mirror of
https://github.com/LadybirdBrowser/ladybird
synced 2026-04-26 09:45:06 +02:00
b6559d3846
Avoid forcing a full style update when a connected inline <style> sheet inserts an ordinary style rule. Build a targeted invalidation set from the inserted rule and walk only the affected roots instead. Introduce the shared StyleSheetInvalidation helper so later stylesheet mutation paths can reuse the same selector analysis and root application logic. It handles trailing-universal selectors, pseudo-element-only rightmost compounds, and shadow-host escapes through ::slotted(...) and :host combinators. Keep the broad invalidate_owners() path for constructed stylesheets and other sheet kinds whose TreeScope interactions still require it.
62 lines
2.8 KiB
HTML
62 lines
2.8 KiB
HTML
<!DOCTYPE html>
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<script src="../include.js"></script>
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<style id="document-style"></style>
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<div id="document-target" class="foo">document target</div>
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<div>document bystander 1</div>
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<div>document bystander 2</div>
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<div>document bystander 3</div>
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<div id="shadow-host"></div>
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<script>
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function settleAndReset(triggerElement) {
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// Force style resolution before we observe counters so the subsequent
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// mutation is measured in isolation.
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getComputedStyle(triggerElement).color;
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getComputedStyle(triggerElement).color;
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internals.resetStyleInvalidationCounters();
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}
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function addBystanders(parent, prefix, count) {
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for (let i = 0; i < count; ++i) {
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const bystander = document.createElement("div");
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bystander.textContent = `${prefix} bystander ${i}`;
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parent.appendChild(bystander);
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}
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}
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function verifyInvalidationsStayNarrow(label, maxInvalidations) {
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const invalidations = internals.getStyleInvalidationCounters().styleInvalidations;
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if (invalidations <= maxInvalidations)
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println(`PASS: ${label} (${invalidations} invalidations)`);
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else
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println(`FAIL: ${label} (${invalidations} invalidations)`);
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}
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test(() => {
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const documentTarget = document.getElementById("document-target");
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// A large set of unrelated bystanders makes it obvious whether the
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// invalidation cost scales with the whole subtree or just the match.
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addBystanders(document.body, "document", 25);
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const documentStyleSheet = document.getElementById("document-style").sheet;
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settleAndReset(documentTarget);
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documentStyleSheet.insertRule(".foo { color: rgb(255, 0, 0); }", documentStyleSheet.cssRules.length);
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getComputedStyle(documentTarget).color;
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verifyInvalidationsStayNarrow("document insertRule stays targeted across many bystanders", 1);
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const shadowRoot = document.getElementById("shadow-host").attachShadow({ mode: "open" });
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shadowRoot.innerHTML = `
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<style id="shadow-style"></style>
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<div id="shadow-target" class="foo">shadow target</div>
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`;
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addBystanders(shadowRoot, "shadow", 25);
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const shadowTarget = shadowRoot.getElementById("shadow-target");
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const shadowStyleSheet = shadowRoot.getElementById("shadow-style").sheet;
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settleAndReset(shadowTarget);
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shadowStyleSheet.insertRule(".foo { color: rgb(0, 128, 0); }", shadowStyleSheet.cssRules.length);
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getComputedStyle(shadowTarget).color;
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// Shadow-root sheets can legitimately dirty both the matching shadow
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// descendant and the host when the sheet gains selectors such as :host.
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verifyInvalidationsStayNarrow("shadow insertRule stays targeted across many bystanders", 2);
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});
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</script>
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