Changeset 224269 in webkit

Timestamp:

Oct 31, 2017 6:39:09 PM (6 years ago)

Author:

commit-queue@webkit.org

Message:

updateMaskedAncestorShouldIsolateBlending() should check the Nullability of the computedStyle() of the element's ancestors
​https://bugs.webkit.org/show_bug.cgi?id=179085
<rdar://problem/30888101>

Patch by Said Abou-Hallawa <​sabouhallawa@apple.com> on 2017-10-31
Reviewed by Ryosuke Niwa.

This is a defensive change. The Element::computedStyle() can be null only
if the element is not a connected to the DOM tree. This may happen if
while the DOM tree is being changed, a different event is handled such
that it requires styleReclac()/layout() to happen. In this case, the render
tree will be in an incorrect state.

• rendering/svg/SVGRenderSupport.cpp:

(WebCore::SVGRenderSupport::updateMaskedAncestorShouldIsolateBlending):

Location:

trunk/Source/WebCore

Files:

• ChangeLog (modified) (1 diff)
• rendering/svg/SVGRenderSupport.cpp (modified) (1 diff)

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2017-10-31  Said Abou-Hallawa  <sabouhallawa@apple.com>
+
+        updateMaskedAncestorShouldIsolateBlending() should check the Nullability of the computedStyle() of the element's ancestors
+        https://bugs.webkit.org/show_bug.cgi?id=179085
+        <rdar://problem/30888101>
+
+        Reviewed by Ryosuke Niwa.
+
+        This is a defensive change. The Element::computedStyle() can be null only
+        if the element is not a connected to the DOM tree. This may happen if
+        while the DOM tree is being changed, a different event is handled such
+        that it requires styleReclac()/layout() to happen. In this case, the render
+        tree will be in an incorrect state.
+
+        * rendering/svg/SVGRenderSupport.cpp:
+        (WebCore::SVGRenderSupport::updateMaskedAncestorShouldIsolateBlending):
+
 2017-10-31  Alex Christensen  <achristensen@webkit.org>
 

trunk/Source/WebCore/rendering/svg/SVGRenderSupport.cpp

@@ -486 +486 @@
     bool maskedAncestorShouldIsolateBlending = renderer.style().hasBlendMode();
     for (auto* ancestor = renderer.element()->parentElement(); ancestor && ancestor->isSVGElement(); ancestor = ancestor->parentElement()) {
-        if (!downcast<SVGElement>(*ancestor).isSVGGraphicsElement() || !isolatesBlending(*ancestor->computedStyle()))
+        if (!downcast<SVGElement>(*ancestor).isSVGGraphicsElement())
+            continue;
+
+        const auto* style = ancestor->computedStyle();
+        if (!style || !isolatesBlending(*style))
             continue;