec::new();
 435                                                 write_method_call_params(&mut args, &m.sig, "\t", $type_resolver, Some(&meth_gen_types), "", true);
 436                                                 w.write_all(String::from_utf8(args).unwrap().replace("self", &format!("self{}", $impl_accessor)).as_bytes()).unwrap();
 437
 438                                                 writeln!(w, "\n\t}}").unwrap();
 439                                         },
 440                                         &syn::TraitItem::Type(ref t) => {
 441                                                 if t.default.is_some() || t.generics.lt_token.is_some() { unimplemented!(); }
 442                                                 let mut bounds_iter = t.bounds.iter();
 443                                                 match bounds_iter.next().unwrap() {
 444                                                         syn::TypeParamBound::Trait(tr) => {
 445                                                                 writeln!(w, "\ttype {} = crate::{};", t.ident, $type_resolver.resolve_path(&tr.path, Some(&gen_types))).unwrap();
 446                                                         },
 447                                                         _ => unimplemented!(),
 448                                                 }
 449                                                 if bounds_iter.next().is_some() { unimplemented!(); }
 450                                         },
 451                                         _ => unimplemented!(),
 452                                 }
 453                         }
 454                 }
 455         }
 456
 457         writeln!(w, "unsafe impl Send for {} {{}}", trait_name).unwrap();
 458         writeln!(w, "unsafe impl Sync for {} {{}}", trait_name).unwrap();
 459
 460         writeln!(w, "#[no_mangle]").unwrap();
 461         writeln!(w, "pub(crate) extern \"C\" fn {}_clone_fields(orig: &{}) -> {} {{", trait_name, trait_name, trait_name).unwrap();
 462         writeln!(w, "\t{} {{", trait_name).unwrap();
 463         writeln!(w, "\t\tthis_arg: orig.this_arg,").unwrap();
 464         for (field, clone_fn, _) in generated_fields.iter() {
 465                 if let Some(f) = clone_fn {
 466                         // If the field isn't clonable, blindly assume its a trait and hope for the best.
 467                         writeln!(w, "\t\t{}: {}(&orig.{}),", field, f, field).unwrap();
 468                 } else {
 469                         writeln!(w, "\t\t{}: Clone::clone(&orig.{}),", field, field).unwrap();
 470                 }
 471         }
 472         writeln!(w, "\t}}\n}}").unwrap();
 473
 474         // Implement supertraits for the C-mapped struct.
 475         walk_supertraits!(t, Some(&types), (
 476                 ("std::cmp::Eq", _)|("core::cmp::Eq", _) => {
 477                         writeln!(w, "impl std::cmp::Eq for {} {{}}", trait_name).unwrap();
 478                         writeln!(w, "impl std::cmp::PartialEq for {} {{", trait_name).unwrap();
 479                         writeln!(w, "\tfn eq(&self, o: &Self) -> bool {{ (self.eq)(self.this_arg, o) }}\n}}").unwrap();
 480                 },
 481                 ("std::hash::Hash", _)|("core::hash::Hash", _) => {
 482                         writeln!(w, "impl std::hash::Hash for {} {{", trait_name).unwrap();
 483                         writeln!(w, "\tfn hash<H: std::hash::Hasher>(&self, hasher: &mut H) {{ hasher.write_u64((self.hash)(self.this_arg)) }}\n}}").unwrap();
 484                 },
 485                 ("Send", _) => {}, ("Sync", _) => {},
 486                 ("Clone", _) => {
 487                         writeln!(w, "#[no_mangle]").unwrap();
 488                         writeln!(w, "/// Creates a copy of a {}", trait_name).unwrap();
 489                         writeln!(w, "pub extern \"C\" fn {}_clone(orig: &{}) -> {} {{", trait_name, trait_name, trait_name).unwrap();
 490                         writeln!(w, "\tlet mut res = {}_clone_fields(orig);", trait_name).unwrap();
 491                         writeln!(w, "\tif let Some(f) = orig.cloned {{ (f)(&mut res) }};").unwrap();
 492                         writeln!(w, "\tres\n}}").unwrap();
 493                         writeln!(w, "impl Clone for {} {{", trait_name).unwrap();
 494                         writeln!(w, "\tfn clone(&self) -> Self {{").unwrap();
 495                         writeln!(w, "\t\t{}_clone(self)", trait_name).unwrap();
 496                         writeln!(w, "\t}}\n}}").unwrap();
 497                 },
 498                 (s, i) => {
 499                         if let Some(supertrait) = types.crate_types.traits.get(s) {
 500                                 let mut module_iter = s.rsplitn(2, "::");
 501                                 module_iter.next().unwrap();
 502                                 let supertrait_module = module_iter.next().unwrap();
 503                                 let imports = ImportResolver::new(supertrait_module.splitn(2, "::").next().unwrap(), &types.crate_types.lib_ast.dependencies,
 504                                         supertrait_module, &types.crate_types.lib_ast.modules.get(supertrait_module).unwrap().items);
 505                                 let resolver = TypeResolver::new(&supertrait_module, imports, types.crate_types);
 506                                 writeln!(w, "impl {} for {} {{", s, trait_name).unwrap();
 507                                 impl_trait_for_c!(supertrait, format!(".{}", i), &resolver);
 508                                 writeln!(w, "}}").unwrap();
 509                         } else {
 510                                 do_write_impl_trait(w, s, i, &trait_name);
 511                         }
 512                 }
 513         ) );
 514
 515         // Finally, implement the original Rust trait for the newly created mapped trait.
 516         writeln!(w, "\nuse {}::{} as rust{};", types.module_path, t.ident, trait_name).unwrap();
 517         if implementable {
 518                 write!(w, "impl rust{}", t.ident).unwrap();
 519                 maybe_write_generics(w, &t.generics, types, false);
 520                 writeln!(w, " for {} {{", trait_name).unwrap();
 521                 impl_trait_for_c!(t, "", types);
 522                 writeln!(w, "}}\n").unwrap();
 523                 writeln!(w, "// We're essentially a pointer already, or at least a set of pointers, so allow us to be used").unwrap();
 524                 writeln!(w, "// directly as a Deref trait in higher-level structs:").unwrap();
 525                 writeln!(w, "impl std::ops::Deref for {} {{\n\ttype Target = Self;", trait_name).unwrap();
 526                 writeln!(w, "\tfn deref(&self) -> &Self {{\n\t\tself\n\t}}\n}}").unwrap();
 527         }
 528
 529         writeln!(w, "/// Calls the free function if one is set").unwrap();
 530         writeln!(w, "#[no_mangle]\npub extern \"C\" fn {}_free(this_ptr: {}) {{ }}", trait_name, trait_name).unwrap();
 531         writeln!(w, "impl Drop for {} {{", trait_name).unwrap();
 532         writeln!(w, "\tfn drop(&mut self) {{").unwrap();
 533         writeln!(w, "\t\tif let Some(f) = self.free {{").unwrap();
 534         writeln!(w, "\t\t\tf(self.this_arg);").unwrap();
 535         writeln!(w, "\t\t}}\n\t}}\n}}").unwrap();
 536
 537         write_cpp_wrapper(cpp_headers, &trait_name, true, Some(generated_fields.drain(..)
 538                 .filter_map(|(name, _, docs)| if let Some(docs) = docs { Some((name, docs)) } else { None }).collect()));
 539 }
 540
 541 /// Write out a simple "opaque" type (eg structs) which contain a pointer to the native Rust type
 542 /// and a flag to indicate whether Drop'ing the mapped struct drops the underlying Rust type.
 543 ///
 544 /// Also writes out a _free function and a C++ wrapper which handles calling _free.
 545 fn writeln_opaque<W: std::io::Write>(w: &mut W, ident: &syn::Ident, struct_name: &str, generics: &syn::Generics, attrs: &[syn::Attribute], types: &TypeResolver, extra_headers: &mut File, cpp_headers: &mut File) {
 546         // If we directly read the original type by its original name, cbindgen hits
 547         // https://github.com/eqrion/cbindgen/issues/286 Thus, instead, we import it as a temporary
 548         // name and then reference it by that name, which works around the issue.
 549         write!(w, "\nuse {}::{} as native{}Import;\ntype native{} = native{}Import", types.module_path, ident, ident, ident, ident).unwrap();
 550         maybe_write_generics(w, &generics, &types, true);
 551         writeln!(w, ";\n").unwrap();
 552         writeln!(extra_headers, "struct native{}Opaque;\ntypedef struct native{}Opaque LDKnative{};", ident, ident, ident).unwrap();
 553         writeln_docs(w, &attrs, "");
 554         writeln!(w, "#[must_use]\n#[repr(C)]\npub struct {} {{", struct_name).unwrap();
 555         writeln!(w, "\t/// A pointer to the opaque Rust object.\n").unwrap();
 556         writeln!(w, "\t/// Nearly everywhere, inner must be non-null, however in places where").unwrap();
 557         writeln!(w, "\t/// the Rust equivalent takes an Option, it may be set to null to indicate None.").unwrap();
 558         writeln!(w, "\tpub inner: *mut native{},", ident).unwrap();
 559         writeln!(w, "\t/// Indicates that this is the only struct which contains the same pointer.\n").unwrap();
 560         writeln!(w, "\t/// Rust functions which take ownership of an object provided via an argument require").unwrap();
 561         writeln!(w, "\t/// this to be true and invalidate the object pointed to by inner.").unwrap();
 562         writeln!(w, "\tpub is_owned: bool,").unwrap();
 563         writeln!(w, "}}\n").unwrap();
 564         writeln!(w, "impl Drop for {} {{\n\tfn drop(&mut self) {{", struct_name).unwrap();
 565         writeln!(w, "\t\tif self.is_owned && !<*mut native{}>::is_null(self.inner) {{", ident).unwrap();
 566         writeln!(w, "\t\t\tlet _ = unsafe {{ Box::from_raw(self.inner) }};\n\t\t}}\n\t}}\n}}").unwrap();
 567         writeln!(w, "/// Frees any resources used by the {}, if is_owned is set and inner is non-NULL.", struct_name).unwrap();
 568         writeln!(w, "#[no_mangle]\npub extern \"C\" fn {}_free(this_obj: {}) {{ }}", struct_name, struct_name).unwrap();
 569         writeln!(w, "#[allow(unused)]").unwrap();
 570         writeln!(w, "/// Used only if an object of this type is returned as a trait impl by a method").unwrap();
 571         writeln!(w, "extern \"C\" fn {}_free_void(this_ptr: *mut c_void) {{", struct_name).unwrap();
 572         writeln!(w, "\tunsafe {{ let _ = Box::from_raw(this_ptr as *mut native{}); }}\n}}", struct_name).unwrap();
 573         writeln!(w, "#[allow(unused)]").unwrap();
 574         writeln!(w, "/// When moving out of the pointer, we have to ensure we aren't a reference, this makes that easy").unwrap();
 575         writeln!(w, "impl {} {{", struct_name).unwrap();
 576         writeln!(w, "\tpub(crate) fn take_inner(mut self) -> *mut native{} {{", struct_name).unwrap();
 577         writeln!(w, "\t\tassert!(self.is_owned);").unwrap();
 578         writeln!(w, "\t\tlet ret = self.inner;").unwrap();
 579         writeln!(w, "\t\tself.inner = std::ptr::null_mut();").unwrap();
 580         writeln!(w, "\t\tret").unwrap();
 581         writeln!(w, "\t}}\n}}").unwrap();
 582
 583         write_cpp_wrapper(cpp_headers, &format!("{}", ident), true, None);
 584 }
 585
 586 /// Writes out all the relevant mappings for a Rust struct, deferring to writeln_opaque to generate
 587 /// the struct itself, and then writing getters and setters for public, understood-type fields and
 588 /// a constructor if every field is public.
 589 fn writeln_struct<'a, 'b, W: std::io::Write>(w: &mut W, s: &'a syn::ItemStruct, types: &mut TypeResolver<'b, 'a>, extra_headers: &mut File, cpp_headers: &mut File) {
 590         if export_status(&s.attrs) != ExportStatus::Export { return; }
 591
 592         let struct_name = &format!("{}", s.ident);
 593         writeln_opaque(w, &s.ident, struct_name, &s.generics, &s.attrs, types, extra_headers, cpp_headers);
 594
 595         if let syn::Fields::Named(fields) = &s.fields {
 596                 let mut self_path_segs = syn::punctuated::Punctuated::new();
 597                 self_path_segs.push(s.ident.clone().into());
 598                 let self_path = syn::Path { leading_colon: None, segments: self_path_segs};
 599                 let mut gen_types = GenericTypes::new(Some((types.resolve_path(&self_path, None), &self_path)));
 600                 assert!(gen_types.learn_generics(&s.generics, types));
 601
 602                 let mut all_fields_settable = true;
 603                 for field in fields.named.iter() {
 604                         if let syn::Visibility::Public(_) = field.vis {
 605                                 let export = export_status(&field.attrs);
 606                                 match export {
 607                                         ExportStatus::Export => {},
 608                                         ExportStatus::NoExport|ExportStatus::TestOnly => {
 609                                                 all_fields_settable = false;
 610                                                 continue
 611                                         },
 612                                         ExportStatus::NotImplementable => panic!("(C-not implementable) must only appear on traits"),
 613                                 }
 614
 615                                 if let Some(ident) = &field.ident {
 616                                         let ref_type = syn::Type::Reference(syn::TypeReference {
 617                                                 and_token: syn::Token!(&)(Span::call_site()), lifetime: None, mutability: None,
 618                                                 elem: Box::new(field.ty.clone()) });
 619                                         if types.understood_c_type(&ref_type, Some(&gen_types)) {
 620                                                 writeln_arg_docs(w, &field.attrs, "", types, Some(&gen_types), vec![].drain(..), Some(&ref_type));
 621                                                 write!(w, "#[no_mangle]\npub extern \"C\" fn {}_get_{}(this_ptr: &{}) -> ", struct_name, ident, struct_name).unwrap();
 622                                                 types.write_c_type(w, &ref_type, Some(&gen_types), true);
 623                                                 write!(w, " {{\n\tlet mut inner_val = &mut unsafe {{ &mut *this_ptr.inner }}.{};\n\t", ident).unwrap();
 624                                                 let local_var = types.write_to_c_conversion_new_var(w, &format_ident!("inner_val"), &ref_type, Some(&gen_types), true);
 625                                                 if local_var { write!(w, "\n\t").unwrap(); }
 626                                                 types.write_to_c_conversion_inline_prefix(w, &ref_type, Some(&gen_types), true);
 627                                                 write!(w, "inner_val").unwrap();
 628                                                 types.write_to_c_conversion_inline_suffix(w, &ref_type, Some(&gen_types), true);
 629                                                 writeln!(w, "\n}}").unwrap();
 630                                         }
 631
 632                                         if types.understood_c_type(&field.ty, Some(&gen_types)) {
 633                                                 writeln_arg_docs(w, &field.attrs, "", types, Some(&gen_types), vec![("val".to_owned(), &field.ty)].drain(..), None);
 634                                                 write!(w, "#[no_mangle]\npub extern \"C\" fn {}_set_{}(this_ptr: &mut {}, mut val: ", struct_name, ident, struct_name).unwrap();
 635                                                 types.write_c_type(w, &field.ty, Some(&gen_types), false);
 636                                                 write!(w, ") {{\n\t").unwrap();
 637                                                 let local_var = types.write_from_c_conversion_new_var(w, &format_ident!("val"), &field.ty, Some(&gen_types));
 638                                                 if local_var { write!(w, "\n\t").unwrap(); }
 639                                                 write!(w, "unsafe {{ &mut *this_ptr.inner }}.{} = ", ident).unwrap();
 640                                                 types.write_from_c_conversion_prefix(w, &field.ty, Some(&gen_types));
 641                                                 write!(w, "val").unwrap();
 642                                                 types.write_from_c_conversion_suffix(w, &field.ty, Some(&gen_types));
 643                                                 writeln!(w, ";\n}}").unwrap();
 644                                         } else { all_fields_settable = false; }
 645                                 } else { all_fields_settable = false; }
 646                         } else { all_fields_settable = false; }
 647                 }
 648
 649                 if all_fields_settable {
 650                         // Build a constructor!
 651                         writeln!(w, "/// Constructs a new {} given each field", struct_name).unwrap();
 652                         write!(w, "#[must_use]\n#[no_mangle]\npub extern \"C\" fn {}_new(", struct_name).unwrap();
 653                         for (idx, field) in fields.named.iter().enumerate() {
 654                                 if idx != 0 { write!(w, ", ").unwrap(); }
 655                                 write!(w, "mut {}_arg: ", field.ident.as_ref().unwrap()).unwrap();
 656                                 types.write_c_type(w, &field.ty, Some(&gen_types), false);
 657                         }
 658                         write!(w, ") -> {} {{\n\t", struct_name).unwrap();
 659                         for field in fields.named.iter() {
 660                                 let field_ident = format_ident!("{}_arg", field.ident.as_ref().unwrap());
 661                                 if types.write_from_c_conversion_new_var(w, &field_ident, &field.ty, Some(&gen_types)) {
 662                                         write!(w, "\n\t").unwrap();
 663                                 }
 664                         }
 665                         writeln!(w, "{} {{ inner: Box::into_raw(Box::new(native{} {{", struct_name, s.ident).unwrap();
 666                         for field in fields.named.iter() {
 667                                 write!(w, "\t\t{}: ", field.ident.as_ref().unwrap()).unwrap();
 668                                 types.write_from_c_conversion_prefix(w, &field.ty, Some(&gen_types));
 669                                 write!(w, "{}_arg", field.ident.as_ref().unwrap()).unwrap();
 670                                 types.write_from_c_conversion_suffix(w, &field.ty, Some(&gen_types));
 671                                 writeln!(w, ",").unwrap();
 672                         }
 673                         writeln!(w, "\t}})), is_owned: true }}\n}}").unwrap();
 674                 }
 675         }
 676 }
 677
 678 /// Prints a relevant conversion for impl *
 679 ///
 680 /// For simple impl Struct {}s, this just outputs the wrapper functions as Struct_fn_name() { .. }.
 681 ///
 682 /// For impl Trait for Struct{}s, this non-exported generates wrapper functions as
 683 /// Trait_Struct_fn_name and a Struct_as_Trait(&struct) -> Trait function which returns a populated
 684 /// Trait struct containing a pointer to the passed struct's inner field and the wrapper functions.
 685 ///
 686 /// A few non-crate Traits are hard-coded including Default.
 687 fn writeln_impl<W: std::io::Write>(w: &mut W, i: &syn::ItemImpl, types: &mut TypeResolver) {
 688         match export_status(&i.attrs) {
 689                 ExportStatus::Export => {},
 690                 ExportStatus::NoExport|ExportStatus::TestOnly => return,
 691                 ExportStatus::NotImplementable => panic!("(C-not implementable) must only appear on traits"),
 692         }
 693
 694         if let syn::Type::Tuple(_) = &*i.self_ty {
 695                 if types.understood_c_type(&*i.self_ty, None) {
 696                         let mut gen_types = GenericTypes::new(None);
 697                         if !gen_types.learn_generics(&i.generics, types) {
 698                                 eprintln!("Not implementing anything for `impl (..)` due to not understood generics");
 699                                 return;
 700                         }
 701
 702                         if i.defaultness.is_some() || i.unsafety.is_some() { unimplemented!(); }
 703                         if let Some(trait_path) = i.trait_.as_ref() {
 704                                 if trait_path.0.is_some() { unimplemented!(); }
 705                                 if types.understood_c_path(&trait_path.1) {
 706                                         eprintln!("Not implementing anything for `impl Trait for (..)` - we only support manual defines");
 707                                         return;
 708                                 } else {
 709                                         // Just do a manual implementation:
 710                                         maybe_convert_trait_impl(w, &trait_path.1, &*i.self_ty, types, &gen_types);
 711                                 }
 712                         } else {
 713                                 eprintln!("Not implementing anything for plain `impl (..)` block - we only support `impl Trait for (..)` blocks");
 714                                 return;
 715                         }
 716                 }
 717                 return;
 718         }
 719         if let &syn::Type::Path(ref p) = &*i.self_ty {
 720                 if p.qself.is_some() { unimplemented!(); }
 721                 if let Some(ident) = single_ident_generic_path_to_ident(&p.path) {
 722                         if let Some(resolved_path) = types.maybe_resolve_non_ignored_ident(&ident) {
 723                                 let mut gen_types = GenericTypes::new(Some((resolved_path.clone(), &p.path)));
 724                                 if !gen_types.learn_generics(&i.generics, types) {
 725                                         eprintln!("Not implementing anything for impl {} due to not understood generics", ident);
 726                                         return;
 727                                 }
 728
 729                                 if i.defaultness.is_some() || i.unsafety.is_some() { unimplemented!(); }
 730                                 if let Some(trait_path) = i.trait_.as_ref() {
 731                                         if trait_path.0.is_some() { unimplemented!(); }
 732                                         if types.understood_c_path(&trait_path.1) {
 733                                                 let full_trait_path = types.resolve_path(&trait_path.1, None);
 734                                                 let trait_obj = *types.crate_types.traits.get(&full_trait_path).unwrap();
 735                                                 // We learn the associated types maping from the original trait object.
 736                                                 // That's great, except that they are unresolved idents, so if we learn
 737                                                 // mappings from a trai defined in a different file, we may mis-resolve or
 738                                                 // fail to resolve the mapped types.
 739                                                 gen_types.learn_associated_types(trait_obj, types);
 740                                                 let mut impl_associated_types = HashMap::new();
 741                                                 for item in i.items.iter() {
 742                                                         match item {
 743                                                                 syn::ImplItem::Type(t) => {
 744                                                                         if let syn::Type::Path(p) = &t.ty {
 745                                                                                 if let Some(id) = single_ident_generic_path_to_ident(&p.path) {
 746                                                                                         impl_associated_types.insert(&t.ident, id);
 747                                                                                 }
 748                                                                         }
 749                                                                 },
 750                                                                 _ => {},
 751                                                         }
 752                                                 }
 753
 754                                                 let export = export_status(&trait_obj.attrs);
 755                                                 match export {
 756                                                         ExportStatus::Export|ExportStatus::NotImplementable => {},
 757                                                         ExportStatus::NoExport|ExportStatus::TestOnly => return,
 758                                                 }
 759
 760                                                 // For cases where we have a concrete native object which implements a
 761                                                 // trait and need to return the C-mapped version of the trait, provide a
 762                                                 // From<> implementation which does all the work to ensure free is handled
 763                                                 // properly. This way we can call this method from deep in the
 764                                                 // type-conversion logic without actually knowing the concrete native type.
 765                                                 writeln!(w, "impl From<native{}> for crate::{} {{", ident, full_trait_path).unwrap();
 766                                                 writeln!(w, "\tfn from(obj: native{}) -> Self {{", ident).unwrap();
 767                                                 writeln!(w, "\t\tlet mut rust_obj = {} {{ inner: Box::into_raw(Box::new(obj)), is_owned: true }};", ident).unwrap();
 768                                                 writeln!(w, "\t\tlet mut ret = {}_as_{}(&rust_obj);", ident, trait_obj.ident).unwrap();
 769                                                 writeln!(w, "\t\t// We want to free rust_obj when ret gets drop()'d, not rust_obj, so wipe rust_obj's pointer and set ret's free() fn").unwrap();
 770                                                 writeln!(w, "\t\trust_obj.inner = std::ptr::null_mut();").unwrap();
 771                                                 writeln!(w, "\t\tret.free = Some({}_free_void);", ident).unwrap();
 772                                                 writeln!(w, "\t\tret\n\t}}\n}}").unwrap();
 773
 774                                                 writeln!(w, "/// Constructs a new {} which calls the relevant methods on this_arg.", trait_obj.ident).unwrap();
 775                                                 writeln!(w, "/// This copies the `inner` pointer in this_arg and thus the returned {} must be freed before this_arg is", trait_obj.ident).unwrap();
 776                                                 write!(w, "#[no_mangle]\npub extern \"C\" fn {}_as_{}(this_arg: &{}) -> crate::{} {{\n", ident, trait_obj.ident, ident, full_trait_path).unwrap();
 777                                                 writeln!(w, "\tcrate::{} {{", full_trait_path).unwrap();
 778                                                 writeln!(w, "\t\tthis_arg: unsafe {{ (*this_arg).inner as *mut c_void }},").unwrap();
 779                                                 writeln!(w, "\t\tfree: None,").unwrap();
 780
 781                                                 macro_rules! write_meth {
 782                                                         ($m: expr, $trait: expr, $indent: expr) => {
 783                                                                 let trait_method = $trait.items.iter().filter_map(|item| {
 784                                                                         if let syn::TraitItem::Method(t_m) = item { Some(t_m) } else { None }
 785                                                                 }).find(|trait_meth| trait_meth.sig.ident == $m.sig.ident).unwrap();
 786                                                                 match export_status(&trait_method.attrs) {
 787                                                                         ExportStatus::Export => {},
 788                                                                         ExportStatus::NoExport => {
 789                                                                                 write!(w, "{}\t\t//XXX: Need to export {}\n", $indent, $m.sig.ident).unwrap();
 790                                                                                 continue;
 791                                                                         },
 792                                                                         ExportStatus::TestOnly => continue,
 793                                                                         ExportStatus::NotImplementable => panic!("(C-not implementable) must only appear on traits"),
 794                                                                 }
 795
 796                                                                 let mut printed = false;
 797                                                                 if let syn::ReturnType::Type(_, rtype) = &$m.sig.output {
 798                                                                         if let syn::Type::Reference(r) = &**rtype {
 799                                                                                 write!(w, "\n\t\t{}{}: ", $indent, $m.sig.ident).unwrap();
 800                                                                                 types.write_empty_rust_val(Some(&gen_types), w, &*r.elem);
 801                                                                                 writeln!(w, ",\n{}\t\tset_{}: Some({}_{}_set_{}),", $indent, $m.sig.ident, ident, $trait.ident, $m.sig.ident).unwrap();
 802                                                                                 printed = true;
 803                                                                         }
 804                                                                 }
 805                                                                 if !printed {
 806                                                                         write!(w, "{}\t\t{}: {}_{}_{},\n", $indent, $m.sig.ident, ident, $trait.ident, $m.sig.ident).unwrap();
 807                                                                 }
 808                                                         }
 809                                                 }
 810                                                 for item in trait_obj.items.iter() {
 811                                                         match item {
 812                                                                 syn::TraitItem::Method(m) => {
 813                                                                         write_meth!(m, trait_obj, "");
 814                                                                 },
 815                                                                 _ => {},
 816                                                         }
 817                                                 }
 818                                                 let mut requires_clone = false;
 819                                                 walk_supertraits!(trait_obj, Some(&types), (
 820                                                         ("Clone", _) => {
 821                                                                 requires_clone = true;
 822                                                                 writeln!(w, "\t\tcloned: Some({}_{}_cloned),", trait_obj.ident, ident).unwrap();
 823                                                         },
 824                                                         ("Sync", _) => {}, ("Send", _) => {},
 825                                                         ("std::marker::Sync", _) => {}, ("std::marker::Send", _) => {},
 826                                                         (s, t) => {
 827                                                                 if let Some(supertrait_obj) = types.crate_types.traits.get(s) {
 828                                                                         writeln!(w, "\t\t{}: crate::{} {{", t, s).unwrap();
 829                                                                         writeln!(w, "\t\t\tthis_arg: unsafe {{ (*this_arg).inner as *mut c_void }},").unwrap();
 830                                                                         writeln!(w, "\t\t\tfree: None,").unwrap();
 831                                                                         for item in supertrait_obj.items.iter() {
 832                                                                                 match item {
 833                                                                                         syn::TraitItem::Method(m) => {
 834                                                                                                 write_meth!(m, supertrait_obj, "\t");
 835                                                                                         },
 836                                                                                         _ => {},
 837                                                                                 }
 838                                                                         }
 839                                                                         write!(w, "\t\t}},\n").unwrap();
 840                                                                 } else {
 841                                                                         write_trait_impl_field_assign(w, s, ident);
 842                                                                 }
 843                                                         }
 844                                                 ) );
 845                                                 writeln!(w, "\t}}\n}}\n").unwrap();
 846
 847                                                 macro_rules! impl_meth {
 848                                                         ($m: expr, $trait_path: expr, $trait: expr, $indent: expr) => {
 849                                                                 let trait_method = $trait.items.iter().filter_map(|item| {
 850                                                                         if let syn::TraitItem::Method(t_m) = item { Some(t_m) } else { None }
 851                                                                 }).find(|trait_meth| trait_meth.sig.ident == $m.sig.ident).unwrap();
 852                                                                 match export_status(&trait_method.attrs) {
 853                                                                         ExportStatus::Export => {},
 854                                                                         ExportStatus::NoExport|ExportStatus::TestOnly => continue,
 855                                                                         ExportStatus::NotImplementable => panic!("(C-not implementable) must only appear on traits"),
 856                                                                 }
 857
 858                                                                 if let syn::ReturnType::Type(_, _) = &$m.sig.output {
 859                                                                         writeln!(w, "#[must_use]").unwrap();
 860                                                                 }
 861                                                                 write!(w, "extern \"C\" fn {}_{}_{}(", ident, $trait.ident, $m.sig.ident).unwrap();
 862                                                                 let mut meth_gen_types = gen_types.push_ctx();
 863                                                                 assert!(meth_gen_types.learn_generics(&$m.sig.generics, types));
 864                                                                 write_method_params(w, &$m.sig, "c_void", types, Some(&meth_gen_types), true, true);
 865                                                                 write!(w, " {{\n\t").unwrap();
 866                                                                 write_method_var_decl_body(w, &$m.sig, "", types, Some(&meth_gen_types), false);
 867                                                                 let mut takes_self = false;
 868                                                                 for inp in $m.sig.inputs.iter() {
 869                                                                         if let syn::FnArg::Receiver(_) = inp {
 870                                                                                 takes_self = true;
 871                                                                         }
 872                                                                 }
 873
 874                                                                 let mut t_gen_args = String::new();
 875                                                                 for (idx, _) in $trait.generics.params.iter().enumerate() {
 876                                                                         if idx != 0 { t_gen_args += ", " };
 877                                                                         t_gen_args += "_"
 878                                                                 }
 879                                                                 if takes_self {
 880                                                                         write!(w, "<native{} as {}<{}>>::{}(unsafe {{ &mut *(this_arg as *mut native{}) }}, ", ident, $trait_path, t_gen_args, $m.sig.ident, ident).unwrap();
 881                                                                 } else {
 882                                                                         write!(w, "<native{} as {}<{}>>::{}(", ident, $trait_path, t_gen_args, $m.sig.ident).unwrap();
 883                                                                 }
 884
 885                                                                 let mut real_type = "".to_string();
 886                                                                 match &$m.sig.output {
 887                                                                         syn::ReturnType::Type(_, rtype) => {
 888                                                                                 if let Some(mut remaining_path) = first_seg_self(&*rtype) {
 889                                                                                         if let Some(associated_seg) = get_single_remaining_path_seg(&mut remaining_path) {
 890                                                                                                 real_type = format!("{}", impl_associated_types.get(associated_seg).unwrap());
 891                                                                                         }
 892                                                                                 }
 893                                                                         },
 894                                                                         _ => {},
 895                                                                 }
 896                                                                 write_method_call_params(w, &$m.sig, "", types, Some(&meth_gen_types), &real_type, false);
 897                                                                 write!(w, "\n}}\n").unwrap();
 898                                                                 if let syn::ReturnType::Type(_, rtype) = &$m.sig.output {
 899                                                                         if let syn::Type::Reference(r) = &**rtype {
 900                                                                                 assert_eq!($m.sig.inputs.len(), 1); // Must only take self
 901                                                                                 writeln!(w, "extern \"C\" fn {}_{}_set_{}(trait_self_arg: &{}) {{", ident, $trait.ident, $m.sig.ident, $trait.ident).unwrap();
 902                                                                                 writeln!(w, "\t// This is a bit race-y in the general case, but for our specific use-cases today, we're safe").unwrap();
 903                                                                                 writeln!(w, "\t// Specifically, we must ensure that the first time we're called it can never be in parallel").unwrap();
 904                                                                                 write!(w, "\tif ").unwrap();
 905                                                                                 types.write_empty_rust_val_check(Some(&meth_gen_types), w, &*r.elem, &format!("trait_self_arg.{}", $m.sig.ident));
 906                                                                                 writeln!(w, " {{").unwrap();
 907                                                                                 writeln!(w, "\t\tunsafe {{ &mut *(trait_self_arg as *const {}  as *mut {}) }}.{} = {}_{}_{}(trait_self_arg.this_arg);", $trait.ident, $trait.ident, $m.sig.ident, ident, $trait.ident, $m.sig.ident).unwrap();
 908                                                                                 writeln!(w, "\t}}").unwrap();
 909                                                                                 writeln!(w, "}}").unwrap();
 910                                                                         }
 911                                                                 }
 912                                                         }
 913                                                 }
 914
 915                                                 for item in i.items.iter() {
 916                                                         match item {
 917                                                                 syn::ImplItem::Method(m) => {
 918                                                                         impl_meth!(m, full_trait_path, trait_obj, "");
 919                                                                 },
 920                                                                 syn::ImplItem::Type(_) => {},
 921                                                                 _ => unimplemented!(),
 922                                                         }
 923                                                 }
 924                                                 if requires_clone {
 925                                                         writeln!(w, "extern \"C\" fn {}_{}_cloned(new_obj: &mut crate::{}) {{", trait_obj.ident, ident, full_trait_path).unwrap();
 926                                                         writeln!(w, "\tnew_obj.this_arg = {}_clone_void(new_obj.this_arg);", ident).unwrap();
 927                                                         writeln!(w, "\tnew_obj.free = Some({}_free_void);", ident).unwrap();
 928                                                         walk_supertraits!(trait_obj, Some(&types), (
 929                                                                 (s, t) => {
 930                                                                         if types.crate_types.traits.get(s).is_some() {
 931                                                                                 assert!(!types.is_clonable(s)); // We don't currently support cloning with a clonable supertrait
 932                                                                                 writeln!(w, "\tnew_obj.{}.this_arg = new_obj.this_arg;", t).unwrap();
 933                                                                                 writeln!(w, "\tnew_obj.{}.free = None;", t).unwrap();
 934                                                                         }
 935                                                                 }
 936                                                         ) );
 937                                                         writeln!(w, "}}").unwrap();
 938                                                 }
 939                                                 write!(w, "\n").unwrap();
 940                                         } else if path_matches_nongeneric(&trait_path.1, &["From"]) {
 941                                         } else if path_matches_nongeneric(&trait_path.1, &["Default"]) {
 942                                                 writeln!(w, "/// Creates a \"default\" {}. See struct and individual field documentaiton for details on which values are used.", ident).unwrap();
 943                                                 write!(w, "#[must_use]\n#[no_mangle]\npub extern \"C\" fn {}_default() -> {} {{\n", ident, ident).unwrap();
 944                                                 write!(w, "\t{} {{ inner: Box::into_raw(Box::new(Default::default())), is_owned: true }}\n", ident).unwrap();
 945                                                 write!(w, "}}\n").unwrap();
 946                                         } else if path_matches_nongeneric(&trait_path.1, &["core", "cmp", "PartialEq"]) {
 947                                         } else if path_matches_nongeneric(&trait_path.1, &["core", "cmp", "Eq"]) {
 948                                                 writeln!(w, "/// Checks if two {}s contain equal inner contents.", ident).unwrap();
 949                                                 writeln!(w, "/// This ignores pointers and is_owned flags and looks at the values in fields.").unwrap();
 950                                                 if types.c_type_has_inner_from_path(&resolved_path) {
 951                                                         writeln!(w, "/// Two objects with NULL inner values will be considered \"equal\" here.").unwrap();
 952                                                 }
 953                                                 write!(w, "#[no_mangle]\npub extern \"C\" fn {}_eq(a: &{}, b: &{}) -> bool {{\n", ident, ident, ident).unwrap();
 954                                                 if types.c_type_has_inner_from_path(&resolved_path) {
 955                                                         write!(w, "\tif a.inner == b.inner {{ return true; }}\n").unwrap();
 956                                                         write!(w, "\tif a.inner.is_null() || b.inner.is_null() {{ return false; }}\n").unwrap();
 957                                                 }
 958
 959                                                 let path = &p.path;
 960                                                 let ref_type: syn::Type = syn::parse_quote!(&#path);
 961                                                 assert!(!types.write_to_c_conversion_new_var(w, &format_ident!("a"), &*i.self_ty, Some(&gen_types), false), "We don't support new var conversions when comparing equality");
 962
 963                                                 write!(w, "\tif ").unwrap();
 964                                                 types.write_from_c_conversion_prefix(w, &ref_type, Some(&gen_types));
 965                                                 write!(w, "a").unwrap();
 966                                                 types.write_from_c_conversion_suffix(w, &ref_type, Some(&gen_types));
 967                                                 write!(w, " == ").unwrap();
 968                                                 types.write_from_c_conversion_prefix(w, &ref_type, Some(&gen_types));
 969                                                 write!(w, "b").unwrap();
 970                                                 types.write_from_c_conversion_suffix(w, &ref_type, Some(&gen_types));
 971
 972                                                 writeln!(w, " {{ true }} else {{ false }}\n}}").unwrap();
 973                                         } else if path_matches_nongeneric(&trait_path.1, &["core", "hash", "Hash"]) {
 974                                                 writeln!(w, "/// Checks if two {}s contain equal inner contents.", ident).unwrap();
 975                                                 write!(w, "#[no_mangle]\npub extern \"C\" fn {}_hash(o: &{}) -> u64 {{\n", ident, ident).unwrap();
 976                                                 if types.c_type_has_inner_from_path(&resolved_path) {
 977                                                         write!(w, "\tif o.inner.is_null() {{ return 0; }}\n").unwrap();
 978                                                 }
 979
 980                                                 let path = &p.path;
 981                                                 let ref_type: syn::Type = syn::parse_quote!(&#path);
 982                                                 assert!(!types.write_to_c_conversion_new_var(w, &format_ident!("a"), &*i.self_ty, Some(&gen_types), false), "We don't support new var conversions when comparing equality");
 983
 984                                                 writeln!(w, "\t// Note that we'd love to use std::collections::hash_map::DefaultHasher but it's not in core").unwrap();
 985                                                 writeln!(w, "\t#[allow(deprecated)]").unwrap();
 986                                                 writeln!(w, "\tlet mut hasher = core::hash::SipHasher::new();").unwrap();
 987                                                 write!(w, "\tstd::hash::Hash::hash(").unwrap();
 988                                                 types.write_from_c_conversion_prefix(w, &ref_type, Some(&gen_types));
 989                                                 write!(w, "o").unwrap();
 990                                                 types.write_from_c_conversion_suffix(w, &ref_type, Some(&gen_types));
 991                                                 writeln!(w, ", &mut hasher);").unwrap();
 992                                                 writeln!(w, "\tstd::hash::Hasher::finish(&hasher)\n}}").unwrap();
 993                                         } else if (path_matches_nongeneric(&trait_path.1, &["core", "clone", "Clone"]) || path_matches_nongeneric(&trait_path.1, &["Clone"])) &&
 994                                                         types.c_type_has_inner_from_path(&resolved_path) {
 995                                                 writeln!(w, "impl Clone for {} {{", ident).unwrap();
 996                                                 writeln!(w, "\tfn clone(&self) -> Self {{").unwrap();
 997                                                 writeln!(w, "\t\tSelf {{").unwrap();
 998                                                 writeln!(w, "\t\t\tinner: if <*mut native{}>::is_null(self.inner) {{ std::ptr::null_mut() }} else {{", ident).unwrap();
 999                                                 writeln!(w, "\t\t\t\tBox::into_raw(Box::new(unsafe {{ &*self.inner }}.clone())) }},").unwrap();
1000                                                 writeln!(w, "\t\t\tis_owned: true,").unwrap();
1001                                                 writeln!(w, "\t\t}}\n\t}}\n}}").unwrap();
1002                                                 writeln!(w, "#[allow(unused)]").unwrap();
1003                                                 writeln!(w, "/// Used only if an object of this type is returned as a trait impl by a method").unwrap();
1004                                                 writeln!(w, "pub(crate) extern \"C\" fn {}_clone_void(this_ptr: *const c_void) -> *mut c_void {{", ident).unwrap();
1005                                                 writeln!(w, "\tBox::into_raw(Box::new(unsafe {{ (*(this_ptr as *mut native{})).clone() }})) as *mut c_void", ident).unwrap();
1006                                                 writeln!(w, "}}").unwrap();
1007                                                 writeln!(w, "#[no_mangle]").unwrap();
1008                                                 writeln!(w, "/// Creates a copy of the {}", ident).unwrap();
1009                                                 writeln!(w, "pub extern \"C\" fn {}_clone(orig: &{}) -> {} {{", ident, ident, ident).unwrap();
1010                                                 writeln!(w, "\torig.clone()").unwrap();
1011                                                 writeln!(w, "}}").unwrap();
1012                                         } else if path_matches_nongeneric(&trait_path.1, &["FromStr"]) {
1013                                                 if let Some(container) = types.get_c_mangled_container_type(
1014                                                                 vec![&*i.self_ty, &syn::Type::Tuple(syn::TypeTuple { paren_token: Default::default(), elems: syn::punctuated::Punctuated::new() })],
1015                                                                 Some(&gen_types), "Result") {
1016                                                         writeln!(w, "#[no_mangle]").unwrap();
1017                                                         writeln!(w, "/// Read a {} object from a string", ident).unwrap();
1018                                                         writeln!(w, "pub extern \"C\" fn {}_from_str(s: crate::c_types::Str) -> {} {{", ident, container).unwrap();
1019                                                         writeln!(w, "\tmatch {}::from_str(s.into_str()) {{", resolved_path).unwrap();
1020                                                         writeln!(w, "\t\tOk(r) => {{").unwrap();
1021                                                         let new_var = types.write_to_c_conversion_new_var(w, &format_ident!("r"), &*i.self_ty, Some(&gen_types), false);
1022                                                         write!(w, "\t\t\tcrate::c_types::CResultTempl::ok(\n\t\t\t\t").unwrap();
1023                                                         types.write_to_c_conversion_inline_prefix(w, &*i.self_ty, Some(&gen_types), false);
1024                                                         write!(w, "{}r", if new_var { "local_" } else { "" }).unwrap();
1025                                                         types.write_to_c_conversion_inline_suffix(w, &*i.self_ty, Some(&gen_types), false);
1026                                                         writeln!(w, "\n\t\t\t)\n\t\t}},").unwrap();
1027                                                         writeln!(w, "\t\tErr(e) => crate::c_types::CResultTempl::err(()),").unwrap();
1028                                                         writeln!(w, "\t}}.into()\n}}").unwrap();
1029                                                 }
1030                                         } else if path_matches_nongeneric(&trait_path.1, &["Display"]) {
1031                                                 writeln!(w, "#[no_mangle]").unwrap();
1032                                                 writeln!(w, "/// Get the string representation of a {} object", ident).unwrap();
1033                                                 writeln!(w, "pub extern \"C\" fn {}_to_str(o: &crate::{}) -> Str {{", ident, resolved_path).unwrap();
1034
1035                                                 let self_ty = &i.self_ty;
1036                                                 let ref_type: syn::Type = syn::parse_quote!(&#self_ty);
1037                                                 let new_var = types.write_from_c_conversion_new_var(w, &format_ident!("o"), &ref_type, Some(&gen_types));
1038                                                 write!(w, "\tformat!(\"{{}}\", ").unwrap();
1039                                                 types.write_from_c_conversion_prefix(w, &ref_type, Some(&gen_types));
1040                                                 write!(w, "{}o", if new_var { "local_" } else { "" }).unwrap();
1041                                                 types.write_from_c_conversion_suffix(w, &ref_type, Some(&gen_types));
1042                                                 writeln!(w, ").into()").unwrap();
1043
1044                                                 writeln!(w, "}}").unwrap();
1045                                         } else {
1046                                                 //XXX: implement for other things like ToString
1047                                                 // If we have no generics, try a manual implementation:
1048                                                 maybe_convert_trait_impl(w, &trait_path.1, &*i.self_ty, types, &gen_types);
1049                                         }
1050                                 } else {
1051                                         let declared_type = (*types.get_declared_type(&ident).unwrap()).clone();
1052                                         for item in i.items.iter() {
1053                                                 match item {
1054                                                         syn::ImplItem::Method(m) => {
1055                                                                 if let syn::Visibility::Public(_) = m.vis {
1056                                                                         match export_status(&m.attrs) {
1057                                                                                 ExportStatus::Export => {},
1058                                                                                 ExportStatus::NoExport|ExportStatus::TestOnly => continue,
1059                                                                                 ExportStatus::NotImplementable => panic!("(C-not implementable) must only appear on traits"),
1060                                                                         }
1061                                                                         let mut meth_gen_types = gen_types.push_ctx();
1062                                                                         assert!(meth_gen_types.learn_generics(&m.sig.generics, types));
1063                                                                         if m.defaultness.is_some() { unimplemented!(); }
1064                                                                         writeln_fn_docs(w, &m.attrs, "", types, Some(&meth_gen_types), m.sig.inputs.iter(), &m.sig.output);
1065                                                                         if let syn::ReturnType::Type(_, _) = &m.sig.output {
1066                                                                                 writeln!(w, "#[must_use]").unwrap();
1067                                                                         }
1068                                                                         write!(w, "#[no_mangle]\npub extern \"C\" fn {}_{}(", ident, m.sig.ident).unwrap();
1069                                                                         let ret_type = match &declared_type {
1070                                                                                 DeclType::MirroredEnum => format!("{}", ident),
1071                                                                                 DeclType::StructImported => format!("{}", ident),
1072                                                                                 _ => unimplemented!(),
1073                                                                         };
1074                                                                         write_method_params(w, &m.sig, &ret_type, types, Some(&meth_gen_types), false, true);
1075                                                                         write!(w, " {{\n\t").unwrap();
1076                                                                         write_method_var_decl_body(w, &m.sig, "", types, Some(&meth_gen_types), false);
1077                                                                         let mut takes_self = false;
1078                                                                         let mut takes_mut_self = false;
1079                                                                         let mut takes_owned_self = false;
1080                                                                         for inp in m.sig.inputs.iter() {
1081                                                                                 if let syn::FnArg::Receiver(r) = inp {
1082                                                                                         takes_self = true;
1083                                                                                         if r.mutability.is_some() { takes_mut_self = true; }
1084                                                                                         if r.reference.is_none() { takes_owned_self = true; }
1085                                                                                 }
1086                                                                         }
1087                                                                         if !takes_mut_self && !takes_self {
1088                                                                                 write!(w, "{}::{}(", resolved_path, m.sig.ident).unwrap();
1089                                                                         } else {
1090                                                                                 match &declared_type {
1091                                                                                         DeclType::MirroredEnum => write!(w, "this_arg.to_native().{}(", m.sig.ident).unwrap(),
1092                                                                                         DeclType::StructImported => {
1093                                                                                                 if takes_owned_self {
1094                                                                                                         write!(w, "(*unsafe {{ Box::from_raw(this_arg.take_inner()) }}).{}(", m.sig.ident).unwrap();
1095                                                                                                 } else if takes_mut_self {
1096                                                                                                         write!(w, "unsafe {{ &mut (*(this_arg.inner as *mut native{})) }}.{}(", ident, m.sig.ident).unwrap();
1097                                                                                                 } else {
1098                                                                                                         write!(w, "unsafe {{ &*this_arg.inner }}.{}(", m.sig.ident).unwrap();
1099                                                                                                 }
1100                                                                                         },
1101                                                                                         _ => unimplemented!(),
1102                                                                                 }
1103                                                                         }
1104                                                                         write_method_call_params(w, &m.sig, "", types, Some(&meth_gen_types), &ret_type, false);
1105                                                                         writeln!(w, "\n}}\n").unwrap();
1106                                                                 }
1107                                                         },
1108                                                         _ => {},
1109                                                 }
1110                                         }
1111                                 }
1112                         } else if let Some(resolved_path) = types.maybe_resolve_ident(&ident) {
1113                                 if let Some(aliases) = types.crate_types.reverse_alias_map.get(&resolved_path).cloned() {
1114                                         'alias_impls: for (alias, arguments) in aliases {
1115                                                 let alias_resolved = types.resolve_path(&alias, None);
1116                                                 for (idx, gen) in i.generics.params.iter().enumerate() {
1117                                                         match gen {
1118                                                                 syn::GenericParam::Type(type_param) => {
1119                                                                         'bounds_check: for bound in type_param.bounds.iter() {
1120                                                                                 if let syn::TypeParamBound::Trait(trait_bound) = bound {
1121                                                                                         if let syn::PathArguments::AngleBracketed(ref t) = &arguments {
1122                                                                                                 assert!(idx < t.args.len());
1123                                                                                                 if let syn::GenericArgument::Type(syn::Type::Path(p)) = &t.args[idx] {
1124                                                                                                         let generic_arg = types.resolve_path(&p.path, None);
1125                                                                                                         let generic_bound = types.resolve_path(&trait_bound.path, None);
1126                                                                                                         if let Some(traits_impld) = types.crate_types.trait_impls.get(&generic_arg) {
1127                                                                                                                 for trait_impld in traits_impld {
1128                                                                                                                         if *trait_impld == generic_bound { continue 'bounds_check; }
1129                                                                                                                 }
1130                                                                                                                 eprintln!("struct {}'s generic arg {} didn't match bound {}", alias_resolved, generic_arg, generic_bound);
1131                                                                                                                 continue 'alias_impls;
1132                                                                                                         } else {
1133                                                                                                                 eprintln!("struct {}'s generic arg {} didn't match bound {}", alias_resolved, generic_arg, generic_bound);
1134                                                                                                                 continue 'alias_impls;
1135                                                                                                         }
1136                                                                                                 } else { unimplemented!(); }
1137                                                                                         } else { unimplemented!(); }
1138                                                                                 } else { unimplemented!(); }
1139                                                                         }
1140                                                                 },
1141                                                                 syn::GenericParam::Lifetime(_) => {},
1142                                                                 syn::GenericParam::Const(_) => unimplemented!(),
1143                                                         }
1144                                                 }
1145                                                 let aliased_impl = syn::ItemImpl {
1146                                                         attrs: i.attrs.clone(),
1147                                                         brace_token: syn::token::Brace(Span::call_site()),
1148                                                         defaultness: None,
1149                                                         generics: syn::Generics {
1150                                                                 lt_token: None,
1151                                                                 params: syn::punctuated::Punctuated::new(),
1152                                                                 gt_token: None,
1153                                                                 where_clause: None,
1154                                                         },
1155                                                         impl_token: syn::Token![impl](Span::call_site()),
1156                                                         items: i.items.clone(),
1157                                                         self_ty: Box::new(syn::Type::Path(syn::TypePath { qself: None, path: alias.clone() })),
1158                                                         trait_: i.trait_.clone(),
1159                                                         unsafety: None,
1160                                                 };
1161                                                 writeln_impl(w, &aliased_impl, types);
1162                                         }
1163                                 } else {
1164                                         eprintln!("Not implementing anything for {} due to it being marked not exported", ident);
1165                                 }
1166                         } else {
1167                                 eprintln!("Not implementing anything for {} due to no-resolve (probably the type isn't pub)", ident);
1168                         }
1169                 }
1170         }
1171 }
1172
1173 /// Replaces upper case charachters with underscore followed by lower case except the first
1174 /// charachter and repeated upper case characthers (which are only made lower case).
1175 fn camel_to_snake_case(camel: &str) -> String {
1176         let mut res = "".to_string();
1177         let mut last_upper = -1;
1178         for (idx, c) in camel.chars().enumerate() {
1179                 if c.is_uppercase() {
1180                         if last_upper != idx as isize - 1 { res.push('_'); }
1181                         res.push(c.to_lowercase().next().unwrap());
1182                         last_upper = idx as isize;
1183                 } else {
1184                         res.push(c);
1185                 }
1186         }
1187         res
1188 }
1189
1190
1191 /// Print a mapping of an enum. If all of the enum's fields are C-mapped in some form (or the enum
1192 /// is unitary), we generate an equivalent enum with all types replaced with their C mapped
1193 /// versions followed by conversion functions which map between the Rust version and the C mapped
1194 /// version.
1195 fn writeln_enum<'a, 'b, W: std::io::Write>(w: &mut W, e: &'a syn::ItemEnum, types: &mut TypeResolver<'b, 'a>, extra_headers: &mut File, cpp_headers: &mut File) {
1196         match export_status(&e.attrs) {
1197                 ExportStatus::Export => {},
1198                 ExportStatus::NoExport|ExportStatus::TestOnly => return,
1199                 ExportStatus::NotImplementable => panic!("(C-not implementable) must only appear on traits"),
1200         }
1201
1202         if is_enum_opaque(e) {
1203                 eprintln!("Skipping enum {} as it contains non-unit fields", e.ident);
1204                 writeln_opaque(w, &e.ident, &format!("{}", e.ident), &e.generics, &e.attrs, types, extra_headers, cpp_headers);
1205                 return;
1206         }
1207         writeln_docs(w, &e.attrs, "");
1208
1209         let mut gen_types = GenericTypes::new(None);
1210         assert!(gen_types.learn_generics(&e.generics, types));
1211
1212         let mut needs_free = false;
1213         let mut constr = Vec::new();
1214
1215         writeln!(w, "#[must_use]\n#[derive(Clone)]\n#[repr(C)]\npub enum {} {{", e.ident).unwrap();
1216         for var in e.variants.iter() {
1217                 assert_eq!(export_status(&var.attrs), ExportStatus::Export); // We can't partially-export a mirrored enum
1218                 writeln_docs(w, &var.attrs, "\t");
1219                 write!(w, "\t{}", var.ident).unwrap();
1220                 writeln!(&mut constr, "#[no_mangle]\n/// Utility method to constructs a new {}-variant {}", var.ident, e.ident).unwrap();
1221                 let constr_name = camel_to_snake_case(&format!("{}", var.ident));
1222                 write!(&mut constr, "pub extern \"C\" fn {}_{}(", e.ident, constr_name).unwrap();
1223                 let mut empty_tuple_variant = false;
1224                 if let syn::Fields::Named(fields) = &var.fields {
1225                         needs_free = true;
1226                         writeln!(w, " {{").unwrap();
1227                         for (idx, field) in fields.named.iter().enumerate() {
1228                                 if export_status(&field.attrs) == ExportStatus::TestOnly { continue; }
1229                                 writeln_field_docs(w, &field.attrs, "\t\t", types, Some(&gen_types), &field.ty);
1230                                 write!(w, "\t\t{}: ", field.ident.as_ref().unwrap()).unwrap();
1231                                 write!(&mut constr, "{}{}: ", if idx != 0 { ", " } else { "" }, field.ident.as_ref().unwrap()).unwrap();
1232                                 types.write_c_type(w, &field.ty, Some(&gen_types), false);
1233                                 types.write_c_type(&mut constr, &field.ty, Some(&gen_types), false);
1234                                 writeln!(w, ",").unwrap();
1235                         }
1236                         write!(w, "\t}}").unwrap();
1237                 } else if let syn::Fields::Unnamed(fields) = &var.fields {
1238                         if fields.unnamed.len() == 1 {
1239                                 let mut empty_check = Vec::new();
1240                                 types.write_c_type(&mut empty_check, &fields.unnamed[0].ty, Some(&gen_types), false);
1241                                 if empty_check.is_empty() {
1242                                         empty_tuple_variant = true;
1243                                 }
1244                         }
1245                         if !empty_tuple_variant {
1246                                 needs_free = true;
1247                                 write!(w, "(").unwrap();
1248                                 for (idx, field) in fields.unnamed.iter().enumerate() {
1249                                         if export_status(&field.attrs) == ExportStatus::TestOnly { continue; }
1250                                         write!(&mut constr, "{}: ", ('a' as u8 + idx as u8) as char).unwrap();
1251                                         types.write_c_type(w, &field.ty, Some(&gen_types), false);
1252                                         types.write_c_type(&mut constr, &field.ty, Some(&gen_types), false);
1253                                         if idx != fields.unnamed.len() - 1 {
1254                                                 write!(w, ",").unwrap();
1255                                                 write!(&mut constr, ",").unwrap();
1256                                         }
1257                                 }
1258                                 write!(w, ")").unwrap();
1259                         }
1260                 }
1261                 if var.discriminant.is_some() { unimplemented!(); }
1262                 write!(&mut constr, ") -> {} {{\n\t{}::{}", e.ident, e.ident, var.ident).unwrap();
1263                 if let syn::Fields::Named(fields) = &var.fields {
1264                         writeln!(&mut constr, " {{").unwrap();
1265                         for field in fields.named.iter() {
1266                                 writeln!(&mut constr, "\t\t{},", field.ident.as_ref().unwrap()).unwrap();
1267                         }
1268                         writeln!(&mut constr, "\t}}").unwrap();
1269                 } else if let syn::Fields::Unnamed(fields) = &var.fields {
1270                         if !empty_tuple_variant {
1271                                 write!(&mut constr, "(").unwrap();
1272                                 for idx in 0..fields.unnamed.len() {
1273                                         write!(&mut constr, "{}, ", ('a' as u8 + idx as u8) as char).unwrap();
1274                                 }
1275                                 writeln!(&mut constr, ")").unwrap();
1276                         } else {
1277                                 writeln!(&mut constr, "").unwrap();
1278                         }
1279                 }
1280                 writeln!(&mut constr, "}}").unwrap();
1281                 writeln!(w, ",").unwrap();
1282         }
1283         writeln!(w, "}}\nuse {}::{} as native{};\nimpl {} {{", types.module_path, e.ident, e.ident, e.ident).unwrap();
1284
1285         macro_rules! write_conv {
1286                 ($fn_sig: expr, $to_c: expr, $ref: expr) => {
1287                         writeln!(w, "\t#[allow(unused)]\n\tpub(crate) fn {} {{\n\t\tmatch {} {{", $fn_sig, if $to_c { "native" } else { "self" }).unwrap();
1288                         for var in e.variants.iter() {
1289                                 write!(w, "\t\t\t{}{}::{} ", if $to_c { "native" } else { "" }, e.ident, var.ident).unwrap();
1290                                 let mut empty_tuple_variant = false;
1291                                 if let syn::Fields::Named(fields) = &var.fields {
1292                                         write!(w, "{{").unwrap();
1293                                         for field in fields.named.iter() {
1294                                                 if export_status(&field.attrs) == ExportStatus::TestOnly { continue; }
1295                                                 write!(w, "{}{}, ", if $ref { "ref " } else { "mut " }, field.ident.as_ref().unwrap()).unwrap();
1296                                         }
1297                                         write!(w, "}} ").unwrap();
1298                                 } else if let syn::Fields::Unnamed(fields) = &var.fields {
1299                                         if fields.unnamed.len() == 1 {
1300                                                 let mut empty_check = Vec::new();
1301                                                 types.write_c_type(&mut empty_check, &fields.unnamed[0].ty, Some(&gen_types), false);
1302                                                 if empty_check.is_empty() {
1303                                                         empty_tuple_variant = true;
1304                                                 }
1305                                         }
1306                                         if !empty_tuple_variant || $to_c {
1307                                                 write!(w, "(").unwrap();
1308                                                 for (idx, field) in fields.unnamed.iter().enumerate() {
1309                                                         if export_status(&field.attrs) == ExportStatus::TestOnly { continue; }
1310                                                         write!(w, "{}{}, ", if $ref { "ref " } else { "mut " }, ('a' as u8 + idx as u8) as char).unwrap();
1311                                                 }
1312                                                 write!(w, ") ").unwrap();
1313                                         }
1314                                 }
1315                                 write!(w, "=>").unwrap();
1316
1317                                 macro_rules! handle_field_a {
1318                                         ($field: expr, $field_ident: expr) => { {
1319                                                 if export_status(&$field.attrs) == ExportStatus::TestOnly { continue; }
1320                                                 let mut sink = ::std::io::sink();
1321                                                 let mut out: &mut dyn std::io::Write = if $ref { &mut sink } else { w };
1322                                                 let new_var = if $to_c {
1323                                                         types.write_to_c_conversion_new_var(&mut out, $field_ident, &$field.ty, Some(&gen_types), false)
1324                                                 } else {
1325                                                         types.write_from_c_conversion_new_var(&mut out, $field_ident, &$field.ty, Some(&gen_types))
1326                                                 };
1327                                                 if $ref || new_var {
1328                                                         if $ref {
1329                                                                 write!(w, "let mut {}_nonref = (*{}).clone();\n\t\t\t\t", $field_ident, $field_ident).unwrap();
1330                                                                 if new_var {
1331                                                                         let nonref_ident = format_ident!("{}_nonref", $field_ident);
1332                                                                         if $to_c {
1333                                                                                 types.write_to_c_conversion_new_var(w, &nonref_ident, &$field.ty, Some(&gen_types), false);
1334                                                                         } else {
1335                                                                                 types.write_from_c_conversion_new_var(w, &nonref_ident, &$field.ty, Some(&gen_types));
1336                                                                         }
1337                                                                         write!(w, "\n\t\t\t\t").unwrap();
1338                                                                 }
1339                                                         } else {
1340                                                                 write!(w, "\n\t\t\t\t").unwrap();
1341                                                         }
1342                                                 }
1343                                         } }
1344                                 }
1345                                 if let syn::Fields::Named(fields) = &var.fields {
1346                                         write!(w, " {{\n\t\t\t\t").unwrap();
1347                                         for field in fields.named.iter() {
1348                                                 handle_field_a!(field, field.ident.as_ref().unwrap());
1349                                         }
1350                                 } else if let syn::Fields::Unnamed(fields) = &var.fields {
1351                                         write!(w, " {{\n\t\t\t\t").unwrap();
1352                                         for (idx, field) in fields.unnamed.iter().enumerate() {
1353                                                 if !empty_tuple_variant {
1354                                                         handle_field_a!(field, &format_ident!("{}", ('a' as u8 + idx as u8) as char));
1355                                                 }
1356                                         }
1357                                 } else { write!(w, " ").unwrap(); }
1358
1359                                 write!(w, "{}{}::{}", if $to_c { "" } else { "native" }, e.ident, var.ident).unwrap();
1360
1361                                 macro_rules! handle_field_b {
1362                                         ($field: expr, $field_ident: expr) => { {
1363                                                 if export_status(&$field.attrs) == ExportStatus::TestOnly { continue; }
1364                                                 if $to_c {
1365                                                         types.write_to_c_conversion_inline_prefix(w, &$field.ty, Some(&gen_types), false);
1366                                                 } else {
1367                                                         types.write_from_c_conversion_prefix(w, &$field.ty, Some(&gen_types));
1368                                                 }
1369                                                 write!(w, "{}{}", $field_ident,
1370                                                         if $ref { "_nonref" } else { "" }).unwrap();
1371                                                 if $to_c {
1372                                                         types.write_to_c_conversion_inline_suffix(w, &$field.ty, Some(&gen_types), false);
1373                                                 } else {
1374                                                         types.write_from_c_conversion_suffix(w, &$field.ty, Some(&gen_types));
1375                                                 }
1376                                                 write!(w, ",").unwrap();
1377                                         } }
1378                                 }
1379
1380                                 if let syn::Fields::Named(fields) = &var.fields {
1381                                         write!(w, " {{").unwrap();
1382                                         for field in fields.named.iter() {
1383                                                 if export_status(&field.attrs) == ExportStatus::TestOnly { continue; }
1384                                                 write!(w, "\n\t\t\t\t\t{}: ", field.ident.as_ref().unwrap()).unwrap();
1385                                                 handle_field_b!(field, field.ident.as_ref().unwrap());
1386                                         }
1387                                         writeln!(w, "\n\t\t\t\t}}").unwrap();
1388                                         write!(w, "\t\t\t}}").unwrap();
1389                                 } else if let syn::Fields::Unnamed(fields) = &var.fields {
1390                                         if !empty_tuple_variant || !$to_c {
1391                                                 write!(w, " (").unwrap();
1392                                                 for (idx, field) in fields.unnamed.iter().enumerate() {
1393                                                         write!(w, "\n\t\t\t\t\t").unwrap();
1394                                                         handle_field_b!(field, &format_ident!("{}", ('a' as u8 + idx as u8) as char));
1395                                                 }
1396                                                 writeln!(w, "\n\t\t\t\t)").unwrap();
1397                                         }
1398                                         write!(w, "\t\t\t}}").unwrap();
1399                                 }
1400                                 writeln!(w, ",").unwrap();
1401                         }
1402                         writeln!(w, "\t\t}}\n\t}}").unwrap();
1403                 }
1404         }
1405
1406         write_conv!(format!("to_native(&self) -> native{}", e.ident), false, true);
1407         write_conv!(format!("into_native(self) -> native{}", e.ident), false, false);
1408         write_conv!(format!("from_native(native: &native{}) -> Self", e.ident), true, true);
1409         write_conv!(format!("native_into(native: native{}) -> Self", e.ident), true, false);
1410         writeln!(w, "}}").unwrap();
1411
1412         if needs_free {
1413                 writeln!(w, "/// Frees any resources used by the {}", e.ident).unwrap();
1414                 writeln!(w, "#[no_mangle]\npub extern \"C\" fn {}_free(this_ptr: {}) {{ }}", e.ident, e.ident).unwrap();
1415         }
1416         writeln!(w, "/// Creates a copy of the {}", e.ident).unwrap();
1417         writeln!(w, "#[no_mangle]").unwrap();
1418         writeln!(w, "pub extern \"C\" fn {}_clone(orig: &{}) -> {} {{", e.ident, e.ident, e.ident).unwrap();
1419         writeln!(w, "\torig.clone()").unwrap();
1420         writeln!(w, "}}").unwrap();
1421         w.write_all(&constr).unwrap();
1422         write_cpp_wrapper(cpp_headers, &format!("{}", e.ident), needs_free, None);
1423 }
1424
1425 fn writeln_fn<'a, 'b, W: std::io::Write>(w: &mut W, f: &'a syn::ItemFn, types: &mut TypeResolver<'b, 'a>) {
1426         match export_status(&f.attrs) {
1427                 ExportStatus::Export => {},
1428                 ExportStatus::NoExport|ExportStatus::TestOnly => return,
1429                 ExportStatus::NotImplementable => panic!("(C-not implementable) must only appear on traits"),
1430         }
1431         let mut gen_types = GenericTypes::new(None);
1432         if !gen_types.learn_generics(&f.sig.generics, types) { return; }
1433
1434         writeln_fn_docs(w, &f.attrs, "", types, Some(&gen_types), f.sig.inputs.iter(), &f.sig.output);
1435
1436         write!(w, "#[no_mangle]\npub extern \"C\" fn {}(", f.sig.ident).unwrap();
1437         write_method_params(w, &f.sig, "", types, Some(&gen_types), false, true);
1438         write!(w, " {{\n\t").unwrap();
1439         write_method_var_decl_body(w, &f.sig, "", types, Some(&gen_types), false);
1440         write!(w, "{}::{}(", types.module_path, f.sig.ident).unwrap();
1441         write_method_call_params(w, &f.sig, "", types, Some(&gen_types), "", false);
1442         writeln!(w, "\n}}\n").unwrap();
1443 }
1444
1445 // ********************************
1446 // *** File/Crate Walking Logic ***
1447 // ********************************
1448
1449 fn convert_priv_mod<'a, 'b: 'a, W: std::io::Write>(w: &mut W, libast: &'b FullLibraryAST, crate_types: &CrateTypes<'b>, out_dir: &str, mod_path: &str, module: &'b syn::ItemMod) {
1450         // We want to ignore all items declared in this module (as they are not pub), but we still need
1451         // to give the ImportResolver any use statements, so we copy them here.
1452         let mut use_items = Vec::new();
1453         for item in module.content.as_ref().unwrap().1.iter() {
1454                 if let syn::Item::Use(_) = item {
1455                         use_items.push(item);
1456                 }
1457         }
1458         let import_resolver = ImportResolver::from_borrowed_items(mod_path.splitn(2, "::").next().unwrap(), &libast.dependencies, mod_path, &use_items);
1459         let mut types = TypeResolver::new(mod_path, import_resolver, crate_types);
1460
1461         writeln!(w, "mod {} {{\n{}", module.ident, DEFAULT_IMPORTS).unwrap();
1462         for item in module.content.as_ref().unwrap().1.iter() {
1463                 match item {
1464                         syn::Item::Mod(m) => convert_priv_mod(w, libast, crate_types, out_dir, &format!("{}::{}", mod_path, module.ident), m),
1465                         syn::Item::Impl(i) => {
1466                                 if let &syn::Type::Path(ref p) = &*i.self_ty {
1467                                         if p.path.get_ident().is_some() {
1468                                                 writeln_impl(w, i, &mut types);
1469                                         }
1470                                 }
1471                         },
1472                         _ => {},
1473                 }
1474         }
1475         writeln!(w, "}}").unwrap();
1476 }
1477
1478 /// Do the Real Work of mapping an original file to C-callable wrappers. Creates a new file at
1479 /// `out_path` and fills it with wrapper structs/functions to allow calling the things in the AST
1480 /// at `module` from C.
1481 fn convert_file<'a, 'b>(libast: &'a FullLibraryAST, crate_types: &CrateTypes<'a>, out_dir: &str, header_file: &mut File, cpp_header_file: &mut File) {
1482         for (module, astmod) in libast.modules.iter() {
1483                 let orig_crate = module.splitn(2, "::").next().unwrap();
1484                 let ASTModule { ref attrs, ref items, ref submods } = astmod;
1485                 assert_eq!(export_status(&attrs), ExportStatus::Export);
1486
1487                 let new_file_path = if submods.is_empty() {
1488                         format!("{}/{}.rs", out_dir, module.replace("::", "/"))
1489                 } else if module != "" {
1490                         format!("{}/{}/mod.rs", out_dir, module.replace("::", "/"))
1491                 } else {
1492                         format!("{}/lib.rs", out_dir)
1493                 };
1494                 let _ = std::fs::create_dir((&new_file_path.as_ref() as &std::path::Path).parent().unwrap());
1495                 let mut out = std::fs::OpenOptions::new().write(true).create(true).truncate(true)
1496                         .open(new_file_path).expect("Unable to open new src file");
1497
1498                 writeln!(out, "// This file is Copyright its original authors, visible in version control").unwrap();
1499                 writeln!(out, "// history and in the source files from which this was generated.").unwrap();
1500                 writeln!(out, "//").unwrap();
1501                 writeln!(out, "// This file is licensed under the license available in the LICENSE or LICENSE.md").unwrap();
1502                 writeln!(out, "// file in the root of this repository or, if no such file exists, the same").unwrap();
1503                 writeln!(out, "// license as that which applies to the original source files from which this").unwrap();
1504                 writeln!(out, "// source was automatically generated.").unwrap();
1505                 writeln!(out, "").unwrap();
1506
1507                 writeln_docs(&mut out, &attrs, "");
1508
1509                 if module == "" {
1510                         // Special-case the top-level lib.rs with various lint allows and a pointer to the c_types
1511                         // and bitcoin hand-written modules.
1512                         writeln!(out, "//! C Bindings").unwrap();
1513                         writeln!(out, "#![allow(unknown_lints)]").unwrap();
1514                         writeln!(out, "#![allow(non_camel_case_types)]").unwrap();
1515                         writeln!(out, "#![allow(non_snake_case)]").unwrap();
1516                         writeln!(out, "#![allow(unused_imports)]").unwrap();
1517                         writeln!(out, "#![allow(unused_variables)]").unwrap();
1518                         writeln!(out, "#![allow(unused_mut)]").unwrap();
1519                         writeln!(out, "#![allow(unused_parens)]").unwrap();
1520                         writeln!(out, "#![allow(unused_unsafe)]").unwrap();
1521                         writeln!(out, "#![allow(unused_braces)]").unwrap();
1522                         // TODO: We need to map deny(missing_docs) in the source crate(s)
1523                         //writeln!(out, "#![deny(missing_docs)]").unwrap();
1524                         writeln!(out, "pub mod version;").unwrap();
1525                         writeln!(out, "pub mod c_types;").unwrap();
1526                         writeln!(out, "pub mod bitcoin;").unwrap();
1527                 } else {
1528                         writeln!(out, "{}", DEFAULT_IMPORTS).unwrap();
1529                 }
1530
1531                 for m in submods {
1532                         writeln!(out, "pub mod {};", m).unwrap();
1533                 }
1534
1535                 eprintln!("Converting {} entries...", module);
1536
1537                 let import_resolver = ImportResolver::new(orig_crate, &libast.dependencies, module, items);
1538                 let mut type_resolver = TypeResolver::new(module, import_resolver, crate_types);
1539
1540                 for item in items.iter() {
1541                         match item {
1542                                 syn::Item::Use(_) => {}, // Handled above
1543                                 syn::Item::Static(_) => {},
1544                                 syn::Item::Enum(e) => {
1545                                         if let syn::Visibility::Public(_) = e.vis {
1546                                                 writeln_enum(&mut out, &e, &mut type_resolver, header_file, cpp_header_file);
1547                                         }
1548                                 },
1549                                 syn::Item::Impl(i) => {
1550                                         writeln_impl(&mut out, &i, &mut type_resolver);
1551                                 },
1552                                 syn::Item::Struct(s) => {
1553                                         if let syn::Visibility::Public(_) = s.vis {
1554                                                 writeln_struct(&mut out, &s, &mut type_resolver, header_file, cpp_header_file);
1555                                         }
1556                                 },
1557                                 syn::Item::Trait(t) => {
1558                                         if let syn::Visibility::Public(_) = t.vis {
1559                                                 writeln_trait(&mut out, &t, &mut type_resolver, header_file, cpp_header_file);
1560                                         }
1561                                 },
1562                                 syn::Item::Mod(m) => {
1563                                         convert_priv_mod(&mut out, libast, crate_types, out_dir, &format!("{}::{}", module, m.ident), m);
1564                                 },
1565                                 syn::Item::Const(c) => {
1566                                         // Re-export any primitive-type constants.
1567                                         if let syn::Visibility::Public(_) = c.vis {
1568                                                 if let syn::Type::Path(p) = &*c.ty {
1569                                                         let resolved_path = type_resolver.resolve_path(&p.path, None);
1570                                                         if type_resolver.is_primitive(&resolved_path) {
1571                                                                 writeln_field_docs(&mut out, &c.attrs, "", &mut type_resolver, None, &*c.ty);
1572                                                                 writeln!(out, "\n#[no_mangle]").unwrap();
1573                                                                 writeln!(out, "pub static {}: {} = {}::{};", c.ident, resolved_path, module, c.ident).unwrap();
1574                                                         }
1575                                                 }
1576                                         }
1577                                 },
1578                                 syn::Item::Type(t) => {
1579                                         if let syn::Visibility::Public(_) = t.vis {
1580                                                 match export_status(&t.attrs) {
1581                                                         ExportStatus::Export => {},
1582                                                         ExportStatus::NoExport|ExportStatus::TestOnly => continue,
1583                                                         ExportStatus::NotImplementable => panic!("(C-not implementable) must only appear on traits"),
1584                                                 }
1585
1586                                                 let mut process_alias = true;
1587                                                 for tok in t.generics.params.iter() {
1588                                                         if let syn::GenericParam::Lifetime(_) = tok {}
1589                                                         else { process_alias = false; }
1590                                                 }
1591                                                 if process_alias {
1592                                                         match &*t.ty {
1593                                                                 syn::Type::Path(_) =>
1594                                                                         writeln_opaque(&mut out, &t.ident, &format!("{}", t.ident), &t.generics, &t.attrs, &type_resolver, header_file, cpp_header_file),
1595                                                                 _ => {}
1596                                                         }
1597                                                 }
1598                                         }
1599                                 },
1600                                 syn::Item::Fn(f) => {
1601                                         if let syn::Visibility::Public(_) = f.vis {
1602                                                 writeln_fn(&mut out, &f, &mut type_resolver);
1603                                         }
1604                                 },
1605                                 syn::Item::Macro(_) => {},
1606                                 syn::Item::Verbatim(_) => {},
1607                                 syn::Item::ExternCrate(_) => {},
1608                                 _ => unimplemented!(),
1609                         }
1610                 }
1611
1612                 out.flush().unwrap();
1613         }
1614 }
1615
1616 fn walk_private_mod<'a>(ast_storage: &'a FullLibraryAST, orig_crate: &str, module: String, items: &'a syn::ItemMod, crate_types: &mut CrateTypes<'a>) {
1617         let import_resolver = ImportResolver::new(orig_crate, &ast_storage.dependencies, &module, &items.content.as_ref().unwrap().1);
1618         for item in items.content.as_ref().unwrap().1.iter() {
1619                 match item {
1620                         syn::Item::Mod(m) => walk_private_mod(ast_storage, orig_crate, format!("{}::{}", module, m.ident), m, crate_types),
1621                         syn::Item::Impl(i) => {
1622                                 if let &syn::Type::Path(ref p) = &*i.self_ty {
1623                                         if let Some(trait_path) = i.trait_.as_ref() {
1624                                                 if let Some(tp) = import_resolver.maybe_resolve_path(&trait_path.1, None) {
1625                                                         if let Some(sp) = import_resolver.maybe_resolve_path(&p.path, None) {
1626                                                                 match crate_types.trait_impls.entry(sp) {
1627                                                                         hash_map::Entry::Occupied(mut e) => { e.get_mut().push(tp); },
1628                                                                         hash_map::Entry::Vacant(e) => { e.insert(vec![tp]); },
1629                                                                 }
1630                                                         }
1631                                                 }
1632                                         }
1633                                 }
1634                         },
1635                         _ => {},
1636                 }
1637         }
1638 }
1639
1640 /// Walk the FullLibraryAST, deciding how things will be mapped and adding tracking to CrateTypes.
1641 fn walk_ast<'a>(ast_storage: &'a FullLibraryAST, crate_types: &mut CrateTypes<'a>) {
1642         for (module, astmod) in ast_storage.modules.iter() {
1643                 let ASTModule { ref attrs, ref items, submods: _ } = astmod;
1644                 assert_eq!(export_status(&attrs), ExportStatus::Export);
1645                 let orig_crate = module.splitn(2, "::").next().unwrap();
1646                 let import_resolver = ImportResolver::new(orig_crate, &ast_storage.dependencies, module, items);
1647
1648                 for item in items.iter() {
1649                         match item {
1650                                 syn::Item::Struct(s) => {
1651                                         if let syn::Visibility::Public(_) = s.vis {
1652                                                 match export_status(&s.attrs) {
1653                                                         ExportStatus::Export => {},
1654                                                         ExportStatus::NoExport|ExportStatus::TestOnly => continue,
1655                                                         ExportStatus::NotImplementable => panic!("(C-not implementable) must only appear on traits"),
1656                                                 }
1657                                                 let struct_path = format!("{}::{}", module, s.ident);
1658                                                 crate_types.opaques.insert(struct_path, &s.ident);
1659                                         }
1660                                 },
1661                                 syn::Item::Trait(t) => {
1662                                         if let syn::Visibility::Public(_) = t.vis {
1663                                                 match export_status(&t.attrs) {
1664                                                         ExportStatus::Export|ExportStatus::NotImplementable => {},
1665                                                         ExportStatus::NoExport|ExportStatus::TestOnly => continue,
1666                                                 }
1667                                                 let trait_path = format!("{}::{}", module, t.ident);
1668                                                 walk_supertraits!(t, None, (
1669                                                         ("Clone", _) => {
1670                                                                 crate_types.set_clonable("crate::".to_owned() + &trait_path);
1671                                                         },
1672                                                         (_, _) => {}
1673                                                 ) );
1674                                                 crate_types.traits.insert(trait_path, &t);
1675                                         }
1676                                 },
1677                                 syn::Item::Type(t) => {
1678                                         if let syn::Visibility::Public(_) = t.vis {
1679                                                 match export_status(&t.attrs) {
1680                                                         ExportStatus::Export => {},
1681                                                         ExportStatus::NoExport|ExportStatus::TestOnly => continue,
1682                                                         ExportStatus::NotImplementable => panic!("(C-not implementable) must only appear on traits"),
1683                                                 }
1684                                                 let type_path = format!("{}::{}", module, t.ident);
1685                                                 let mut process_alias = true;
1686                                                 for tok in t.generics.params.iter() {
1687                                                         if let syn::GenericParam::Lifetime(_) = tok {}
1688                                                         else { process_alias = false; }
1689                                                 }
1690                                                 if process_alias {
1691                                                         match &*t.ty {
1692                                                                 syn::Type::Path(p) => {
1693                                                                         let t_ident = &t.ident;
1694
1695                                                                         // If its a path with no generics, assume we don't map the aliased type and map it opaque
1696                                                                         let path_obj = parse_quote!(#t_ident);
1697                                                                         let args_obj = p.path.segments.last().unwrap().arguments.clone();
1698                                                                         match crate_types.reverse_alias_map.entry(import_resolver.maybe_resolve_path(&p.path, None).unwrap()) {
1699                                                                                 hash_map::Entry::Occupied(mut e) => { e.get_mut().push((path_obj, args_obj)); },
1700                                                                                 hash_map::Entry::Vacant(e) => { e.insert(vec![(path_obj, args_obj)]); },
1701                                                                         }
1702
1703                                                                         crate_types.opaques.insert(type_path, t_ident);
1704                                                                 },
1705                                                                 _ => {
1706                                                                         crate_types.type_aliases.insert(type_path, import_resolver.resolve_imported_refs((*t.ty).clone()));
1707                                                                 }
1708                                                         }
1709                                                 }
1710                                         }
1711                                 },
1712                                 syn::Item::Enum(e) if is_enum_opaque(e) => {
1713                                         if let syn::Visibility::Public(_) = e.vis {
1714                                                 match export_status(&e.attrs) {
1715                                                         ExportStatus::Export => {},
1716                                                         ExportStatus::NoExport|ExportStatus::TestOnly => continue,
1717                                                         ExportStatus::NotImplementable => panic!("(C-not implementable) must only appear on traits"),
1718                                                 }
1719                                                 let enum_path = format!("{}::{}", module, e.ident);
1720                                                 crate_types.opaques.insert(enum_path, &e.ident);
1721                                         }
1722                                 },
1723                                 syn::Item::Enum(e) => {
1724                                         if let syn::Visibility::Public(_) = e.vis {
1725                                                 match export_status(&e.attrs) {
1726                                                         ExportStatus::Export => {},
1727                                                         ExportStatus::NoExport|ExportStatus::TestOnly => continue,
1728                                                         ExportStatus::NotImplementable => panic!("(C-not implementable) must only appear on traits"),
1729                                                 }
1730                                                 let enum_path = format!("{}::{}", module, e.ident);
1731                                                 crate_types.mirrored_enums.insert(enum_path, &e);
1732                                         }
1733                                 },
1734                                 syn::Item::Impl(i) => {
1735                                         if let &syn::Type::Path(ref p) = &*i.self_ty {
1736                                                 if let Some(trait_path) = i.trait_.as_ref() {
1737                                                         if path_matches_nongeneric(&trait_path.1, &["core", "clone", "Clone"]) {
1738                                                                 if let Some(full_path) = import_resolver.maybe_resolve_path(&p.path, None) {
1739                                                                         crate_types.set_clonable("crate::".to_owned() + &full_path);
1740                                                                 }
1741                                                         }
1742                                                         if let Some(tp) = import_resolver.maybe_resolve_path(&trait_path.1, None) {
1743                                                                 if let Some(sp) = import_resolver.maybe_resolve_path(&p.path, None) {
1744                                                                         match crate_types.trait_impls.entry(sp) {
1745                                                                                 hash_map::Entry::Occupied(mut e) => { e.get_mut().push(tp); },
1746                                                                                 hash_map::Entry::Vacant(e) => { e.insert(vec![tp]); },
1747                                                                         }
1748                                                                 }
1749                                                         }
1750                                                 }
1751                                         }
1752                                 },
1753                                 syn::Item::Mod(m) => walk_private_mod(ast_storage, orig_crate, format!("{}::{}", module, m.ident), m, crate_types),
1754                                 _ => {},
1755                         }
1756                 }
1757         }
1758 }
1759
1760 fn main() {
1761         let args: Vec<String> = env::args().collect();
1762         if args.len() != 5 {
1763                 eprintln!("Usage: target/dir derived_templates.rs extra/includes.h extra/cpp/includes.hpp");
1764                 process::exit(1);
1765         }
1766
1767         let mut derived_templates = std::fs::OpenOptions::new().write(true).create(true).truncate(true)
1768                 .open(&args[2]).expect("Unable to open new header file");
1769         let mut header_file = std::fs::OpenOptions::new().write(true).create(true).truncate(true)
1770                 .open(&args[3]).expect("Unable to open new header file");
1771         let mut cpp_header_file = std::fs::OpenOptions::new().write(true).create(true).truncate(true)
1772                 .open(&args[4]).expect("Unable to open new header file");
1773
1774         writeln!(header_file, "#if defined(__GNUC__)").unwrap();
1775         writeln!(header_file, "#define MUST_USE_STRUCT __attribute__((warn_unused))").unwrap();
1776         writeln!(header_file, "#define MUST_USE_RES __attribute__((warn_unused_result))").unwrap();
1777         writeln!(header_file, "#else").unwrap();
1778         writeln!(header_file, "#define MUST_USE_STRUCT").unwrap();
1779         writeln!(header_file, "#define MUST_USE_RES").unwrap();
1780         writeln!(header_file, "#endif").unwrap();
1781         writeln!(header_file, "#if defined(__clang__)").unwrap();
1782         writeln!(header_file, "#define NONNULL_PTR _Nonnull").unwrap();
1783         writeln!(header_file, "#else").unwrap();
1784         writeln!(header_file, "#define NONNULL_PTR").unwrap();
1785         writeln!(header_file, "#endif").unwrap();
1786         writeln!(cpp_header_file, "#include <string.h>\nnamespace LDK {{").unwrap();
1787
1788         // First parse the full crate's ASTs, caching them so that we can hold references to the AST
1789         // objects in other datastructures:
1790         let mut lib_src = String::new();
1791         std::io::stdin().lock().read_to_string(&mut lib_src).unwrap();
1792         let lib_syntax = syn::parse_file(&lib_src).expect("Unable to parse file");
1793         let libast = FullLibraryAST::load_lib(lib_syntax);
1794
1795         // ...then walk the ASTs tracking what types we will map, and how, so that we can resolve them
1796         // when parsing other file ASTs...
1797         let mut libtypes = CrateTypes::new(&mut derived_templates, &libast);
1798         walk_ast(&libast, &mut libtypes);
1799
1800         // ... finally, do the actual file conversion/mapping, writing out types as we go.
1801         convert_file(&libast, &libtypes, &args[1], &mut header_file, &mut cpp_header_file);
1802
1803         // For container templates which we created while walking the crate, make sure we add C++
1804         // mapped types so that C++ users can utilize the auto-destructors available.
1805         for (ty, has_destructor) in libtypes.templates_defined.borrow().iter() {
1806                 write_cpp_wrapper(&mut cpp_header_file, ty, *has_destructor, None);
1807         }
1808         writeln!(cpp_header_file, "}}").unwrap();
1809
1810         header_file.flush().unwrap();
1811         cpp_header_file.flush().unwrap();
1812         derived_templates.flush().unwrap();
1813 }