*** DO NOT LAND *** Attempt to understand Regions complexity

Source/core/rendering/RenderBlockLineLayout.cpp

Index: Source/core/rendering/RenderBlockLineLayout.cpp
diff --git a/Source/core/rendering/RenderBlockLineLayout.cpp b/Source/core/rendering/RenderBlockLineLayout.cpp
index f2b9bed38c58a47b8d2f2f54c48d1012b9e967fa..134ed4e9ab302ad100bd893d27367922b9096a6d 100644
--- a/Source/core/rendering/RenderBlockLineLayout.cpp
+++ b/Source/core/rendering/RenderBlockLineLayout.cpp
@@ -25,10 +25,8 @@
 #include "core/rendering/FastTextAutosizer.h"
 #include "core/rendering/LayoutRectRecorder.h"
 #include "core/rendering/RenderCounter.h"
-#include "core/rendering/RenderFlowThread.h"
 #include "core/rendering/RenderLayer.h"
 #include "core/rendering/RenderListMarker.h"
-#include "core/rendering/RenderRegion.h"
 #include "core/rendering/RenderRubyRun.h"
 #include "core/rendering/RenderView.h"
 #include "core/rendering/TrailingFloatsRootInlineBox.h"
@@ -1104,9 +1102,6 @@ static inline void pushShapeContentOverflowBelowTheContentBox(RenderBlockFlow* b
 
 void RenderBlockFlow::updateShapeAndSegmentsForCurrentLine(ShapeInsideInfo*& shapeInsideInfo, const LayoutSize& logicalOffsetFromShapeContainer, LineLayoutState& layoutState)
 {
-    if (layoutState.flowThread())
-        return updateShapeAndSegmentsForCurrentLineInFlowThread(shapeInsideInfo, layoutState);
-
     if (!shapeInsideInfo)
         return;
 
@@ -1120,87 +1115,6 @@ void RenderBlockFlow::updateShapeAndSegmentsForCurrentLine(ShapeInsideInfo*& sha
     pushShapeContentOverflowBelowTheContentBox(this, shapeInsideInfo, lineTop, lineHeight);
 }
 
-void RenderBlockFlow::updateShapeAndSegmentsForCurrentLineInFlowThread(ShapeInsideInfo*& shapeInsideInfo, LineLayoutState& layoutState)
-{
-    ASSERT(layoutState.flowThread());
-
-    RenderRegion* currentRegion = regionAtBlockOffset(logicalHeight());
-    if (!currentRegion || !currentRegion->logicalHeight())
-        return;
-
-    shapeInsideInfo = currentRegion->shapeInsideInfo();
-
-    RenderRegion* nextRegion = 0;
-    if (!currentRegion->isLastRegion()) {
-        RenderRegionList regionList = layoutState.flowThread()->renderRegionList();
-        RenderRegionList::const_iterator it = regionList.find(currentRegion);
-        nextRegion = *(++it);
-    }
-
-    // We only want to deal regions with shapes, so we check if the next region has a shape
-    if (!shapeInsideInfo && nextRegion && !nextRegion->shapeInsideInfo())
-        return;
-
-    LayoutUnit lineHeight = this->lineHeight(layoutState.lineInfo().isFirstLine(), isHorizontalWritingMode() ? HorizontalLine : VerticalLine, PositionOfInteriorLineBoxes);
-    LayoutUnit logicalLineTopInFlowThread = logicalHeight() + offsetFromLogicalTopOfFirstPage();
-    LayoutUnit logicalLineBottomInFlowThread = logicalLineTopInFlowThread + lineHeight;
-    LayoutUnit logicalRegionTopInFlowThread = currentRegion->logicalTopForFlowThreadContent();
-    LayoutUnit logicalRegionBottomInFlowThread = logicalRegionTopInFlowThread + currentRegion->logicalHeight() - currentRegion->borderAndPaddingBefore() - currentRegion->borderAndPaddingAfter();
-
-    LayoutUnit shapeBottomInFlowThread = LayoutUnit::max();
-    if (shapeInsideInfo)
-        shapeBottomInFlowThread = shapeInsideInfo->shapeLogicalBottom() + currentRegion->logicalTopForFlowThreadContent();
-
-    bool lineOverLapsWithShapeBottom = shapeBottomInFlowThread < logicalLineBottomInFlowThread;
-    bool lineTopAdjustedIntoNextRegion = layoutState.adjustedLogicalLineTop() >= currentRegion->logicalHeight();
-    bool lineOverLapsWithRegionBottom = logicalLineBottomInFlowThread > logicalRegionBottomInFlowThread || lineTopAdjustedIntoNextRegion;
-    bool overFlowsToNextRegion = nextRegion && (lineOverLapsWithShapeBottom || lineOverLapsWithRegionBottom);
-
-    // If the line is between two shapes/regions we position the line to the top of the next shape/region
-    if (overFlowsToNextRegion) {
-        ASSERT(currentRegion != nextRegion);
-        LayoutUnit deltaToNextRegion = logicalRegionBottomInFlowThread - logicalLineTopInFlowThread;
-        setLogicalHeight(logicalHeight() + deltaToNextRegion);
-
-        currentRegion = nextRegion;
-        shapeInsideInfo = currentRegion->shapeInsideInfo();
-
-        logicalLineTopInFlowThread = logicalHeight() + offsetFromLogicalTopOfFirstPage();
-        logicalLineBottomInFlowThread = logicalLineTopInFlowThread + lineHeight;
-        logicalRegionTopInFlowThread = currentRegion->logicalTopForFlowThreadContent();
-        logicalRegionBottomInFlowThread = logicalRegionTopInFlowThread + currentRegion->logicalHeight() - currentRegion->borderAndPaddingBefore() - currentRegion->borderAndPaddingAfter();
-
-        if (lineTopAdjustedIntoNextRegion)
-            layoutState.setAdjustedLogicalLineTop(0);
-    }
-
-    if (!shapeInsideInfo)
-        return;
-
-    bool isFirstLineInRegion = logicalLineBottomInFlowThread <= (logicalRegionTopInFlowThread + lineHeight);
-    bool isFirstLineAdjusted = (logicalLineTopInFlowThread - logicalRegionTopInFlowThread) < (layoutState.adjustedLogicalLineTop() - currentRegion->borderAndPaddingBefore());
-    // We position the first line to the top of the shape in the region or to the previously adjusted position in the shape
-    if (isFirstLineInRegion || isFirstLineAdjusted) {
-        LayoutUnit shapeTopOffset = layoutState.adjustedLogicalLineTop();
-        if (!shapeTopOffset && (shapeInsideInfo->shapeLogicalTop() > 0))
-            shapeTopOffset = shapeInsideInfo->shapeLogicalTop();
-
-        LayoutUnit shapePositionInFlowThread = currentRegion->logicalTopForFlowThreadContent() + shapeTopOffset;
-        LayoutUnit shapeTopLineTopDelta = shapePositionInFlowThread - logicalLineTopInFlowThread - currentRegion->borderAndPaddingBefore();
-
-        setLogicalHeight(logicalHeight() + shapeTopLineTopDelta);
-        logicalLineTopInFlowThread += shapeTopLineTopDelta;
-        layoutState.setAdjustedLogicalLineTop(0);
-    }
-
-    LayoutUnit lineTop = logicalLineTopInFlowThread - currentRegion->logicalTopForFlowThreadContent() + currentRegion->borderAndPaddingBefore();
-    // FIXME: Shape inside on a region does not yet take into account its padding for nested flow blocks
-    shapeInsideInfo->updateSegmentsForLine(LayoutSize(0, lineTop), lineHeight);
-
-    if (currentRegion->isLastRegion())
-        pushShapeContentOverflowBelowTheContentBox(this, shapeInsideInfo, lineTop, lineHeight);
-}
-
 bool RenderBlockFlow::adjustLogicalLineTopAndLogicalHeightIfNeeded(ShapeInsideInfo* shapeInsideInfo, LayoutUnit absoluteLogicalTop, LineLayoutState& layoutState, InlineBidiResolver& resolver, FloatingObject* lastFloatFromPreviousLine, InlineIterator& end, WordMeasurements& wordMeasurements)
 {
     LayoutUnit adjustedLogicalLineTop = adjustLogicalLineTop(shapeInsideInfo, resolver.position(), end, wordMeasurements);
@@ -1219,11 +1133,6 @@ bool RenderBlockFlow::adjustLogicalLineTopAndLogicalHeightIfNeeded(ShapeInsideIn
 
     LayoutUnit newLogicalHeight = adjustedLogicalLineTop - absoluteLogicalTop;
 
-    if (layoutState.flowThread()) {
-        layoutState.setAdjustedLogicalLineTop(adjustedLogicalLineTop);
-        newLogicalHeight = logicalHeight();
-    }
-
     end = restartLayoutRunsAndFloatsInRange(logicalHeight(), newLogicalHeight, lastFloatFromPreviousLine, resolver, end);
     return true;
 }
@@ -1252,8 +1161,6 @@ void RenderBlockFlow::layoutRunsAndFloatsInRange(LineLayoutState& layoutState, I
         // Begin layout at the logical top of our shape inside.
         if (logicalHeight() + logicalOffsetFromShapeContainer.height() < shapeInsideInfo->shapeLogicalTop()) {
             LayoutUnit logicalHeight = shapeInsideInfo->shapeLogicalTop() - logicalOffsetFromShapeContainer.height();
-            if (layoutState.flowThread())
-                logicalHeight -= shapeInsideInfo->owner()->borderAndPaddingBefore();
             setLogicalHeight(logicalHeight);
         }
     }
@@ -1337,7 +1244,7 @@ void RenderBlockFlow::layoutRunsAndFloatsInRange(LineLayoutState& layoutState, I
 
                 if (paginated) {
                     LayoutUnit adjustment = 0;
-                    adjustLinePositionForPagination(lineBox, adjustment, layoutState.flowThread());
+                    adjustLinePositionForPagination(lineBox, adjustment);
                     if (adjustment) {
                         LayoutUnit oldLineWidth = availableLogicalWidthForLine(oldLogicalHeight, layoutState.lineInfo().isFirstLine());
                         lineBox->adjustBlockDirectionPosition(adjustment);
@@ -1353,9 +1260,6 @@ void RenderBlockFlow::layoutRunsAndFloatsInRange(LineLayoutState& layoutState, I
 
                         setLogicalHeight(lineBox->lineBottomWithLeading());
                     }
-
-                    if (layoutState.flowThread())
-                        updateRegionForLine(lineBox);
                 }
             }
         }
@@ -1468,14 +1372,12 @@ void RenderBlockFlow::linkToEndLineIfNeeded(LineLayoutState& layoutState)
                 line->attachLine();
                 if (paginated) {
                     delta -= line->paginationStrut();
-                    adjustLinePositionForPagination(line, delta, layoutState.flowThread());
+                    adjustLinePositionForPagination(line, delta);
                 }
                 if (delta) {
                     layoutState.updateRepaintRangeFromBox(line, delta);
                     line->adjustBlockDirectionPosition(delta);
                 }
-                if (layoutState.flowThread())
-                    updateRegionForLine(line);
                 if (Vector<RenderBox*>* cleanLineFloats = line->floatsPtr()) {
                     Vector<RenderBox*>::iterator end = cleanLineFloats->end();
                     for (Vector<RenderBox*>::iterator f = cleanLineFloats->begin(); f != end; ++f) {
@@ -1509,12 +1411,10 @@ void RenderBlockFlow::linkToEndLineIfNeeded(LineLayoutState& layoutState)
             LayoutUnit blockLogicalHeight = logicalHeight();
             trailingFloatsLineBox->alignBoxesInBlockDirection(blockLogicalHeight, textBoxDataMap, verticalPositionCache);
             trailingFloatsLineBox->setLineTopBottomPositions(blockLogicalHeight, blockLogicalHeight, blockLogicalHeight, blockLogicalHeight);
-            trailingFloatsLineBox->setPaginatedLineWidth(availableLogicalWidthForContent(blockLogicalHeight));
+            trailingFloatsLineBox->setPaginatedLineWidth(availableLogicalWidthForContent());
             LayoutRect logicalLayoutOverflow(0, blockLogicalHeight, 1, bottomLayoutOverflow - blockLogicalHeight);
             LayoutRect logicalVisualOverflow(0, blockLogicalHeight, 1, bottomVisualOverflow - blockLogicalHeight);
             trailingFloatsLineBox->setOverflowFromLogicalRects(logicalLayoutOverflow, logicalVisualOverflow, trailingFloatsLineBox->lineTop(), trailingFloatsLineBox->lineBottom());
-            if (layoutState.flowThread())
-                updateRegionForLine(trailingFloatsLineBox);
         }
 
         const FloatingObjectSet& floatingObjectSet = m_floatingObjects->set();
@@ -1557,13 +1457,10 @@ void RenderBlockFlow::layoutInlineChildren(bool relayoutChildren, LayoutUnit& re
     if (view()->layoutState() && view()->layoutState()->lineGrid() == this)
         layoutLineGridBox();
 
-    RenderFlowThread* flowThread = flowThreadContainingBlock();
-    bool clearLinesForPagination = firstLineBox() && flowThread && !flowThread->hasRegions();
-
     // Figure out if we should clear out our line boxes.
     // FIXME: Handle resize eventually!
-    bool isFullLayout = !firstLineBox() || selfNeedsLayout() || relayoutChildren || clearLinesForPagination;
-    LineLayoutState layoutState(isFullLayout, repaintLogicalTop, repaintLogicalBottom, flowThread);
+    bool isFullLayout = !firstLineBox() || selfNeedsLayout() || relayoutChildren;
+    LineLayoutState layoutState(isFullLayout, repaintLogicalTop, repaintLogicalBottom);
 
     if (isFullLayout)
         lineBoxes()->deleteLineBoxes();
@@ -1698,12 +1595,12 @@ RootInlineBox* RenderBlockFlow::determineStartPosition(LineLayoutState& layoutSt
         size_t floatIndex = 0;
         for (curr = firstRootBox(); curr && !curr->isDirty(); curr = curr->nextRootBox()) {
             if (paginated) {
-                if (lineWidthForPaginatedLineChanged(curr, 0, layoutState.flowThread())) {
+                if (lineWidthForPaginatedLineChanged(curr, 0)) {
                     curr->markDirty();
                     break;
                 }
                 paginationDelta -= curr->paginationStrut();
-                adjustLinePositionForPagination(curr, paginationDelta, layoutState.flowThread());
+                adjustLinePositionForPagination(curr, paginationDelta);
                 if (paginationDelta) {
                     if (containsFloats() || !layoutState.floats().isEmpty()) {
                         // FIXME: Do better eventually.  For now if we ever shift because of pagination and floats are present just go to a full layout.
@@ -1714,8 +1611,6 @@ RootInlineBox* RenderBlockFlow::determineStartPosition(LineLayoutState& layoutSt
                     layoutState.updateRepaintRangeFromBox(curr, paginationDelta);
                     curr->adjustBlockDirectionPosition(paginationDelta);
                 }
-                if (layoutState.flowThread())
-                    updateRegionForLine(curr);
             }
 
             // If a new float has been inserted before this line or before its last known float, just do a full layout.
@@ -1848,24 +1743,6 @@ bool RenderBlockFlow::checkPaginationAndFloatsAtEndLine(LineLayoutState& layoutS
 {
     LayoutUnit lineDelta = logicalHeight() - layoutState.endLineLogicalTop();
 
-    bool paginated = view()->layoutState() && view()->layoutState()->isPaginated();
-    if (paginated && layoutState.flowThread()) {
-        // Check all lines from here to the end, and see if the hypothetical new position for the lines will result
-        // in a different available line width.
-        for (RootInlineBox* lineBox = layoutState.endLine(); lineBox; lineBox = lineBox->nextRootBox()) {
-            if (paginated) {
-                // This isn't the real move we're going to do, so don't update the line box's pagination
-                // strut yet.
-                LayoutUnit oldPaginationStrut = lineBox->paginationStrut();
-                lineDelta -= oldPaginationStrut;
-                adjustLinePositionForPagination(lineBox, lineDelta, layoutState.flowThread());
-                lineBox->setPaginationStrut(oldPaginationStrut);
-            }
-            if (lineWidthForPaginatedLineChanged(lineBox, lineDelta, layoutState.flowThread()))
-                return false;
-        }
-    }
-
     if (!lineDelta || !m_floatingObjects)
         return true;