773 lines
21 KiB
Rust
773 lines
21 KiB
Rust
use std::collections::HashSet;
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use syntax::ast::{
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Ident,
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MetaItem,
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Item,
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Expr,
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StructDef,
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EnumDef,
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};
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use syntax::ast;
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use syntax::codemap::Span;
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use syntax::ext::base::ExtCtxt;
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use syntax::ext::build::AstBuilder;
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use syntax::ptr::P;
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use aster;
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use field;
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pub fn expand_derive_deserialize(
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cx: &mut ExtCtxt,
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span: Span,
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_mitem: &MetaItem,
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item: &Item,
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push: &mut FnMut(P<ast::Item>)
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) {
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let builder = aster::AstBuilder::new().span(span);
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let generics = match item.node {
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ast::ItemStruct(_, ref generics) => generics,
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ast::ItemEnum(_, ref generics) => generics,
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_ => cx.bug("expected ItemStruct or ItemEnum in #[derive(Deserialize)]")
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};
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let impl_generics = builder.from_generics(generics.clone())
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.add_ty_param_bound(
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builder.path().global().ids(&["serde", "de", "Deserialize"]).build()
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)
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.build();
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let ty = builder.ty().path()
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.segment(item.ident).with_generics(impl_generics.clone()).build()
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.build();
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let body = deserialize_body(
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cx,
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&builder,
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item,
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&impl_generics,
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ty.clone(),
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);
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let where_clause = &impl_generics.where_clause;
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let impl_item = quote_item!(cx,
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#[automatically_derived]
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impl $impl_generics ::serde::de::Deserialize for $ty $where_clause {
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fn deserialize<__D>(deserializer: &mut __D) -> ::std::result::Result<$ty, __D::Error>
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where __D: ::serde::de::Deserializer,
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{
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$body
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}
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}
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).unwrap();
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push(impl_item)
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}
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fn deserialize_body(
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cx: &ExtCtxt,
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builder: &aster::AstBuilder,
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item: &Item,
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impl_generics: &ast::Generics,
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ty: P<ast::Ty>,
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) -> P<ast::Expr> {
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match item.node {
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ast::ItemStruct(ref struct_def, _) => {
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deserialize_item_struct(
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cx,
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builder,
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item,
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impl_generics,
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ty,
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struct_def,
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)
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}
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ast::ItemEnum(ref enum_def, _) => {
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deserialize_item_enum(
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cx,
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builder,
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item.ident,
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impl_generics,
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ty,
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enum_def,
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)
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}
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_ => cx.bug("expected ItemStruct or ItemEnum in #[derive(Deserialize)]")
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}
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}
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fn deserialize_item_struct(
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cx: &ExtCtxt,
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builder: &aster::AstBuilder,
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item: &Item,
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impl_generics: &ast::Generics,
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ty: P<ast::Ty>,
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struct_def: &ast::StructDef,
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) -> P<ast::Expr> {
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let mut named_fields = vec![];
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let mut unnamed_fields = 0;
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for field in struct_def.fields.iter() {
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match field.node.kind {
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ast::NamedField(name, _) => { named_fields.push(name); }
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ast::UnnamedField(_) => { unnamed_fields += 1; }
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}
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}
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match (named_fields.is_empty(), unnamed_fields == 0) {
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(true, true) => {
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deserialize_unit_struct(
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cx,
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&builder,
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item.ident,
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)
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}
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(true, false) => {
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deserialize_tuple_struct(
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cx,
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&builder,
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item.ident,
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impl_generics,
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ty,
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unnamed_fields,
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)
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}
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(false, true) => {
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deserialize_struct(
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cx,
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&builder,
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item.ident,
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impl_generics,
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ty,
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struct_def,
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)
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}
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(false, false) => {
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cx.bug("struct has named and unnamed fields")
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}
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}
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}
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// Build `__Visitor<A, B, ...>(PhantomData<A>, PhantomData<B>, ...)`
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fn deserialize_visitor(
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builder: &aster::AstBuilder,
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trait_generics: &ast::Generics,
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) -> (P<ast::Item>, P<ast::Ty>, P<ast::Expr>) {
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if trait_generics.ty_params.is_empty() {
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(
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builder.item().tuple_struct("__Visitor").build(),
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builder.ty().id("__Visitor"),
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builder.expr().id("__Visitor"),
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)
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} else {
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(
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builder.item().tuple_struct("__Visitor")
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.generics().with(trait_generics.clone()).build()
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.with_tys(
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trait_generics.ty_params.iter().map(|ty_param| {
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builder.ty().phantom_data().id(ty_param.ident)
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})
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)
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.build(),
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builder.ty().path()
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.segment("__Visitor").with_generics(trait_generics.clone()).build()
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.build(),
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builder.expr().call().id("__Visitor")
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.with_args(
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trait_generics.ty_params.iter().map(|_| {
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builder.expr().phantom_data()
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})
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)
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.build(),
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)
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}
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}
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fn deserialize_unit_struct(
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cx: &ExtCtxt,
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builder: &aster::AstBuilder,
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type_ident: Ident,
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) -> P<ast::Expr> {
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let type_name = builder.expr().str(type_ident);
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quote_expr!(cx, {
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struct __Visitor;
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impl ::serde::de::Visitor for __Visitor {
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type Value = $type_ident;
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#[inline]
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fn visit_unit<E>(&mut self) -> ::std::result::Result<$type_ident, E>
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where E: ::serde::de::Error,
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{
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Ok($type_ident)
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}
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#[inline]
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fn visit_seq<V>(&mut self, mut visitor: V) -> ::std::result::Result<$type_ident, V::Error>
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where V: ::serde::de::SeqVisitor,
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{
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try!(visitor.end());
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self.visit_unit()
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}
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}
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deserializer.visit_named_unit($type_name, __Visitor)
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})
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}
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fn deserialize_tuple_struct(
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cx: &ExtCtxt,
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builder: &aster::AstBuilder,
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type_ident: Ident,
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impl_generics: &ast::Generics,
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ty: P<ast::Ty>,
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fields: usize,
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) -> P<ast::Expr> {
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let where_clause = &impl_generics.where_clause;
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let (visitor_item, visitor_ty, visitor_expr) = deserialize_visitor(
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builder,
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impl_generics,
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);
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let visit_seq_expr = deserialize_seq(
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cx,
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builder,
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builder.path().id(type_ident).build(),
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fields,
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);
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let type_name = builder.expr().str(type_ident);
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quote_expr!(cx, {
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$visitor_item
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impl $impl_generics ::serde::de::Visitor for $visitor_ty $where_clause {
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type Value = $ty;
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fn visit_seq<__V>(&mut self, mut visitor: __V) -> ::std::result::Result<$ty, __V::Error>
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where __V: ::serde::de::SeqVisitor,
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{
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$visit_seq_expr
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}
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}
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deserializer.visit_named_seq($type_name, $visitor_expr)
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})
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}
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fn deserialize_seq(
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cx: &ExtCtxt,
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builder: &aster::AstBuilder,
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struct_path: ast::Path,
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fields: usize,
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) -> P<ast::Expr> {
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let let_values: Vec<P<ast::Stmt>> = (0 .. fields)
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.map(|i| {
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let name = builder.id(format!("__field{}", i));
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quote_stmt!(cx,
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let $name = match try!(visitor.visit()) {
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Some(value) => value,
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None => {
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return Err(::serde::de::Error::end_of_stream_error());
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}
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};
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).unwrap()
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})
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.collect();
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let result = builder.expr().call()
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.build_path(struct_path)
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.with_args((0 .. fields).map(|i| builder.expr().id(format!("__field{}", i))))
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.build();
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quote_expr!(cx, {
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$let_values
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try!(visitor.end());
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Ok($result)
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})
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}
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fn deserialize_struct(
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cx: &ExtCtxt,
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builder: &aster::AstBuilder,
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type_ident: Ident,
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impl_generics: &ast::Generics,
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ty: P<ast::Ty>,
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struct_def: &StructDef,
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) -> P<ast::Expr> {
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let where_clause = &impl_generics.where_clause;
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let (visitor_item, visitor_ty, visitor_expr) = deserialize_visitor(
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builder,
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impl_generics,
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);
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let (field_visitor, visit_map_expr) = deserialize_struct_visitor(
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cx,
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builder,
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struct_def,
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builder.path().id(type_ident).build(),
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);
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let type_name = builder.expr().str(type_ident);
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quote_expr!(cx, {
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$field_visitor
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$visitor_item
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impl $impl_generics ::serde::de::Visitor for $visitor_ty $where_clause {
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type Value = $ty;
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#[inline]
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fn visit_map<__V>(&mut self, mut visitor: __V) -> ::std::result::Result<$ty, __V::Error>
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where __V: ::serde::de::MapVisitor,
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{
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$visit_map_expr
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}
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}
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deserializer.visit_named_map($type_name, $visitor_expr)
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})
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}
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fn deserialize_item_enum(
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cx: &ExtCtxt,
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builder: &aster::AstBuilder,
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type_ident: Ident,
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impl_generics: &ast::Generics,
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ty: P<ast::Ty>,
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enum_def: &EnumDef,
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) -> P<ast::Expr> {
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let where_clause = &impl_generics.where_clause;
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let type_name = builder.expr().str(type_ident);
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let variant_visitor = deserialize_field_visitor(
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cx,
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builder,
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enum_def.variants.iter()
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.map(|variant|
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field::FieldLit::Global(builder.expr().str(variant.node.name)))
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.collect()
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);
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// Match arms to extract a variant from a string
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let variant_arms: Vec<_> = enum_def.variants.iter()
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.enumerate()
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.map(|(i, variant)| {
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let variant_name = builder.pat().enum_()
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.id("__Field").id(format!("__field{}", i)).build()
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.build();
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let expr = deserialize_variant(
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cx,
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builder,
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type_ident,
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impl_generics,
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ty.clone(),
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variant,
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);
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quote_arm!(cx, $variant_name => { $expr })
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})
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.collect();
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let (visitor_item, visitor_ty, visitor_expr) = deserialize_visitor(
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builder,
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impl_generics,
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);
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quote_expr!(cx, {
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$variant_visitor
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$visitor_item
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impl $impl_generics ::serde::de::EnumVisitor for $visitor_ty $where_clause {
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type Value = $ty;
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fn visit<__V>(&mut self, mut visitor: __V) -> ::std::result::Result<$ty, __V::Error>
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where __V: ::serde::de::VariantVisitor,
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{
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match try!(visitor.visit_variant()) {
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$variant_arms
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}
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}
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}
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deserializer.visit_enum($type_name, $visitor_expr)
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})
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}
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fn deserialize_variant(
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cx: &ExtCtxt,
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builder: &aster::AstBuilder,
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type_ident: Ident,
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generics: &ast::Generics,
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ty: P<ast::Ty>,
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variant: &ast::Variant,
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) -> P<ast::Expr> {
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let variant_ident = variant.node.name;
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match variant.node.kind {
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ast::TupleVariantKind(ref args) if args.is_empty() => {
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quote_expr!(cx, {
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try!(visitor.visit_unit());
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Ok($type_ident::$variant_ident)
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})
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}
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ast::TupleVariantKind(ref args) => {
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deserialize_tuple_variant(
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cx,
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builder,
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type_ident,
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variant_ident,
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generics,
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ty,
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args.len(),
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)
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}
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ast::StructVariantKind(ref struct_def) => {
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deserialize_struct_variant(
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cx,
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builder,
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type_ident,
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variant_ident,
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generics,
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ty,
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struct_def,
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)
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}
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}
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}
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fn deserialize_tuple_variant(
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cx: &ExtCtxt,
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builder: &aster::AstBuilder,
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type_ident: ast::Ident,
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variant_ident: ast::Ident,
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generics: &ast::Generics,
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ty: P<ast::Ty>,
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fields: usize,
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) -> P<ast::Expr> {
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let where_clause = &generics.where_clause;
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let (visitor_item, visitor_ty, visitor_expr) = deserialize_visitor(
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builder,
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generics,
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);
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let visit_seq_expr = deserialize_seq(
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cx,
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builder,
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builder.path().id(type_ident).id(variant_ident).build(),
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fields,
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);
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quote_expr!(cx, {
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$visitor_item
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impl $generics ::serde::de::Visitor for $visitor_ty $where_clause {
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type Value = $ty;
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fn visit_seq<__V>(&mut self, mut visitor: __V) -> ::std::result::Result<$ty, __V::Error>
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where __V: ::serde::de::SeqVisitor,
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{
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$visit_seq_expr
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}
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}
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visitor.visit_seq($visitor_expr)
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})
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}
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fn deserialize_struct_variant(
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cx: &ExtCtxt,
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builder: &aster::AstBuilder,
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type_ident: ast::Ident,
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variant_ident: ast::Ident,
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generics: &ast::Generics,
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ty: P<ast::Ty>,
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struct_def: &ast::StructDef,
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) -> P<ast::Expr> {
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let where_clause = &generics.where_clause;
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let (field_visitor, field_expr) = deserialize_struct_visitor(
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cx,
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builder,
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struct_def,
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builder.path().id(type_ident).id(variant_ident).build(),
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);
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let (visitor_item, visitor_ty, visitor_expr) = deserialize_visitor(
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builder,
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generics,
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);
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quote_expr!(cx, {
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$field_visitor
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|
$visitor_item
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impl $generics ::serde::de::Visitor for $visitor_ty $where_clause {
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type Value = $ty;
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fn visit_map<__V>(&mut self, mut visitor: __V) -> ::std::result::Result<$ty, __V::Error>
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where __V: ::serde::de::MapVisitor,
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{
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$field_expr
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}
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}
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visitor.visit_map($visitor_expr)
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})
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}
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fn deserialize_field_visitor(
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cx: &ExtCtxt,
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builder: &aster::AstBuilder,
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field_exprs: Vec<field::FieldLit>,
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) -> Vec<P<ast::Item>> {
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// Create the field names for the fields.
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let field_idents: Vec<ast::Ident> = (0 .. field_exprs.len())
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.map(|i| builder.id(format!("__field{}", i)))
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.collect();
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let field_enum = builder.item()
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.attr().allow(&["non_camel_case_types"])
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.enum_("__Field")
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.with_variants(
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field_idents.iter().map(|field_ident| {
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builder.variant(field_ident).tuple().build()
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})
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)
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.build();
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let fmts = field_exprs.iter()
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.fold(HashSet::new(), |mut set, field_expr|
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match field_expr {
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&field::FieldLit::Format{ref formats, default: _} => {
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for (fmt, _) in formats.iter() {
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set.insert(fmt.clone());
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};
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set
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},
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_ => set
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});
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|
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// Match arms to extract a field from a string
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let default_field_arms: Vec<_> = field_idents.iter()
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.zip(field_exprs.iter())
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.map(|(field_ident, field_expr)| {
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match field_expr {
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&field::FieldLit::Global(ref expr) =>
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quote_arm!(cx, $expr => { Ok(__Field::$field_ident) }),
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&field::FieldLit::Format{formats: _, ref default} =>
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quote_arm!(cx, $default => { Ok(__Field::$field_ident)})
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}
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|
})
|
|
.collect();
|
|
|
|
let body = if fmts.is_empty() {
|
|
quote_expr!(cx,
|
|
match value {
|
|
$default_field_arms,
|
|
_ => Err(::serde::de::Error::unknown_field_error(value)),
|
|
})
|
|
} else {
|
|
let field_arms : Vec<_> = fmts.iter()
|
|
.map(|fmt| {
|
|
field_idents.iter()
|
|
.zip(field_exprs.iter())
|
|
.map(|(field_ident, field_expr)| {
|
|
match field_expr {
|
|
&field::FieldLit::Global(ref expr) =>
|
|
quote_arm!(cx,
|
|
$expr => { Ok(__Field::$field_ident) }),
|
|
&field::FieldLit::Format{ref formats, ref default} => {
|
|
let expr = formats.get(fmt).unwrap_or(default);
|
|
quote_arm!(cx,
|
|
$expr => { Ok(__Field::$field_ident) })}}
|
|
})
|
|
.collect::<Vec<_>>()
|
|
})
|
|
.collect();
|
|
|
|
let fmt_matches : Vec<_> = fmts.iter()
|
|
.zip(field_arms.iter())
|
|
.map(|(ref fmt, ref arms)| {
|
|
quote_arm!(cx, $fmt => {
|
|
match value {
|
|
$arms,
|
|
_ => {
|
|
Err(::serde::de::Error::unknown_field_error(value))
|
|
}
|
|
}})
|
|
})
|
|
.collect();
|
|
|
|
quote_expr!(cx,
|
|
match D::format() {
|
|
$fmt_matches,
|
|
_ => match value {
|
|
$default_field_arms,
|
|
_ => Err(::serde::de::Error::unknown_field_error(value)),
|
|
}
|
|
})
|
|
};
|
|
|
|
vec![
|
|
field_enum,
|
|
|
|
quote_item!(cx,
|
|
impl ::serde::de::Deserialize for __Field {
|
|
#[inline]
|
|
fn deserialize<D>(deserializer: &mut D) -> ::std::result::Result<__Field, D::Error>
|
|
where D: ::serde::de::Deserializer,
|
|
{
|
|
use std::marker::PhantomData;
|
|
|
|
struct __FieldVisitor<D> {
|
|
phantom: PhantomData<D>
|
|
}
|
|
|
|
impl<D> ::serde::de::Visitor for __FieldVisitor<D>
|
|
where D: ::serde::de::Deserializer
|
|
{
|
|
type Value = __Field;
|
|
|
|
fn visit_str<E>(&mut self, value: &str) -> ::std::result::Result<__Field, E>
|
|
where E: ::serde::de::Error,
|
|
{
|
|
$body
|
|
}
|
|
}
|
|
|
|
deserializer.visit(
|
|
__FieldVisitor::<D>{ phantom: PhantomData })
|
|
}
|
|
}
|
|
).unwrap(),
|
|
]
|
|
}
|
|
|
|
fn deserialize_struct_visitor(
|
|
cx: &ExtCtxt,
|
|
builder: &aster::AstBuilder,
|
|
struct_def: &ast::StructDef,
|
|
struct_path: ast::Path,
|
|
) -> (Vec<P<ast::Item>>, P<ast::Expr>) {
|
|
let field_visitor = deserialize_field_visitor(
|
|
cx,
|
|
builder,
|
|
field::struct_field_strs(cx, builder, struct_def),
|
|
);
|
|
|
|
let visit_map_expr = deserialize_map(
|
|
cx,
|
|
builder,
|
|
struct_path,
|
|
struct_def,
|
|
);
|
|
|
|
(field_visitor, visit_map_expr)
|
|
}
|
|
|
|
fn deserialize_map(
|
|
cx: &ExtCtxt,
|
|
builder: &aster::AstBuilder,
|
|
struct_path: ast::Path,
|
|
struct_def: &StructDef,
|
|
) -> P<ast::Expr> {
|
|
// Create the field names for the fields.
|
|
let field_names: Vec<ast::Ident> = (0 .. struct_def.fields.len())
|
|
.map(|i| builder.id(format!("__field{}", i)))
|
|
.collect();
|
|
|
|
// Declare each field.
|
|
let let_values: Vec<P<ast::Stmt>> = field_names.iter()
|
|
.map(|field_name| quote_stmt!(cx, let mut $field_name = None;).unwrap())
|
|
.collect();
|
|
|
|
// Match arms to extract a value for a field.
|
|
let value_arms: Vec<ast::Arm> = field_names.iter()
|
|
.map(|field_name| {
|
|
quote_arm!(cx,
|
|
__Field::$field_name => {
|
|
$field_name = Some(try!(visitor.visit_value()));
|
|
}
|
|
)
|
|
})
|
|
.collect();
|
|
|
|
let extract_values: Vec<P<ast::Stmt>> = field_names.iter()
|
|
.zip(struct_def.fields.iter())
|
|
.map(|(field_name, field)| {
|
|
let rename = field::field_rename(builder, field);
|
|
let name_str = match (rename, field.node.kind) {
|
|
(field::Rename::Global(rename), _)
|
|
=> builder.expr().build_lit(P(rename.clone())),
|
|
(field::Rename::None, ast::NamedField(name, _))
|
|
=> builder.expr().str(name),
|
|
(field::Rename::None, ast::UnnamedField(_))
|
|
=> panic!("struct contains unnamed fields"),
|
|
(field::Rename::Format(renames), _)
|
|
=> builder.expr().str("fixme"),
|
|
};
|
|
|
|
let missing_expr = if field::default_value(field) {
|
|
quote_expr!(cx, ::std::default::Default::default())
|
|
} else {
|
|
quote_expr!(cx, try!(visitor.missing_field($name_str)))
|
|
};
|
|
|
|
quote_stmt!(cx,
|
|
let $field_name = match $field_name {
|
|
Some($field_name) => $field_name,
|
|
None => $missing_expr,
|
|
};
|
|
).unwrap()
|
|
})
|
|
.collect();
|
|
|
|
let result = builder.expr().struct_path(struct_path)
|
|
.with_id_exprs(
|
|
struct_def.fields.iter()
|
|
.zip(field_names.iter())
|
|
.map(|(field, field_name)| {
|
|
(
|
|
match field.node.kind {
|
|
ast::NamedField(name, _) => name.clone(),
|
|
ast::UnnamedField(_) => panic!("struct contains unnamed fields"),
|
|
},
|
|
builder.expr().id(field_name),
|
|
)
|
|
})
|
|
)
|
|
.build();
|
|
|
|
quote_expr!(cx, {
|
|
$let_values
|
|
|
|
while let Some(key) = try!(visitor.visit_key()) {
|
|
match key {
|
|
$value_arms
|
|
}
|
|
}
|
|
|
|
$extract_values
|
|
|
|
try!(visitor.end());
|
|
|
|
Ok($result)
|
|
})
|
|
}
|