servo/components/script/mem.rs

36 lines
1.8 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/. */
//! Routines for handling measuring the memory usage of arbitrary DOM nodes.
use dom::bindings::codegen::InheritTypes::{DocumentCast, WindowCast, CharacterDataCast, NodeCast};
use dom::eventtarget::{EventTarget, EventTargetTypeId};
use dom::node::NodeTypeId;
use libc;
use util::mem::{HeapSizeOf, heap_size_of};
// This is equivalent to measuring a Box<T>, except that DOM objects lose their
// associated box in order to stash their pointers in a reserved slot of their
// JS reflector. It is assumed that the caller passes a pointer to the most-derived
// type that this pointer represents, or the actual heap usage of the pointee will
// be under-reported.
fn heap_size_of_self_and_children<T: HeapSizeOf>(obj: &T) -> usize {
heap_size_of(obj as *const T as *const libc::c_void) + obj.heap_size_of_children()
}
pub fn heap_size_of_eventtarget(target: &EventTarget) -> usize {
//TODO: add more specific matches for concrete element types as derive(HeapSizeOf) is
// added to each one.
match target.type_id() {
&EventTargetTypeId::Window =>
heap_size_of_self_and_children(WindowCast::to_ref(target).unwrap()),
&EventTargetTypeId::Node(NodeTypeId::CharacterData(_)) =>
heap_size_of_self_and_children(CharacterDataCast::to_ref(target).unwrap()),
&EventTargetTypeId::Node(NodeTypeId::Document) =>
heap_size_of_self_and_children(DocumentCast::to_ref(target).unwrap()),
&EventTargetTypeId::Node(_) =>
heap_size_of_self_and_children(NodeCast::to_ref(target).unwrap()),
_ => 0,
}
}