*** DO NOT LAND *** Measure the size and complexity of the old multicol implementation.

Source/core/rendering/LayoutState.cpp

 /*
  * Copyright (C) 2007 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
@@ skipping 15 matching lines @@
 #include "config.h"
 #include "core/rendering/LayoutState.h"
 
 #include "core/rendering/RenderInline.h"
 #include "core/rendering/RenderLayer.h"
 #include "core/rendering/RenderView.h"
 #include "platform/Partitions.h"
 
 namespace WebCore {
 
-LayoutState::LayoutState(LayoutState* prev, RenderBox* renderer, const LayoutSize& offset, LayoutUnit pageLogicalHeight, bool pageLogicalHeightChanged, ColumnInfo* columnInfo)
-    : m_columnInfo(columnInfo)
-    , m_lineGrid(0)
+LayoutState::LayoutState(LayoutState* prev, RenderBox* renderer, const LayoutSize& offset, LayoutUnit pageLogicalHeight, bool pageLogicalHeightChanged)
+    : m_lineGrid(0)
     , m_next(prev)
     , m_shapeInsideInfo(0)
 #ifndef NDEBUG
     , m_renderer(renderer)
 #endif
 {
     ASSERT(m_next);
 
     bool fixed = renderer->isOutOfFlowPositioned() && renderer->style()->position() == FixedPosition;
     if (fixed) {
@@ skipping 28 matching lines @@
         else {
             m_clipRect = clipRect;
             m_clipped = true;
         }
 
         m_paintOffset -= renderer->scrolledContentOffset();
     }
 
     // If we establish a new page height, then cache the offset to the top of the first page.
     // We can compare this later on to figure out what part of the page we're actually on,
-    if (pageLogicalHeight || m_columnInfo || renderer->isRenderFlowThread()) {
+    if (pageLogicalHeight || renderer->isRenderFlowThread()) {
         m_pageLogicalHeight = pageLogicalHeight;
         bool isFlipped = renderer->style()->isFlippedBlocksWritingMode();
         m_pageOffset = LayoutSize(m_layoutOffset.width() + (!isFlipped ? renderer->borderLeft() + renderer->paddingLeft() : renderer->borderRight() + renderer->paddingRight()),
                                m_layoutOffset.height() + (!isFlipped ? renderer->borderTop() + renderer->paddingTop() : renderer->borderBottom() + renderer->paddingBottom()));
         m_pageLogicalHeightChanged = pageLogicalHeightChanged;
     } else {
         // If we don't establish a new page height, then propagate the old page height and offset down.
         m_pageLogicalHeight = m_next->m_pageLogicalHeight;
         m_pageLogicalHeightChanged = m_next->m_pageLogicalHeightChanged;
         m_pageOffset = m_next->m_pageOffset;
 
         // Disable pagination for objects we don't support. For now this includes overflow:scroll/auto, inline blocks and
         // writing mode roots.
         if (renderer->isUnsplittableForPagination())
             m_pageLogicalHeight = 0;
     }
 
     // Propagate line grid information.
     propagateLineGridInfo(renderer);
 
-    if (!m_columnInfo)
-        m_columnInfo = m_next->m_columnInfo;
-
     if (renderer->isRenderBlock()) {
         const RenderBlock* renderBlock = toRenderBlock(renderer);
         m_shapeInsideInfo = renderBlock->shapeInsideInfo();
         if (!m_shapeInsideInfo && m_next->m_shapeInsideInfo && renderBlock->allowsShapeInsideInfoSharing(m_next->m_shapeInsideInfo->owner()))
             m_shapeInsideInfo = m_next->m_shapeInsideInfo;
     }
 
     if (!RuntimeEnabledFeatures::repaintAfterLayoutEnabled()) {
         m_layoutDelta = m_next->m_layoutDelta;
 #if !ASSERT_DISABLED
         m_layoutDeltaXSaturated = m_next->m_layoutDeltaXSaturated;
         m_layoutDeltaYSaturated = m_next->m_layoutDeltaYSaturated;
 #endif
     }
 
-    m_isPaginated = m_pageLogicalHeight || m_columnInfo || renderer->isRenderFlowThread();
-
-    if (lineGrid() && renderer->hasColumns() && renderer->style()->hasInlineColumnAxis())
-        computeLineGridPaginationOrigin(renderer);
+    m_isPaginated = m_pageLogicalHeight || renderer->isRenderFlowThread();
 
     // If we have a new grid to track, then add it to our set.
     if (renderer->style()->lineGrid() != RenderStyle::initialLineGrid() && renderer->isRenderBlockFlow())
         establishLineGrid(toRenderBlockFlow(renderer));
 
     // FIXME: <http://bugs.webkit.org/show_bug.cgi?id=13443> Apply control clip if present.
 }
 
 LayoutState::LayoutState(RenderObject* root)
     : m_clipped(false)
     , m_isPaginated(false)
     , m_pageLogicalHeightChanged(false)
 #if !ASSERT_DISABLED
     , m_layoutDeltaXSaturated(false)
     , m_layoutDeltaYSaturated(false)
 #endif
-    , m_columnInfo(0)
     , m_lineGrid(0)
     , m_next(0)
     , m_shapeInsideInfo(0)
     , m_pageLogicalHeight(0)
 #ifndef NDEBUG
     , m_renderer(root)
 #endif
 {
     RenderObject* container = root->container();
     FloatPoint absContentPoint = container->localToAbsolute(FloatPoint(), UseTransforms);
@@ skipping 10 matching lines @@
 void* LayoutState::operator new(size_t sz)
 {
     return partitionAlloc(Partitions::getRenderingPartition(), sz);
 }
 
 void LayoutState::operator delete(void* ptr)
 {
     partitionFree(ptr);
 }
 
-void LayoutState::clearPaginationInformation()
-{
-    m_pageLogicalHeight = m_next->m_pageLogicalHeight;
-    m_pageOffset = m_next->m_pageOffset;
-    m_columnInfo = m_next->m_columnInfo;
-}
-
 LayoutUnit LayoutState::pageLogicalOffset(RenderBox* child, LayoutUnit childLogicalOffset) const
 {
     if (child->isHorizontalWritingMode())
         return m_layoutOffset.height() + childLogicalOffset - m_pageOffset.height();
     return m_layoutOffset.width() + childLogicalOffset - m_pageOffset.width();
 }
 
-void LayoutState::addForcedColumnBreak(RenderBox* child, LayoutUnit childLogicalOffset)
-{
-    if (!m_columnInfo || m_columnInfo->columnHeight())
-        return;
-    m_columnInfo->addForcedBreak(pageLogicalOffset(child, childLogicalOffset));
-}
-
 void LayoutState::propagateLineGridInfo(RenderBox* renderer)
 {
     // Disable line grids for objects we don't support. For now this includes overflow:scroll/auto, inline blocks and
     // writing mode roots.
     if (!m_next || renderer->isUnsplittableForPagination())
         return;
 
     m_lineGrid = m_next->m_lineGrid;
     m_lineGridOffset = m_next->m_lineGridOffset;
     m_lineGridPaginationOrigin = m_next->m_lineGridPaginationOrigin;
@@ skipping 18 matching lines @@
                 return;
             }
         }
     }
 
     // We didn't find an already-established grid with this identifier. Our render object establishes the grid.
     m_lineGrid = block;
     m_lineGridOffset = m_layoutOffset;
 }
 
-void LayoutState::computeLineGridPaginationOrigin(RenderBox* renderer)
-{
-    // We need to cache a line grid pagination origin so that we understand how to reset the line grid
-    // at the top of each column.
-    // Get the current line grid and offset.
-    if (!lineGrid() || lineGrid()->style()->writingMode() != renderer->style()->writingMode())
-        return;
-
-    // Get the hypothetical line box used to establish the grid.
-    RootInlineBox* lineGridBox = lineGrid()->lineGridBox();
-    if (!lineGridBox)
-        return;
-
-    bool isHorizontalWritingMode = lineGrid()->isHorizontalWritingMode();
-
-    LayoutUnit lineGridBlockOffset = isHorizontalWritingMode ? lineGridOffset().height() : lineGridOffset().width();
-
-    // Now determine our position on the grid. Our baseline needs to be adjusted to the nearest baseline multiple
-    // as established by the line box.
-    // FIXME: Need to handle crazy line-box-contain values that cause the root line box to not be considered. I assume
-    // the grid should honor line-box-contain.
-    LayoutUnit gridLineHeight = lineGridBox->lineBottomWithLeading() - lineGridBox->lineTopWithLeading();
-    if (!gridLineHeight)
-        return;
-
-    LayoutUnit firstLineTopWithLeading = lineGridBlockOffset + lineGridBox->lineTopWithLeading();
-
-    if (isPaginated() && pageLogicalHeight()) {
-        LayoutUnit pageLogicalTop = renderer->isHorizontalWritingMode() ? m_pageOffset.height() : m_pageOffset.width();
-        if (pageLogicalTop > firstLineTopWithLeading) {
-            // Shift to the next highest line grid multiple past the page logical top. Cache the delta
-            // between this new value and the page logical top as the pagination origin.
-            LayoutUnit remainder = roundToInt(pageLogicalTop - firstLineTopWithLeading) % roundToInt(gridLineHeight);
-            LayoutUnit paginationDelta = gridLineHeight - remainder;
-            if (isHorizontalWritingMode)
-                m_lineGridPaginationOrigin.setHeight(paginationDelta);
-            else
-                m_lineGridPaginationOrigin.setWidth(paginationDelta);
-        }
-    }
-}
-
 } // namespace WebCore