1 // Copyright 2014 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 use ast::{MetaItem, Item, Expr, MutMutable};
13 use ext::base::ExtCtxt;
14 use ext::build::AstBuilder;
15 use ext::deriving::generic::*;
16 use ext::deriving::generic::ty::*;
17 use parse::token::InternedString;
20 pub fn expand_deriving_hash<F>(cx: &mut ExtCtxt,
28 let path = Path::new_(vec!("std", "hash", "Hash"), None,
29 vec!(box Literal(Path::new_local("__S"))), true);
30 let generics = LifetimeBounds {
31 lifetimes: Vec::new(),
33 vec!(Path::new(vec!("std", "hash", "Writer")),
34 Path::new(vec!("std", "hash", "Hasher"))))),
36 let args = Path::new_local("__S");
37 let inline = cx.meta_word(span, InternedString::new("inline"));
38 let attrs = vec!(cx.attribute(span, inline));
39 let hash_trait_def = TraitDef {
41 attributes: Vec::new(),
43 additional_bounds: Vec::new(),
48 generics: LifetimeBounds::empty(),
49 explicit_self: borrowed_explicit_self(),
50 args: vec!(Ptr(box Literal(args), Borrowed(None, MutMutable))),
53 combine_substructure: combine_substructure(box |a, b, c| {
54 hash_substructure(a, b, c)
60 hash_trait_def.expand(cx, mitem, item, push);
63 fn hash_substructure(cx: &mut ExtCtxt, trait_span: Span, substr: &Substructure) -> P<Expr> {
64 let state_expr = match substr.nonself_args {
65 [ref state_expr] => state_expr,
66 _ => cx.span_bug(trait_span, "incorrect number of arguments in `derive(Hash)`")
68 let call_hash = |&: span, thing_expr| {
77 cx.expr_path(cx.path_global(span, strs))
79 let ref_thing = cx.expr_addr_of(span, thing_expr);
80 let expr = cx.expr_call(span, hash_path, vec!(ref_thing, state_expr.clone()));
83 let mut stmts = Vec::new();
85 let fields = match *substr.fields {
87 EnumMatching(index, variant, ref fs) => {
88 // Determine the discriminant. We will feed this value to the byte
89 // iteration function.
90 let discriminant = match variant.node.disr_expr {
91 Some(ref d) => d.clone(),
92 None => cx.expr_uint(trait_span, index)
95 stmts.push(call_hash(trait_span, discriminant));
99 _ => cx.span_bug(trait_span, "impossible substructure in `derive(Hash)`")
102 for &FieldInfo { ref self_, span, .. } in fields.iter() {
103 stmts.push(call_hash(span, self_.clone()));
106 cx.expr_block(cx.block(trait_span, stmts, None))