| use proc_macro2::TokenStream; |
| use quote::quote; |
| use syn::parse_quote; |
| |
| pub fn type_decodable_derive(mut s: synstructure::Structure<'_>) -> proc_macro2::TokenStream { |
| let decoder_ty = quote! { __D }; |
| if !s.ast().generics.lifetimes().any(|lt| lt.lifetime.ident == "tcx") { |
| s.add_impl_generic(parse_quote! { 'tcx }); |
| } |
| s.add_impl_generic(parse_quote! {#decoder_ty: ::rustc_middle::ty::codec::TyDecoder<'tcx>}); |
| s.add_bounds(synstructure::AddBounds::Generics); |
| |
| decodable_body(s, decoder_ty) |
| } |
| |
| pub fn meta_decodable_derive(mut s: synstructure::Structure<'_>) -> proc_macro2::TokenStream { |
| if !s.ast().generics.lifetimes().any(|lt| lt.lifetime.ident == "tcx") { |
| s.add_impl_generic(parse_quote! { 'tcx }); |
| } |
| s.add_impl_generic(parse_quote! { '__a }); |
| let decoder_ty = quote! { DecodeContext<'__a, 'tcx> }; |
| s.add_bounds(synstructure::AddBounds::Generics); |
| |
| decodable_body(s, decoder_ty) |
| } |
| |
| pub fn decodable_derive(mut s: synstructure::Structure<'_>) -> proc_macro2::TokenStream { |
| let decoder_ty = quote! { __D }; |
| s.add_impl_generic(parse_quote! {#decoder_ty: ::rustc_serialize::Decoder}); |
| s.add_bounds(synstructure::AddBounds::Generics); |
| |
| decodable_body(s, decoder_ty) |
| } |
| |
| fn decodable_body( |
| s: synstructure::Structure<'_>, |
| decoder_ty: TokenStream, |
| ) -> proc_macro2::TokenStream { |
| if let syn::Data::Union(_) = s.ast().data { |
| panic!("cannot derive on union") |
| } |
| let ty_name = s.ast().ident.to_string(); |
| let decode_body = match s.variants() { |
| [vi] => { |
| let construct = vi.construct(|field, index| decode_field(field, index, true)); |
| let n_fields = vi.ast().fields.len(); |
| quote! { |
| ::rustc_serialize::Decoder::read_struct( |
| __decoder, |
| #ty_name, |
| #n_fields, |
| |__decoder| { ::std::result::Result::Ok(#construct) }, |
| ) |
| } |
| } |
| variants => { |
| let match_inner: TokenStream = variants |
| .iter() |
| .enumerate() |
| .map(|(idx, vi)| { |
| let construct = vi.construct(|field, index| decode_field(field, index, false)); |
| quote! { #idx => { ::std::result::Result::Ok(#construct) } } |
| }) |
| .collect(); |
| let names: TokenStream = variants |
| .iter() |
| .map(|vi| { |
| let variant_name = vi.ast().ident.to_string(); |
| quote!(#variant_name,) |
| }) |
| .collect(); |
| let message = format!( |
| "invalid enum variant tag while decoding `{}`, expected 0..{}", |
| ty_name, |
| variants.len() |
| ); |
| quote! { |
| ::rustc_serialize::Decoder::read_enum( |
| __decoder, |
| #ty_name, |
| |__decoder| { |
| ::rustc_serialize::Decoder::read_enum_variant( |
| __decoder, |
| &[#names], |
| |__decoder, __variant_idx| { |
| match __variant_idx { |
| #match_inner |
| _ => return ::std::result::Result::Err( |
| ::rustc_serialize::Decoder::error(__decoder, #message)), |
| } |
| }) |
| } |
| ) |
| } |
| } |
| }; |
| |
| s.bound_impl( |
| quote!(::rustc_serialize::Decodable<#decoder_ty>), |
| quote! { |
| fn decode( |
| __decoder: &mut #decoder_ty, |
| ) -> ::std::result::Result<Self, <#decoder_ty as ::rustc_serialize::Decoder>::Error> { |
| #decode_body |
| } |
| }, |
| ) |
| } |
| |
| fn decode_field(field: &syn::Field, index: usize, is_struct: bool) -> proc_macro2::TokenStream { |
| let decode_inner_method = if let syn::Type::Reference(_) = field.ty { |
| quote! { ::rustc_middle::ty::codec::RefDecodable::decode } |
| } else { |
| quote! { ::rustc_serialize::Decodable::decode } |
| }; |
| let (decode_method, opt_field_name) = if is_struct { |
| let field_name = field.ident.as_ref().map_or_else(|| index.to_string(), |i| i.to_string()); |
| ( |
| proc_macro2::Ident::new("read_struct_field", proc_macro2::Span::call_site()), |
| quote! { #field_name, }, |
| ) |
| } else { |
| ( |
| proc_macro2::Ident::new("read_enum_variant_arg", proc_macro2::Span::call_site()), |
| quote! {}, |
| ) |
| }; |
| |
| quote! { |
| match ::rustc_serialize::Decoder::#decode_method( |
| __decoder, #opt_field_name #index, #decode_inner_method) { |
| ::std::result::Result::Ok(__res) => __res, |
| ::std::result::Result::Err(__err) => return ::std::result::Result::Err(__err), |
| } |
| } |
| } |
| |
| pub fn type_encodable_derive(mut s: synstructure::Structure<'_>) -> proc_macro2::TokenStream { |
| if !s.ast().generics.lifetimes().any(|lt| lt.lifetime.ident == "tcx") { |
| s.add_impl_generic(parse_quote! {'tcx}); |
| } |
| let encoder_ty = quote! { __E }; |
| s.add_impl_generic(parse_quote! {#encoder_ty: ::rustc_middle::ty::codec::TyEncoder<'tcx>}); |
| s.add_bounds(synstructure::AddBounds::Generics); |
| |
| encodable_body(s, encoder_ty, false) |
| } |
| |
| pub fn meta_encodable_derive(mut s: synstructure::Structure<'_>) -> proc_macro2::TokenStream { |
| if !s.ast().generics.lifetimes().any(|lt| lt.lifetime.ident == "tcx") { |
| s.add_impl_generic(parse_quote! {'tcx}); |
| } |
| s.add_impl_generic(parse_quote! { '__a }); |
| let encoder_ty = quote! { EncodeContext<'__a, 'tcx> }; |
| s.add_bounds(synstructure::AddBounds::Generics); |
| |
| encodable_body(s, encoder_ty, true) |
| } |
| |
| pub fn encodable_derive(mut s: synstructure::Structure<'_>) -> proc_macro2::TokenStream { |
| let encoder_ty = quote! { __E }; |
| s.add_impl_generic(parse_quote! { #encoder_ty: ::rustc_serialize::Encoder}); |
| s.add_bounds(synstructure::AddBounds::Generics); |
| |
| encodable_body(s, encoder_ty, false) |
| } |
| |
| fn encodable_body( |
| mut s: synstructure::Structure<'_>, |
| encoder_ty: TokenStream, |
| allow_unreachable_code: bool, |
| ) -> proc_macro2::TokenStream { |
| if let syn::Data::Union(_) = s.ast().data { |
| panic!("cannot derive on union") |
| } |
| |
| s.bind_with(|binding| { |
| // Handle the lack of a blanket reference impl. |
| if let syn::Type::Reference(_) = binding.ast().ty { |
| synstructure::BindStyle::Move |
| } else { |
| synstructure::BindStyle::Ref |
| } |
| }); |
| |
| let ty_name = s.ast().ident.to_string(); |
| let encode_body = match s.variants() { |
| [_] => { |
| let mut field_idx = 0usize; |
| let encode_inner = s.each_variant(|vi| { |
| vi.bindings() |
| .iter() |
| .map(|binding| { |
| let bind_ident = &binding.binding; |
| let field_name = binding |
| .ast() |
| .ident |
| .as_ref() |
| .map_or_else(|| field_idx.to_string(), |i| i.to_string()); |
| let result = quote! { |
| match ::rustc_serialize::Encoder::emit_struct_field( |
| __encoder, |
| #field_name, |
| #field_idx, |
| |__encoder| |
| ::rustc_serialize::Encodable::encode(#bind_ident, __encoder), |
| ) { |
| ::std::result::Result::Ok(()) => (), |
| ::std::result::Result::Err(__err) |
| => return ::std::result::Result::Err(__err), |
| } |
| }; |
| field_idx += 1; |
| result |
| }) |
| .collect::<TokenStream>() |
| }); |
| quote! { |
| ::rustc_serialize::Encoder::emit_struct(__encoder, #ty_name, #field_idx, |__encoder| { |
| ::std::result::Result::Ok(match *self { #encode_inner }) |
| }) |
| } |
| } |
| _ => { |
| let mut variant_idx = 0usize; |
| let encode_inner = s.each_variant(|vi| { |
| let variant_name = vi.ast().ident.to_string(); |
| let mut field_idx = 0usize; |
| |
| let encode_fields: TokenStream = vi |
| .bindings() |
| .iter() |
| .map(|binding| { |
| let bind_ident = &binding.binding; |
| let result = quote! { |
| match ::rustc_serialize::Encoder::emit_enum_variant_arg( |
| __encoder, |
| #field_idx, |
| |__encoder| |
| ::rustc_serialize::Encodable::encode(#bind_ident, __encoder), |
| ) { |
| ::std::result::Result::Ok(()) => (), |
| ::std::result::Result::Err(__err) |
| => return ::std::result::Result::Err(__err), |
| } |
| }; |
| field_idx += 1; |
| result |
| }) |
| .collect(); |
| |
| let result = quote! { ::rustc_serialize::Encoder::emit_enum_variant( |
| __encoder, |
| #variant_name, |
| #variant_idx, |
| #field_idx, |
| |__encoder| { ::std::result::Result::Ok({ #encode_fields }) } |
| ) }; |
| variant_idx += 1; |
| result |
| }); |
| quote! { |
| ::rustc_serialize::Encoder::emit_enum(__encoder, #ty_name, |__encoder| { |
| match *self { |
| #encode_inner |
| } |
| }) |
| } |
| } |
| }; |
| |
| let lints = if allow_unreachable_code { |
| quote! { #![allow(unreachable_code)] } |
| } else { |
| quote! {} |
| }; |
| |
| s.bound_impl( |
| quote!(::rustc_serialize::Encodable<#encoder_ty>), |
| quote! { |
| fn encode( |
| &self, |
| __encoder: &mut #encoder_ty, |
| ) -> ::std::result::Result<(), <#encoder_ty as ::rustc_serialize::Encoder>::Error> { |
| #lints |
| #encode_body |
| } |
| }, |
| ) |
| } |