Moving HitTest function to DeprecatedPaintLayerStackingNode.

Source/core/paint/DeprecatedPaintLayerStackingNode.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011, 2012 Apple Inc. All rights reserved.
  *
  * Portions are Copyright (C) 1998 Netscape Communications Corporation.
  *
  * Other contributors:
  *   Robert O'Callahan <roc+@cs.cmu.edu>
  *   David Baron <dbaron@fas.harvard.edu>
  *   Christian Biesinger <cbiesinger@web.de>
  *   Randall Jesup <rjesup@wgate.com>
@@ skipping 26 matching lines @@
  * version of this file under the LGPL, indicate your decision by
  * deletingthe provisions above and replace them with the notice and
  * other provisions required by the MPL or the GPL, as the case may be.
  * If you do not delete the provisions above, a recipient may use your
  * version of this file under any of the LGPL, the MPL or the GPL.
  */
 
 #include "config.h"
 #include "core/paint/DeprecatedPaintLayerStackingNode.h"
 
+#include "core/layout/HitTestLocation.h"
+#include "core/layout/HitTestRequest.h"
+#include "core/layout/HitTestResult.h"
 #include "core/layout/LayoutView.h"
 #include "core/layout/compositing/DeprecatedPaintLayerCompositor.h"
 #include "core/paint/DeprecatedPaintLayer.h"
 #include "public/platform/Platform.h"
 
 namespace blink {
 
 // FIXME: This should not require DeprecatedPaintLayer. There is currently a cycle where
 // in order to determine if we shoulBeNormalFlowOnly() we have to ask the paint
 // layer about some of its state.
@@ skipping 257 matching lines @@
 DeprecatedPaintLayerStackingNode* DeprecatedPaintLayerStackingNode::ancestorStackingContextNode() const
 {
     for (DeprecatedPaintLayer* ancestor = layer()->parent(); ancestor; ancestor = ancestor->parent()) {
         DeprecatedPaintLayerStackingNode* stackingNode = ancestor->stackingNode();
         if (stackingNode->isStackingContext())
             return stackingNode;
     }
     return 0;
 }
 
+static inline LayoutRect frameVisibleRect(LayoutObject* layoutObject)
+{
+    FrameView* frameView = layoutObject->document().view();
+    if (!frameView)
+        return LayoutRect();
+
+    return LayoutRect(frameView->visibleContentRect());
+}
+
 LayoutBoxModelObject* DeprecatedPaintLayerStackingNode::layoutObject() const
 {
     return m_layer->layoutObject();
 }
 
+// I do believe it would be better to have one function here that just returned a vector

[dsinclair, 2015/06/04 18:21:22]

Can you make this a TODO(chadarmstrong) and link to a bug to track this change?

[chadarmstrong, 2015/06/04 18:43:38]

Acknowledged.

+// with the whole tree's stacking contexts in order. This would keep the concept of hit testing
+// and painting abstracted from this class.

[dsinclair, 2015/06/04 18:21:22]

What's stopping us from doing this approach? Is it a lot more work?

[chadarmstrong, 2015/06/04 18:43:38]

Julien believes that allocating an extra array and traversing the tree in two
steps might not be worth the code simplification. I left this comment here to
get other people's thoughts on this as well.

[Julien - ping for review, 2015/06/05 00:46:54]

I strongly believe that this will lead to worse runtime and memory complexity
and unless the code simplification is significant (we discussed this with Chad
and I wasn't convinced in the end), no sane reviewer would accept the change. I
won't hold the change if you see something I missed.

Experimental alternative designs do not belong in a TODO IMHO: we should reserve
TODO for changes we have a high chance of pursuing. They do belong to a
crbug.com bug though.

+bool DeprecatedPaintLayerStackingNode::hitTest(HitTestResult& result)
+{
+    return hitTest(result.hitTestRequest(), result.hitTestLocation(), result);
+}
+
+bool DeprecatedPaintLayerStackingNode::hitTest(const HitTestRequest& request, const HitTestLocation& hitTestLocation, HitTestResult& result)
+{
+    ASSERT(layer()->isSelfPaintingLayer() || layer()->hasSelfPaintingLayerDescendant());
+
+    // LayoutView should make sure to update layout before entering hit testing
+    ASSERT(!layoutObject()->frame()->view()->layoutPending());
+    ASSERT(!layoutObject()->document().layoutView()->needsLayout());
+
+    // Start with frameVisibleRect to ensure we include the scrollbars.
+    LayoutRect hitTestArea = frameVisibleRect(layoutObject());
+    if (request.ignoreClipping())
+        hitTestArea.unite(LayoutRect(layoutObject()->view()->documentRect()));
+
+    DeprecatedPaintLayer* insideLayer = layer()->hitTestLayer(layer(), 0, result, hitTestArea, hitTestLocation, false);
+    if (!insideLayer) {
+        // We didn't hit any layer. If we are the root layer and the mouse is -- or just was -- down,
+        // return ourselves. We do this so mouse events continue getting delivered after a drag has
+        // exited the WebView, and so hit testing over a scrollbar hits the content document.
+        // In addtion, it is possible for the mouse to stay in the document but there is no element.
+        // At that time, the events of the mouse should be fired.
+        LayoutPoint hitPoint = hitTestLocation.point();
+        if (!request.isChildFrameHitTest() && ((request.active() || request.release()) || (request.move() && hitTestArea.contains(hitPoint.x(), hitPoint.y()))) && layer()->isRootLayer()) {
+            layoutObject()->updateHitTestResult(result, toLayoutView(layoutObject())->flipForWritingMode(hitTestLocation.point()));
+            insideLayer = layer();
+        }
+    }
+
+    // Now determine if the result is inside an anchor - if the urlElement isn't already set.
+    Node* node = result.innerNode();
+    if (node && !result.URLElement())
+        result.setURLElement(node->enclosingLinkEventParentOrSelf());
+
+    // Now return whether we were inside this layer (this will always be true for the root
+    // layer).
+    return insideLayer;
+}
+
 } // namespace blink