third_party/WebKit/Source/core/style/GridCoordinate.h

   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 GridCoordinate_h
  32 #define GridCoordinate_h
  33
  34 #include "core/style/GridResolvedPosition.h"
  35 #include "wtf/FastAllocBase.h"
  36 #include "wtf/HashMap.h"
  37 #include "wtf/PassOwnPtr.h"
  38 #include "wtf/text/WTFString.h"
  39 #include <algorithm>
  40
  41 namespace blink {
  42
  43 // Recommended maximum size for both explicit and implicit grids.
  44 const size_t kGridMaxTracks = 1000000;
  45
  46 // A span in a single direction (either rows or columns). Note that |resolvedInitialPosition|
  47 // and |resolvedFinalPosition| are grid areas' indexes, NOT grid lines'. Iterating over the
  48 // span should include both |resolvedInitialPosition| and |resolvedFinalPosition| to be correct.
  49 struct GridSpan {
  50     WTF_MAKE_FAST_ALLOCATED(GridSpan);
  51 public:
  52     static PassOwnPtr<GridSpan> create(const GridResolvedPosition& resolvedInitialPosition, const GridResolvedPosition& resolvedFinalPosition)
  53     {
  54         return adoptPtr(new GridSpan(resolvedInitialPosition, resolvedFinalPosition));
  55     }
  56
  57     static PassOwnPtr<GridSpan> createWithSpanAgainstOpposite(const GridResolvedPosition& resolvedOppositePosition, const GridPosition& position, GridPositionSide side)
  58     {
  59         // 'span 1' is contained inside a single grid track regardless of the direction.
  60         // That's why the CSS span value is one more than the offset we apply.
  61         size_t positionOffset = position.spanPosition() - 1;
  62         if (side == ColumnStartSide || side == RowStartSide) {
  63             GridResolvedPosition initialResolvedPosition = GridResolvedPosition(std::max<int>(0, resolvedOppositePosition.toInt() - positionOffset));
  64             return GridSpan::create(initialResolvedPosition, resolvedOppositePosition);
  65         }
  66
  67         return GridSpan::create(resolvedOppositePosition, GridResolvedPosition(resolvedOppositePosition.toInt() + positionOffset));
  68     }
  69
  70     static PassOwnPtr<GridSpan> createWithNamedSpanAgainstOpposite(const GridResolvedPosition& resolvedOppositePosition, const GridPosition& position, GridPositionSide side, const Vector<size_t>& gridLines)
  71     {
  72         if (side == RowStartSide || side == ColumnStartSide)
  73             return createWithInitialNamedSpanAgainstOpposite(resolvedOppositePosition, position, gridLines);
  74
  75         return createWithFinalNamedSpanAgainstOpposite(resolvedOppositePosition, position, gridLines);
  76     }
  77
  78     static PassOwnPtr<GridSpan> createWithInitialNamedSpanAgainstOpposite(const GridResolvedPosition& resolvedOppositePosition, const GridPosition& position, const Vector<size_t>& gridLines)
  79     {
  80         // The grid line inequality needs to be strict (which doesn't match the after / end case) because |resolvedOppositePosition|
  81         // is already converted to an index in our grid representation (ie one was removed from the grid line to account for the side).
  82         size_t firstLineBeforeOppositePositionIndex = 0;
  83         const size_t* firstLineBeforeOppositePosition = std::lower_bound(gridLines.begin(), gridLines.end(), resolvedOppositePosition.toInt());
  84         if (firstLineBeforeOppositePosition != gridLines.end()) {
  85             if (*firstLineBeforeOppositePosition > resolvedOppositePosition.toInt() && firstLineBeforeOppositePosition != gridLines.begin())
  86                 --firstLineBeforeOppositePosition;
  87
  88             firstLineBeforeOppositePositionIndex = firstLineBeforeOppositePosition - gridLines.begin();
  89         }
  90
  91         size_t gridLineIndex = std::max<int>(0, firstLineBeforeOppositePositionIndex - position.spanPosition() + 1);
  92         GridResolvedPosition resolvedGridLinePosition = GridResolvedPosition(gridLines[gridLineIndex]);
  93         if (resolvedGridLinePosition > resolvedOppositePosition)
  94             resolvedGridLinePosition = resolvedOppositePosition;
  95         return GridSpan::create(resolvedGridLinePosition, resolvedOppositePosition);
  96     }
  97
  98     static PassOwnPtr<GridSpan> createWithFinalNamedSpanAgainstOpposite(const GridResolvedPosition& resolvedOppositePosition, const GridPosition& position, const Vector<size_t>& gridLines)
  99     {
 100         size_t firstLineAfterOppositePositionIndex = gridLines.size() - 1;
 101         const size_t* firstLineAfterOppositePosition = std::upper_bound(gridLines.begin(), gridLines.end(), resolvedOppositePosition.toInt());
 102         if (firstLineAfterOppositePosition != gridLines.end())
 103             firstLineAfterOppositePositionIndex = firstLineAfterOppositePosition - gridLines.begin();
 104
 105         size_t gridLineIndex = std::min(gridLines.size() - 1, firstLineAfterOppositePositionIndex + position.spanPosition() - 1);
 106         GridResolvedPosition resolvedGridLinePosition = GridResolvedPosition::adjustGridPositionForAfterEndSide(gridLines[gridLineIndex]);
 107         if (resolvedGridLinePosition < resolvedOppositePosition)
 108             resolvedGridLinePosition = resolvedOppositePosition;
 109         return GridSpan::create(resolvedOppositePosition, resolvedGridLinePosition);
 110     }
 111
 112     GridSpan(const GridResolvedPosition& resolvedInitialPosition, const GridResolvedPosition& resolvedFinalPosition)
 113         : resolvedInitialPosition(std::min(resolvedInitialPosition.toInt(), kGridMaxTracks - 1))
 114         , resolvedFinalPosition(std::min(resolvedFinalPosition.toInt(), kGridMaxTracks))
 115     {
 116         ASSERT(resolvedInitialPosition <= resolvedFinalPosition);
 117     }
 118
 119     bool operator==(const GridSpan& o) const
 120     {
 121         return resolvedInitialPosition == o.resolvedInitialPosition && resolvedFinalPosition == o.resolvedFinalPosition;
 122     }
 123
 124     size_t integerSpan() const
 125     {
 126         return resolvedFinalPosition.toInt() - resolvedInitialPosition.toInt() + 1;
 127     }
 128
 129     GridResolvedPosition resolvedInitialPosition;
 130     GridResolvedPosition resolvedFinalPosition;
 131
 132     typedef GridResolvedPosition iterator;
 133
 134     iterator begin() const
 135     {
 136         return resolvedInitialPosition;
 137     }
 138
 139     iterator end() const
 140     {
 141         return resolvedFinalPosition.next();
 142     }
 143 };
 144
 145 // This represents a grid area that spans in both rows' and columns' direction.
 146 struct GridCoordinate {
 147     WTF_MAKE_FAST_ALLOCATED(GridCoordinate);
 148 public:
 149     // HashMap requires a default constuctor.
 150     GridCoordinate()
 151         : columns(0, 0)
 152         , rows(0, 0)
 153     {
 154     }
 155
 156     GridCoordinate(const GridSpan& r, const GridSpan& c)
 157         : columns(c)
 158         , rows(r)
 159     {
 160     }
 161
 162     bool operator==(const GridCoordinate& o) const
 163     {
 164         return columns == o.columns && rows == o.rows;
 165     }
 166
 167     bool operator!=(const GridCoordinate& o) const
 168     {
 169         return !(*this == o);
 170     }
 171
 172     GridResolvedPosition positionForSide(GridPositionSide side) const
 173     {
 174         switch (side) {
 175         case ColumnStartSide:
 176             return columns.resolvedInitialPosition;
 177         case ColumnEndSide:
 178             return columns.resolvedFinalPosition;
 179         case RowStartSide:
 180             return rows.resolvedInitialPosition;
 181         case RowEndSide:
 182             return rows.resolvedFinalPosition;
 183         }
 184         ASSERT_NOT_REACHED();
 185         return 0;
 186     }
 187
 188     GridSpan columns;
 189     GridSpan rows;
 190 };
 191
 192 typedef HashMap<String, GridCoordinate> NamedGridAreaMap;
 193
 194 } // namespace blink
 195
 196 #endif // GridCoordinate_h