108 lines
3.0 KiB
Rust
108 lines
3.0 KiB
Rust
use {syn, quote};
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pub fn impl_encodable(ast: &syn::DeriveInput) -> quote::Tokens {
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let body = match ast.data {
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syn::Data::Struct(ref s) => s,
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_ => panic!("#[derive(RlpEncodable)] is only defined for structs."),
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};
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let stmts: Vec<_> = body.fields.iter().enumerate().map(encodable_field_map).collect();
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let name = &ast.ident;
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let stmts_len = stmts.len();
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let stmts_len = quote! { #stmts_len };
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let dummy_const: syn::Ident = format!("_IMPL_RLP_ENCODABLE_FOR_{}", name).into();
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let impl_block = quote! {
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impl rlp::Encodable for #name {
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fn rlp_append(&self, stream: &mut rlp::RlpStream) {
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stream.begin_list(#stmts_len);
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#(#stmts)*
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}
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}
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};
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quote! {
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#[allow(non_upper_case_globals, unused_attributes, unused_qualifications)]
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const #dummy_const: () = {
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extern crate rlp;
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#impl_block
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};
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}
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}
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pub fn impl_encodable_wrapper(ast: &syn::DeriveInput) -> quote::Tokens {
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let body = match ast.data {
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syn::Data::Struct(ref s) => s,
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_ => panic!("#[derive(RlpEncodableWrapper)] is only defined for structs."),
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};
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let stmt = {
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let fields: Vec<_> = body.fields.iter().collect();
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if fields.len() == 1 {
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let field = fields.first().expect("fields.len() == 1; qed");
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encodable_field(0, field)
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} else {
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panic!("#[derive(RlpEncodableWrapper)] is only defined for structs with one field.")
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}
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};
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let name = &ast.ident;
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let dummy_const: syn::Ident = format!("_IMPL_RLP_ENCODABLE_FOR_{}", name).into();
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let impl_block = quote! {
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impl rlp::Encodable for #name {
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fn rlp_append(&self, stream: &mut rlp::RlpStream) {
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#stmt
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}
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}
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};
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quote! {
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#[allow(non_upper_case_globals, unused_attributes, unused_qualifications)]
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const #dummy_const: () = {
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extern crate rlp;
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#impl_block
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};
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}
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}
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fn encodable_field_map(tuple: (usize, &syn::Field)) -> quote::Tokens {
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encodable_field(tuple.0, tuple.1)
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}
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fn encodable_field(index: usize, field: &syn::Field) -> quote::Tokens {
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let ident = match field.ident {
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Some(ref ident) => quote! { #ident },
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None => {
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let index: syn::Index = index.into();
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quote! { #index }
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}
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};
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let id = quote! { self.#ident };
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match field.ty {
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syn::Type::Path(ref path) => {
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let top_segment = path.path.segments.first().expect("there must be at least 1 segment");
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let ident = &top_segment.value().ident;
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if &ident.to_string() == "Vec" {
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let inner_ident = match top_segment.value().arguments {
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syn::PathArguments::AngleBracketed(ref angle) => {
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let ty = angle.args.first().expect("Vec has only one angle bracketed type; qed");
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match **ty.value() {
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syn::GenericArgument::Type(syn::Type::Path(ref path)) => &path.path.segments.first().expect("there must be at least 1 segment").value().ident,
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_ => panic!("rlp_derive not supported"),
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}
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},
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_ => unreachable!("Vec has only one angle bracketed type; qed"),
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};
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quote! { stream.append_list::<#inner_ident, _>(&#id); }
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} else {
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quote! { stream.append(&#id); }
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}
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},
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_ => panic!("rlp_derive not supported"),
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}
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}
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