_ 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;
  14 use std::env;
  15 use std::fs::File;
  16 use std::io::{Read, Write};
  17 use std::path::Path;
  18 use std::process;
  19
  20 use proc_macro2::{TokenTree, TokenStream, Span};
  21
  22 mod types;
  23 mod blocks;
  24 use types::*;
  25 use blocks::*;
  26
  27 // *************************************
  28 // *** Manually-expanded conversions ***
  29 // *************************************
  30
  31 /// Because we don't expand macros, any code that we need to generated based on their contents has
  32 /// to be completely manual. In this case its all just serialization, so its not too hard.
  33 fn convert_macro<W: std::io::Write>(w: &mut W, macro_path: &syn::Path, stream: &TokenStream, types: &TypeResolver) {
  34         assert_eq!(macro_path.segments.len(), 1);
  35         match &format!("{}", macro_path.segments.iter().next().unwrap().ident) as &str {
  36                 "impl_writeable" | "impl_writeable_len_match" => {
  37                         let struct_for = if let TokenTree::Ident(i) = stream.clone().into_iter().next().unwrap() { i } else { unimplemented!(); };
  38                         if let Some(s) = types.maybe_resolve_ident(&struct_for) {
  39                                 if !types.crate_types.opaques.get(&s).is_some() { return; }
  40                                 writeln!(w, "#[no_mangle]").unwrap();
  41                                 writeln!(w, "pub extern \"C\" fn {}_write(obj: *const {}) -> crate::c_types::derived::CVec_u8Z {{", struct_for, struct_for).unwrap();
  42                                 writeln!(w, "\tcrate::c_types::serialize_obj(unsafe {{ &(*(*obj).inner) }})").unwrap();
  43                                 writeln!(w, "}}").unwrap();
  44                                 writeln!(w, "#[no_mangle]").unwrap();
  45                                 writeln!(w, "pub(crate) extern \"C\" fn {}_write_void(obj: *const c_void) -> crate::c_types::derived::CVec_u8Z {{", struct_for).unwrap();
  46                                 writeln!(w, "\tcrate::c_types::serialize_obj(unsafe {{ &*(obj as *const native{}) }})", struct_for).unwrap();
  47                                 writeln!(w, "}}").unwrap();
  48                                 writeln!(w, "#[no_mangle]").unwrap();
  49                                 writeln!(w, "pub extern \"C\" fn {}_read(ser: crate::c_types::u8slice) -> {} {{", struct_for, struct_for).unwrap();
  50                                 writeln!(w, "\tif let Ok(res) = crate::c_types::deserialize_obj(ser) {{").unwrap();
  51                                 writeln!(w, "\t\t{} {{ inner: Box::into_raw(Box::new(res)), is_owned: true }}", struct_for).unwrap();
  52                                 writeln!(w, "\t}} else {{").unwrap();
  53                                 writeln!(w, "\t\t{} {{ inner: std::ptr::null_mut(), is_owned: true }}", struct_for).unwrap();
  54                                 writeln!(w, "\t}}\n}}").unwrap();
  55                         }
  56                 },
  57                 _ => {},
  58         }
  59 }
  60
  61 /// Convert "impl trait_path for for_ty { .. }" for manually-mapped types (ie (de)serialization)
  62 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) {
  63         if let Some(t) = types.maybe_resolve_path(&trait_path, Some(generics)) {
  64                 let for_obj;
  65                 let full_obj_path;
  66                 let mut has_inner = false;
  67                 if let syn::Type::Path(ref p) = for_ty {
  68                         if let Some(ident) = single_ident_generic_path_to_ident(&p.path) {
  69                                 for_obj = format!("{}", ident);
  70                                 full_obj_path = for_obj.clone();
  71                                 has_inner = types.c_type_has_inner_from_path(&types.resolve_path(&p.path, Some(generics)));
  72                         } else { return; }
  73                 } else {
  74                         // We assume that anything that isn't a Path is somehow a generic that ends up in our
  75                         // derived-types module.
  76                         let mut for_obj_vec = Vec::new();
  77                         types.write_c_type(&mut for_obj_vec, for_ty, Some(generics), false);
  78                         full_obj_path = String::from_utf8(for_obj_vec).unwrap();
  79                         assert!(full_obj_path.starts_with(TypeResolver::generated_container_path()));
  80                         for_obj = full_obj_path[TypeResolver::generated_container_path().len() + 2..].into();
  81                 }
  82
  83                 match &t as &str {
  84                         "util::ser::Writeable" => {
  85                                 writeln!(w, "#[no_mangle]").unwrap();
  86                                 writeln!(w, "pub extern \"C\" fn {}_write(obj: *const {}) -> crate::c_types::derived::CVec_u8Z {{", for_obj, full_obj_path).unwrap();
  87
  88                                 let ref_type = syn::Type::Reference(syn::TypeReference {
  89                                         and_token: syn::Token!(&)(Span::call_site()), lifetime: None, mutability: None,
  90                                         elem: Box::new(for_ty.clone()) });
  91                                 assert!(!types.write_from_c_conversion_new_var(w, &syn::Ident::new("obj", Span::call_site()), &ref_type, Some(generics)));
  92
  93                                 write!(w, "\tcrate::c_types::serialize_obj(").unwrap();
  94                                 types.write_from_c_conversion_prefix(w, &ref_type, Some(generics));
  95                                 write!(w, "unsafe {{ &*obj }}").unwrap();
  96                                 types.write_from_c_conversion_suffix(w, &ref_type, Some(generics));
  97                                 writeln!(w, ")").unwrap();
  98
  99                                 writeln!(w, "}}").unwrap();
 100                                 if has_inner {
 101                                         writeln!(w, "#[no_mangle]").unwrap();
 102                                         writeln!(w, "pub(crate) extern \"C\" fn {}_write_void(obj: *const c_void) -> crate::c_types::derived::CVec_u8Z {{", for_obj).unwrap();
 103                                         writeln!(w, "\tcrate::c_types::serialize_obj(unsafe {{ &*(obj as *const native{}) }})", for_obj).unwrap();
 104                                         writeln!(w, "}}").unwrap();
 105                                 }
 106                         },
 107                         "util::ser::Readable"|"util::ser::ReadableArgs" => {
 108                                 // Create the Result<Object, DecodeError> syn::Type
 109                                 let mut err_segs = syn::punctuated::Punctuated::new();
 110                                 err_segs.push(syn::PathSegment { ident: syn::Ident::new("ln", Span::call_site()), arguments: syn::PathArguments::None });
 111                                 err_segs.push(syn::PathSegment { ident: syn::Ident::new("msgs", Span::call_site()), arguments: syn::PathArguments::None });
 112                                 err_segs.push(syn::PathSegment { ident: syn::Ident::new("DecodeError", Span::call_site()), arguments: syn::PathArguments::None });
 113                                 let mut args = syn::punctuated::Punctuated::new();
 114                                 args.push(syn::GenericArgument::Type(for_ty.clone()));
 115                                 args.push(syn::GenericArgument::Type(syn::Type::Path(syn::TypePath {
 116                                         qself: None, path: syn::Path {
 117                                                 leading_colon: Some(syn::Token![::](Span::call_site())), segments: err_segs,
 118                                         }
 119                                 })));
 120                                 let mut res_segs = syn::punctuated::Punctuated::new();
 121                                 res_segs.push(syn::PathSegment {
 122                                         ident: syn::Ident::new("Result", Span::call_site()),
 123                                         arguments: syn::PathArguments::AngleBracketed(syn::AngleBracketedGenericArguments {
 124                                                 colon2_token: None, lt_token: syn::Token![<](Span::call_site()), args, gt_token: syn::Token![>](Span::call_site()),
 125                                         })
 126                                 });
 127                                 let res_ty = syn::Type::Path(syn::TypePath { qself: None, path: syn::Path {
 128                                         leading_colon: None, segments: res_segs } });
 129
 130                                 writeln!(w, "#[no_mangle]").unwrap();
 131                                 write!(w, "pub extern \"C\" fn {}_read(ser: crate::c_types::u8slice", for_obj).unwrap();
 132
 133                                 let mut arg_conv = Vec::new();
 134                                 if t == "util::ser::ReadableArgs" {
 135                                         write!(w, ", arg: ").unwrap();
 136                                         assert!(trait_path.leading_colon.is_none());
 137                                         let args_seg = trait_path.segments.iter().last().unwrap();
 138                                         assert_eq!(format!("{}", args_seg.ident), "ReadableArgs");
 139                                         if let syn::PathArguments::AngleBracketed(args) = &args_seg.arguments {
 140                                                 assert_eq!(args.args.len(), 1);
 141                                                 if let syn::GenericArgument::Type(args_ty) = args.args.iter().next().unwrap() {
 142                                                         types.write_c_type(w, args_ty, Some(generics), false);
 143
 144                                                         assert!(!types.write_from_c_conversion_new_var(&mut arg_conv, &syn::Ident::new("arg", Span::call_site()), &args_ty, Some(generics)));
 145
 146                                                         write!(&mut arg_conv, "\tlet arg_conv = ").unwrap();
 147                                                         types.write_from_c_conversion_prefix(&mut arg_conv, &args_ty, Some(generics));
 148                                                         write!(&mut arg_conv, "arg").unwrap();
 149                                                         types.write_from_c_conversion_suffix(&mut arg_conv, &args_ty, Some(generics));
 150                                                 } else { unreachable!(); }
 151                                         } else { unreachable!(); }
 152                                 }
 153                                 write!(w, ") -> ").unwrap();
 154                                 types.write_c_type(w, &res_ty, Some(generics), false);
 155                                 writeln!(w, " {{").unwrap();
 156
 157                                 if t == "util::ser::ReadableArgs" {
 158                                         w.write(&arg_conv).unwrap();
 159                                         write!(w, ";\n\tlet res: ").unwrap();
 160                                         // At least in one case we need type annotations here, so provide them.
 161                                         types.write_rust_type(w, Some(generics), &res_ty);
 162                                         writeln!(w, " = crate::c_types::deserialize_obj_arg(ser, arg_conv);").unwrap();
 163                                 } else {
 164                                         writeln!(w, "\tlet res = crate::c_types::deserialize_obj(ser);").unwrap();
 165                                 }
 166                                 write!(w, "\t").unwrap();
 167                                 if types.write_to_c_conversion_new_var(w, &syn::Ident::new("res", Span::call_site()), &res_ty, Some(generics), false) {
 168                                         write!(w, "\n\t").unwrap();
 169                                 }
 170                                 types.write_to_c_conversion_inline_prefix(w, &res_ty, Some(generics), false);
 171                                 write!(w, "res").unwrap();
 172                                 types.write_to_c_conversion_inline_suffix(w, &res_ty, Some(generics), false);
 173                                 writeln!(w, "\n}}").unwrap();
 174                         },
 175                         _ => {},
 176                 }
 177         }
 178 }
 179
 180 /// Convert "TraitA : TraitB" to a single function name and return type.
 181 ///
 182 /// This is (obviously) somewhat over-specialized and only useful for TraitB's that only require a
 183 /// single function (eg for serialization).
 184 fn convert_trait_impl_field(trait_path: &str) -> (String, &'static str) {
 185         match trait_path {
 186                 "util::ser::Writeable" => ("write".to_owned(), "crate::c_types::derived::CVec_u8Z"),
 187                 _ => unimplemented!(),
 188         }
 189 }
 190
 191 /// Companion to convert_trait_impl_field, write an assignment for the function defined by it for
 192 /// `for_obj` which implements the the trait at `trait_path`.
 193 fn write_trait_impl_field_assign<W: std::io::Write>(w: &mut W, trait_path: &str, for_obj: &syn::Ident) {
 194         match trait_path {
 195                 "util::ser::Writeable" => {
 196                         writeln!(w, "\t\twrite: {}_write_void,", for_obj).unwrap();
 197                 },
 198                 _ => unimplemented!(),
 199         }
 200 }
 201
 202 /// Write out the impl block for a defined trait struct which has a supertrait
 203 fn do_write_impl_trait<W: std::io::Write>(w: &mut W, trait_path: &str, trait_name: &syn::Ident, for_obj: &str) {
 204         match trait_path {
 205                 "util::events::MessageSendEventsProvider" => {
 206                         writeln!(w, "impl lightning::{} for {} {{", trait_path, for_obj).unwrap();
 207                         writeln!(w, "\tfn get_and_clear_pending_msg_events(&self) -> Vec<lightning::util::events::MessageSendEvent> {{").unwrap();
 208                         writeln!(w, "\t\t<crate::{} as lightning::{}>::get_and_clear_pending_msg_events(&self.{})", trait_path, trait_path, trait_name).unwrap();
 209                         writeln!(w, "\t}}\n}}").unwrap();
 210                 },
 211                 "util::ser::Writeable" => {
 212                         writeln!(w, "impl lightning::{} for {} {{", trait_path, for_obj).unwrap();
 213                         writeln!(w, "\tfn write<W: lightning::util::ser::Writer>(&self, w: &mut W) -> Result<(), ::std::io::Error> {{").unwrap();
 214                         writeln!(w, "\t\tlet vec = (self.write)(self.this_arg);").unwrap();
 215                         writeln!(w, "\t\tw.write_all(vec.as_slice())").unwrap();
 216                         writeln!(w, "\t}}\n}}").unwrap();
 217                 },
 218                 _ => panic!(),
 219         }
 220 }
 221
 222 // *******************************
 223 // *** Per-Type Printing Logic ***
 224 // *******************************
 225
 226 macro_rules! walk_supertraits { ($t: expr, $types: expr, ($( $pat: pat => $e: expr),*) ) => { {
 227         if $t.colon_token.is_some() {
 228                 for st in $t.supertraits.iter() {
 229                         match st {
 230                                 syn::TypeParamBound::Trait(supertrait) => {
 231                                         if supertrait.paren_token.is_some() || supertrait.lifetimes.is_some() {
 232                                                 unimplemented!();
 233                                         }
 234                                         // First try to resolve path to find in-crate traits, but if that doesn't work
 235                                         // assume its a prelude trait (eg Clone, etc) and just use the single ident.
 236                                         if let Some(path) = $types.maybe_resolve_path(&supertrait.path, None) {
 237                                                 match (&path as &str, &supertrait.path.segments.iter().last().unwrap().ident) {
 238                                                         $( $pat => $e, )*
 239                                                 }
 240                                         } else if let Some(ident) = supertrait.path.get_ident() {
 241                                                 match (&format!("{}", ident) as &str, &ident) {
 242                                                         $( $pat => $e, )*
 243                                                 }
 244                                         } else {
 245                                                 panic!("Supertrait unresolvable and not single-ident");
 246                                         }
 247                                 },
 248                                 syn::TypeParamBound::Lifetime(_) => unimplemented!(),
 249                         }
 250                 }
 251         }
 252 } } }
 253
 254 /// Prints a C-mapped trait object containing a void pointer and a jump table for each function in
 255 /// the original trait.
 256 /// Implements the native Rust trait and relevant parent traits for the new C-mapped trait.
 257 ///
 258 /// Finally, implements Deref<MappedTrait> for MappedTrait which allows its use in types which need
 259 /// a concrete Deref to the Rust trait.
 260 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) {
 261         let trait_name = format!("{}", t.ident);
 262         match export_status(&t.attrs) {
 263                 ExportStatus::Export => {},
 264                 ExportStatus::NoExport|ExportStatus::TestOnly => return,
 265         }
 266         writeln_docs(w, &t.attrs, "");
 267
 268         let mut gen_types = GenericTypes::new();
 269         assert!(gen_types.learn_generics(&t.generics, types));
 270         gen_types.learn_associated_types(&t, types);
 271
 272         writeln!(w, "#[repr(C)]\npub struct {} {{", trait_name).unwrap();
 273         writeln!(w, "\tpub this_arg: *mut c_void,").unwrap();
 274         let mut generated_fields = Vec::new(); // Every field's name except this_arg, used in Clone generation
 275         for item in t.items.iter() {
 276                 match item {
 277                         &syn::TraitItem::Method(ref m) => {
 278                                 match export_status(&m.attrs) {
 279                                         ExportStatus::NoExport => {
 280                                                 // NoExport in this context means we'll hit an unimplemented!() at runtime,
 281                                                 // so bail out.
 282                                                 unimplemented!();
 283                                         },
 284                                         ExportStatus::Export => {},
 285                                         ExportStatus::TestOnly => continue,
 286                                 }
 287                                 if m.default.is_some() { unimplemented!(); }
 288
 289                                 gen_types.push_ctx();
 290                                 assert!(gen_types.learn_generics(&m.sig.generics, types));
 291
 292                                 writeln_docs(w, &m.attrs, "\t");
 293
 294                                 if let syn::ReturnType::Type(_, rtype) = &m.sig.output {
 295                                         if let syn::Type::Reference(r) = &**rtype {
 296                                                 // We have to do quite a dance for trait functions which return references
 297                                                 // - they ultimately require us to have a native Rust object stored inside
 298                                                 // our concrete trait to return a reference to. However, users may wish to
 299                                                 // update the value to be returned each time the function is called (or, to
 300                                                 // make C copies of Rust impls equivalent, we have to be able to).
 301                                                 //
 302                                                 // Thus, we store a copy of the C-mapped type (which is just a pointer to
 303                                                 // the Rust type and a flag to indicate whether deallocation needs to
 304                                                 // happen) as well as provide an Option<>al function pointer which is
 305                                                 // called when the trait method is called which allows updating on the fly.
 306                                                 write!(w, "\tpub {}: ", m.sig.ident).unwrap();
 307                                                 generated_fields.push(format!("{}", m.sig.ident));
 308                                                 types.write_c_type(w, &*r.elem, Some(&gen_types), false);
 309                                                 writeln!(w, ",").unwrap();
 310                                                 writeln!(w, "\t/// Fill in the {} field as a reference to it will be given to Rust after this returns", m.sig.ident).unwrap();
 311                                                 writeln!(w, "\t/// Note that this takes a pointer to this object, not the this_ptr like other methods do").unwrap();
 312                                                 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();
 313                                                 writeln!(w, "\tpub set_{}: Option<extern \"C\" fn(&{})>,", m.sig.ident, trait_name).unwrap();
 314                                                 generated_fields.push(format!("set_{}", m.sig.ident));
 315                                                 // Note that cbindgen will now generate
 316                                                 // typedef struct Thing {..., set_thing: (const Thing*), ...} Thing;
 317                                                 // which does not compile since Thing is not defined before it is used.
 318                                                 writeln!(extra_headers, "struct LDK{};", trait_name).unwrap();
 319                                                 writeln!(extra_headers, "typedef struct LDK{} LDK{};", trait_name, trait_name).unwrap();
 320                                                 gen_types.pop_ctx();
 321                                                 continue;
 322                                         }
 323                                         // Sadly, this currently doesn't do what we want, but it should be easy to get
 324                                         // cbindgen to support it. See https://github.com/eqrion/cbindgen/issues/531
 325                                         writeln!(w, "\t#[must_use]").unwrap();
 326                                 }
 327
 328                                 write!(w, "\tpub {}: extern \"C\" fn (", m.sig.ident).unwrap();
 329                                 generated_fields.push(format!("{}", m.sig.ident));
 330                                 write_method_params(w, &m.sig, "c_void", types, Some(&gen_types), true, false);
 331                                 writeln!(w, ",").unwrap();
 332
 333                                 gen_types.pop_ctx();
 334                         },
 335                         &syn::TraitItem::Type(_) => {},
 336                         _ => unimplemented!(),
 337                 }
 338         }
 339         // Add functions which may be required for supertrait implementations.
 340         walk_supertraits!(t, types, (
 341                 ("Clone", _) => {
 342                         writeln!(w, "\tpub clone: Option<extern \"C\" fn (this_arg: *const c_void) -> *mut c_void>,").unwrap();
 343                         generated_fields.push("clone".to_owned());
 344                 },
 345                 ("std::cmp::Eq", _) => {
 346                         writeln!(w, "\tpub eq: extern \"C\" fn (this_arg: *const c_void, other_arg: &{}) -> bool,", trait_name).unwrap();
 347                         writeln!(extra_headers, "typedef struct LDK{} LDK{};", trait_name, trait_name).unwrap();
 348                         generated_fields.push("eq".to_owned());
 349                 },
 350                 ("std::hash::Hash", _) => {
 351                         writeln!(w, "\tpub hash: extern \"C\" fn (this_arg: *const c_void) -> u64,").unwrap();
 352                         generated_fields.push("hash".to_owned());
 353                 },
 354                 ("Send", _) => {}, ("Sync", _) => {},
 355                 (s, i) => {
 356                         generated_fields.push(if types.crate_types.traits.get(s).is_none() {
 357                                 let (name, ret) = convert_trait_impl_field(s);
 358                                 writeln!(w, "\tpub {}: extern \"C\" fn (this_arg: *const c_void) -> {},", name, ret).unwrap();
 359                                 name
 360                         } else {
 361                                 // For in-crate supertraits, just store a C-mapped copy of the supertrait as a member.
 362                                 writeln!(w, "\tpub {}: crate::{},", i, s).unwrap();
 363                                 format!("{}", i)
 364                         });
 365                 }
 366         ) );
 367         writeln!(w, "\tpub free: Option<extern \"C\" fn(this_arg: *mut c_void)>,").unwrap();
 368         generated_fields.push("free".to_owned());
 369         writeln!(w, "}}").unwrap();
 370         // Implement supertraits for the C-mapped struct.
 371         walk_supertraits!(t, types, (
 372                 ("Send", _) => writeln!(w, "unsafe impl Send for {} {{}}", trait_name).unwrap(),
 373                 ("Sync", _) => writeln!(w, "unsafe impl Sync for {} {{}}", trait_name).unwrap(),
 374                 ("std::cmp::Eq", _) => {
 375                         writeln!(w, "impl std::cmp::Eq for {} {{}}", trait_name).unwrap();
 376                         writeln!(w, "impl std::cmp::PartialEq for {} {{", trait_name).unwrap();
 377                         writeln!(w, "\tfn eq(&self, o: &Self) -> bool {{ (self.eq)(self.this_arg, o) }}\n}}").unwrap();
 378                 },
 379                 ("std::hash::Hash", _) => {
 380                         writeln!(w, "impl std::hash::Hash for {} {{", trait_name).unwrap();
 381                         writeln!(w, "\tfn hash<H: std::hash::Hasher>(&self, hasher: &mut H) {{ hasher.write_u64((self.hash)(self.this_arg)) }}\n}}").unwrap();
 382                 },
 383                 ("Clone", _) => {
 384                         writeln!(w, "#[no_mangle]").unwrap();
 385                         writeln!(w, "pub extern \"C\" fn {}_clone(orig: &{}) -> {} {{", trait_name, trait_name, trait_name).unwrap();
 386                         writeln!(w, "\t{} {{", trait_name).unwrap();
 387                         writeln!(w, "\t\tthis_arg: if let Some(f) = orig.clone {{ (f)(orig.this_arg) }} else {{ orig.this_arg }},").unwrap();
 388                         for field in generated_fields.iter() {
 389                                 writeln!(w, "\t\t{}: orig.{}.clone(),", field, field).unwrap();
 390                         }
 391                         writeln!(w, "\t}}\n}}").unwrap();
 392                         writeln!(w, "impl Clone for {} {{", trait_name).unwrap();
 393                         writeln!(w, "\tfn clone(&self) -> Self {{").unwrap();
 394                         writeln!(w, "\t\t{}_clone(self)", trait_name).unwrap();
 395                         writeln!(w, "\t}}\n}}").unwrap();
 396                 },
 397                 (s, i) => {
 398                         do_write_impl_trait(w, s, i, &trait_name);
 399                 }
 400         ) );
 401
 402         // Finally, implement the original Rust trait for the newly created mapped trait.
 403         writeln!(w, "\nuse {}::{}::{} as rust{};", types.orig_crate, types.module_path, t.ident, trait_name).unwrap();
 404         write!(w, "impl rust{}", t.ident).unwrap();
 405         maybe_write_generics(w, &t.generics, types, false);
 406         writeln!(w, " for {} {{", trait_name).unwrap();
 407         for item in t.items.iter() {
 408                 match item {
 409                         syn::TraitItem::Method(m) => {
 410                                 if let ExportStatus::TestOnly = export_status(&m.attrs) { continue; }
 411                                 if m.default.is_some() { unimplemented!(); }
 412                                 if m.sig.constness.is_some() || m.sig.asyncness.is_some() || m.sig.unsafety.is_some() ||
 413                                                 m.sig.abi.is_some() || m.sig.variadic.is_some() {
 414                                         unimplemented!();
 415                                 }
 416                                 gen_types.push_ctx();
 417                                 assert!(gen_types.learn_generics(&m.sig.generics, types));
 418                                 write!(w, "\tfn {}", m.sig.ident).unwrap();
 419                                 types.write_rust_generic_param(w, Some(&gen_types), m.sig.generics.params.iter());
 420                                 write!(w, "(").unwrap();
 421                                 for inp in m.sig.inputs.iter() {
 422                                         match inp {
 423                                                 syn::FnArg::Receiver(recv) => {
 424                                                         if !recv.attrs.is_empty() || recv.reference.is_none() { unimplemented!(); }
 425                                                         write!(w, "&").unwrap();
 426                                                         if let Some(lft) = &recv.reference.as_ref().unwrap().1 {
 427                                                                 write!(w, "'{} ", lft.ident).unwrap();
 428                                                         }
 429                                                         if recv.mutability.is_some() {
 430                                                                 write!(w, "mut self").unwrap();
 431                                                         } else {
 432                                                                 write!(w, "self").unwrap();
 433                                                         }
 434                                                 },
 435                                                 syn::FnArg::Typed(arg) => {
 436                                                         if !arg.attrs.is_empty() { unimplemented!(); }
 437                                                         match &*arg.pat {
 438                                                                 syn::Pat::Ident(ident) => {
 439                                                                         if !ident.attrs.is_empty() || ident.by_ref.is_some() ||
 440                                                                                         ident.mutability.is_some() || ident.subpat.is_some() {
 441                                                                                 unimplemented!();
 442                                                                         }
 443                                                                         write!(w, ", {}{}: ", if types.skip_arg(&*arg.ty, Some(&gen_types)) { "_" } else { "" }, ident.ident).unwrap();
 444                                                                 }
 445                                                                 _ => unimplemented!(),
 446                                                         }
 447                                                         types.write_rust_type(w, Some(&gen_types), &*arg.ty);
 448                                                 }
 449                                         }
 450                                 }
 451                                 write!(w, ")").unwrap();
 452                                 match &m.sig.output {
 453                                         syn::ReturnType::Type(_, rtype) => {
 454                                                 write!(w, " -> ").unwrap();
 455                                                 types.write_rust_type(w, Some(&gen_types), &*rtype)
 456                                         },
 457                                         _ => {},
 458                                 }
 459                                 write!(w, " {{\n\t\t").unwrap();
 460                                 match export_status(&m.attrs) {
 461                                         ExportStatus::NoExport => {
 462                                                 unimplemented!();
 463                                         },
 464                                         _ => {},
 465                                 }
 466                                 if let syn::ReturnType::Type(_, rtype) = &m.sig.output {
 467                                         if let syn::Type::Reference(r) = &**rtype {
 468                                                 assert_eq!(m.sig.inputs.len(), 1); // Must only take self!
 469                                                 writeln!(w, "if let Some(f) = self.set_{} {{", m.sig.ident).unwrap();
 470                                                 writeln!(w, "\t\t\t(f)(self);").unwrap();
 471                                                 write!(w, "\t\t}}\n\t\t").unwrap();
 472                                                 types.write_from_c_conversion_to_ref_prefix(w, &*r.elem, Some(&gen_types));
 473                                                 write!(w, "self.{}", m.sig.ident).unwrap();
 474                                                 types.write_from_c_conversion_to_ref_suffix(w, &*r.elem, Some(&gen_types));
 475                                                 writeln!(w, "\n\t}}").unwrap();
 476                                                 gen_types.pop_ctx();
 477                                                 continue;
 478                                         }
 479                                 }
 480                                 write_method_var_decl_body(w, &m.sig, "\t", types, Some(&gen_types), true);
 481                                 write!(w, "(self.{})(", m.sig.ident).unwrap();
 482                                 write_method_call_params(w, &m.sig, "\t", types, Some(&gen_types), "", true);
 483
 484                                 writeln!(w, "\n\t}}").unwrap();
 485                                 gen_types.pop_ctx();
 486                         },
 487                         &syn::TraitItem::Type(ref t) => {
 488                                 if t.default.is_some() || t.generics.lt_token.is_some() { unimplemented!(); }
 489                                 let mut bounds_iter = t.bounds.iter();
 490                                 match bounds_iter.next().unwrap() {
 491                                         syn::TypeParamBound::Trait(tr) => {
 492                                                 writeln!(w, "\ttype {} = crate::{};", t.ident, types.resolve_path(&tr.path, Some(&gen_types))).unwrap();
 493                                         },
 494                                         _ => unimplemented!(),
 495                                 }
 496                                 if bounds_iter.next().is_some() { unimplemented!(); }
 497                         },
 498                         _ => unimplemented!(),
 499                 }
 500         }
 501         writeln!(w, "}}\n").unwrap();
 502         writeln!(w, "// We're essentially a pointer already, or at least a set of pointers, so allow us to be used").unwrap();
 503         writeln!(w, "// directly as a Deref trait in higher-level structs:").unwrap();
 504         writeln!(w, "impl std::ops::Deref for {} {{\n\ttype Target = Self;", trait_name).unwrap();
 505         writeln!(w, "\tfn deref(&self) -> &Self {{\n\t\tself\n\t}}\n}}").unwrap();
 506
 507         writeln!(w, "/// Calls the free function if one is set").unwrap();
 508         writeln!(w, "#[no_mangle]\npub extern \"C\" fn {}_free(this_ptr: {}) {{ }}", trait_name, trait_name).unwrap();
 509         writeln!(w, "impl Drop for {} {{", trait_name).unwrap();
 510         writeln!(w, "\tfn drop(&mut self) {{").unwrap();
 511         writeln!(w, "\t\tif let Some(f) = self.free {{").unwrap();
 512         writeln!(w, "\t\t\tf(self.this_arg);").unwrap();
 513         writeln!(w, "\t\t}}\n\t}}\n}}").unwrap();
 514
 515         write_cpp_wrapper(cpp_headers, &trait_name, true);
 516         types.trait_declared(&t.ident, t);
 517 }
 518
 519 /// Write out a simple "opaque" type (eg structs) which contain a pointer to the native Rust type
 520 /// and a flag to indicate whether Drop'ing the mapped struct drops the underlying Rust type.
 521 ///
 522 /// Also writes out a _free function and a C++ wrapper which handles calling _free.
 523 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) {
 524         // If we directly read the original type by its original name, cbindgen hits
 525         // https://github.com/eqrion/cbindgen/issues/286 Thus, instead, we import it as a temporary
 526         // name and then reference it by that name, which works around the issue.
 527         write!(w, "\nuse {}::{}::{} as native{}Import;\ntype native{} = native{}Import", types.orig_crate, types.module_path, ident, ident, ident, ident).unwrap();
 528         maybe_write_generics(w, &generics, &types, true);
 529         writeln!(w, ";\n").unwrap();
 530         writeln!(extra_headers, "struct native{}Opaque;\ntypedef struct native{}Opaque LDKnative{};", ident, ident, ident).unwrap();
 531         writeln_docs(w, &attrs, "");
 532         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();
 533         writeln!(w, "\t/// the Rust equivalent takes an Option, it may be set to null to indicate None.").unwrap();
 534         writeln!(w, "\tpub inner: *mut native{},\n\tpub is_owned: bool,\n}}\n", ident).unwrap();
 535         writeln!(w, "impl Drop for {} {{\n\tfn drop(&mut self) {{", struct_name).unwrap();
 536         writeln!(w, "\t\tif self.is_owned && !self.inner.is_null() {{").unwrap();
 537         writeln!(w, "\t\t\tlet _ = unsafe {{ Box::from_raw(self.inner) }};\n\t\t}}\n\t}}\n}}").unwrap();
 538         writeln!(w, "#[no_mangle]\npub extern \"C\" fn {}_free(this_ptr: {}) {{ }}", struct_name, struct_name).unwrap();
 539         writeln!(w, "#[allow(unused)]").unwrap();
 540         writeln!(w, "/// Used only if an object of this type is returned as a trait impl by a method").unwrap();
 541         writeln!(w, "extern \"C\" fn {}_free_void(this_ptr: *mut c_void) {{", struct_name).unwrap();
 542         writeln!(w, "\tunsafe {{ let _ = Box::from_raw(this_ptr as *mut native{}); }}\n}}", struct_name).unwrap();
 543         writeln!(w, "#[allow(unused)]").unwrap();
 544         writeln!(w, "/// When moving out of the pointer, we have to ensure we aren't a reference, this makes that easy").unwrap();
 545         writeln!(w, "impl {} {{", struct_name).unwrap();
 546         writeln!(w, "\tpub(crate) fn take_inner(mut self) -> *mut native{} {{", struct_name).unwrap();
 547         writeln!(w, "\t\tassert!(self.is_owned);").unwrap();
 548         writeln!(w, "\t\tlet ret = self.inner;").unwrap();
 549         writeln!(w, "\t\tself.inner = std::ptr::null_mut();").unwrap();
 550         writeln!(w, "\t\tret").unwrap();
 551         writeln!(w, "\t}}\n}}").unwrap();
 552
 553         'attr_loop: for attr in attrs.iter() {
 554                 let tokens_clone = attr.tokens.clone();
 555                 let mut token_iter = tokens_clone.into_iter();
 556                 if let Some(token) = token_iter.next() {
 557                         match token {
 558                                 TokenTree::Group(g) => {
 559                                         if format!("{}", single_ident_generic_path_to_ident(&attr.path).unwrap()) == "derive" {
 560                                                 for id in g.stream().into_iter() {
 561                                                         if let TokenTree::Ident(i) = id {
 562                                                                 if i == "Clone" {
 563                                                                         writeln!(w, "impl Clone for {} {{", struct_name).unwrap();
 564                                                                         writeln!(w, "\tfn clone(&self) -> Self {{").unwrap();
 565                                                                         writeln!(w, "\t\tSelf {{").unwrap();
 566                                                                         writeln!(w, "\t\t\tinner: Box::into_raw(Box::new(unsafe {{ &*self.inner }}.clone())),").unwrap();
 567                                                                         writeln!(w, "\t\t\tis_owned: true,").unwrap();
 568                                                                         writeln!(w, "\t\t}}\n\t}}\n}}").unwrap();
 569                                                                         writeln!(w, "#[allow(unused)]").unwrap();
 570                                                                         writeln!(w, "/// Used only if an object of this type is returned as a trait impl by a method").unwrap();
 571                                                                         writeln!(w, "pub(crate) extern \"C\" fn {}_clone_void(this_ptr: *const c_void) -> *mut c_void {{", struct_name).unwrap();
 572                                                                         writeln!(w, "\tBox::into_raw(Box::new(unsafe {{ (*(this_ptr as *mut native{})).clone() }})) as *mut c_void", struct_name).unwrap();
 573                                                                         writeln!(w, "}}").unwrap();
 574                                                                         writeln!(w, "#[no_mangle]").unwrap();
 575                                                                         writeln!(w, "pub extern \"C\" fn {}_clone(orig: &{}) -> {} {{", struct_name, struct_name, struct_name).unwrap();
 576                                                                         writeln!(w, "\t{} {{ inner: Box::into_raw(Box::new(unsafe {{ &*orig.inner }}.clone())), is_owned: true }}", struct_name).unwrap();
 577                                                                         writeln!(w, "}}").unwrap();
 578                                                                         break 'attr_loop;
 579                                                                 }
 580                                                         }
 581                                                 }
 582                                         }
 583                                 },
 584                                 _ => {},
 585                         }
 586                 }
 587         }
 588
 589         write_cpp_wrapper(cpp_headers, &format!("{}", ident), true);
 590 }
 591
 592 fn declare_struct<'a, 'b>(s: &'a syn::ItemStruct, types: &mut TypeResolver<'b, 'a>) -> bool {
 593         let export = export_status(&s.attrs);
 594         match export {
 595                 ExportStatus::Export => {},
 596                 ExportStatus::TestOnly => return false,
 597                 ExportStatus::NoExport => {
 598                         types.struct_ignored(&s.ident);
 599                         return false;
 600                 }
 601         }
 602
 603         types.struct_imported(&s.ident, format!("{}", s.ident));
 604         true
 605 }
 606
 607 /// Writes out all the relevant mappings for a Rust struct, deferring to writeln_opaque to generate
 608 /// the struct itself, and then writing getters and setters for public, understood-type fields and
 609 /// a constructor if every field is public.
 610 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) {
 611         if !declare_struct(s, types) { return; }
 612
 613         let struct_name = &format!("{}", s.ident);
 614         writeln_opaque(w, &s.ident, struct_name, &s.generics, &s.attrs, types, extra_headers, cpp_headers);
 615
 616         eprintln!("exporting fields for {}", struct_name);
 617         if let syn::Fields::Named(fields) = &s.fields {
 618                 let mut gen_types = GenericTypes::new();
 619                 assert!(gen_types.learn_generics(&s.generics, types));
 620
 621                 let mut all_fields_settable = true;
 622                 for field in fields.named.iter() {
 623                         if let syn::Visibility::Public(_) = field.vis {
 624                                 let export = export_status(&field.attrs);
 625                                 match export {
 626                                         ExportStatus::Export => {},
 627                                         ExportStatus::NoExport|ExportStatus::TestOnly => {
 628                                                 all_fields_settable = false;
 629                                                 continue
 630                                         },
 631                                 }
 632
 633                                 if let Some(ident) = &field.ident {
 634                                         let ref_type = syn::Type::Reference(syn::TypeReference {
 635                                                 and_token: syn::Token!(&)(Span::call_site()), lifetime: None, mutability: None,
 636                                                 elem: Box::new(field.ty.clone()) });
 637                                         if types.understood_c_type(&ref_type, Some(&gen_types)) {
 638                                                 writeln_docs(w, &field.attrs, "");
 639                                                 write!(w, "#[no_mangle]\npub extern \"C\" fn {}_get_{}(this_ptr: &{}) -> ", struct_name, ident, struct_name).unwrap();
 640                                                 types.write_c_type(w, &ref_type, Some(&gen_types), true);
 641                                                 write!(w, " {{\n\tlet mut inner_val = &mut unsafe {{ &mut *this_ptr.inner }}.{};\n\t", ident).unwrap();
 642                                                 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);
 643                                                 if local_var { write!(w, "\n\t").unwrap(); }
 644                                                 types.write_to_c_conversion_inline_prefix(w, &ref_type, Some(&gen_types), true);
 645                                                 if local_var {
 646                                                         write!(w, "inner_val").unwrap();
 647                                                 } else {
 648                                                         write!(w, "(*inner_val)").unwrap();
 649                                                 }
 650                                                 types.write_to_c_conversion_inline_suffix(w, &ref_type, Some(&gen_types), true);
 651                                                 writeln!(w, "\n}}").unwrap();
 652                                         }
 653
 654                                         if types.understood_c_type(&field.ty, Some(&gen_types)) {
 655                                                 writeln_docs(w, &field.attrs, "");
 656                                                 write!(w, "#[no_mangle]\npub extern \"C\" fn {}_set_{}(this_ptr: &mut {}, mut val: ", struct_name, ident, struct_name).unwrap();
 657                                                 types.write_c_type(w, &field.ty, Some(&gen_types), false);
 658                                                 write!(w, ") {{\n\t").unwrap();
 659                                                 let local_var = types.write_from_c_conversion_new_var(w, &syn::Ident::new("val", Span::call_site()), &field.ty, Some(&gen_types));
 660                                                 if local_var { write!(w, "\n\t").unwrap(); }
 661                                                 write!(w, "unsafe {{ &mut *this_ptr.inner }}.{} = ", ident).unwrap();
 662                                                 types.write_from_c_conversion_prefix(w, &field.ty, Some(&gen_types));
 663                                                 write!(w, "val").unwrap();
 664                                                 types.write_from_c_conversion_suffix(w, &field.ty, Some(&gen_types));
 665                                                 writeln!(w, ";\n}}").unwrap();
 666                                         } else { all_fields_settable = false; }
 667                                 } else { all_fields_settable = false; }
 668                         } else { all_fields_settable = false; }
 669                 }
 670
 671                 if all_fields_settable {
 672                         // Build a constructor!
 673                         write!(w, "#[must_use]\n#[no_mangle]\npub extern \"C\" fn {}_new(", struct_name).unwrap();
 674                         for (idx, field) in fields.named.iter().enumerate() {
 675                                 if idx != 0 { write!(w, ", ").unwrap(); }
 676                                 write!(w, "mut {}_arg: ", field.ident.as_ref().unwrap()).unwrap();
 677                                 types.write_c_type(w, &field.ty, Some(&gen_types), false);
 678                         }
 679                         write!(w, ") -> {} {{\n\t", struct_name).unwrap();
 680                         for field in fields.named.iter() {
 681                                 let field_name = format!("{}_arg", field.ident.as_ref().unwrap());
 682                                 if types.write_from_c_conversion_new_var(w, &syn::Ident::new(&field_name, Span::call_site()), &field.ty, Some(&gen_types)) {
 683                                         write!(w, "\n\t").unwrap();
 684                                 }
 685                         }
 686                         writeln!(w, "{} {{ inner: Box::into_raw(Box::new(native{} {{", struct_name, s.ident).unwrap();
 687                         for field in fields.named.iter() {
 688                                 write!(w, "\t\t{}: ", field.ident.as_ref().unwrap()).unwrap();
 689                                 types.write_from_c_conversion_prefix(w, &field.ty, Some(&gen_types));
 690                                 write!(w, "{}_arg", field.ident.as_ref().unwrap()).unwrap();
 691                                 types.write_from_c_conversion_suffix(w, &field.ty, Some(&gen_types));
 692                                 writeln!(w, ",").unwrap();
 693                         }
 694                         writeln!(w, "\t}})), is_owned: true }}\n}}").unwrap();
 695                 }
 696         }
 697 }
 698
 699 /// Prints a relevant conversion for impl *
 700 ///
 701 /// For simple impl Struct {}s, this just outputs the wrapper functions as Struct_fn_name() { .. }.
 702 ///
 703 /// For impl Trait for Struct{}s, this non-exported generates wrapper functions as
 704 /// Trait_Struct_fn_name and a Struct_as_Trait(&struct) -> Trait function which returns a populated
 705 /// Trait struct containing a pointer to the passed struct's inner field and the wrapper functions.
 706 ///
 707 /// A few non-crate Traits are hard-coded including Default.
 708 fn writeln_impl<W: std::io::Write>(w: &mut W, i: &syn::ItemImpl, types: &mut TypeResolver) {
 709         match export_status(&i.attrs) {
 710                 ExportStatus::Export => {},
 711                 ExportStatus::NoExport|ExportStatus::TestOnly => return,
 712         }
 713
 714         if let syn::Type::Tuple(_) = &*i.self_ty {
 715                 if types.understood_c_type(&*i.self_ty, None) {
 716                         let mut gen_types = GenericTypes::new();
 717                         if !gen_types.learn_generics(&i.generics, types) {
 718                                 eprintln!("Not implementing anything for impl tuple due to not understood generics");
 719                                 return;
 720                         }
 721
 722                         if i.defaultness.is_some() || i.unsafety.is_some() { unimplemented!(); }
 723                         if let Some(trait_path) = i.trait_.as_ref() {
 724                                 if trait_path.0.is_some() { unimplemented!(); }
 725                                 if types.understood_c_path(&trait_path.1) {
 726                                         eprintln!("Not implementing anything for impl Trait for Tuple - we only support manual defines");
 727                                         return;
 728                                 } else {
 729                                         // Just do a manual implementation:
 730                                         maybe_convert_trait_impl(w, &trait_path.1, &*i.self_ty, types, &gen_types);
 731                                 }
 732                         } else {
 733                                 eprintln!("Not implementing anything for plain impl tuple block - we only support impl Trait for Tuples");
 734                                 return;
 735                         }
 736                 }
 737         }
 738         if let &syn::Type::Path(ref p) = &*i.self_ty {
 739                 if p.qself.is_some() { unimplemented!(); }
 740                 if let Some(ident) = single_ident_generic_path_to_ident(&p.path) {
 741                         if let Some(resolved_path) = types.maybe_resolve_non_ignored_ident(&ident) {
 742                                 let mut gen_types = GenericTypes::new();
 743                                 if !gen_types.learn_generics(&i.generics, types) {
 744                                         eprintln!("Not implementing anything for impl {} due to not understood generics", ident);
 745                                         return;
 746                                 }
 747
 748                                 if i.defaultness.is_some() || i.unsafety.is_some() { unimplemented!(); }
 749                                 if let Some(trait_path) = i.trait_.as_ref() {
 750                                         if trait_path.0.is_some() { unimplemented!(); }
 751                                         if types.understood_c_path(&trait_path.1) {
 752                                                 let full_trait_path = types.resolve_path(&trait_path.1, None);
 753                                                 let trait_obj = *types.crate_types.traits.get(&full_trait_path).unwrap();
 754                                                 // We learn the associated types maping from the original trait object.
 755                                                 // That's great, except that they are unresolved idents, so if we learn
 756                                                 // mappings from a trai defined in a different file, we may mis-resolve or
 757                                                 // fail to resolve the mapped types.
 758                                                 gen_types.learn_associated_types(trait_obj, types);
 759                                                 let mut impl_associated_types = HashMap::new();
 760                                                 for item in i.items.iter() {
 761                                                         match item {
 762                                                                 syn::ImplItem::Type(t) => {
 763                                                                         if let syn::Type::Path(p) = &t.ty {
 764                                                                                 if let Some(id) = single_ident_generic_path_to_ident(&p.path) {
 765                                                                                         impl_associated_types.insert(&t.ident, id);
 766                                                                                 }
 767                                                                         }
 768                                                                 },
 769                                                                 _ => {},
 770                                                         }
 771                                                 }
 772
 773                                                 let export = export_status(&trait_obj.attrs);
 774                                                 match export {
 775                                                         ExportStatus::Export => {},
 776                                                         ExportStatus::NoExport|ExportStatus::TestOnly => return,
 777                                                 }
 778
 779                                                 // For cases where we have a concrete native object which implements a
 780                                                 // trait and need to return the C-mapped version of the trait, provide a
 781                                                 // From<> implementation which does all the work to ensure free is handled
 782                                                 // properly. This way we can call this method from deep in the
 783                                                 // type-conversion logic without actually knowing the concrete native type.
 784                                                 writeln!(w, "impl From<native{}> for crate::{} {{", ident, full_trait_path).unwrap();
 785                                                 writeln!(w, "\tfn from(obj: native{}) -> Self {{", ident).unwrap();
 786                                                 writeln!(w, "\t\tlet mut rust_obj = {} {{ inner: Box::into_raw(Box::new(obj)), is_owned: true }};", ident).unwrap();
 787                                                 writeln!(w, "\t\tlet mut ret = {}_as_{}(&rust_obj);", ident, trait_obj.ident).unwrap();
 788                                                 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();
 789                                                 writeln!(w, "\t\trust_obj.inner = std::ptr::null_mut();").unwrap();
 790                                                 writeln!(w, "\t\tret.free = Some({}_free_void);", ident).unwrap();
 791                                                 writeln!(w, "\t\tret\n\t}}\n}}").unwrap();
 792
 793                                                 write!(w, "#[no_mangle]\npub extern \"C\" fn {}_as_{}(this_arg: *const {}) -> crate::{} {{\n", ident, trait_obj.ident, ident, full_trait_path).unwrap();
 794                                                 writeln!(w, "\tcrate::{} {{", full_trait_path).unwrap();
 795                                                 writeln!(w, "\t\tthis_arg: unsafe {{ (*this_arg).inner as *mut c_void }},").unwrap();
 796                                                 writeln!(w, "\t\tfree: None,").unwrap();
 797
 798                                                 macro_rules! write_meth {
 799                                                         ($m: expr, $trait: expr, $indent: expr) => {
 800                                                                 let trait_method = $trait.items.iter().filter_map(|item| {
 801                                                                         if let syn::TraitItem::Method(t_m) = item { Some(t_m) } else { None }
 802                                                                 }).find(|trait_meth| trait_meth.sig.ident == $m.sig.ident).unwrap();
 803                                                                 match export_status(&trait_method.attrs) {
 804                                                                         ExportStatus::Export => {},
 805                                                                         ExportStatus::NoExport => {
 806                                                                                 write!(w, "{}\t\t//XXX: Need to export {}\n", $indent, $m.sig.ident).unwrap();
 807                                                                                 continue;
 808                                                                         },
 809                                                                         ExportStatus::TestOnly => continue,
 810                                                                 }
 811
 812                                                                 let mut printed = false;
 813                                                                 if let syn::ReturnType::Type(_, rtype) = &$m.sig.output {
 814                                                                         if let syn::Type::Reference(r) = &**rtype {
 815                                                                                 write!(w, "\n\t\t{}{}: ", $indent, $m.sig.ident).unwrap();
 816                                                                                 types.write_empty_rust_val(Some(&gen_types), w, &*r.elem);
 817                                                                                 writeln!(w, ",\n{}\t\tset_{}: Some({}_{}_set_{}),", $indent, $m.sig.ident, ident, trait_obj.ident, $m.sig.ident).unwrap();
 818                                                                                 printed = true;
 819                                                                         }
 820                                                                 }
 821                                                                 if !printed {
 822                                                                         write!(w, "{}\t\t{}: {}_{}_{},\n", $indent, $m.sig.ident, ident, trait_obj.ident, $m.sig.ident).unwrap();
 823                                                                 }
 824                                                         }
 825                                                 }
 826                                                 for item in trait_obj.items.iter() {
 827                                                         match item {
 828                                                                 syn::TraitItem::Method(m) => {
 829                                                                         write_meth!(m, trait_obj, "");
 830                                                                 },
 831                                                                 _ => {},
 832                                                         }
 833                                                 }
 834                                                 walk_supertraits!(trait_obj, types, (
 835                                                         ("Clone", _) => {
 836                                                                 writeln!(w, "\t\tclone: Some({}_clone_void),", ident).unwrap();
 837                                                         },
 838                                                         ("Sync", _) => {}, ("Send", _) => {},
 839                                                         ("std::marker::Sync", _) => {}, ("std::marker::Send", _) => {},
 840                                                         (s, t) => {
 841                                                                 if let Some(supertrait_obj) = types.crate_types.traits.get(s) {
 842                                                                         writeln!(w, "\t\t{}: crate::{} {{", t, s).unwrap();
 843                                                                         writeln!(w, "\t\t\tthis_arg: unsafe {{ (*this_arg).inner as *mut c_void }},").unwrap();
 844                                                                         writeln!(w, "\t\t\tfree: None,").unwrap();
 845                                                                         for item in supertrait_obj.items.iter() {
 846                                                                                 match item {
 847                                                                                         syn::TraitItem::Method(m) => {
 848                                                                                                 write_meth!(m, supertrait_obj, "\t");
 849                                                                                         },
 850                                                                                         _ => {},
 851                                                                                 }
 852                                                                         }
 853                                                                         write!(w, "\t\t}},\n").unwrap();
 854                                                                 } else {
 855                                                                         write_trait_impl_field_assign(w, s, ident);
 856                                                                 }
 857                                                         }
 858                                                 ) );
 859                                                 write!(w, "\t}}\n}}\nuse {}::{} as {}TraitImport;\n", types.orig_crate, full_trait_path, trait_obj.ident).unwrap();
 860
 861                                                 macro_rules! impl_meth {
 862                                                         ($m: expr, $trait: expr, $indent: expr) => {
 863                                                                 let trait_method = $trait.items.iter().filter_map(|item| {
 864                                                                         if let syn::TraitItem::Method(t_m) = item { Some(t_m) } else { None }
 865                                                                 }).find(|trait_meth| trait_meth.sig.ident == $m.sig.ident).unwrap();
 866                                                                 match export_status(&trait_method.attrs) {
 867                                                                         ExportStatus::Export => {},
 868                                                                         ExportStatus::NoExport|ExportStatus::TestOnly => continue,
 869                                                                 }
 870
 871                                                                 if let syn::ReturnType::Type(_, _) = &$m.sig.output {
 872                                                                         writeln!(w, "#[must_use]").unwrap();
 873                                                                 }
 874                                                                 write!(w, "extern \"C\" fn {}_{}_{}(", ident, trait_obj.ident, $m.sig.ident).unwrap();
 875                                                                 gen_types.push_ctx();
 876                                                                 assert!(gen_types.learn_generics(&$m.sig.generics, types));
 877                                                                 write_method_params(w, &$m.sig, "c_void", types, Some(&gen_types), true, true);
 878                                                                 write!(w, " {{\n\t").unwrap();
 879                                                                 write_method_var_decl_body(w, &$m.sig, "", types, Some(&gen_types), false);
 880                                                                 let mut takes_self = false;
 881                                                                 for inp in $m.sig.inputs.iter() {
 882                                                                         if let syn::FnArg::Receiver(_) = inp {
 883                                                                                 takes_self = true;
 884                                                                         }
 885                                                                 }
 886                                                                 if takes_self {
 887                                                                         write!(w, "unsafe {{ &mut *(this_arg as *mut native{}) }}.{}(", ident, $m.sig.ident).unwrap();
 888                                                                 } else {
 889                                                                         write!(w, "{}::{}::{}(", types.orig_crate, resolved_path, $m.sig.ident).unwrap();
 890                                                                 }
 891
 892                                                                 let mut real_type = "".to_string();
 893                                                                 match &$m.sig.output {
 894                                                                         syn::ReturnType::Type(_, rtype) => {
 895                                                                                 if let Some(mut remaining_path) = first_seg_self(&*rtype) {
 896                                                                                         if let Some(associated_seg) = get_single_remaining_path_seg(&mut remaining_path) {
 897                                                                                                 real_type = format!("{}", impl_associated_types.get(associated_seg).unwrap());
 898                                                                                         }
 899                                                                                 }
 900                                                                         },
 901                                                                         _ => {},
 902                                                                 }
 903                                                                 write_method_call_params(w, &$m.sig, "", types, Some(&gen_types), &real_type, false);
 904                                                                 gen_types.pop_ctx();
 905                                                                 write!(w, "\n}}\n").unwrap();
 906                                                                 if let syn::ReturnType::Type(_, rtype) = &$m.sig.output {
 907                                                                         if let syn::Type::Reference(r) = &**rtype {
 908                                                                                 assert_eq!($m.sig.inputs.len(), 1); // Must only take self
 909                                                                                 writeln!(w, "extern \"C\" fn {}_{}_set_{}(trait_self_arg: &{}) {{", ident, trait_obj.ident, $m.sig.ident, trait_obj.ident).unwrap();
 910                                                                                 writeln!(w, "\t// This is a bit race-y in the general case, but for our specific use-cases today, we're safe").unwrap();
 911                                                                                 writeln!(w, "\t// Specifically, we must ensure that the first time we're called it can never be in parallel").unwrap();
 912                                                                                 write!(w, "\tif ").unwrap();
 913                                                                                 types.write_empty_rust_val_check(Some(&gen_types), w, &*r.elem, &format!("trait_self_arg.{}", $m.sig.ident));
 914                                                                                 writeln!(w, " {{").unwrap();
 915                                                                                 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();
 916                                                                                 writeln!(w, "\t}}").unwrap();
 917                                                                                 writeln!(w, "}}").unwrap();
 918                                                                         }
 919                                                                 }
 920                                                         }
 921                                                 }
 922
 923                                                 for item in i.items.iter() {
 924                                                         match item {
 925                                                                 syn::ImplItem::Method(m) => {
 926                                                                         impl_meth!(m, trait_obj, "");
 927                                                                 },
 928                                                                 syn::ImplItem::Type(_) => {},
 929                                                                 _ => unimplemented!(),
 930                                                         }
 931                                                 }
 932                                                 walk_supertraits!(trait_obj, types, (
 933                                                         (s, t) => {
 934                                                                 if let Some(supertrait_obj) = types.crate_types.traits.get(s).cloned() {
 935                                                                         writeln!(w, "use {}::{} as native{}Trait;", types.orig_crate, s, t).unwrap();
 936                                                                         for item in supertrait_obj.items.iter() {
 937                                                                                 match item {
 938                                                                                         syn::TraitItem::Method(m) => {
 939                                                                                                 impl_meth!(m, supertrait_obj, "\t");
 940                                                                                         },
 941                                                                                         _ => {},
 942                                                                                 }
 943                                                                         }
 944                                                                 }
 945                                                         }
 946                                                 ) );
 947                                                 write!(w, "\n").unwrap();
 948                                         } else if let Some(trait_ident) = trait_path.1.get_ident() {
 949                                                 //XXX: implement for other things like ToString
 950                                                 match &format!("{}", trait_ident) as &str {
 951                                                         "From" => {},
 952                                                         "Default" => {
 953                                                                 write!(w, "#[must_use]\n#[no_mangle]\npub extern \"C\" fn {}_default() -> {} {{\n", ident, ident).unwrap();
 954                                                                 write!(w, "\t{} {{ inner: Box::into_raw(Box::new(Default::default())), is_owned: true }}\n", ident).unwrap();
 955                                                                 write!(w, "}}\n").unwrap();
 956                                                         },
 957                                                         "PartialEq" => {},
 958                                                         // If we have no generics, try a manual implementation:
 959                                                         _ => maybe_convert_trait_impl(w, &trait_path.1, &*i.self_ty, types, &gen_types),
 960                                                 }
 961                                         } else {
 962                                                 // If we have no generics, try a manual implementation:
 963                                                 maybe_convert_trait_impl(w, &trait_path.1, &*i.self_ty, types, &gen_types);
 964                                         }
 965                                 } else {
 966                                         let declared_type = (*types.get_declared_type(&ident).unwrap()).clone();
 967                                         for item in i.items.iter() {
 968                                                 match item {
 969                                                         syn::ImplItem::Method(m) => {
 970                                                                 if let syn::Visibility::Public(_) = m.vis {
 971                                                                         match export_status(&m.attrs) {
 972                                                                                 ExportStatus::Export => {},
 973                                                                                 ExportStatus::NoExport|ExportStatus::TestOnly => continue,
 974                                                                         }
 975                                                                         if m.defaultness.is_some() { unimplemented!(); }
 976                                                                         writeln_docs(w, &m.attrs, "");
 977                                                                         if let syn::ReturnType::Type(_, _) = &m.sig.output {
 978                                                                                 writeln!(w, "#[must_use]").unwrap();
 979                                                                         }
 980                                                                         write!(w, "#[no_mangle]\npub extern \"C\" fn {}_{}(", ident, m.sig.ident).unwrap();
 981                                                                         let ret_type = match &declared_type {
 982                                                                                 DeclType::MirroredEnum => format!("{}", ident),
 983                                                                                 DeclType::StructImported => format!("{}", ident),
 984                                                                                 _ => unimplemented!(),
 985                                                                         };
 986                                                                         gen_types.push_ctx();
 987                                                                         assert!(gen_types.learn_generics(&m.sig.generics, types));
 988                                                                         write_method_params(w, &m.sig, &ret_type, types, Some(&gen_types), false, true);
 989                                                                         write!(w, " {{\n\t").unwrap();
 990                                                                         write_method_var_decl_body(w, &m.sig, "", types, Some(&gen_types), false);
 991                                                                         let mut takes_self = false;
 992                                                                         let mut takes_mut_self = false;
 993                                                                         for inp in m.sig.inputs.iter() {
 994                                                                                 if let syn::FnArg::Receiver(r) = inp {
 995                                                                                         takes_self = true;
 996                                                                                         if r.mutability.is_some() { takes_mut_self = true; }
 997                                                                                 }
 998                                                                         }
 999                                                                         if takes_mut_self {
1000                                                                                 write!(w, "unsafe {{ &mut (*(this_arg.inner as *mut native{})) }}.{}(", ident, m.sig.ident).unwrap();
1001                                                                         } else if takes_self {
1002                                                                                 write!(w, "unsafe {{ &*this_arg.inner }}.{}(", m.sig.ident).unwrap();
1003                                                                         } else {
1004                                                                                 write!(w, "{}::{}::{}(", types.orig_crate, resolved_path, m.sig.ident).unwrap();
1005                                                                         }
1006                                                                         write_method_call_params(w, &m.sig, "", types, Some(&gen_types), &ret_type, false);
1007                                                                         gen_types.pop_ctx();
1008                                                                         writeln!(w, "\n}}\n").unwrap();
1009                                                                 }
1010                                                         },
1011                                                         _ => {},
1012                                                 }
1013                                         }
1014                                 }
1015                         } else {
1016                                 eprintln!("Not implementing anything for {} due to no-resolve (probably the type isn't pub or its marked not exported)", ident);
1017                         }
1018                 }
1019         }
1020 }
1021
1022 /// Returns true if the enum will be mapped as an opaue (ie struct with a pointer to the underlying
1023 /// type), otherwise it is mapped into a transparent, C-compatible version of itself.
1024 fn is_enum_opaque(e: &syn::ItemEnum) -> bool {
1025         for var in e.variants.iter() {
1026                 if let syn::Fields::Unit = var.fields {
1027                 } else if let syn::Fields::Named(fields) = &var.fields {
1028                         for field in fields.named.iter() {
1029                                 match export_status(&field.attrs) {
1030                                         ExportStatus::Export|ExportStatus::TestOnly => {},
1031                                         ExportStatus::NoExport => return true,
1032                                 }
1033                         }
1034                 } else {
1035                         return true;
1036                 }
1037         }
1038         false
1039 }
1040
1041 fn declare_enum<'a, 'b>(e: &'a syn::ItemEnum, types: &mut TypeResolver<'b, 'a>) {
1042         match export_status(&e.attrs) {
1043                 ExportStatus::Export => {},
1044                 ExportStatus::NoExport|ExportStatus::TestOnly => return,
1045         }
1046
1047         if is_enum_opaque(e) {
1048                 types.enum_ignored(&e.ident);
1049         } else {
1050                 types.mirrored_enum_declared(&e.ident);
1051         }
1052 }
1053
1054 /// Print a mapping of an enum. If all of the enum's fields are C-mapped in some form (or the enum
1055 /// is unitary), we generate an equivalent enum with all types replaced with their C mapped
1056 /// versions followed by conversion functions which map between the Rust version and the C mapped
1057 /// version.
1058 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) {
1059         match export_status(&e.attrs) {
1060                 ExportStatus::Export => {},
1061                 ExportStatus::NoExport|ExportStatus::TestOnly => return,
1062         }
1063
1064         if is_enum_opaque(e) {
1065                 eprintln!("Skipping enum {} as it contains non-unit fields", e.ident);
1066                 writeln_opaque(w, &e.ident, &format!("{}", e.ident), &e.generics, &e.attrs, types, extra_headers, cpp_headers);
1067                 return;
1068         }
1069         writeln_docs(w, &e.attrs, "");
1070
1071         if e.generics.lt_token.is_some() {
1072                 unimplemented!();
1073         }
1074
1075         let mut needs_free = false;
1076
1077         writeln!(w, "#[must_use]\n#[derive(Clone)]\n#[repr(C)]\npub enum {} {{", e.ident).unwrap();
1078         for var in e.variants.iter() {
1079                 assert_eq!(export_status(&var.attrs), ExportStatus::Export); // We can't partially-export a mirrored enum
1080                 writeln_docs(w, &var.attrs, "\t");
1081                 write!(w, "\t{}", var.ident).unwrap();
1082                 if let syn::Fields::Named(fields) = &var.fields {
1083                         needs_free = true;
1084                         writeln!(w, " {{").unwrap();
1085                         for field in fields.named.iter() {
1086                                 if export_status(&field.attrs) == ExportStatus::TestOnly { continue; }
1087                                 write!(w, "\t\t{}: ", field.ident.as_ref().unwrap()).unwrap();
1088                                 types.write_c_type(w, &field.ty, None, false);
1089                                 writeln!(w, ",").unwrap();
1090                         }
1091                         write!(w, "\t}}").unwrap();
1092                 }
1093                 if var.discriminant.is_some() { unimplemented!(); }
1094                 writeln!(w, ",").unwrap();
1095         }
1096         writeln!(w, "}}\nuse {}::{}::{} as native{};\nimpl {} {{", types.orig_crate, types.module_path, e.ident, e.ident, e.ident).unwrap();
1097
1098         macro_rules! write_conv {
1099                 ($fn_sig: expr, $to_c: expr, $ref: expr) => {
1100                         writeln!(w, "\t#[allow(unused)]\n\tpub(crate) fn {} {{\n\t\tmatch {} {{", $fn_sig, if $to_c { "native" } else { "self" }).unwrap();
1101                         for var in e.variants.iter() {
1102                                 write!(w, "\t\t\t{}{}::{} ", if $to_c { "native" } else { "" }, e.ident, var.ident).unwrap();
1103                                 if let syn::Fields::Named(fields) = &var.fields {
1104                                         write!(w, "{{").unwrap();
1105                                         for field in fields.named.iter() {
1106                                                 if export_status(&field.attrs) == ExportStatus::TestOnly { continue; }
1107                                                 write!(w, "{}{}, ", if $ref { "ref " } else { "mut " }, field.ident.as_ref().unwrap()).unwrap();
1108                                         }
1109                                         write!(w, "}} ").unwrap();
1110                                 }
1111                                 write!(w, "=>").unwrap();
1112                                 if let syn::Fields::Named(fields) = &var.fields {
1113                                         write!(w, " {{\n\t\t\t\t").unwrap();
1114                                         for field in fields.named.iter() {
1115                                                 if export_status(&field.attrs) == ExportStatus::TestOnly { continue; }
1116                                                 let mut sink = ::std::io::sink();
1117                                                 let mut out: &mut dyn std::io::Write = if $ref { &mut sink } else { w };
1118                                                 let new_var = if $to_c {
1119                                                         types.write_to_c_conversion_new_var(&mut out, field.ident.as_ref().unwrap(), &field.ty, None, false)
1120                                                 } else {
1121                                                         types.write_from_c_conversion_new_var(&mut out, field.ident.as_ref().unwrap(), &field.ty, None)
1122                                                 };
1123                                                 if $ref || new_var {
1124                                                         if $ref {
1125                                                                 write!(w, "let mut {}_nonref = (*{}).clone();\n\t\t\t\t", field.ident.as_ref().unwrap(), field.ident.as_ref().unwrap()).unwrap();
1126                                                                 if new_var {
1127                                                                         let nonref_ident = syn::Ident::new(&format!("{}_nonref", field.ident.as_ref().unwrap()), Span::call_site());
1128                                                                         if $to_c {
1129                                                                                 types.write_to_c_conversion_new_var(w, &nonref_ident, &field.ty, None, false);
1130                                                                         } else {
1131                                                                                 types.write_from_c_conversion_new_var(w, &nonref_ident, &field.ty, None);
1132                                                                         }
1133                                                                         write!(w, "\n\t\t\t\t").unwrap();
1134                                                                 }
1135                                                         } else {
1136                                                                 write!(w, "\n\t\t\t\t").unwrap();
1137                                                         }
1138                                                 }
1139                                         }
1140                                 } else { write!(w, " ").unwrap(); }
1141                                 write!(w, "{}{}::{}", if $to_c { "" } else { "native" }, e.ident, var.ident).unwrap();
1142                                 if let syn::Fields::Named(fields) = &var.fields {
1143                                         write!(w, " {{").unwrap();
1144                                         for field in fields.named.iter() {
1145                                                 if export_status(&field.attrs) == ExportStatus::TestOnly { continue; }
1146                                                 write!(w, "\n\t\t\t\t\t{}: ", field.ident.as_ref().unwrap()).unwrap();
1147                                                 if $to_c {
1148                                                         types.write_to_c_conversion_inline_prefix(w, &field.ty, None, false);
1149                                                 } else {
1150                                                         types.write_from_c_conversion_prefix(w, &field.ty, None);
1151                                                 }
1152                                                 write!(w, "{}{}",
1153                                                         field.ident.as_ref().unwrap(),
1154                                                         if $ref { "_nonref" } else { "" }).unwrap();
1155                                                 if $to_c {
1156                                                         types.write_to_c_conversion_inline_suffix(w, &field.ty, None, false);
1157                                                 } else {
1158                                                         types.write_from_c_conversion_suffix(w, &field.ty, None);
1159                                                 }
1160                                                 write!(w, ",").unwrap();
1161                                         }
1162                                         writeln!(w, "\n\t\t\t\t}}").unwrap();
1163                                         write!(w, "\t\t\t}}").unwrap();
1164                                 }
1165                                 writeln!(w, ",").unwrap();
1166                         }
1167                         writeln!(w, "\t\t}}\n\t}}").unwrap();
1168                 }
1169         }
1170
1171         write_conv!(format!("to_native(&self) -> native{}", e.ident), false, true);
1172         write_conv!(format!("into_native(self) -> native{}", e.ident), false, false);
1173         write_conv!(format!("from_native(native: &native{}) -> Self", e.ident), true, true);
1174         write_conv!(format!("native_into(native: native{}) -> Self", e.ident), true, false);
1175         writeln!(w, "}}").unwrap();
1176
1177         if needs_free {
1178                 writeln!(w, "#[no_mangle]\npub extern \"C\" fn {}_free(this_ptr: {}) {{ }}", e.ident, e.ident).unwrap();
1179         }
1180         writeln!(w, "#[no_mangle]").unwrap();
1181         writeln!(w, "pub extern \"C\" fn {}_clone(orig: &{}) -> {} {{", e.ident, e.ident, e.ident).unwrap();
1182         writeln!(w, "\torig.clone()").unwrap();
1183         writeln!(w, "}}").unwrap();
1184         write_cpp_wrapper(cpp_headers, &format!("{}", e.ident), needs_free);
1185 }
1186
1187 fn writeln_fn<'a, 'b, W: std::io::Write>(w: &mut W, f: &'a syn::ItemFn, types: &mut TypeResolver<'b, 'a>) {
1188         match export_status(&f.attrs) {
1189                 ExportStatus::Export => {},
1190                 ExportStatus::NoExport|ExportStatus::TestOnly => return,
1191         }
1192         writeln_docs(w, &f.attrs, "");
1193
1194         let mut gen_types = GenericTypes::new();
1195         if !gen_types.learn_generics(&f.sig.generics, types) { return; }
1196
1197         write!(w, "#[no_mangle]\npub extern \"C\" fn {}(", f.sig.ident).unwrap();
1198         write_method_params(w, &f.sig, "", types, Some(&gen_types), false, true);
1199         write!(w, " {{\n\t").unwrap();
1200         write_method_var_decl_body(w, &f.sig, "", types, Some(&gen_types), false);
1201         write!(w, "{}::{}::{}(", types.orig_crate, types.module_path, f.sig.ident).unwrap();
1202         write_method_call_params(w, &f.sig, "", types, Some(&gen_types), "", false);
1203         writeln!(w, "\n}}\n").unwrap();
1204 }
1205
1206 // ********************************
1207 // *** File/Crate Walking Logic ***
1208 // ********************************
1209
1210 /// Simple utility to walk the modules in a crate - iterating over the modules (with file paths) in
1211 /// a single File.
1212 struct FileIter<'a, I: Iterator<Item = &'a syn::Item>> {
1213         in_dir: &'a str,
1214         path: &'a str,
1215         module: &'a str,
1216         item_iter: I,
1217 }
1218 impl<'a, I: Iterator<Item = &'a syn::Item>> Iterator for FileIter<'a, I> {
1219         type Item = (String, String, &'a syn::ItemMod);
1220         fn next(&mut self) -> std::option::Option<<Self as std::iter::Iterator>::Item> {
1221                 loop {
1222                         match self.item_iter.next() {
1223                                 Some(syn::Item::Mod(m)) => {
1224                                         if let syn::Visibility::Public(_) = m.vis {
1225                                                 match export_status(&m.attrs) {
1226                                                         ExportStatus::Export => {},
1227                                                         ExportStatus::NoExport|ExportStatus::TestOnly => continue,
1228                                                 }
1229
1230                                                 let f_path = format!("{}/{}.rs", (self.path.as_ref() as &Path).parent().unwrap().display(), m.ident);
1231                                                 let new_mod = if self.module.is_empty() { format!("{}", m.ident) } else { format!("{}::{}", self.module, m.ident) };
1232                                                 if let Ok(_) = File::open(&format!("{}/{}", self.in_dir, f_path)) {
1233                                                         return Some((f_path, new_mod, m));
1234                                                 } else {
1235                                                         return Some((
1236                                                                 format!("{}/{}/mod.rs", (self.path.as_ref() as &Path).parent().unwrap().display(), m.ident),
1237                                                                 new_mod, m));
1238                                                 }
1239                                         }
1240                                 },
1241                                 Some(_) => {},
1242                                 None => return None,
1243                         }
1244                 }
1245         }
1246 }
1247 fn file_iter<'a>(file: &'a syn::File, in_dir: &'a str, path: &'a str, module: &'a str) ->
1248                 impl Iterator<Item = (String, String, &'a syn::ItemMod)> + 'a {
1249         FileIter { in_dir, path, module, item_iter: file.items.iter() }
1250 }
1251
1252 /// A struct containing the syn::File AST for each file in the crate.
1253 struct FullLibraryAST {
1254         files: HashMap<String, syn::File>,
1255 }
1256
1257 /// Do the Real Work of mapping an original file to C-callable wrappers. Creates a new file at
1258 /// `out_path` and fills it with wrapper structs/functions to allow calling the things in the AST
1259 /// at `module` from C.
1260 fn convert_file<'a, 'b>(libast: &'a FullLibraryAST, crate_types: &mut CrateTypes<'a>, in_dir: &str, out_dir: &str, path: &str, orig_crate: &str, module: &str, header_file: &mut File, cpp_header_file: &mut File) {
1261         let syntax = if let Some(ast) = libast.files.get(module) { ast } else { return };
1262
1263         assert!(syntax.shebang.is_none()); // Not sure what this is, hope we dont have one
1264
1265         let new_file_path = format!("{}/{}", out_dir, path);
1266         let _ = std::fs::create_dir((&new_file_path.as_ref() as &std::path::Path).parent().unwrap());
1267         let mut out = std::fs::OpenOptions::new().write(true).create(true).truncate(true)
1268                 .open(new_file_path).expect("Unable to open new src file");
1269
1270         assert_eq!(export_status(&syntax.attrs), ExportStatus::Export);
1271         writeln_docs(&mut out, &syntax.attrs, "");
1272
1273         if path.ends_with("/lib.rs") {
1274                 // Special-case the top-level lib.rs with various lint allows and a pointer to the c_types
1275                 // and bitcoin hand-written modules.
1276                 writeln!(out, "#![allow(unknown_lints)]").unwrap();
1277                 writeln!(out, "#![allow(non_camel_case_types)]").unwrap();
1278                 writeln!(out, "#![allow(non_snake_case)]").unwrap();
1279                 writeln!(out, "#![allow(unused_imports)]").unwrap();
1280                 writeln!(out, "#![allow(unused_variables)]").unwrap();
1281                 writeln!(out, "#![allow(unused_mut)]").unwrap();
1282                 writeln!(out, "#![allow(unused_parens)]").unwrap();
1283                 writeln!(out, "#![allow(unused_unsafe)]").unwrap();
1284                 writeln!(out, "#![allow(unused_braces)]").unwrap();
1285                 writeln!(out, "mod c_types;").unwrap();
1286                 writeln!(out, "mod bitcoin;").unwrap();
1287         } else {
1288                 writeln!(out, "\nuse std::ffi::c_void;\nuse bitcoin::hashes::Hash;\nuse crate::c_types::*;\n").unwrap();
1289         }
1290
1291         for (path, new_mod, m) in file_iter(&syntax, in_dir, path, &module) {
1292                 writeln_docs(&mut out, &m.attrs, "");
1293                 writeln!(out, "pub mod {};", m.ident).unwrap();
1294                 convert_file(libast, crate_types, in_dir, out_dir, &path,
1295                         orig_crate, &new_mod, header_file, cpp_header_file);
1296         }
1297
1298         eprintln!("Converting {} entries...", path);
1299
1300         let mut type_resolver = TypeResolver::new(orig_crate, module, crate_types);
1301
1302         // First pass over the items and fill in imports and file-declared objects in the type resolver
1303         for item in syntax.items.iter() {
1304                 match item {
1305                         syn::Item::Use(u) => type_resolver.process_use(&mut out, &u),
1306                         syn::Item::Struct(s) => {
1307                                 if let syn::Visibility::Public(_) = s.vis {
1308                                         declare_struct(&s, &mut type_resolver);
1309                                 }
1310                         },
1311                         syn::Item::Enum(e) => {
1312                                 if let syn::Visibility::Public(_) = e.vis {
1313                                         declare_enum(&e, &mut type_resolver);
1314                                 }
1315                         },
1316                         _ => {},
1317                 }
1318         }
1319
1320         for item in syntax.items.iter() {
1321                 match item {
1322                         syn::Item::Use(_) => {}, // Handled above
1323                         syn::Item::Static(_) => {},
1324                         syn::Item::Enum(e) => {
1325                                 if let syn::Visibility::Public(_) = e.vis {
1326                                         writeln_enum(&mut out, &e, &mut type_resolver, header_file, cpp_header_file);
1327                                 }
1328                         },
1329                         syn::Item::Impl(i) => {
1330                                 writeln_impl(&mut out, &i, &mut type_resolver);
1331                         },
1332                         syn::Item::Struct(s) => {
1333                                 if let syn::Visibility::Public(_) = s.vis {
1334                                         writeln_struct(&mut out, &s, &mut type_resolver, header_file, cpp_header_file);
1335                                 }
1336                         },
1337                         syn::Item::Trait(t) => {
1338                                 if let syn::Visibility::Public(_) = t.vis {
1339                                         writeln_trait(&mut out, &t, &mut type_resolver, header_file, cpp_header_file);
1340                                 }
1341                         },
1342                         syn::Item::Mod(_) => {}, // We don't have to do anything - the top loop handles these.
1343                         syn::Item::Const(c) => {
1344                                 // Re-export any primitive-type constants.
1345                                 if let syn::Visibility::Public(_) = c.vis {
1346                                         if let syn::Type::Path(p) = &*c.ty {
1347                                                 let resolved_path = type_resolver.resolve_path(&p.path, None);
1348                                                 if type_resolver.is_primitive(&resolved_path) {
1349                                                         writeln!(out, "\n#[no_mangle]").unwrap();
1350                                                         writeln!(out, "pub static {}: {} = {}::{}::{};", c.ident, resolved_path, orig_crate, module, c.ident).unwrap();
1351                                                 }
1352                                         }
1353                                 }
1354                         },
1355                         syn::Item::Type(t) => {
1356                                 if let syn::Visibility::Public(_) = t.vis {
1357                                         match export_status(&t.attrs) {
1358                                                 ExportStatus::Export => {},
1359                                                 ExportStatus::NoExport|ExportStatus::TestOnly => continue,
1360                                         }
1361
1362                                         let mut process_alias = true;
1363                                         for tok in t.generics.params.iter() {
1364                                                 if let syn::GenericParam::Lifetime(_) = tok {}
1365                                                 else { process_alias = false; }
1366                                         }
1367                                         if process_alias {
1368                                                 match &*t.ty {
1369                                                         syn::Type::Path(_) =>
1370                                                                 writeln_opaque(&mut out, &t.ident, &format!("{}", t.ident), &t.generics, &t.attrs, &type_resolver, header_file, cpp_header_file),
1371                                                         _ => {}
1372                                                 }
1373                                         }
1374                                 }
1375                         },
1376                         syn::Item::Fn(f) => {
1377                                 if let syn::Visibility::Public(_) = f.vis {
1378                                         writeln_fn(&mut out, &f, &mut type_resolver);
1379                                 }
1380                         },
1381                         syn::Item::Macro(m) => {
1382                                 if m.ident.is_none() { // If its not a macro definition
1383                                         convert_macro(&mut out, &m.mac.path, &m.mac.tokens, &type_resolver);
1384                                 }
1385                         },
1386                         syn::Item::Verbatim(_) => {},
1387                         syn::Item::ExternCrate(_) => {},
1388                         _ => unimplemented!(),
1389                 }
1390         }
1391
1392         out.flush().unwrap();
1393 }
1394
1395 /// Load the AST for each file in the crate, filling the FullLibraryAST object
1396 fn load_ast(in_dir: &str, path: &str, module: String, ast_storage: &mut FullLibraryAST) {
1397         eprintln!("Loading {}{}...", in_dir, path);
1398
1399         let mut file = File::open(format!("{}/{}", in_dir, path)).expect("Unable to open file");
1400         let mut src = String::new();
1401         file.read_to_string(&mut src).expect("Unable to read file");
1402         let syntax = syn::parse_file(&src).expect("Unable to parse file");
1403
1404         assert_eq!(export_status(&syntax.attrs), ExportStatus::Export);
1405
1406         for (path, new_mod, _) in file_iter(&syntax, in_dir, path, &module) {
1407                 load_ast(in_dir, &path, new_mod, ast_storage);
1408         }
1409         ast_storage.files.insert(module, syntax);
1410 }
1411
1412 /// Insert ident -> absolute Path resolutions into imports from the given UseTree and path-prefix.
1413 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>) {
1414         match u {
1415                 syn::UseTree::Path(p) => {
1416                         path.push(syn::PathSegment { ident: p.ident.clone(), arguments: syn::PathArguments::None });
1417                         process_use_intern(&p.tree, path, imports);
1418                 },
1419                 syn::UseTree::Name(n) => {
1420                         path.push(syn::PathSegment { ident: n.ident.clone(), arguments: syn::PathArguments::None });
1421                         imports.insert(&n.ident, syn::Path { leading_colon: Some(syn::Token![::](Span::call_site())), segments: path });
1422                 },
1423                 syn::UseTree::Group(g) => {
1424                         for i in g.items.iter() {
1425                                 process_use_intern(i, path.clone(), imports);
1426                         }
1427                 },
1428                 _ => {}
1429         }
1430 }
1431
1432 /// Map all the Paths in a Type into absolute paths given a set of imports (generated via process_use_intern)
1433 fn resolve_imported_refs(imports: &HashMap<&syn::Ident, syn::Path>, mut ty: syn::Type) -> syn::Type {
1434         match &mut ty {
1435                 syn::Type::Path(p) => {
1436                         if let Some(ident) = p.path.get_ident() {
1437                                 if let Some(newpath) = imports.get(ident) {
1438                                         p.path = newpath.clone();
1439                                 }
1440                         } else { unimplemented!(); }
1441                 },
1442                 syn::Type::Reference(r) => {
1443                         r.elem = Box::new(resolve_imported_refs(imports, (*r.elem).clone()));
1444                 },
1445                 syn::Type::Slice(s) => {
1446                         s.elem = Box::new(resolve_imported_refs(imports, (*s.elem).clone()));
1447                 },
1448                 syn::Type::Tuple(t) => {
1449                         for e in t.elems.iter_mut() {
1450                                 *e = resolve_imported_refs(imports, e.clone());
1451                         }
1452                 },
1453                 _ => unimplemented!(),
1454         }
1455         ty
1456 }
1457
1458 /// Walk the FullLibraryAST, deciding how things will be mapped and adding tracking to CrateTypes.
1459 fn walk_ast<'a>(in_dir: &str, path: &str, module: String, ast_storage: &'a FullLibraryAST, crate_types: &mut CrateTypes<'a>) {
1460         let syntax = if let Some(ast) = ast_storage.files.get(&module) { ast } else { return };
1461         assert_eq!(export_status(&syntax.attrs), ExportStatus::Export);
1462
1463         for (path, new_mod, _) in file_iter(&syntax, in_dir, path, &module) {
1464                 walk_ast(in_dir, &path, new_mod, ast_storage, crate_types);
1465         }
1466
1467         let mut import_maps = HashMap::new();
1468
1469         for item in syntax.items.iter() {
1470                 match item {
1471                         syn::Item::Use(u) => {
1472                                 process_use_intern(&u.tree, syn::punctuated::Punctuated::new(), &mut import_maps);
1473                         },
1474                         syn::Item::Struct(s) => {
1475                                 if let syn::Visibility::Public(_) = s.vis {
1476                                         match export_status(&s.attrs) {
1477                                                 ExportStatus::Export => {},
1478                                                 ExportStatus::NoExport|ExportStatus::TestOnly => continue,
1479                                         }
1480                                         let struct_path = format!("{}::{}", module, s.ident);
1481                                         crate_types.opaques.insert(struct_path, &s.ident);
1482                                 }
1483                         },
1484                         syn::Item::Trait(t) => {
1485                                 if let syn::Visibility::Public(_) = t.vis {
1486                                         match export_status(&t.attrs) {
1487                                                 ExportStatus::Export => {},
1488                                                 ExportStatus::NoExport|ExportStatus::TestOnly => continue,
1489                                         }
1490                                         let trait_path = format!("{}::{}", module, t.ident);
1491                                         crate_types.traits.insert(trait_path, &t);
1492                                 }
1493                         },
1494                         syn::Item::Type(t) => {
1495                                 if let syn::Visibility::Public(_) = t.vis {
1496                                         match export_status(&t.attrs) {
1497                                                 ExportStatus::Export => {},
1498                                                 ExportStatus::NoExport|ExportStatus::TestOnly => continue,
1499                                         }
1500                                         let type_path = format!("{}::{}", module, t.ident);
1501                                         let mut process_alias = true;
1502                                         for tok in t.generics.params.iter() {
1503                                                 if let syn::GenericParam::Lifetime(_) = tok {}
1504                                                 else { process_alias = false; }
1505                                         }
1506                                         if process_alias {
1507                                                 match &*t.ty {
1508                                                         syn::Type::Path(_) => {
1509                                                                 // If its a path with no generics, assume we don't map the aliased type and map it opaque
1510                                                                 crate_types.opaques.insert(type_path, &t.ident);
1511                                                         },
1512                                                         _ => {
1513                                                                 crate_types.type_aliases.insert(type_path, resolve_imported_refs(&import_maps, (*t.ty).clone()));
1514                                                         }
1515                                                 }
1516                                         }
1517                                 }
1518                         },
1519                         syn::Item::Enum(e) if is_enum_opaque(e) => {
1520                                 if let syn::Visibility::Public(_) = e.vis {
1521                                         match export_status(&e.attrs) {
1522                                                 ExportStatus::Export => {},
1523                                                 ExportStatus::NoExport|ExportStatus::TestOnly => continue,
1524                                         }
1525                                         let enum_path = format!("{}::{}", module, e.ident);
1526                                         crate_types.opaques.insert(enum_path, &e.ident);
1527                                 }
1528                         },
1529                         syn::Item::Enum(e) => {
1530                                 if let syn::Visibility::Public(_) = e.vis {
1531                                         match export_status(&e.attrs) {
1532                                                 ExportStatus::Export => {},
1533                                                 ExportStatus::NoExport|ExportStatus::TestOnly => continue,
1534                                         }
1535                                         let enum_path = format!("{}::{}", module, e.ident);
1536                                         crate_types.mirrored_enums.insert(enum_path, &e);
1537                                 }
1538                         },
1539                         _ => {},
1540                 }
1541         }
1542 }
1543
1544 fn main() {
1545         let args: Vec<String> = env::args().collect();
1546         if args.len() != 7 {
1547                 eprintln!("Usage: source/dir target/dir source_crate_name derived_templates.rs extra/includes.h extra/cpp/includes.hpp");
1548                 process::exit(1);
1549         }
1550
1551         let mut derived_templates = std::fs::OpenOptions::new().write(true).create(true).truncate(true)
1552                 .open(&args[4]).expect("Unable to open new header file");
1553         let mut header_file = std::fs::OpenOptions::new().write(true).create(true).truncate(true)
1554                 .open(&args[5]).expect("Unable to open new header file");
1555         let mut cpp_header_file = std::fs::OpenOptions::new().write(true).create(true).truncate(true)
1556                 .open(&args[6]).expect("Unable to open new header file");
1557
1558         writeln!(header_file, "#if defined(__GNUC__)").unwrap();
1559         writeln!(header_file, "#define MUST_USE_STRUCT __attribute__((warn_unused))").unwrap();
1560         writeln!(header_file, "#define MUST_USE_RES __attribute__((warn_unused_result))").unwrap();
1561         writeln!(header_file, "#else").unwrap();
1562         writeln!(header_file, "#define MUST_USE_STRUCT").unwrap();
1563         writeln!(header_file, "#define MUST_USE_RES").unwrap();
1564         writeln!(header_file, "#endif").unwrap();
1565         writeln!(header_file, "#if defined(__clang__)").unwrap();
1566         writeln!(header_file, "#define NONNULL_PTR _Nonnull").unwrap();
1567         writeln!(header_file, "#else").unwrap();
1568         writeln!(header_file, "#define NONNULL_PTR").unwrap();
1569         writeln!(header_file, "#endif").unwrap();
1570         writeln!(cpp_header_file, "#include <string.h>\nnamespace LDK {{").unwrap();
1571
1572         // First parse the full crate's ASTs, caching them so that we can hold references to the AST
1573         // objects in other datastructures:
1574         let mut libast = FullLibraryAST { files: HashMap::new() };
1575         load_ast(&args[1], "/lib.rs", "".to_string(), &mut libast);
1576
1577         // ...then walk the ASTs tracking what types we will map, and how, so that we can resolve them
1578         // when parsing other file ASTs...
1579         let mut libtypes = CrateTypes { traits: HashMap::new(), opaques: HashMap::new(), mirrored_enums: HashMap::new(),
1580                 type_aliases: HashMap::new(), templates_defined: HashMap::default(), template_file: &mut derived_templates };
1581         walk_ast(&args[1], "/lib.rs", "".to_string(), &libast, &mut libtypes);
1582
1583         // ... finally, do the actual file conversion/mapping, writing out types as we go.
1584         convert_file(&libast, &mut libtypes, &args[1], &args[2], "/lib.rs", &args[3], "", &mut header_file, &mut cpp_header_file);
1585
1586         // For container templates which we created while walking the crate, make sure we add C++
1587         // mapped types so that C++ users can utilize the auto-destructors available.
1588         for (ty, has_destructor) in libtypes.templates_defined.iter() {
1589                 write_cpp_wrapper(&mut cpp_header_file, ty, *has_destructor);
1590         }
1591         writeln!(cpp_header_file, "}}").unwrap();
1592
1593         header_file.flush().unwrap();
1594         cpp_header_file.flush().unwrap();
1595         derived_templates.flush().unwrap();
1596 }