third_party/WebKit/Source/core/layout/LayoutTableCol.h

   1 /*
   2  * Copyright (C) 1997 Martin Jones (mjones@kde.org)
   3  *           (C) 1997 Torben Weis (weis@kde.org)
   4  *           (C) 1998 Waldo Bastian (bastian@kde.org)
   5  *           (C) 1999 Lars Knoll (knoll@kde.org)
   6  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
   7  * Copyright (C) 2003, 2004, 2005, 2006, 2009 Apple Inc. All rights reserved.
   8  * Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies)
   9  *
  10  * This library is free software; you can redistribute it and/or
  11  * modify it under the terms of the GNU Library General Public
  12  * License as published by the Free Software Foundation; either
  13  * version 2 of the License, or (at your option) any later version.
  14  *
  15  * This library is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  18  * Library General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU Library General Public License
  21  * along with this library; see the file COPYING.LIB.  If not, write to
  22  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  23  * Boston, MA 02110-1301, USA.
  24  */
  25
  26 #ifndef LayoutTableCol_h
  27 #define LayoutTableCol_h
  28
  29 #include "core/layout/LayoutBox.h"
  30
  31 namespace blink {
  32
  33 class LayoutTable;
  34 class LayoutTableCell;
  35
  36 // LayoutTableCol is used to represent table column or column groups
  37 // (display: table-column and display: table-column-group).
  38 //
  39 // The reason to use the same LayoutObject is that both objects behave in a very
  40 // similar way. The main difference between the 2 is that table-column-group
  41 // allows table-column children, when table-column don't.
  42 // Note that this matches how <col> and <colgroup> map to the same class:
  43 // HTMLTableColElement.
  44 //
  45 // In HTML and CSS, table columns and colgroups don't own the cells, they are
  46 // descendants of the rows.
  47 // As such table columns and colgroups have a very limited scope in the table:
  48 // - column / cell sizing (the 'width' property)
  49 // - background painting (the 'background' property).
  50 // - border collapse resolution
  51 //   (http://www.w3.org/TR/CSS21/tables.html#border-conflict-resolution)
  52 //
  53 // See http://www.w3.org/TR/CSS21/tables.html#columns for the standard.
  54 // Note that we don't implement the "visibility: collapse" inheritance to the
  55 // cells.
  56 //
  57 // Because table columns and column groups are placeholder elements (see
  58 // previous paragraph), they are never laid out and layout() should not be
  59 // called on them.
  60 class LayoutTableCol final : public LayoutBox {
  61 public:
  62     explicit LayoutTableCol(Element*);
  63
  64     LayoutObject* firstChild() const { ASSERT(children() == virtualChildren()); return children()->firstChild(); }
  65
  66     // If you have a LayoutTableCol, use firstChild or lastChild instead.
  67     void slowFirstChild() const = delete;
  68     void slowLastChild() const = delete;
  69
  70     const LayoutObjectChildList* children() const { return &m_children; }
  71     LayoutObjectChildList* children() { return &m_children; }
  72
  73     void clearPreferredLogicalWidthsDirtyBits();
  74
  75     // The 'span' attribute in HTML.
  76     // For CSS table columns or colgroups, this is always 1.
  77     unsigned span() const { return m_span; }
  78
  79     bool isTableColumnGroupWithColumnChildren() { return firstChild(); }
  80     bool isTableColumn() const { return style()->display() == TABLE_COLUMN; }
  81     bool isTableColumnGroup() const { return style()->display() == TABLE_COLUMN_GROUP; }
  82
  83     LayoutTableCol* enclosingColumnGroup() const;
  84     LayoutTableCol* enclosingColumnGroupIfAdjacentBefore() const
  85     {
  86         if (previousSibling())
  87             return nullptr;
  88         return enclosingColumnGroup();
  89     }
  90
  91     LayoutTableCol* enclosingColumnGroupIfAdjacentAfter() const
  92     {
  93         if (nextSibling())
  94             return nullptr;
  95         return enclosingColumnGroup();
  96     }
  97
  98
  99     // Returns the next column or column-group.
 100     LayoutTableCol* nextColumn() const;
 101
 102     const BorderValue& borderAdjoiningCellStartBorder(const LayoutTableCell*) const;
 103     const BorderValue& borderAdjoiningCellEndBorder(const LayoutTableCell*) const;
 104     const BorderValue& borderAdjoiningCellBefore(const LayoutTableCell*) const;
 105     const BorderValue& borderAdjoiningCellAfter(const LayoutTableCell*) const;
 106
 107     const char* name() const override { return "LayoutTableCol"; }
 108
 109 private:
 110     LayoutObjectChildList* virtualChildren() override { return children(); }
 111     const LayoutObjectChildList* virtualChildren() const override { return children(); }
 112
 113     bool isOfType(LayoutObjectType type) const override { return type == LayoutObjectLayoutTableCol || LayoutBox::isOfType(type); }
 114     void updateFromElement() override;
 115     void computePreferredLogicalWidths() override { ASSERT_NOT_REACHED(); }
 116
 117     void insertedIntoTree() override;
 118     void willBeRemovedFromTree() override;
 119
 120     bool isChildAllowed(LayoutObject*, const ComputedStyle&) const override;
 121     bool canHaveChildren() const override;
 122     DeprecatedPaintLayerType layerTypeRequired() const override { return NoDeprecatedPaintLayer; }
 123
 124     LayoutRect clippedOverflowRectForPaintInvalidation(const LayoutBoxModelObject* paintInvalidationContainer, const PaintInvalidationState* = nullptr) const override;
 125     void imageChanged(WrappedImagePtr, const IntRect* = nullptr) override;
 126
 127     void styleDidChange(StyleDifference, const ComputedStyle* oldStyle) override;
 128
 129     LayoutTable* table() const;
 130
 131     LayoutObjectChildList m_children;
 132     unsigned m_span;
 133 };
 134
 135 DEFINE_LAYOUT_OBJECT_TYPE_CASTS(LayoutTableCol, isLayoutTableCol());
 136
 137 }
 138
 139 #endif