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      1 /*
      2  * Copyright (C) 2013 Google Inc. All rights reserved.
      3  *
      4  * Redistribution and use in source and binary forms, with or without
      5  * modification, are permitted provided that the following conditions are
      6  * met:
      7  *
      8  *     * Redistributions of source code must retain the above copyright
      9  * notice, this list of conditions and the following disclaimer.
     10  *     * Redistributions in binary form must reproduce the above
     11  * copyright notice, this list of conditions and the following disclaimer
     12  * in the documentation and/or other materials provided with the
     13  * distribution.
     14  *     * Neither the name of Google Inc. nor the names of its
     15  * contributors may be used to endorse or promote products derived from
     16  * this software without specific prior written permission.
     17  *
     18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     19  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     20  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     21  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     22  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     23  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     24  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     28  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     29  */
     30 
     31 #ifndef RenderLazyBlock_h
     32 #define RenderLazyBlock_h
     33 
     34 #include "core/rendering/RenderBlock.h"
     35 
     36 namespace WebCore {
     37 
     38 class RenderLazyBlock FINAL : public RenderBlock {
     39 public:
     40     RenderLazyBlock(Element*);
     41     virtual ~RenderLazyBlock();
     42 
     43     bool isAttached() const { return m_attached; }
     44     bool isNested() const;
     45 
     46     void markForNestedLayout()
     47     {
     48         setNeedsLayout();
     49         m_isNestedLayout = true;
     50     }
     51 
     52     RenderLazyBlock* next() const { return m_next; }
     53     RenderLazyBlock* previous() const { return m_previous; }
     54 
     55     RenderBox* firstVisibleChildBox() const { return m_firstVisibleChildBox; }
     56     RenderBox* lastVisibleChildBox() const { return m_lastVisibleChildBox; }
     57 
     58 private:
     59     virtual void paintChildren(PaintInfo&, const LayoutPoint&) OVERRIDE;
     60 
     61     virtual bool isRenderLazyBlock() const OVERRIDE { return true; }
     62     virtual void willBeDestroyed() OVERRIDE;
     63     virtual void willBeRemovedFromTree() OVERRIDE;
     64     virtual void layoutBlock(bool relayoutChildren, LayoutUnit pageLogicalHeight) OVERRIDE;
     65 
     66     void layoutChildren(bool relayoutChildren);
     67 
     68     void attachLazyBlock();
     69     void detachLazyBlock();
     70 
     71     RenderLazyBlock* m_next;
     72     RenderLazyBlock* m_previous;
     73     RenderBox* m_firstVisibleChildBox;
     74     RenderBox* m_lastVisibleChildBox;
     75     bool m_attached;
     76     bool m_isNestedLayout;
     77     LayoutRect m_intersectRect;
     78     IntRect m_expandedViewportRect;
     79 };
     80 
     81 inline RenderLazyBlock* toRenderLazyBlock(RenderObject* object)
     82 {
     83     ASSERT_WITH_SECURITY_IMPLICATION(!object || object->isRenderLazyBlock());
     84     return static_cast<RenderLazyBlock*>(object);
     85 }
     86 
     87 inline const RenderLazyBlock* toRenderLazyBlock(const RenderObject* object)
     88 {
     89     ASSERT_WITH_SECURITY_IMPLICATION(!object || object->isRenderLazyBlock());
     90     return static_cast<const RenderLazyBlock*>(object);
     91 }
     92 
     93 } // namespace WebCore
     94 
     95 #endif // RenderLazyBlock_h
     96