style_traits/
dom.rs

1/* This Source Code Form is subject to the terms of the Mozilla Public
2 * License, v. 2.0. If a copy of the MPL was not distributed with this
3 * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
4
5//! Types used to access the DOM from style calculation.
6
7/// An opaque handle to a node, which, unlike UnsafeNode, cannot be transformed
8/// back into a non-opaque representation. The only safe operation that can be
9/// performed on this node is to compare it to another opaque handle or to another
10/// OpaqueNode.
11///
12/// Layout and Graphics use this to safely represent nodes for comparison purposes.
13/// Because the script task's GC does not trace layout, node data cannot be safely stored in layout
14/// data structures. Also, layout code tends to be faster when the DOM is not being accessed, for
15/// locality reasons. Using `OpaqueNode` enforces this invariant.
16#[derive(Clone, Copy, Debug, Eq, Hash, MallocSizeOf, PartialEq)]
17#[cfg_attr(feature = "servo", derive(Deserialize, Serialize))]
18pub struct OpaqueNode(pub usize);
19
20impl OpaqueNode {
21    /// Returns the address of this node, for debugging purposes.
22    #[inline]
23    pub fn id(&self) -> usize {
24        self.0
25    }
26}
style_traits/dom.rs

style_traits/
dom.rs
