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 PartialLayoutState_h
32 #define PartialLayoutState_h
33
34 #include "core/rendering/RenderObject.h"
35
36 namespace WebCore {
37
38 class PartialLayoutState {
39 friend class PartialLayoutDisabler;
40 public:
PartialLayoutState()41 PartialLayoutState()
42 : m_shouldStop(false)
43 , m_stopAtRenderer(0)
44 , m_disableCount(0)
45 {
46 }
47
48 // True if we plan to do a partial layout, or are in the process of stopping a partial layout.
isPartialLayout()49 bool isPartialLayout() const { return m_stopAtRenderer || m_shouldStop; }
50
isStopping()51 bool isStopping() const { return m_shouldStop; }
52 bool checkPartialLayoutComplete(const RenderObject*);
setStopAtRenderer(const RenderObject * renderer)53 void setStopAtRenderer(const RenderObject* renderer) { m_stopAtRenderer = renderer; }
reset()54 void reset() { m_shouldStop = false; m_stopAtRenderer = 0; }
55
56 private:
disable()57 void disable() { ASSERT(!m_shouldStop); m_disableCount++; }
enable()58 void enable() { ASSERT(m_disableCount > 0); m_disableCount--; }
stopAtRenderer()59 const RenderObject* stopAtRenderer() const { return m_disableCount > 0 ? 0 : m_stopAtRenderer; }
60
61 bool m_shouldStop;
62 const RenderObject* m_stopAtRenderer;
63 int m_disableCount;
64 };
65
checkPartialLayoutComplete(const RenderObject * renderer)66 inline bool PartialLayoutState::checkPartialLayoutComplete(const RenderObject* renderer)
67 {
68 if (m_shouldStop)
69 return true;
70
71 if (renderer == stopAtRenderer()) {
72 m_shouldStop = true;
73 m_stopAtRenderer = 0;
74 return true;
75 }
76
77 return false;
78 }
79
80 class PartialLayoutDisabler {
81 WTF_MAKE_NONCOPYABLE(PartialLayoutDisabler);
82 public:
83 PartialLayoutDisabler(PartialLayoutState& partialLayout, bool disable = true)
m_partialLayout(partialLayout)84 : m_partialLayout(partialLayout)
85 , m_disable(disable)
86 {
87 if (m_disable)
88 m_partialLayout.disable();
89 }
90
~PartialLayoutDisabler()91 ~PartialLayoutDisabler()
92 {
93 if (m_disable)
94 m_partialLayout.enable();
95 }
96 private:
97 PartialLayoutState& m_partialLayout;
98 bool m_disable;
99 };
100
101 } // namespace WebCore
102
103 #endif // PartialLayoutState_h
104