From 43a97878ce14b72f0981164f87f2e35e14151312 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 11:22:09 +0200 Subject: Adding upstream version 110.0.1. Signed-off-by: Daniel Baumann --- servo/components/selectors/nth_index_cache.rs | 52 +++++++++++++++++++++++++++ 1 file changed, 52 insertions(+) create mode 100644 servo/components/selectors/nth_index_cache.rs (limited to 'servo/components/selectors/nth_index_cache.rs') diff --git a/servo/components/selectors/nth_index_cache.rs b/servo/components/selectors/nth_index_cache.rs new file mode 100644 index 0000000000..979c310017 --- /dev/null +++ b/servo/components/selectors/nth_index_cache.rs @@ -0,0 +1,52 @@ +/* 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/. */ + +use crate::tree::OpaqueElement; +use fxhash::FxHashMap; + +/// A cache to speed up matching of nth-index-like selectors. +/// +/// See [1] for some discussion around the design tradeoffs. +/// +/// [1] https://bugzilla.mozilla.org/show_bug.cgi?id=1401855#c3 +#[derive(Default)] +pub struct NthIndexCache { + nth: NthIndexCacheInner, + nth_last: NthIndexCacheInner, + nth_of_type: NthIndexCacheInner, + nth_last_of_type: NthIndexCacheInner, +} + +impl NthIndexCache { + /// Gets the appropriate cache for the given parameters. + pub fn get(&mut self, is_of_type: bool, is_from_end: bool) -> &mut NthIndexCacheInner { + match (is_of_type, is_from_end) { + (false, false) => &mut self.nth, + (false, true) => &mut self.nth_last, + (true, false) => &mut self.nth_of_type, + (true, true) => &mut self.nth_last_of_type, + } + } +} + +/// The concrete per-pseudo-class cache. +#[derive(Default)] +pub struct NthIndexCacheInner(FxHashMap); + +impl NthIndexCacheInner { + /// Does a lookup for a given element in the cache. + pub fn lookup(&mut self, el: OpaqueElement) -> Option { + self.0.get(&el).copied() + } + + /// Inserts an entry into the cache. + pub fn insert(&mut self, element: OpaqueElement, index: i32) { + self.0.insert(element, index); + } + + /// Returns whether the cache is empty. + pub fn is_empty(&self) -> bool { + self.0.is_empty() + } +} -- cgit v1.2.3