Paint collapsed borders of a table as one display item

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

 /*
  * Copyright (C) 1997 Martin Jones (mjones@kde.org)
  *           (C) 1997 Torben Weis (weis@kde.org)
  *           (C) 1998 Waldo Bastian (bastian@kde.org)
  *           (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2003, 2004, 2005, 2006, 2009, 2010 Apple Inc.
  *               All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
@@ skipping 11 matching lines @@
  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  * Boston, MA 02110-1301, USA.
  */
 
 #ifndef LayoutTable_h
 #define LayoutTable_h
 
 #include "core/CSSPropertyNames.h"
 #include "core/CoreExport.h"
 #include "core/layout/LayoutBlock.h"
+#include "core/paint/PaintResult.h"
 #include "core/style/CollapsedBorderValue.h"
+#include "platform/graphics/paint/CullRect.h"
 #include "wtf/Vector.h"
 #include <memory>
 
 namespace blink {
 
 class LayoutTableCol;
 class LayoutTableCaption;
 class LayoutTableCell;
 class LayoutTableSection;
 class TableLayoutAlgorithm;
@@ skipping 325 matching lines @@
       SkipEmptySectionsValue = DoNotSkipEmptySections) const;
   LayoutTableSection* sectionBelow(
       const LayoutTableSection*,
       SkipEmptySectionsValue = DoNotSkipEmptySections) const;
 
   LayoutTableCell* cellAbove(const LayoutTableCell*) const;
   LayoutTableCell* cellBelow(const LayoutTableCell*) const;
   LayoutTableCell* cellBefore(const LayoutTableCell*) const;
   LayoutTableCell* cellAfter(const LayoutTableCell*) const;
 
-  typedef Vector<CollapsedBorderValue> CollapsedBorderValues;
   void invalidateCollapsedBorders();
 
   bool hasSections() const { return m_head || m_foot || m_firstBody; }
 
   void recalcSectionsIfNeeded() const {
     if (m_needsSectionRecalc)
       recalcSections();
   }
 
   static LayoutTable* createAnonymousWithParent(const LayoutObject*);
   LayoutBox* createAnonymousBoxWithSameTypeAs(
       const LayoutObject* parent) const override {
     return createAnonymousWithParent(parent);
   }
 
   const BorderValue& tableStartBorderAdjoiningCell(
       const LayoutTableCell*) const;
   const BorderValue& tableEndBorderAdjoiningCell(const LayoutTableCell*) const;
 
   void addCaption(const LayoutTableCaption*);
   void removeCaption(const LayoutTableCaption*);
   void addColumn(const LayoutTableCol*);
   void removeColumn(const LayoutTableCol*);
 
   void paintBoxDecorationBackground(const PaintInfo&,
                                     const LayoutPoint&) const final;
 
   void paintMask(const PaintInfo&, const LayoutPoint&) const final;
 
-  const CollapsedBorderValues& collapsedBorders() const {
-    ASSERT(m_collapsedBordersValid);
-    return m_collapsedBorders;
+  struct CollapsedBordersInfo {
+    explicit CollapsedBordersInfo(const Vector<CollapsedBorderValue>& values)
+        : values(std::move(values)) {}
+
+    PaintResult lastPaintResult = FullyPainted;
+    CullRect lastPaintRect;
+    const Vector<CollapsedBorderValue> values;
+  };
+
+  bool hasCollapsedBorders() const {
+    DCHECK(m_collapsedBordersValid);
+    DCHECK(!m_collapsedBordersInfo || collapseBorders());
+    return !!m_collapsedBordersInfo;
+  }
+  CollapsedBordersInfo& getCollapsedBordersInfo() const {
+    DCHECK(hasCollapsedBorders());
+    return *m_collapsedBordersInfo;
   }
 
   void subtractCaptionRect(LayoutRect&) const;
 
   bool isLogicalWidthAuto() const;
 
   // When table headers are repeated, we need to know the offset from the block
   // start of the fragmentation context to the first occurrence of the table
   // header.
   LayoutUnit blockOffsetToFirstRepeatableHeader() const {
@@ skipping 122 matching lines @@
   // As the algorithm is dependent on the style, this field is nullptr before
   // the first style is applied in styleDidChange().
   std::unique_ptr<TableLayoutAlgorithm> m_tableLayout;
 
   // A sorted list of all unique border values that we want to paint.
   //
   // Collapsed borders are SUPER EXPENSIVE to compute. The reason is that we
   // need to compare a cells border against all the adjoining cells, rows,
   // row groups, column, column groups and table. Thus we cache them in this
   // field.
-  CollapsedBorderValues m_collapsedBorders;
+  std::unique_ptr<CollapsedBordersInfo> m_collapsedBordersInfo;
   bool m_collapsedBordersValid : 1;
 
   mutable bool m_hasColElements : 1;
   mutable bool m_needsSectionRecalc : 1;
 
   bool m_columnLogicalWidthChanged : 1;
   mutable bool m_columnLayoutObjectsValid : 1;
   mutable unsigned m_noCellColspanAtLeast;
   unsigned calcNoCellColspanAtLeast() const {
     for (unsigned c = 0; c < numEffectiveColumns(); c++) {
@@ skipping 18 matching lines @@
   if (m_firstBody)
     return m_firstBody;
   return m_foot;
 }
 
 DEFINE_LAYOUT_OBJECT_TYPE_CASTS(LayoutTable, isTable());
 
 }  // namespace blink
 
 #endif  // LayoutTable_h