File: RenderLayoutState.h

package info (click to toggle)
webkit2gtk 2.48.5-1
  • links: PTS, VCS
  • area: main
  • in suites: forky, sid
  • size: 429,764 kB
  • sloc: cpp: 3,697,587; javascript: 194,444; ansic: 169,997; python: 46,499; asm: 19,295; ruby: 18,528; perl: 16,602; xml: 4,650; yacc: 2,360; sh: 2,098; java: 1,993; lex: 1,327; pascal: 366; makefile: 298
file content (218 lines) | stat: -rw-r--r-- 8,618 bytes parent folder | download | duplicates (6)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
/*
 * Copyright (C) 2007, 2013 Apple Inc.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
 */

#pragma once

#include "LayoutRect.h"
#include "LocalFrameViewLayoutContext.h"
#include "StyleTextEdge.h"
#include <wtf/Noncopyable.h>
#include <wtf/TZoneMalloc.h>
#include <wtf/WeakPtr.h>

namespace WebCore {

class RenderBlockFlow;
class RenderBox;
class RenderElement;
class RenderFragmentedFlow;
class RenderMultiColumnFlow;
class RenderObject;

class RenderLayoutState {
    WTF_MAKE_TZONE_ALLOCATED(RenderLayoutState);
    WTF_MAKE_NONCOPYABLE(RenderLayoutState);

public:
    struct LineClamp {
        size_t maximumLines { 0 };
        bool shouldDiscardOverflow { false };
    };

    struct LegacyLineClamp {
        size_t maximumLineCount { 0 };
        size_t currentLineCount { 0 };
        std::optional<LayoutUnit> clampedContentLogicalHeight;
        SingleThreadWeakPtr<const RenderBlockFlow> clampedRenderer;
    };

    RenderLayoutState()
        : m_clipped(false)
        , m_isPaginated(false)
        , m_pageLogicalHeightChanged(false)
#if ASSERT_ENABLED
        , m_layoutDeltaXSaturated(false)
        , m_layoutDeltaYSaturated(false)
#endif
        , m_marginTrimBlockStart(false)
    {
    }
    RenderLayoutState(const LocalFrameViewLayoutContext::LayoutStateStack&, RenderBox&, const LayoutSize& offset, LayoutUnit pageHeight, bool pageHeightChanged, std::optional<LineClamp>, std::optional<LegacyLineClamp>);
    explicit RenderLayoutState(RenderElement&);

    bool isPaginated() const { return m_isPaginated; }

    // The page logical offset is the object's offset from the top of the page in the page progression
    // direction (so an x-offset in vertical text and a y-offset for horizontal text).
    LayoutUnit pageLogicalOffset(RenderBox*, LayoutUnit childLogicalOffset) const;
    
    LayoutUnit pageLogicalHeight() const { return m_pageLogicalHeight; }
    bool pageLogicalHeightChanged() const { return m_pageLogicalHeightChanged; }

    RenderBlockFlow* lineGrid() const { return m_lineGrid.get(); }
    LayoutSize lineGridOffset() const { return m_lineGridOffset; }
    LayoutSize lineGridPaginationOrigin() const { return m_lineGridPaginationOrigin; }

    LayoutSize paintOffset() const { return m_paintOffset; }
    LayoutSize layoutOffset() const { return m_layoutOffset; }

    LayoutSize pageOffset() const { return m_pageOffset; }

    bool needsBlockDirectionLocationSetBeforeLayout() const { return m_lineGrid || (m_isPaginated && m_pageLogicalHeight); }

#if ASSERT_ENABLED
    RenderElement* renderer() const { return m_renderer; }
#endif
    LayoutRect clipRect() const { return m_clipRect; }
    bool isClipped() const { return m_clipped; }

    void addLayoutDelta(LayoutSize);
    LayoutSize layoutDelta() const { return m_layoutDelta; }
#if ASSERT_ENABLED
    bool layoutDeltaMatches(LayoutSize) const;
#endif

    void setLineClamp(std::optional<LineClamp> lineClamp) { m_lineClamp = lineClamp; }
    std::optional<LineClamp> lineClamp() { return m_lineClamp; }

    void setLegacyLineClamp(std::optional<LegacyLineClamp> legacyLineClamp) { m_legacyLineClamp = legacyLineClamp; }
    std::optional<LegacyLineClamp> legacyLineClamp() const { return m_legacyLineClamp; }

    void setMarginTrimBlockStart(bool marginTrimBlockStart) { m_marginTrimBlockStart = marginTrimBlockStart; }
    bool marginTrimBlockStart() const { return m_marginTrimBlockStart; }

private:
    void computeOffsets(const RenderLayoutState& ancestor, RenderBox&, LayoutSize offset);
    void computeClipRect(const RenderLayoutState& ancestor, RenderBox&);
    // FIXME: webkit.org/b/179440 these functions should be part of the pagination code/LocalFrameViewLayoutContext.
    void computePaginationInformation(const LocalFrameViewLayoutContext::LayoutStateStack&, RenderBox&, LayoutUnit pageLogicalHeight, bool pageLogicalHeightChanged);
    void propagateLineGridInfo(const RenderLayoutState& ancestor, RenderBox&);
    void establishLineGrid(const LocalFrameViewLayoutContext::LayoutStateStack&, RenderBlockFlow&);
    void computeLineGridPaginationOrigin(const RenderMultiColumnFlow&);

    // Do not add anything apart from bitfields. See https://bugs.webkit.org/show_bug.cgi?id=100173
    bool m_clipped : 1;
    bool m_isPaginated : 1;
    // If our page height has changed, this will force all blocks to relayout.
    bool m_pageLogicalHeightChanged : 1;
#if ASSERT_ENABLED
    bool m_layoutDeltaXSaturated : 1;
    bool m_layoutDeltaYSaturated : 1;
#endif
    bool m_marginTrimBlockStart : 1 { false };

    // The current line grid that we're snapping to and the offset of the start of the grid.
    SingleThreadWeakPtr<RenderBlockFlow> m_lineGrid;

    // FIXME: Distinguish between the layout clip rect and the paint clip rect which may be larger,
    // e.g., because of composited scrolling.
    LayoutRect m_clipRect;
    
    // x/y offset from layout root. Includes in-flow positioning and scroll offsets.
    LayoutSize m_paintOffset;
    // x/y offset from layout root. Does not include in-flow positioning or scroll offsets.
    LayoutSize m_layoutOffset;
    // Transient offset from the final position of the object
    // used to ensure that repaints happen in the correct place.
    // This is a total delta accumulated from the root. 
    LayoutSize m_layoutDelta;

    // The current page height for the pagination model that encloses us.
    LayoutUnit m_pageLogicalHeight;
    // The offset of the start of the first page in the nearest enclosing pagination model.
    LayoutSize m_pageOffset;
    LayoutSize m_lineGridOffset;
    LayoutSize m_lineGridPaginationOrigin;
    std::optional<LineClamp> m_lineClamp;
    std::optional<LegacyLineClamp> m_legacyLineClamp;
#if ASSERT_ENABLED
    RenderElement* m_renderer { nullptr };
#endif
};

// Stack-based class to assist with LayoutState push/pop
class LayoutStateMaintainer {
    WTF_MAKE_NONCOPYABLE(LayoutStateMaintainer);
public:
    explicit LayoutStateMaintainer(RenderBox&, LayoutSize offset, bool disableState = false, LayoutUnit pageHeight = 0_lu, bool pageHeightChanged = false);
    ~LayoutStateMaintainer();

private:
    LocalFrameViewLayoutContext& m_context;
    bool m_paintOffsetCacheIsDisabled { false };
    bool m_didPushLayoutState { false };
};

class SubtreeLayoutStateMaintainer {
public:
    SubtreeLayoutStateMaintainer(RenderElement* subtreeLayoutRoot);
    ~SubtreeLayoutStateMaintainer();

private:
    LocalFrameViewLayoutContext* m_context { nullptr };
    bool m_didDisablePaintOffsetCache { false };
};

class LayoutStateDisabler {
    WTF_MAKE_NONCOPYABLE(LayoutStateDisabler);
public:
    LayoutStateDisabler(LocalFrameViewLayoutContext&);
    ~LayoutStateDisabler();

private:
    LocalFrameViewLayoutContext& m_context;
};

class FlexPercentResolveDisabler {
public:
    FlexPercentResolveDisabler(LocalFrameViewLayoutContext&, const RenderBox& flexItem);
    ~FlexPercentResolveDisabler();

private:
    CheckedRef<LocalFrameViewLayoutContext> m_layoutContext;
    CheckedRef<const RenderBox> m_flexItem;
};

class ContentVisibilityForceLayoutScope {
public:
    ContentVisibilityForceLayoutScope(LocalFrameViewLayoutContext&, const Element*);
    ~ContentVisibilityForceLayoutScope();

private:
    CheckedRef<LocalFrameViewLayoutContext> m_layoutContext;
    CheckedPtr<const Element> m_element;
};

} // namespace WebCore