servo/components/plugins/heapsize.rs
2015-06-03 07:13:40 +05:30

58 lines
2.4 KiB
Rust

/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
use syntax::ext::base::{Annotatable, ExtCtxt};
use syntax::codemap::Span;
use syntax::ptr::P;
use syntax::ast::*;
use syntax::attr::AttrMetaMethods;
use syntax::ext::build::AstBuilder;
use syntax::ext::deriving::generic::*;
pub fn expand_heapsize(cx: &mut ExtCtxt, span: Span, mitem: &MetaItem,
item: Annotatable, push: &mut FnMut(Annotatable)) {
let trait_def = TraitDef {
span: span,
attributes: Vec::new(),
path: ty::Path::new(vec!("util", "mem", "HeapSizeOf")),
additional_bounds: Vec::new(),
generics: ty::LifetimeBounds::empty(),
methods: vec![
MethodDef {
name: "heap_size_of_children",
generics: ty::LifetimeBounds::empty(),
explicit_self: ty::borrowed_explicit_self(),
args: vec!(),
ret_ty: ty::Literal(ty::Path::new_local("usize")),
attributes: vec!(),
is_unsafe: false,
combine_substructure: combine_substructure(Box::new(heapsize_substructure))
}
],
associated_types: vec![],
};
trait_def.expand(cx, mitem, &item, push)
}
fn heapsize_substructure(cx: &mut ExtCtxt, trait_span: Span, substr: &Substructure) -> P<Expr> {
let fields = match *substr.fields {
Struct(ref fs) | EnumMatching(_, _, ref fs) => fs,
_ => cx.span_bug(trait_span, "impossible substructure in `heapsize`")
};
fields.iter().fold(cx.expr_usize(trait_span, 0),
|acc, ref item| {
if item.attrs.iter()
.find(|ref a| a.check_name("ignore_heap_size"))
.is_some() {
acc
} else {
cx.expr_binary(item.span, BiAdd, acc,
cx.expr_method_call(item.span,
item.self_.clone(),
substr.method_ident,
Vec::new()))
}
})
}