Recompute overflow after transform changes

Source/core/rendering/RenderBlock.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 4831 matching lines @@
 RenderBlockFlow* RenderBlock::createAnonymousColumnSpanWithParentRenderer(const RenderObject* parent)
 {
     RefPtr<RenderStyle> newStyle = RenderStyle::createAnonymousStyleWithDisplay(parent->style(), BLOCK);
     newStyle->setColumnSpan(ColumnSpanAll);
 
     RenderBlockFlow* newBox = RenderBlockFlow::createAnonymous(&parent->document());
     newBox->setStyle(newStyle.release());
     return newBox;
 }
 
+bool RenderBlock::recalcChildOverflowAfterStyleChange()
+{
+    ASSERT(childNeedsOverflowRecalcAfterStyleChange());
+    setChildNeedsOverflowRecalcAfterStyleChange(false);
+
+    bool childrenOverflowChanged = false;
+
+    if (childrenInline()) {
+        ListHashSet<RootInlineBox*> lineBoxes;
+        for (InlineWalker walker(this); !walker.atEnd(); walker.advance()) {
+            RenderObject* renderer = walker.current();
+            if (renderer->isOutOfFlowPositioned() || !renderer->needsOverflowRecalcAfterStyleChange())
+                continue;
+
+            RenderBlock* block = toRenderBlock(renderer);
+            if (!block->recalcOverflowAfterStyleChange())
+                continue;
+
+            childrenOverflowChanged = true;
+            if (InlineBox* inlineBoxWrapper = block->inlineBoxWrapper())
+                lineBoxes.add(&inlineBoxWrapper->root());
+        }
+
+        // FIXME: Glyph overflow will get lost in this case, but not really a big deal.
+        GlyphOverflowAndFallbackFontsMap textBoxDataMap;
+        for (ListHashSet<RootInlineBox*>::const_iterator it = lineBoxes.begin(); it != lineBoxes.end(); ++it) {
+            RootInlineBox* box = *it;
+            box->computeOverflow(box->lineTop(), box->lineBottom(), textBoxDataMap);
+        }
+    } else {
+        for (RenderBox* box = firstChildBox(); box; box = box->nextSiblingBox()) {
+            if (box->isOutOfFlowPositioned() || !box->needsOverflowRecalcAfterStyleChange())
+                continue;
+
+            RenderBlock* block = toRenderBlock(box);
+            if (!block->recalcOverflowAfterStyleChange())
+                continue;

[ojan, 2014/04/19 02:19:30]

These 6 lines of code are identical to the ones in the loop above. Maybe move to
a static helper function?

[trchen, 2014/04/19 05:08:21]

Sounds reasonable to me. Will do it.

+
+            childrenOverflowChanged = true;
+        }
+    }
+
+    TrackedRendererListHashSet* positionedDescendants = positionedObjects();
+    if (!positionedDescendants)
+        return childrenOverflowChanged;
+
+    TrackedRendererListHashSet::iterator end = positionedDescendants->end();
+    for (TrackedRendererListHashSet::iterator it = positionedDescendants->begin(); it != end; ++it) {
+        RenderBox* box = *it;
+
+        if (!box->needsOverflowRecalcAfterStyleChange())
+            continue;
+        RenderBlock* block = toRenderBlock(box);
+        if (!block->recalcOverflowAfterStyleChange() || box->style()->position() == FixedPosition)
+            continue;
+
+        childrenOverflowChanged = true;
+    }
+    return childrenOverflowChanged;
+}
+
+bool RenderBlock::recalcOverflowAfterStyleChange()
+{
+    ASSERT(needsOverflowRecalcAfterStyleChange());
+
+    bool childrenOverflowChanged = false;
+    if (childNeedsOverflowRecalcAfterStyleChange())
+        childrenOverflowChanged = recalcChildOverflowAfterStyleChange();
+
+    if (!selfNeedsOverflowRecalcAfterStyleChange() && !childrenOverflowChanged)
+        return false;
+
+    setSelfNeedsOverflowRecalcAfterStyleChange(false);
+    // If the current block needs layout, overflow will be recalculated during
+    // layout time anyway. We can safely exit here.
+    if (needsLayout())
+        return false;
+
+    LayoutUnit oldClientAfterEdge = hasRenderOverflow() ? m_overflow->layoutClientAfterEdge() : clientLogicalBottom();
+    computeOverflow(oldClientAfterEdge, true);
+
+    if (hasOverflowClip())
+        layer()->scrollableArea()->updateAfterOverflowRecalc();
+
+    return !hasOverflowClip();
+}
+
 #ifndef NDEBUG
 void RenderBlock::checkPositionedObjectsNeedLayout()
 {
     if (!gPositionedDescendantsMap)
         return;
 
     if (TrackedRendererListHashSet* positionedDescendantSet = positionedObjects()) {
         TrackedRendererListHashSet::const_iterator end = positionedDescendantSet->end();
         for (TrackedRendererListHashSet::const_iterator it = positionedDescendantSet->begin(); it != end; ++it) {
             RenderBox* currBox = *it;
             ASSERT(!currBox->needsLayout());
         }
     }
 }
 
 void RenderBlock::showLineTreeAndMark(const InlineBox* markedBox1, const char* markedLabel1, const InlineBox* markedBox2, const char* markedLabel2, const RenderObject* obj) const
 {
     showRenderObject();
     for (const RootInlineBox* root = firstRootBox(); root; root = root->nextRootBox())
         root->showLineTreeAndMark(markedBox1, markedLabel1, markedBox2, markedLabel2, obj, 1);
 }
 
 #endif
 
 } // namespace WebCore