Use reference for FillLayer if possible

Source/core/rendering/RenderBox.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2005 Allan Sandfeld Jensen (kde@carewolf.com)
  *           (C) 2005, 2006 Samuel Weinig (sam.weinig@gmail.com)
  * Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2013 Adobe Systems Incorporated. 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
@@ skipping 1085 matching lines @@
         child->paint(childInfo, adjustedPaintOffset);
 }
 
 void RenderBox::paintRootBoxFillLayers(const PaintInfo& paintInfo)
 {
     if (paintInfo.skipRootBackground())
         return;
 
     RenderObject* rootBackgroundRenderer = rendererForRootBackground();
 
-    const FillLayer* bgLayer = rootBackgroundRenderer->style()->backgroundLayers();
+    const FillLayer& bgLayer = rootBackgroundRenderer->style()->backgroundLayers();
     Color bgColor = rootBackgroundRenderer->resolveColor(CSSPropertyBackgroundColor);
 
     paintFillLayers(paintInfo, bgColor, bgLayer, view()->backgroundRect(this), BackgroundBleedNone, CompositeSourceOver, rootBackgroundRenderer);
 }
 
 BackgroundBleedAvoidance RenderBox::determineBackgroundBleedAvoidance(GraphicsContext* context) const
 {
     if (context->paintingDisabled())
         return BackgroundBleedNone;
 
@@ skipping 92 matching lines @@
 {
     ASSERT(hasBackground());
     LayoutRect backgroundRect = pixelSnappedIntRect(borderBoxRect());
 
     Color backgroundColor = resolveColor(CSSPropertyBackgroundColor);
     if (backgroundColor.alpha()) {
         paintedExtent = backgroundRect;
         return true;
     }
 
-    if (!style()->backgroundLayers()->image() || style()->backgroundLayers()->next()) {
+    if (!style()->backgroundLayers().image() || style()->backgroundLayers().next()) {
         paintedExtent =  backgroundRect;
         return true;
     }
 
     BackgroundImageGeometry geometry;
     calculateBackgroundImageGeometry(0, style()->backgroundLayers(), backgroundRect, geometry);
     if (geometry.hasNonLocalGeometry())
         return false;
     paintedExtent = geometry.destRect();
     return true;
@@ skipping 13 matching lines @@
     // In this case it is safe to not assume opaqueness.
     // FIXME: May be ask theme if it paints opaque.
     if (style()->hasAppearance())
         return false;
     // FIXME: Check the opaqueness of background images.
 
     // FIXME: Use rounded rect if border radius is present.
     if (style()->hasBorderRadius())
         return false;
     // FIXME: The background color clip is defined by the last layer.
-    if (style()->backgroundLayers()->next())
+    if (style()->backgroundLayers().next())
         return false;
     LayoutRect backgroundRect;
     switch (style()->backgroundClip()) {
     case BorderFillBox:
         backgroundRect = borderBoxRect();
         break;
     case PaddingFillBox:
         backgroundRect = paddingBoxRect();
         break;
     case ContentFillBox:
@@ skipping 73 matching lines @@
     if (style()->boxShadow())
         return false;
     LayoutRect backgroundRect;
     if (!getBackgroundPaintedExtent(backgroundRect))
         return false;
     return foregroundIsKnownToBeOpaqueInRect(backgroundRect, backgroundObscurationTestMaxDepth);
 }
 
 bool RenderBox::backgroundHasOpaqueTopLayer() const
 {
-    const FillLayer* fillLayer = style()->backgroundLayers();
-    if (!fillLayer || fillLayer->clip() != BorderFillBox)
+    const FillLayer& fillLayer = style()->backgroundLayers();
+    if (fillLayer.clip() != BorderFillBox)
         return false;
 
     // Clipped with local scrolling
-    if (hasOverflowClip() && fillLayer->attachment() == LocalBackgroundAttachment)
+    if (hasOverflowClip() && fillLayer.attachment() == LocalBackgroundAttachment)
         return false;
 
-    if (fillLayer->hasOpaqueImage(this) && fillLayer->hasRepeatXY() && fillLayer->image()->canRender(*this, style()->effectiveZoom()))
+    if (fillLayer.hasOpaqueImage(this) && fillLayer.hasRepeatXY() && fillLayer.image()->canRender(*this, style()->effectiveZoom()))
         return true;
 
     // If there is only one layer and no image, check whether the background color is opaque
-    if (!fillLayer->next() && !fillLayer->hasImage()) {
+    if (!fillLayer.next() && !fillLayer.hasImage()) {
         Color bgColor = resolveColor(CSSPropertyBackgroundColor);
         if (bgColor.alpha() == 255)
             return true;
     }
 
     return false;
 }
 
 void RenderBox::paintMask(PaintInfo& paintInfo, const LayoutPoint& paintOffset)
 {
@@ skipping 26 matching lines @@
     bool pushTransparencyLayer = false;
     bool compositedMask = hasLayer() && layer()->hasCompositedMask();
     bool flattenCompositingLayers = view()->frameView() && view()->frameView()->paintBehavior() & PaintBehaviorFlattenCompositingLayers;
     CompositeOperator compositeOp = CompositeSourceOver;
 
     bool allMaskImagesLoaded = true;
 
     if (!compositedMask || flattenCompositingLayers) {
         pushTransparencyLayer = true;
         StyleImage* maskBoxImage = style()->maskBoxImage().image();
-        const FillLayer* maskLayers = style()->maskLayers();
+        const FillLayer& maskLayers = style()->maskLayers();
 
         // Don't render a masked element until all the mask images have loaded, to prevent a flash of unmasked content.
         if (maskBoxImage)
             allMaskImagesLoaded &= maskBoxImage->isLoaded();
 
-        if (maskLayers)
-            allMaskImagesLoaded &= maskLayers->imagesAreLoaded();
+        allMaskImagesLoaded &= maskLayers.imagesAreLoaded();
 
         paintInfo.context->setCompositeOperation(CompositeDestinationIn);
         paintInfo.context->beginTransparencyLayer(1);
         compositeOp = CompositeSourceOver;
     }
 
     if (allMaskImagesLoaded) {
         paintFillLayers(paintInfo, Color::transparent, style()->maskLayers(), paintRect, BackgroundBleedNone, compositeOp);
         paintNinePieceImage(paintInfo.context, paintRect, style(), style()->maskBoxImage(), compositeOp);
     }
 
     if (pushTransparencyLayer)
         paintInfo.context->endLayer();
 }
 
-void RenderBox::paintFillLayers(const PaintInfo& paintInfo, const Color& c, const FillLayer* fillLayer, const LayoutRect& rect,
+void RenderBox::paintFillLayers(const PaintInfo& paintInfo, const Color& c, const FillLayer& fillLayer, const LayoutRect& rect,
     BackgroundBleedAvoidance bleedAvoidance, CompositeOperator op, RenderObject* backgroundObject)
 {
     Vector<const FillLayer*, 8> layers;
-    const FillLayer* curLayer = fillLayer;
+    const FillLayer* curLayer = &fillLayer;
     bool shouldDrawBackgroundInSeparateBuffer = false;
     while (curLayer) {
         layers.append(curLayer);
         // Stop traversal when an opaque layer is encountered.
         // FIXME : It would be possible for the following occlusion culling test to be more aggressive
         // on layers with no repeat by testing whether the image covers the layout rect.
         // Testing that here would imply duplicating a lot of calculations that are currently done in
         // RenderBoxModelObject::paintFillLayerExtended. A more efficient solution might be to move
         // the layer recursion into paintFillLayerExtended, or to compute the layer geometry here
         // and pass it down.
 
         if (!shouldDrawBackgroundInSeparateBuffer && curLayer->blendMode() != blink::WebBlendModeNormal)
             shouldDrawBackgroundInSeparateBuffer = true;
 
         // The clipOccludesNextLayers condition must be evaluated first to avoid short-circuiting.
-        if (curLayer->clipOccludesNextLayers(curLayer == fillLayer) && curLayer->hasOpaqueImage(this) && curLayer->image()->canRender(*this, style()->effectiveZoom()) && curLayer->hasRepeatXY() && curLayer->blendMode() == blink::WebBlendModeNormal && !boxShadowShouldBeAppliedToBackground(bleedAvoidance))
+        if (curLayer->clipOccludesNextLayers(curLayer == &fillLayer) && curLayer->hasOpaqueImage(this) && curLayer->image()->canRender(*this, style()->effectiveZoom()) && curLayer->hasRepeatXY() && curLayer->blendMode() == blink::WebBlendModeNormal && !boxShadowShouldBeAppliedToBackground(bleedAvoidance))
             break;
         curLayer = curLayer->next();
     }
 
     GraphicsContext* context = paintInfo.context;
     if (!context)
         shouldDrawBackgroundInSeparateBuffer = false;
     if (shouldDrawBackgroundInSeparateBuffer)
         context->beginTransparencyLayer(1);
 
     Vector<const FillLayer*>::const_reverse_iterator topLayer = layers.rend();
     for (Vector<const FillLayer*>::const_reverse_iterator it = layers.rbegin(); it != topLayer; ++it)
-        paintFillLayer(paintInfo, c, *it, rect, bleedAvoidance, op, backgroundObject);
+        paintFillLayer(paintInfo, c, **it, rect, bleedAvoidance, op, backgroundObject);
 
     if (shouldDrawBackgroundInSeparateBuffer)
         context->endLayer();
 }
 
-void RenderBox::paintFillLayer(const PaintInfo& paintInfo, const Color& c, const FillLayer* fillLayer, const LayoutRect& rect,
+void RenderBox::paintFillLayer(const PaintInfo& paintInfo, const Color& c, const FillLayer& fillLayer, const LayoutRect& rect,
     BackgroundBleedAvoidance bleedAvoidance, CompositeOperator op, RenderObject* backgroundObject)
 {
     paintFillLayerExtended(paintInfo, c, fillLayer, rect, bleedAvoidance, 0, LayoutSize(), op, backgroundObject);
 }
 
 void RenderBox::imageChanged(WrappedImagePtr image, const IntRect*)
 {
     if (!parent())
         return;
 
     AllowPaintInvalidationScope scoper(frameView());
 
     if ((style()->borderImage().image() && style()->borderImage().image()->data() == image) ||
         (style()->maskBoxImage().image() && style()->maskBoxImage().image()->data() == image)) {
         paintInvalidationForWholeRenderer();
         return;
     }
 
     ShapeValue* shapeOutsideValue = style()->shapeOutside();
     if (!frameView()->isInPerformLayout() && isFloating() && shapeOutsideValue && shapeOutsideValue->image() && shapeOutsideValue->image()->data() == image) {
         ShapeOutsideInfo::ensureInfo(*this).markShapeAsDirty();
         markShapeOutsideDependentsForLayout();
     }
 
     bool didFullRepaint = repaintLayerRectsForImage(image, style()->backgroundLayers(), true);
     if (!didFullRepaint)
         repaintLayerRectsForImage(image, style()->maskLayers(), false);
 }
 
-bool RenderBox::repaintLayerRectsForImage(WrappedImagePtr image, const FillLayer* layers, bool drawingBackground)
+bool RenderBox::repaintLayerRectsForImage(WrappedImagePtr image, const FillLayer& layers, bool drawingBackground)
 {
     LayoutRect rendererRect;
     RenderBox* layerRenderer = 0;
 
-    for (const FillLayer* curLayer = layers; curLayer; curLayer = curLayer->next()) {
+    for (const FillLayer* curLayer = &layers; curLayer; curLayer = curLayer->next()) {
         if (curLayer->image() && image == curLayer->image()->data() && curLayer->image()->canRender(*this, style()->effectiveZoom())) {
             // Now that we know this image is being used, compute the renderer and the rect if we haven't already.
             if (!layerRenderer) {
                 bool drawingRootBackground = drawingBackground && (isDocumentElement() || (isBody() && !document().documentElement()->renderer()->hasBackground()));
                 if (drawingRootBackground) {
                     layerRenderer = view();
 
                     LayoutUnit rw;
                     LayoutUnit rh;
 
                     if (FrameView* frameView = toRenderView(layerRenderer)->frameView()) {
                         rw = frameView->contentsWidth();
                         rh = frameView->contentsHeight();
                     } else {
                         rw = layerRenderer->width();
                         rh = layerRenderer->height();
                     }
                     rendererRect = LayoutRect(-layerRenderer->marginLeft(),
                         -layerRenderer->marginTop(),
                         std::max(layerRenderer->width() + layerRenderer->marginWidth() + layerRenderer->borderLeft() + layerRenderer->borderRight(), rw),
                         std::max(layerRenderer->height() + layerRenderer->marginHeight() + layerRenderer->borderTop() + layerRenderer->borderBottom(), rh));
                 } else {
                     layerRenderer = this;
                     rendererRect = borderBoxRect();
                 }
             }
 
             BackgroundImageGeometry geometry;
-            layerRenderer->calculateBackgroundImageGeometry(0, curLayer, rendererRect, geometry);
+            layerRenderer->calculateBackgroundImageGeometry(0, *curLayer, rendererRect, geometry);
             if (geometry.hasNonLocalGeometry()) {
                 // Rather than incur the costs of computing the paintContainer for renderers with fixed backgrounds
                 // in order to get the right destRect, just repaint the entire renderer.
                 layerRenderer->paintInvalidationForWholeRenderer();
                 return true;
             }
 
             layerRenderer->invalidatePaintRectangle(geometry.destRect());
             if (geometry.destRect() == rendererRect)
                 return true;
@@ skipping 3104 matching lines @@
         return 0;
 
     if (!layoutState && !flowThreadContainingBlock())
         return 0;
 
     RenderBlock* containerBlock = containingBlock();
     return containerBlock->offsetFromLogicalTopOfFirstPage() + logicalTop();
 }
 
 } // namespace WebCore