Detect a change in border that affects a positioned object's height or position

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

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2007 David Smith (catfish.man@gmail.com)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) Research In Motion Limited 2010. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
@@ skipping 87 matching lines @@
 // the middle of recomputing the style so we can't rely on any of its
 // information), which is why it's easier to just update it for every layout.
 static TrackedDescendantsMap* gPositionedDescendantsMap = nullptr;
 static TrackedContainerMap* gPositionedContainerMap = nullptr;
 
 // This map keeps track of the descendants whose 'height' is percentage associated
 // with a containing block. Like |gPositionedDescendantsMap|, it is also recomputed
 // for every layout (see the comment above about why).
 static TrackedDescendantsMap* gPercentHeightDescendantsMap = nullptr;
 
 typedef WTF::HashSet<LayoutBlock*> DelayedUpdateScrollInfoSet;

[mstensho (USE GERRIT), 2016/02/22 10:05:19]

I've mentioned this quite a few times already:

Can you PLEASE submit master rebases and your own changes as separate patches?

It's impossible for me to figure out what *you* did here and what *they* did
here.

 static int gDelayUpdateScrollInfo = 0;
 static DelayedUpdateScrollInfoSet* gDelayedUpdateScrollInfoSet = nullptr;
 
 LayoutBlock::LayoutBlock(ContainerNode* node)
     : LayoutBox(node)
     , m_hasMarginBeforeQuirk(false)
     , m_hasMarginAfterQuirk(false)
     , m_beingDestroyed(false)
     , m_hasMarkupTruncation(false)
     , m_widthAvailableToChildrenChanged(false)
+    , m_heightAvailableToChildrenChanged(false)
     , m_hasOnlySelfCollapsingChildren(false)
     , m_descendantsWithFloatsMarkedForLayout(false)
     , m_hasPositionedObjects(false)
     , m_hasPercentHeightDescendants(false)
 {
     // LayoutBlockFlow calls setChildrenInline(true).
     // By default, subclasses do not have inline children.
 }
 
 void LayoutBlock::removeFromGlobalMaps()
@@ skipping 98 matching lines @@
             // Remove our fixed positioned descendants from their current containing block.
             // They will be inserted into our positioned objects list during layout.
             if (LayoutBlock* cb = containerForFixedPosition())
                 cb->removePositionedObjects(this, NewContainingBlock);
         }
     }
 
     LayoutBox::styleWillChange(diff, newStyle);
 }
 
-static bool borderOrPaddingLogicalWidthChanged(const ComputedStyle& oldStyle, const ComputedStyle& newStyle)
+enum LogicalExtent { LogicalWidth, LogicalHeight };
+static bool borderOrPaddingLogicalDimensionChanged(const ComputedStyle& oldStyle, const ComputedStyle& newStyle, LogicalExtent logicalExtent)
 {
-    if (newStyle.isHorizontalWritingMode()) {
+    if (newStyle.isHorizontalWritingMode() == (logicalExtent == LogicalWidth)) {
         return oldStyle.borderLeftWidth() != newStyle.borderLeftWidth()
             || oldStyle.borderRightWidth() != newStyle.borderRightWidth()
             || oldStyle.paddingLeft() != newStyle.paddingLeft()
             || oldStyle.paddingRight() != newStyle.paddingRight();
     }
 
     return oldStyle.borderTopWidth() != newStyle.borderTopWidth()
         || oldStyle.borderBottomWidth() != newStyle.borderBottomWidth()
         || oldStyle.paddingTop() != newStyle.paddingTop()
         || oldStyle.paddingBottom() != newStyle.paddingBottom();
@@ skipping 22 matching lines @@
             if (LayoutBlock* cb = containingBlock())
                 cb->removePositionedObjects(this, NewContainingBlock);
         }
     }
 
     if (TextAutosizer* textAutosizer = document().textAutosizer())
         textAutosizer->record(this);
 
     propagateStyleToAnonymousChildren(true);
 
-    // It's possible for our border/padding to change, but for the overall logical width of the block to
+    // It's possible for our border/padding to change, but for the overall logical width or height of the block to
     // end up being the same. We keep track of this change so in layoutBlock, we can know to set relayoutChildren=true.
-    m_widthAvailableToChildrenChanged |= oldStyle && diff.needsFullLayout() && needsLayout() && borderOrPaddingLogicalWidthChanged(*oldStyle, newStyle);
+    m_widthAvailableToChildrenChanged |= oldStyle && diff.needsFullLayout() && needsLayout() && borderOrPaddingLogicalDimensionChanged(*oldStyle, newStyle, LogicalWidth);
+    m_heightAvailableToChildrenChanged |= oldStyle && diff.needsFullLayout() && needsLayout() && borderOrPaddingLogicalDimensionChanged(*oldStyle, newStyle, LogicalHeight);
 }
 
 void LayoutBlock::invalidatePaintOfSubtreesIfNeeded(PaintInvalidationState& childPaintInvalidationState)
 {
     LayoutBox::invalidatePaintOfSubtreesIfNeeded(childPaintInvalidationState);
 
     // Take care of positioned objects. This is required as PaintInvalidationState keeps a single clip rect.
     if (TrackedLayoutBoxListHashSet* positionedObjects = this->positionedObjects()) {
         for (auto* box : *positionedObjects) {
 
@@ skipping 590 matching lines @@
 
     // It's safe to check for control clip here, since controls can never be table cells.
     // If we have a lightweight clip, there can never be any overflow from children.
     if (hasControlClip() && m_overflow)
         clearLayoutOverflow();
 
     invalidateBackgroundObscurationStatus();
 
     if (needsScrollAnchoring)
         scrollableArea()->scrollAnchor().restore();
+
+    m_heightAvailableToChildrenChanged = false;
 }
 
 bool LayoutBlock::widthAvailableToChildrenHasChanged()
 {
+    // TODO(robhogan): Does m_widthAvailableToChildrenChanged always get reset when it needs to?

[mstensho (USE GERRIT), 2016/02/22 10:05:19]

To answer your rhetorical question: No! :)

Yeah, I think this is a suitable place for the TODO. I think it's problematic
that you have to ask if the flag is set just in order to be able to reset it.
Just look at what updateLogicalWidthAndColumnWidth() does.

     bool widthAvailableToChildrenHasChanged = m_widthAvailableToChildrenChanged;
     m_widthAvailableToChildrenChanged = false;
 
     // If we use border-box sizing, have percentage padding, and our parent has changed width then the width available to our children has changed even
     // though our own width has remained the same.
     widthAvailableToChildrenHasChanged |= style()->boxSizing() == BORDER_BOX && needsPreferredWidthsRecalculation() && view()->layoutState()->containingBlockLogicalWidthChanged();
 
     return widthAvailableToChildrenHasChanged;
 }
 
@@ skipping 79 matching lines @@
     addVisualOverflow(LayoutRect(inflatedRect));
 }
 
 bool LayoutBlock::createsNewFormattingContext() const
 {
     return isInlineBlockOrInlineTable() || isFloatingOrOutOfFlowPositioned() || hasOverflowClip() || isFlexItemIncludingDeprecated()
         || style()->specifiesColumns() || isLayoutFlowThread() || isTableCell() || isTableCaption() || isFieldset() || isWritingModeRoot()
         || isDocumentElement() || isColumnSpanAll() || isGridItem() || style()->containsPaint();
 }
 
+bool static changeInAvailableLogicalHeightAffectsChild(LayoutBlock* parent, LayoutBox& child)

[mstensho (USE GERRIT), 2016/02/22 10:05:19]

"bool static"? Can you really say that? Shouldn't it be "static bool"? Could
even say "static inline bool".

+{
+    if (parent->style()->boxSizing() != BORDER_BOX)
+        return false;
+    return parent->style()->isHorizontalWritingMode() && !child.style()->isHorizontalWritingMode();
+}
+
 void LayoutBlock::updateBlockChildDirtyBitsBeforeLayout(bool relayoutChildren, LayoutBox& child)
 {
     if (child.isOutOfFlowPositioned()) {
         // It's rather useless to mark out-of-flow children at this point. We may not be their
         // containing block (and if we are, it's just pure luck), so this would be the wrong place
         // for it. Furthermore, it would cause trouble for out-of-flow descendants of column
         // spanners, if the containing block is outside the spanner but inside the multicol container.
         return;
     }
     // FIXME: Technically percentage height objects only need a relayout if their percentage isn't going to be turned into
     // an auto value. Add a method to determine this, so that we can avoid the relayout.
     bool hasRelativeLogicalHeight = child.hasRelativeLogicalHeight()
         || (child.isAnonymous() && this->hasRelativeLogicalHeight())
         || child.stretchesToViewport();
-    if (relayoutChildren || (hasRelativeLogicalHeight && !isLayoutView())) {
+    if (relayoutChildren || (hasRelativeLogicalHeight && !isLayoutView())
+        || (m_heightAvailableToChildrenChanged && changeInAvailableLogicalHeightAffectsChild(this, child))) {
         child.setChildNeedsLayout(MarkOnlyThis);
 
         // If the child has percentage padding or an embedded content box, we also need to invalidate the childs pref widths.
         if (child.needsPreferredWidthsRecalculation())
             child.setPreferredLogicalWidthsDirty(MarkOnlyThis);
     }
 }
 
 void LayoutBlock::simplifiedNormalFlowLayout()
 {
@@ skipping 176 matching lines @@
         SubtreeLayoutScope layoutScope(*positionedObject);
         // A fixed position element with an absolute positioned ancestor has no way of knowing if the latter has changed position. So
         // if this is a fixed position element, mark it for layout if it has an abspos ancestor and needs to move with that ancestor, i.e.
         // it has static position.
         markFixedPositionObjectForLayoutIfNeeded(positionedObject, layoutScope);
         if (info == LayoutOnlyFixedPositionedObjects) {
             positionedObject->layoutIfNeeded();
             continue;
         }
 
-        if (!positionedObject->normalChildNeedsLayout() && (relayoutChildren || needsLayoutDueToStaticPosition(positionedObject)))
+        if (!positionedObject->normalChildNeedsLayout() && (relayoutChildren || m_heightAvailableToChildrenChanged || needsLayoutDueToStaticPosition(positionedObject)))
             layoutScope.setChildNeedsLayout(positionedObject);
 
         // If relayoutChildren is set and the child has percentage padding or an embedded content box, we also need to invalidate the childs pref widths.
         if (relayoutChildren && positionedObject->needsPreferredWidthsRecalculation())
             positionedObject->setPreferredLogicalWidthsDirty(MarkOnlyThis);
 
         LayoutUnit logicalTopEstimate;
         bool needsBlockDirectionLocationSetBeforeLayout = isPaginated && positionedObject->paginationBreakability() != ForbidBreaks;
         if (needsBlockDirectionLocationSetBeforeLayout) {
             // Out-of-flow objects are normally positioned after layout (while in-flow objects are
@@ skipping 1628 matching lines @@
 void LayoutBlock::showLineTreeAndMark(const InlineBox* markedBox1, const char* markedLabel1, const InlineBox* markedBox2, const char* markedLabel2, const LayoutObject* obj) const
 {
     showLayoutObject();
     for (const RootInlineBox* root = firstRootBox(); root; root = root->nextRootBox())
         root->showLineTreeAndMark(markedBox1, markedLabel1, markedBox2, markedLabel2, obj, 1);
 }
 
 #endif
 
 } // namespace blink