Bug 1188185 - Zoomed View appears when the two links are the same link. r=kats

layout/base/PositionedEventTargeting.cpp

@@ -34,7 +34,7 @@ namespace mozilla {
  * designing for touch events will take their own steps to account for
  * inaccurate touch events.
  *
- * IsElementClickable() encapsulates the heuristic that determines whether an
+ * GetClickableAncestor() encapsulates the heuristic that determines whether an
  * element is expected to respond to mouse events. An element is deemed
  * "clickable" if it has registered listeners for "click", "mousedown" or
  * "mouseup", or is on a whitelist of element tags (<a>, <button>, <input>,
@@ -48,7 +48,7 @@ namespace mozilla {
  * event radii are disabled), we always use that element. Otherwise we collect
  * all frames intersecting a rectangle around the event position (taking CSS
  * transforms into account) and choose the best candidate in GetClosest().
- * Only IsElementClickable() candidates are considered; if none are found,
+ * Only GetClickableAncestor() candidates are considered; if none are found,
  * then we revert to targeting the element under the event position.
  * We ignore candidates outside the document subtree rooted by the
  * document of the element directly under the event position. This ensures that
@@ -187,8 +187,8 @@ IsDescendant(nsIFrame* aFrame, nsIContent* aAncestor, nsAutoString* aLabelTarget
   return false;
 }
 
-static bool
-IsElementClickable(nsIFrame* aFrame, nsIAtom* stopAt = nullptr, nsAutoString* aLabelTargetId = nullptr)
+static nsIContent*
+GetClickableAncestor(nsIFrame* aFrame, nsIAtom* stopAt = nullptr, nsAutoString* aLabelTargetId = nullptr)
 {
   // Input events propagate up the content tree so we'll follow the content
   // ancestors to look for elements accepting the click.
@@ -198,19 +198,19 @@ IsElementClickable(nsIFrame* aFrame, nsIAtom* stopAt = nullptr, nsAutoString* aL
       break;
     }
     if (HasTouchListener(content) || HasMouseListener(content)) {
-      return true;
+      return content;
     }
     if (content->IsAnyOfHTMLElements(nsGkAtoms::button,
                                      nsGkAtoms::input,
                                      nsGkAtoms::select,
                                      nsGkAtoms::textarea)) {
-      return true;
+      return content;
     }
     if (content->IsHTMLElement(nsGkAtoms::label)) {
       if (aLabelTargetId) {
         content->GetAttr(kNameSpaceID_None, nsGkAtoms::_for, *aLabelTargetId);
       }
-      return true;
+      return content;
     }
 
     // Bug 921928: we don't have access to the content of remote iframe.
@@ -221,7 +221,7 @@ IsElementClickable(nsIFrame* aFrame, nsIAtom* stopAt = nullptr, nsAutoString* aL
                              nsGkAtoms::_true, eIgnoreCase) &&
         content->AttrValueIs(kNameSpaceID_None, nsGkAtoms::Remote,
                              nsGkAtoms::_true, eIgnoreCase)) {
-      return true;
+      return content;
     }
 
     // See nsCSSFrameConstructor::FindXULTagData. This code is not
@@ -236,24 +236,24 @@ IsElementClickable(nsIFrame* aFrame, nsIAtom* stopAt = nullptr, nsAutoString* aL
                                     nsGkAtoms::menulist,
                                     nsGkAtoms::scrollbarbutton,
                                     nsGkAtoms::resizer)) {
-      return true;
+      return content;
     }
 
     static nsIContent::AttrValuesArray clickableRoles[] =
       { &nsGkAtoms::button, &nsGkAtoms::key, nullptr };
     if (content->FindAttrValueIn(kNameSpaceID_None, nsGkAtoms::role,
                                  clickableRoles, eIgnoreCase) >= 0) {
-      return true;
+      return content;
     }
     if (content->IsEditable()) {
-      return true;
+      return content;
     }
     nsCOMPtr<nsIURI> linkURI;
     if (content->IsLink(getter_AddRefs(linkURI))) {
-      return true;
+      return content;
     }
   }
-  return false;
+  return nullptr;
 }
 
 static nscoord
@@ -362,6 +362,7 @@ GetClosest(nsIFrame* aRoot, const nsPoint& aPointRelativeToRootFrame,
            nsIFrame* aRestrictToDescendants, nsIContent* aClickableAncestor,
            nsTArray<nsIFrame*>& aCandidates, int32_t* aElementsInCluster)
 {
+  std::vector<nsIContent*> mContentsInCluster;  // List of content elements in the cluster without duplicate
   nsIFrame* bestTarget = nullptr;
   // Lower is better; distance is in appunits
   float bestDistance = 1e6f;
@@ -375,7 +376,6 @@ GetClosest(nsIFrame* aRoot, const nsPoint& aPointRelativeToRootFrame,
         nsRect(nsPoint(0, 0), f->GetSize()), aRoot, &preservesAxisAlignedRectangles);
     nsRegion region;
     region.And(exposedRegion, borderBox);
-
     if (region.IsEmpty()) {
       PET_LOG("  candidate %p had empty hit region\n", f);
       continue;
@@ -388,12 +388,13 @@ GetClosest(nsIFrame* aRoot, const nsPoint& aPointRelativeToRootFrame,
     }
 
     nsAutoString labelTargetId;
-    if (aClickableAncestor) {
-      if (!IsDescendant(f, aClickableAncestor, &labelTargetId)) {
-        PET_LOG("  candidate %p is not a descendant of required ancestor\n", f);
-        continue;
-      }
-    } else if (!IsElementClickable(f, nsGkAtoms::body, &labelTargetId)) {
+    if (aClickableAncestor && !IsDescendant(f, aClickableAncestor, &labelTargetId)) {
+      PET_LOG("  candidate %p is not a descendant of required ancestor\n", f);
+      continue;
+    }
+
+    nsIContent* clickableContent = GetClickableAncestor(f, nsGkAtoms::body, &labelTargetId);
+    if (!aClickableAncestor && !clickableContent) {
       PET_LOG("  candidate %p was not clickable\n", f);
       continue;
     }
@@ -403,7 +404,7 @@ GetClosest(nsIFrame* aRoot, const nsPoint& aPointRelativeToRootFrame,
       PET_LOG("  candidate %p was ancestor for bestTarget %p\n", f, bestTarget);
       continue;
     }
-    if (!nsLayoutUtils::IsAncestorFrameCrossDoc(aRestrictToDescendants, f, aRoot)) {
+    if (!aClickableAncestor && !nsLayoutUtils::IsAncestorFrameCrossDoc(aRestrictToDescendants, f, aRoot)) {
       PET_LOG("  candidate %p was not descendant of restrictroot %p\n", f, aRestrictToDescendants);
       continue;
     }
@@ -413,7 +414,9 @@ GetClosest(nsIFrame* aRoot, const nsPoint& aPointRelativeToRootFrame,
     // If this element is present in the current list, do not count the frame in
     // the cluster elements counter
     if (labelTargetId.IsEmpty() || !IsElementPresent(aCandidates, labelTargetId)) {
-      (*aElementsInCluster)++;
+      if (std::find(mContentsInCluster.begin(), mContentsInCluster.end(), clickableContent) == mContentsInCluster.end()) {
+        mContentsInCluster.push_back(clickableContent);
+      }
     }
 
     // distance is in appunits
@@ -430,6 +433,7 @@ GetClosest(nsIFrame* aRoot, const nsPoint& aPointRelativeToRootFrame,
       bestTarget = f;
     }
   }
+  *aElementsInCluster = mContentsInCluster.size();
   return bestTarget;
 }
 
@@ -524,12 +528,14 @@ FindFrameTargetedByInputEvent(WidgetGUIEvent* aEvent,
     return target;
   }
   nsIContent* clickableAncestor = nullptr;
-  if (target && IsElementClickable(target, nsGkAtoms::body)) {
-    if (!IsElementClickableAndReadable(target, aEvent, prefs)) {
-      aEvent->AsMouseEventBase()->hitCluster = true;
+  if (target) {
+    clickableAncestor = GetClickableAncestor(target, nsGkAtoms::body);
+    if (clickableAncestor) {
+      if (!IsElementClickableAndReadable(target, aEvent, prefs)) {
+        aEvent->AsMouseEventBase()->hitCluster = true;
+      }
+      PET_LOG("Target %p is clickable\n", target);
     }
-    PET_LOG("Target %p is clickable\n", target);
-    clickableAncestor = target->GetContent();
   }
 
   // Do not modify targeting for actual mouse hardware; only for mouse
@@ -544,7 +550,7 @@ FindFrameTargetedByInputEvent(WidgetGUIEvent* aEvent,
 
   // If the exact target is non-null, only consider candidate targets in the same
   // document as the exact target. Otherwise, if an ancestor document has
-  // a mouse event handler for example, targets that are !IsElementClickable can
+  // a mouse event handler for example, targets that are !GetClickableAncestor can
   // never be targeted --- something nsSubDocumentFrame in an ancestor document
   // would be targeted instead.
   nsIFrame* restrictToDescendants = target ?