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Diffstat (limited to 'src/libsyntax_ext/deriving/decodable.rs')
| -rw-r--r-- | src/libsyntax_ext/deriving/decodable.rs | 225 |
1 files changed, 0 insertions, 225 deletions
diff --git a/src/libsyntax_ext/deriving/decodable.rs b/src/libsyntax_ext/deriving/decodable.rs deleted file mode 100644 index 7f21440d49a..00000000000 --- a/src/libsyntax_ext/deriving/decodable.rs +++ /dev/null @@ -1,225 +0,0 @@ -//! The compiler code necessary for `#[derive(RustcDecodable)]`. See encodable.rs for more. - -use crate::deriving::generic::ty::*; -use crate::deriving::generic::*; -use crate::deriving::pathvec_std; - -use syntax::ast; -use syntax::ast::{Expr, MetaItem, Mutability}; -use syntax::ptr::P; -use syntax::symbol::Symbol; -use syntax_expand::base::{Annotatable, ExtCtxt}; -use syntax_pos::Span; - -pub fn expand_deriving_rustc_decodable( - cx: &mut ExtCtxt<'_>, - span: Span, - mitem: &MetaItem, - item: &Annotatable, - push: &mut dyn FnMut(Annotatable), -) { - let krate = "rustc_serialize"; - let typaram = "__D"; - - let trait_def = TraitDef { - span, - attributes: Vec::new(), - path: Path::new_(vec![krate, "Decodable"], None, vec![], PathKind::Global), - additional_bounds: Vec::new(), - generics: LifetimeBounds::empty(), - is_unsafe: false, - supports_unions: false, - methods: vec![MethodDef { - name: "decode", - generics: LifetimeBounds { - lifetimes: Vec::new(), - bounds: vec![( - typaram, - vec![Path::new_(vec![krate, "Decoder"], None, vec![], PathKind::Global)], - )], - }, - explicit_self: None, - args: vec![( - Ptr(Box::new(Literal(Path::new_local(typaram))), Borrowed(None, Mutability::Mut)), - "d", - )], - ret_ty: Literal(Path::new_( - pathvec_std!(cx, result::Result), - None, - vec![ - Box::new(Self_), - Box::new(Literal(Path::new_( - vec![typaram, "Error"], - None, - vec![], - PathKind::Local, - ))), - ], - PathKind::Std, - )), - attributes: Vec::new(), - is_unsafe: false, - unify_fieldless_variants: false, - combine_substructure: combine_substructure(Box::new(|a, b, c| { - decodable_substructure(a, b, c, krate) - })), - }], - associated_types: Vec::new(), - }; - - trait_def.expand(cx, mitem, item, push) -} - -fn decodable_substructure( - cx: &mut ExtCtxt<'_>, - trait_span: Span, - substr: &Substructure<'_>, - krate: &str, -) -> P<Expr> { - let decoder = substr.nonself_args[0].clone(); - let recurse = vec![ - cx.ident_of(krate, trait_span), - cx.ident_of("Decodable", trait_span), - cx.ident_of("decode", trait_span), - ]; - let exprdecode = cx.expr_path(cx.path_global(trait_span, recurse)); - // throw an underscore in front to suppress unused variable warnings - let blkarg = cx.ident_of("_d", trait_span); - let blkdecoder = cx.expr_ident(trait_span, blkarg); - - return match *substr.fields { - StaticStruct(_, ref summary) => { - let nfields = match *summary { - Unnamed(ref fields, _) => fields.len(), - Named(ref fields) => fields.len(), - }; - let read_struct_field = cx.ident_of("read_struct_field", trait_span); - - let path = cx.path_ident(trait_span, substr.type_ident); - let result = - decode_static_fields(cx, trait_span, path, summary, |cx, span, name, field| { - cx.expr_try( - span, - cx.expr_method_call( - span, - blkdecoder.clone(), - read_struct_field, - vec![ - cx.expr_str(span, name), - cx.expr_usize(span, field), - exprdecode.clone(), - ], - ), - ) - }); - let result = cx.expr_ok(trait_span, result); - cx.expr_method_call( - trait_span, - decoder, - cx.ident_of("read_struct", trait_span), - vec![ - cx.expr_str(trait_span, substr.type_ident.name), - cx.expr_usize(trait_span, nfields), - cx.lambda1(trait_span, result, blkarg), - ], - ) - } - StaticEnum(_, ref fields) => { - let variant = cx.ident_of("i", trait_span); - - let mut arms = Vec::with_capacity(fields.len() + 1); - let mut variants = Vec::with_capacity(fields.len()); - let rvariant_arg = cx.ident_of("read_enum_variant_arg", trait_span); - - for (i, &(ident, v_span, ref parts)) in fields.iter().enumerate() { - variants.push(cx.expr_str(v_span, ident.name)); - - let path = cx.path(trait_span, vec![substr.type_ident, ident]); - let decoded = - decode_static_fields(cx, v_span, path, parts, |cx, span, _, field| { - let idx = cx.expr_usize(span, field); - cx.expr_try( - span, - cx.expr_method_call( - span, - blkdecoder.clone(), - rvariant_arg, - vec![idx, exprdecode.clone()], - ), - ) - }); - - arms.push(cx.arm(v_span, cx.pat_lit(v_span, cx.expr_usize(v_span, i)), decoded)); - } - - arms.push(cx.arm_unreachable(trait_span)); - - let result = cx.expr_ok( - trait_span, - cx.expr_match(trait_span, cx.expr_ident(trait_span, variant), arms), - ); - let lambda = cx.lambda(trait_span, vec![blkarg, variant], result); - let variant_vec = cx.expr_vec(trait_span, variants); - let variant_vec = cx.expr_addr_of(trait_span, variant_vec); - let result = cx.expr_method_call( - trait_span, - blkdecoder, - cx.ident_of("read_enum_variant", trait_span), - vec![variant_vec, lambda], - ); - cx.expr_method_call( - trait_span, - decoder, - cx.ident_of("read_enum", trait_span), - vec![ - cx.expr_str(trait_span, substr.type_ident.name), - cx.lambda1(trait_span, result, blkarg), - ], - ) - } - _ => cx.bug("expected StaticEnum or StaticStruct in derive(Decodable)"), - }; -} - -/// Creates a decoder for a single enum variant/struct: -/// - `outer_pat_path` is the path to this enum variant/struct -/// - `getarg` should retrieve the `usize`-th field with name `@str`. -fn decode_static_fields<F>( - cx: &mut ExtCtxt<'_>, - trait_span: Span, - outer_pat_path: ast::Path, - fields: &StaticFields, - mut getarg: F, -) -> P<Expr> -where - F: FnMut(&mut ExtCtxt<'_>, Span, Symbol, usize) -> P<Expr>, -{ - match *fields { - Unnamed(ref fields, is_tuple) => { - let path_expr = cx.expr_path(outer_pat_path); - if !is_tuple { - path_expr - } else { - let fields = fields - .iter() - .enumerate() - .map(|(i, &span)| getarg(cx, span, Symbol::intern(&format!("_field{}", i)), i)) - .collect(); - - cx.expr_call(trait_span, path_expr, fields) - } - } - Named(ref fields) => { - // use the field's span to get nicer error messages. - let fields = fields - .iter() - .enumerate() - .map(|(i, &(ident, span))| { - let arg = getarg(cx, span, ident.name, i); - cx.field_imm(span, ident, arg) - }) - .collect(); - cx.expr_struct(trait_span, outer_pat_path, fields) - } - } -} |