forked from mirrors/gecko-dev
		
	 33a9e6d050
			
		
	
	
		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
		
			
				
	
	
		
			114 lines
		
	
	
	
		
			3.9 KiB
		
	
	
	
		
			Rust
		
	
	
	
	
	
			
		
		
	
	
			114 lines
		
	
	
	
		
			3.9 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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| 
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| use dom::bindings::codegen::Bindings::CSSStyleSheetBinding;
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| use dom::bindings::codegen::Bindings::CSSStyleSheetBinding::CSSStyleSheetMethods;
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| use dom::bindings::codegen::Bindings::WindowBinding::WindowBinding::WindowMethods;
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| use dom::bindings::error::{Error, ErrorResult, Fallible};
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| use dom::bindings::js::{JS, MutNullableJS, Root};
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| use dom::bindings::reflector::{reflect_dom_object, DomObject};
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| use dom::bindings::str::DOMString;
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| use dom::cssrulelist::{CSSRuleList, RulesSource};
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| use dom::element::Element;
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| use dom::stylesheet::StyleSheet;
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| use dom::window::Window;
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| use dom_struct::dom_struct;
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| use std::cell::Cell;
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| use std::sync::Arc;
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| use style::shared_lock::SharedRwLock;
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| use style::stylesheets::Stylesheet as StyleStyleSheet;
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| 
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| #[dom_struct]
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| pub struct CSSStyleSheet {
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|     stylesheet: StyleSheet,
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|     owner: JS<Element>,
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|     rulelist: MutNullableJS<CSSRuleList>,
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|     #[ignore_heap_size_of = "Arc"]
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|     style_stylesheet: Arc<StyleStyleSheet>,
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|     origin_clean: Cell<bool>,
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| }
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| 
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| impl CSSStyleSheet {
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|     fn new_inherited(owner: &Element,
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|                      type_: DOMString,
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|                      href: Option<DOMString>,
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|                      title: Option<DOMString>,
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|                      stylesheet: Arc<StyleStyleSheet>) -> CSSStyleSheet {
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|         CSSStyleSheet {
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|             stylesheet: StyleSheet::new_inherited(type_, href, title),
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|             owner: JS::from_ref(owner),
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|             rulelist: MutNullableJS::new(None),
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|             style_stylesheet: stylesheet,
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|             origin_clean: Cell::new(true),
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|         }
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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,
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|                owner: &Element,
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|                type_: DOMString,
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|                href: Option<DOMString>,
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|                title: Option<DOMString>,
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|                stylesheet: Arc<StyleStyleSheet>) -> Root<CSSStyleSheet> {
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|         reflect_dom_object(box CSSStyleSheet::new_inherited(owner, type_, href, title, stylesheet),
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|                            window,
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|                            CSSStyleSheetBinding::Wrap)
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|     }
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| 
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|     fn rulelist(&self) -> Root<CSSRuleList> {
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|         self.rulelist.or_init(|| CSSRuleList::new(self.global().as_window(),
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|                                                   self,
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|                                                   RulesSource::Rules(self.style_stylesheet
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|                                                                          .rules.clone())))
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|     }
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| 
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|     pub fn disabled(&self) -> bool {
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|         self.style_stylesheet.disabled()
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|     }
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| 
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|     pub fn set_disabled(&self, disabled: bool) {
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|         if self.style_stylesheet.set_disabled(disabled) {
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|             self.global().as_window().Document().invalidate_stylesheets();
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|         }
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|     }
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| 
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|     pub fn shared_lock(&self) -> &SharedRwLock {
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|         &self.style_stylesheet.shared_lock
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|     }
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| 
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|     pub fn style_stylesheet(&self) -> &StyleStyleSheet {
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|         &self.style_stylesheet
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|     }
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| 
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|     pub fn set_origin_clean(&self, origin_clean: bool) {
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|         self.origin_clean.set(origin_clean);
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|     }
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| }
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| 
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| impl CSSStyleSheetMethods for CSSStyleSheet {
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|     // https://drafts.csswg.org/cssom/#dom-cssstylesheet-cssrules
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|     fn GetCssRules(&self) -> Fallible<Root<CSSRuleList>> {
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|         if !self.origin_clean.get() {
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|             return Err(Error::Security);
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|         }
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|         Ok(self.rulelist())
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|     }
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| 
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|     // https://drafts.csswg.org/cssom/#dom-cssstylesheet-insertrule
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|     fn InsertRule(&self, rule: DOMString, index: u32) -> Fallible<u32> {
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|         if !self.origin_clean.get() {
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|             return Err(Error::Security);
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|         }
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|         self.rulelist().insert_rule(&rule, index, /* nested */ false)
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|     }
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| 
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|     // https://drafts.csswg.org/cssom/#dom-cssstylesheet-deleterule
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|     fn DeleteRule(&self, index: u32) -> ErrorResult {
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|         if !self.origin_clean.get() {
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|             return Err(Error::Security);
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|         }
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|         self.rulelist().remove_rule(index)
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|     }
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| }
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| 
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