1/*
2 * Copyright (C) 2012 Apple 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
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 *    notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 *    notice, this list of conditions and the following disclaimer in the
11 *    documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26
27#ifndef RenderMultiColumnBlock_h
28#define RenderMultiColumnBlock_h
29
30#include "RenderBlock.h"
31
32namespace WebCore {
33
34class RenderMultiColumnFlowThread;
35
36class RenderMultiColumnBlock : public RenderBlock {
37public:
38    RenderMultiColumnBlock(Element*);
39
40    LayoutUnit columnHeightAvailable() const { return m_columnHeightAvailable; }
41
42    LayoutUnit columnWidth() const { return m_columnWidth; }
43    unsigned columnCount() const { return m_columnCount; }
44
45    RenderMultiColumnFlowThread* flowThread() const { return m_flowThread; }
46
47    bool requiresBalancing() const { return !m_columnHeightAvailable; }
48
49private:
50    virtual bool isRenderMultiColumnBlock() const { return true; }
51
52    virtual const char* renderName() const;
53
54    virtual RenderObject* layoutSpecialExcludedChild(bool relayoutChildren) OVERRIDE;
55
56    virtual void styleDidChange(StyleDifference, const RenderStyle*) OVERRIDE;
57
58    virtual bool updateLogicalWidthAndColumnWidth() OVERRIDE;
59    virtual void checkForPaginationLogicalHeightChange(LayoutUnit& pageLogicalHeight, bool& pageLogicalHeightChanged, bool& hasSpecifiedPageLogicalHeight) OVERRIDE;
60    virtual bool relayoutForPagination(bool hasSpecifiedPageLogicalHeight, LayoutUnit pageLogicalHeight, LayoutStateMaintainer&) OVERRIDE;
61
62    virtual void addChild(RenderObject* newChild, RenderObject* beforeChild = 0) OVERRIDE;
63
64    void computeColumnCountAndWidth();
65
66    void ensureColumnSets();
67
68    RenderMultiColumnFlowThread* m_flowThread;
69    unsigned m_columnCount;   // The default column count/width that are based off our containing block width. These values represent only the default,
70    LayoutUnit m_columnWidth; // since a multi-column block that is split across variable width pages or regions will have different column counts and widths in each.
71                              // These values will be cached (eventually) for multi-column blocks.
72    LayoutUnit m_columnHeightAvailable; // Total height available to columns, or 0 if auto.
73    bool m_inBalancingPass; // Set when relayouting for column balancing.
74};
75
76inline RenderMultiColumnBlock* toRenderMultiColumnBlock(RenderObject* object)
77{
78    ASSERT_WITH_SECURITY_IMPLICATION(!object || object->isRenderMultiColumnBlock());
79    return static_cast<RenderMultiColumnBlock*>(object);
80}
81
82inline const RenderMultiColumnBlock* toRenderMultiColumnBlock(const RenderObject* object)
83{
84    ASSERT_WITH_SECURITY_IMPLICATION(!object || object->isRenderMultiColumnBlock());
85    return static_cast<const RenderMultiColumnBlock*>(object);
86}
87
88// This will catch anyone doing an unnecessary cast.
89void toRenderMultiColumnBlock(const RenderMultiColumnBlock*);
90
91} // namespace WebCore
92
93#endif // RenderMultiColumnBlock_h
94
95