Implement a Hit Test Cache.

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 2140 matching lines @@
 {
     LayoutPoint adjustedLocation(accumulatedOffset + location());
     LayoutSize localOffset = toLayoutSize(adjustedLocation);
 
     if (!isLayoutView()) {
         // Check if we need to do anything at all.
         // If we have clipping, then we can't have any spillout.
         LayoutRect overflowBox = hasOverflowClip() ? borderBoxRect() : visualOverflowRect();
         flipForWritingMode(overflowBox);
         overflowBox.moveBy(adjustedLocation);
-        if (!locationInContainer.intersects(overflowBox))
+        if (!locationInContainer.intersects(overflowBox)) {
+            result.shrinkValidityRect(overflowBox);
             return false;
+        }
     }
 
     if ((hitTestAction == HitTestBlockBackground || hitTestAction == HitTestChildBlockBackground)
         && visibleToHitTestRequest(result.hitTestRequest())
         && isPointInOverflowControl(result, locationInContainer.point(), adjustedLocation)) {
-        updateHitTestResult(result, locationInContainer.point() - localOffset);
+        // TODO(dtapuska): calculate the layout rect
+
+        updateHitTestResult(result, locationInContainer.point() - localOffset, result.validityRect());
         // FIXME: isPointInOverflowControl() doesn't handle rect-based tests yet.
         if (!result.addNodeToListBasedTestResult(nodeForHitTest(), locationInContainer))
             return true;
     }
 
     if (style()->clipPath()) {
         switch (style()->clipPath()->type()) {
         case ClipPathOperation::SHAPE: {
             ShapeClipPathOperation* clipPath = toShapeClipPathOperation(style()->clipPath());
             // FIXME: handle marginBox etc.
             if (!clipPath->path(borderBoxRect()).contains(FloatPoint(locationInContainer.point() - localOffset), clipPath->windRule()))
                 return false;
             break;
         }
         case ClipPathOperation::REFERENCE:
             // FIXME: handle REFERENCE
             break;
         }
     }
 
     // If we have clipping, then we can't have any spillout.
     bool useOverflowClip = hasOverflowClip() && !hasSelfPaintingLayer();
     bool useClip = (hasControlClip() || useOverflowClip);
     bool checkChildren = !useClip;
     if (!checkChildren) {
+        LayoutRect clipRect;
         if (hasControlClip()) {
-            checkChildren = locationInContainer.intersects(controlClipRect(adjustedLocation));
+            clipRect = controlClipRect(adjustedLocation);
+            checkChildren = locationInContainer.intersects(clipRect);
         } else {
-            LayoutRect clipRect = overflowClipRect(adjustedLocation, IncludeOverlayScrollbarSize);
+            clipRect = overflowClipRect(adjustedLocation, IncludeOverlayScrollbarSize);
             if (style()->hasBorderRadius())
                 checkChildren = locationInContainer.intersects(style()->getRoundedBorderFor(clipRect));
             else
                 checkChildren = locationInContainer.intersects(clipRect);
         }
+        if (!checkChildren)
+            result.shrinkValidityRect(clipRect);
+        else
+            result.intersectValidityRect(clipRect);
     }
     if (checkChildren) {
         // Hit test descendants first.
         LayoutSize scrolledOffset(localOffset);
         if (hasOverflowClip())
             scrolledOffset -= scrolledContentOffset();
 
         // Hit test contents if we don't have columns.
         if (!hasColumns()) {
             if (hitTestContents(result, locationInContainer, toLayoutPoint(scrolledOffset), hitTestAction)) {
-                updateHitTestResult(result, flipForWritingMode(locationInContainer.point() - localOffset));
+                // TODO(dtapuska): calculate the layout rect
+
+                updateHitTestResult(result, flipForWritingMode(locationInContainer.point() - localOffset), result.validityRect());
                 return true;
             }
             if (hitTestAction == HitTestFloat && hitTestFloats(result, locationInContainer, toLayoutPoint(scrolledOffset)))
                 return true;
         } else if (hitTestColumns(result, locationInContainer, toLayoutPoint(scrolledOffset), hitTestAction)) {
-            updateHitTestResult(result, flipForWritingMode(locationInContainer.point() - localOffset));
+            // TODO(dtapuska): calculate the layout rect
+            updateHitTestResult(result, flipForWritingMode(locationInContainer.point() - localOffset), result.validityRect());
             return true;
         }
     }
 
     // Check if the point is outside radii.
     if (style()->hasBorderRadius()) {
         LayoutRect borderRect = borderBoxRect();
         borderRect.moveBy(adjustedLocation);
         FloatRoundedRect border = style()->getRoundedBorderFor(borderRect);
-        if (!locationInContainer.intersects(border))
+        if (!locationInContainer.intersects(border)) {
+            result.shrinkValidityRect(borderRect);
             return false;
+        }
     }
 
     // Now hit test our background
     if (hitTestAction == HitTestBlockBackground || hitTestAction == HitTestChildBlockBackground) {
         LayoutRect boundsRect(adjustedLocation, size());
         if (visibleToHitTestRequest(result.hitTestRequest()) && locationInContainer.intersects(boundsRect)) {
-            updateHitTestResult(result, flipForWritingMode(locationInContainer.point() - localOffset));
+            updateHitTestResult(result, flipForWritingMode(locationInContainer.point() - localOffset), boundsRect);
             if (!result.addNodeToListBasedTestResult(nodeForHitTest(), locationInContainer, boundsRect))
                 return true;
         }
+        result.shrinkValidityRect(boundsRect);
     }
 
     return false;
 }
 
 class ColumnRectIterator {
     WTF_MAKE_NONCOPYABLE(ColumnRectIterator);
 public:
     ColumnRectIterator(const LayoutBlock& block)
         : m_block(block)
@@ skipping 1229 matching lines @@
 }
 
 void LayoutBlock::childBecameNonInline(LayoutObject*)
 {
     makeChildrenNonInline();
     if (isAnonymousBlock() && parent() && parent()->isLayoutBlock())
         toLayoutBlock(parent())->removeLeftoverAnonymousBlock(this);
     // |this| may be dead here
 }
 
-void LayoutBlock::updateHitTestResult(HitTestResult& result, const LayoutPoint& point)
+void LayoutBlock::updateHitTestResult(HitTestResult& result, const LayoutPoint& point, const LayoutRect& rect)
 {
     if (result.innerNode())
         return;
 
+    result.intersectValidityRect(rect);
     if (Node* n = nodeForHitTest())
         result.setNodeAndPosition(n, point);
 }
 
 // An inline-block uses its inlineBox as the inlineBoxWrapper,
 // so the firstChild() is nullptr if the only child is an empty inline-block.
 inline bool LayoutBlock::isInlineBoxWrapperActuallyChild() const
 {
     return isInlineBlockOrInlineTable() && !size().isEmpty() && node() && editingIgnoresContent(node());
 }
@@ skipping 416 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