Avoid pathological layout on nested percent height tables

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

 /*
  * 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, 2007, 2008, 2009, 2010, 2013 Apple Inc.
  *               All rights reserved.
  * Copyright (C) 2006 Alexey Proskuryakov (ap@nypop.com)
  *
@@ skipping 48 matching lines @@
       m_firstBody(nullptr),
       m_collapsedBordersValid(false),
       m_hasColElements(false),
       m_needsSectionRecalc(false),
       m_columnLogicalWidthChanged(false),
       m_columnLayoutObjectsValid(false),
       m_noCellColspanAtLeast(0),
       m_hSpacing(0),
       m_vSpacing(0),
       m_borderStart(0),
-      m_borderEnd(0) {
+      m_borderEnd(0),
+      m_oldAvailableLogicalHeight(0) {

[mstensho (USE GERRIT), 2017/02/20 13:01:31]

No need (actually surprisingly expensive if you do) to initialize LayoutUnit.

   ASSERT(!childrenInline());
   m_effectiveColumnPositions.fill(0, 1);
 }
 
 LayoutTable::~LayoutTable() {}
 
 void LayoutTable::styleDidChange(StyleDifference diff,
                                  const ComputedStyle* oldStyle) {
   LayoutBlock::styleDidChange(diff, oldStyle);
 
@@ skipping 358 matching lines @@
   if (!selfNeedsLayout())
     caption.setMayNeedPaintInvalidation();
 
   setLogicalHeight(logicalHeight() + caption.logicalHeight() +
                    collapsedMarginBeforeForChild(caption) +
                    collapsedMarginAfterForChild(caption));
 }
 
 void LayoutTable::layoutSection(LayoutTableSection& section,
                                 SubtreeLayoutScope& layouter,
-                                LayoutUnit logicalLeft) {
+                                LayoutUnit logicalLeft,
+                                TableHeightChangingValue tableHeightChanging) {
   section.setLogicalLocation(LayoutPoint(logicalLeft, logicalHeight()));
   if (m_columnLogicalWidthChanged)
     layouter.setChildNeedsLayout(&section);
   if (!section.needsLayout())
     markChildForPaginationRelayoutIfNeeded(section, layouter);
-  section.layoutIfNeeded();
-  int sectionLogicalHeight = section.calcRowLogicalHeight();
-  section.setLogicalHeight(LayoutUnit(sectionLogicalHeight));
+  bool neededLayout = section.needsLayout();
+  if (neededLayout)
+    section.layout();
+  if (neededLayout || tableHeightChanging == TableHeightChanging)
+    section.setLogicalHeight(LayoutUnit(section.calcRowLogicalHeight()));
+
   if (view()->layoutState()->isPaginated())
     updateFragmentationInfoForChild(section);
-  setLogicalHeight(logicalHeight() + sectionLogicalHeight);
+  setLogicalHeight(logicalHeight() + section.logicalHeight());
 }
 
 LayoutUnit LayoutTable::logicalHeightFromStyle() const {
   LayoutUnit computedLogicalHeight;
   Length logicalHeightLength = style()->logicalHeight();
   if (logicalHeightLength.isIntrinsic() ||
       (logicalHeightLength.isSpecified() && logicalHeightLength.isPositive())) {
     computedLogicalHeight =
         convertStyleLogicalHeightToComputedHeight(logicalHeightLength);
   }
@@ skipping 24 matching lines @@
 void LayoutTable::distributeExtraLogicalHeight(int extraLogicalHeight) {
   if (extraLogicalHeight <= 0)
     return;
 
   // FIXME: Distribute the extra logical height between all table sections
   // instead of giving it all to the first one.
   if (LayoutTableSection* section = firstBody())
     extraLogicalHeight -=
         section->distributeExtraLogicalHeightToRows(extraLogicalHeight);
 
-  // FIXME: We really would like to enable this ASSERT to ensure that all the
-  // extra space has been distributed.
+  // crbug.com/690087: We really would like to enable this ASSERT to ensure that
+  // all the extra space has been distributed.
   // However our current distribution algorithm does not round properly and thus
   // we can have some remaining height.
   // ASSERT(!topSection() || !extraLogicalHeight);
 }
 
 void LayoutTable::simplifiedNormalFlowLayout() {
   // FIXME: We should walk through the items in the tree in tree order to do the
   // layout here instead of walking through individual parts of the tree.
   // crbug.com/442737
   for (auto& caption : m_captions)
@@ skipping 100 matching lines @@
         borderAfter() + (collapsing ? LayoutUnit() : paddingAfter());
 
     setLogicalHeight(tableBoxLogicalTop + borderAndPaddingBefore);
 
     LayoutUnit sectionLogicalLeft = LayoutUnit(
         style()->isLeftToRightDirection() ? borderStart() : borderEnd());
     if (!collapsing) {
       sectionLogicalLeft +=
           style()->isLeftToRightDirection() ? paddingStart() : paddingEnd();
     }
+    LayoutUnit currentAvailableLogicalHeight =
+        availableLogicalHeight(IncludeMarginBorderPadding);
+    TableHeightChangingValue tableHeightChanging =
+        m_oldAvailableLogicalHeight &&
+                m_oldAvailableLogicalHeight != currentAvailableLogicalHeight
+            ? TableHeightChanging
+            : TableHeightNotChanging;
+    m_oldAvailableLogicalHeight = currentAvailableLogicalHeight;
 
     // Lay out table header group.
     if (LayoutTableSection* section = header()) {
-      layoutSection(*section, layouter, sectionLogicalLeft);
+      layoutSection(*section, layouter, sectionLogicalLeft,
+                    tableHeightChanging);
       if (state.isPaginated()) {
         // If the repeating header group allows at least one row of content,
         // then store the offset for other sections to offset their rows
         // against.
         LayoutUnit sectionLogicalHeight = section->logicalHeight();
         if (sectionLogicalHeight <
                 section->pageLogicalHeightForOffset(section->logicalTop()) &&
             section->getPaginationBreakability() != AllowAnyBreaks) {
           // Don't include any strut in the header group - we only want the
           // height from its content.
           LayoutUnit offsetForTableHeaders = sectionLogicalHeight;
           if (LayoutTableRow* row = section->firstRow())
             offsetForTableHeaders -= row->paginationStrut();
           setRowOffsetFromRepeatingHeader(offsetForTableHeaders);
         }
       }
     }
 
     // Lay out table body groups, and column groups.
     for (LayoutObject* child = firstChild(); child;
          child = child->nextSibling()) {
       if (child->isTableSection()) {
         if (child != header() && child != footer()) {
           LayoutTableSection& section = *toLayoutTableSection(child);
-          layoutSection(section, layouter, sectionLogicalLeft);
+          layoutSection(section, layouter, sectionLogicalLeft,
+                        tableHeightChanging);
         }
       } else if (child->isLayoutTableCol()) {
         child->layoutIfNeeded();
       } else {
         DCHECK(child->isTableCaption());
       }
     }
 
     // Lay out table footer.
-    if (LayoutTableSection* section = footer())
-      layoutSection(*section, layouter, sectionLogicalLeft);
+    if (LayoutTableSection* section = footer()) {
+      layoutSection(*section, layouter, sectionLogicalLeft,
+                    tableHeightChanging);
+    }
 
     setLogicalHeight(tableBoxLogicalTop + borderAndPaddingBefore);
 
     LayoutUnit computedLogicalHeight = logicalHeightFromStyle();
     LayoutUnit totalSectionLogicalHeight;
     if (topSection) {
       totalSectionLogicalHeight =
           bottomSection->logicalBottom() - topSection->logicalTop();
     }
 
@@ skipping 1019 matching lines @@
 }
 
 LayoutUnit LayoutTable::paddingRight() const {
   if (collapseBorders())
     return LayoutUnit();
 
   return LayoutBlock::paddingRight();
 }
 
 }  // namespace blink