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.
10 //! It also generates relevant memory-management functions and free-standing functions with
11 //! parameters mapped.
13 use std::collections::HashMap;
16 use std::io::{Read, Write};
20 use proc_macro2::{TokenTree, TokenStream, Span};
27 // *************************************
28 // *** Manually-expanded conversions ***
29 // *************************************
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();
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) {
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));
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();
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();
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));
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();
99 writeln!(w, "}}").unwrap();
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();
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,
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()),
127 let res_ty = syn::Type::Path(syn::TypePath { qself: None, path: syn::Path {
128 leading_colon: None, segments: res_segs } });
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();
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();
149 /// Convert "TraitA : TraitB" to a single function name and return type.
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) {
155 "util::ser::Writeable" => ("write".to_owned(), "crate::c_types::derived::CVec_u8Z"),
156 _ => unimplemented!(),
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) {
164 "util::ser::Writeable" => {
165 writeln!(w, "\t\twrite: {}_write_void,", for_obj).unwrap();
167 _ => unimplemented!(),
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) {
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();
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();
191 // *******************************
192 // *** Per-Type Printing Logic ***
193 // *******************************
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() {
199 syn::TypeParamBound::Trait(supertrait) => {
200 if supertrait.paren_token.is_some() || supertrait.lifetimes.is_some() {
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) {
209 } else if let Some(ident) = supertrait.path.get_ident() {
210 match (&format!("{}", ident) as &str, &ident) {
214 panic!("Supertrait unresolvable and not single-ident");
217 syn::TypeParamBound::Lifetime(_) => unimplemented!(),
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.
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,
235 writeln_docs(w, &t.attrs, "");
237 let mut gen_types = GenericTypes::new();
238 assert!(gen_types.learn_generics(&t.generics, types));
239 gen_types.learn_associated_types(&t, types);
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() {
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,
253 ExportStatus::Export => {},
254 ExportStatus::TestOnly => continue,
256 if m.default.is_some() { unimplemented!(); }
258 gen_types.push_ctx();
259 assert!(gen_types.learn_generics(&m.sig.generics, types));
261 writeln_docs(w, &m.attrs, "\t");
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).
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();
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();
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();
304 &syn::TraitItem::Type(_) => {},
305 _ => unimplemented!(),
308 // Add functions which may be required for supertrait implementations.
309 walk_supertraits!(t, types, (
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());
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());
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());
323 ("Send", _) => {}, ("Sync", _) => {},
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();
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();
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();
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();
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();
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();
367 do_write_impl_trait(w, s, i, &trait_name);
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() {
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() {
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() {
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();
398 if recv.mutability.is_some() {
399 write!(w, "mut self").unwrap();
401 write!(w, "self").unwrap();
404 syn::FnArg::Typed(arg) => {
405 if !arg.attrs.is_empty() { unimplemented!(); }
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() {
412 write!(w, ", {}{}: ", if types.skip_arg(&*arg.ty, Some(&gen_types)) { "_" } else { "" }, ident.ident).unwrap();
414 _ => unimplemented!(),
416 types.write_rust_type(w, Some(&gen_types), &*arg.ty);
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)
428 write!(w, " {{\n\t\t").unwrap();
429 match export_status(&m.attrs) {
430 ExportStatus::NoExport => {
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();
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);
453 writeln!(w, "\n\t}}").unwrap();
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();
463 _ => unimplemented!(),
465 if bounds_iter.next().is_some() { unimplemented!(); }
467 _ => unimplemented!(),
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();
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();
484 write_cpp_wrapper(cpp_headers, &trait_name, true);
485 types.trait_declared(&t.ident, t);
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.
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();
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() {
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 {
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();
558 write_cpp_wrapper(cpp_headers, &format!("{}", ident), true);
561 fn declare_struct<'a, 'b>(s: &'a syn::ItemStruct, types: &mut TypeResolver<'b, 'a>) -> bool {
562 let export = export_status(&s.attrs);
564 ExportStatus::Export => {},
565 ExportStatus::TestOnly => return false,
566 ExportStatus::NoExport => {
567 types.struct_ignored(&s.ident);
572 types.struct_imported(&s.ident, format!("{}", s.ident));
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; }
582 let struct_name = &format!("{}", s.ident);
583 writeln_opaque(w, &s.ident, struct_name, &s.generics, &s.attrs, types, extra_headers, cpp_headers);
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));
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);
595 ExportStatus::Export => {},
596 ExportStatus::NoExport|ExportStatus::TestOnly => {
597 all_fields_settable = false;
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);
615 write!(w, "inner_val").unwrap();
617 write!(w, "(*inner_val)").unwrap();
619 types.write_to_c_conversion_inline_suffix(w, &ref_type, Some(&gen_types), true);
620 writeln!(w, "\n}}").unwrap();
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; }
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);
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();
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();
663 writeln!(w, "\t}})), is_owned: true }}\n}}").unwrap();
668 /// Prints a relevant conversion for impl *
670 /// For simple impl Struct {}s, this just outputs the wrapper functions as Struct_fn_name() { .. }.
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.
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);
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() {
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);
713 let export = export_status(&trait_obj.attrs);
715 ExportStatus::Export => {},
716 ExportStatus::NoExport|ExportStatus::TestOnly => return,
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();
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();
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, $m.sig.ident).unwrap();
749 ExportStatus::TestOnly => continue,
752 let mut printed = false;
753 if let syn::ReturnType::Type(_, rtype) = &$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();
762 write!(w, "{}\t\t{}: {}_{}_{},\n", $indent, $m.sig.ident, ident, trait_obj.ident, $m.sig.ident).unwrap();
766 for item in trait_obj.items.iter() {
768 syn::TraitItem::Method(m) => {
769 write_meth!(m, trait_obj, "");
774 walk_supertraits!(trait_obj, types, (
776 writeln!(w, "\t\tclone: Some({}_clone_void),", ident).unwrap();
778 ("Sync", _) => {}, ("Send", _) => {},
779 ("std::marker::Sync", _) => {}, ("std::marker::Send", _) => {},
781 if let Some(supertrait_obj) = types.crate_types.traits.get(s) {
782 writeln!(w, "\t\t{}: crate::{} {{", t, s).unwrap();
783 writeln!(w, "\t\t\tthis_arg: unsafe {{ (*this_arg).inner as *mut c_void }},").unwrap();
784 writeln!(w, "\t\t\tfree: None,").unwrap();
785 for item in supertrait_obj.items.iter() {
787 syn::TraitItem::Method(m) => {
788 write_meth!(m, supertrait_obj, "\t");
793 write!(w, "\t\t}},\n").unwrap();
795 write_trait_impl_field_assign(w, s, ident);
799 write!(w, "\t}}\n}}\nuse {}::{} as {}TraitImport;\n", types.orig_crate, full_trait_path, trait_obj.ident).unwrap();
801 macro_rules! impl_meth {
802 ($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 == $m.sig.ident).unwrap();
806 match export_status(&trait_method.attrs) {
807 ExportStatus::Export => {},
808 ExportStatus::NoExport|ExportStatus::TestOnly => continue,
811 if let syn::ReturnType::Type(_, _) = &$m.sig.output {
812 writeln!(w, "#[must_use]").unwrap();
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 {
827 write!(w, "unsafe {{ &mut *(this_arg as *mut native{}) }}.{}(", ident, $m.sig.ident).unwrap();
829 write!(w, "{}::{}::{}(", types.orig_crate, resolved_path, $m.sig.ident).unwrap();
832 let mut real_type = "".to_string();
833 match &$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());
843 write_method_call_params(w, &$m.sig, "", types, Some(&gen_types), &real_type, false);
845 write!(w, "\n}}\n").unwrap();
846 if let syn::ReturnType::Type(_, rtype) = &$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();
863 for item in i.items.iter() {
865 syn::ImplItem::Method(m) => {
866 impl_meth!(m, trait_obj, "");
868 syn::ImplItem::Type(_) => {},
869 _ => unimplemented!(),
872 walk_supertraits!(trait_obj, types, (
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() {
878 syn::TraitItem::Method(m) => {
879 impl_meth!(m, supertrait_obj, "\t");
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 {
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();
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),
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);
907 let declared_type = (*types.get_declared_type(&ident).unwrap()).clone();
908 for item in i.items.iter() {
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,
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();
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!(),
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 {
937 if r.mutability.is_some() { takes_mut_self = true; }
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();
945 write!(w, "{}::{}::{}(", types.orig_crate, resolved_path, m.sig.ident).unwrap();
947 write_method_call_params(w, &m.sig, "", types, Some(&gen_types), &ret_type, false);
949 writeln!(w, "\n}}\n").unwrap();
957 eprintln!("Not implementing anything for {} due to no-resolve (probably the type isn't pub or its marked not exported)", ident);
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,
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,
988 if is_enum_opaque(e) {
989 types.enum_ignored(&e.ident);
991 types.mirrored_enum_declared(&e.ident);
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
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,
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);
1010 writeln_docs(w, &e.attrs, "");
1012 if e.generics.lt_token.is_some() {
1016 let mut needs_free = false;
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 {
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();
1032 write!(w, "\t}}").unwrap();
1034 if var.discriminant.is_some() { unimplemented!(); }
1035 writeln!(w, ",").unwrap();
1037 writeln!(w, "}}\nuse {}::{}::{} as native{};\nimpl {} {{", types.orig_crate, types.module_path, e.ident, e.ident, e.ident).unwrap();
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();
1050 write!(w, "}} ").unwrap();
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)
1062 types.write_from_c_conversion_new_var(&mut out, field.ident.as_ref().unwrap(), &field.ty, None)
1064 if $ref || new_var {
1066 write!(w, "let mut {}_nonref = (*{}).clone();\n\t\t\t\t", field.ident.as_ref().unwrap(), field.ident.as_ref().unwrap()).unwrap();
1068 let nonref_ident = syn::Ident::new(&format!("{}_nonref", field.ident.as_ref().unwrap()), Span::call_site());
1070 types.write_to_c_conversion_new_var(w, &nonref_ident, &field.ty, None, false);
1072 types.write_from_c_conversion_new_var(w, &nonref_ident, &field.ty, None);
1074 write!(w, "\n\t\t\t\t").unwrap();
1077 write!(w, "\n\t\t\t\t").unwrap();
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();
1089 types.write_to_c_conversion_inline_prefix(w, &field.ty, None, false);
1091 types.write_from_c_conversion_prefix(w, &field.ty, None);
1094 field.ident.as_ref().unwrap(),
1095 if $ref { "_nonref" } else { "" }).unwrap();
1097 types.write_to_c_conversion_inline_suffix(w, &field.ty, None, false);
1099 types.write_from_c_conversion_suffix(w, &field.ty, None);
1101 write!(w, ",").unwrap();
1103 writeln!(w, "\n\t\t\t\t}}").unwrap();
1104 write!(w, "\t\t\t}}").unwrap();
1106 writeln!(w, ",").unwrap();
1108 writeln!(w, "\t\t}}\n\t}}").unwrap();
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();
1119 writeln!(w, "#[no_mangle]\npub extern \"C\" fn {}_free(this_ptr: {}) {{ }}", e.ident, e.ident).unwrap();
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);
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,
1133 writeln_docs(w, &f.attrs, "");
1135 let mut gen_types = GenericTypes::new();
1136 if !gen_types.learn_generics(&f.sig.generics, types) { return; }
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();
1147 // ********************************
1148 // *** File/Crate Walking Logic ***
1149 // ********************************
1151 /// Simple utility to walk the modules in a crate - iterating over the modules (with file paths) in
1153 struct FileIter<'a, I: Iterator<Item = &'a syn::Item>> {
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> {
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,
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));
1177 format!("{}/{}/mod.rs", (self.path.as_ref() as &Path).parent().unwrap().display(), m.ident),
1183 None => return None,
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() }
1193 /// A struct containing the syn::File AST for each file in the crate.
1194 struct FullLibraryAST {
1195 files: HashMap<String, syn::File>,
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 };
1204 assert!(syntax.shebang.is_none()); // Not sure what this is, hope we dont have one
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");
1211 assert_eq!(export_status(&syntax.attrs), ExportStatus::Export);
1212 writeln_docs(&mut out, &syntax.attrs, "");
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();
1229 writeln!(out, "\nuse std::ffi::c_void;\nuse bitcoin::hashes::Hash;\nuse crate::c_types::*;\n").unwrap();
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);
1239 eprintln!("Converting {} entries...", path);
1241 let mut type_resolver = TypeResolver::new(orig_crate, module, crate_types);
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() {
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);
1252 syn::Item::Enum(e) => {
1253 if let syn::Visibility::Public(_) = e.vis {
1254 declare_enum(&e, &mut type_resolver);
1261 for item in syntax.items.iter() {
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);
1270 syn::Item::Impl(i) => {
1271 writeln_impl(&mut out, &i, &mut type_resolver);
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);
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);
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();
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,
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; }
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),
1317 syn::Item::Fn(f) => {
1318 if let syn::Visibility::Public(_) = f.vis {
1319 writeln_fn(&mut out, &f, &mut type_resolver);
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);
1327 syn::Item::Verbatim(_) => {},
1328 syn::Item::ExternCrate(_) => {},
1329 _ => unimplemented!(),
1333 out.flush().unwrap();
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);
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");
1345 assert_eq!(export_status(&syntax.attrs), ExportStatus::Export);
1347 for (path, new_mod, _) in file_iter(&syntax, in_dir, path, &module) {
1348 load_ast(in_dir, &path, new_mod, ast_storage);
1350 ast_storage.files.insert(module, syntax);
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>) {
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);
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 });
1364 syn::UseTree::Group(g) => {
1365 for i in g.items.iter() {
1366 process_use_intern(i, path.clone(), imports);
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 {
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();
1381 } else { unimplemented!(); }
1383 syn::Type::Reference(r) => {
1384 r.elem = Box::new(resolve_imported_refs(imports, (*r.elem).clone()));
1386 syn::Type::Slice(s) => {
1387 s.elem = Box::new(resolve_imported_refs(imports, (*s.elem).clone()));
1389 syn::Type::Tuple(t) => {
1390 for e in t.elems.iter_mut() {
1391 *e = resolve_imported_refs(imports, e.clone());
1394 _ => unimplemented!(),
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);
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);
1408 let mut import_maps = HashMap::new();
1410 for item in syntax.items.iter() {
1412 syn::Item::Use(u) => {
1413 process_use_intern(&u.tree, syn::punctuated::Punctuated::new(), &mut import_maps);
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,
1421 let struct_path = format!("{}::{}", module, s.ident);
1422 crate_types.opaques.insert(struct_path, &s.ident);
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,
1431 let trait_path = format!("{}::{}", module, t.ident);
1432 crate_types.traits.insert(trait_path, &t);
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,
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; }
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);
1454 crate_types.type_aliases.insert(type_path, resolve_imported_refs(&import_maps, (*t.ty).clone()));
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,
1466 let enum_path = format!("{}::{}", module, e.ident);
1467 crate_types.opaques.insert(enum_path, &e.ident);
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,
1476 let enum_path = format!("{}::{}", module, e.ident);
1477 crate_types.mirrored_enums.insert(enum_path, &e);
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");
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");
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();
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);
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);
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);
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);
1524 writeln!(cpp_header_file, "}}").unwrap();
1526 header_file.flush().unwrap();
1527 cpp_header_file.flush().unwrap();
1528 derived_templates.flush().unwrap();