Google Docs spreadsheet tiles render very slowly (because of event region painting)
[WebKit-https.git] / Source / WebCore / rendering / LogicalSelectionOffsetCaches.h
1 /*
2  * Copyright (C) 2013 Apple Inc. All rights reserved.
3  *
4  * This library is free software; you can redistribute it and/or
5  * modify it under the terms of the GNU Library General Public
6  * License as published by the Free Software Foundation; either
7  * version 2 of the License, or (at your option) any later version.
8  *
9  * This library is distributed in the hope that it will be useful,
10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
12  * Library General Public License for more details.
13  *
14  * You should have received a copy of the GNU Library General Public License
15  * along with this library; see the file COPYING.LIB.  If not, write to
16  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
17  * Boston, MA 02110-1301, USA.
18  *
19  */
20
21 #pragma once
22
23 #include "RenderBlock.h"
24
25 namespace WebCore {
26
27 class LogicalSelectionOffsetCaches {
28 public:
29     class ContainingBlockInfo {
30     public:
31         ContainingBlockInfo()
32             : m_hasFloatsOrFragmentedFlows(false)
33             , m_cachedLogicalLeftSelectionOffset(false)
34             , m_cachedLogicalRightSelectionOffset(false)
35         { }
36
37         void setBlock(RenderBlock* block, const LogicalSelectionOffsetCaches* cache, bool parentCacheHasFloatsOrFragmentedFlows = false)
38         {
39             m_block = block;
40             bool blockHasFloatsOrFragmentedFlows = m_block ? (m_block->containsFloats() || m_block->enclosingFragmentedFlow()) : false;
41             m_hasFloatsOrFragmentedFlows = parentCacheHasFloatsOrFragmentedFlows || m_hasFloatsOrFragmentedFlows || blockHasFloatsOrFragmentedFlows;
42             m_cache = cache;
43             m_cachedLogicalLeftSelectionOffset = false;
44             m_cachedLogicalRightSelectionOffset = false;
45         }
46
47         LayoutUnit logicalLeftSelectionOffset(RenderBlock& rootBlock, LayoutUnit position) const
48         {
49             ASSERT(m_cache);
50             if (m_hasFloatsOrFragmentedFlows || !m_cachedLogicalLeftSelectionOffset) {
51                 m_cachedLogicalLeftSelectionOffset = true;
52                 m_logicalLeftSelectionOffset = m_block ? m_block->logicalLeftSelectionOffset(rootBlock, position, *m_cache) : 0_lu;
53             } else
54                 ASSERT(m_logicalLeftSelectionOffset == (m_block ? m_block->logicalLeftSelectionOffset(rootBlock, position, *m_cache) : 0_lu));
55             return m_logicalLeftSelectionOffset;
56         }
57
58         LayoutUnit logicalRightSelectionOffset(RenderBlock& rootBlock, LayoutUnit position) const
59         {
60             ASSERT(m_cache);
61             if (m_hasFloatsOrFragmentedFlows || !m_cachedLogicalRightSelectionOffset) {
62                 m_cachedLogicalRightSelectionOffset = true;
63                 m_logicalRightSelectionOffset = m_block ? m_block->logicalRightSelectionOffset(rootBlock, position, *m_cache) : 0_lu;
64             } else
65                 ASSERT(m_logicalRightSelectionOffset == (m_block ? m_block->logicalRightSelectionOffset(rootBlock, position, *m_cache) : 0_lu));
66             return m_logicalRightSelectionOffset;
67         }
68
69         RenderBlock* block() const { return m_block; }
70         const LogicalSelectionOffsetCaches* cache() const { return m_cache; }
71         bool hasFloatsOrFragmentedFlows() const { return m_hasFloatsOrFragmentedFlows; }
72
73     private:
74         RenderBlock* m_block { nullptr };
75         const LogicalSelectionOffsetCaches* m_cache { nullptr };
76         bool m_hasFloatsOrFragmentedFlows : 1;
77         mutable bool m_cachedLogicalLeftSelectionOffset : 1;
78         mutable bool m_cachedLogicalRightSelectionOffset : 1;
79         mutable LayoutUnit m_logicalLeftSelectionOffset;
80         mutable LayoutUnit m_logicalRightSelectionOffset;
81         
82     };
83
84     explicit LogicalSelectionOffsetCaches(RenderBlock& rootBlock)
85     {
86 #if ENABLE(TEXT_SELECTION)
87         // FIXME: We should either move this assertion to the caller (if applicable) or structure the code
88         // such that we can remove this assertion.
89         ASSERT(rootBlock.isSelectionRoot());
90 #endif
91         // LogicalSelectionOffsetCaches should not be used on an orphaned tree.
92         m_containingBlockForFixedPosition.setBlock(rootBlock.containingBlockForFixedPosition(), nullptr);
93         m_containingBlockForAbsolutePosition.setBlock(rootBlock.containingBlockForAbsolutePosition(), nullptr);
94         m_containingBlockForInflowPosition.setBlock(rootBlock.containingBlockForObjectInFlow(), nullptr);
95     }
96
97     LogicalSelectionOffsetCaches(RenderBlock& block, const LogicalSelectionOffsetCaches& cache)
98         : m_containingBlockForFixedPosition(cache.m_containingBlockForFixedPosition)
99         , m_containingBlockForAbsolutePosition(cache.m_containingBlockForAbsolutePosition)
100     {
101         if (block.canContainFixedPositionObjects())
102             m_containingBlockForFixedPosition.setBlock(&block, &cache, cache.m_containingBlockForFixedPosition.hasFloatsOrFragmentedFlows());
103
104         if (block.canContainAbsolutelyPositionedObjects() && !block.isRenderInline() && !block.isAnonymousBlock())
105             m_containingBlockForAbsolutePosition.setBlock(&block, &cache, cache.m_containingBlockForAbsolutePosition.hasFloatsOrFragmentedFlows());
106
107         m_containingBlockForInflowPosition.setBlock(&block, &cache, cache.m_containingBlockForInflowPosition.hasFloatsOrFragmentedFlows());
108     }
109
110     const ContainingBlockInfo& containingBlockInfo(RenderBlock& block) const
111     {
112         auto position = block.style().position();
113         if (position == PositionType::Fixed) {
114             ASSERT(block.containingBlock() == m_containingBlockForFixedPosition.block());
115             return m_containingBlockForFixedPosition;
116         }
117         if (position == PositionType::Absolute) {
118             ASSERT(block.containingBlock() == m_containingBlockForAbsolutePosition.block());
119             return m_containingBlockForAbsolutePosition;
120         }
121         ASSERT(block.containingBlock() == m_containingBlockForInflowPosition.block());
122         return m_containingBlockForInflowPosition;
123     }
124
125 private:
126     ContainingBlockInfo m_containingBlockForFixedPosition;
127     ContainingBlockInfo m_containingBlockForAbsolutePosition;
128     ContainingBlockInfo m_containingBlockForInflowPosition;
129 };
130
131 } // namespace WebCore