Attachment 370020 Details for Bug 197939 – Patch

[patch] Patch

bug-197939-20190515192017.patch (text/plain), 3.69 KB, created by Simon Fraser (smfr) on 2019-05-15 19:20:18 PDT

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Creator: Simon Fraser (smfr)

Created: 2019-05-15 19:20:18 PDT

Size: 3.69 KB

patch

obsolete

>Subversion Revision: 245336
>diff --git a/Source/WebCore/ChangeLog b/Source/WebCore/ChangeLog
>index 9c8791c62d82b4fe72e2a1a141e5875309a0e8b7..ee2451f97ed0a51cc2678f8c8a3be73fe4a01092 100644
>--- a/Source/WebCore/ChangeLog
>+++ b/Source/WebCore/ChangeLog
>@@ -1,3 +1,20 @@
>+2019-05-15  Simon Fraser  <simon.fraser@apple.com>
>+
>+        Avoid a recursive descendants layer walk sometimes
>+        https://bugs.webkit.org/show_bug.cgi?id=197939
>+
>+        Reviewed by NOBODY (OOPS!).
>+
>+        If a layer got composited post-descendants because it needs to clip, for example, we'd do a recursive
>+        descendant tree walk to add layers to the overlap map. However, all the descendants would already
>+        have contributed to the overlap map if some non-root ancestor was already composited. So we can
>+        skip the addDescendantsToOverlapMapRecursive() if we know, before descendants, whether there's
>+        a non-root composited ancestor.
>+
>+        * rendering/RenderLayerCompositor.cpp:
>+        (WebCore::RenderLayerCompositor::CompositingState::hasNonRootCompositedAncestor const):
>+        (WebCore::RenderLayerCompositor::computeCompositingRequirements):
>+
> 2019-05-15  Simon Fraser  <simon.fraser@apple.com>
> 
>         Clean up code related to compositing overlap map maintenance
>diff --git a/Source/WebCore/rendering/RenderLayerCompositor.cpp b/Source/WebCore/rendering/RenderLayerCompositor.cpp
>index 166c4119ffeefd0dd2fa3cf3d57f48d3124f6492..81d3ef004a9168b08051e5758755aa656969e68f 100644
>--- a/Source/WebCore/rendering/RenderLayerCompositor.cpp
>+++ b/Source/WebCore/rendering/RenderLayerCompositor.cpp
>@@ -175,6 +175,11 @@ struct RenderLayerCompositor::CompositingState {
> #endif
>     }
> 
>+    bool hasNonRootCompositedAncestor() const
>+    {
>+        return compositingAncestor && !compositingAncestor->isRenderViewLayer();
>+    }
>+
>     RenderLayer* compositingAncestor;
>     RenderLayer* backingSharingAncestor { nullptr };
>     RenderLayer* stackingContextAncestor { nullptr };
>@@ -855,6 +860,7 @@ void RenderLayerCompositor::computeCompositingRequirements(RenderLayer* ancestor
>     RequiresCompositingData queryData;
>     bool willBeComposited = layer.isComposited();
>     bool becameCompositedAfterDescendantTraversal = false;
>+
>     if (layer.needsPostLayoutCompositingUpdate() || compositingState.fullPaintOrderTraversalRequired || compositingState.descendantsRequireCompositingUpdate) {
>         layer.setIndirectCompositingReason(RenderLayer::IndirectCompositingReason::None);
>         willBeComposited = needsToBeComposited(layer, queryData);
>@@ -951,6 +957,7 @@ void RenderLayerCompositor::computeCompositingRequirements(RenderLayer* ancestor
> #endif
> 
>     bool anyDescendantHas3DTransform = false;
>+    bool descendantsAddedToOverlap = currentState.hasNonRootCompositedAncestor();
> 
>     for (auto* childLayer : layer.negativeZOrderLayers()) {
>         computeCompositingRequirements(&layer, *childLayer, overlapMap, currentState, backingSharingState, anyDescendantHas3DTransform);
>@@ -1048,7 +1055,7 @@ void RenderLayerCompositor::computeCompositingRequirements(RenderLayer* ancestor
>     compositingState.updateWithDescendantStateAndLayer(currentState, layer, layerExtent);
> 
>     bool layerContributesToOverlap = currentState.compositingAncestor && !currentState.compositingAncestor->isRenderViewLayer();
>-    updateOverlapMap(overlapMap, layer, layerExtent, layerContributesToOverlap, becameCompositedAfterDescendantTraversal);
>+    updateOverlapMap(overlapMap, layer, layerExtent, layerContributesToOverlap, becameCompositedAfterDescendantTraversal && !descendantsAddedToOverlap);
> 
>     // Pop backing/overlap sharing state.
>     if ((willBeComposited && !layer.isRenderViewLayer()) || currentState.backingSharingAncestor == &layer) {

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