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/* 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 https://mozilla.org/MPL/2.0/. */
//! Types used to access the DOM from style calculation.
/// An opaque handle to a node, which, unlike UnsafeNode, cannot be transformed
/// back into a non-opaque representation. The only safe operation that can be
/// performed on this node is to compare it to another opaque handle or to another
/// OpaqueNode.
///
/// Layout and Graphics use this to safely represent nodes for comparison purposes.
/// Because the script task's GC does not trace layout, node data cannot be safely stored in layout
/// data structures. Also, layout code tends to be faster when the DOM is not being accessed, for
/// locality reasons. Using `OpaqueNode` enforces this invariant.
#[derive(Clone, Copy, Debug, Eq, Hash, MallocSizeOf, PartialEq)]
#[cfg_attr(feature = "servo", derive(Deserialize, Serialize))]
pub struct OpaqueNode(pub usize);
impl OpaqueNode {
/// Returns the address of this node, for debugging purposes.
#[inline]
pub fn id(&self) -> usize {
self.0
}
}
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