Improve positioned/percentHeight descendant/container tracking

third_party/WebKit/Source/core/layout/LayoutBox.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2003, 2006, 2007 Apple Inc. 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.
  *
@@ skipping 40 matching lines @@
 
 struct LayoutBoxRareData {
     WTF_MAKE_NONCOPYABLE(LayoutBoxRareData); USING_FAST_MALLOC(LayoutBoxRareData);
 public:
     LayoutBoxRareData()
         : m_inlineBoxWrapper(nullptr)
         , m_spannerPlaceholder(nullptr)
         , m_overrideLogicalContentHeight(-1)
         , m_overrideLogicalContentWidth(-1)
         , m_previousBorderBoxSize(-1, -1)
+        , m_positionedContainer(nullptr)
+        , m_percentHeightContainer(nullptr)
     {
     }
+    virtual ~LayoutBoxRareData() { }

[esprehn, 2016/01/06 19:37:25]

we make this non-virtual in ElementRareData/NodeRareData and make it the
responsibility of the owner to destroy it at the correct type which saves 1 ptr
(the vtable) for every rare data.

[Xianzhu, 2016/01/06 20:49:07]

Done.

 
     // For inline replaced elements, the inline box that owns us.
     InlineBox* m_inlineBoxWrapper;
 
     // For spanners, the spanner placeholder that lays us out within the multicol container.
     LayoutMultiColumnSpannerPlaceholder* m_spannerPlaceholder;
 
     LayoutUnit m_overrideLogicalContentHeight;
     LayoutUnit m_overrideLogicalContentWidth;
 
     // Set by LayoutBox::savePreviousBoxSizesIfNeeded().
     LayoutSize m_previousBorderBoxSize;
     LayoutRect m_previousContentBoxRect;
     LayoutRect m_previousLayoutOverflowRect;
 
     LayoutUnit m_pageLogicalOffset;
 
     LayoutUnit m_paginationStrut;
+
+    // Points to the LayoutBlock whose LayoutBlockRareData::m_positionedDescendants contains this LayoutBox.
+    LayoutBlock* m_positionedContainer;
+    // Points to the LayoutBlock whose LayoutBlockRareData::m_percentHeightDescendants contains this LayoutBox.
+    LayoutBlock* m_percentHeightContainer;
 };
 
 // LayoutBox implements the full CSS box model.
 //
 // LayoutBoxModelObject only introduces some abstractions for LayoutInline and
 // LayoutBox. The logic for the model is in LayoutBox, e.g. the storage for the
 // rectangle and offset forming the CSS box (m_frameRect) and the getters for
 // the different boxes.
 //
 // LayoutBox is also the uppermost class to support scrollbars, however the
@@ skipping 751 matching lines @@
 
     void setIntrinsicContentLogicalHeight(LayoutUnit intrinsicContentLogicalHeight) const { m_intrinsicContentLogicalHeight = intrinsicContentLogicalHeight; }
 
     bool canRenderBorderImage() const;
 
     void mapLocalToContainer(const LayoutBoxModelObject* paintInvalidationContainer, TransformState&, MapCoordinatesFlags = ApplyContainerFlip, bool* wasFixed = nullptr, const PaintInvalidationState* = nullptr) const override;
     void mapAbsoluteToLocalPoint(MapCoordinatesFlags, TransformState&) const override;
 
     void clearPreviousPaintInvalidationRects() override;
 
+    LayoutBlock* positionedContainer() const { return m_rareData ? m_rareData->m_positionedContainer : nullptr; }
+    void setPositionedContainer(LayoutBlock*);
+    void removeFromPositionedContainer();
+
+    LayoutBlock* percentHeightContainer() const { return m_rareData ? m_rareData->m_percentHeightContainer : nullptr; }
+    void setPercentHeightContainer(LayoutBlock*);
+    void removeFromPercentHeightContainer();
+    void clearPercentHeightDescendants();
+
 protected:
     void willBeDestroyed() override;
 
     void styleWillChange(StyleDifference, const ComputedStyle& newStyle) override;
     void styleDidChange(StyleDifference, const ComputedStyle* oldStyle) override;
     void updateFromStyle() override;
 
     // Returns false if it could not cheaply compute the extent (e.g. fixed background), in which case the returned rect may be incorrect.
     // FIXME: make this a const method once the LayoutBox reference in BoxPainter is const.
     bool getBackgroundPaintedExtent(LayoutRect&) const;
@@ skipping 18 matching lines @@
         const LayoutRect& oldBounds, const LayoutPoint& oldPositionFromPaintInvalidationContainer,
         const LayoutRect& newBounds, const LayoutPoint& newPositionFromPaintInvalidationContainer) const override;
     void incrementallyInvalidatePaint(const LayoutBoxModelObject& paintInvalidationContainer, const LayoutRect& oldBounds, const LayoutRect& newBounds, const LayoutPoint& positionFromPaintInvalidationContainer) override;
 
     PaintInvalidationReason invalidatePaintIfNeeded(PaintInvalidationState&, const LayoutBoxModelObject& paintInvalidationContainer) override;
     void invalidatePaintOfSubtreesIfNeeded(PaintInvalidationState& childPaintInvalidationState) override;
 
     bool hasNonCompositedScrollbars() const final;
     void excludeScrollbars(LayoutRect&, OverlayScrollbarSizeRelevancy = IgnoreOverlayScrollbarSize) const;
 
+    LayoutBoxRareData* rareData() const { return m_rareData.get(); }
+    LayoutBoxRareData& ensureRareData()
+    {
+        if (!m_rareData)
+            m_rareData = adoptPtr(createRareData());

[esprehn, 2016/01/06 19:37:25]

adoptPtr should be at the creation site, not around a virtual call.

[Xianzhu, 2016/01/06 20:49:07]

Done.

+        return *m_rareData.get();
+    }
+    virtual LayoutBoxRareData* createRareData() { return new LayoutBoxRareData; }

[esprehn, 2016/01/06 19:37:25]

PassOwnPtr, you should never leak like this.

[Xianzhu, 2016/01/06 20:49:07]

Done.

+
 private:
     bool mustInvalidateBackgroundOrBorderPaintOnHeightChange() const;
     bool mustInvalidateBackgroundOrBorderPaintOnWidthChange() const;
     inline bool mustInvalidateFillLayersPaintOnWidthChange(const FillLayer&) const;
 
     void invalidatePaintRectClippedByOldAndNewBounds(const LayoutBoxModelObject& paintInvalidationContainer, const LayoutRect&, const LayoutRect& oldBounds, const LayoutRect& newBounds);
 
     void updateShapeOutsideInfoAfterStyleChange(const ComputedStyle&, const ComputedStyle* oldStyle);
     void updateGridPositionAfterStyleChange(const ComputedStyle*);
 
@@ skipping 30 matching lines @@
     // This function calculates the preferred widths for an object.
     //
     // This function is only expected to be called if
     // the boolean preferredLogicalWidthsDirty is true. It also MUST clear the
     // boolean before returning.
     //
     // See INTRINSIC SIZES / PREFERRED LOGICAL WIDTHS in LayoutObject.h for more
     // details about those widths.
     virtual void computePreferredLogicalWidths() { clearPreferredLogicalWidthsDirty(); }
 
-    LayoutBoxRareData& ensureRareData()
-    {
-        if (!m_rareData)
-            m_rareData = adoptPtr(new LayoutBoxRareData());
-        return *m_rareData.get();
-    }
-
     bool needToSavePreviousBoxSizes();
     void savePreviousBoxSizesIfNeeded();
     LayoutSize computePreviousBorderBoxSize(const LayoutSize& previousBoundsSize) const;
 
     bool logicalHeightComputesAsNone(SizeType) const;
 
     bool isBox() const = delete; // This will catch anyone doing an unnecessary check.
 
     void frameRectChanged()
     {
@@ skipping 110 matching lines @@
         if (UNLIKELY(inlineBoxWrapper() != nullptr))
             deleteLineBoxWrapper();
     }
 
     ensureRareData().m_inlineBoxWrapper = boxWrapper;
 }
 
 } // namespace blink
 
 #endif // LayoutBox_h