From: Matt Corallo Date: Wed, 30 Dec 2020 22:30:59 +0000 (-0500) Subject: [bindings] Convert manual `_read` implementations to return Results X-Git-Url: http://git.bitcoin.ninja/?a=commitdiff_plain;h=886fbfc5e84aadf028c8b620dece3fb5a7127973;p=rust-lightning [bindings] Convert manual `_read` implementations to return Results Previously, manual `*_read` implementations were only defined for types with inner fields, which were set to NULL to indicate read errors. This prevents exposing `*_read` for several other types, including tuples (which are needed for `ChannelManager`/ `ChannelMonitors`) and enums (which includes `Event`s, though users likely never need to call that directly). Further, this means we don't expose the actual error enum (which is likely no big deal, but is still nice). Here, we instead create the `Result` type and then pass it through the normal type conversion functions, giving us access to any types which we can convert normally. --- diff --git a/c-bindings-gen/src/main.rs b/c-bindings-gen/src/main.rs index f427b5063..5905f62f8 100644 --- a/c-bindings-gen/src/main.rs +++ b/c-bindings-gen/src/main.rs @@ -58,15 +58,27 @@ fn convert_macro(w: &mut W, macro_path: &syn::Path, stream: & } } -/// Convert "impl trait_path for for_obj { .. }" for manually-mapped types (ie (de)serialization) -fn maybe_convert_trait_impl(w: &mut W, trait_path: &syn::Path, for_obj: &syn::Ident, types: &TypeResolver) { +/// Convert "impl trait_path for for_ty { .. }" for manually-mapped types (ie (de)serialization) +fn maybe_convert_trait_impl(w: &mut W, trait_path: &syn::Path, for_ty: &syn::Type, types: &mut TypeResolver) { if let Some(t) = types.maybe_resolve_path(&trait_path, None) { - let s = types.maybe_resolve_ident(for_obj).unwrap(); - if !types.crate_types.opaques.get(&s).is_some() { return; } + let for_obj; + let full_obj_path; + if let syn::Type::Path(ref p) = for_ty { + if let Some(ident) = p.path.get_ident() { + let s = types.maybe_resolve_ident(ident).unwrap(); + if !types.crate_types.opaques.get(&s).is_some() { return; } + + for_obj = format!("{}", ident); + full_obj_path = for_obj.clone(); + } else { return; } + } else { + return; + } + match &t as &str { "util::ser::Writeable" => { writeln!(w, "#[no_mangle]").unwrap(); - writeln!(w, "pub extern \"C\" fn {}_write(obj: *const {}) -> crate::c_types::derived::CVec_u8Z {{", for_obj, for_obj).unwrap(); + writeln!(w, "pub extern \"C\" fn {}_write(obj: *const {}) -> crate::c_types::derived::CVec_u8Z {{", for_obj, full_obj_path).unwrap(); writeln!(w, "\tcrate::c_types::serialize_obj(unsafe {{ &(*(*obj).inner) }})").unwrap(); writeln!(w, "}}").unwrap(); writeln!(w, "#[no_mangle]").unwrap(); @@ -75,13 +87,41 @@ fn maybe_convert_trait_impl(w: &mut W, trait_path: &syn::Path writeln!(w, "}}").unwrap(); }, "util::ser::Readable" => { + // Create the Result syn::Type + let mut err_segs = syn::punctuated::Punctuated::new(); + err_segs.push(syn::PathSegment { ident: syn::Ident::new("ln", Span::call_site()), arguments: syn::PathArguments::None }); + err_segs.push(syn::PathSegment { ident: syn::Ident::new("msgs", Span::call_site()), arguments: syn::PathArguments::None }); + err_segs.push(syn::PathSegment { ident: syn::Ident::new("DecodeError", Span::call_site()), arguments: syn::PathArguments::None }); + let mut args = syn::punctuated::Punctuated::new(); + args.push(syn::GenericArgument::Type(for_ty.clone())); + args.push(syn::GenericArgument::Type(syn::Type::Path(syn::TypePath { + qself: None, path: syn::Path { + leading_colon: Some(syn::Token![::](Span::call_site())), segments: err_segs, + } + }))); + let mut res_segs = syn::punctuated::Punctuated::new(); + res_segs.push(syn::PathSegment { + ident: syn::Ident::new("Result", Span::call_site()), + arguments: syn::PathArguments::AngleBracketed(syn::AngleBracketedGenericArguments { + colon2_token: None, lt_token: syn::Token![<](Span::call_site()), args, gt_token: syn::Token![>](Span::call_site()), + }) + }); + let res_ty = syn::Type::Path(syn::TypePath { qself: None, path: syn::Path { + leading_colon: None, segments: res_segs } }); + writeln!(w, "#[no_mangle]").unwrap(); - writeln!(w, "pub extern \"C\" fn {}_read(ser: crate::c_types::u8slice) -> {} {{", for_obj, for_obj).unwrap(); - writeln!(w, "\tif let Ok(res) = crate::c_types::deserialize_obj(ser) {{").unwrap(); - writeln!(w, "\t\t{} {{ inner: Box::into_raw(Box::new(res)), is_owned: true }}", for_obj).unwrap(); - writeln!(w, "\t}} else {{").unwrap(); - writeln!(w, "\t\t{} {{ inner: std::ptr::null_mut(), is_owned: true }}", for_obj).unwrap(); - writeln!(w, "\t}}\n}}").unwrap(); + write!(w, "pub extern \"C\" fn {}_read(ser: crate::c_types::u8slice) -> ", for_obj).unwrap(); + types.write_c_type(w, &res_ty, None, false); + writeln!(w, " {{").unwrap(); + writeln!(w, "\tlet res = crate::c_types::deserialize_obj(ser);").unwrap(); + write!(w, "\t").unwrap(); + if types.write_to_c_conversion_new_var(w, &syn::Ident::new("res", Span::call_site()), &res_ty, None, false) { + write!(w, "\n\t").unwrap(); + } + types.write_to_c_conversion_inline_prefix(w, &res_ty, None, false); + write!(w, "res").unwrap(); + types.write_to_c_conversion_inline_suffix(w, &res_ty, None, false); + writeln!(w, "\n}}").unwrap(); }, _ => {}, } @@ -838,12 +878,12 @@ fn writeln_impl(w: &mut W, i: &syn::ItemImpl, types: &mut Typ }, "PartialEq" => {}, // If we have no generics, try a manual implementation: - _ if p.path.get_ident().is_some() => maybe_convert_trait_impl(w, &trait_path.1, &ident, types), + _ if p.path.get_ident().is_some() => maybe_convert_trait_impl(w, &trait_path.1, &*i.self_ty, types), _ => {}, } } else if p.path.get_ident().is_some() { // If we have no generics, try a manual implementation: - maybe_convert_trait_impl(w, &trait_path.1, &ident, types); + maybe_convert_trait_impl(w, &trait_path.1, &*i.self_ty, types); } } else { let declared_type = (*types.get_declared_type(&ident).unwrap()).clone();