(Partially) support supertraits with generic bounds
[ldk-c-bindings] / c-bindings-gen / src / main.rs
index 42fd470da778207a5dcd039c56dc869e670b3c1d..975db567dcbc35cb560c88cd6f433b288e69b0de 100644 (file)
@@ -102,7 +102,7 @@ fn maybe_convert_trait_impl<W: std::io::Write>(w: &mut W, trait_path: &syn::Path
                        },
                        "lightning::util::ser::Readable"|"lightning::util::ser::ReadableArgs"|"lightning::util::ser::MaybeReadable" => {
                                // Create the Result<Object, DecodeError> syn::Type
-                               let mut res_ty: syn::Type = parse_quote!(Result<#for_ty, ::ln::msgs::DecodeError>);
+                               let mut res_ty: syn::Type = parse_quote!(Result<#for_ty, lightning::ln::msgs::DecodeError>);
 
                                writeln!(w, "#[no_mangle]").unwrap();
                                writeln!(w, "/// Read a {} from a byte array, created by {}_write", for_obj, for_obj).unwrap();
@@ -151,7 +151,7 @@ fn maybe_convert_trait_impl<W: std::io::Write>(w: &mut W, trait_path: &syn::Path
                                                } else { unreachable!(); }
                                        } else { unreachable!(); }
                                } else if t == "lightning::util::ser::MaybeReadable" {
-                                       res_ty = parse_quote!(Result<Option<#for_ty>, ::ln::msgs::DecodeError>);
+                                       res_ty = parse_quote!(Result<Option<#for_ty>, lightning::ln::msgs::DecodeError>);
                                }
                                write!(w, ") -> ").unwrap();
                                types.write_c_type(w, &res_ty, Some(generics), false);
@@ -244,14 +244,15 @@ macro_rules! walk_supertraits { ($t: expr, $types: expr, ($( $($pat: pat)|* => $
                                        let types_opt: Option<&TypeResolver> = $types;
                                        if let Some(types) = types_opt {
                                                if let Some(path) = types.maybe_resolve_path(&supertrait.path, None) {
-                                                       match (&path as &str, &supertrait.path.segments.iter().last().unwrap().ident) {
+                                                       let last_seg = supertrait.path.segments.iter().last().unwrap();
+                                                       match (&path as &str, &last_seg.ident, &last_seg.arguments) {
                                                                $( $($pat)|* => $e, )*
                                                        }
                                                        continue;
                                                }
                                        }
                                        if let Some(ident) = supertrait.path.get_ident() {
-                                               match (&format!("{}", ident) as &str, &ident) {
+                                               match (&format!("{}", ident) as &str, &ident, &syn::PathArguments::None) {
                                                        $( $($pat)|* => $e, )*
                                                }
                                        } else if types_opt.is_some() {
@@ -292,14 +293,14 @@ fn writeln_trait<'a, 'b, W: std::io::Write>(w: &mut W, t: &'a syn::ItemTrait, ty
        }
        writeln_docs(w, &t.attrs, "");
 
-       let mut gen_types = GenericTypes::new(None);
+       let mut gen_types = GenericTypes::new(Some(format!("{}::{}", types.module_path, trait_name)));
 
        // Add functions which may be required for supertrait implementations.
        // Due to borrow checker limitations, we only support one in-crate supertrait here.
        let supertrait_name;
        let supertrait_resolver;
        walk_supertraits!(t, Some(&types), (
-               (s, _i) => {
+               (s, _i, _) => {
                        if let Some(supertrait) = types.crate_types.traits.get(s) {
                                supertrait_name = s.to_string();
                                supertrait_resolver = get_module_type_resolver!(supertrait_name, types.crate_libs, types.crate_types);
@@ -385,20 +386,20 @@ fn writeln_trait<'a, 'b, W: std::io::Write>(w: &mut W, t: &'a syn::ItemTrait, ty
        }
        // Add functions which may be required for supertrait implementations.
        walk_supertraits!(t, Some(&types), (
-               ("Clone", _) => {
+               ("Clone", _, _) => {
                        writeln!(w, "\t/// Called, if set, after this {} has been cloned into a duplicate object.", trait_name).unwrap();
                        writeln!(w, "\t/// The new {} is provided, and should be mutated as needed to perform a", trait_name).unwrap();
                        writeln!(w, "\t/// deep copy of the object pointed to by this_arg or avoid any double-freeing.").unwrap();
                        writeln!(w, "\tpub cloned: Option<extern \"C\" fn (new_{}: &mut {})>,", trait_name, trait_name).unwrap();
                        generated_fields.push(("cloned".to_owned(), None, None));
                },
-               ("std::cmp::Eq", _)|("core::cmp::Eq", _) => {
+               ("std::cmp::Eq", _, _)|("core::cmp::Eq", _, _) => {
                        let eq_docs = "Checks if two objects are equal given this object's this_arg pointer and another object.";
                        writeln!(w, "\t/// {}", eq_docs).unwrap();
                        writeln!(w, "\tpub eq: extern \"C\" fn (this_arg: *const c_void, other_arg: &{}) -> bool,", trait_name).unwrap();
                        generated_fields.push(("eq".to_owned(), None, Some(format!("\t/** {} */\n", eq_docs))));
                },
-               ("std::hash::Hash", _)|("core::hash::Hash", _) => {
+               ("std::hash::Hash", _, _)|("core::hash::Hash", _, _) => {
                        let hash_docs_a = "Calculate a succinct non-cryptographic hash for an object given its this_arg pointer.";
                        let hash_docs_b = "This is used, for example, for inclusion of this object in a hash map.";
                        writeln!(w, "\t/// {}", hash_docs_a).unwrap();
@@ -407,15 +408,15 @@ fn writeln_trait<'a, 'b, W: std::io::Write>(w: &mut W, t: &'a syn::ItemTrait, ty
                        generated_fields.push(("hash".to_owned(), None,
                                Some(format!("\t/**\n\t * {}\n\t * {}\n\t */\n", hash_docs_a, hash_docs_b))));
                },
-               ("Send", _) => {}, ("Sync", _) => {},
-               ("std::fmt::Debug", _)|("core::fmt::Debug", _) => {
+               ("Send", _, _) => {}, ("Sync", _, _) => {},
+               ("std::fmt::Debug", _, _)|("core::fmt::Debug", _, _) => {
                        let debug_docs = "Return a human-readable \"debug\" string describing this object";
                        writeln!(w, "\t/// {}", debug_docs).unwrap();
                        writeln!(w, "\tpub debug_str: extern \"C\" fn (this_arg: *const c_void) -> crate::c_types::Str,").unwrap();
                        generated_fields.push(("debug_str".to_owned(), None,
                                Some(format!("\t/**\n\t * {}\n\t */\n", debug_docs))));
                },
-               (s, i) => {
+               (s, i, _) => {
                        // TODO: Both of the below should expose supertrait methods in C++, but doing so is
                        // nontrivial.
                        generated_fields.push(if types.crate_types.traits.get(s).is_none() {
@@ -441,7 +442,9 @@ fn writeln_trait<'a, 'b, W: std::io::Write>(w: &mut W, t: &'a syn::ItemTrait, ty
        writeln!(w, "}}").unwrap();
 
        macro_rules! impl_trait_for_c {
-               ($t: expr, $impl_accessor: expr, $type_resolver: expr) => {
+               ($t: expr, $impl_accessor: expr, $type_resolver: expr, $generic_impls: expr) => {
+                       let mut trait_gen_types = gen_types.push_ctx();
+                       assert!(trait_gen_types.learn_generics_with_impls(&$t.generics, $generic_impls, $type_resolver));
                        for item in $t.items.iter() {
                                match item {
                                        syn::TraitItem::Method(m) => {
@@ -450,7 +453,7 @@ fn writeln_trait<'a, 'b, W: std::io::Write>(w: &mut W, t: &'a syn::ItemTrait, ty
                                                                m.sig.abi.is_some() || m.sig.variadic.is_some() {
                                                        panic!("1");
                                                }
-                                               let mut meth_gen_types = gen_types.push_ctx();
+                                               let mut meth_gen_types = trait_gen_types.push_ctx();
                                                assert!(meth_gen_types.learn_generics(&m.sig.generics, $type_resolver));
                                                // Note that we do *not* use the method generics when printing "native"
                                                // rust parts - if the method is generic, we need to print a generic
@@ -565,17 +568,17 @@ fn writeln_trait<'a, 'b, W: std::io::Write>(w: &mut W, t: &'a syn::ItemTrait, ty
 
        // Implement supertraits for the C-mapped struct.
        walk_supertraits!(t, Some(&types), (
-               ("std::cmp::Eq", _)|("core::cmp::Eq", _) => {
+               ("std::cmp::Eq", _, _)|("core::cmp::Eq", _, _) => {
                        writeln!(w, "impl core::cmp::Eq for {} {{}}", trait_name).unwrap();
                        writeln!(w, "impl core::cmp::PartialEq for {} {{", trait_name).unwrap();
                        writeln!(w, "\tfn eq(&self, o: &Self) -> bool {{ (self.eq)(self.this_arg, o) }}\n}}").unwrap();
                },
-               ("std::hash::Hash", _)|("core::hash::Hash", _) => {
+               ("std::hash::Hash", _, _)|("core::hash::Hash", _, _) => {
                        writeln!(w, "impl core::hash::Hash for {} {{", trait_name).unwrap();
                        writeln!(w, "\tfn hash<H: core::hash::Hasher>(&self, hasher: &mut H) {{ hasher.write_u64((self.hash)(self.this_arg)) }}\n}}").unwrap();
                },
-               ("Send", _) => {}, ("Sync", _) => {},
-               ("Clone", _) => {
+               ("Send", _, _) => {}, ("Sync", _, _) => {},
+               ("Clone", _, _) => {
                        writeln!(w, "#[no_mangle]").unwrap();
                        writeln!(w, "/// Creates a copy of a {}", trait_name).unwrap();
                        writeln!(w, "pub extern \"C\" fn {}_clone(orig: &{}) -> {} {{", trait_name, trait_name, trait_name).unwrap();
@@ -587,14 +590,14 @@ fn writeln_trait<'a, 'b, W: std::io::Write>(w: &mut W, t: &'a syn::ItemTrait, ty
                        writeln!(w, "\t\t{}_clone(self)", trait_name).unwrap();
                        writeln!(w, "\t}}\n}}").unwrap();
                },
-               ("std::fmt::Debug", _)|("core::fmt::Debug", _) => {
+               ("std::fmt::Debug", _, _)|("core::fmt::Debug", _, _) => {
                        writeln!(w, "impl core::fmt::Debug for {} {{", trait_name).unwrap();
                        writeln!(w, "\tfn fmt(&self, f: &mut core::fmt::Formatter) -> Result<(), core::fmt::Error> {{").unwrap();
                        writeln!(w, "\t\tf.write_str((self.debug_str)(self.this_arg).into_str())").unwrap();
                        writeln!(w, "\t}}").unwrap();
                        writeln!(w, "}}").unwrap();
                },
-               (s, i) => {
+               (s, i, generic_args) => {
                        if let Some(supertrait) = types.crate_types.traits.get(s) {
                                let resolver = get_module_type_resolver!(s, types.crate_libs, types.crate_types);
 
@@ -604,10 +607,10 @@ fn writeln_trait<'a, 'b, W: std::io::Write>(w: &mut W, t: &'a syn::ItemTrait, ty
                                write!(w, "impl").unwrap();
                                maybe_write_lifetime_generics(w, &supertrait.generics, types);
                                write!(w, " {}", s).unwrap();
-                               maybe_write_generics(w, &supertrait.generics, types, false);
+                               maybe_write_generics(w, &supertrait.generics, generic_args, types, false);
                                writeln!(w, " for {} {{", trait_name).unwrap();
 
-                               impl_trait_for_c!(supertrait, format!(".{}", i), &resolver);
+                               impl_trait_for_c!(supertrait, format!(".{}", i), &resolver, generic_args);
                                writeln!(w, "}}").unwrap();
                        } else {
                                do_write_impl_trait(w, s, i, &trait_name);
@@ -621,9 +624,9 @@ fn writeln_trait<'a, 'b, W: std::io::Write>(w: &mut W, t: &'a syn::ItemTrait, ty
                write!(w, "impl").unwrap();
                maybe_write_lifetime_generics(w, &t.generics, types);
                write!(w, " rust{}", t.ident).unwrap();
-               maybe_write_generics(w, &t.generics, types, false);
+               maybe_write_generics(w, &t.generics, &syn::PathArguments::None, types, false);
                writeln!(w, " for {} {{", trait_name).unwrap();
-               impl_trait_for_c!(t, "", types);
+               impl_trait_for_c!(t, "", types, &syn::PathArguments::None);
                writeln!(w, "}}\n").unwrap();
                writeln!(w, "// We're essentially a pointer already, or at least a set of pointers, so allow us to be used").unwrap();
                writeln!(w, "// directly as a Deref trait in higher-level structs:").unwrap();
@@ -652,7 +655,7 @@ fn writeln_opaque<W: std::io::Write>(w: &mut W, ident: &syn::Ident, struct_name:
        // https://github.com/eqrion/cbindgen/issues/286 Thus, instead, we import it as a temporary
        // name and then reference it by that name, which works around the issue.
        write!(w, "\nuse {}::{} as native{}Import;\npub(crate) type native{} = native{}Import", types.module_path, ident, ident, ident, ident).unwrap();
-       maybe_write_generics(w, &generics, &types, true);
+       maybe_write_generics(w, &generics, &syn::PathArguments::None, &types, true);
        writeln!(w, ";\n").unwrap();
        writeln!(extra_headers, "struct native{}Opaque;\ntypedef struct native{}Opaque LDKnative{};", ident, ident, ident).unwrap();
        writeln_docs(w, &attrs, "");
@@ -735,6 +738,25 @@ fn writeln_struct<'a, 'b, W: std::io::Write>(w: &mut W, s: &'a syn::ItemStruct,
                                                write!(w, "inner_val").unwrap();
                                                types.write_to_c_conversion_inline_suffix(w, &ref_type, Some(&gen_types), true);
                                                writeln!(w, "\n}}").unwrap();
+                                       } else {
+                                               // If the type isn't reference-able, but is clonable, export a getter that just clones
+                                               if types.understood_c_type(&$field.ty, Some(&gen_types)) {
+                                                       let mut v = Vec::new();
+                                                       types.write_c_type(&mut v, &$field.ty, Some(&gen_types), true);
+                                                       let s = String::from_utf8(v).unwrap();
+                                                       if types.is_clonable(&s) {
+                                                               writeln_arg_docs(w, &$field.attrs, "", types, Some(&gen_types), vec![].drain(..), Some(&$field.ty));
+                                                               writeln!(w, "///\n/// Returns a copy of the field.").unwrap();
+                                                               write!(w, "#[no_mangle]\npub extern \"C\" fn {}_get_{}(this_ptr: &{}) -> {}", struct_name, $new_name, struct_name, s).unwrap();
+                                                               write!(w, " {{\n\tlet mut inner_val = this_ptr.get_native_mut_ref().{}.clone();\n\t", $real_name).unwrap();
+                                                               let local_var = types.write_to_c_conversion_new_var(w, &format_ident!("inner_val"), &$field.ty, Some(&gen_types), true);
+                                                               if local_var { write!(w, "\n\t").unwrap(); }
+                                                               types.write_to_c_conversion_inline_prefix(w, &$field.ty, Some(&gen_types), true);
+                                                               write!(w, "inner_val").unwrap();
+                                                               types.write_to_c_conversion_inline_suffix(w, &$field.ty, Some(&gen_types), true);
+                                                               writeln!(w, "\n}}").unwrap();
+                                                       }
+                                               }
                                        }
                                }
 
@@ -914,7 +936,7 @@ fn writeln_impl<W: std::io::Write>(w: &mut W, i: &syn::ItemImpl, types: &mut Typ
                                                let supertrait_name;
                                                let supertrait_resolver;
                                                walk_supertraits!(trait_obj, Some(&types), (
-                                                       (s, _i) => {
+                                                       (s, _i, _) => {
                                                                if let Some(supertrait) = types.crate_types.traits.get(s) {
                                                                        supertrait_name = s.to_string();
                                                                        supertrait_resolver = get_module_type_resolver!(supertrait_name, types.crate_libs, types.crate_types);
@@ -928,7 +950,7 @@ fn writeln_impl<W: std::io::Write>(w: &mut W, i: &syn::ItemImpl, types: &mut Typ
                                                // mappings from a trai defined in a different file, we may mis-resolve or
                                                // fail to resolve the mapped types. Thus, we have to construct a new
                                                // resolver for the module that the trait was defined in here first.
-                                               let trait_resolver = get_module_type_resolver!(full_trait_path, types.crate_libs, types.crate_types);
+                                               let mut trait_resolver = get_module_type_resolver!(full_trait_path, types.crate_libs, types.crate_types);
                                                gen_types.learn_associated_types(trait_obj, &trait_resolver);
                                                let mut impl_associated_types = HashMap::new();
                                                for item in i.items.iter() {
@@ -1029,14 +1051,14 @@ fn writeln_impl<W: std::io::Write>(w: &mut W, i: &syn::ItemImpl, types: &mut Typ
                                                }
                                                let mut requires_clone = false;
                                                walk_supertraits!(trait_obj, Some(&types), (
-                                                       ("Clone", _) => {
+                                                       ("Clone", _, _) => {
                                                                requires_clone = true;
                                                                writeln!(w, "\t\tcloned: Some({}_{}_cloned),", trait_obj.ident, ident).unwrap();
                                                        },
-                                                       ("Sync", _) => {}, ("Send", _) => {},
-                                                       ("std::marker::Sync", _) => {}, ("std::marker::Send", _) => {},
-                                                       ("core::fmt::Debug", _) => {},
-                                                       (s, t) => {
+                                                       ("Sync", _, _) => {}, ("Send", _, _) => {},
+                                                       ("std::marker::Sync", _, _) => {}, ("std::marker::Send", _, _) => {},
+                                                       ("core::fmt::Debug", _, _) => {},
+                                                       (s, t, _) => {
                                                                if let Some(supertrait_obj) = types.crate_types.traits.get(s) {
                                                                        writeln!(w, "\t\t{}: crate::{} {{", t, s).unwrap();
                                                                        writeln!(w, "\t\t\tthis_arg: unsafe {{ ObjOps::untweak_ptr((*this_arg).inner) as *mut c_void }},").unwrap();
@@ -1088,17 +1110,12 @@ fn writeln_impl<W: std::io::Write>(w: &mut W, i: &syn::ItemImpl, types: &mut Typ
                                                                                _ => {}
                                                                        }
                                                                }
-                                                               if uncallable_function {
-                                                                       let mut trait_resolver = get_module_type_resolver!(full_trait_path, $types.crate_libs, $types.crate_types);
-                                                                       write_method_params(w, &$trait_meth.sig, "c_void", &mut trait_resolver, Some(&meth_gen_types), true, true);
-                                                               } else {
-                                                                       write_method_params(w, &$m.sig, "c_void", $types, Some(&meth_gen_types), true, true);
-                                                               }
+                                                               write_method_params(w, &$trait_meth.sig, "c_void", &mut trait_resolver, Some(&meth_gen_types), true, true);
                                                                write!(w, " {{\n\t").unwrap();
                                                                if uncallable_function {
                                                                        write!(w, "unreachable!();").unwrap();
                                                                } else {
-                                                                       write_method_var_decl_body(w, &$m.sig, "", $types, Some(&meth_gen_types), false);
+                                                                       write_method_var_decl_body(w, &$trait_meth.sig, "", &mut trait_resolver, Some(&meth_gen_types), false);
                                                                        let mut takes_self = false;
                                                                        for inp in $m.sig.inputs.iter() {
                                                                                if let syn::FnArg::Receiver(_) = inp {
@@ -1111,6 +1128,14 @@ fn writeln_impl<W: std::io::Write>(w: &mut W, i: &syn::ItemImpl, types: &mut Typ
                                                                                if idx != 0 { t_gen_args += ", " };
                                                                                t_gen_args += "_"
                                                                        }
+                                                                       // rustc doesn't like <_> if the _ is actually a lifetime, so
+                                                                       // if all the parameters are lifetimes just skip it.
+                                                                       let mut nonlifetime_param = false;
+                                                                       for param in $trait.generics.params.iter() {
+                                                                               if let syn::GenericParam::Lifetime(_) = param {}
+                                                                               else { nonlifetime_param = true; }
+                                                                       }
+                                                                       if !nonlifetime_param { t_gen_args = String::new(); }
                                                                        if takes_self {
                                                                                write!(w, "<native{} as {}<{}>>::{}(unsafe {{ &mut *(this_arg as *mut native{}) }}, ", ident, $trait_path, t_gen_args, $m.sig.ident, ident).unwrap();
                                                                        } else {
@@ -1128,7 +1153,7 @@ fn writeln_impl<W: std::io::Write>(w: &mut W, i: &syn::ItemImpl, types: &mut Typ
                                                                                },
                                                                                _ => {},
                                                                        }
-                                                                       write_method_call_params(w, &$m.sig, "", $types, Some(&meth_gen_types), &real_type, false);
+                                                                       write_method_call_params(w, &$trait_meth.sig, "", &mut trait_resolver, Some(&meth_gen_types), &real_type, false);
                                                                }
                                                                write!(w, "\n}}\n").unwrap();
                                                                if let syn::ReturnType::Type(_, rtype) = &$m.sig.output {
@@ -1166,7 +1191,6 @@ fn writeln_impl<W: std::io::Write>(w: &mut W, i: &syn::ItemImpl, types: &mut Typ
                                                                        assert!(meth.default.is_some());
                                                                        let old_gen_types = gen_types;
                                                                        gen_types = GenericTypes::new(Some(resolved_path.clone()));
-                                                                       let mut trait_resolver = get_module_type_resolver!(full_trait_path, types.crate_libs, types.crate_types);
                                                                        impl_meth!(meth, meth, full_trait_path, trait_obj, "", &mut trait_resolver);
                                                                        gen_types = old_gen_types;
                                                                },
@@ -1178,7 +1202,7 @@ fn writeln_impl<W: std::io::Write>(w: &mut W, i: &syn::ItemImpl, types: &mut Typ
                                                        writeln!(w, "\tnew_obj.this_arg = {}_clone_void(new_obj.this_arg);", ident).unwrap();
                                                        writeln!(w, "\tnew_obj.free = Some({}_free_void);", ident).unwrap();
                                                        walk_supertraits!(trait_obj, Some(&types), (
-                                                               (s, t) => {
+                                                               (s, t, _) => {
                                                                        if types.crate_types.traits.get(s).is_some() {
                                                                                assert!(!types.is_clonable(s)); // We don't currently support cloning with a clonable supertrait
                                                                                writeln!(w, "\tnew_obj.{}.this_arg = new_obj.this_arg;", t).unwrap();
@@ -1708,7 +1732,7 @@ fn writeln_enum<'a, 'b, W: std::io::Write>(w: &mut W, e: &'a syn::ItemEnum, type
        }
        writeln!(w, "}}\nuse {}::{} as {}Import;", types.module_path, e.ident, e.ident).unwrap();
        write!(w, "pub(crate) type native{} = {}Import", e.ident, e.ident).unwrap();
-       maybe_write_generics(w, &e.generics, &types, true);
+       maybe_write_generics(w, &e.generics, &syn::PathArguments::None, &types, true);
        writeln!(w, ";\n\nimpl {} {{", e.ident).unwrap();
 
        macro_rules! write_conv {
@@ -1877,7 +1901,7 @@ fn writeln_fn<'a, 'b, W: std::io::Write>(w: &mut W, f: &'a syn::ItemFn, types: &
        write!(w, "{}::{}", types.module_path, f.sig.ident).unwrap();
 
        let mut function_generic_args = Vec::new();
-       maybe_write_generics(&mut function_generic_args, &f.sig.generics, types, true);
+       maybe_write_generics(&mut function_generic_args, &f.sig.generics, &syn::PathArguments::None, types, true);
        if !function_generic_args.is_empty() {
                write!(w, "::{}", String::from_utf8(function_generic_args).unwrap()).unwrap();
        }
@@ -2180,10 +2204,10 @@ fn walk_ast_first_pass<'a>(ast_storage: &'a FullLibraryAST, crate_types: &mut Cr
                                                }
                                                let trait_path = format!("{}::{}", module, t.ident);
                                                walk_supertraits!(t, None, (
-                                                       ("Clone", _) => {
+                                                       ("Clone", _, _) => {
                                                                crate_types.set_clonable("crate::".to_owned() + &trait_path);
                                                        },
-                                                       (_, _) => {}
+                                                       (_, _, _) => {}
                                                ) );
                                                crate_types.traits.insert(trait_path, &t);
                                        }