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

   1 //! Converts a rust crate into a rust crate containing a number of C-exported wrapper functions and
   2 //! classes (which is exportable using cbindgen).
   3 //! In general, supports convering:
   4 //!  * structs as a pointer to the underlying type (either owned or not owned),
   5 //!  * traits as a void-ptr plus a jump table,
   6 //!  * enums as an equivalent enum with all the inner fields mapped to the mapped types,
   7 //!  * certain containers (tuples, slices, Vecs, Options, and Results currently) to a concrete
   8 //!    version of a defined container template.
   9 //!
  10 //! It also generates relevant memory-management functions and free-standing functions with
  11 //! parameters mapped.
  12
  13 use std::collections::{HashMap, HashSet};
  14 use std::env;
  15 use std::fs::File;
  16 use std::io::{Read, Write};
  17 use std::process;
  18
  19 use proc_macro2::{TokenTree, TokenStream, Span};
  20
  21 mod types;
  22 mod blocks;
  23 use types::*;
  24 use blocks::*;
  25
  26 // *************************************
  27 // *** Manually-expanded conversions ***
  28 // *************************************
  29
  30 /// Because we don't expand macros, any code that we need to generated based on their contents has
  31 /// to be completely manual. In this case its all just serialization, so its not too hard.
  32 fn convert_macro<W: std::io::Write>(w: &mut W, macro_path: &syn::Path, stream: &TokenStream, types: &TypeResolver) {
  33         assert_eq!(macro_path.segments.len(), 1);
  34         match &format!("{}", macro_path.segments.iter().next().unwrap().ident) as &str {
  35                 "impl_writeable" | "impl_writeable_len_match" => {
  36                         let struct_for = if let TokenTree::Ident(i) = stream.clone().into_iter().next().unwrap() { i } else { unimplemented!(); };
  37                         if let Some(s) = types.maybe_resolve_ident(&struct_for) {
  38                                 if !types.crate_types.opaques.get(&s).is_some() { return; }
  39                                 writeln!(w, "#[no_mangle]").unwrap();
  40                                 writeln!(w, "pub extern \"C\" fn {}_write(obj: &{}) -> crate::c_types::derived::CVec_u8Z {{", struct_for, struct_for).unwrap();
  41                                 writeln!(w, "\tcrate::c_types::serialize_obj(unsafe {{ &(*(*obj).inner) }})").unwrap();
  42                                 writeln!(w, "}}").unwrap();
  43                                 writeln!(w, "#[no_mangle]").unwrap();
  44                                 writeln!(w, "pub(crate) extern \"C\" fn {}_write_void(obj: *const c_void) -> crate::c_types::derived::CVec_u8Z {{", struct_for).unwrap();
  45                                 writeln!(w, "\tcrate::c_types::serialize_obj(unsafe {{ &*(obj as *const native{}) }})", struct_for).unwrap();
  46                                 writeln!(w, "}}").unwrap();
  47                                 writeln!(w, "#[no_mangle]").unwrap();
  48                                 writeln!(w, "pub extern \"C\" fn {}_read(ser: crate::c_types::u8slice) -> {} {{", struct_for, struct_for).unwrap();
  49                                 writeln!(w, "\tif let Ok(res) = crate::c_types::deserialize_obj(ser) {{").unwrap();
  50                                 writeln!(w, "\t\t{} {{ inner: Box::into_raw(Box::new(res)), is_owned: true }}", struct_for).unwrap();
  51                                 writeln!(w, "\t}} else {{").unwrap();
  52                                 writeln!(w, "\t\t{} {{ inner: std::ptr::null_mut(), is_owned: true }}", struct_for).unwrap();
  53                                 writeln!(w, "\t}}\n}}").unwrap();
  54                         }
  55                 },
  56                 _ => {},
  57         }
  58 }
  59
  60 /// Convert "impl trait_path for for_ty { .. }" for manually-mapped types (ie (de)serialization)
  61 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) {
  62         if let Some(t) = types.maybe_resolve_path(&trait_path, Some(generics)) {
  63                 let for_obj;
  64                 let full_obj_path;
  65                 let mut has_inner = false;
  66                 if let syn::Type::Path(ref p) = for_ty {
  67                         if let Some(ident) = single_ident_generic_path_to_ident(&p.path) {
  68                                 for_obj = format!("{}", ident);
  69                                 full_obj_path = for_obj.clone();
  70                                 has_inner = types.c_type_has_inner_from_path(&types.resolve_path(&p.path, Some(generics)));
  71                         } else { return; }
  72                 } else {
  73                         // We assume that anything that isn't a Path is somehow a generic that ends up in our
  74                         // derived-types module.
  75                         let mut for_obj_vec = Vec::new();
  76                         types.write_c_type(&mut for_obj_vec, for_ty, Some(generics), false);
  77                         full_obj_path = String::from_utf8(for_obj_vec).unwrap();
  78                         assert!(full_obj_path.starts_with(TypeResolver::generated_container_path()));
  79                         for_obj = full_obj_path[TypeResolver::generated_container_path().len() + 2..].into();
  80                 }
  81
  82                 match &t as &str {
  83                         "util::ser::Writeable" => {
  84                                 writeln!(w, "#[no_mangle]").unwrap();
  85                                 writeln!(w, "pub extern \"C\" fn {}_write(obj: &{}) -> crate::c_types::derived::CVec_u8Z {{", for_obj, full_obj_path).unwrap();
  86
  87                                 let ref_type = syn::Type::Reference(syn::TypeReference {
  88                                         and_token: syn::Token!(&)(Span::call_site()), lifetime: None, mutability: None,
  89                                         elem: Box::new(for_ty.clone()) });
  90                                 assert!(!types.write_from_c_conversion_new_var(w, &syn::Ident::new("obj", Span::call_site()), &ref_type, Some(generics)));
  91
  92                                 write!(w, "\tcrate::c_types::serialize_obj(").unwrap();
  93                                 types.write_from_c_conversion_prefix(w, &ref_type, Some(generics));
  94                                 write!(w, "unsafe {{ &*obj }}").unwrap();
  95                                 types.write_from_c_conversion_suffix(w, &ref_type, Some(generics));
  96                                 writeln!(w, ")").unwrap();
  97
  98                                 writeln!(w, "}}").unwrap();
  99                                 if has_inner {
 100                                         writeln!(w, "#[no_mangle]").unwrap();
 101                                         writeln!(w, "pub(crate) extern \"C\" fn {}_write_void(obj: *const c_void) -> crate::c_types::derived::CVec_u8Z {{", for_obj).unwrap();
 102                                         writeln!(w, "\tcrate::c_types::serialize_obj(unsafe {{ &*(obj as *const native{}) }})", for_obj).unwrap();
 103                                         writeln!(w, "}}").unwrap();
 104                                 }
 105                         },
 106                         "util::ser::Readable"|"util::ser::ReadableArgs" => {
 107                                 // Create the Result<Object, DecodeError> syn::Type
 108                                 let mut err_segs = syn::punctuated::Punctuated::new();
 109                                 err_segs.push(syn::PathSegment { ident: syn::Ident::new("ln", Span::call_site()), arguments: syn::PathArguments::None });
 110                                 err_segs.push(syn::PathSegment { ident: syn::Ident::new("msgs", Span::call_site()), arguments: syn::PathArguments::None });
 111                                 err_segs.push(syn::PathSegment { ident: syn::Ident::new("DecodeError", Span::call_site()), arguments: syn::PathArguments::None });
 112                                 let mut args = syn::punctuated::Punctuated::new();
 113                                 args.push(syn::GenericArgument::Type(for_ty.clone()));
 114                                 args.push(syn::GenericArgument::Type(syn::Type::Path(syn::TypePath {
 115                                         qself: None, path: syn::Path {
 116                                                 leading_colon: Some(syn::Token![::](Span::call_site())), segments: err_segs,
 117                                         }
 118                                 })));
 119                                 let mut res_segs = syn::punctuated::Punctuated::new();
 120                                 res_segs.push(syn::PathSegment {
 121                                         ident: syn::Ident::new("Result", Span::call_site()),
 122                                         arguments: syn::PathArguments::AngleBracketed(syn::AngleBracketedGenericArguments {
 123                                                 colon2_token: None, lt_token: syn::Token![<](Span::call_site()), args, gt_token: syn::Token![>](Span::call_site()),
 124                                         })
 125                                 });
 126                                 let res_ty = syn::Type::Path(syn::TypePath { qself: None, path: syn::Path {
 127                                         leading_colon: None, segments: res_segs } });
 128
 129                                 writeln!(w, "#[no_mangle]").unwrap();
 130                                 write!(w, "pub extern \"C\" fn {}_read(ser: crate::c_types::u8slice", for_obj).unwrap();
 131
 132                                 let mut arg_conv = Vec::new();
 133                                 if t == "util::ser::ReadableArgs" {
 134                                         write!(w, ", arg: ").unwrap();
 135                                         assert!(trait_path.leading_colon.is_none());
 136                                         let args_seg = trait_path.segments.iter().last().unwrap();
 137                                         assert_eq!(format!("{}", args_seg.ident), "ReadableArgs");
 138                                         if let syn::PathArguments::AngleBracketed(args) = &args_seg.arguments {
 139                                                 assert_eq!(args.args.len(), 1);
 140                                                 if let syn::GenericArgument::Type(args_ty) = args.args.iter().next().unwrap() {
 141                                                         types.write_c_type(w, args_ty, Some(generics), false);
 142
 143                                                         assert!(!types.write_from_c_conversion_new_var(&mut arg_conv, &syn::Ident::new("arg", Span::call_site()), &args_ty, Some(generics)));
 144
 145                                                         write!(&mut arg_conv, "\tlet arg_conv = ").unwrap();
 146                                                         types.write_from_c_conversion_prefix(&mut arg_conv, &args_ty, Some(generics));
 147                                                         write!(&mut arg_conv, "arg").unwrap();
 148                                                         types.write_from_c_conversion_suffix(&mut arg_conv, &args_ty, Some(generics));
 149                                                 } else { unreachable!(); }
 150                                         } else { unreachable!(); }
 151                                 }
 152                                 write!(w, ") -> ").unwrap();
 153                                 types.write_c_type(w, &res_ty, Some(generics), false);
 154                                 writeln!(w, " {{").unwrap();
 155
 156                                 if t == "util::ser::ReadableArgs" {
 157                                         w.write(&arg_conv).unwrap();
 158                                         write!(w, ";\n\tlet res: ").unwrap();
 159                                         // At least in one case we need type annotations here, so provide them.
 160                                         types.write_rust_type(w, Some(generics), &res_ty);
 161                                         writeln!(w, " = crate::c_types::deserialize_obj_arg(ser, arg_conv);").unwrap();
 162                                 } else {
 163                                         writeln!(w, "\tlet res = crate::c_types::deserialize_obj(ser);").unwrap();
 164                                 }
 165                                 write!(w, "\t").unwrap();
 166                                 if types.write_to_c_conversion_new_var(w, &syn::Ident::new("res", Span::call_site()), &res_ty, Some(generics), false) {
 167                                         write!(w, "\n\t").unwrap();
 168                                 }
 169                                 types.write_to_c_conversion_inline_prefix(w, &res_ty, Some(generics), false);
 170                                 write!(w, "res").unwrap();
 171                                 types.write_to_c_conversion_inline_suffix(w, &res_ty, Some(generics), false);
 172                                 writeln!(w, "\n}}").unwrap();
 173                         },
 174                         _ => {},
 175                 }
 176         }
 177 }
 178
 179 /// Convert "TraitA : TraitB" to a single function name and return type.
 180 ///
 181 /// This is (obviously) somewhat over-specialized and only useful for TraitB's that only require a
 182 /// single function (eg for serialization).
 183 fn convert_trait_impl_field(trait_path: &str) -> (String, &'static str) {
 184         match trait_path {
 185                 "util::ser::Writeable" => ("write".to_owned(), "crate::c_types::derived::CVec_u8Z"),
 186                 _ => unimplemented!(),
 187         }
 188 }
 189
 190 /// Companion to convert_trait_impl_field, write an assignment for the function defined by it for
 191 /// `for_obj` which implements the the trait at `trait_path`.
 192 fn write_trait_impl_field_assign<W: std::io::Write>(w: &mut W, trait_path: &str, for_obj: &syn::Ident) {
 193         match trait_path {
 194                 "util::ser::Writeable" => {
 195                         writeln!(w, "\t\twrite: {}_write_void,", for_obj).unwrap();
 196                 },
 197                 _ => unimplemented!(),
 198         }
 199 }
 200
 201 /// Write out the impl block for a defined trait struct which has a supertrait
 202 fn do_write_impl_trait<W: std::io::Write>(w: &mut W, trait_path: &str, trait_name: &syn::Ident, for_obj: &str) {
 203         match trait_path {
 204                 "util::events::MessageSendEventsProvider" => {
 205                         writeln!(w, "impl lightning::{} for {} {{", trait_path, for_obj).unwrap();
 206                         writeln!(w, "\tfn get_and_clear_pending_msg_events(&self) -> Vec<lightning::util::events::MessageSendEvent> {{").unwrap();
 207                         writeln!(w, "\t\t<crate::{} as lightning::{}>::get_and_clear_pending_msg_events(&self.{})", trait_path, trait_path, trait_name).unwrap();
 208                         writeln!(w, "\t}}\n}}").unwrap();
 209                 },
 210                 "util::ser::Writeable" => {
 211                         writeln!(w, "impl lightning::{} for {} {{", trait_path, for_obj).unwrap();
 212                         writeln!(w, "\tfn write<W: lightning::util::ser::Writer>(&self, w: &mut W) -> Result<(), ::std::io::Error> {{").unwrap();
 213                         writeln!(w, "\t\tlet vec = (self.write)(self.this_arg);").unwrap();
 214                         writeln!(w, "\t\tw.write_all(vec.as_slice())").unwrap();
 215                         writeln!(w, "\t}}\n}}").unwrap();
 216                 },
 217                 _ => panic!(),
 218         }
 219 }
 220
 221 // *******************************
 222 // *** Per-Type Printing Logic ***
 223 // *******************************
 224
 225 macro_rules! walk_supertraits { ($t: expr, $types: expr, ($( $pat: pat => $e: expr),*) ) => { {
 226         if $t.colon_token.is_some() {
 227                 for st in $t.supertraits.iter() {
 228                         match st {
 229                                 syn::TypeParamBound::Trait(supertrait) => {
 230                                         if supertrait.paren_token.is_some() || supertrait.lifetimes.is_some() {
 231                                                 unimplemented!();
 232                                         }
 233                                         // First try to resolve path to find in-crate traits, but if that doesn't work
 234                                         // assume its a prelude trait (eg Clone, etc) and just use the single ident.
 235                                         let types_opt: Option<&TypeResolver> = $types;
 236                                         if let Some(types) = types_opt {
 237                                                 if let Some(path) = types.maybe_resolve_path(&supertrait.path, None) {
 238                                                         match (&path as &str, &supertrait.path.segments.iter().last().unwrap().ident) {
 239                                                                 $( $pat => $e, )*
 240                                                         }
 241                                                         continue;
 242                                                 }
 243                                         }
 244                                         if let Some(ident) = supertrait.path.get_ident() {
 245                                                 match (&format!("{}", ident) as &str, &ident) {
 246                                                         $( $pat => $e, )*
 247                                                 }
 248                                         } else if types_opt.is_some() {
 249                                                 panic!("Supertrait unresolvable and not single-ident");
 250                                         }
 251                                 },
 252                                 syn::TypeParamBound::Lifetime(_) => unimplemented!(),
 253                         }
 254                 }
 255         }
 256 } } }
 257
 258 /// Prints a C-mapped trait object containing a void pointer and a jump table for each function in
 259 /// the original trait.
 260 /// Implements the native Rust trait and relevant parent traits for the new C-mapped trait.
 261 ///
 262 /// Finally, implements Deref<MappedTrait> for MappedTrait which allows its use in types which need
 263 /// a concrete Deref to the Rust trait.
 264 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) {
 265         let trait_name = format!("{}", t.ident);
 266         match export_status(&t.attrs) {
 267                 ExportStatus::Export => {},
 268                 ExportStatus::NoExport|ExportStatus::TestOnly => return,
 269         }
 270         writeln_docs(w, &t.attrs, "");
 271
 272         let mut gen_types = GenericTypes::new();
 273         assert!(gen_types.learn_generics(&t.generics, types));
 274         gen_types.learn_associated_types(&t, types);
 275
 276         writeln!(w, "#[repr(C)]\npub struct {} {{", trait_name).unwrap();
 277         writeln!(w, "\tpub this_arg: *mut c_void,").unwrap();
 278         let mut generated_fields = Vec::new(); // Every field's name except this_arg, used in Clone generation
 279         for item in t.items.iter() {
 280                 match item {
 281                         &syn::TraitItem::Method(ref m) => {
 282                                 match export_status(&m.attrs) {
 283                                         ExportStatus::NoExport => {
 284                                                 // NoExport in this context means we'll hit an unimplemented!() at runtime,
 285                                                 // so bail out.
 286                                                 unimplemented!();
 287                                         },
 288                                         ExportStatus::Export => {},
 289                                         ExportStatus::TestOnly => continue,
 290                                 }
 291                                 if m.default.is_some() { unimplemented!(); }
 292
 293                                 gen_types.push_ctx();
 294                                 assert!(gen_types.learn_generics(&m.sig.generics, types));
 295
 296                                 writeln_docs(w, &m.attrs, "\t");
 297
 298                                 if let syn::ReturnType::Type(_, rtype) = &m.sig.output {
 299                                         if let syn::Type::Reference(r) = &**rtype {
 300                                                 // We have to do quite a dance for trait functions which return references
 301                                                 // - they ultimately require us to have a native Rust object stored inside
 302                                                 // our concrete trait to return a reference to. However, users may wish to
 303                                                 // update the value to be returned each time the function is called (or, to
 304                                                 // make C copies of Rust impls equivalent, we have to be able to).
 305                                                 //
 306                                                 // Thus, we store a copy of the C-mapped type (which is just a pointer to
 307                                                 // the Rust type and a flag to indicate whether deallocation needs to
 308                                                 // happen) as well as provide an Option<>al function pointer which is
 309                                                 // called when the trait method is called which allows updating on the fly.
 310                                                 write!(w, "\tpub {}: ", m.sig.ident).unwrap();
 311                                                 generated_fields.push(format!("{}", m.sig.ident));
 312                                                 types.write_c_type(w, &*r.elem, Some(&gen_types), false);
 313                                                 writeln!(w, ",").unwrap();
 314                                                 writeln!(w, "\t/// Fill in the {} field as a reference to it will be given to Rust after this returns", m.sig.ident).unwrap();
 315                                                 writeln!(w, "\t/// Note that this takes a pointer to this object, not the this_ptr like other methods do").unwrap();
 316                                                 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();
 317                                                 writeln!(w, "\tpub set_{}: Option<extern \"C\" fn(&{})>,", m.sig.ident, trait_name).unwrap();
 318                                                 generated_fields.push(format!("set_{}", m.sig.ident));
 319                                                 // Note that cbindgen will now generate
 320                                                 // typedef struct Thing {..., set_thing: (const Thing*), ...} Thing;
 321                                                 // which does not compile since Thing is not defined before it is used.
 322                                                 writeln!(extra_headers, "struct LDK{};", trait_name).unwrap();
 323                                                 writeln!(extra_headers, "typedef struct LDK{} LDK{};", trait_name, trait_name).unwrap();
 324                                                 gen_types.pop_ctx();
 325                                                 continue;
 326                                         }
 327                                         // Sadly, this currently doesn't do what we want, but it should be easy to get
 328                                         // cbindgen to support it. See https://github.com/eqrion/cbindgen/issues/531
 329                                         writeln!(w, "\t#[must_use]").unwrap();
 330                                 }
 331
 332                                 write!(w, "\tpub {}: extern \"C\" fn (", m.sig.ident).unwrap();
 333                                 generated_fields.push(format!("{}", m.sig.ident));
 334                                 write_method_params(w, &m.sig, "c_void", types, Some(&gen_types), true, false);
 335                                 writeln!(w, ",").unwrap();
 336
 337                                 gen_types.pop_ctx();
 338                         },
 339                         &syn::TraitItem::Type(_) => {},
 340                         _ => unimplemented!(),
 341                 }
 342         }
 343         // Add functions which may be required for supertrait implementations.
 344         walk_supertraits!(t, Some(&types), (
 345                 ("Clone", _) => {
 346                         writeln!(w, "\tpub clone: Option<extern \"C\" fn (this_arg: *const c_void) -> *mut c_void>,").unwrap();
 347                         generated_fields.push("clone".to_owned());
 348                 },
 349                 ("std::cmp::Eq", _) => {
 350                         writeln!(w, "\tpub eq: extern \"C\" fn (this_arg: *const c_void, other_arg: &{}) -> bool,", trait_name).unwrap();
 351                         writeln!(extra_headers, "typedef struct LDK{} LDK{};", trait_name, trait_name).unwrap();
 352                         generated_fields.push("eq".to_owned());
 353                 },
 354                 ("std::hash::Hash", _) => {
 355                         writeln!(w, "\tpub hash: extern \"C\" fn (this_arg: *const c_void) -> u64,").unwrap();
 356                         generated_fields.push("hash".to_owned());
 357                 },
 358                 ("Send", _) => {}, ("Sync", _) => {},
 359                 (s, i) => {
 360                         generated_fields.push(if types.crate_types.traits.get(s).is_none() {
 361                                 let (name, ret) = convert_trait_impl_field(s);
 362                                 writeln!(w, "\tpub {}: extern \"C\" fn (this_arg: *const c_void) -> {},", name, ret).unwrap();
 363                                 name
 364                         } else {
 365                                 // For in-crate supertraits, just store a C-mapped copy of the supertrait as a member.
 366                                 writeln!(w, "\tpub {}: crate::{},", i, s).unwrap();
 367                                 format!("{}", i)
 368                         });
 369                 }
 370         ) );
 371         writeln!(w, "\tpub free: Option<extern \"C\" fn(this_arg: *mut c_void)>,").unwrap();
 372         generated_fields.push("free".to_owned());
 373         writeln!(w, "}}").unwrap();
 374         // Implement supertraits for the C-mapped struct.
 375         walk_supertraits!(t, Some(&types), (
 376                 ("Send", _) => writeln!(w, "unsafe impl Send for {} {{}}", trait_name).unwrap(),
 377                 ("Sync", _) => writeln!(w, "unsafe impl Sync for {} {{}}", trait_name).unwrap(),
 378                 ("std::cmp::Eq", _) => {
 379                         writeln!(w, "impl std::cmp::Eq for {} {{}}", trait_name).unwrap();
 380                         writeln!(w, "impl std::cmp::PartialEq for {} {{", trait_name).unwrap();
 381                         writeln!(w, "\tfn eq(&self, o: &Self) -> bool {{ (self.eq)(self.this_arg, o) }}\n}}").unwrap();
 382                 },
 383                 ("std::hash::Hash", _) => {
 384                         writeln!(w, "impl std::hash::Hash for {} {{", trait_name).unwrap();
 385                         writeln!(w, "\tfn hash<H: std::hash::Hasher>(&self, hasher: &mut H) {{ hasher.write_u64((self.hash)(self.this_arg)) }}\n}}").unwrap();
 386                 },
 387                 ("Clone", _) => {
 388                         writeln!(w, "#[no_mangle]").unwrap();
 389                         writeln!(w, "pub extern \"C\" fn {}_clone(orig: &{}) -> {} {{", trait_name, trait_name, trait_name).unwrap();
 390                         writeln!(w, "\t{} {{", trait_name).unwrap();
 391                         writeln!(w, "\t\tthis_arg: if let Some(f) = orig.clone {{ (f)(orig.this_arg) }} else {{ orig.this_arg }},").unwrap();
 392                         for field in generated_fields.iter() {
 393                                 writeln!(w, "\t\t{}: orig.{}.clone(),", field, field).unwrap();
 394                         }
 395                         writeln!(w, "\t}}\n}}").unwrap();
 396                         writeln!(w, "impl Clone for {} {{", trait_name).unwrap();
 397                         writeln!(w, "\tfn clone(&self) -> Self {{").unwrap();
 398                         writeln!(w, "\t\t{}_clone(self)", trait_name).unwrap();
 399                         writeln!(w, "\t}}\n}}").unwrap();
 400                 },
 401                 (s, i) => {
 402                         do_write_impl_trait(w, s, i, &trait_name);
 403                 }
 404         ) );
 405
 406         // Finally, implement the original Rust trait for the newly created mapped trait.
 407         writeln!(w, "\nuse {}::{}::{} as rust{};", types.orig_crate, types.module_path, t.ident, trait_name).unwrap();
 408         write!(w, "impl rust{}", t.ident).unwrap();
 409         maybe_write_generics(w, &t.generics, types, false);
 410         writeln!(w, " for {} {{", trait_name).unwrap();
 411         for item in t.items.iter() {
 412                 match item {
 413                         syn::TraitItem::Method(m) => {
 414                                 if let ExportStatus::TestOnly = export_status(&m.attrs) { continue; }
 415                                 if m.default.is_some() { unimplemented!(); }
 416                                 if m.sig.constness.is_some() || m.sig.asyncness.is_some() || m.sig.unsafety.is_some() ||
 417                                                 m.sig.abi.is_some() || m.sig.variadic.is_some() {
 418                                         unimplemented!();
 419                                 }
 420                                 gen_types.push_ctx();
 421                                 assert!(gen_types.learn_generics(&m.sig.generics, types));
 422                                 write!(w, "\tfn {}", m.sig.ident).unwrap();
 423                                 types.write_rust_generic_param(w, Some(&gen_types), m.sig.generics.params.iter());
 424                                 write!(w, "(").unwrap();
 425                                 for inp in m.sig.inputs.iter() {
 426                                         match inp {
 427                                                 syn::FnArg::Receiver(recv) => {
 428                                                         if !recv.attrs.is_empty() || recv.reference.is_none() { unimplemented!(); }
 429                                                         write!(w, "&").unwrap();
 430                                                         if let Some(lft) = &recv.reference.as_ref().unwrap().1 {
 431                                                                 write!(w, "'{} ", lft.ident).unwrap();
 432                                                         }
 433                                                         if recv.mutability.is_some() {
 434                                                                 write!(w, "mut self").unwrap();
 435                                                         } else {
 436                                                                 write!(w, "self").unwrap();
 437                                                         }
 438                                                 },
 439                                                 syn::FnArg::Typed(arg) => {
 440                                                         if !arg.attrs.is_empty() { unimplemented!(); }
 441                                                         match &*arg.pat {
 442                                                                 syn::Pat::Ident(ident) => {
 443                                                                         if !ident.attrs.is_empty() || ident.by_ref.is_some() ||
 444                                                                                         ident.mutability.is_some() || ident.subpat.is_some() {
 445                                                                                 unimplemented!();
 446                                                                         }
 447                                                                         write!(w, ", {}{}: ", if types.skip_arg(&*arg.ty, Some(&gen_types)) { "_" } else { "" }, ident.ident).unwrap();
 448                                                                 }
 449                                                                 _ => unimplemented!(),
 450                                                         }
 451                                                         types.write_rust_type(w, Some(&gen_types), &*arg.ty);
 452                                                 }
 453                                         }
 454                                 }
 455                                 write!(w, ")").unwrap();
 456                                 match &m.sig.output {
 457                                         syn::ReturnType::Type(_, rtype) => {
 458                                                 write!(w, " -> ").unwrap();
 459                                                 types.write_rust_type(w, Some(&gen_types), &*rtype)
 460                                         },
 461                                         _ => {},
 462                                 }
 463                                 write!(w, " {{\n\t\t").unwrap();
 464                                 match export_status(&m.attrs) {
 465                                         ExportStatus::NoExport => {
 466                                                 unimplemented!();
 467                                         },
 468                                         _ => {},
 469                                 }
 470                                 if let syn::ReturnType::Type(_, rtype) = &m.sig.output {
 471                                         if let syn::Type::Reference(r) = &**rtype {
 472                                                 assert_eq!(m.sig.inputs.len(), 1); // Must only take self!
 473                                                 writeln!(w, "if let Some(f) = self.set_{} {{", m.sig.ident).unwrap();
 474                                                 writeln!(w, "\t\t\t(f)(self);").unwrap();
 475                                                 write!(w, "\t\t}}\n\t\t").unwrap();
 476                                                 types.write_from_c_conversion_to_ref_prefix(w, &*r.elem, Some(&gen_types));
 477                                                 write!(w, "self.{}", m.sig.ident).unwrap();
 478                                                 types.write_from_c_conversion_to_ref_suffix(w, &*r.elem, Some(&gen_types));
 479                                                 writeln!(w, "\n\t}}").unwrap();
 480                                                 gen_types.pop_ctx();
 481                                                 continue;
 482                                         }
 483                                 }
 484                                 write_method_var_decl_body(w, &m.sig, "\t", types, Some(&gen_types), true);
 485                                 write!(w, "(self.{})(", m.sig.ident).unwrap();
 486                                 write_method_call_params(w, &m.sig, "\t", types, Some(&gen_types), "", true);
 487
 488                                 writeln!(w, "\n\t}}").unwrap();
 489                                 gen_types.pop_ctx();
 490                         },
 491                         &syn::TraitItem::Type(ref t) => {
 492                                 if t.default.is_some() || t.generics.lt_token.is_some() { unimplemented!(); }
 493                                 let mut bounds_iter = t.bounds.iter();
 494                                 match bounds_iter.next().unwrap() {
 495                                         syn::TypeParamBound::Trait(tr) => {
 496                                                 writeln!(w, "\ttype {} = crate::{};", t.ident, types.resolve_path(&tr.path, Some(&gen_types))).unwrap();
 497                                         },
 498                                         _ => unimplemented!(),
 499                                 }
 500                                 if bounds_iter.next().is_some() { unimplemented!(); }
 501                         },
 502                         _ => unimplemented!(),
 503                 }
 504         }
 505         writeln!(w, "}}\n").unwrap();
 506         writeln!(w, "// We're essentially a pointer already, or at least a set of pointers, so allow us to be used").unwrap();
 507         writeln!(w, "// directly as a Deref trait in higher-level structs:").unwrap();
 508         writeln!(w, "impl std::ops::Deref for {} {{\n\ttype Target = Self;", trait_name).unwrap();
 509         writeln!(w, "\tfn deref(&self) -> &Self {{\n\t\tself\n\t}}\n}}").unwrap();
 510
 511         writeln!(w, "/// Calls the free function if one is set").unwrap();
 512         writeln!(w, "#[no_mangle]\npub extern \"C\" fn {}_free(this_ptr: {}) {{ }}", trait_name, trait_name).unwrap();
 513         writeln!(w, "impl Drop for {} {{", trait_name).unwrap();
 514         writeln!(w, "\tfn drop(&mut self) {{").unwrap();
 515         writeln!(w, "\t\tif let Some(f) = self.free {{").unwrap();
 516         writeln!(w, "\t\t\tf(self.this_arg);").unwrap();
 517         writeln!(w, "\t\t}}\n\t}}\n}}").unwrap();
 518
 519         write_cpp_wrapper(cpp_headers, &trait_name, true);
 520         types.trait_declared(&t.ident, t);
 521 }
 522
 523 /// Write out a simple "opaque" type (eg structs) which contain a pointer to the native Rust type
 524 /// and a flag to indicate whether Drop'ing the mapped struct drops the underlying Rust type.
 525 ///
 526 /// Also writes out a _free function and a C++ wrapper which handles calling _free.
 527 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) {
 528         // If we directly read the original type by its original name, cbindgen hits
 529         // https://github.com/eqrion/cbindgen/issues/286 Thus, instead, we import it as a temporary
 530         // name and then reference it by that name, which works around the issue.
 531         write!(w, "\nuse {}::{}::{} as native{}Import;\ntype native{} = native{}Import", types.orig_crate, types.module_path, ident, ident, ident, ident).unwrap();
 532         maybe_write_generics(w, &generics, &types, true);
 533         writeln!(w, ";\n").unwrap();
 534         writeln!(extra_headers, "struct native{}Opaque;\ntypedef struct native{}Opaque LDKnative{};", ident, ident, ident).unwrap();
 535         writeln_docs(w, &attrs, "");
 536         writeln!(w, "#[must_use]\n#[repr(C)]\npub struct {} {{\n\t/// Nearly everywhere, inner must be non-null, however in places where", struct_name).unwrap();
 537         writeln!(w, "\t/// the Rust equivalent takes an Option, it may be set to null to indicate None.").unwrap();
 538         writeln!(w, "\tpub inner: *mut native{},\n\tpub is_owned: bool,\n}}\n", ident).unwrap();
 539         writeln!(w, "impl Drop for {} {{\n\tfn drop(&mut self) {{", struct_name).unwrap();
 540         writeln!(w, "\t\tif self.is_owned && !self.inner.is_null() {{").unwrap();
 541         writeln!(w, "\t\t\tlet _ = unsafe {{ Box::from_raw(self.inner) }};\n\t\t}}\n\t}}\n}}").unwrap();
 542         writeln!(w, "#[no_mangle]\npub extern \"C\" fn {}_free(this_ptr: {}) {{ }}", struct_name, struct_name).unwrap();
 543         writeln!(w, "#[allow(unused)]").unwrap();
 544         writeln!(w, "/// Used only if an object of this type is returned as a trait impl by a method").unwrap();
 545         writeln!(w, "extern \"C\" fn {}_free_void(this_ptr: *mut c_void) {{", struct_name).unwrap();
 546         writeln!(w, "\tunsafe {{ let _ = Box::from_raw(this_ptr as *mut native{}); }}\n}}", struct_name).unwrap();
 547         writeln!(w, "#[allow(unused)]").unwrap();
 548         writeln!(w, "/// When moving out of the pointer, we have to ensure we aren't a reference, this makes that easy").unwrap();
 549         writeln!(w, "impl {} {{", struct_name).unwrap();
 550         writeln!(w, "\tpub(crate) fn take_inner(mut self) -> *mut native{} {{", struct_name).unwrap();
 551         writeln!(w, "\t\tassert!(self.is_owned);").unwrap();
 552         writeln!(w, "\t\tlet ret = self.inner;").unwrap();
 553         writeln!(w, "\t\tself.inner = std::ptr::null_mut();").unwrap();
 554         writeln!(w, "\t\tret").unwrap();
 555         writeln!(w, "\t}}\n}}").unwrap();
 556
 557         write_cpp_wrapper(cpp_headers, &format!("{}", ident), true);
 558 }
 559
 560 fn declare_struct<'a, 'b>(s: &'a syn::ItemStruct, types: &mut TypeResolver<'b, 'a>) -> bool {
 561         let export = export_status(&s.attrs);
 562         match export {
 563                 ExportStatus::Export => {},
 564                 ExportStatus::TestOnly => return false,
 565                 ExportStatus::NoExport => {
 566                         types.struct_ignored(&s.ident);
 567                         return false;
 568                 }
 569         }
 570
 571         types.struct_imported(&s.ident);
 572         true
 573 }
 574
 575 /// Writes out all the relevant mappings for a Rust struct, deferring to writeln_opaque to generate
 576 /// the struct itself, and then writing getters and setters for public, understood-type fields and
 577 /// a constructor if every field is public.
 578 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) {
 579         if !declare_struct(s, types) { return; }
 580
 581         let struct_name = &format!("{}", s.ident);
 582         writeln_opaque(w, &s.ident, struct_name, &s.generics, &s.attrs, types, extra_headers, cpp_headers);
 583
 584         if let syn::Fields::Named(fields) = &s.fields {
 585                 let mut gen_types = GenericTypes::new();
 586                 assert!(gen_types.learn_generics(&s.generics, types));
 587
 588                 let mut all_fields_settable = true;
 589                 for field in fields.named.iter() {
 590                         if let syn::Visibility::Public(_) = field.vis {
 591                                 let export = export_status(&field.attrs);
 592                                 match export {
 593                                         ExportStatus::Export => {},
 594                                         ExportStatus::NoExport|ExportStatus::TestOnly => {
 595                                                 all_fields_settable = false;
 596                                                 continue
 597                                         },
 598                                 }
 599
 600                                 if let Some(ident) = &field.ident {
 601                                         let ref_type = syn::Type::Reference(syn::TypeReference {
 602                                                 and_token: syn::Token!(&)(Span::call_site()), lifetime: None, mutability: None,
 603                                                 elem: Box::new(field.ty.clone()) });
 604                                         if types.understood_c_type(&ref_type, Some(&gen_types)) {
 605                                                 writeln_docs(w, &field.attrs, "");
 606                                                 write!(w, "#[no_mangle]\npub extern \"C\" fn {}_get_{}(this_ptr: &{}) -> ", struct_name, ident, struct_name).unwrap();
 607                                                 types.write_c_type(w, &ref_type, Some(&gen_types), true);
 608                                                 write!(w, " {{\n\tlet mut inner_val = &mut unsafe {{ &mut *this_ptr.inner }}.{};\n\t", ident).unwrap();
 609                                                 let local_var = types.write_to_c_conversion_new_var(w, &syn::Ident::new("inner_val", Span::call_site()), &ref_type, Some(&gen_types), true);
 610                                                 if local_var { write!(w, "\n\t").unwrap(); }
 611                                                 types.write_to_c_conversion_inline_prefix(w, &ref_type, Some(&gen_types), true);
 612                                                 if local_var {
 613                                                         write!(w, "inner_val").unwrap();
 614                                                 } else {
 615                                                         write!(w, "(*inner_val)").unwrap();
 616                                                 }
 617                                                 types.write_to_c_conversion_inline_suffix(w, &ref_type, Some(&gen_types), true);
 618                                                 writeln!(w, "\n}}").unwrap();
 619                                         }
 620
 621                                         if types.understood_c_type(&field.ty, Some(&gen_types)) {
 622                                                 writeln_docs(w, &field.attrs, "");
 623                                                 write!(w, "#[no_mangle]\npub extern \"C\" fn {}_set_{}(this_ptr: &mut {}, mut val: ", struct_name, ident, struct_name).unwrap();
 624                                                 types.write_c_type(w, &field.ty, Some(&gen_types), false);
 625                                                 write!(w, ") {{\n\t").unwrap();
 626                                                 let local_var = types.write_from_c_conversion_new_var(w, &syn::Ident::new("val", Span::call_site()), &field.ty, Some(&gen_types));
 627                                                 if local_var { write!(w, "\n\t").unwrap(); }
 628                                                 write!(w, "unsafe {{ &mut *this_ptr.inner }}.{} = ", ident).unwrap();
 629                                                 types.write_from_c_conversion_prefix(w, &field.ty, Some(&gen_types));
 630                                                 write!(w, "val").unwrap();
 631                                                 types.write_from_c_conversion_suffix(w, &field.ty, Some(&gen_types));
 632                                                 writeln!(w, ";\n}}").unwrap();
 633                                         } else { all_fields_settable = false; }
 634                                 } else { all_fields_settable = false; }
 635                         } else { all_fields_settable = false; }
 636                 }
 637
 638                 if all_fields_settable {
 639                         // Build a constructor!
 640                         write!(w, "#[must_use]\n#[no_mangle]\npub extern \"C\" fn {}_new(", struct_name).unwrap();
 641                         for (idx, field) in fields.named.iter().enumerate() {
 642                                 if idx != 0 { write!(w, ", ").unwrap(); }
 643                                 write!(w, "mut {}_arg: ", field.ident.as_ref().unwrap()).unwrap();
 644                                 types.write_c_type(w, &field.ty, Some(&gen_types), false);
 645                         }
 646                         write!(w, ") -> {} {{\n\t", struct_name).unwrap();
 647                         for field in fields.named.iter() {
 648                                 let field_name = format!("{}_arg", field.ident.as_ref().unwrap());
 649                                 if types.write_from_c_conversion_new_var(w, &syn::Ident::new(&field_name, Span::call_site()), &field.ty, Some(&gen_types)) {
 650                                         write!(w, "\n\t").unwrap();
 651                                 }
 652                         }
 653                         writeln!(w, "{} {{ inner: Box::into_raw(Box::new(native{} {{", struct_name, s.ident).unwrap();
 654                         for field in fields.named.iter() {
 655                                 write!(w, "\t\t{}: ", field.ident.as_ref().unwrap()).unwrap();
 656                                 types.write_from_c_conversion_prefix(w, &field.ty, Some(&gen_types));
 657                                 write!(w, "{}_arg", field.ident.as_ref().unwrap()).unwrap();
 658                                 types.write_from_c_conversion_suffix(w, &field.ty, Some(&gen_types));
 659                                 writeln!(w, ",").unwrap();
 660                         }
 661                         writeln!(w, "\t}})), is_owned: true }}\n}}").unwrap();
 662                 }
 663         }
 664 }
 665
 666 /// Prints a relevant conversion for impl *
 667 ///
 668 /// For simple impl Struct {}s, this just outputs the wrapper functions as Struct_fn_name() { .. }.
 669 ///
 670 /// For impl Trait for Struct{}s, this non-exported generates wrapper functions as
 671 /// Trait_Struct_fn_name and a Struct_as_Trait(&struct) -> Trait function which returns a populated
 672 /// Trait struct containing a pointer to the passed struct's inner field and the wrapper functions.
 673 ///
 674 /// A few non-crate Traits are hard-coded including Default.
 675 fn writeln_impl<W: std::io::Write>(w: &mut W, i: &syn::ItemImpl, types: &mut TypeResolver) {
 676         match export_status(&i.attrs) {
 677                 ExportStatus::Export => {},
 678                 ExportStatus::NoExport|ExportStatus::TestOnly => return,
 679         }
 680
 681         if let syn::Type::Tuple(_) = &*i.self_ty {
 682                 if types.understood_c_type(&*i.self_ty, None) {
 683                         let mut gen_types = GenericTypes::new();
 684                         if !gen_types.learn_generics(&i.generics, types) {
 685                                 eprintln!("Not implementing anything for `impl (..)` due to not understood generics");
 686                                 return;
 687                         }
 688
 689                         if i.defaultness.is_some() || i.unsafety.is_some() { unimplemented!(); }
 690                         if let Some(trait_path) = i.trait_.as_ref() {
 691                                 if trait_path.0.is_some() { unimplemented!(); }
 692                                 if types.understood_c_path(&trait_path.1) {
 693                                         eprintln!("Not implementing anything for `impl Trait for (..)` - we only support manual defines");
 694                                         return;
 695                                 } else {
 696                                         // Just do a manual implementation:
 697                                         maybe_convert_trait_impl(w, &trait_path.1, &*i.self_ty, types, &gen_types);
 698                                 }
 699                         } else {
 700                                 eprintln!("Not implementing anything for plain `impl (..)` block - we only support `impl Trait for (..)` blocks");
 701                                 return;
 702                         }
 703                 }
 704                 return;
 705         }
 706         if let &syn::Type::Path(ref p) = &*i.self_ty {
 707                 if p.qself.is_some() { unimplemented!(); }
 708                 if let Some(ident) = single_ident_generic_path_to_ident(&p.path) {
 709                         if let Some(resolved_path) = types.maybe_resolve_non_ignored_ident(&ident) {
 710                                 let mut gen_types = GenericTypes::new();
 711                                 if !gen_types.learn_generics(&i.generics, types) {
 712                                         eprintln!("Not implementing anything for impl {} due to not understood generics", ident);
 713                                         return;
 714                                 }
 715
 716                                 if i.defaultness.is_some() || i.unsafety.is_some() { unimplemented!(); }
 717                                 if let Some(trait_path) = i.trait_.as_ref() {
 718                                         if trait_path.0.is_some() { unimplemented!(); }
 719                                         if types.understood_c_path(&trait_path.1) {
 720                                                 let full_trait_path = types.resolve_path(&trait_path.1, None);
 721                                                 let trait_obj = *types.crate_types.traits.get(&full_trait_path).unwrap();
 722                                                 // We learn the associated types maping from the original trait object.
 723                                                 // That's great, except that they are unresolved idents, so if we learn
 724                                                 // mappings from a trai defined in a different file, we may mis-resolve or
 725                                                 // fail to resolve the mapped types.
 726                                                 gen_types.learn_associated_types(trait_obj, types);
 727                                                 let mut impl_associated_types = HashMap::new();
 728                                                 for item in i.items.iter() {
 729                                                         match item {
 730                                                                 syn::ImplItem::Type(t) => {
 731                                                                         if let syn::Type::Path(p) = &t.ty {
 732                                                                                 if let Some(id) = single_ident_generic_path_to_ident(&p.path) {
 733                                                                                         impl_associated_types.insert(&t.ident, id);
 734                                                                                 }
 735                                                                         }
 736                                                                 },
 737                                                                 _ => {},
 738                                                         }
 739                                                 }
 740
 741                                                 let export = export_status(&trait_obj.attrs);
 742                                                 match export {
 743                                                         ExportStatus::Export => {},
 744                                                         ExportStatus::NoExport|ExportStatus::TestOnly => return,
 745                                                 }
 746
 747                                                 // For cases where we have a concrete native object which implements a
 748                                                 // trait and need to return the C-mapped version of the trait, provide a
 749                                                 // From<> implementation which does all the work to ensure free is handled
 750                                                 // properly. This way we can call this method from deep in the
 751                                                 // type-conversion logic without actually knowing the concrete native type.
 752                                                 writeln!(w, "impl From<native{}> for crate::{} {{", ident, full_trait_path).unwrap();
 753                                                 writeln!(w, "\tfn from(obj: native{}) -> Self {{", ident).unwrap();
 754                                                 writeln!(w, "\t\tlet mut rust_obj = {} {{ inner: Box::into_raw(Box::new(obj)), is_owned: true }};", ident).unwrap();
 755                                                 writeln!(w, "\t\tlet mut ret = {}_as_{}(&rust_obj);", ident, trait_obj.ident).unwrap();
 756                                                 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();
 757                                                 writeln!(w, "\t\trust_obj.inner = std::ptr::null_mut();").unwrap();
 758                                                 writeln!(w, "\t\tret.free = Some({}_free_void);", ident).unwrap();
 759                                                 writeln!(w, "\t\tret\n\t}}\n}}").unwrap();
 760
 761                                                 write!(w, "#[no_mangle]\npub extern \"C\" fn {}_as_{}(this_arg: &{}) -> crate::{} {{\n", ident, trait_obj.ident, ident, full_trait_path).unwrap();
 762                                                 writeln!(w, "\tcrate::{} {{", full_trait_path).unwrap();
 763                                                 writeln!(w, "\t\tthis_arg: unsafe {{ (*this_arg).inner as *mut c_void }},").unwrap();
 764                                                 writeln!(w, "\t\tfree: None,").unwrap();
 765
 766                                                 macro_rules! write_meth {
 767                                                         ($m: expr, $trait: expr, $indent: expr) => {
 768                                                                 let trait_method = $trait.items.iter().filter_map(|item| {
 769                                                                         if let syn::TraitItem::Method(t_m) = item { Some(t_m) } else { None }
 770                                                                 }).find(|trait_meth| trait_meth.sig.ident == $m.sig.ident).unwrap();
 771                                                                 match export_status(&trait_method.attrs) {
 772                                                                         ExportStatus::Export => {},
 773                                                                         ExportStatus::NoExport => {
 774                                                                                 write!(w, "{}\t\t//XXX: Need to export {}\n", $indent, $m.sig.ident).unwrap();
 775                                                                                 continue;
 776                                                                         },
 777                                                                         ExportStatus::TestOnly => continue,
 778                                                                 }
 779
 780                                                                 let mut printed = false;
 781                                                                 if let syn::ReturnType::Type(_, rtype) = &$m.sig.output {
 782                                                                         if let syn::Type::Reference(r) = &**rtype {
 783                                                                                 write!(w, "\n\t\t{}{}: ", $indent, $m.sig.ident).unwrap();
 784                                                                                 types.write_empty_rust_val(Some(&gen_types), w, &*r.elem);
 785                                                                                 writeln!(w, ",\n{}\t\tset_{}: Some({}_{}_set_{}),", $indent, $m.sig.ident, ident, trait_obj.ident, $m.sig.ident).unwrap();
 786                                                                                 printed = true;
 787                                                                         }
 788                                                                 }
 789                                                                 if !printed {
 790                                                                         write!(w, "{}\t\t{}: {}_{}_{},\n", $indent, $m.sig.ident, ident, trait_obj.ident, $m.sig.ident).unwrap();
 791                                                                 }
 792                                                         }
 793                                                 }
 794                                                 for item in trait_obj.items.iter() {
 795                                                         match item {
 796                                                                 syn::TraitItem::Method(m) => {
 797                                                                         write_meth!(m, trait_obj, "");
 798                                                                 },
 799                                                                 _ => {},
 800                                                         }
 801                                                 }
 802                                                 walk_supertraits!(trait_obj, Some(&types), (
 803                                                         ("Clone", _) => {
 804                                                                 writeln!(w, "\t\tclone: Some({}_clone_void),", ident).unwrap();
 805                                                         },
 806                                                         ("Sync", _) => {}, ("Send", _) => {},
 807                                                         ("std::marker::Sync", _) => {}, ("std::marker::Send", _) => {},
 808                                                         (s, t) => {
 809                                                                 if let Some(supertrait_obj) = types.crate_types.traits.get(s) {
 810                                                                         writeln!(w, "\t\t{}: crate::{} {{", t, s).unwrap();
 811                                                                         writeln!(w, "\t\t\tthis_arg: unsafe {{ (*this_arg).inner as *mut c_void }},").unwrap();
 812                                                                         writeln!(w, "\t\t\tfree: None,").unwrap();
 813                                                                         for item in supertrait_obj.items.iter() {
 814                                                                                 match item {
 815                                                                                         syn::TraitItem::Method(m) => {
 816                                                                                                 write_meth!(m, supertrait_obj, "\t");
 817                                                                                         },
 818                                                                                         _ => {},
 819                                                                                 }
 820                                                                         }
 821                                                                         write!(w, "\t\t}},\n").unwrap();
 822                                                                 } else {
 823                                                                         write_trait_impl_field_assign(w, s, ident);
 824                                                                 }
 825                                                         }
 826                                                 ) );
 827                                                 write!(w, "\t}}\n}}\nuse {}::{} as {}TraitImport;\n", types.orig_crate, full_trait_path, trait_obj.ident).unwrap();
 828
 829                                                 macro_rules! impl_meth {
 830                                                         ($m: expr, $trait: expr, $indent: expr) => {
 831                                                                 let trait_method = $trait.items.iter().filter_map(|item| {
 832                                                                         if let syn::TraitItem::Method(t_m) = item { Some(t_m) } else { None }
 833                                                                 }).find(|trait_meth| trait_meth.sig.ident == $m.sig.ident).unwrap();
 834                                                                 match export_status(&trait_method.attrs) {
 835                                                                         ExportStatus::Export => {},
 836                                                                         ExportStatus::NoExport|ExportStatus::TestOnly => continue,
 837                                                                 }
 838
 839                                                                 if let syn::ReturnType::Type(_, _) = &$m.sig.output {
 840                                                                         writeln!(w, "#[must_use]").unwrap();
 841                                                                 }
 842                                                                 write!(w, "extern \"C\" fn {}_{}_{}(", ident, trait_obj.ident, $m.sig.ident).unwrap();
 843                                                                 gen_types.push_ctx();
 844                                                                 assert!(gen_types.learn_generics(&$m.sig.generics, types));
 845                                                                 write_method_params(w, &$m.sig, "c_void", types, Some(&gen_types), true, true);
 846                                                                 write!(w, " {{\n\t").unwrap();
 847                                                                 write_method_var_decl_body(w, &$m.sig, "", types, Some(&gen_types), false);
 848                                                                 let mut takes_self = false;
 849                                                                 for inp in $m.sig.inputs.iter() {
 850                                                                         if let syn::FnArg::Receiver(_) = inp {
 851                                                                                 takes_self = true;
 852                                                                         }
 853                                                                 }
 854                                                                 if takes_self {
 855                                                                         write!(w, "unsafe {{ &mut *(this_arg as *mut native{}) }}.{}(", ident, $m.sig.ident).unwrap();
 856                                                                 } else {
 857                                                                         write!(w, "{}::{}::{}(", types.orig_crate, resolved_path, $m.sig.ident).unwrap();
 858                                                                 }
 859
 860                                                                 let mut real_type = "".to_string();
 861                                                                 match &$m.sig.output {
 862                                                                         syn::ReturnType::Type(_, rtype) => {
 863                                                                                 if let Some(mut remaining_path) = first_seg_self(&*rtype) {
 864                                                                                         if let Some(associated_seg) = get_single_remaining_path_seg(&mut remaining_path) {
 865                                                                                                 real_type = format!("{}", impl_associated_types.get(associated_seg).unwrap());
 866                                                                                         }
 867                                                                                 }
 868                                                                         },
 869                                                                         _ => {},
 870                                                                 }
 871                                                                 write_method_call_params(w, &$m.sig, "", types, Some(&gen_types), &real_type, false);
 872                                                                 gen_types.pop_ctx();
 873                                                                 write!(w, "\n}}\n").unwrap();
 874                                                                 if let syn::ReturnType::Type(_, rtype) = &$m.sig.output {
 875                                                                         if let syn::Type::Reference(r) = &**rtype {
 876                                                                                 assert_eq!($m.sig.inputs.len(), 1); // Must only take self
 877                                                                                 writeln!(w, "extern \"C\" fn {}_{}_set_{}(trait_self_arg: &{}) {{", ident, trait_obj.ident, $m.sig.ident, trait_obj.ident).unwrap();
 878                                                                                 writeln!(w, "\t// This is a bit race-y in the general case, but for our specific use-cases today, we're safe").unwrap();
 879                                                                                 writeln!(w, "\t// Specifically, we must ensure that the first time we're called it can never be in parallel").unwrap();
 880                                                                                 write!(w, "\tif ").unwrap();
 881                                                                                 types.write_empty_rust_val_check(Some(&gen_types), w, &*r.elem, &format!("trait_self_arg.{}", $m.sig.ident));
 882                                                                                 writeln!(w, " {{").unwrap();
 883                                                                                 writeln!(w, "\t\tunsafe {{ &mut *(trait_self_arg as *const {}  as *mut {}) }}.{} = {}_{}_{}(trait_self_arg.this_arg);", trait_obj.ident, trait_obj.ident, $m.sig.ident, ident, trait_obj.ident, $m.sig.ident).unwrap();
 884                                                                                 writeln!(w, "\t}}").unwrap();
 885                                                                                 writeln!(w, "}}").unwrap();
 886                                                                         }
 887                                                                 }
 888                                                         }
 889                                                 }
 890
 891                                                 for item in i.items.iter() {
 892                                                         match item {
 893                                                                 syn::ImplItem::Method(m) => {
 894                                                                         impl_meth!(m, trait_obj, "");
 895                                                                 },
 896                                                                 syn::ImplItem::Type(_) => {},
 897                                                                 _ => unimplemented!(),
 898                                                         }
 899                                                 }
 900                                                 walk_supertraits!(trait_obj, Some(&types), (
 901                                                         (s, t) => {
 902                                                                 if let Some(supertrait_obj) = types.crate_types.traits.get(s).cloned() {
 903                                                                         writeln!(w, "use {}::{} as native{}Trait;", types.orig_crate, s, t).unwrap();
 904                                                                         for item in supertrait_obj.items.iter() {
 905                                                                                 match item {
 906                                                                                         syn::TraitItem::Method(m) => {
 907                                                                                                 impl_meth!(m, supertrait_obj, "\t");
 908                                                                                         },
 909                                                                                         _ => {},
 910                                                                                 }
 911                                                                         }
 912                                                                 }
 913                                                         }
 914                                                 ) );
 915                                                 write!(w, "\n").unwrap();
 916                                         } else if path_matches_nongeneric(&trait_path.1, &["From"]) {
 917                                         } else if path_matches_nongeneric(&trait_path.1, &["Default"]) {
 918                                                 write!(w, "#[must_use]\n#[no_mangle]\npub extern \"C\" fn {}_default() -> {} {{\n", ident, ident).unwrap();
 919                                                 write!(w, "\t{} {{ inner: Box::into_raw(Box::new(Default::default())), is_owned: true }}\n", ident).unwrap();
 920                                                 write!(w, "}}\n").unwrap();
 921                                         } else if path_matches_nongeneric(&trait_path.1, &["core", "cmp", "PartialEq"]) {
 922                                         } else if path_matches_nongeneric(&trait_path.1, &["core", "clone", "Clone"]) && types.c_type_has_inner_from_path(&resolved_path) {
 923                                                 writeln!(w, "impl Clone for {} {{", ident).unwrap();
 924                                                 writeln!(w, "\tfn clone(&self) -> Self {{").unwrap();
 925                                                 writeln!(w, "\t\tSelf {{").unwrap();
 926                                                 writeln!(w, "\t\t\tinner: if self.inner.is_null() {{ std::ptr::null_mut() }} else {{").unwrap();
 927                                                 writeln!(w, "\t\t\t\tBox::into_raw(Box::new(unsafe {{ &*self.inner }}.clone())) }},").unwrap();
 928                                                 writeln!(w, "\t\t\tis_owned: true,").unwrap();
 929                                                 writeln!(w, "\t\t}}\n\t}}\n}}").unwrap();
 930                                                 writeln!(w, "#[allow(unused)]").unwrap();
 931                                                 writeln!(w, "/// Used only if an object of this type is returned as a trait impl by a method").unwrap();
 932                                                 writeln!(w, "pub(crate) extern \"C\" fn {}_clone_void(this_ptr: *const c_void) -> *mut c_void {{", ident).unwrap();
 933                                                 writeln!(w, "\tBox::into_raw(Box::new(unsafe {{ (*(this_ptr as *mut native{})).clone() }})) as *mut c_void", ident).unwrap();
 934                                                 writeln!(w, "}}").unwrap();
 935                                                 writeln!(w, "#[no_mangle]").unwrap();
 936                                                 writeln!(w, "pub extern \"C\" fn {}_clone(orig: &{}) -> {} {{", ident, ident, ident).unwrap();
 937                                                 writeln!(w, "\torig.clone()").unwrap();
 938                                                 writeln!(w, "}}").unwrap();
 939                                         } else {
 940                                                 //XXX: implement for other things like ToString
 941                                                 // If we have no generics, try a manual implementation:
 942                                                 maybe_convert_trait_impl(w, &trait_path.1, &*i.self_ty, types, &gen_types);
 943                                         }
 944                                 } else {
 945                                         let declared_type = (*types.get_declared_type(&ident).unwrap()).clone();
 946                                         for item in i.items.iter() {
 947                                                 match item {
 948                                                         syn::ImplItem::Method(m) => {
 949                                                                 if let syn::Visibility::Public(_) = m.vis {
 950                                                                         match export_status(&m.attrs) {
 951                                                                                 ExportStatus::Export => {},
 952                                                                                 ExportStatus::NoExport|ExportStatus::TestOnly => continue,
 953                                                                         }
 954                                                                         if m.defaultness.is_some() { unimplemented!(); }
 955                                                                         writeln_docs(w, &m.attrs, "");
 956                                                                         if let syn::ReturnType::Type(_, _) = &m.sig.output {
 957                                                                                 writeln!(w, "#[must_use]").unwrap();
 958                                                                         }
 959                                                                         write!(w, "#[no_mangle]\npub extern \"C\" fn {}_{}(", ident, m.sig.ident).unwrap();
 960                                                                         let ret_type = match &declared_type {
 961                                                                                 DeclType::MirroredEnum => format!("{}", ident),
 962                                                                                 DeclType::StructImported => format!("{}", ident),
 963                                                                                 _ => unimplemented!(),
 964                                                                         };
 965                                                                         gen_types.push_ctx();
 966                                                                         assert!(gen_types.learn_generics(&m.sig.generics, types));
 967                                                                         write_method_params(w, &m.sig, &ret_type, types, Some(&gen_types), false, true);
 968                                                                         write!(w, " {{\n\t").unwrap();
 969                                                                         write_method_var_decl_body(w, &m.sig, "", types, Some(&gen_types), false);
 970                                                                         let mut takes_self = false;
 971                                                                         let mut takes_mut_self = false;
 972                                                                         for inp in m.sig.inputs.iter() {
 973                                                                                 if let syn::FnArg::Receiver(r) = inp {
 974                                                                                         takes_self = true;
 975                                                                                         if r.mutability.is_some() { takes_mut_self = true; }
 976                                                                                 }
 977                                                                         }
 978                                                                         if takes_mut_self {
 979                                                                                 write!(w, "unsafe {{ &mut (*(this_arg.inner as *mut native{})) }}.{}(", ident, m.sig.ident).unwrap();
 980                                                                         } else if takes_self {
 981                                                                                 write!(w, "unsafe {{ &*this_arg.inner }}.{}(", m.sig.ident).unwrap();
 982                                                                         } else {
 983                                                                                 write!(w, "{}::{}::{}(", types.orig_crate, resolved_path, m.sig.ident).unwrap();
 984                                                                         }
 985                                                                         write_method_call_params(w, &m.sig, "", types, Some(&gen_types), &ret_type, false);
 986                                                                         gen_types.pop_ctx();
 987                                                                         writeln!(w, "\n}}\n").unwrap();
 988                                                                 }
 989                                                         },
 990                                                         _ => {},
 991                                                 }
 992                                         }
 993                                 }
 994                         } else {
 995                                 eprintln!("Not implementing anything for {} due to no-resolve (probably the type isn't pub or its marked not exported)", ident);
 996                         }
 997                 }
 998         }
 999 }
1000
1001 /// Returns true if the enum will be mapped as an opaue (ie struct with a pointer to the underlying
1002 /// type), otherwise it is mapped into a transparent, C-compatible version of itself.
1003 fn is_enum_opaque(e: &syn::ItemEnum) -> bool {
1004         for var in e.variants.iter() {
1005                 if let syn::Fields::Unit = var.fields {
1006                 } else if let syn::Fields::Named(fields) = &var.fields {
1007                         for field in fields.named.iter() {
1008                                 match export_status(&field.attrs) {
1009                                         ExportStatus::Export|ExportStatus::TestOnly => {},
1010                                         ExportStatus::NoExport => return true,
1011                                 }
1012                         }
1013                 } else {
1014                         return true;
1015                 }
1016         }
1017         false
1018 }
1019
1020 fn declare_enum<'a, 'b>(e: &'a syn::ItemEnum, types: &mut TypeResolver<'b, 'a>) {
1021         match export_status(&e.attrs) {
1022                 ExportStatus::Export => {},
1023                 ExportStatus::NoExport|ExportStatus::TestOnly => return,
1024         }
1025
1026         if is_enum_opaque(e) {
1027                 types.enum_ignored(&e.ident);
1028         } else {
1029                 types.mirrored_enum_declared(&e.ident);
1030         }
1031 }
1032
1033 /// Print a mapping of an enum. If all of the enum's fields are C-mapped in some form (or the enum
1034 /// is unitary), we generate an equivalent enum with all types replaced with their C mapped
1035 /// versions followed by conversion functions which map between the Rust version and the C mapped
1036 /// version.
1037 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) {
1038         match export_status(&e.attrs) {
1039                 ExportStatus::Export => {},
1040                 ExportStatus::NoExport|ExportStatus::TestOnly => return,
1041         }
1042
1043         if is_enum_opaque(e) {
1044                 eprintln!("Skipping enum {} as it contains non-unit fields", e.ident);
1045                 writeln_opaque(w, &e.ident, &format!("{}", e.ident), &e.generics, &e.attrs, types, extra_headers, cpp_headers);
1046                 return;
1047         }
1048         writeln_docs(w, &e.attrs, "");
1049
1050         if e.generics.lt_token.is_some() {
1051                 unimplemented!();
1052         }
1053
1054         let mut needs_free = false;
1055
1056         writeln!(w, "#[must_use]\n#[derive(Clone)]\n#[repr(C)]\npub enum {} {{", e.ident).unwrap();
1057         for var in e.variants.iter() {
1058                 assert_eq!(export_status(&var.attrs), ExportStatus::Export); // We can't partially-export a mirrored enum
1059                 writeln_docs(w, &var.attrs, "\t");
1060                 write!(w, "\t{}", var.ident).unwrap();
1061                 if let syn::Fields::Named(fields) = &var.fields {
1062                         needs_free = true;
1063                         writeln!(w, " {{").unwrap();
1064                         for field in fields.named.iter() {
1065                                 if export_status(&field.attrs) == ExportStatus::TestOnly { continue; }
1066                                 write!(w, "\t\t{}: ", field.ident.as_ref().unwrap()).unwrap();
1067                                 types.write_c_type(w, &field.ty, None, false);
1068                                 writeln!(w, ",").unwrap();
1069                         }
1070                         write!(w, "\t}}").unwrap();
1071                 }
1072                 if var.discriminant.is_some() { unimplemented!(); }
1073                 writeln!(w, ",").unwrap();
1074         }
1075         writeln!(w, "}}\nuse {}::{}::{} as native{};\nimpl {} {{", types.orig_crate, types.module_path, e.ident, e.ident, e.ident).unwrap();
1076
1077         macro_rules! write_conv {
1078                 ($fn_sig: expr, $to_c: expr, $ref: expr) => {
1079                         writeln!(w, "\t#[allow(unused)]\n\tpub(crate) fn {} {{\n\t\tmatch {} {{", $fn_sig, if $to_c { "native" } else { "self" }).unwrap();
1080                         for var in e.variants.iter() {
1081                                 write!(w, "\t\t\t{}{}::{} ", if $to_c { "native" } else { "" }, e.ident, var.ident).unwrap();
1082                                 if let syn::Fields::Named(fields) = &var.fields {
1083                                         write!(w, "{{").unwrap();
1084                                         for field in fields.named.iter() {
1085                                                 if export_status(&field.attrs) == ExportStatus::TestOnly { continue; }
1086                                                 write!(w, "{}{}, ", if $ref { "ref " } else { "mut " }, field.ident.as_ref().unwrap()).unwrap();
1087                                         }
1088                                         write!(w, "}} ").unwrap();
1089                                 }
1090                                 write!(w, "=>").unwrap();
1091                                 if let syn::Fields::Named(fields) = &var.fields {
1092                                         write!(w, " {{\n\t\t\t\t").unwrap();
1093                                         for field in fields.named.iter() {
1094                                                 if export_status(&field.attrs) == ExportStatus::TestOnly { continue; }
1095                                                 let mut sink = ::std::io::sink();
1096                                                 let mut out: &mut dyn std::io::Write = if $ref { &mut sink } else { w };
1097                                                 let new_var = if $to_c {
1098                                                         types.write_to_c_conversion_new_var(&mut out, field.ident.as_ref().unwrap(), &field.ty, None, false)
1099                                                 } else {
1100                                                         types.write_from_c_conversion_new_var(&mut out, field.ident.as_ref().unwrap(), &field.ty, None)
1101                                                 };
1102                                                 if $ref || new_var {
1103                                                         if $ref {
1104                                                                 write!(w, "let mut {}_nonref = (*{}).clone();\n\t\t\t\t", field.ident.as_ref().unwrap(), field.ident.as_ref().unwrap()).unwrap();
1105                                                                 if new_var {
1106                                                                         let nonref_ident = syn::Ident::new(&format!("{}_nonref", field.ident.as_ref().unwrap()), Span::call_site());
1107                                                                         if $to_c {
1108                                                                                 types.write_to_c_conversion_new_var(w, &nonref_ident, &field.ty, None, false);
1109                                                                         } else {
1110                                                                                 types.write_from_c_conversion_new_var(w, &nonref_ident, &field.ty, None);
1111                                                                         }
1112                                                                         write!(w, "\n\t\t\t\t").unwrap();
1113                                                                 }
1114                                                         } else {
1115                                                                 write!(w, "\n\t\t\t\t").unwrap();
1116                                                         }
1117                                                 }
1118                                         }
1119                                 } else { write!(w, " ").unwrap(); }
1120                                 write!(w, "{}{}::{}", if $to_c { "" } else { "native" }, e.ident, var.ident).unwrap();
1121                                 if let syn::Fields::Named(fields) = &var.fields {
1122                                         write!(w, " {{").unwrap();
1123                                         for field in fields.named.iter() {
1124                                                 if export_status(&field.attrs) == ExportStatus::TestOnly { continue; }
1125                                                 write!(w, "\n\t\t\t\t\t{}: ", field.ident.as_ref().unwrap()).unwrap();
1126                                                 if $to_c {
1127                                                         types.write_to_c_conversion_inline_prefix(w, &field.ty, None, false);
1128                                                 } else {
1129                                                         types.write_from_c_conversion_prefix(w, &field.ty, None);
1130                                                 }
1131                                                 write!(w, "{}{}",
1132                                                         field.ident.as_ref().unwrap(),
1133                                                         if $ref { "_nonref" } else { "" }).unwrap();
1134                                                 if $to_c {
1135                                                         types.write_to_c_conversion_inline_suffix(w, &field.ty, None, false);
1136                                                 } else {
1137                                                         types.write_from_c_conversion_suffix(w, &field.ty, None);
1138                                                 }
1139                                                 write!(w, ",").unwrap();
1140                                         }
1141                                         writeln!(w, "\n\t\t\t\t}}").unwrap();
1142                                         write!(w, "\t\t\t}}").unwrap();
1143                                 }
1144                                 writeln!(w, ",").unwrap();
1145                         }
1146                         writeln!(w, "\t\t}}\n\t}}").unwrap();
1147                 }
1148         }
1149
1150         write_conv!(format!("to_native(&self) -> native{}", e.ident), false, true);
1151         write_conv!(format!("into_native(self) -> native{}", e.ident), false, false);
1152         write_conv!(format!("from_native(native: &native{}) -> Self", e.ident), true, true);
1153         write_conv!(format!("native_into(native: native{}) -> Self", e.ident), true, false);
1154         writeln!(w, "}}").unwrap();
1155
1156         if needs_free {
1157                 writeln!(w, "#[no_mangle]\npub extern \"C\" fn {}_free(this_ptr: {}) {{ }}", e.ident, e.ident).unwrap();
1158         }
1159         writeln!(w, "#[no_mangle]").unwrap();
1160         writeln!(w, "pub extern \"C\" fn {}_clone(orig: &{}) -> {} {{", e.ident, e.ident, e.ident).unwrap();
1161         writeln!(w, "\torig.clone()").unwrap();
1162         writeln!(w, "}}").unwrap();
1163         write_cpp_wrapper(cpp_headers, &format!("{}", e.ident), needs_free);
1164 }
1165
1166 fn writeln_fn<'a, 'b, W: std::io::Write>(w: &mut W, f: &'a syn::ItemFn, types: &mut TypeResolver<'b, 'a>) {
1167         match export_status(&f.attrs) {
1168                 ExportStatus::Export => {},
1169                 ExportStatus::NoExport|ExportStatus::TestOnly => return,
1170         }
1171         writeln_docs(w, &f.attrs, "");
1172
1173         let mut gen_types = GenericTypes::new();
1174         if !gen_types.learn_generics(&f.sig.generics, types) { return; }
1175
1176         write!(w, "#[no_mangle]\npub extern \"C\" fn {}(", f.sig.ident).unwrap();
1177         write_method_params(w, &f.sig, "", types, Some(&gen_types), false, true);
1178         write!(w, " {{\n\t").unwrap();
1179         write_method_var_decl_body(w, &f.sig, "", types, Some(&gen_types), false);
1180         write!(w, "{}::{}::{}(", types.orig_crate, types.module_path, f.sig.ident).unwrap();
1181         write_method_call_params(w, &f.sig, "", types, Some(&gen_types), "", false);
1182         writeln!(w, "\n}}\n").unwrap();
1183 }
1184
1185 // ********************************
1186 // *** File/Crate Walking Logic ***
1187 // ********************************
1188 /// A public module
1189 struct ASTModule {
1190         pub attrs: Vec<syn::Attribute>,
1191         pub items: Vec<syn::Item>,
1192         pub submods: Vec<String>,
1193 }
1194 /// A struct containing the syn::File AST for each file in the crate.
1195 struct FullLibraryAST {
1196         modules: HashMap<String, ASTModule, NonRandomHash>,
1197 }
1198 impl FullLibraryAST {
1199         fn load_module(&mut self, module: String, attrs: Vec<syn::Attribute>, mut items: Vec<syn::Item>) {
1200                 let mut non_mod_items = Vec::with_capacity(items.len());
1201                 let mut submods = Vec::with_capacity(items.len());
1202                 for item in items.drain(..) {
1203                         match item {
1204                                 syn::Item::Mod(m) if m.content.is_some() => {
1205                                         if export_status(&m.attrs) == ExportStatus::Export {
1206                                                 if let syn::Visibility::Public(_) = m.vis {
1207                                                         let modident = format!("{}", m.ident);
1208                                                         let modname = if module != "" {
1209                                                                 module.clone() + "::" + &modident
1210                                                         } else {
1211                                                                 modident.clone()
1212                                                         };
1213                                                         self.load_module(modname, m.attrs, m.content.unwrap().1);
1214                                                         submods.push(modident);
1215                                                 }
1216                                         }
1217                                 },
1218                                 _ => { non_mod_items.push(item); }
1219                         }
1220                 }
1221                 self.modules.insert(module, ASTModule { attrs, items: non_mod_items, submods });
1222         }
1223
1224         pub fn load_lib(lib: syn::File) -> Self {
1225                 assert_eq!(export_status(&lib.attrs), ExportStatus::Export);
1226                 let mut res = Self { modules: HashMap::default() };
1227                 res.load_module("".to_owned(), lib.attrs, lib.items);
1228                 res
1229         }
1230 }
1231
1232 /// Do the Real Work of mapping an original file to C-callable wrappers. Creates a new file at
1233 /// `out_path` and fills it with wrapper structs/functions to allow calling the things in the AST
1234 /// at `module` from C.
1235 fn convert_file<'a, 'b>(libast: &'a FullLibraryAST, crate_types: &mut CrateTypes<'a>, out_dir: &str, orig_crate: &str, header_file: &mut File, cpp_header_file: &mut File) {
1236         for (module, astmod) in libast.modules.iter() {
1237                 let ASTModule { ref attrs, ref items, ref submods } = astmod;
1238                 assert_eq!(export_status(&attrs), ExportStatus::Export);
1239
1240                 let new_file_path = if submods.is_empty() {
1241                         format!("{}/{}.rs", out_dir, module.replace("::", "/"))
1242                 } else if module != "" {
1243                         format!("{}/{}/mod.rs", out_dir, module.replace("::", "/"))
1244                 } else {
1245                         format!("{}/lib.rs", out_dir)
1246                 };
1247                 let _ = std::fs::create_dir((&new_file_path.as_ref() as &std::path::Path).parent().unwrap());
1248                 let mut out = std::fs::OpenOptions::new().write(true).create(true).truncate(true)
1249                         .open(new_file_path).expect("Unable to open new src file");
1250
1251                 writeln_docs(&mut out, &attrs, "");
1252
1253                 if module == "" {
1254                         // Special-case the top-level lib.rs with various lint allows and a pointer to the c_types
1255                         // and bitcoin hand-written modules.
1256                         writeln!(out, "#![allow(unknown_lints)]").unwrap();
1257                         writeln!(out, "#![allow(non_camel_case_types)]").unwrap();
1258                         writeln!(out, "#![allow(non_snake_case)]").unwrap();
1259                         writeln!(out, "#![allow(unused_imports)]").unwrap();
1260                         writeln!(out, "#![allow(unused_variables)]").unwrap();
1261                         writeln!(out, "#![allow(unused_mut)]").unwrap();
1262                         writeln!(out, "#![allow(unused_parens)]").unwrap();
1263                         writeln!(out, "#![allow(unused_unsafe)]").unwrap();
1264                         writeln!(out, "#![allow(unused_braces)]").unwrap();
1265                         writeln!(out, "mod c_types;").unwrap();
1266                         writeln!(out, "mod bitcoin;").unwrap();
1267                 } else {
1268                         writeln!(out, "\nuse std::ffi::c_void;\nuse bitcoin::hashes::Hash;\nuse crate::c_types::*;\n").unwrap();
1269                 }
1270
1271                 for m in submods {
1272                         writeln!(out, "pub mod {};", m).unwrap();
1273                 }
1274
1275                 eprintln!("Converting {} entries...", module);
1276
1277                 let mut type_resolver = TypeResolver::new(orig_crate, module, crate_types);
1278
1279                 // First pass over the items and fill in imports and file-declared objects in the type resolver
1280                 for item in items.iter() {
1281                         match item {
1282                                 syn::Item::Use(u) => type_resolver.process_use(&mut out, &u),
1283                                 syn::Item::Struct(s) => {
1284                                         if let syn::Visibility::Public(_) = s.vis {
1285                                                 declare_struct(&s, &mut type_resolver);
1286                                         }
1287                                 },
1288                                 syn::Item::Enum(e) => {
1289                                         if let syn::Visibility::Public(_) = e.vis {
1290                                                 declare_enum(&e, &mut type_resolver);
1291                                         }
1292                                 },
1293                                 _ => {},
1294                         }
1295                 }
1296
1297                 for item in items.iter() {
1298                         match item {
1299                                 syn::Item::Use(_) => {}, // Handled above
1300                                 syn::Item::Static(_) => {},
1301                                 syn::Item::Enum(e) => {
1302                                         if let syn::Visibility::Public(_) = e.vis {
1303                                                 writeln_enum(&mut out, &e, &mut type_resolver, header_file, cpp_header_file);
1304                                         }
1305                                 },
1306                                 syn::Item::Impl(i) => {
1307                                         writeln_impl(&mut out, &i, &mut type_resolver);
1308                                 },
1309                                 syn::Item::Struct(s) => {
1310                                         if let syn::Visibility::Public(_) = s.vis {
1311                                                 writeln_struct(&mut out, &s, &mut type_resolver, header_file, cpp_header_file);
1312                                         }
1313                                 },
1314                                 syn::Item::Trait(t) => {
1315                                         if let syn::Visibility::Public(_) = t.vis {
1316                                                 writeln_trait(&mut out, &t, &mut type_resolver, header_file, cpp_header_file);
1317                                         }
1318                                 },
1319                                 syn::Item::Mod(_) => {}, // We don't have to do anything - the top loop handles these.
1320                                 syn::Item::Const(c) => {
1321                                         // Re-export any primitive-type constants.
1322                                         if let syn::Visibility::Public(_) = c.vis {
1323                                                 if let syn::Type::Path(p) = &*c.ty {
1324                                                         let resolved_path = type_resolver.resolve_path(&p.path, None);
1325                                                         if type_resolver.is_primitive(&resolved_path) {
1326                                                                 writeln!(out, "\n#[no_mangle]").unwrap();
1327                                                                 writeln!(out, "pub static {}: {} = {}::{}::{};", c.ident, resolved_path, orig_crate, module, c.ident).unwrap();
1328                                                         }
1329                                                 }
1330                                         }
1331                                 },
1332                                 syn::Item::Type(t) => {
1333                                         if let syn::Visibility::Public(_) = t.vis {
1334                                                 match export_status(&t.attrs) {
1335                                                         ExportStatus::Export => {},
1336                                                         ExportStatus::NoExport|ExportStatus::TestOnly => continue,
1337                                                 }
1338
1339                                                 let mut process_alias = true;
1340                                                 for tok in t.generics.params.iter() {
1341                                                         if let syn::GenericParam::Lifetime(_) = tok {}
1342                                                         else { process_alias = false; }
1343                                                 }
1344                                                 if process_alias {
1345                                                         match &*t.ty {
1346                                                                 syn::Type::Path(_) =>
1347                                                                         writeln_opaque(&mut out, &t.ident, &format!("{}", t.ident), &t.generics, &t.attrs, &type_resolver, header_file, cpp_header_file),
1348                                                                 _ => {}
1349                                                         }
1350                                                 }
1351                                         }
1352                                 },
1353                                 syn::Item::Fn(f) => {
1354                                         if let syn::Visibility::Public(_) = f.vis {
1355                                                 writeln_fn(&mut out, &f, &mut type_resolver);
1356                                         }
1357                                 },
1358                                 syn::Item::Macro(m) => {
1359                                         if m.ident.is_none() { // If its not a macro definition
1360                                                 convert_macro(&mut out, &m.mac.path, &m.mac.tokens, &type_resolver);
1361                                         }
1362                                 },
1363                                 syn::Item::Verbatim(_) => {},
1364                                 syn::Item::ExternCrate(_) => {},
1365                                 _ => unimplemented!(),
1366                         }
1367                 }
1368
1369                 out.flush().unwrap();
1370         }
1371 }
1372
1373 /// Insert ident -> absolute Path resolutions into imports from the given UseTree and path-prefix.
1374 fn process_use_intern<'a>(u: &'a syn::UseTree, mut path: syn::punctuated::Punctuated<syn::PathSegment, syn::token::Colon2>, imports: &mut HashMap<&'a syn::Ident, syn::Path>) {
1375         match u {
1376                 syn::UseTree::Path(p) => {
1377                         path.push(syn::PathSegment { ident: p.ident.clone(), arguments: syn::PathArguments::None });
1378                         process_use_intern(&p.tree, path, imports);
1379                 },
1380                 syn::UseTree::Name(n) => {
1381                         path.push(syn::PathSegment { ident: n.ident.clone(), arguments: syn::PathArguments::None });
1382                         imports.insert(&n.ident, syn::Path { leading_colon: Some(syn::Token![::](Span::call_site())), segments: path });
1383                 },
1384                 syn::UseTree::Group(g) => {
1385                         for i in g.items.iter() {
1386                                 process_use_intern(i, path.clone(), imports);
1387                         }
1388                 },
1389                 _ => {}
1390         }
1391 }
1392
1393 /// Map all the Paths in a Type into absolute paths given a set of imports (generated via process_use_intern)
1394 fn resolve_imported_refs(imports: &HashMap<&syn::Ident, syn::Path>, mut ty: syn::Type) -> syn::Type {
1395         match &mut ty {
1396                 syn::Type::Path(p) => {
1397                         if let Some(ident) = p.path.get_ident() {
1398                                 if let Some(newpath) = imports.get(ident) {
1399                                         p.path = newpath.clone();
1400                                 }
1401                         } else { unimplemented!(); }
1402                 },
1403                 syn::Type::Reference(r) => {
1404                         r.elem = Box::new(resolve_imported_refs(imports, (*r.elem).clone()));
1405                 },
1406                 syn::Type::Slice(s) => {
1407                         s.elem = Box::new(resolve_imported_refs(imports, (*s.elem).clone()));
1408                 },
1409                 syn::Type::Tuple(t) => {
1410                         for e in t.elems.iter_mut() {
1411                                 *e = resolve_imported_refs(imports, e.clone());
1412                         }
1413                 },
1414                 _ => unimplemented!(),
1415         }
1416         ty
1417 }
1418
1419 /// Walk the FullLibraryAST, deciding how things will be mapped and adding tracking to CrateTypes.
1420 fn walk_ast<'a>(ast_storage: &'a FullLibraryAST, crate_types: &mut CrateTypes<'a>) {
1421         for (module, astmod) in ast_storage.modules.iter() {
1422                 let ASTModule { ref attrs, ref items, submods: _ } = astmod;
1423                 assert_eq!(export_status(&attrs), ExportStatus::Export);
1424                 let mut import_maps = HashMap::new();
1425
1426                 for item in items.iter() {
1427                         match item {
1428                                 syn::Item::Use(u) => {
1429                                         process_use_intern(&u.tree, syn::punctuated::Punctuated::new(), &mut import_maps);
1430                                 },
1431                                 syn::Item::Struct(s) => {
1432                                         if let syn::Visibility::Public(_) = s.vis {
1433                                                 match export_status(&s.attrs) {
1434                                                         ExportStatus::Export => {},
1435                                                         ExportStatus::NoExport|ExportStatus::TestOnly => continue,
1436                                                 }
1437                                                 let struct_path = format!("{}::{}", module, s.ident);
1438                                                 crate_types.opaques.insert(struct_path, &s.ident);
1439                                         }
1440                                 },
1441                                 syn::Item::Trait(t) => {
1442                                         if let syn::Visibility::Public(_) = t.vis {
1443                                                 match export_status(&t.attrs) {
1444                                                         ExportStatus::Export => {},
1445                                                         ExportStatus::NoExport|ExportStatus::TestOnly => continue,
1446                                                 }
1447                                                 let trait_path = format!("{}::{}", module, t.ident);
1448                                                 walk_supertraits!(t, None, (
1449                                                         ("Clone", _) => {
1450                                                                 crate_types.clonable_types.insert("crate::".to_owned() + &trait_path);
1451                                                         },
1452                                                         (_, _) => {}
1453                                                 ) );
1454                                                 crate_types.traits.insert(trait_path, &t);
1455                                         }
1456                                 },
1457                                 syn::Item::Type(t) => {
1458                                         if let syn::Visibility::Public(_) = t.vis {
1459                                                 match export_status(&t.attrs) {
1460                                                         ExportStatus::Export => {},
1461                                                         ExportStatus::NoExport|ExportStatus::TestOnly => continue,
1462                                                 }
1463                                                 let type_path = format!("{}::{}", module, t.ident);
1464                                                 let mut process_alias = true;
1465                                                 for tok in t.generics.params.iter() {
1466                                                         if let syn::GenericParam::Lifetime(_) = tok {}
1467                                                         else { process_alias = false; }
1468                                                 }
1469                                                 if process_alias {
1470                                                         match &*t.ty {
1471                                                                 syn::Type::Path(_) => {
1472                                                                         // If its a path with no generics, assume we don't map the aliased type and map it opaque
1473                                                                         crate_types.opaques.insert(type_path, &t.ident);
1474                                                                 },
1475                                                                 _ => {
1476                                                                         crate_types.type_aliases.insert(type_path, resolve_imported_refs(&import_maps, (*t.ty).clone()));
1477                                                                 }
1478                                                         }
1479                                                 }
1480                                         }
1481                                 },
1482                                 syn::Item::Enum(e) if is_enum_opaque(e) => {
1483                                         if let syn::Visibility::Public(_) = e.vis {
1484                                                 match export_status(&e.attrs) {
1485                                                         ExportStatus::Export => {},
1486                                                         ExportStatus::NoExport|ExportStatus::TestOnly => continue,
1487                                                 }
1488                                                 let enum_path = format!("{}::{}", module, e.ident);
1489                                                 crate_types.opaques.insert(enum_path, &e.ident);
1490                                         }
1491                                 },
1492                                 syn::Item::Enum(e) => {
1493                                         if let syn::Visibility::Public(_) = e.vis {
1494                                                 match export_status(&e.attrs) {
1495                                                         ExportStatus::Export => {},
1496                                                         ExportStatus::NoExport|ExportStatus::TestOnly => continue,
1497                                                 }
1498                                                 let enum_path = format!("{}::{}", module, e.ident);
1499                                                 crate_types.mirrored_enums.insert(enum_path, &e);
1500                                         }
1501                                 },
1502                                 syn::Item::Impl(i) => {
1503                                         if let &syn::Type::Path(ref p) = &*i.self_ty {
1504                                                 if let Some(trait_path) = i.trait_.as_ref() {
1505                                                         if path_matches_nongeneric(&trait_path.1, &["core", "clone", "Clone"]) {
1506                                                                 // Note, we should probably have more full-featured type resolution here,
1507                                                                 // but for now we don't have any cases where we impl X for A::B.
1508                                                                 let ident = single_ident_generic_path_to_ident(&p.path).expect("impl X for A::B currently unsupported");
1509                                                                 assert!(import_maps.get(&ident).is_none());
1510                                                                 crate_types.clonable_types.insert(format!("crate::{}::{}", module, ident));
1511                                                         }
1512                                                 }
1513                                         }
1514                                 },
1515                                 _ => {},
1516                         }
1517                 }
1518         }
1519 }
1520
1521 fn main() {
1522         let args: Vec<String> = env::args().collect();
1523         if args.len() != 6 {
1524                 eprintln!("Usage: target/dir source_crate_name derived_templates.rs extra/includes.h extra/cpp/includes.hpp");
1525                 process::exit(1);
1526         }
1527
1528         let mut derived_templates = std::fs::OpenOptions::new().write(true).create(true).truncate(true)
1529                 .open(&args[3]).expect("Unable to open new header file");
1530         let mut header_file = std::fs::OpenOptions::new().write(true).create(true).truncate(true)
1531                 .open(&args[4]).expect("Unable to open new header file");
1532         let mut cpp_header_file = std::fs::OpenOptions::new().write(true).create(true).truncate(true)
1533                 .open(&args[5]).expect("Unable to open new header file");
1534
1535         writeln!(header_file, "#if defined(__GNUC__)").unwrap();
1536         writeln!(header_file, "#define MUST_USE_STRUCT __attribute__((warn_unused))").unwrap();
1537         writeln!(header_file, "#define MUST_USE_RES __attribute__((warn_unused_result))").unwrap();
1538         writeln!(header_file, "#else").unwrap();
1539         writeln!(header_file, "#define MUST_USE_STRUCT").unwrap();
1540         writeln!(header_file, "#define MUST_USE_RES").unwrap();
1541         writeln!(header_file, "#endif").unwrap();
1542         writeln!(header_file, "#if defined(__clang__)").unwrap();
1543         writeln!(header_file, "#define NONNULL_PTR _Nonnull").unwrap();
1544         writeln!(header_file, "#else").unwrap();
1545         writeln!(header_file, "#define NONNULL_PTR").unwrap();
1546         writeln!(header_file, "#endif").unwrap();
1547         writeln!(cpp_header_file, "#include <string.h>\nnamespace LDK {{").unwrap();
1548
1549         // First parse the full crate's ASTs, caching them so that we can hold references to the AST
1550         // objects in other datastructures:
1551         let mut lib_src = String::new();
1552         std::io::stdin().lock().read_to_string(&mut lib_src).unwrap();
1553         let lib_syntax = syn::parse_file(&lib_src).expect("Unable to parse file");
1554         let libast = FullLibraryAST::load_lib(lib_syntax);
1555
1556         // ...then walk the ASTs tracking what types we will map, and how, so that we can resolve them
1557         // when parsing other file ASTs...
1558         let mut libtypes = CrateTypes { traits: HashMap::new(), opaques: HashMap::new(), mirrored_enums: HashMap::new(),
1559                 type_aliases: HashMap::new(), templates_defined: HashMap::default(), template_file: &mut derived_templates,
1560                 clonable_types: HashSet::new() };
1561         walk_ast(&libast, &mut libtypes);
1562
1563         // ... finally, do the actual file conversion/mapping, writing out types as we go.
1564         convert_file(&libast, &mut libtypes, &args[1], &args[2], &mut header_file, &mut cpp_header_file);
1565
1566         // For container templates which we created while walking the crate, make sure we add C++
1567         // mapped types so that C++ users can utilize the auto-destructors available.
1568         for (ty, has_destructor) in libtypes.templates_defined.iter() {
1569                 write_cpp_wrapper(&mut cpp_header_file, ty, *has_destructor);
1570         }
1571         writeln!(cpp_header_file, "}}").unwrap();
1572
1573         header_file.flush().unwrap();
1574         cpp_header_file.flush().unwrap();
1575         derived_templates.flush().unwrap();
1576 }