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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.
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Source-Repo: https://github.com/servo/servo
Source-Revision: bb54f0a429de0e8b8861f8071b6cf82f73622664
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This is preliminar work for the style attribute restyle hint.
Source-Repo: https://github.com/servo/servo
Source-Revision: 7a40f472337f0a9a44e2146f4005ec99da38f96b
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Source-Repo: https://github.com/servo/servo
Source-Revision: 40917e7991ddd0f1fdcf83f0bf637a721f37256a
CSSOM is now starting to be useful!
Based on #14190. Only the <s>last commit</s> last two commits need review.
cc @xidorn . This doesn't change the style API, but adds useful methods.
part of #11420
This adds:
- `insertRule()` and `deleteRule()` on `CSSStyleSheet`, `CSSGroupingRule`
- `.style` getters on link and style elements
- Keyframes-backed `CSSRules` and `CSSKeyframesRule.cssRules`
- `CSSGroupingRule.cssRules`
- `prefix` and `namespaceURI` attributes of `CSSNamespaceRule`
- Fixups regarding parent stylesheets
r? @SimonSapin
Source-Repo: https://github.com/servo/servo
Source-Revision: 996756687cd741ad0d30029022638bdcceecb563
