Prevent reading stale/invalid data when applying a <pattern>

Source/core/rendering/svg/RenderSVGResourcePattern.cpp

 /*
  * Copyright (C) 2006 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) Research In Motion Limited 2010. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 34 matching lines @@
     markAllClientsForInvalidation(markForInvalidation ? PaintInvalidation : ParentOnlyInvalidation);
 }
 
 void RenderSVGResourcePattern::removeClientFromCache(RenderObject* client, bool markForInvalidation)
 {
     ASSERT(client);
     m_patternMap.remove(client);
     markClientForInvalidation(client, markForInvalidation ? PaintInvalidation : ParentOnlyInvalidation);
 }
 
-PatternData* RenderSVGResourcePattern::buildPattern(RenderObject* object, unsigned short resourceMode)
+PatternData* RenderSVGResourcePattern::buildPattern(RenderObject* object, const SVGPatternElement* patternElement)
 {
     ASSERT(object);
     PatternData* currentData = m_patternMap.get(object);
     if (currentData && currentData->pattern)
         return currentData;
 
-    SVGPatternElement* patternElement = toSVGPatternElement(element());
-    if (!patternElement)
-        return 0;
-
-    if (m_shouldCollectPatternAttributes) {
-        patternElement->synchronizeAnimatedSVGAttribute(anyQName());
-
-        m_attributes = PatternAttributes();
-        patternElement->collectPatternAttributes(m_attributes);
-        m_shouldCollectPatternAttributes = false;
-    }
-
     // If we couldn't determine the pattern content element root, stop here.
     if (!m_attributes.patternContentElement())
         return 0;
 
     // An empty viewBox disables rendering.
     if (m_attributes.hasViewBox() && m_attributes.viewBox().isEmpty())
         return 0;
 
     // Compute all necessary transformations to build the tile image & the pattern.
     FloatRect tileBoundaries;
@@ skipping 42 matching lines @@
 
 bool RenderSVGResourcePattern::applyResource(RenderObject* object, RenderStyle* style, GraphicsContext*& context, unsigned short resourceMode)
 {
     ASSERT(object);
     ASSERT(style);
     ASSERT(context);
     ASSERT(resourceMode != ApplyToDefaultMode);
 
     clearInvalidationMask();
 
+    SVGPatternElement* patternElement = toSVGPatternElement(element());
+    if (!patternElement)
+        return false;
+
+    if (m_shouldCollectPatternAttributes) {
+        patternElement->synchronizeAnimatedSVGAttribute(anyQName());
+
+        m_attributes = PatternAttributes();
+        patternElement->collectPatternAttributes(m_attributes);
+        m_shouldCollectPatternAttributes = false;
+    }
+
     // Spec: When the geometry of the applicable element has no width or height and objectBoundingBox is specified,
     // then the given effect (e.g. a gradient or a filter) will be ignored.
     FloatRect objectBoundingBox = object->objectBoundingBox();
     if (m_attributes.patternUnits() == SVGUnitTypes::SVG_UNIT_TYPE_OBJECTBOUNDINGBOX && objectBoundingBox.isEmpty())
         return false;
 
-    PatternData* patternData = buildPattern(object, resourceMode);
+    PatternData* patternData = buildPattern(object, patternElement);
     if (!patternData)
         return false;
 
     const SVGRenderStyle& svgStyle = style->svgStyle();
 
     AffineTransform computedPatternSpaceTransform = computeResourceSpaceTransform(object, patternData->transform, svgStyle, resourceMode);
     patternData->pattern->setPatternSpaceTransform(computedPatternSpaceTransform);
 
     // Draw pattern
     context->save();
@@ skipping 95 matching lines @@
             continue;
         if (element->renderer()->needsLayout())
             return nullptr;
         SVGRenderingContext::renderSubtree(tileImage->context(), element->renderer(), contentTransformation);
     }
 
     return tileImage.release();
 }
 
 }