diff options
Diffstat (limited to 'compiler/rustc_builtin_macros/src/deriving/decodable.rs')
| -rw-r--r-- | compiler/rustc_builtin_macros/src/deriving/decodable.rs | 215 |
1 files changed, 0 insertions, 215 deletions
diff --git a/compiler/rustc_builtin_macros/src/deriving/decodable.rs b/compiler/rustc_builtin_macros/src/deriving/decodable.rs deleted file mode 100644 index 6348560496e..00000000000 --- a/compiler/rustc_builtin_macros/src/deriving/decodable.rs +++ /dev/null @@ -1,215 +0,0 @@ -//! The compiler code necessary for `#[derive(RustcDecodable)]`. See encodable.rs for more. - -use rustc_ast::ptr::P; -use rustc_ast::{self as ast, Expr, MetaItem, Mutability}; -use rustc_expand::base::{Annotatable, ExtCtxt}; -use rustc_span::{Ident, Span, Symbol, sym}; -use thin_vec::{ThinVec, thin_vec}; - -use crate::deriving::generic::ty::*; -use crate::deriving::generic::*; -use crate::deriving::pathvec_std; - -pub(crate) fn expand_deriving_rustc_decodable( - cx: &ExtCtxt<'_>, - span: Span, - mitem: &MetaItem, - item: &Annotatable, - push: &mut dyn FnMut(Annotatable), - is_const: bool, -) { - let krate = sym::rustc_serialize; - let typaram = sym::__D; - - let trait_def = TraitDef { - span, - path: Path::new_(vec![krate, sym::Decodable], vec![], PathKind::Global), - skip_path_as_bound: false, - needs_copy_as_bound_if_packed: true, - additional_bounds: Vec::new(), - supports_unions: false, - methods: vec![MethodDef { - name: sym::decode, - generics: Bounds { - bounds: vec![(typaram, vec![Path::new_( - vec![krate, sym::Decoder], - vec![], - PathKind::Global, - )])], - }, - explicit_self: false, - nonself_args: vec![( - Ref(Box::new(Path(Path::new_local(typaram))), Mutability::Mut), - sym::d, - )], - ret_ty: Path(Path::new_( - pathvec_std!(result::Result), - vec![ - Box::new(Self_), - Box::new(Path(Path::new_(vec![typaram, sym::Error], vec![], PathKind::Local))), - ], - PathKind::Std, - )), - attributes: ast::AttrVec::new(), - fieldless_variants_strategy: FieldlessVariantsStrategy::Default, - combine_substructure: combine_substructure(Box::new(|a, b, c| { - decodable_substructure(a, b, c, krate) - })), - }], - associated_types: Vec::new(), - is_const, - }; - - trait_def.expand(cx, mitem, item, push) -} - -fn decodable_substructure( - cx: &ExtCtxt<'_>, - trait_span: Span, - substr: &Substructure<'_>, - krate: Symbol, -) -> BlockOrExpr { - let decoder = substr.nonselflike_args[0].clone(); - let recurse = vec![ - Ident::new(krate, trait_span), - Ident::new(sym::Decodable, trait_span), - Ident::new(sym::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 = Ident::new(sym::_d, trait_span); - let blkdecoder = cx.expr_ident(trait_span, blkarg); - - let expr = match substr.fields { - StaticStruct(_, summary) => { - let nfields = match summary { - Unnamed(fields, _) => fields.len(), - Named(fields) => fields.len(), - }; - let fn_read_struct_field_path: Vec<_> = - cx.def_site_path(&[sym::rustc_serialize, sym::Decoder, sym::read_struct_field]); - - 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_call_global(span, fn_read_struct_field_path.clone(), thin_vec![ - blkdecoder.clone(), - cx.expr_str(span, name), - cx.expr_usize(span, field), - exprdecode.clone(), - ]), - ) - }); - let result = cx.expr_ok(trait_span, result); - let fn_read_struct_path: Vec<_> = - cx.def_site_path(&[sym::rustc_serialize, sym::Decoder, sym::read_struct]); - - cx.expr_call_global(trait_span, fn_read_struct_path, thin_vec![ - decoder, - cx.expr_str(trait_span, substr.type_ident.name), - cx.expr_usize(trait_span, nfields), - cx.lambda1(trait_span, result, blkarg), - ]) - } - StaticEnum(_, fields) => { - let variant = Ident::new(sym::i, trait_span); - - let mut arms = ThinVec::with_capacity(fields.len() + 1); - let mut variants = ThinVec::with_capacity(fields.len()); - - let fn_read_enum_variant_arg_path: Vec<_> = - cx.def_site_path(&[sym::rustc_serialize, sym::Decoder, sym::read_enum_variant_arg]); - - 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_call_global( - span, - fn_read_enum_variant_arg_path.clone(), - thin_vec![blkdecoder.clone(), 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_array_ref = cx.expr_array_ref(trait_span, variants); - let fn_read_enum_variant_path: Vec<_> = - cx.def_site_path(&[sym::rustc_serialize, sym::Decoder, sym::read_enum_variant]); - let result = cx.expr_call_global(trait_span, fn_read_enum_variant_path, thin_vec![ - blkdecoder, - variant_array_ref, - lambda - ]); - let fn_read_enum_path: Vec<_> = - cx.def_site_path(&[sym::rustc_serialize, sym::Decoder, sym::read_enum]); - - cx.expr_call_global(trait_span, fn_read_enum_path, thin_vec![ - decoder, - cx.expr_str(trait_span, substr.type_ident.name), - cx.lambda1(trait_span, result, blkarg), - ]) - } - _ => cx.dcx().bug("expected StaticEnum or StaticStruct in derive(Decodable)"), - }; - BlockOrExpr::new_expr(expr) -} - -/// 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: &ExtCtxt<'_>, - trait_span: Span, - outer_pat_path: ast::Path, - fields: &StaticFields, - mut getarg: F, -) -> P<Expr> -where - F: FnMut(&ExtCtxt<'_>, Span, Symbol, usize) -> P<Expr>, -{ - match fields { - Unnamed(fields, is_tuple) => { - let path_expr = cx.expr_path(outer_pat_path); - if matches!(is_tuple, IsTuple::No) { - 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(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) - } - } -} |