forked from mirrors/gecko-dev
33a9e6d050
<!-- Please describe your changes on the following line: --> Before this PR, every object reflected in CSSOM is in `Arc<RwLock<_>>` to enable safe (synchronized) mutable aliasing. Acquiring all these locks has significant cost during selector matching: * https://bugzilla.mozilla.org/show_bug.cgi?id=1311469 * https://bugzilla.mozilla.org/show_bug.cgi?id=1335941 * https://bugzilla.mozilla.org/show_bug.cgi?id=1339703 This PR introduce a mechanism to protect many objects with the same `RwLock` that only needs to be acquired once. In Stylo, there is one such lock per process (in a `lazy_static`), used for everything. I non-Stylo Servo, I originally intended to have one such lock per document (for author-origin stylesheets, and one per process for user-agent and user sytlesheets since they’re shared across documents, and never mutated anyway). However I failed to have the same document-specific (or pipeline-specific) `Arc` reachable from both `Document` nodes and `LayoutThread`. Recursively following callers lead me to include this `Arc` in `UnprivilegedPipelineContent`, but that needs to be serializable. So there is a second process-wide lock. This was previously #15998, closed accidentally. --- <!-- Thank you for contributing to Servo! Please replace each `[ ]` by `[X]` when the step is complete, and replace `__` with appropriate data: --> - [x] `./mach build -d` does not report any errors - [x] `./mach test-tidy` does not report any errors - [ ] These changes fix #__ (github issue number if applicable). <!-- Either: --> - [ ] There are tests for these changes OR - [ ] These changes do not require tests because _____ <!-- Pull requests that do not address these steps are welcome, but they will require additional verification as part of the review process. --> Source-Repo: https://github.com/servo/servo Source-Revision: bb54f0a429de0e8b8861f8071b6cf82f73622664 --HG-- extra : subtree_source : https%3A//hg.mozilla.org/projects/converted-servo-linear extra : subtree_revision : 851230e57ac8775707df5f0f103be5feac81fc41
51 lines
1.8 KiB
Rust
51 lines
1.8 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 http://mozilla.org/MPL/2.0/. */
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use dom::bindings::codegen::Bindings::CSSViewportRuleBinding;
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use dom::bindings::js::Root;
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use dom::bindings::reflector::reflect_dom_object;
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use dom::bindings::str::DOMString;
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use dom::cssrule::{CSSRule, SpecificCSSRule};
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use dom::cssstylesheet::CSSStyleSheet;
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use dom::window::Window;
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use dom_struct::dom_struct;
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use std::sync::Arc;
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use style::shared_lock::{Locked, ToCssWithGuard};
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use style::viewport::ViewportRule;
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#[dom_struct]
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pub struct CSSViewportRule {
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cssrule: CSSRule,
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#[ignore_heap_size_of = "Arc"]
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viewportrule: Arc<Locked<ViewportRule>>,
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}
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impl CSSViewportRule {
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fn new_inherited(parent_stylesheet: &CSSStyleSheet, viewportrule: Arc<Locked<ViewportRule>>) -> CSSViewportRule {
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CSSViewportRule {
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cssrule: CSSRule::new_inherited(parent_stylesheet),
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viewportrule: viewportrule,
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}
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}
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#[allow(unrooted_must_root)]
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pub fn new(window: &Window, parent_stylesheet: &CSSStyleSheet,
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viewportrule: Arc<Locked<ViewportRule>>) -> Root<CSSViewportRule> {
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reflect_dom_object(box CSSViewportRule::new_inherited(parent_stylesheet, viewportrule),
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window,
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CSSViewportRuleBinding::Wrap)
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}
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}
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impl SpecificCSSRule for CSSViewportRule {
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fn ty(&self) -> u16 {
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use dom::bindings::codegen::Bindings::CSSRuleBinding::CSSRuleConstants;
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CSSRuleConstants::VIEWPORT_RULE
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}
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fn get_css(&self) -> DOMString {
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let guard = self.cssrule.shared_lock().read();
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self.viewportrule.read_with(&guard).to_css_string(&guard).into()
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}
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}
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