зеркало из https://github.com/mozilla/gecko-dev.git
82 строки
2.7 KiB
Rust
82 строки
2.7 KiB
Rust
/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at https://mozilla.org/MPL/2.0/. */
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use fxhash::FxHashMap;
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/// Relative selector cache. This is useful for following cases.
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/// First case is non-subject relative selector: Imagine `.anchor:has(<..>) ~ .foo`, with DOM
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/// `.anchor + .foo + .. + .foo`. Each match on `.foo` triggers `:has()` traversal that
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/// yields the same result. This is simple enough, since we just need to store
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/// the exact match on that anchor pass/fail.
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/// Second case is `querySelectorAll`: Imagine `querySelectorAll(':has(.a)')`, with DOM
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/// `div > .. > div > .a`. When the we perform the traversal at the top div,
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/// we basically end up evaluating `:has(.a)` for all anchors, which could be reused.
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/// Also consider the sibling version: `querySelectorAll(':has(~ .a)')` with DOM
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/// `div + .. + div + .a`.
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/// TODO(dshin): Second case is not yet handled. That is tracked in Bug 1845291.
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use std::hash::Hash;
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use crate::parser::{RelativeSelector, SelectorKey};
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use crate::{tree::OpaqueElement, SelectorImpl};
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/// Match data for a given element and a selector.
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#[derive(Clone, Copy)]
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pub enum RelativeSelectorCachedMatch {
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/// This selector matches this element.
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Matched,
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/// This selector does not match this element.
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NotMatched,
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}
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impl RelativeSelectorCachedMatch {
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/// Is the cached result a match?
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pub fn matched(&self) -> bool {
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matches!(*self, Self::Matched)
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}
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}
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#[derive(Clone, Copy, Hash, Eq, PartialEq)]
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struct Key {
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element: OpaqueElement,
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selector: SelectorKey,
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}
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impl Key {
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pub fn new<Impl: SelectorImpl>(
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element: OpaqueElement,
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selector: &RelativeSelector<Impl>,
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) -> Self {
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Key {
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element,
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selector: SelectorKey::new(&selector.selector),
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}
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}
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}
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/// Cache to speed up matching of relative selectors.
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#[derive(Default)]
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pub struct RelativeSelectorCache {
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cache: FxHashMap<Key, RelativeSelectorCachedMatch>,
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}
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impl RelativeSelectorCache {
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/// Add a relative selector match into the cache.
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pub fn add<Impl: SelectorImpl>(
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&mut self,
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anchor: OpaqueElement,
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selector: &RelativeSelector<Impl>,
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matched: RelativeSelectorCachedMatch,
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) {
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self.cache.insert(Key::new(anchor, selector), matched);
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}
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/// Check if we have a cache entry for the element.
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pub fn lookup<Impl: SelectorImpl>(
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&mut self,
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element: OpaqueElement,
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selector: &RelativeSelector<Impl>,
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) -> Option<RelativeSelectorCachedMatch> {
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self.cache.get(&Key::new(element, selector)).copied()
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}
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}
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