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