_ 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, HashSet};
  22 use std::env;
  23 use std::fs::File;
  24 use std::io::{Read, Write};
  25 use std::iter::FromIterator;
  26 use std::process;
  27
  28 use proc_macro2::Span;
  29 use quote::format_ident;
  30 use syn::parse_quote;
  31
  32 mod types;
  33 mod blocks;
  34 use types::*;
  35 use blocks::*;
  36
  37 const DEFAULT_IMPORTS: &'static str = "
  38 use alloc::str::FromStr;
  39 use core::ffi::c_void;
  40 use core::convert::Infallible;
  41 use bitcoin::hashes::Hash;
  42 use crate::c_types::*;
  43 #[cfg(feature=\"no-std\")]
  44 use alloc::{vec::Vec, boxed::Box};
  45 ";
  46
  47
  48 /// str.rsplit_once but with an older MSRV
  49 fn rsplit_once<'a>(inp: &'a str, pattern: &str) -> Option<(&'a str, &'a str)> {
  50         let mut iter = inp.rsplitn(2, pattern);
  51         let second_entry = iter.next().unwrap();
  52         Some((iter.next().unwrap(), second_entry))
  53 }
  54
  55 // *************************************
  56 // *** Manually-expanded conversions ***
  57 // *************************************
  58
  59 /// Convert "impl trait_path for for_ty { .. }" for manually-mapped types (ie (de)serialization)
  60 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) {
  61         if let Some(t) = types.maybe_resolve_path(&trait_path, Some(generics)) {
  62                 let for_obj;
  63                 let full_obj_path;
  64                 let mut has_inner = false;
  65                 if let syn::Type::Path(ref p) = for_ty {
  66                         let resolved_path = types.resolve_path(&p.path, Some(generics));
  67                         for_obj = format!("{}", p.path.segments.last().unwrap().ident);
  68                         full_obj_path = format!("crate::{}", resolved_path);
  69                         has_inner = types.c_type_has_inner_from_path(&resolved_path);
  70                 } else {
  71                         // We assume that anything that isn't a Path is somehow a generic that ends up in our
  72                         // derived-types module.
  73                         let mut for_obj_vec = Vec::new();
  74                         types.write_c_type(&mut for_obj_vec, for_ty, Some(generics), false);
  75                         full_obj_path = String::from_utf8(for_obj_vec).unwrap();
  76                         assert!(full_obj_path.starts_with(TypeResolver::generated_container_path()));
  77                         for_obj = full_obj_path[TypeResolver::generated_container_path().len() + 2..].into();
  78                 }
  79
  80                 match &t as &str {
  81                         "lightning::util::ser::Writeable" => {
  82                                 writeln!(w, "#[no_mangle]").unwrap();
  83                                 writeln!(w, "/// Serialize the {} object into a byte array which can be read by {}_read", for_obj, for_obj).unwrap();
  84                                 writeln!(w, "pub extern \"C\" fn {}_write(obj: &{}) -> crate::c_types::derived::CVec_u8Z {{", for_obj, full_obj_path).unwrap();
  85
  86                                 let ref_type: syn::Type = syn::parse_quote!(&#for_ty);
  87                                 assert!(!types.write_from_c_conversion_new_var(w, &format_ident!("obj"), &ref_type, Some(generics)));
  88
  89                                 write!(w, "\tcrate::c_types::serialize_obj(").unwrap();
  90                                 types.write_from_c_conversion_prefix(w, &ref_type, Some(generics));
  91                                 write!(w, "unsafe {{ &*obj }}").unwrap();
  92                                 types.write_from_c_conversion_suffix(w, &ref_type, Some(generics));
  93                                 writeln!(w, ")").unwrap();
  94
  95                                 writeln!(w, "}}").unwrap();
  96                                 if has_inner {
  97                                         writeln!(w, "#[no_mangle]").unwrap();
  98                                         writeln!(w, "pub(crate) extern \"C\" fn {}_write_void(obj: *const c_void) -> crate::c_types::derived::CVec_u8Z {{", for_obj).unwrap();
  99                                         writeln!(w, "\tcrate::c_types::serialize_obj(unsafe {{ &*(obj as *const native{}) }})", for_obj).unwrap();
 100                                         writeln!(w, "}}").unwrap();
 101                                 }
 102                         },
 103                         "lightning::util::ser::Readable"|"lightning::util::ser::ReadableArgs"|"lightning::util::ser::MaybeReadable" => {
 104                                 // Create the Result<Object, DecodeError> syn::Type
 105                                 let mut res_ty: syn::Type = parse_quote!(Result<#for_ty, lightning::ln::msgs::DecodeError>);
 106
 107                                 writeln!(w, "#[no_mangle]").unwrap();
 108                                 writeln!(w, "/// Read a {} from a byte array, created by {}_write", for_obj, for_obj).unwrap();
 109                                 write!(w, "pub extern \"C\" fn {}_read(ser: crate::c_types::u8slice", for_obj).unwrap();
 110
 111                                 let mut arg_conv = Vec::new();
 112                                 if t == "lightning::util::ser::ReadableArgs" {
 113                                         assert!(trait_path.leading_colon.is_none());
 114                                         let args_seg = trait_path.segments.iter().last().unwrap();
 115                                         assert_eq!(format!("{}", args_seg.ident), "ReadableArgs");
 116                                         if let syn::PathArguments::AngleBracketed(args) = &args_seg.arguments {
 117                                                 assert_eq!(args.args.len(), 1);
 118                                                 if let syn::GenericArgument::Type(args_ty) = args.args.iter().next().unwrap() {
 119                                                         macro_rules! write_arg_conv {
 120                                                                 ($ty: expr, $arg_name: expr) => {
 121                                                                         write!(w, ", {}: ", $arg_name).unwrap();
 122                                                                         types.write_c_type(w, $ty, Some(generics), false);
 123
 124                                                                         write!(&mut arg_conv, "\t").unwrap();
 125                                                                         if types.write_from_c_conversion_new_var(&mut arg_conv, &format_ident!("{}", $arg_name), &$ty, Some(generics)) {
 126                                                                                 write!(&mut arg_conv, "\n\t").unwrap();
 127                                                                         }
 128
 129                                                                         write!(&mut arg_conv, "let {}_conv = ", $arg_name).unwrap();
 130                                                                         types.write_from_c_conversion_prefix(&mut arg_conv, &$ty, Some(generics));
 131                                                                         write!(&mut arg_conv, "{}", $arg_name).unwrap();
 132                                                                         types.write_from_c_conversion_suffix(&mut arg_conv, &$ty, Some(generics));
 133                                                                         write!(&mut arg_conv, ";\n").unwrap();
 134                                                                 }
 135                                                         }
 136
 137                                                         if let syn::Type::Tuple(tup) = args_ty {
 138                                                                 // Crack open tuples and make them separate arguments instead of
 139                                                                 // converting the full tuple. This makes it substantially easier to
 140                                                                 // reason about things like references in the tuple fields.
 141                                                                 let mut arg_conv_res = Vec::new();
 142                                                                 for (idx, elem) in tup.elems.iter().enumerate() {
 143                                                                         let arg_name = format!("arg_{}", ('a' as u8 + idx as u8) as char);
 144                                                                         write_arg_conv!(elem, arg_name);
 145                                                                         write!(&mut arg_conv_res, "{}_conv{}", arg_name, if idx != tup.elems.len() - 1 { ", " } else { "" }).unwrap();
 146                                                                 }
 147                                                                 writeln!(&mut arg_conv, "\tlet arg_conv = ({});", String::from_utf8(arg_conv_res).unwrap()).unwrap();
 148                                                         } else {
 149                                                                 write_arg_conv!(args_ty, "arg");
 150                                                         }
 151                                                 } else { unreachable!(); }
 152                                         } else { unreachable!(); }
 153                                 } else if t == "lightning::util::ser::MaybeReadable" {
 154                                         res_ty = parse_quote!(Result<Option<#for_ty>, lightning::ln::msgs::DecodeError>);
 155                                 }
 156                                 write!(w, ") -> ").unwrap();
 157                                 types.write_c_type(w, &res_ty, Some(generics), false);
 158                                 writeln!(w, " {{").unwrap();
 159
 160                                 if t == "lightning::util::ser::ReadableArgs" {
 161                                         w.write(&arg_conv).unwrap();
 162                                 }
 163
 164                                 write!(w, "\tlet res: ").unwrap();
 165                                 // At least in one case we need type annotations here, so provide them.
 166                                 types.write_rust_type(w, Some(generics), &res_ty, false);
 167
 168                                 if t == "lightning::util::ser::ReadableArgs" {
 169                                         writeln!(w, " = crate::c_types::deserialize_obj_arg(ser, arg_conv);").unwrap();
 170                                 } else if t == "lightning::util::ser::MaybeReadable" {
 171                                         writeln!(w, " = crate::c_types::maybe_deserialize_obj(ser);").unwrap();
 172                                 } else {
 173                                         writeln!(w, " = crate::c_types::deserialize_obj(ser);").unwrap();
 174                                 }
 175                                 write!(w, "\t").unwrap();
 176                                 if types.write_to_c_conversion_new_var(w, &format_ident!("res"), &res_ty, Some(generics), false) {
 177                                         write!(w, "\n\t").unwrap();
 178                                 }
 179                                 types.write_to_c_conversion_inline_prefix(w, &res_ty, Some(generics), false);
 180                                 write!(w, "res").unwrap();
 181                                 types.write_to_c_conversion_inline_suffix(w, &res_ty, Some(generics), false);
 182                                 writeln!(w, "\n}}").unwrap();
 183                         },
 184                         _ => {},
 185                 }
 186         }
 187 }
 188
 189 /// Convert "TraitA : TraitB" to a single function name and return type.
 190 ///
 191 /// This is (obviously) somewhat over-specialized and only useful for TraitB's that only require a
 192 /// single function (eg for serialization).
 193 fn convert_trait_impl_field(trait_path: &str) -> (&'static str, String, &'static str) {
 194         match trait_path {
 195                 "lightning::util::ser::Writeable" => ("Serialize the object into a byte array", "write".to_owned(), "crate::c_types::derived::CVec_u8Z"),
 196                 _ => unimplemented!(),
 197         }
 198 }
 199
 200 /// Companion to convert_trait_impl_field, write an assignment for the function defined by it for
 201 /// `for_obj` which implements the the trait at `trait_path`.
 202 fn write_trait_impl_field_assign<W: std::io::Write>(w: &mut W, trait_path: &str, for_obj: &syn::Ident) {
 203         match trait_path {
 204                 "lightning::util::ser::Writeable" => {
 205                         writeln!(w, "\t\twrite: {}_write_void,", for_obj).unwrap();
 206                 },
 207                 _ => unimplemented!(),
 208         }
 209 }
 210
 211 /// Write out the impl block for a defined trait struct which has a supertrait
 212 fn do_write_impl_trait<W: std::io::Write>(w: &mut W, trait_path: &str, _trait_name: &syn::Ident, for_obj: &str) {
 213         match trait_path {
 214                 "lightning::util::ser::Writeable" => {
 215                         writeln!(w, "impl {} for {} {{", trait_path, for_obj).unwrap();
 216                         writeln!(w, "\tfn write<W: lightning::util::ser::Writer>(&self, w: &mut W) -> Result<(), crate::c_types::io::Error> {{").unwrap();
 217                         writeln!(w, "\t\tlet vec = (self.write)(self.this_arg);").unwrap();
 218                         writeln!(w, "\t\tw.write_all(vec.as_slice())").unwrap();
 219                         writeln!(w, "\t}}\n}}").unwrap();
 220                 },
 221                 _ => panic!(),
 222         }
 223 }
 224
 225 /// Returns true if an instance of the given type must never exist
 226 fn is_type_unconstructable(path: &str) -> bool {
 227         path == "core::convert::Infallible" || path == "crate::c_types::NotConstructable"
 228 }
 229
 230 // *******************************
 231 // *** Per-Type Printing Logic ***
 232 // *******************************
 233
 234 macro_rules! walk_supertraits { ($t: expr, $types: expr, ($( $($pat: pat)|* => $e: expr),*) ) => { {
 235         if $t.colon_token.is_some() {
 236                 for st in $t.supertraits.iter() {
 237                         match st {
 238                                 syn::TypeParamBound::Trait(supertrait) => {
 239                                         if supertrait.paren_token.is_some() || supertrait.lifetimes.is_some() {
 240                                                 unimplemented!();
 241                                         }
 242                                         // First try to resolve path to find in-crate traits, but if that doesn't work
 243                                         // assume its a prelude trait (eg Clone, etc) and just use the single ident.
 244                                         let types_opt: Option<&TypeResolver> = $types;
 245                                         if let Some(types) = types_opt {
 246                                                 if let Some(path) = types.maybe_resolve_path(&supertrait.path, None) {
 247                                                         let last_seg = supertrait.path.segments.iter().last().unwrap();
 248                                                         match (&path as &str, &last_seg.ident, &last_seg.arguments) {
 249                                                                 $( $($pat)|* => $e, )*
 250                                                         }
 251                                                         continue;
 252                                                 }
 253                                         }
 254                                         if let Some(ident) = supertrait.path.get_ident() {
 255                                                 match (&format!("{}", ident) as &str, &ident, &syn::PathArguments::None) {
 256                                                         $( $($pat)|* => $e, )*
 257                                                 }
 258                                         } else if types_opt.is_some() {
 259                                                 panic!("Supertrait unresolvable and not single-ident");
 260                                         }
 261                                 },
 262                                 syn::TypeParamBound::Lifetime(_) => unimplemented!(),
 263                         }
 264                 }
 265         }
 266 } } }
 267
 268 macro_rules! get_module_type_resolver {
 269         ($module: expr, $crate_libs: expr, $crate_types: expr) => { {
 270                 let module: &str = &$module;
 271                 let mut module_iter = module.rsplitn(2, "::");
 272                 module_iter.next().unwrap();
 273                 let module = module_iter.next().unwrap();
 274                 let imports = ImportResolver::new(module.splitn(2, "::").next().unwrap(), &$crate_types.lib_ast,
 275                                 module, &$crate_types.lib_ast.modules.get(module).unwrap().items);
 276                 TypeResolver::new(module, imports, $crate_types)
 277         } }
 278 }
 279
 280 /// Prints a C-mapped trait object containing a void pointer and a jump table for each function in
 281 /// the original trait.
 282 /// Implements the native Rust trait and relevant parent traits for the new C-mapped trait.
 283 ///
 284 /// Finally, implements Deref<MappedTrait> for MappedTrait which allows its use in types which need
 285 /// a concrete Deref to the Rust trait.
 286 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) {
 287         let trait_name = format!("{}", t.ident);
 288         let implementable;
 289         match export_status(&t.attrs) {
 290                 ExportStatus::Export => { implementable = true; }
 291                 ExportStatus::NotImplementable => { implementable = false; },
 292                 ExportStatus::NoExport|ExportStatus::TestOnly => return,
 293         }
 294         writeln_docs(w, &t.attrs, "");
 295
 296         let mut gen_types = GenericTypes::new(Some(format!("{}::{}", types.module_path, trait_name)));
 297
 298         // Add functions which may be required for supertrait implementations.
 299         // Due to borrow checker limitations, we only support one in-crate supertrait here.
 300         let supertrait_name;
 301         let supertrait_resolver;
 302         walk_supertraits!(t, Some(&types), (
 303                 (s, _i, _) => {
 304                         if let Some(supertrait) = types.crate_types.traits.get(s) {
 305                                 supertrait_name = s.to_string();
 306                                 supertrait_resolver = get_module_type_resolver!(supertrait_name, types.crate_libs, types.crate_types);
 307                                 gen_types.learn_associated_types(&supertrait, &supertrait_resolver);
 308                                 break;
 309                         }
 310                 }
 311         ) );
 312
 313         assert!(gen_types.learn_generics(&t.generics, types));
 314         gen_types.learn_associated_types(&t, types);
 315
 316         writeln!(w, "#[repr(C)]\npub struct {} {{", trait_name).unwrap();
 317         writeln!(w, "\t/// An opaque pointer which is passed to your function implementations as an argument.").unwrap();
 318         writeln!(w, "\t/// This has no meaning in the LDK, and can be NULL or any other value.").unwrap();
 319         writeln!(w, "\tpub this_arg: *mut c_void,").unwrap();
 320         // We store every field's (name, Option<clone_fn>, docs) except this_arg, used in Clone generation
 321         // docs is only set if its a function which should be callable on the object itself in C++
 322         let mut generated_fields = Vec::new();
 323         for item in t.items.iter() {
 324                 match item {
 325                         &syn::TraitItem::Method(ref m) => {
 326                                 match export_status(&m.attrs) {
 327                                         ExportStatus::NoExport => {
 328                                                 // NoExport in this context means we'll hit an unimplemented!() at runtime,
 329                                                 // so bail out.
 330                                                 unimplemented!();
 331                                         },
 332                                         ExportStatus::Export => {},
 333                                         ExportStatus::TestOnly => continue,
 334                                         ExportStatus::NotImplementable => panic!("(C-not implementable) must only appear on traits"),
 335                                 }
 336
 337                                 let mut meth_gen_types = gen_types.push_ctx();
 338                                 assert!(meth_gen_types.learn_generics(&m.sig.generics, types));
 339
 340                                 writeln_fn_docs(w, &m.attrs, "\t", types, Some(&meth_gen_types), m.sig.inputs.iter(), &m.sig.output);
 341
 342                                 if let syn::ReturnType::Type(_, rtype) = &m.sig.output {
 343                                         if let syn::Type::Reference(r) = &**rtype {
 344                                                 // We have to do quite a dance for trait functions which return references
 345                                                 // - they ultimately require us to have a native Rust object stored inside
 346                                                 // our concrete trait to return a reference to. However, users may wish to
 347                                                 // update the value to be returned each time the function is called (or, to
 348                                                 // make C copies of Rust impls equivalent, we have to be able to).
 349                                                 //
 350                                                 // Thus, we store a copy of the C-mapped type (which is just a pointer to
 351                                                 // the Rust type and a flag to indicate whether deallocation needs to
 352                                                 // happen) as well as provide an Option<>al function pointer which is
 353                                                 // called when the trait method is called which allows updating on the fly.
 354                                                 write!(w, "\tpub {}: ", m.sig.ident).unwrap();
 355                                                 generated_fields.push((format!("{}", m.sig.ident), None, None));
 356                                                 types.write_c_type(w, &*r.elem, Some(&meth_gen_types), false);
 357                                                 writeln!(w, ",").unwrap();
 358                                                 writeln!(w, "\t/// Fill in the {} field as a reference to it will be given to Rust after this returns", m.sig.ident).unwrap();
 359                                                 writeln!(w, "\t/// Note that this takes a pointer to this object, not the this_ptr like other methods do").unwrap();
 360                                                 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();
 361                                                 writeln!(w, "\tpub set_{}: Option<extern \"C\" fn(&{})>,", m.sig.ident, trait_name).unwrap();
 362                                                 generated_fields.push((format!("set_{}", m.sig.ident), None, None));
 363                                                 // Note that cbindgen will now generate
 364                                                 // typedef struct Thing {..., set_thing: (const struct Thing*), ...} Thing;
 365                                                 // which does not compile since Thing is not defined before it is used.
 366                                                 writeln!(extra_headers, "struct LDK{};", trait_name).unwrap();
 367                                                 continue;
 368                                         }
 369                                         // Sadly, this currently doesn't do what we want, but it should be easy to get
 370                                         // cbindgen to support it. See https://github.com/eqrion/cbindgen/issues/531
 371                                         writeln!(w, "\t#[must_use]").unwrap();
 372                                 }
 373
 374                                 let mut cpp_docs = Vec::new();
 375                                 writeln_fn_docs(&mut cpp_docs, &m.attrs, "\t * ", types, Some(&meth_gen_types), m.sig.inputs.iter(), &m.sig.output);
 376                                 let docs_string = "\t/**\n".to_owned() + &String::from_utf8(cpp_docs).unwrap().replace("///", "") + "\t */\n";
 377
 378                                 write!(w, "\tpub {}: extern \"C\" fn (", m.sig.ident).unwrap();
 379                                 generated_fields.push((format!("{}", m.sig.ident), None, Some(docs_string)));
 380                                 write_method_params(w, &m.sig, "c_void", types, Some(&meth_gen_types), true, false);
 381                                 writeln!(w, ",").unwrap();
 382                         },
 383                         &syn::TraitItem::Type(_) => {},
 384                         _ => unimplemented!(),
 385                 }
 386         }
 387         // Add functions which may be required for supertrait implementations.
 388         walk_supertraits!(t, Some(&types), (
 389                 ("Clone", _, _) => {
 390                         writeln!(w, "\t/// Called, if set, after this {} has been cloned into a duplicate object.", trait_name).unwrap();
 391                         writeln!(w, "\t/// The new {} is provided, and should be mutated as needed to perform a", trait_name).unwrap();
 392                         writeln!(w, "\t/// deep copy of the object pointed to by this_arg or avoid any double-freeing.").unwrap();
 393                         writeln!(w, "\tpub cloned: Option<extern \"C\" fn (new_{}: &mut {})>,", trait_name, trait_name).unwrap();
 394                         generated_fields.push(("cloned".to_owned(), None, None));
 395                 },
 396                 ("std::cmp::Eq", _, _)|("core::cmp::Eq", _, _) => {
 397                         let eq_docs = "Checks if two objects are equal given this object's this_arg pointer and another object.";
 398                         writeln!(w, "\t/// {}", eq_docs).unwrap();
 399                         writeln!(w, "\tpub eq: extern \"C\" fn (this_arg: *const c_void, other_arg: &{}) -> bool,", trait_name).unwrap();
 400                         generated_fields.push(("eq".to_owned(), None, Some(format!("\t/** {} */\n", eq_docs))));
 401                 },
 402                 ("std::hash::Hash", _, _)|("core::hash::Hash", _, _) => {
 403                         let hash_docs_a = "Calculate a succinct non-cryptographic hash for an object given its this_arg pointer.";
 404                         let hash_docs_b = "This is used, for example, for inclusion of this object in a hash map.";
 405                         writeln!(w, "\t/// {}", hash_docs_a).unwrap();
 406                         writeln!(w, "\t/// {}", hash_docs_b).unwrap();
 407                         writeln!(w, "\tpub hash: extern \"C\" fn (this_arg: *const c_void) -> u64,").unwrap();
 408                         generated_fields.push(("hash".to_owned(), None,
 409                                 Some(format!("\t/**\n\t * {}\n\t * {}\n\t */\n", hash_docs_a, hash_docs_b))));
 410                 },
 411                 ("Send", _, _) => {}, ("Sync", _, _) => {},
 412                 ("std::fmt::Debug", _, _)|("core::fmt::Debug", _, _) => {
 413                         let debug_docs = "Return a human-readable \"debug\" string describing this object";
 414                         writeln!(w, "\t/// {}", debug_docs).unwrap();
 415                         writeln!(w, "\tpub debug_str: extern \"C\" fn (this_arg: *const c_void) -> crate::c_types::Str,").unwrap();
 416                         generated_fields.push(("debug_str".to_owned(), None,
 417                                 Some(format!("\t/**\n\t * {}\n\t */\n", debug_docs))));
 418                 },
 419                 (s, i, _) => {
 420                         // TODO: Both of the below should expose supertrait methods in C++, but doing so is
 421                         // nontrivial.
 422                         generated_fields.push(if types.crate_types.traits.get(s).is_none() {
 423                                 let (docs, name, ret) = convert_trait_impl_field(s);
 424                                 writeln!(w, "\t/// {}", docs).unwrap();
 425                                 writeln!(w, "\tpub {}: extern \"C\" fn (this_arg: *const c_void) -> {},", name, ret).unwrap();
 426                                 (name, None, None) // Assume clonable
 427                         } else {
 428                                 // For in-crate supertraits, just store a C-mapped copy of the supertrait as a member.
 429                                 writeln!(w, "\t/// Implementation of {} for this object.", i).unwrap();
 430                                 let is_clonable = types.is_clonable(s);
 431                                 writeln!(w, "\tpub {}: crate::{},", i, s).unwrap();
 432                                 (format!("{}", i), if !is_clonable {
 433                                         Some(format!("crate::{}_clone_fields", s))
 434                                 } else { None }, None)
 435                         });
 436                 }
 437         ) );
 438         writeln!(w, "\t/// Frees any resources associated with this object given its this_arg pointer.").unwrap();
 439         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();
 440         writeln!(w, "\tpub free: Option<extern \"C\" fn(this_arg: *mut c_void)>,").unwrap();
 441         generated_fields.push(("free".to_owned(), None, None));
 442         writeln!(w, "}}").unwrap();
 443
 444         macro_rules! impl_trait_for_c {
 445                 ($t: expr, $impl_accessor: expr, $type_resolver: expr, $generic_impls: expr) => {
 446                         let mut trait_gen_types = gen_types.push_ctx();
 447                         assert!(trait_gen_types.learn_generics_with_impls(&$t.generics, $generic_impls, $type_resolver));
 448                         for item in $t.items.iter() {
 449                                 match item {
 450                                         syn::TraitItem::Method(m) => {
 451                                                 if let ExportStatus::TestOnly = export_status(&m.attrs) { continue; }
 452                                                 if m.sig.constness.is_some() || m.sig.asyncness.is_some() || m.sig.unsafety.is_some() ||
 453                                                                 m.sig.abi.is_some() || m.sig.variadic.is_some() {
 454                                                         panic!("1");
 455                                                 }
 456                                                 let mut meth_gen_types = trait_gen_types.push_ctx();
 457                                                 assert!(meth_gen_types.learn_generics(&m.sig.generics, $type_resolver));
 458                                                 // Note that we do *not* use the method generics when printing "native"
 459                                                 // rust parts - if the method is generic, we need to print a generic
 460                                                 // method.
 461                                                 write!(w, "\tfn {}", m.sig.ident).unwrap();
 462                                                 $type_resolver.write_rust_generic_param(w, Some(&gen_types), m.sig.generics.params.iter());
 463                                                 write!(w, "(").unwrap();
 464                                                 for inp in m.sig.inputs.iter() {
 465                                                         match inp {
 466                                                                 syn::FnArg::Receiver(recv) => {
 467                                                                         if !recv.attrs.is_empty() || recv.reference.is_none() { panic!("2"); }
 468                                                                         write!(w, "&").unwrap();
 469                                                                         if let Some(lft) = &recv.reference.as_ref().unwrap().1 {
 470                                                                                 write!(w, "'{} ", lft.ident).unwrap();
 471                                                                         }
 472                                                                         if recv.mutability.is_some() {
 473                                                                                 write!(w, "mut self").unwrap();
 474                                                                         } else {
 475                                                                                 write!(w, "self").unwrap();
 476                                                                         }
 477                                                                 },
 478                                                                 syn::FnArg::Typed(arg) => {
 479                                                                         if !arg.attrs.is_empty() { panic!("3"); }
 480                                                                         match &*arg.pat {
 481                                                                                 syn::Pat::Ident(ident) => {
 482                                                                                         if !ident.attrs.is_empty() || ident.by_ref.is_some() ||
 483                                                                                                         ident.mutability.is_some() || ident.subpat.is_some() {
 484                                                                                                 panic!("4");
 485                                                                                         }
 486                                                                                         write!(w, ", mut {}{}: ", if $type_resolver.skip_arg(&*arg.ty, Some(&meth_gen_types)) { "_" } else { "" }, ident.ident).unwrap();
 487                                                                                 }
 488                                                                                 _ => panic!("5"),
 489                                                                         }
 490                                                                         $type_resolver.write_rust_type(w, Some(&gen_types), &*arg.ty, false);
 491                                                                 }
 492                                                         }
 493                                                 }
 494                                                 write!(w, ")").unwrap();
 495                                                 match &m.sig.output {
 496                                                         syn::ReturnType::Type(_, rtype) => {
 497                                                                 write!(w, " -> ").unwrap();
 498                                                                 $type_resolver.write_rust_type(w, Some(&gen_types), &*rtype, false)
 499                                                         },
 500                                                         _ => {},
 501                                                 }
 502                                                 write!(w, " {{\n\t\t").unwrap();
 503                                                 match export_status(&m.attrs) {
 504                                                         ExportStatus::NoExport => {
 505                                                                 panic!("6");
 506                                                         },
 507                                                         _ => {},
 508                                                 }
 509                                                 if let syn::ReturnType::Type(_, rtype) = &m.sig.output {
 510                                                         if let syn::Type::Reference(r) = &**rtype {
 511                                                                 assert_eq!(m.sig.inputs.len(), 1); // Must only take self!
 512                                                                 writeln!(w, "if let Some(f) = self{}.set_{} {{", $impl_accessor, m.sig.ident).unwrap();
 513                                                                 writeln!(w, "\t\t\t(f)(&self{});", $impl_accessor).unwrap();
 514                                                                 write!(w, "\t\t}}\n\t\t").unwrap();
 515                                                                 $type_resolver.write_from_c_conversion_to_ref_prefix(w, &*r.elem, Some(&meth_gen_types));
 516                                                                 write!(w, "self{}.{}", $impl_accessor, m.sig.ident).unwrap();
 517                                                                 $type_resolver.write_from_c_conversion_to_ref_suffix(w, &*r.elem, Some(&meth_gen_types));
 518                                                                 writeln!(w, "\n\t}}").unwrap();
 519                                                                 continue;
 520                                                         }
 521                                                 }
 522                                                 write_method_var_decl_body(w, &m.sig, "\t", $type_resolver, Some(&meth_gen_types), true);
 523                                                 write!(w, "(self{}.{})(", $impl_accessor, m.sig.ident).unwrap();
 524                                                 let mut args = Vec::new();
 525                                                 write_method_call_params(&mut args, &m.sig, "\t", $type_resolver, Some(&meth_gen_types), "", true);
 526                                                 w.write_all(String::from_utf8(args).unwrap().replace("self", &format!("self{}", $impl_accessor)).as_bytes()).unwrap();
 527
 528                                                 writeln!(w, "\n\t}}").unwrap();
 529                                         },
 530                                         &syn::TraitItem::Type(ref t) => {
 531                                                 if t.default.is_some() || t.generics.lt_token.is_some() { panic!("10"); }
 532                                                 let mut bounds_iter = t.bounds.iter();
 533                                                 loop {
 534                                                         match bounds_iter.next().unwrap() {
 535                                                                 syn::TypeParamBound::Trait(tr) => {
 536                                                                         writeln!(w, "\ttype {} = crate::{};", t.ident, $type_resolver.resolve_path(&tr.path, Some(&gen_types))).unwrap();
 537                                                                         for bound in bounds_iter {
 538                                                                                 if let syn::TypeParamBound::Trait(_) = bound { panic!("11"); }
 539                                                                         }
 540                                                                         break;
 541                                                                 },
 542                                                                 syn::TypeParamBound::Lifetime(_) => {},
 543                                                         }
 544                                                 }
 545                                         },
 546                                         _ => panic!("12"),
 547                                 }
 548                         }
 549                 }
 550         }
 551
 552         writeln!(w, "unsafe impl Send for {} {{}}", trait_name).unwrap();
 553         writeln!(w, "unsafe impl Sync for {} {{}}", trait_name).unwrap();
 554
 555         writeln!(w, "#[no_mangle]").unwrap();
 556         writeln!(w, "pub(crate) extern \"C\" fn {}_clone_fields(orig: &{}) -> {} {{", trait_name, trait_name, trait_name).unwrap();
 557         writeln!(w, "\t{} {{", trait_name).unwrap();
 558         writeln!(w, "\t\tthis_arg: orig.this_arg,").unwrap();
 559         for (field, clone_fn, _) in generated_fields.iter() {
 560                 if let Some(f) = clone_fn {
 561                         // If the field isn't clonable, blindly assume its a trait and hope for the best.
 562                         writeln!(w, "\t\t{}: {}(&orig.{}),", field, f, field).unwrap();
 563                 } else {
 564                         writeln!(w, "\t\t{}: Clone::clone(&orig.{}),", field, field).unwrap();
 565                 }
 566         }
 567         writeln!(w, "\t}}\n}}").unwrap();
 568
 569         // Implement supertraits for the C-mapped struct.
 570         walk_supertraits!(t, Some(&types), (
 571                 ("std::cmp::Eq", _, _)|("core::cmp::Eq", _, _) => {
 572                         writeln!(w, "impl core::cmp::Eq for {} {{}}", trait_name).unwrap();
 573                         writeln!(w, "impl core::cmp::PartialEq for {} {{", trait_name).unwrap();
 574                         writeln!(w, "\tfn eq(&self, o: &Self) -> bool {{ (self.eq)(self.this_arg, o) }}\n}}").unwrap();
 575                 },
 576                 ("std::hash::Hash", _, _)|("core::hash::Hash", _, _) => {
 577                         writeln!(w, "impl core::hash::Hash for {} {{", trait_name).unwrap();
 578                         writeln!(w, "\tfn hash<H: core::hash::Hasher>(&self, hasher: &mut H) {{ hasher.write_u64((self.hash)(self.this_arg)) }}\n}}").unwrap();
 579                 },
 580                 ("Send", _, _) => {}, ("Sync", _, _) => {},
 581                 ("Clone", _, _) => {
 582                         writeln!(w, "#[no_mangle]").unwrap();
 583                         writeln!(w, "/// Creates a copy of a {}", trait_name).unwrap();
 584                         writeln!(w, "pub extern \"C\" fn {}_clone(orig: &{}) -> {} {{", trait_name, trait_name, trait_name).unwrap();
 585                         writeln!(w, "\tlet mut res = {}_clone_fields(orig);", trait_name).unwrap();
 586                         writeln!(w, "\tif let Some(f) = orig.cloned {{ (f)(&mut res) }};").unwrap();
 587                         writeln!(w, "\tres\n}}").unwrap();
 588                         writeln!(w, "impl Clone for {} {{", trait_name).unwrap();
 589                         writeln!(w, "\tfn clone(&self) -> Self {{").unwrap();
 590                         writeln!(w, "\t\t{}_clone(self)", trait_name).unwrap();
 591                         writeln!(w, "\t}}\n}}").unwrap();
 592                 },
 593                 ("std::fmt::Debug", _, _)|("core::fmt::Debug", _, _) => {
 594                         writeln!(w, "impl core::fmt::Debug for {} {{", trait_name).unwrap();
 595                         writeln!(w, "\tfn fmt(&self, f: &mut core::fmt::Formatter) -> Result<(), core::fmt::Error> {{").unwrap();
 596                         writeln!(w, "\t\tf.write_str((self.debug_str)(self.this_arg).into_str())").unwrap();
 597                         writeln!(w, "\t}}").unwrap();
 598                         writeln!(w, "}}").unwrap();
 599                 },
 600                 (s, i, generic_args) => {
 601                         if let Some(supertrait) = types.crate_types.traits.get(s) {
 602                                 let resolver = get_module_type_resolver!(s, types.crate_libs, types.crate_types);
 603
 604                                 // Blindly assume that the same imports where `supertrait` is defined are also
 605                                 // imported here. This will almost certainly break at some point, but it should be
 606                                 // a compilation failure when it does so.
 607                                 write!(w, "impl").unwrap();
 608                                 maybe_write_lifetime_generics(w, &supertrait.generics, types);
 609                                 write!(w, " {}", s).unwrap();
 610                                 maybe_write_generics(w, &supertrait.generics, generic_args, types, false);
 611                                 writeln!(w, " for {} {{", trait_name).unwrap();
 612
 613                                 impl_trait_for_c!(supertrait, format!(".{}", i), &resolver, generic_args);
 614                                 writeln!(w, "}}").unwrap();
 615                         } else {
 616                                 do_write_impl_trait(w, s, i, &trait_name);
 617                         }
 618                 }
 619         ) );
 620
 621         // Finally, implement the original Rust trait for the newly created mapped trait.
 622         writeln!(w, "\nuse {}::{} as rust{};", types.module_path, t.ident, trait_name).unwrap();
 623         if implementable {
 624                 write!(w, "impl").unwrap();
 625                 maybe_write_lifetime_generics(w, &t.generics, types);
 626                 write!(w, " rust{}", t.ident).unwrap();
 627                 maybe_write_generics(w, &t.generics, &syn::PathArguments::None, types, false);
 628                 writeln!(w, " for {} {{", trait_name).unwrap();
 629                 impl_trait_for_c!(t, "", types, &syn::PathArguments::None);
 630                 writeln!(w, "}}\n").unwrap();
 631                 writeln!(w, "// We're essentially a pointer already, or at least a set of pointers, so allow us to be used").unwrap();
 632                 writeln!(w, "// directly as a Deref trait in higher-level structs:").unwrap();
 633                 writeln!(w, "impl core::ops::Deref for {} {{\n\ttype Target = Self;", trait_name).unwrap();
 634                 writeln!(w, "\tfn deref(&self) -> &Self {{\n\t\tself\n\t}}\n}}").unwrap();
 635         }
 636
 637         writeln!(w, "/// Calls the free function if one is set").unwrap();
 638         writeln!(w, "#[no_mangle]\npub extern \"C\" fn {}_free(this_ptr: {}) {{ }}", trait_name, trait_name).unwrap();
 639         writeln!(w, "impl Drop for {} {{", trait_name).unwrap();
 640         writeln!(w, "\tfn drop(&mut self) {{").unwrap();
 641         writeln!(w, "\t\tif let Some(f) = self.free {{").unwrap();
 642         writeln!(w, "\t\t\tf(self.this_arg);").unwrap();
 643         writeln!(w, "\t\t}}\n\t}}\n}}").unwrap();
 644
 645         write_cpp_wrapper(cpp_headers, &trait_name, true, Some(generated_fields.drain(..)
 646                 .filter_map(|(name, _, docs)| if let Some(docs) = docs { Some((name, docs)) } else { None }).collect()));
 647 }
 648
 649 /// Write out a simple "opaque" type (eg structs) which contain a pointer to the native Rust type
 650 /// and a flag to indicate whether Drop'ing the mapped struct drops the underlying Rust type.
 651 ///
 652 /// Also writes out a _free function and a C++ wrapper which handles calling _free.
 653 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) {
 654         // If we directly read the original type by its original name, cbindgen hits
 655         // https://github.com/eqrion/cbindgen/issues/286 Thus, instead, we import it as a temporary
 656         // name and then reference it by that name, which works around the issue.
 657         write!(w, "\nuse {}::{} as native{}Import;\npub(crate) type native{} = native{}Import", types.module_path, ident, ident, ident, ident).unwrap();
 658         maybe_write_generics(w, &generics, &syn::PathArguments::None, &types, true);
 659         writeln!(w, ";\n").unwrap();
 660         writeln!(extra_headers, "struct native{}Opaque;\ntypedef struct native{}Opaque LDKnative{};", ident, ident, ident).unwrap();
 661         writeln_docs(w, &attrs, "");
 662         writeln!(w, "#[must_use]\n#[repr(C)]\npub struct {} {{", struct_name).unwrap();
 663         writeln!(w, "\t/// A pointer to the opaque Rust object.\n").unwrap();
 664         writeln!(w, "\t/// Nearly everywhere, inner must be non-null, however in places where").unwrap();
 665         writeln!(w, "\t/// the Rust equivalent takes an Option, it may be set to null to indicate None.").unwrap();
 666         writeln!(w, "\tpub inner: *mut native{},", ident).unwrap();
 667         writeln!(w, "\t/// Indicates that this is the only struct which contains the same pointer.\n").unwrap();
 668         writeln!(w, "\t/// Rust functions which take ownership of an object provided via an argument require").unwrap();
 669         writeln!(w, "\t/// this to be true and invalidate the object pointed to by inner.").unwrap();
 670         writeln!(w, "\tpub is_owned: bool,").unwrap();
 671         writeln!(w, "}}\n").unwrap();
 672         writeln!(w, "impl Drop for {} {{\n\tfn drop(&mut self) {{", struct_name).unwrap();
 673         writeln!(w, "\t\tif self.is_owned && !<*mut native{}>::is_null(self.inner) {{", ident).unwrap();
 674         writeln!(w, "\t\t\tlet _ = unsafe {{ Box::from_raw(ObjOps::untweak_ptr(self.inner)) }};\n\t\t}}\n\t}}\n}}").unwrap();
 675         writeln!(w, "/// Frees any resources used by the {}, if is_owned is set and inner is non-NULL.", struct_name).unwrap();
 676         writeln!(w, "#[no_mangle]\npub extern \"C\" fn {}_free(this_obj: {}) {{ }}", struct_name, struct_name).unwrap();
 677         writeln!(w, "#[allow(unused)]").unwrap();
 678         writeln!(w, "/// Used only if an object of this type is returned as a trait impl by a method").unwrap();
 679         writeln!(w, "pub(crate) extern \"C\" fn {}_free_void(this_ptr: *mut c_void) {{", struct_name).unwrap();
 680         writeln!(w, "\tlet _ = unsafe {{ Box::from_raw(this_ptr as *mut native{}) }};\n}}", struct_name).unwrap();
 681         writeln!(w, "#[allow(unused)]").unwrap();
 682         writeln!(w, "impl {} {{", struct_name).unwrap();
 683         writeln!(w, "\tpub(crate) fn get_native_ref(&self) -> &'static native{} {{", struct_name).unwrap();
 684         writeln!(w, "\t\tunsafe {{ &*ObjOps::untweak_ptr(self.inner) }}").unwrap();
 685         writeln!(w, "\t}}").unwrap();
 686         writeln!(w, "\tpub(crate) fn get_native_mut_ref(&self) -> &'static mut native{} {{", struct_name).unwrap();
 687         writeln!(w, "\t\tunsafe {{ &mut *ObjOps::untweak_ptr(self.inner) }}").unwrap();
 688         writeln!(w, "\t}}").unwrap();
 689         writeln!(w, "\t/// When moving out of the pointer, we have to ensure we aren't a reference, this makes that easy").unwrap();
 690         writeln!(w, "\tpub(crate) fn take_inner(mut self) -> *mut native{} {{", struct_name).unwrap();
 691         writeln!(w, "\t\tassert!(self.is_owned);").unwrap();
 692         writeln!(w, "\t\tlet ret = ObjOps::untweak_ptr(self.inner);").unwrap();
 693         writeln!(w, "\t\tself.inner = core::ptr::null_mut();").unwrap();
 694         writeln!(w, "\t\tret").unwrap();
 695         writeln!(w, "\t}}\n}}").unwrap();
 696
 697         write_cpp_wrapper(cpp_headers, &format!("{}", ident), true, None);
 698 }
 699
 700 /// Writes out all the relevant mappings for a Rust struct, deferring to writeln_opaque to generate
 701 /// the struct itself, and then writing getters and setters for public, understood-type fields and
 702 /// a constructor if every field is public.
 703 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) {
 704         if export_status(&s.attrs) != ExportStatus::Export { return; }
 705
 706         let struct_name = &format!("{}", s.ident);
 707         writeln_opaque(w, &s.ident, struct_name, &s.generics, &s.attrs, types, extra_headers, cpp_headers);
 708
 709         let mut self_path_segs = syn::punctuated::Punctuated::new();
 710         self_path_segs.push(s.ident.clone().into());
 711         let self_path = syn::Path { leading_colon: None, segments: self_path_segs};
 712         let mut gen_types = GenericTypes::new(Some(types.resolve_path(&self_path, None)));
 713         assert!(gen_types.learn_generics(&s.generics, types));
 714
 715         let mut all_fields_settable = true;
 716         macro_rules! define_field {
 717                 ($new_name: expr, $real_name: expr, $field: expr) => {
 718                         if let syn::Visibility::Public(_) = $field.vis {
 719                                 let export = export_status(&$field.attrs);
 720                                 match export {
 721                                         ExportStatus::Export => {},
 722                                         ExportStatus::NoExport|ExportStatus::TestOnly => {
 723                                                 all_fields_settable = false;
 724                                                 continue
 725                                         },
 726                                         ExportStatus::NotImplementable => panic!("(C-not implementable) must only appear on traits"),
 727                                 }
 728
 729                                 if let Some(ref_type) = types.create_ownable_reference(&$field.ty, Some(&gen_types)) {
 730                                         if types.understood_c_type(&ref_type, Some(&gen_types)) {
 731                                                 writeln_arg_docs(w, &$field.attrs, "", types, Some(&gen_types), vec![].drain(..), Some(&ref_type));
 732                                                 write!(w, "#[no_mangle]\npub extern \"C\" fn {}_get_{}(this_ptr: &{}) -> ", struct_name, $new_name, struct_name).unwrap();
 733                                                 types.write_c_type(w, &ref_type, Some(&gen_types), true);
 734                                                 write!(w, " {{\n\tlet mut inner_val = &mut this_ptr.get_native_mut_ref().{};\n\t", $real_name).unwrap();
 735                                                 let local_var = types.write_to_c_conversion_from_ownable_ref_new_var(w, &format_ident!("inner_val"), &ref_type, Some(&gen_types));
 736                                                 if local_var { write!(w, "\n\t").unwrap(); }
 737                                                 types.write_to_c_conversion_inline_prefix(w, &ref_type, Some(&gen_types), true);
 738                                                 write!(w, "inner_val").unwrap();
 739                                                 types.write_to_c_conversion_inline_suffix(w, &ref_type, Some(&gen_types), true);
 740                                                 writeln!(w, "\n}}").unwrap();
 741                                         } else {
 742                                                 // If the type isn't reference-able, but is clonable, export a getter that just clones
 743                                                 if types.understood_c_type(&$field.ty, Some(&gen_types)) {
 744                                                         let mut v = Vec::new();
 745                                                         types.write_c_type(&mut v, &$field.ty, Some(&gen_types), true);
 746                                                         let s = String::from_utf8(v).unwrap();
 747                                                         if types.is_clonable(&s) {
 748                                                                 writeln_arg_docs(w, &$field.attrs, "", types, Some(&gen_types), vec![].drain(..), Some(&$field.ty));
 749                                                                 writeln!(w, "///\n/// Returns a copy of the field.").unwrap();
 750                                                                 write!(w, "#[no_mangle]\npub extern \"C\" fn {}_get_{}(this_ptr: &{}) -> {}", struct_name, $new_name, struct_name, s).unwrap();
 751                                                                 write!(w, " {{\n\tlet mut inner_val = this_ptr.get_native_mut_ref().{}.clone();\n\t", $real_name).unwrap();
 752                                                                 let local_var = types.write_to_c_conversion_new_var(w, &format_ident!("inner_val"), &$field.ty, Some(&gen_types), true);
 753                                                                 if local_var { write!(w, "\n\t").unwrap(); }
 754                                                                 types.write_to_c_conversion_inline_prefix(w, &$field.ty, Some(&gen_types), true);
 755                                                                 write!(w, "inner_val").unwrap();
 756                                                                 types.write_to_c_conversion_inline_suffix(w, &$field.ty, Some(&gen_types), true);
 757                                                                 writeln!(w, "\n}}").unwrap();
 758                                                         }
 759                                                 }
 760                                         }
 761                                 }
 762
 763                                 if types.understood_c_type(&$field.ty, Some(&gen_types)) {
 764                                         writeln_arg_docs(w, &$field.attrs, "", types, Some(&gen_types), vec![("val".to_owned(), &$field.ty)].drain(..), None);
 765                                         write!(w, "#[no_mangle]\npub extern \"C\" fn {}_set_{}(this_ptr: &mut {}, mut val: ", struct_name, $new_name, struct_name).unwrap();
 766                                         types.write_c_type(w, &$field.ty, Some(&gen_types), false);
 767                                         write!(w, ") {{\n\t").unwrap();
 768                                         let local_var = types.write_from_c_conversion_new_var(w, &format_ident!("val"), &$field.ty, Some(&gen_types));
 769                                         if local_var { write!(w, "\n\t").unwrap(); }
 770                                         write!(w, "unsafe {{ &mut *ObjOps::untweak_ptr(this_ptr.inner) }}.{} = ", $real_name).unwrap();
 771                                         types.write_from_c_conversion_prefix(w, &$field.ty, Some(&gen_types));
 772                                         write!(w, "val").unwrap();
 773                                         types.write_from_c_conversion_suffix(w, &$field.ty, Some(&gen_types));
 774                                         writeln!(w, ";\n}}").unwrap();
 775                                 } else { all_fields_settable = false; }
 776                         } else { all_fields_settable = false; }
 777                 }
 778         }
 779
 780         match &s.fields {
 781                 syn::Fields::Named(fields) => {
 782                         for field in fields.named.iter() {
 783                                 if let Some(ident) = &field.ident {
 784                                         define_field!(ident, ident, field);
 785                                 } else { all_fields_settable = false; }
 786                         }
 787                 }
 788                 syn::Fields::Unnamed(fields) => {
 789                         for (idx, field) in fields.unnamed.iter().enumerate() {
 790                                 define_field!(('a' as u8 + idx as u8) as char, ('0' as u8 + idx as u8) as char, field);
 791                         }
 792                 }
 793                 _ => unimplemented!()
 794         }
 795
 796         if all_fields_settable {
 797                 // Build a constructor!
 798                 writeln!(w, "/// Constructs a new {} given each field", struct_name).unwrap();
 799                 write!(w, "#[must_use]\n#[no_mangle]\npub extern \"C\" fn {}_new(", struct_name).unwrap();
 800
 801                 match &s.fields {
 802                         syn::Fields::Named(fields) => {
 803                                 for (idx, field) in fields.named.iter().enumerate() {
 804                                         if idx != 0 { write!(w, ", ").unwrap(); }
 805                                         write!(w, "mut {}_arg: ", field.ident.as_ref().unwrap()).unwrap();
 806                                         types.write_c_type(w, &field.ty, Some(&gen_types), false);
 807                                 }
 808                         }
 809                         syn::Fields::Unnamed(fields) => {
 810                                 for (idx, field) in fields.unnamed.iter().enumerate() {
 811                                         if idx != 0 { write!(w, ", ").unwrap(); }
 812                                         write!(w, "mut {}_arg: ", ('a' as u8 + idx as u8) as char).unwrap();
 813                                         types.write_c_type(w, &field.ty, Some(&gen_types), false);
 814                                 }
 815                         }
 816                         _ => unreachable!()
 817                 }
 818                 write!(w, ") -> {} {{\n\t", struct_name).unwrap();
 819                 match &s.fields {
 820                         syn::Fields::Named(fields) => {
 821                                 for field in fields.named.iter() {
 822                                         let field_ident = format_ident!("{}_arg", field.ident.as_ref().unwrap());
 823                                         if types.write_from_c_conversion_new_var(w, &field_ident, &field.ty, Some(&gen_types)) {
 824                                                 write!(w, "\n\t").unwrap();
 825                                         }
 826                                 }
 827                         },
 828                         syn::Fields::Unnamed(fields) => {
 829                                 for (idx, field) in fields.unnamed.iter().enumerate() {
 830                                         let field_ident = format_ident!("{}_arg", ('a' as u8 + idx as u8) as char);
 831                                         if types.write_from_c_conversion_new_var(w, &field_ident, &field.ty, Some(&gen_types)) {
 832                                                 write!(w, "\n\t").unwrap();
 833                                         }
 834                                 }
 835                         },
 836                         _ => unreachable!()
 837                 }
 838                 write!(w, "{} {{ inner: ObjOps::heap_alloc(", struct_name).unwrap();
 839                 match &s.fields {
 840                         syn::Fields::Named(fields) => {
 841                                 writeln!(w, "native{} {{", s.ident).unwrap();
 842                                 for field in fields.named.iter() {
 843                                         write!(w, "\t\t{}: ", field.ident.as_ref().unwrap()).unwrap();
 844                                         types.write_from_c_conversion_prefix(w, &field.ty, Some(&gen_types));
 845                                         write!(w, "{}_arg", field.ident.as_ref().unwrap()).unwrap();
 846                                         types.write_from_c_conversion_suffix(w, &field.ty, Some(&gen_types));
 847                                         writeln!(w, ",").unwrap();
 848                                 }
 849                                 write!(w, "\t}}").unwrap();
 850                         },
 851                         syn::Fields::Unnamed(fields) => {
 852                                 assert!(!s.generics.params.iter()
 853                                         .any(|gen| if let syn::GenericParam::Lifetime(_) = gen { false } else { true }));
 854                                 writeln!(w, "{} (", types.maybe_resolve_ident(&s.ident).unwrap()).unwrap();
 855                                 for (idx, field) in fields.unnamed.iter().enumerate() {
 856                                         write!(w, "\t\t").unwrap();
 857                                         types.write_from_c_conversion_prefix(w, &field.ty, Some(&gen_types));
 858                                         write!(w, "{}_arg", ('a' as u8 + idx as u8) as char).unwrap();
 859                                         types.write_from_c_conversion_suffix(w, &field.ty, Some(&gen_types));
 860                                         writeln!(w, ",").unwrap();
 861                                 }
 862                                 write!(w, "\t)").unwrap();
 863                         },
 864                         _ => unreachable!()
 865                 }
 866                 writeln!(w, "), is_owned: true }}\n}}").unwrap();
 867         }
 868 }
 869
 870 /// Prints a relevant conversion for impl *
 871 ///
 872 /// For simple impl Struct {}s, this just outputs the wrapper functions as Struct_fn_name() { .. }.
 873 ///
 874 /// For impl Trait for Struct{}s, this non-exported generates wrapper functions as
 875 /// Trait_Struct_fn_name and a Struct_as_Trait(&struct) -> Trait function which returns a populated
 876 /// Trait struct containing a pointer to the passed struct's inner field and the wrapper functions.
 877 ///
 878 /// A few non-crate Traits are hard-coded including Default.
 879 fn writeln_impl<W: std::io::Write>(w: &mut W, w_uses: &mut HashSet<String, NonRandomHash>, i: &syn::ItemImpl, types: &mut TypeResolver) {
 880         match export_status(&i.attrs) {
 881                 ExportStatus::Export => {},
 882                 ExportStatus::NoExport|ExportStatus::TestOnly => return,
 883                 ExportStatus::NotImplementable => panic!("(C-not implementable) must only appear on traits"),
 884         }
 885
 886         if let syn::Type::Tuple(_) = &*i.self_ty {
 887                 if types.understood_c_type(&*i.self_ty, None) {
 888                         let mut gen_types = GenericTypes::new(None);
 889                         if !gen_types.learn_generics(&i.generics, types) {
 890                                 eprintln!("Not implementing anything for `impl (..)` due to not understood generics");
 891                                 return;
 892                         }
 893
 894                         if i.defaultness.is_some() || i.unsafety.is_some() { unimplemented!(); }
 895                         if let Some(trait_path) = i.trait_.as_ref() {
 896                                 if trait_path.0.is_some() { unimplemented!(); }
 897                                 if types.understood_c_path(&trait_path.1) {
 898                                         eprintln!("Not implementing anything for `impl Trait for (..)` - we only support manual defines");
 899                                         return;
 900                                 } else {
 901                                         // Just do a manual implementation:
 902                                         maybe_convert_trait_impl(w, &trait_path.1, &*i.self_ty, types, &gen_types);
 903                                 }
 904                         } else {
 905                                 eprintln!("Not implementing anything for plain `impl (..)` block - we only support `impl Trait for (..)` blocks");
 906                                 return;
 907                         }
 908                 }
 909                 return;
 910         }
 911         if let &syn::Type::Path(ref p) = &*i.self_ty {
 912                 if p.qself.is_some() { unimplemented!(); }
 913                 let ident = &p.path.segments.last().unwrap().ident;
 914                 if let Some(resolved_path) = types.maybe_resolve_path(&p.path, None) {
 915                         if types.crate_types.opaques.contains_key(&resolved_path) || types.crate_types.mirrored_enums.contains_key(&resolved_path) ||
 916                                 // At least for core::infallible::Infallible we need to support mapping an
 917                                 // out-of-crate trait implementation.
 918                                 (types.understood_c_path(&p.path) && first_seg_is_stdlib(resolved_path.split("::").next().unwrap())) {
 919                                 if !types.understood_c_path(&p.path) {
 920                                         eprintln!("Not implementing anything for impl {} as the type is not understood (probably C-not exported)", ident);
 921                                         return;
 922                                 }
 923
 924                                 let mut gen_types = GenericTypes::new(Some(resolved_path.clone()));
 925                                 if !gen_types.learn_generics(&i.generics, types) {
 926                                         eprintln!("Not implementing anything for impl {} due to not understood generics", ident);
 927                                         return;
 928                                 }
 929
 930                                 if i.defaultness.is_some() || i.unsafety.is_some() { unimplemented!(); }
 931                                 if let Some(trait_path) = i.trait_.as_ref() {
 932                                         if trait_path.0.is_some() { unimplemented!(); }
 933                                         if types.understood_c_path(&trait_path.1) {
 934                                                 let full_trait_path = types.resolve_path(&trait_path.1, None);
 935                                                 let trait_obj = *types.crate_types.traits.get(&full_trait_path).unwrap();
 936
 937                                                 let supertrait_name;
 938                                                 let supertrait_resolver;
 939                                                 walk_supertraits!(trait_obj, Some(&types), (
 940                                                         (s, _i, _) => {
 941                                                                 if let Some(supertrait) = types.crate_types.traits.get(s) {
 942                                                                         supertrait_name = s.to_string();
 943                                                                         supertrait_resolver = get_module_type_resolver!(supertrait_name, types.crate_libs, types.crate_types);
 944                                                                         gen_types.learn_associated_types(&supertrait, &supertrait_resolver);
 945                                                                         break;
 946                                                                 }
 947                                                         }
 948                                                 ) );
 949                                                 // We learn the associated types maping from the original trait object.
 950                                                 // That's great, except that they are unresolved idents, so if we learn
 951                                                 // mappings from a trai defined in a different file, we may mis-resolve or
 952                                                 // fail to resolve the mapped types. Thus, we have to construct a new
 953                                                 // resolver for the module that the trait was defined in here first.
 954                                                 let mut trait_resolver = get_module_type_resolver!(full_trait_path, types.crate_libs, types.crate_types);
 955                                                 gen_types.learn_associated_types(trait_obj, &trait_resolver);
 956                                                 let mut impl_associated_types = HashMap::new();
 957                                                 for item in i.items.iter() {
 958                                                         match item {
 959                                                                 syn::ImplItem::Type(t) => {
 960                                                                         if let syn::Type::Path(p) = &t.ty {
 961                                                                                 if let Some(id) = single_ident_generic_path_to_ident(&p.path) {
 962                                                                                         impl_associated_types.insert(&t.ident, id);
 963                                                                                 }
 964                                                                         }
 965                                                                 },
 966                                                                 _ => {},
 967                                                         }
 968                                                 }
 969
 970                                                 let export = export_status(&trait_obj.attrs);
 971                                                 match export {
 972                                                         ExportStatus::Export|ExportStatus::NotImplementable => {},
 973                                                         ExportStatus::NoExport|ExportStatus::TestOnly => return,
 974                                                 }
 975
 976                                                 // For cases where we have a concrete native object which implements a
 977                                                 // trait and need to return the C-mapped version of the trait, provide a
 978                                                 // From<> implementation which does all the work to ensure free is handled
 979                                                 // properly. This way we can call this method from deep in the
 980                                                 // type-conversion logic without actually knowing the concrete native type.
 981                                                 if !resolved_path.starts_with(types.module_path) {
 982                                                         if !first_seg_is_stdlib(resolved_path.split("::").next().unwrap()) {
 983                                                                 w_uses.insert(format!("use crate::{}::native{} as native{};", resolved_path.rsplitn(2, "::").skip(1).next().unwrap(), ident, ident));
 984                                                                 w_uses.insert(format!("use crate::{};", resolved_path));
 985                                                                 w_uses.insert(format!("use crate::{}_free_void;", resolved_path));
 986                                                         } else {
 987                                                                 w_uses.insert(format!("use {} as native{};", resolved_path, ident));
 988                                                         }
 989                                                 }
 990                                                 writeln!(w, "impl From<native{}> for crate::{} {{", ident, full_trait_path).unwrap();
 991                                                 writeln!(w, "\tfn from(obj: native{}) -> Self {{", ident).unwrap();
 992                                                 if is_type_unconstructable(&resolved_path) {
 993                                                         writeln!(w, "\t\tunreachable!();").unwrap();
 994                                                 } else {
 995                                                         writeln!(w, "\t\tlet mut rust_obj = {} {{ inner: ObjOps::heap_alloc(obj), is_owned: true }};", ident).unwrap();
 996                                                         writeln!(w, "\t\tlet mut ret = {}_as_{}(&rust_obj);", ident, trait_obj.ident).unwrap();
 997                                                         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();
 998                                                         writeln!(w, "\t\trust_obj.inner = core::ptr::null_mut();").unwrap();
 999                                                         writeln!(w, "\t\tret.free = Some({}_free_void);", ident).unwrap();
1000                                                         writeln!(w, "\t\tret").unwrap();
1001                                                 }
1002                                                 writeln!(w, "\t}}\n}}").unwrap();
1003                                                 if is_type_unconstructable(&resolved_path) {
1004                                                         // We don't bother with Struct_as_Trait conversion for types which must
1005                                                         // never be instantiated, so just return early.
1006                                                         return;
1007                                                 }
1008
1009                                                 writeln!(w, "/// Constructs a new {} which calls the relevant methods on this_arg.", trait_obj.ident).unwrap();
1010                                                 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();
1011                                                 write!(w, "#[no_mangle]\npub extern \"C\" fn {}_as_{}(this_arg: &{}) -> crate::{} {{\n", ident, trait_obj.ident, ident, full_trait_path).unwrap();
1012                                                 writeln!(w, "\tcrate::{} {{", full_trait_path).unwrap();
1013                                                 writeln!(w, "\t\tthis_arg: unsafe {{ ObjOps::untweak_ptr((*this_arg).inner) as *mut c_void }},").unwrap();
1014                                                 writeln!(w, "\t\tfree: None,").unwrap();
1015
1016                                                 macro_rules! write_meth {
1017                                                         ($m: expr, $trait: expr, $indent: expr) => {
1018                                                                 let trait_method = $trait.items.iter().filter_map(|item| {
1019                                                                         if let syn::TraitItem::Method(t_m) = item { Some(t_m) } else { None }
1020                                                                 }).find(|trait_meth| trait_meth.sig.ident == $m.sig.ident).unwrap();
1021                                                                 match export_status(&trait_method.attrs) {
1022                                                                         ExportStatus::Export => {},
1023                                                                         ExportStatus::NoExport => {
1024                                                                                 write!(w, "{}\t\t//XXX: Need to export {}\n", $indent, $m.sig.ident).unwrap();
1025                                                                                 continue;
1026                                                                         },
1027                                                                         ExportStatus::TestOnly => continue,
1028                                                                         ExportStatus::NotImplementable => panic!("(C-not implementable) must only appear on traits"),
1029                                                                 }
1030
1031                                                                 let mut printed = false;
1032                                                                 if let syn::ReturnType::Type(_, rtype) = &$m.sig.output {
1033                                                                         if let syn::Type::Reference(r) = &**rtype {
1034                                                                                 write!(w, "\n\t\t{}{}: ", $indent, $m.sig.ident).unwrap();
1035                                                                                 types.write_empty_rust_val(Some(&gen_types), w, &*r.elem);
1036                                                                                 writeln!(w, ",\n{}\t\tset_{}: Some({}_{}_set_{}),", $indent, $m.sig.ident, ident, $trait.ident, $m.sig.ident).unwrap();
1037                                                                                 printed = true;
1038                                                                         }
1039                                                                 }
1040                                                                 if !printed {
1041                                                                         write!(w, "{}\t\t{}: {}_{}_{},\n", $indent, $m.sig.ident, ident, $trait.ident, $m.sig.ident).unwrap();
1042                                                                 }
1043                                                         }
1044                                                 }
1045                                                 for item in trait_obj.items.iter() {
1046                                                         match item {
1047                                                                 syn::TraitItem::Method(m) => {
1048                                                                         write_meth!(m, trait_obj, "");
1049                                                                 },
1050                                                                 _ => {},
1051                                                         }
1052                                                 }
1053                                                 let mut requires_clone = false;
1054                                                 walk_supertraits!(trait_obj, Some(&types), (
1055                                                         ("Clone", _, _) => {
1056                                                                 requires_clone = true;
1057                                                                 writeln!(w, "\t\tcloned: Some({}_{}_cloned),", trait_obj.ident, ident).unwrap();
1058                                                         },
1059                                                         ("Sync", _, _) => {}, ("Send", _, _) => {},
1060                                                         ("std::marker::Sync", _, _) => {}, ("std::marker::Send", _, _) => {},
1061                                                         ("core::fmt::Debug", _, _) => {},
1062                                                         (s, t, _) => {
1063                                                                 if let Some(supertrait_obj) = types.crate_types.traits.get(s) {
1064                                                                         writeln!(w, "\t\t{}: crate::{} {{", t, s).unwrap();
1065                                                                         writeln!(w, "\t\t\tthis_arg: unsafe {{ ObjOps::untweak_ptr((*this_arg).inner) as *mut c_void }},").unwrap();
1066                                                                         writeln!(w, "\t\t\tfree: None,").unwrap();
1067                                                                         for item in supertrait_obj.items.iter() {
1068                                                                                 match item {
1069                                                                                         syn::TraitItem::Method(m) => {
1070                                                                                                 write_meth!(m, supertrait_obj, "\t");
1071                                                                                         },
1072                                                                                         _ => {},
1073                                                                                 }
1074                                                                         }
1075                                                                         write!(w, "\t\t}},\n").unwrap();
1076                                                                 } else {
1077                                                                         write_trait_impl_field_assign(w, s, ident);
1078                                                                 }
1079                                                         }
1080                                                 ) );
1081                                                 writeln!(w, "\t}}\n}}\n").unwrap();
1082
1083                                                 macro_rules! impl_meth {
1084                                                         ($m: expr, $trait_meth: expr, $trait_path: expr, $trait: expr, $indent: expr, $types: expr) => {
1085                                                                 let trait_method = $trait.items.iter().filter_map(|item| {
1086                                                                         if let syn::TraitItem::Method(t_m) = item { Some(t_m) } else { None }
1087                                                                 }).find(|trait_meth| trait_meth.sig.ident == $m.sig.ident).unwrap();
1088                                                                 match export_status(&trait_method.attrs) {
1089                                                                         ExportStatus::Export => {},
1090                                                                         ExportStatus::NoExport|ExportStatus::TestOnly => continue,
1091                                                                         ExportStatus::NotImplementable => panic!("(C-not implementable) must only appear on traits"),
1092                                                                 }
1093
1094                                                                 if let syn::ReturnType::Type(_, _) = &$m.sig.output {
1095                                                                         writeln!(w, "#[must_use]").unwrap();
1096                                                                 }
1097                                                                 write!(w, "extern \"C\" fn {}_{}_{}(", ident, $trait.ident, $m.sig.ident).unwrap();
1098                                                                 let mut meth_gen_types = gen_types.push_ctx();
1099                                                                 assert!(meth_gen_types.learn_generics(&$m.sig.generics, $types));
1100                                                                 let mut uncallable_function = false;
1101                                                                 for inp in $m.sig.inputs.iter() {
1102                                                                         match inp {
1103                                                                                 syn::FnArg::Typed(arg) => {
1104                                                                                         if $types.skip_arg(&*arg.ty, Some(&meth_gen_types)) { continue; }
1105                                                                                         let mut c_type = Vec::new();
1106                                                                                         $types.write_c_type(&mut c_type, &*arg.ty, Some(&meth_gen_types), false);
1107                                                                                         if is_type_unconstructable(&String::from_utf8(c_type).unwrap()) {
1108                                                                                                 uncallable_function = true;
1109                                                                                         }
1110                                                                                 }
1111                                                                                 _ => {}
1112                                                                         }
1113                                                                 }
1114                                                                 write_method_params(w, &$trait_meth.sig, "c_void", &mut trait_resolver, Some(&meth_gen_types), true, true);
1115                                                                 write!(w, " {{\n\t").unwrap();
1116                                                                 if uncallable_function {
1117                                                                         write!(w, "unreachable!();").unwrap();
1118                                                                 } else {
1119                                                                         write_method_var_decl_body(w, &$trait_meth.sig, "", &mut trait_resolver, Some(&meth_gen_types), false);
1120                                                                         let mut takes_self = false;
1121                                                                         for inp in $m.sig.inputs.iter() {
1122                                                                                 if let syn::FnArg::Receiver(_) = inp {
1123                                                                                         takes_self = true;
1124                                                                                 }
1125                                                                         }
1126
1127                                                                         let mut t_gen_args = String::new();
1128                                                                         for (idx, _) in $trait.generics.params.iter().enumerate() {
1129                                                                                 if idx != 0 { t_gen_args += ", " };
1130                                                                                 t_gen_args += "_"
1131                                                                         }
1132                                                                         // rustc doesn't like <_> if the _ is actually a lifetime, so
1133                                                                         // if all the parameters are lifetimes just skip it.
1134                                                                         let mut nonlifetime_param = false;
1135                                                                         for param in $trait.generics.params.iter() {
1136                                                                                 if let syn::GenericParam::Lifetime(_) = param {}
1137                                                                                 else { nonlifetime_param = true; }
1138                                                                         }
1139                                                                         if !nonlifetime_param { t_gen_args = String::new(); }
1140                                                                         if takes_self {
1141                                                                                 write!(w, "<native{} as {}<{}>>::{}(unsafe {{ &mut *(this_arg as *mut native{}) }}, ", ident, $trait_path, t_gen_args, $m.sig.ident, ident).unwrap();
1142                                                                         } else {
1143                                                                                 write!(w, "<native{} as {}<{}>>::{}(", ident, $trait_path, t_gen_args, $m.sig.ident).unwrap();
1144                                                                         }
1145
1146                                                                         let mut real_type = "".to_string();
1147                                                                         match &$m.sig.output {
1148                                                                                 syn::ReturnType::Type(_, rtype) => {
1149                                                                                         if let Some(mut remaining_path) = first_seg_self(&*rtype) {
1150                                                                                                 if let Some(associated_seg) = get_single_remaining_path_seg(&mut remaining_path) {
1151                                                                                                         real_type = format!("{}", impl_associated_types.get(associated_seg).unwrap());
1152                                                                                                 }
1153                                                                                         }
1154                                                                                 },
1155                                                                                 _ => {},
1156                                                                         }
1157                                                                         write_method_call_params(w, &$trait_meth.sig, "", &mut trait_resolver, Some(&meth_gen_types), &real_type, false);
1158                                                                 }
1159                                                                 write!(w, "\n}}\n").unwrap();
1160                                                                 if let syn::ReturnType::Type(_, rtype) = &$m.sig.output {
1161                                                                         if let syn::Type::Reference(r) = &**rtype {
1162                                                                                 assert_eq!($m.sig.inputs.len(), 1); // Must only take self
1163                                                                                 writeln!(w, "extern \"C\" fn {}_{}_set_{}(trait_self_arg: &{}) {{", ident, $trait.ident, $m.sig.ident, $trait.ident).unwrap();
1164                                                                                 writeln!(w, "\t// This is a bit race-y in the general case, but for our specific use-cases today, we're safe").unwrap();
1165                                                                                 writeln!(w, "\t// Specifically, we must ensure that the first time we're called it can never be in parallel").unwrap();
1166                                                                                 write!(w, "\tif ").unwrap();
1167                                                                                 $types.write_empty_rust_val_check(Some(&meth_gen_types), w, &*r.elem, &format!("trait_self_arg.{}", $m.sig.ident));
1168                                                                                 writeln!(w, " {{").unwrap();
1169                                                                                 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();
1170                                                                                 writeln!(w, "\t}}").unwrap();
1171                                                                                 writeln!(w, "}}").unwrap();
1172                                                                         }
1173                                                                 }
1174                                                         }
1175                                                 }
1176
1177                                                 'impl_item_loop: for trait_item in trait_obj.items.iter() {
1178                                                         match trait_item {
1179                                                                 syn::TraitItem::Method(meth) => {
1180                                                                         for item in i.items.iter() {
1181                                                                                 match item {
1182                                                                                         syn::ImplItem::Method(m) => {
1183                                                                                                 if meth.sig.ident == m.sig.ident {
1184                                                                                                         impl_meth!(m, meth, full_trait_path, trait_obj, "", types);
1185                                                                                                         continue 'impl_item_loop;
1186                                                                                                 }
1187                                                                                         },
1188                                                                                         syn::ImplItem::Type(_) => {},
1189                                                                                         _ => unimplemented!(),
1190                                                                                 }
1191                                                                         }
1192                                                                         assert!(meth.default.is_some());
1193                                                                         let old_gen_types = gen_types;
1194                                                                         gen_types = GenericTypes::new(Some(resolved_path.clone()));
1195                                                                         impl_meth!(meth, meth, full_trait_path, trait_obj, "", &mut trait_resolver);
1196                                                                         gen_types = old_gen_types;
1197                                                                 },
1198                                                                 _ => {},
1199                                                         }
1200                                                 }
1201                                                 if requires_clone {
1202                                                         writeln!(w, "extern \"C\" fn {}_{}_cloned(new_obj: &mut crate::{}) {{", trait_obj.ident, ident, full_trait_path).unwrap();
1203                                                         writeln!(w, "\tnew_obj.this_arg = {}_clone_void(new_obj.this_arg);", ident).unwrap();
1204                                                         writeln!(w, "\tnew_obj.free = Some({}_free_void);", ident).unwrap();
1205                                                         walk_supertraits!(trait_obj, Some(&types), (
1206                                                                 (s, t, _) => {
1207                                                                         if types.crate_types.traits.get(s).is_some() {
1208                                                                                 assert!(!types.is_clonable(s)); // We don't currently support cloning with a clonable supertrait
1209                                                                                 writeln!(w, "\tnew_obj.{}.this_arg = new_obj.this_arg;", t).unwrap();
1210                                                                                 writeln!(w, "\tnew_obj.{}.free = None;", t).unwrap();
1211                                                                         }
1212                                                                 }
1213                                                         ) );
1214                                                         writeln!(w, "}}").unwrap();
1215                                                 }
1216                                                 write!(w, "\n").unwrap();
1217                                                 return;
1218                                         }
1219                                         if is_type_unconstructable(&resolved_path) {
1220                                                 // Don't bother exposing trait implementations for objects which cannot be
1221                                                 // instantiated.
1222                                                 return;
1223                                         }
1224                                         if path_matches_nongeneric(&trait_path.1, &["From"]) {
1225                                         } else if path_matches_nongeneric(&trait_path.1, &["Default"]) {
1226                                                 writeln!(w, "/// Creates a \"default\" {}. See struct and individual field documentaiton for details on which values are used.", ident).unwrap();
1227                                                 write!(w, "#[must_use]\n#[no_mangle]\npub extern \"C\" fn {}_default() -> {} {{\n", ident, ident).unwrap();
1228                                                 write!(w, "\t{} {{ inner: ObjOps::heap_alloc(Default::default()), is_owned: true }}\n", ident).unwrap();
1229                                                 write!(w, "}}\n").unwrap();
1230                                         } else if path_matches_nongeneric(&trait_path.1, &["core", "cmp", "PartialEq"]) {
1231                                         } else if path_matches_nongeneric(&trait_path.1, &["core", "cmp", "Eq"]) {
1232                                                 writeln!(w, "/// Checks if two {}s contain equal inner contents.", ident).unwrap();
1233                                                 writeln!(w, "/// This ignores pointers and is_owned flags and looks at the values in fields.").unwrap();
1234                                                 if types.c_type_has_inner_from_path(&resolved_path) {
1235                                                         writeln!(w, "/// Two objects with NULL inner values will be considered \"equal\" here.").unwrap();
1236                                                 }
1237                                                 write!(w, "#[no_mangle]\npub extern \"C\" fn {}_eq(a: &{}, b: &{}) -> bool {{\n", ident, ident, ident).unwrap();
1238                                                 if types.c_type_has_inner_from_path(&resolved_path) {
1239                                                         write!(w, "\tif a.inner == b.inner {{ return true; }}\n").unwrap();
1240                                                         write!(w, "\tif a.inner.is_null() || b.inner.is_null() {{ return false; }}\n").unwrap();
1241                                                 }
1242
1243                                                 let path = &p.path;
1244                                                 let ref_type: syn::Type = syn::parse_quote!(&#path);
1245                                                 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");
1246
1247                                                 write!(w, "\tif ").unwrap();
1248                                                 types.write_from_c_conversion_prefix(w, &ref_type, Some(&gen_types));
1249                                                 write!(w, "a").unwrap();
1250                                                 types.write_from_c_conversion_suffix(w, &ref_type, Some(&gen_types));
1251                                                 write!(w, " == ").unwrap();
1252                                                 types.write_from_c_conversion_prefix(w, &ref_type, Some(&gen_types));
1253                                                 write!(w, "b").unwrap();
1254                                                 types.write_from_c_conversion_suffix(w, &ref_type, Some(&gen_types));
1255
1256                                                 writeln!(w, " {{ true }} else {{ false }}\n}}").unwrap();
1257                                         } else if path_matches_nongeneric(&trait_path.1, &["core", "hash", "Hash"]) {
1258                                                 writeln!(w, "/// Checks if two {}s contain equal inner contents.", ident).unwrap();
1259                                                 write!(w, "#[no_mangle]\npub extern \"C\" fn {}_hash(o: &{}) -> u64 {{\n", ident, ident).unwrap();
1260                                                 if types.c_type_has_inner_from_path(&resolved_path) {
1261                                                         write!(w, "\tif o.inner.is_null() {{ return 0; }}\n").unwrap();
1262                                                 }
1263
1264                                                 let path = &p.path;
1265                                                 let ref_type: syn::Type = syn::parse_quote!(&#path);
1266                                                 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");
1267
1268                                                 writeln!(w, "\t// Note that we'd love to use alloc::collections::hash_map::DefaultHasher but it's not in core").unwrap();
1269                                                 writeln!(w, "\t#[allow(deprecated)]").unwrap();
1270                                                 writeln!(w, "\tlet mut hasher = core::hash::SipHasher::new();").unwrap();
1271                                                 write!(w, "\tcore::hash::Hash::hash(").unwrap();
1272                                                 types.write_from_c_conversion_prefix(w, &ref_type, Some(&gen_types));
1273                                                 write!(w, "o").unwrap();
1274                                                 types.write_from_c_conversion_suffix(w, &ref_type, Some(&gen_types));
1275                                                 writeln!(w, ", &mut hasher);").unwrap();
1276                                                 writeln!(w, "\tcore::hash::Hasher::finish(&hasher)\n}}").unwrap();
1277                                         } else if (path_matches_nongeneric(&trait_path.1, &["core", "clone", "Clone"]) || path_matches_nongeneric(&trait_path.1, &["Clone"])) &&
1278                                                         types.c_type_has_inner_from_path(&resolved_path) {
1279                                                 writeln!(w, "impl Clone for {} {{", ident).unwrap();
1280                                                 writeln!(w, "\tfn clone(&self) -> Self {{").unwrap();
1281                                                 writeln!(w, "\t\tSelf {{").unwrap();
1282                                                 writeln!(w, "\t\t\tinner: if <*mut native{}>::is_null(self.inner) {{ core::ptr::null_mut() }} else {{", ident).unwrap();
1283                                                 writeln!(w, "\t\t\t\tObjOps::heap_alloc(unsafe {{ &*ObjOps::untweak_ptr(self.inner) }}.clone()) }},").unwrap();
1284                                                 writeln!(w, "\t\t\tis_owned: true,").unwrap();
1285                                                 writeln!(w, "\t\t}}\n\t}}\n}}").unwrap();
1286                                                 writeln!(w, "#[allow(unused)]").unwrap();
1287                                                 writeln!(w, "/// Used only if an object of this type is returned as a trait impl by a method").unwrap();
1288                                                 writeln!(w, "pub(crate) extern \"C\" fn {}_clone_void(this_ptr: *const c_void) -> *mut c_void {{", ident).unwrap();
1289                                                 writeln!(w, "\tBox::into_raw(Box::new(unsafe {{ (*(this_ptr as *mut native{})).clone() }})) as *mut c_void", ident).unwrap();
1290                                                 writeln!(w, "}}").unwrap();
1291                                                 writeln!(w, "#[no_mangle]").unwrap();
1292                                                 writeln!(w, "/// Creates a copy of the {}", ident).unwrap();
1293                                                 writeln!(w, "pub extern \"C\" fn {}_clone(orig: &{}) -> {} {{", ident, ident, ident).unwrap();
1294                                                 writeln!(w, "\torig.clone()").unwrap();
1295                                                 writeln!(w, "}}").unwrap();
1296                                         } else if path_matches_nongeneric(&trait_path.1, &["FromStr"]) {
1297                                                 let mut err_opt = None;
1298                                                 for item in i.items.iter() {
1299                                                         match item {
1300                                                                 syn::ImplItem::Type(ty) if format!("{}", ty.ident) == "Err" => {
1301                                                                         err_opt = Some(&ty.ty);
1302                                                                 },
1303                                                                 _ => {}
1304                                                         }
1305                                                 }
1306                                                 let err_ty = err_opt.unwrap();
1307                                                 if let Some(container) = types.get_c_mangled_container_type(vec![&*i.self_ty, &err_ty], Some(&gen_types), "Result") {
1308                                                         writeln!(w, "#[no_mangle]").unwrap();
1309                                                         writeln!(w, "/// Read a {} object from a string", ident).unwrap();
1310                                                         writeln!(w, "pub extern \"C\" fn {}_from_str(s: crate::c_types::Str) -> {} {{", ident, container).unwrap();
1311                                                         writeln!(w, "\tmatch {}::from_str(s.into_str()) {{", resolved_path).unwrap();
1312
1313                                                         writeln!(w, "\t\tOk(r) => {{").unwrap();
1314                                                         let new_var = types.write_to_c_conversion_new_var(w, &format_ident!("r"), &*i.self_ty, Some(&gen_types), false);
1315                                                         write!(w, "\t\t\tcrate::c_types::CResultTempl::ok(\n\t\t\t\t").unwrap();
1316                                                         types.write_to_c_conversion_inline_prefix(w, &*i.self_ty, Some(&gen_types), false);
1317                                                         write!(w, "{}r", if new_var { "local_" } else { "" }).unwrap();
1318                                                         types.write_to_c_conversion_inline_suffix(w, &*i.self_ty, Some(&gen_types), false);
1319                                                         writeln!(w, "\n\t\t\t)\n\t\t}},").unwrap();
1320
1321                                                         writeln!(w, "\t\tErr(e) => {{").unwrap();
1322                                                         let new_var = types.write_to_c_conversion_new_var(w, &format_ident!("e"), &err_ty, Some(&gen_types), false);
1323                                                         write!(w, "\t\t\tcrate::c_types::CResultTempl::err(\n\t\t\t\t").unwrap();
1324                                                         types.write_to_c_conversion_inline_prefix(w, &err_ty, Some(&gen_types), false);
1325                                                         write!(w, "{}e", if new_var { "local_" } else { "" }).unwrap();
1326                                                         types.write_to_c_conversion_inline_suffix(w, &err_ty, Some(&gen_types), false);
1327                                                         writeln!(w, "\n\t\t\t)\n\t\t}},").unwrap();
1328
1329                                                         writeln!(w, "\t}}.into()\n}}").unwrap();
1330                                                 }
1331                                         } else if path_matches_nongeneric(&trait_path.1, &["Display"]) {
1332                                                 writeln!(w, "#[no_mangle]").unwrap();
1333                                                 writeln!(w, "/// Get the string representation of a {} object", ident).unwrap();
1334                                                 writeln!(w, "pub extern \"C\" fn {}_to_str(o: &crate::{}) -> Str {{", ident, resolved_path).unwrap();
1335
1336                                                 let self_ty = &i.self_ty;
1337                                                 let ref_type: syn::Type = syn::parse_quote!(&#self_ty);
1338                                                 let new_var = types.write_from_c_conversion_new_var(w, &format_ident!("o"), &ref_type, Some(&gen_types));
1339                                                 write!(w, "\talloc::format!(\"{{}}\", ").unwrap();
1340                                                 types.write_from_c_conversion_prefix(w, &ref_type, Some(&gen_types));
1341                                                 write!(w, "{}o", if new_var { "local_" } else { "" }).unwrap();
1342                                                 types.write_from_c_conversion_suffix(w, &ref_type, Some(&gen_types));
1343                                                 writeln!(w, ").into()").unwrap();
1344
1345                                                 writeln!(w, "}}").unwrap();
1346                                         } else {
1347                                                 //XXX: implement for other things like ToString
1348                                                 // If we have no generics, try a manual implementation:
1349                                                 maybe_convert_trait_impl(w, &trait_path.1, &*i.self_ty, types, &gen_types);
1350                                         }
1351                                 } else {
1352                                         let is_opaque = types.crate_types.opaques.contains_key(&resolved_path);
1353                                         let is_mirrored_enum = types.crate_types.mirrored_enums.contains_key(&resolved_path);
1354                                         for item in i.items.iter() {
1355                                                 match item {
1356                                                         syn::ImplItem::Method(m) => {
1357                                                                 if let syn::Visibility::Public(_) = m.vis {
1358                                                                         match export_status(&m.attrs) {
1359                                                                                 ExportStatus::Export => {},
1360                                                                                 ExportStatus::NoExport|ExportStatus::TestOnly => continue,
1361                                                                                 ExportStatus::NotImplementable => panic!("(C-not implementable) must only appear on traits"),
1362                                                                         }
1363                                                                         if m.sig.asyncness.is_some() { continue; }
1364                                                                         let mut meth_gen_types = gen_types.push_ctx();
1365                                                                         assert!(meth_gen_types.learn_generics(&m.sig.generics, types));
1366                                                                         if m.defaultness.is_some() { unimplemented!(); }
1367                                                                         writeln_fn_docs(w, &m.attrs, "", types, Some(&meth_gen_types), m.sig.inputs.iter(), &m.sig.output);
1368                                                                         if let syn::ReturnType::Type(_, _) = &m.sig.output {
1369                                                                                 writeln!(w, "#[must_use]").unwrap();
1370                                                                         }
1371                                                                         write!(w, "#[no_mangle]\npub extern \"C\" fn {}_{}(", ident, m.sig.ident).unwrap();
1372                                                                         let ret_type = format!("crate::{}", resolved_path);
1373                                                                         write_method_params(w, &m.sig, &ret_type, types, Some(&meth_gen_types), false, true);
1374                                                                         write!(w, " {{\n\t").unwrap();
1375                                                                         write_method_var_decl_body(w, &m.sig, "", types, Some(&meth_gen_types), false);
1376                                                                         let mut takes_self = false;
1377                                                                         let mut takes_mut_self = false;
1378                                                                         let mut takes_owned_self = false;
1379                                                                         for inp in m.sig.inputs.iter() {
1380                                                                                 if let syn::FnArg::Receiver(r) = inp {
1381                                                                                         takes_self = true;
1382                                                                                         if r.mutability.is_some() { takes_mut_self = true; }
1383                                                                                         if r.reference.is_none() { takes_owned_self = true; }
1384                                                                                 }
1385                                                                         }
1386                                                                         if !takes_mut_self && !takes_self {
1387                                                                                 write!(w, "{}::{}(", resolved_path, m.sig.ident).unwrap();
1388                                                                         } else {
1389                                                                                 if is_mirrored_enum {
1390                                                                                         write!(w, "this_arg.to_native().{}(", m.sig.ident).unwrap();
1391                                                                                 } else if is_opaque {
1392                                                                                         if takes_owned_self {
1393                                                                                                 write!(w, "(*unsafe {{ Box::from_raw(this_arg.take_inner()) }}).{}(", m.sig.ident).unwrap();
1394                                                                                         } else if takes_mut_self {
1395                                                                                                 write!(w, "unsafe {{ &mut (*ObjOps::untweak_ptr(this_arg.inner as *mut crate::{}::native{})) }}.{}(", rsplit_once(&resolved_path, "::").unwrap().0, ident, m.sig.ident).unwrap();
1396                                                                                         } else {
1397                                                                                                 write!(w, "unsafe {{ &*ObjOps::untweak_ptr(this_arg.inner) }}.{}(", m.sig.ident).unwrap();
1398                                                                                         }
1399                                                                                 } else {
1400                                                                                         unimplemented!();
1401                                                                                 }
1402                                                                         }
1403                                                                         write_method_call_params(w, &m.sig, "", types, Some(&meth_gen_types), &ret_type, false);
1404                                                                         writeln!(w, "\n}}\n").unwrap();
1405                                                                 }
1406                                                         },
1407                                                         _ => {},
1408                                                 }
1409                                         }
1410                                 }
1411                         } else if let Some(resolved_path) = types.maybe_resolve_ident(&ident) {
1412                                 create_alias_for_impl(resolved_path, i, types, move |aliased_impl, types| writeln_impl(w, w_uses, &aliased_impl, types));
1413                         } else {
1414                                 eprintln!("Not implementing anything for {} due to no-resolve (probably the type isn't pub)", ident);
1415                         }
1416                 }
1417         }
1418 }
1419
1420 fn create_alias_for_impl<F: FnMut(syn::ItemImpl, &mut TypeResolver)>(resolved_path: String, i: &syn::ItemImpl, types: &mut TypeResolver, mut callback: F) {
1421         if let Some(aliases) = types.crate_types.reverse_alias_map.get(&resolved_path).cloned() {
1422                 let mut gen_types = Some(GenericTypes::new(Some(resolved_path.clone())));
1423                 if !gen_types.as_mut().unwrap().learn_generics(&i.generics, types) {
1424                         gen_types = None;
1425                 }
1426                 let alias_module = rsplit_once(&resolved_path, "::").unwrap().0;
1427
1428                 'alias_impls: for (alias_resolved, arguments) in aliases {
1429                         let mut new_ty_generics = Vec::new();
1430                         let mut new_ty_bounds = Vec::new();
1431                         let mut need_generics = false;
1432
1433                         let alias_resolver_override;
1434                         let alias_resolver = if alias_module != types.module_path {
1435                                 alias_resolver_override = ImportResolver::new(types.types.crate_name, &types.crate_types.lib_ast,
1436                                         alias_module, &types.crate_types.lib_ast.modules.get(alias_module).unwrap().items);
1437                                 &alias_resolver_override
1438                         } else { &types.types };
1439                         let mut where_clause = syn::WhereClause { where_token: syn::Token![where](Span::call_site()),
1440                                 predicates: syn::punctuated::Punctuated::new()
1441                         };
1442                         for (idx, gen) in i.generics.params.iter().enumerate() {
1443                                 match gen {
1444                                         syn::GenericParam::Type(type_param) => {
1445                                                 'bounds_check: for bound in type_param.bounds.iter() {
1446                                                         if let syn::TypeParamBound::Trait(trait_bound) = bound {
1447                                                                 if let syn::PathArguments::AngleBracketed(ref t) = &arguments {
1448                                                                         assert!(idx < t.args.len());
1449                                                                         if let syn::GenericArgument::Type(syn::Type::Path(p)) = &t.args[idx] {
1450                                                                                 let generic_bound = types.maybe_resolve_path(&trait_bound.path, None)
1451                                                                                         .unwrap_or_else(|| format!("{}::{}", types.module_path, single_ident_generic_path_to_ident(&trait_bound.path).unwrap()));
1452
1453                                                                                 if let Some(generic_arg) = alias_resolver.maybe_resolve_path(&p.path, None) {
1454                                                                                         new_ty_generics.push((type_param.ident.clone(), syn::Type::Path(p.clone())));
1455                                                                                         if let Some(traits_impld) = types.crate_types.trait_impls.get(&generic_arg) {
1456                                                                                                 for trait_impld in traits_impld {
1457                                                                                                         if *trait_impld == generic_bound { continue 'bounds_check; }
1458                                                                                                 }
1459                                                                                                 eprintln!("struct {}'s generic arg {} didn't match bound {}", alias_resolved, generic_arg, generic_bound);
1460                                                                                                 continue 'alias_impls;
1461                                                                                         } else {
1462                                                                                                 eprintln!("struct {}'s generic arg {} didn't match bound {}", alias_resolved, generic_arg, generic_bound);
1463                                                                                                 continue 'alias_impls;
1464                                                                                         }
1465                                                                                 } else if gen_types.is_some() {
1466                                                                                         let resp =  types.maybe_resolve_path(&p.path, gen_types.as_ref());
1467                                                                                         if generic_bound == "core::ops::Deref" && resp.is_some() {
1468                                                                                                 new_ty_bounds.push((type_param.ident.clone(),
1469                                                                                                         string_path_to_syn_path("core::ops::Deref")));
1470                                                                                                 let mut bounds = syn::punctuated::Punctuated::new();
1471                                                                                                 bounds.push(syn::TypeParamBound::Trait(syn::TraitBound {
1472                                                                                                         paren_token: None,
1473                                                                                                         modifier: syn::TraitBoundModifier::None,
1474                                                                                                         lifetimes: None,
1475                                                                                                         path: string_path_to_syn_path(&types.resolve_path(&p.path, gen_types.as_ref())),
1476                                                                                                 }));
1477                                                                                                 let mut path = string_path_to_syn_path(&format!("{}::Target", type_param.ident));
1478                                                                                                 path.leading_colon = None;
1479                                                                                                 where_clause.predicates.push(syn::WherePredicate::Type(syn::PredicateType {
1480                                                                                                         lifetimes: None,
1481                                                                                                         bounded_ty: syn::Type::Path(syn::TypePath { qself: None, path }),
1482                                                                                                         colon_token: syn::Token![:](Span::call_site()),
1483                                                                                                         bounds,
1484                                                                                                 }));
1485                                                                                         } else {
1486                                                                                                 new_ty_generics.push((type_param.ident.clone(),
1487                                                                                                         gen_types.as_ref().resolve_type(&syn::Type::Path(p.clone())).clone()));
1488                                                                                         }
1489                                                                                         need_generics = true;
1490                                                                                 } else {
1491                                                                                         unimplemented!();
1492                                                                                 }
1493                                                                         } else { unimplemented!(); }
1494                                                                 } else { unimplemented!(); }
1495                                                         } else { unimplemented!(); }
1496                                                 }
1497                                         },
1498                                         syn::GenericParam::Lifetime(_) => {},
1499                                         syn::GenericParam::Const(_) => unimplemented!(),
1500                                 }
1501                         }
1502                         let mut params = syn::punctuated::Punctuated::new();
1503                         let alias = string_path_to_syn_path(&alias_resolved);
1504                         let real_aliased =
1505                                 if need_generics {
1506                                         let alias_generics = types.crate_types.opaques.get(&alias_resolved).unwrap().1;
1507
1508                                         // If we need generics on the alias, create impl generic bounds...
1509                                         assert_eq!(new_ty_generics.len() + new_ty_bounds.len(), i.generics.params.len());
1510                                         let mut args = syn::punctuated::Punctuated::new();
1511                                         for (ident, param) in new_ty_generics.drain(..) {
1512                                                 // TODO: We blindly assume that generics in the type alias and
1513                                                 // the aliased type have the same names, which we really shouldn't.
1514                                                 if alias_generics.params.iter().any(|generic|
1515                                                         if let syn::GenericParam::Type(t) = generic { t.ident == ident } else { false })
1516                                                 {
1517                                                         args.push(parse_quote!(#ident));
1518                                                 }
1519                                                 params.push(syn::GenericParam::Type(syn::TypeParam {
1520                                                         attrs: Vec::new(),
1521                                                         ident,
1522                                                         colon_token: None,
1523                                                         bounds: syn::punctuated::Punctuated::new(),
1524                                                         eq_token: Some(syn::token::Eq(Span::call_site())),
1525                                                         default: Some(param),
1526                                                 }));
1527                                         }
1528                                         for (ident, param) in new_ty_bounds.drain(..) {
1529                                                 // TODO: We blindly assume that generics in the type alias and
1530                                                 // the aliased type have the same names, which we really shouldn't.
1531                                                 if alias_generics.params.iter().any(|generic|
1532                                                         if let syn::GenericParam::Type(t) = generic { t.ident == ident } else { false })
1533                                                 {
1534                                                         args.push(parse_quote!(#ident));
1535                                                 }
1536                                                 params.push(syn::GenericParam::Type(syn::TypeParam {
1537                                                         attrs: Vec::new(),
1538                                                         ident,
1539                                                         colon_token: Some(syn::token::Colon(Span::call_site())),
1540                                                         bounds: syn::punctuated::Punctuated::from_iter(
1541                                                                 Some(syn::TypeParamBound::Trait(syn::TraitBound {
1542                                                                         path: param, paren_token: None, lifetimes: None,
1543                                                                         modifier: syn::TraitBoundModifier::None,
1544                                                                 }))
1545                                                         ),
1546                                                         eq_token: None,
1547                                                         default: None,
1548                                                 }));
1549                                         }
1550                                         // ... and swap the last segment of the impl self_ty to use the generic bounds.
1551                                         let mut res = alias.clone();
1552                                         res.segments.last_mut().unwrap().arguments = syn::PathArguments::AngleBracketed(syn::AngleBracketedGenericArguments {
1553                                                 colon2_token: None,
1554                                                 lt_token: syn::token::Lt(Span::call_site()),
1555                                                 args,
1556                                                 gt_token: syn::token::Gt(Span::call_site()),
1557                                         });
1558                                         res
1559                                 } else { alias.clone() };
1560                         callback(syn::ItemImpl {
1561                                 attrs: i.attrs.clone(),
1562                                 brace_token: syn::token::Brace(Span::call_site()),
1563                                 defaultness: None,
1564                                 generics: syn::Generics {
1565                                         lt_token: None,
1566                                         params,
1567                                         gt_token: None,
1568                                         where_clause: Some(where_clause),
1569                                 },
1570                                 impl_token: syn::Token![impl](Span::call_site()),
1571                                 items: i.items.clone(),
1572                                 self_ty: Box::new(syn::Type::Path(syn::TypePath { qself: None, path: real_aliased })),
1573                                 trait_: i.trait_.clone(),
1574                                 unsafety: None,
1575                         }, types);
1576                 }
1577         } else {
1578                 eprintln!("Not implementing anything for {} due to it being marked not exported", resolved_path);
1579         }
1580 }
1581
1582 /// Replaces upper case charachters with underscore followed by lower case except the first
1583 /// charachter and repeated upper case characthers (which are only made lower case).
1584 fn camel_to_snake_case(camel: &str) -> String {
1585         let mut res = "".to_string();
1586         let mut last_upper = -1;
1587         for (idx, c) in camel.chars().enumerate() {
1588                 if c.is_uppercase() {
1589                         if last_upper != idx as isize - 1 { res.push('_'); }
1590                         res.push(c.to_lowercase().next().unwrap());
1591                         last_upper = idx as isize;
1592                 } else {
1593                         res.push(c);
1594                 }
1595         }
1596         res
1597 }
1598
1599
1600 /// Print a mapping of an enum. If all of the enum's fields are C-mapped in some form (or the enum
1601 /// is unitary), we generate an equivalent enum with all types replaced with their C mapped
1602 /// versions followed by conversion functions which map between the Rust version and the C mapped
1603 /// version.
1604 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) {
1605         match export_status(&e.attrs) {
1606                 ExportStatus::Export => {},
1607                 ExportStatus::NoExport|ExportStatus::TestOnly => return,
1608                 ExportStatus::NotImplementable => panic!("(C-not implementable) must only appear on traits"),
1609         }
1610
1611         if is_enum_opaque(e) {
1612                 eprintln!("Skipping enum {} as it contains non-unit fields", e.ident);
1613                 writeln_opaque(w, &e.ident, &format!("{}", e.ident), &e.generics, &e.attrs, types, extra_headers, cpp_headers);
1614                 return;
1615         }
1616         writeln_docs(w, &e.attrs, "");
1617
1618         let mut gen_types = GenericTypes::new(None);
1619         assert!(gen_types.learn_generics(&e.generics, types));
1620
1621         let mut needs_free = false;
1622         let mut constr = Vec::new();
1623         let mut is_clonable = true;
1624
1625         for var in e.variants.iter() {
1626                 if let syn::Fields::Named(fields) = &var.fields {
1627                         needs_free = true;
1628                         for field in fields.named.iter() {
1629                                 if export_status(&field.attrs) == ExportStatus::TestOnly { continue; }
1630
1631                                 let mut ty_checks = Vec::new();
1632                                 types.write_c_type(&mut ty_checks, &field.ty, Some(&gen_types), false);
1633                                 if !types.is_clonable(&String::from_utf8(ty_checks).unwrap()) {
1634                                         is_clonable = false;
1635                                 }
1636                         }
1637                 } else if let syn::Fields::Unnamed(fields) = &var.fields {
1638                         for field in fields.unnamed.iter() {
1639                                 let mut ty_checks = Vec::new();
1640                                 types.write_c_type(&mut ty_checks, &field.ty, Some(&gen_types), false);
1641                                 let ty = String::from_utf8(ty_checks).unwrap();
1642                                 if ty != "" && !types.is_clonable(&ty) {
1643                                         is_clonable = false;
1644                                 }
1645                         }
1646                 }
1647         }
1648
1649         if is_clonable {
1650                 writeln!(w, "#[derive(Clone)]").unwrap();
1651                 types.crate_types.set_clonable(format!("{}::{}", types.module_path, e.ident));
1652         }
1653         writeln!(w, "#[must_use]\n#[repr(C)]\npub enum {} {{", e.ident).unwrap();
1654         for var in e.variants.iter() {
1655                 assert_eq!(export_status(&var.attrs), ExportStatus::Export); // We can't partially-export a mirrored enum
1656                 writeln_docs(w, &var.attrs, "\t");
1657                 write!(w, "\t{}", var.ident).unwrap();
1658                 writeln!(&mut constr, "#[no_mangle]\n/// Utility method to constructs a new {}-variant {}", var.ident, e.ident).unwrap();
1659                 let constr_name = camel_to_snake_case(&format!("{}", var.ident));
1660                 write!(&mut constr, "pub extern \"C\" fn {}_{}(", e.ident, constr_name).unwrap();
1661                 let mut empty_tuple_variant = false;
1662                 if let syn::Fields::Named(fields) = &var.fields {
1663                         needs_free = true;
1664                         writeln!(w, " {{").unwrap();
1665                         for (idx, field) in fields.named.iter().enumerate() {
1666                                 if export_status(&field.attrs) == ExportStatus::TestOnly { continue; }
1667                                 writeln_field_docs(w, &field.attrs, "\t\t", types, Some(&gen_types), &field.ty);
1668                                 write!(w, "\t\t{}: ", field.ident.as_ref().unwrap()).unwrap();
1669                                 write!(&mut constr, "{}{}: ", if idx != 0 { ", " } else { "" }, field.ident.as_ref().unwrap()).unwrap();
1670                                 types.write_c_type(w, &field.ty, Some(&gen_types), true);
1671                                 types.write_c_type(&mut constr, &field.ty, Some(&gen_types), true);
1672                                 writeln!(w, ",").unwrap();
1673                         }
1674                         write!(w, "\t}}").unwrap();
1675                 } else if let syn::Fields::Unnamed(fields) = &var.fields {
1676                         if fields.unnamed.len() == 1 {
1677                                 let mut empty_check = Vec::new();
1678                                 types.write_c_type(&mut empty_check, &fields.unnamed[0].ty, Some(&gen_types), true);
1679                                 if empty_check.is_empty() {
1680                                         empty_tuple_variant = true;
1681                                 }
1682                         }
1683                         if !empty_tuple_variant {
1684                                 needs_free = true;
1685                                 writeln!(w, "(").unwrap();
1686                                 for (idx, field) in fields.unnamed.iter().enumerate() {
1687                                         if export_status(&field.attrs) == ExportStatus::TestOnly { continue; }
1688                                         writeln_field_docs(w, &field.attrs, "\t\t", types, Some(&gen_types), &field.ty);
1689                                         write!(w, "\t\t").unwrap();
1690                                         types.write_c_type(w, &field.ty, Some(&gen_types), true);
1691
1692                                         write!(&mut constr, "{}: ", ('a' as u8 + idx as u8) as char).unwrap();
1693                                         types.write_c_type(&mut constr, &field.ty, Some(&gen_types), false);
1694                                         if idx != fields.unnamed.len() - 1 {
1695                                                 writeln!(w, ",").unwrap();
1696                                                 write!(&mut constr, ",").unwrap();
1697                                         }
1698                                 }
1699                                 write!(w, ")").unwrap();
1700                         }
1701                 }
1702                 if var.discriminant.is_some() { unimplemented!(); }
1703                 write!(&mut constr, ") -> {} {{\n\t{}::{}", e.ident, e.ident, var.ident).unwrap();
1704                 if let syn::Fields::Named(fields) = &var.fields {
1705                         writeln!(&mut constr, " {{").unwrap();
1706                         for field in fields.named.iter() {
1707                                 writeln!(&mut constr, "\t\t{},", field.ident.as_ref().unwrap()).unwrap();
1708                         }
1709                         writeln!(&mut constr, "\t}}").unwrap();
1710                 } else if let syn::Fields::Unnamed(fields) = &var.fields {
1711                         if !empty_tuple_variant {
1712                                 write!(&mut constr, "(").unwrap();
1713                                 for (idx, field) in fields.unnamed.iter().enumerate() {
1714                                         let mut ref_c_ty = Vec::new();
1715                                         let mut nonref_c_ty = Vec::new();
1716                                         types.write_c_type(&mut ref_c_ty, &field.ty, Some(&gen_types), false);
1717                                         types.write_c_type(&mut nonref_c_ty, &field.ty, Some(&gen_types), true);
1718
1719                                         if ref_c_ty != nonref_c_ty {
1720                                                 // We blindly assume references in field types are always opaque types, and
1721                                                 // print out an opaque reference -> owned reference conversion here.
1722                                                 write!(&mut constr, "{} {{ inner: {}.inner, is_owned: false }}, ", String::from_utf8(nonref_c_ty).unwrap(), ('a' as u8 + idx as u8) as char).unwrap();
1723                                         } else {
1724                                                 write!(&mut constr, "{}, ", ('a' as u8 + idx as u8) as char).unwrap();
1725                                         }
1726                                 }
1727                                 writeln!(&mut constr, ")").unwrap();
1728                         } else {
1729                                 writeln!(&mut constr, "").unwrap();
1730                         }
1731                 }
1732                 writeln!(&mut constr, "}}").unwrap();
1733                 writeln!(w, ",").unwrap();
1734         }
1735         writeln!(w, "}}\nuse {}::{} as {}Import;", types.module_path, e.ident, e.ident).unwrap();
1736         write!(w, "pub(crate) type native{} = {}Import", e.ident, e.ident).unwrap();
1737         maybe_write_generics(w, &e.generics, &syn::PathArguments::None, &types, true);
1738         writeln!(w, ";\n\nimpl {} {{", e.ident).unwrap();
1739
1740         macro_rules! write_conv {
1741                 ($fn_sig: expr, $to_c: expr, $ref: expr) => {
1742                         writeln!(w, "\t#[allow(unused)]\n\tpub(crate) fn {} {{\n\t\tmatch {} {{", $fn_sig, if $to_c { "native" } else { "self" }).unwrap();
1743                         for var in e.variants.iter() {
1744                                 write!(w, "\t\t\t{}{}::{} ", if $to_c { "native" } else { "" }, e.ident, var.ident).unwrap();
1745                                 let mut empty_tuple_variant = false;
1746                                 if let syn::Fields::Named(fields) = &var.fields {
1747                                         write!(w, "{{").unwrap();
1748                                         for field in fields.named.iter() {
1749                                                 if export_status(&field.attrs) == ExportStatus::TestOnly { continue; }
1750                                                 write!(w, "{}{}, ", if $ref { "ref " } else { "mut " }, field.ident.as_ref().unwrap()).unwrap();
1751                                         }
1752                                         write!(w, "}} ").unwrap();
1753                                 } else if let syn::Fields::Unnamed(fields) = &var.fields {
1754                                         if fields.unnamed.len() == 1 {
1755                                                 let mut empty_check = Vec::new();
1756                                                 types.write_c_type(&mut empty_check, &fields.unnamed[0].ty, Some(&gen_types), true);
1757                                                 if empty_check.is_empty() {
1758                                                         empty_tuple_variant = true;
1759                                                 }
1760                                         }
1761                                         if !empty_tuple_variant || $to_c {
1762                                                 write!(w, "(").unwrap();
1763                                                 for (idx, field) in fields.unnamed.iter().enumerate() {
1764                                                         if export_status(&field.attrs) == ExportStatus::TestOnly { continue; }
1765                                                         write!(w, "{}{}, ", if $ref { "ref " } else { "mut " }, ('a' as u8 + idx as u8) as char).unwrap();
1766                                                 }
1767                                                 write!(w, ") ").unwrap();
1768                                         }
1769                                 }
1770                                 write!(w, "=>").unwrap();
1771
1772                                 macro_rules! handle_field_a {
1773                                         ($field: expr, $field_ident: expr) => { {
1774                                                 if export_status(&$field.attrs) == ExportStatus::TestOnly { continue; }
1775                                                 let mut sink = ::std::io::sink();
1776                                                 let mut out: &mut dyn std::io::Write = if $ref { &mut sink } else { w };
1777                                                 let new_var = if $to_c {
1778                                                         types.write_to_c_conversion_new_var(&mut out, $field_ident, &$field.ty, Some(&gen_types), true)
1779                                                 } else {
1780                                                         types.write_from_c_conversion_new_var(&mut out, $field_ident, &$field.ty, Some(&gen_types))
1781                                                 };
1782                                                 if $ref || new_var {
1783                                                         if $ref {
1784                                                                 write!(w, "let mut {}_nonref = Clone::clone({});\n\t\t\t\t", $field_ident, $field_ident).unwrap();
1785                                                                 if new_var {
1786                                                                         let nonref_ident = format_ident!("{}_nonref", $field_ident);
1787                                                                         if $to_c {
1788                                                                                 types.write_to_c_conversion_new_var(w, &nonref_ident, &$field.ty, Some(&gen_types), true);
1789                                                                         } else {
1790                                                                                 types.write_from_c_conversion_new_var(w, &nonref_ident, &$field.ty, Some(&gen_types));
1791                                                                         }
1792                                                                         write!(w, "\n\t\t\t\t").unwrap();
1793                                                                 }
1794                                                         } else {
1795                                                                 write!(w, "\n\t\t\t\t").unwrap();
1796                                                         }
1797                                                 }
1798                                         } }
1799                                 }
1800                                 if let syn::Fields::Named(fields) = &var.fields {
1801                                         write!(w, " {{\n\t\t\t\t").unwrap();
1802                                         for field in fields.named.iter() {
1803                                                 handle_field_a!(field, field.ident.as_ref().unwrap());
1804                                         }
1805                                 } else if let syn::Fields::Unnamed(fields) = &var.fields {
1806                                         write!(w, " {{\n\t\t\t\t").unwrap();
1807                                         for (idx, field) in fields.unnamed.iter().enumerate() {
1808                                                 if !empty_tuple_variant {
1809                                                         handle_field_a!(field, &format_ident!("{}", ('a' as u8 + idx as u8) as char));
1810                                                 }
1811                                         }
1812                                 } else { write!(w, " ").unwrap(); }
1813
1814                                 write!(w, "{}{}::{}", if $to_c { "" } else { "native" }, e.ident, var.ident).unwrap();
1815
1816                                 macro_rules! handle_field_b {
1817                                         ($field: expr, $field_ident: expr) => { {
1818                                                 if export_status(&$field.attrs) == ExportStatus::TestOnly { continue; }
1819                                                 if $to_c {
1820                                                         types.write_to_c_conversion_inline_prefix(w, &$field.ty, Some(&gen_types), true);
1821                                                 } else {
1822                                                         types.write_from_c_conversion_prefix(w, &$field.ty, Some(&gen_types));
1823                                                 }
1824                                                 write!(w, "{}{}", $field_ident,
1825                                                         if $ref { "_nonref" } else { "" }).unwrap();
1826                                                 if $to_c {
1827                                                         types.write_to_c_conversion_inline_suffix(w, &$field.ty, Some(&gen_types), true);
1828                                                 } else {
1829                                                         types.write_from_c_conversion_suffix(w, &$field.ty, Some(&gen_types));
1830                                                 }
1831                                                 write!(w, ",").unwrap();
1832                                         } }
1833                                 }
1834
1835                                 if let syn::Fields::Named(fields) = &var.fields {
1836                                         write!(w, " {{").unwrap();
1837                                         for field in fields.named.iter() {
1838                                                 if export_status(&field.attrs) == ExportStatus::TestOnly { continue; }
1839                                                 write!(w, "\n\t\t\t\t\t{}: ", field.ident.as_ref().unwrap()).unwrap();
1840                                                 handle_field_b!(field, field.ident.as_ref().unwrap());
1841                                         }
1842                                         writeln!(w, "\n\t\t\t\t}}").unwrap();
1843                                         write!(w, "\t\t\t}}").unwrap();
1844                                 } else if let syn::Fields::Unnamed(fields) = &var.fields {
1845                                         if !empty_tuple_variant || !$to_c {
1846                                                 write!(w, " (").unwrap();
1847                                                 for (idx, field) in fields.unnamed.iter().enumerate() {
1848                                                         write!(w, "\n\t\t\t\t\t").unwrap();
1849                                                         handle_field_b!(field, &format_ident!("{}", ('a' as u8 + idx as u8) as char));
1850                                                 }
1851                                                 writeln!(w, "\n\t\t\t\t)").unwrap();
1852                                         }
1853                                         write!(w, "\t\t\t}}").unwrap();
1854                                 }
1855                                 writeln!(w, ",").unwrap();
1856                         }
1857                         writeln!(w, "\t\t}}\n\t}}").unwrap();
1858                 }
1859         }
1860
1861         if is_clonable {
1862                 write_conv!(format!("to_native(&self) -> native{}", e.ident), false, true);
1863         }
1864         write_conv!(format!("into_native(self) -> native{}", e.ident), false, false);
1865         if is_clonable {
1866                 write_conv!(format!("from_native(native: &native{}) -> Self", e.ident), true, true);
1867         }
1868         write_conv!(format!("native_into(native: native{}) -> Self", e.ident), true, false);
1869         writeln!(w, "}}").unwrap();
1870
1871         if needs_free {
1872                 writeln!(w, "/// Frees any resources used by the {}", e.ident).unwrap();
1873                 writeln!(w, "#[no_mangle]\npub extern \"C\" fn {}_free(this_ptr: {}) {{ }}", e.ident, e.ident).unwrap();
1874         }
1875         if is_clonable {
1876                 writeln!(w, "/// Creates a copy of the {}", e.ident).unwrap();
1877                 writeln!(w, "#[no_mangle]").unwrap();
1878                 writeln!(w, "pub extern \"C\" fn {}_clone(orig: &{}) -> {} {{", e.ident, e.ident, e.ident).unwrap();
1879                 writeln!(w, "\torig.clone()").unwrap();
1880                 writeln!(w, "}}").unwrap();
1881         }
1882         w.write_all(&constr).unwrap();
1883         write_cpp_wrapper(cpp_headers, &format!("{}", e.ident), needs_free, None);
1884 }
1885
1886 fn writeln_fn<'a, 'b, W: std::io::Write>(w: &mut W, f: &'a syn::ItemFn, types: &mut TypeResolver<'b, 'a>) {
1887         match export_status(&f.attrs) {
1888                 ExportStatus::Export => {},
1889                 ExportStatus::NoExport|ExportStatus::TestOnly => return,
1890                 ExportStatus::NotImplementable => panic!("(C-not implementable) must only appear on traits"),
1891         }
1892         let mut gen_types = GenericTypes::new(None);
1893         if !gen_types.learn_generics(&f.sig.generics, types) { return; }
1894
1895         writeln_fn_docs(w, &f.attrs, "", types, Some(&gen_types), f.sig.inputs.iter(), &f.sig.output);
1896
1897         write!(w, "#[no_mangle]\npub extern \"C\" fn {}(", f.sig.ident).unwrap();
1898
1899
1900         write_method_params(w, &f.sig, "", types, Some(&gen_types), false, true);
1901         write!(w, " {{\n\t").unwrap();
1902         write_method_var_decl_body(w, &f.sig, "", types, Some(&gen_types), false);
1903         write!(w, "{}::{}", types.module_path, f.sig.ident).unwrap();
1904
1905         let mut function_generic_args = Vec::new();
1906         maybe_write_generics(&mut function_generic_args, &f.sig.generics, &syn::PathArguments::None, types, true);
1907         if !function_generic_args.is_empty() {
1908                 write!(w, "::{}", String::from_utf8(function_generic_args).unwrap()).unwrap();
1909         }
1910         write!(w, "(").unwrap();
1911
1912         write_method_call_params(w, &f.sig, "", types, Some(&gen_types), "", false);
1913         writeln!(w, "\n}}\n").unwrap();
1914 }
1915
1916 // ********************************
1917 // *** File/Crate Walking Logic ***
1918 // ********************************
1919
1920 fn convert_priv_mod<'a, 'b: 'a, W: std::io::Write>(w: &mut W, w_uses: &mut HashSet<String, NonRandomHash>, libast: &'b FullLibraryAST, crate_types: &CrateTypes<'b>, out_dir: &str, mod_path: &str, module: &'b syn::ItemMod) {
1921         // We want to ignore all items declared in this module (as they are not pub), but we still need
1922         // to give the ImportResolver any use statements, so we copy them here.
1923         let mut use_items = Vec::new();
1924         for item in module.content.as_ref().unwrap().1.iter() {
1925                 if let syn::Item::Use(_) = item {
1926                         use_items.push(item);
1927                 }
1928         }
1929         let import_resolver = ImportResolver::from_borrowed_items(mod_path.splitn(2, "::").next().unwrap(), libast, mod_path, &use_items);
1930         let mut types = TypeResolver::new(mod_path, import_resolver, crate_types);
1931
1932         writeln!(w, "mod {} {{\n{}", module.ident, DEFAULT_IMPORTS).unwrap();
1933         for item in module.content.as_ref().unwrap().1.iter() {
1934                 match item {
1935                         syn::Item::Mod(m) => convert_priv_mod(w, w_uses, libast, crate_types, out_dir, &format!("{}::{}", mod_path, module.ident), m),
1936                         syn::Item::Impl(i) => {
1937                                 writeln_impl(w, w_uses, i, &mut types);
1938                         },
1939                         _ => {},
1940                 }
1941         }
1942         writeln!(w, "}}").unwrap();
1943 }
1944
1945 /// Do the Real Work of mapping an original file to C-callable wrappers. Creates a new file at
1946 /// `out_path` and fills it with wrapper structs/functions to allow calling the things in the AST
1947 /// at `module` from C.
1948 fn convert_file<'a, 'b>(libast: &'a FullLibraryAST, crate_types: &CrateTypes<'a>, out_dir: &str, header_file: &mut File, cpp_header_file: &mut File) {
1949         for (module, astmod) in libast.modules.iter() {
1950                 let orig_crate = module.splitn(2, "::").next().unwrap();
1951                 let ASTModule { ref attrs, ref items, ref submods } = astmod;
1952                 assert_eq!(export_status(&attrs), ExportStatus::Export);
1953
1954                 let new_file_path = if submods.is_empty() {
1955                         format!("{}/{}.rs", out_dir, module.replace("::", "/"))
1956                 } else if module != "" {
1957                         format!("{}/{}/mod.rs", out_dir, module.replace("::", "/"))
1958                 } else {
1959                         format!("{}/lib.rs", out_dir)
1960                 };
1961                 let _ = std::fs::create_dir((&new_file_path.as_ref() as &std::path::Path).parent().unwrap());
1962                 let mut out = std::fs::OpenOptions::new().write(true).create(true).truncate(true)
1963                         .open(new_file_path).expect("Unable to open new src file");
1964                 let mut out_uses = HashSet::default();
1965
1966                 writeln!(out, "// This file is Copyright its original authors, visible in version control").unwrap();
1967                 writeln!(out, "// history and in the source files from which this was generated.").unwrap();
1968                 writeln!(out, "//").unwrap();
1969                 writeln!(out, "// This file is licensed under the license available in the LICENSE or LICENSE.md").unwrap();
1970                 writeln!(out, "// file in the root of this repository or, if no such file exists, the same").unwrap();
1971                 writeln!(out, "// license as that which applies to the original source files from which this").unwrap();
1972                 writeln!(out, "// source was automatically generated.").unwrap();
1973                 writeln!(out, "").unwrap();
1974
1975                 writeln_docs(&mut out, &attrs, "");
1976
1977                 if module == "" {
1978                         // Special-case the top-level lib.rs with various lint allows and a pointer to the c_types
1979                         // and bitcoin hand-written modules.
1980                         writeln!(out, "//! C Bindings").unwrap();
1981                         writeln!(out, "#![allow(unknown_lints)]").unwrap();
1982                         writeln!(out, "#![allow(non_camel_case_types)]").unwrap();
1983                         writeln!(out, "#![allow(non_snake_case)]").unwrap();
1984                         writeln!(out, "#![allow(unused_imports)]").unwrap();
1985                         writeln!(out, "#![allow(unused_variables)]").unwrap();
1986                         writeln!(out, "#![allow(unused_mut)]").unwrap();
1987                         writeln!(out, "#![allow(unused_parens)]").unwrap();
1988                         writeln!(out, "#![allow(unused_unsafe)]").unwrap();
1989                         writeln!(out, "#![allow(unused_braces)]").unwrap();
1990                         // TODO: We need to map deny(missing_docs) in the source crate(s)
1991                         //writeln!(out, "#![deny(missing_docs)]").unwrap();
1992
1993                         writeln!(out, "#![cfg_attr(not(feature = \"std\"), no_std)]").unwrap();
1994                         writeln!(out, "#[cfg(not(any(feature = \"std\", feature = \"no-std\")))]").unwrap();
1995                         writeln!(out, "compile_error!(\"at least one of the `std` or `no-std` features must be enabled\");").unwrap();
1996                         writeln!(out, "extern crate alloc;").unwrap();
1997
1998                         writeln!(out, "pub mod version;").unwrap();
1999                         writeln!(out, "pub mod c_types;").unwrap();
2000                         writeln!(out, "pub mod bitcoin;").unwrap();
2001                 } else {
2002                         writeln!(out, "{}", DEFAULT_IMPORTS).unwrap();
2003                 }
2004
2005                 for m in submods {
2006                         writeln!(out, "pub mod {};", m).unwrap();
2007                 }
2008
2009                 eprintln!("Converting {} entries...", module);
2010
2011                 let import_resolver = ImportResolver::new(orig_crate, libast, module, items);
2012                 let mut type_resolver = TypeResolver::new(module, import_resolver, crate_types);
2013
2014                 for item in items.iter() {
2015                         match item {
2016                                 syn::Item::Use(_) => {}, // Handled above
2017                                 syn::Item::Static(_) => {},
2018                                 syn::Item::Enum(e) => {
2019                                         if let syn::Visibility::Public(_) = e.vis {
2020                                                 writeln_enum(&mut out, &e, &mut type_resolver, header_file, cpp_header_file);
2021                                         }
2022                                 },
2023                                 syn::Item::Impl(i) => {
2024                                         writeln_impl(&mut out, &mut out_uses, &i, &mut type_resolver);
2025                                 },
2026                                 syn::Item::Struct(s) => {
2027                                         if let syn::Visibility::Public(_) = s.vis {
2028                                                 writeln_struct(&mut out, &s, &mut type_resolver, header_file, cpp_header_file);
2029                                         }
2030                                 },
2031                                 syn::Item::Trait(t) => {
2032                                         if let syn::Visibility::Public(_) = t.vis {
2033                                                 writeln_trait(&mut out, &t, &mut type_resolver, header_file, cpp_header_file);
2034                                         }
2035                                 },
2036                                 syn::Item::Mod(m) => {
2037                                         convert_priv_mod(&mut out, &mut out_uses, libast, crate_types, out_dir, &format!("{}::{}", module, m.ident), m);
2038                                 },
2039                                 syn::Item::Const(c) => {
2040                                         // Re-export any primitive-type constants.
2041                                         if let syn::Visibility::Public(_) = c.vis {
2042                                                 if let syn::Type::Path(p) = &*c.ty {
2043                                                         let resolved_path = type_resolver.resolve_path(&p.path, None);
2044                                                         if type_resolver.is_primitive(&resolved_path) {
2045                                                                 writeln_field_docs(&mut out, &c.attrs, "", &mut type_resolver, None, &*c.ty);
2046                                                                 writeln!(out, "\n#[no_mangle]").unwrap();
2047                                                                 writeln!(out, "pub static {}: {} = {}::{};", c.ident, resolved_path, module, c.ident).unwrap();
2048                                                         }
2049                                                 }
2050                                         }
2051                                 },
2052                                 syn::Item::Type(t) => {
2053                                         if let syn::Visibility::Public(_) = t.vis {
2054                                                 match export_status(&t.attrs) {
2055                                                         ExportStatus::Export => {},
2056                                                         ExportStatus::NoExport|ExportStatus::TestOnly => continue,
2057                                                         ExportStatus::NotImplementable => panic!("(C-not implementable) must only appear on traits"),
2058                                                 }
2059
2060                                                 match &*t.ty {
2061                                                         syn::Type::Path(p) => {
2062                                                                 let real_ty = type_resolver.resolve_path(&p.path, None);
2063                                                                 let real_generic_bounds = type_resolver.crate_types.opaques.get(&real_ty).map(|t| t.1).or(
2064                                                                         type_resolver.crate_types.priv_structs.get(&real_ty).map(|r| *r)).unwrap();
2065                                                                 let mut resolved_generics = t.generics.clone();
2066
2067                                                                 // Assume blindly that the bounds in the struct definition where
2068                                                                 // clause matches any equivalent bounds on the type alias.
2069                                                                 assert!(resolved_generics.where_clause.is_none());
2070                                                                 resolved_generics.where_clause = real_generic_bounds.where_clause.clone();
2071
2072                                                                 if let syn::PathArguments::AngleBracketed(real_generics) = &p.path.segments.last().unwrap().arguments {
2073                                                                         for (real_idx, real_param) in real_generics.args.iter().enumerate() {
2074                                                                                 if let syn::GenericArgument::Type(syn::Type::Path(real_param_path)) = real_param {
2075                                                                                         for param in resolved_generics.params.iter_mut() {
2076                                                                                                 if let syn::GenericParam::Type(type_param) = param {
2077                                                                                                         if Some(&type_param.ident) == real_param_path.path.get_ident() {
2078                                                                                                                 if let syn::GenericParam::Type(real_type_param) = &real_generic_bounds.params[real_idx] {
2079                                                                                                                         type_param.bounds = real_type_param.bounds.clone();
2080                                                                                                                         type_param.default = real_type_param.default.clone();
2081
2082                                                                                                                 }
2083                                                                                                         }
2084                                                                                                 }
2085                                                                                         }
2086                                                                                 }
2087                                                                         }
2088                                                                 }
2089
2090                                                                 writeln_opaque(&mut out, &t.ident, &format!("{}", t.ident), &resolved_generics, &t.attrs, &type_resolver, header_file, cpp_header_file)},
2091                                                         _ => {}
2092                                                 }
2093                                         }
2094                                 },
2095                                 syn::Item::Fn(f) => {
2096                                         if let syn::Visibility::Public(_) = f.vis {
2097                                                 writeln_fn(&mut out, &f, &mut type_resolver);
2098                                         }
2099                                 },
2100                                 syn::Item::Macro(_) => {},
2101                                 syn::Item::Verbatim(_) => {},
2102                                 syn::Item::ExternCrate(_) => {},
2103                                 _ => unimplemented!(),
2104                         }
2105                 }
2106
2107                 for use_stmt in out_uses {
2108                         writeln!(out, "{}", use_stmt).unwrap();
2109                 }
2110
2111                 out.flush().unwrap();
2112         }
2113 }
2114
2115
2116 /// Walk the FullLibraryAST, determining if impl aliases need to be marked cloneable.
2117 fn walk_ast_second_pass<'a>(ast_storage: &'a FullLibraryAST, crate_types: &CrateTypes<'a>) {
2118         for (module, astmod) in ast_storage.modules.iter() {
2119                 let orig_crate = module.splitn(2, "::").next().unwrap();
2120                 let ASTModule { ref attrs, ref items, .. } = astmod;
2121                 assert_eq!(export_status(&attrs), ExportStatus::Export);
2122
2123                 let import_resolver = ImportResolver::new(orig_crate, ast_storage, module, items);
2124                 let mut types = TypeResolver::new(module, import_resolver, crate_types);
2125
2126                 for item in items.iter() {
2127                         match item {
2128                                 syn::Item::Impl(i) => {
2129                                         match export_status(&i.attrs) {
2130                                                 ExportStatus::Export => {},
2131                                                 ExportStatus::NoExport|ExportStatus::TestOnly => continue,
2132                                                 ExportStatus::NotImplementable => panic!("(C-not implementable) must only appear on traits"),
2133                                         }
2134                                         if let Some(trait_path) = i.trait_.as_ref() {
2135                                                 if path_matches_nongeneric(&trait_path.1, &["core", "clone", "Clone"]) ||
2136                                                    path_matches_nongeneric(&trait_path.1, &["Clone"])
2137                                                 {
2138                                                         if let &syn::Type::Path(ref p) = &*i.self_ty {
2139                                                                 if let Some(resolved_path) = types.maybe_resolve_path(&p.path, None) {
2140                                                                         create_alias_for_impl(resolved_path, i, &mut types, |aliased_impl, types| {
2141                                                                                 if let &syn::Type::Path(ref p) = &*aliased_impl.self_ty {
2142                                                                                         if let Some(resolved_aliased_path) = types.maybe_resolve_path(&p.path, None) {
2143                                                                                                 crate_types.set_clonable("crate::".to_owned() + &resolved_aliased_path);
2144                                                                                         }
2145                                                                                 }
2146                                                                         });
2147                                                                 }
2148                                                         }
2149                                                 }
2150                                         }
2151                                 }
2152                                 _ => {}
2153                         }
2154                 }
2155         }
2156 }
2157
2158 fn walk_private_mod<'a>(ast_storage: &'a FullLibraryAST, orig_crate: &str, module: String, items: &'a syn::ItemMod, crate_types: &mut CrateTypes<'a>) {
2159         let import_resolver = ImportResolver::new(orig_crate, ast_storage, &module, &items.content.as_ref().unwrap().1);
2160         for item in items.content.as_ref().unwrap().1.iter() {
2161                 match item {
2162                         syn::Item::Mod(m) => walk_private_mod(ast_storage, orig_crate, format!("{}::{}", module, m.ident), m, crate_types),
2163                         syn::Item::Impl(i) => {
2164                                 if let &syn::Type::Path(ref p) = &*i.self_ty {
2165                                         if let Some(trait_path) = i.trait_.as_ref() {
2166                                                 if let Some(tp) = import_resolver.maybe_resolve_path(&trait_path.1, None) {
2167                                                         if let Some(sp) = import_resolver.maybe_resolve_path(&p.path, None) {
2168                                                                 match crate_types.trait_impls.entry(sp) {
2169                                                                         hash_map::Entry::Occupied(mut e) => { e.get_mut().push(tp); },
2170                                                                         hash_map::Entry::Vacant(e) => { e.insert(vec![tp]); },
2171                                                                 }
2172                                                         }
2173                                                 }
2174                                         }
2175                                 }
2176                         },
2177                         _ => {},
2178                 }
2179         }
2180 }
2181
2182 /// Walk the FullLibraryAST, deciding how things will be mapped and adding tracking to CrateTypes.
2183 fn walk_ast_first_pass<'a>(ast_storage: &'a FullLibraryAST, crate_types: &mut CrateTypes<'a>) {
2184         for (module, astmod) in ast_storage.modules.iter() {
2185                 let ASTModule { ref attrs, ref items, submods: _ } = astmod;
2186                 assert_eq!(export_status(&attrs), ExportStatus::Export);
2187                 let orig_crate = module.splitn(2, "::").next().unwrap();
2188                 let import_resolver = ImportResolver::new(orig_crate, ast_storage, module, items);
2189
2190                 for item in items.iter() {
2191                         match item {
2192                                 syn::Item::Struct(s) => {
2193                                         if let syn::Visibility::Public(_) = s.vis {
2194                                                 let struct_path = format!("{}::{}", module, s.ident);
2195                                                 match export_status(&s.attrs) {
2196                                                         ExportStatus::Export => {},
2197                                                         ExportStatus::NoExport|ExportStatus::TestOnly => {
2198                                                                 crate_types.priv_structs.insert(struct_path, &s.generics);
2199                                                                 continue
2200                                                         },
2201                                                         ExportStatus::NotImplementable => panic!("(C-not implementable) must only appear on traits"),
2202                                                 }
2203                                                 crate_types.opaques.insert(struct_path, (&s.ident, &s.generics));
2204                                         }
2205                                 },
2206                                 syn::Item::Trait(t) => {
2207                                         if let syn::Visibility::Public(_) = t.vis {
2208                                                 match export_status(&t.attrs) {
2209                                                         ExportStatus::Export|ExportStatus::NotImplementable => {},
2210                                                         ExportStatus::NoExport|ExportStatus::TestOnly => continue,
2211                                                 }
2212                                                 let trait_path = format!("{}::{}", module, t.ident);
2213                                                 walk_supertraits!(t, None, (
2214                                                         ("Clone", _, _) => {
2215                                                                 crate_types.set_clonable("crate::".to_owned() + &trait_path);
2216                                                         },
2217                                                         (_, _, _) => {}
2218                                                 ) );
2219                                                 crate_types.traits.insert(trait_path, &t);
2220                                         }
2221                                 },
2222                                 syn::Item::Type(t) => {
2223                                         if let syn::Visibility::Public(_) = t.vis {
2224                                                 match export_status(&t.attrs) {
2225                                                         ExportStatus::Export => {},
2226                                                         ExportStatus::NoExport|ExportStatus::TestOnly => continue,
2227                                                         ExportStatus::NotImplementable => panic!("(C-not implementable) must only appear on traits"),
2228                                                 }
2229                                                 let type_path = format!("{}::{}", module, t.ident);
2230                                                 match &*t.ty {
2231                                                         syn::Type::Path(p) => {
2232                                                                 // If its a path with no generics, assume we don't map the aliased type and map it opaque
2233                                                                 let args_obj = p.path.segments.last().unwrap().arguments.clone();
2234                                                                 match crate_types.reverse_alias_map.entry(import_resolver.maybe_resolve_path(&p.path, None).unwrap()) {
2235                                                                         hash_map::Entry::Occupied(mut e) => { e.get_mut().push((type_path.clone(), args_obj)); },
2236                                                                         hash_map::Entry::Vacant(e) => { e.insert(vec![(type_path.clone(), args_obj)]); },
2237                                                                 }
2238
2239                                                                 crate_types.opaques.insert(type_path, (&t.ident, &t.generics));
2240                                                         },
2241                                                         _ => {
2242                                                                 crate_types.type_aliases.insert(type_path, import_resolver.resolve_imported_refs((*t.ty).clone()));
2243                                                         }
2244                                                 }
2245                                         }
2246                                 },
2247                                 syn::Item::Enum(e) if is_enum_opaque(e) => {
2248                                         if let syn::Visibility::Public(_) = e.vis {
2249                                                 match export_status(&e.attrs) {
2250                                                         ExportStatus::Export => {},
2251                                                         ExportStatus::NoExport|ExportStatus::TestOnly => continue,
2252                                                         ExportStatus::NotImplementable => panic!("(C-not implementable) must only appear on traits"),
2253                                                 }
2254                                                 let enum_path = format!("{}::{}", module, e.ident);
2255                                                 crate_types.opaques.insert(enum_path, (&e.ident, &e.generics));
2256                                         }
2257                                 },
2258                                 syn::Item::Enum(e) => {
2259                                         if let syn::Visibility::Public(_) = e.vis {
2260                                                 match export_status(&e.attrs) {
2261                                                         ExportStatus::Export => {},
2262                                                         ExportStatus::NoExport|ExportStatus::TestOnly => continue,
2263                                                         ExportStatus::NotImplementable => panic!("(C-not implementable) must only appear on traits"),
2264                                                 }
2265                                                 let enum_path = format!("{}::{}", module, e.ident);
2266                                                 crate_types.mirrored_enums.insert(enum_path, &e);
2267                                         }
2268                                 },
2269                                 syn::Item::Impl(i) => {
2270                                         if let &syn::Type::Path(ref p) = &*i.self_ty {
2271                                                 if let Some(trait_path) = i.trait_.as_ref() {
2272                                                         if path_matches_nongeneric(&trait_path.1, &["core", "clone", "Clone"]) ||
2273                                                            path_matches_nongeneric(&trait_path.1, &["Clone"]) {
2274                                                                 if let Some(full_path) = import_resolver.maybe_resolve_path(&p.path, None) {
2275                                                                         crate_types.set_clonable("crate::".to_owned() + &full_path);
2276                                                                 }
2277                                                         }
2278                                                         if let Some(tp) = import_resolver.maybe_resolve_path(&trait_path.1, None) {
2279                                                                 if let Some(sp) = import_resolver.maybe_resolve_path(&p.path, None) {
2280                                                                         match crate_types.trait_impls.entry(sp) {
2281                                                                                 hash_map::Entry::Occupied(mut e) => { e.get_mut().push(tp); },
2282                                                                                 hash_map::Entry::Vacant(e) => { e.insert(vec![tp]); },
2283                                                                         }
2284                                                                 }
2285                                                         }
2286                                                 }
2287                                         }
2288                                 },
2289                                 syn::Item::Mod(m) => walk_private_mod(ast_storage, orig_crate, format!("{}::{}", module, m.ident), m, crate_types),
2290                                 _ => {},
2291                         }
2292                 }
2293         }
2294 }
2295
2296 fn main() {
2297         let args: Vec<String> = env::args().collect();
2298         if args.len() != 5 {
2299                 eprintln!("Usage: target/dir derived_templates.rs extra/includes.h extra/cpp/includes.hpp");
2300                 process::exit(1);
2301         }
2302
2303         let mut derived_templates = std::fs::OpenOptions::new().write(true).create(true).truncate(true)
2304                 .open(&args[2]).expect("Unable to open new header file");
2305         writeln!(&mut derived_templates, "{}", DEFAULT_IMPORTS).unwrap();
2306         let mut header_file = std::fs::OpenOptions::new().write(true).create(true).truncate(true)
2307                 .open(&args[3]).expect("Unable to open new header file");
2308         let mut cpp_header_file = std::fs::OpenOptions::new().write(true).create(true).truncate(true)
2309                 .open(&args[4]).expect("Unable to open new header file");
2310
2311         writeln!(header_file, "#if defined(__GNUC__)").unwrap();
2312         writeln!(header_file, "#define MUST_USE_STRUCT __attribute__((warn_unused))").unwrap();
2313         writeln!(header_file, "#define MUST_USE_RES __attribute__((warn_unused_result))").unwrap();
2314         writeln!(header_file, "#else").unwrap();
2315         writeln!(header_file, "#define MUST_USE_STRUCT").unwrap();
2316         writeln!(header_file, "#define MUST_USE_RES").unwrap();
2317         writeln!(header_file, "#endif").unwrap();
2318         writeln!(header_file, "#if defined(__clang__)").unwrap();
2319         writeln!(header_file, "#define NONNULL_PTR _Nonnull").unwrap();
2320         writeln!(header_file, "#else").unwrap();
2321         writeln!(header_file, "#define NONNULL_PTR").unwrap();
2322         writeln!(header_file, "#endif").unwrap();
2323         writeln!(cpp_header_file, "#include <string.h>\nnamespace LDK {{").unwrap();
2324
2325         // Write a few manually-defined types into the C++ header file
2326         write_cpp_wrapper(&mut cpp_header_file, "Str", true, None);
2327
2328         // First parse the full crate's ASTs, caching them so that we can hold references to the AST
2329         // objects in other datastructures:
2330         let mut lib_src = String::new();
2331         std::io::stdin().lock().read_to_string(&mut lib_src).unwrap();
2332         let lib_syntax = syn::parse_file(&lib_src).expect("Unable to parse file");
2333         let libast = FullLibraryAST::load_lib(lib_syntax);
2334
2335         // ...then walk the ASTs tracking what types we will map, and how, so that we can resolve them
2336         // when parsing other file ASTs...
2337         let mut libtypes = CrateTypes::new(&mut derived_templates, &libast);
2338         walk_ast_first_pass(&libast, &mut libtypes);
2339
2340         // ... using the generated data, determine a few additional fields, specifically which type
2341         // aliases are to be clone-able...
2342         walk_ast_second_pass(&libast, &libtypes);
2343
2344         // ... finally, do the actual file conversion/mapping, writing out types as we go.
2345         convert_file(&libast, &libtypes, &args[1], &mut header_file, &mut cpp_header_file);
2346
2347         // For container templates which we created while walking the crate, make sure we add C++
2348         // mapped types so that C++ users can utilize the auto-destructors available.
2349         for (ty, has_destructor) in libtypes.templates_defined.borrow().iter() {
2350                 write_cpp_wrapper(&mut cpp_header_file, ty, *has_destructor, None);
2351         }
2352         writeln!(cpp_header_file, "}}").unwrap();
2353
2354         header_file.flush().unwrap();
2355         cpp_header_file.flush().unwrap();
2356         derived_templates.flush().unwrap();
2357 }