Implement elementsFromPoint

Source/core/page/EventHandler.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2012 Digia Plc. and/or its subsidiary(-ies)
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
@@ skipping 871 matching lines @@
 
     // RenderView::hitTest causes a layout, and we don't want to hit that until the first
     // layout because until then, there is nothing shown on the screen - the user can't
     // have intentionally clicked on something belonging to this page. Furthermore,
     // mousemove events before the first layout should not lead to a premature layout()
     // happening, which could show a flash of white.
     // See also the similar code in Document::prepareMouseEvent.
     if (!m_frame->contentRenderer() || !m_frame->view() || !m_frame->view()->didFirstLayout())
         return result;
 
+    if (padding.width() || padding.height())
+        hitType |= HitTestRequest::ListBased;

[Rick Byers, 2015/02/04 10:34:03]

Perhaps we should require callers to opt-in to list-based explicitly and enforce
it with ASSERTs?  It's kind of subtle that you get list behavior by providing a
width/height (I was certainly confused by that originally).  I don't think there
are many places to update (mainly EventHandler::hitTestResultForGestureEvent,
the TouchDisambiguation case you already updated, and possibly the testing path
via Internals.cpp).

[pdr., 2015/02/17 04:10:13]

Added back! I took this out thinking it would be easier to review, but that was
dumb of me.

+
     // hitTestResultAtPoint is specifically used to hitTest into all frames, thus it always allows child frame content.
     HitTestRequest request(hitType | HitTestRequest::AllowChildFrameContent);
     m_frame->contentRenderer()->hitTest(request, result);
     if (!request.readOnly())
         m_frame->document()->updateHoverActiveState(request, result.innerElement());
 
     return result;
 }
 
 void EventHandler::stopAutoscroll()
@@ skipping 1691 matching lines @@
     // scrollbars being untouchable.
     if (result.scrollbar()) {
         targetNode = 0;
         return false;
     }
 
     IntPoint touchCenter = m_frame->view()->contentsToWindow(result.roundedPointInMainFrame());
     IntRect touchRect = m_frame->view()->contentsToWindow(result.hitTestLocation().boundingBox());
 
     WillBeHeapVector<RefPtrWillBeMember<Node>, 11> nodes;
-    copyToVector(result.rectBasedTestResult(), nodes);
+    copyToVector(result.listBasedTestResult(), nodes);
 
     // FIXME: the explicit Vector conversion copies into a temporary and is wasteful.
     return findBestClickableCandidate(targetNode, targetPoint, touchCenter, touchRect, WillBeHeapVector<RefPtrWillBeMember<Node>> (nodes));
 }
 
 bool EventHandler::bestContextMenuNodeForHitTestResult(const HitTestResult& result, IntPoint& targetPoint, Node*& targetNode)
 {
     ASSERT(result.isRectBasedTest());
     IntPoint touchCenter = m_frame->view()->contentsToWindow(result.roundedPointInMainFrame());
     IntRect touchRect = m_frame->view()->contentsToWindow(result.hitTestLocation().boundingBox());
     WillBeHeapVector<RefPtrWillBeMember<Node>, 11> nodes;
-    copyToVector(result.rectBasedTestResult(), nodes);
+    copyToVector(result.listBasedTestResult(), nodes);
 
     // FIXME: the explicit Vector conversion copies into a temporary and is wasteful.
     return findBestContextMenuCandidate(targetNode, targetPoint, touchCenter, touchRect, WillBeHeapVector<RefPtrWillBeMember<Node>>(nodes));
 }
 
 bool EventHandler::bestZoomableAreaForTouchPoint(const IntPoint& touchCenter, const IntSize& touchRadius, IntRect& targetArea, Node*& targetNode)
 {
     IntPoint hitTestPoint = m_frame->view()->windowToContents(touchCenter);
     HitTestResult result = hitTestResultAtPoint(hitTestPoint, HitTestRequest::ReadOnly | HitTestRequest::Active, LayoutSize(touchRadius));
 
     IntRect touchRect(touchCenter - touchRadius, touchRadius + touchRadius);
     WillBeHeapVector<RefPtrWillBeMember<Node>, 11> nodes;
-    copyToVector(result.rectBasedTestResult(), nodes);
+    copyToVector(result.listBasedTestResult(), nodes);
 
     // FIXME: the explicit Vector conversion copies into a temporary and is wasteful.
     return findBestZoomableArea(targetNode, targetArea, touchCenter, touchRect, WillBeHeapVector<RefPtrWillBeMember<Node>>(nodes));
 }
 
 GestureEventWithHitTestResults EventHandler::targetGestureEvent(const PlatformGestureEvent& gestureEvent, bool readOnly)
 {
     TRACE_EVENT0("input", "EventHandler::targetGestureEvent");
 
     ASSERT(m_frame == m_frame->localFrameRoot());
@@ skipping 50 matching lines @@
     applyTouchAdjustment(&adjustedEvent, &hitTestResult);
 
     // Do a new hit-test at the (adjusted) gesture co-ordinates. This is necessary because
     // rect-based hit testing and touch adjustment sometimes return a different node than
     // what a point-based hit test would return for the same point.
     // FIXME: Fix touch adjustment to avoid the need for a redundant hit test. http://crbug.com/398914
     if (shouldApplyTouchAdjustment(gestureEvent)) {
         LocalFrame* hitFrame = hitTestResult.innerNodeFrame();
         if (!hitFrame)
             hitFrame = m_frame;
-        hitTestResult = hitTestResultInFrame(hitFrame, hitFrame->view()->windowToContents(adjustedEvent.position()), hitType | HitTestRequest::ReadOnly);
+        hitTestResult = hitTestResultInFrame(hitFrame, hitFrame->view()->windowToContents(adjustedEvent.position()), (hitType | HitTestRequest::ReadOnly) & ~HitTestRequest::ListBased);
     }
 
     // If we did a rect-based hit test it must be resolved to the best single node by now to
     // ensure consumers don't accidentally use one of the other candidates.
     ASSERT(!hitTestResult.isRectBasedTest());
 
     return GestureEventWithHitTestResults(adjustedEvent, hitTestResult);
 }
 
 HitTestRequest::HitTestRequestType EventHandler::getHitTypeForGestureType(PlatformEvent::Type type)
@@ skipping 1196 matching lines @@
 unsigned EventHandler::accessKeyModifiers()
 {
 #if OS(MACOSX)
     return PlatformEvent::CtrlKey | PlatformEvent::AltKey;
 #else
     return PlatformEvent::AltKey;
 #endif
 }
 
 } // namespace blink