[New Multicolumn] Preparatory work for nested multicol support.

Source/core/rendering/RenderFlowThread.cpp

 /*
  * Copyright (C) 2011 Adobe Systems Incorporated. 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.
@@ skipping 72 matching lines @@
                     if (m_regionsHaveUniformLogicalHeight && previousRegionLogicalHeight != regionLogicalHeight)
                         m_regionsHaveUniformLogicalHeight = false;
                 }
 
                 previousRegionLogicalHeight = regionLogicalHeight;
             }
         }
     }
 
     updateLogicalWidth(); // Called to get the maximum logical width for the columnSet.
-    updateRegionsFlowThreadPortionRect();
+    generateColumnSetIntervalTree();
 }
 
 void RenderFlowThread::mapRectToPaintInvalidationBacking(const LayoutLayerModelObject* paintInvalidationContainer, LayoutRect& rect, const PaintInvalidationState* paintInvalidationState) const
 {
     ASSERT(paintInvalidationContainer != this); // A flow thread should never be an invalidation container.
     rect = fragmentsBoundingBox(rect);
     RenderBlockFlow::mapRectToPaintInvalidationBacking(paintInvalidationContainer, rect, paintInvalidationState);
 }
 
 void RenderFlowThread::layout()
@@ skipping 55 matching lines @@
     return m_multiColumnSetList.first();
 }
 
 RenderRegion* RenderFlowThread::lastRegion() const
 {
     if (!hasValidRegionInfo())
         return 0;
     return m_multiColumnSetList.last();
 }
 
-void RenderFlowThread::updateRegionsFlowThreadPortionRect()
+void RenderFlowThread::generateColumnSetIntervalTree()
 {
-    LayoutUnit logicalHeight = 0;
     // FIXME: Optimize not to clear the interval all the time. This implies manually managing the tree nodes lifecycle.
     m_multiColumnSetIntervalTree.clear();
     m_multiColumnSetIntervalTree.initIfNeeded();
-    for (RenderMultiColumnSetList::iterator iter = m_multiColumnSetList.begin(); iter != m_multiColumnSetList.end(); ++iter) {
-        RenderMultiColumnSet* columnSet = *iter;
-
-        LayoutUnit columnSetLogicalWidth = columnSet->pageLogicalWidth();
-        LayoutUnit columnSetLogicalHeight = std::min<LayoutUnit>(RenderFlowThread::maxLogicalHeight() - logicalHeight, columnSet->logicalHeightInFlowThread());
-
-        LayoutRect columnSetRect(style()->direction() == LTR ? LayoutUnit() : logicalWidth() - columnSetLogicalWidth, logicalHeight, columnSetLogicalWidth, columnSetLogicalHeight);
-
-        columnSet->setFlowThreadPortionRect(isHorizontalWritingMode() ? columnSetRect : columnSetRect.transposedRect());
-
-        m_multiColumnSetIntervalTree.add(MultiColumnSetIntervalTree::createInterval(logicalHeight, logicalHeight + columnSetLogicalHeight, columnSet));
-
-        logicalHeight += columnSetLogicalHeight;
-    }
+    for (auto columnSet : m_multiColumnSetList)

[Julien - ping for review, 2015/02/11 07:25:29]

I assume this doesn't do a deep copy behind the scene?

[mstensho (USE GERRIT), 2015/02/11 09:49:55]

Correct. No copying.

+        m_multiColumnSetIntervalTree.add(MultiColumnSetIntervalTree::createInterval(columnSet->logicalTopInFlowThread(), columnSet->logicalBottomInFlowThread(), columnSet));
 }
 
 void RenderFlowThread::collectLayerFragments(LayerFragments& layerFragments, const LayoutRect& layerBoundingBox, const LayoutRect& dirtyRect)
 {
     ASSERT(!m_regionsInvalidated);
 
     for (RenderMultiColumnSetList::const_iterator iter = m_multiColumnSetList.begin(); iter != m_multiColumnSetList.end(); ++iter) {
         RenderMultiColumnSet* columnSet = *iter;
         columnSet->collectLayerFragments(layerFragments, layerBoundingBox, dirtyRect);
     }
@@ skipping 22 matching lines @@
 
 void RenderFlowThread::MultiColumnSetSearchAdapter::collectIfNeeded(const MultiColumnSetInterval& interval)
 {
     if (m_result)
         return;
     if (interval.low() <= m_offset && interval.high() > m_offset)
         m_result = interval.data();
 }
 
 } // namespace blink