Bug 651984 - Add ability to detect if a page has registered touch event listeners, r=jst

content/base/src/nsNodeUtils.cpp

@@ -558,6 +558,9 @@ nsNodeUtils::CloneAndAdopt(nsINode *aNode, PRBool aClone, PRBool aDeep,
             window->SetHasAudioAvailableEventListeners();
           }
 #endif
+          if (elm->MayHaveTouchEventListener()) {
+            window->SetHasTouchEventListeners();
+          }
         }
       }
     }

content/events/public/nsIEventListenerManager.h

@@ -56,8 +56,8 @@ class nsCxPusher;
  * Event listener manager interface.
  */
 #define NS_IEVENTLISTENERMANAGER_IID \
-{ 0xe86a148b, 0x0563, 0x454f, \
+{ 0x8e8667ed, 0x10d3, 0x41e8, \
-  { 0x8c, 0xf2, 0xbd, 0xc4, 0x7c, 0xe6, 0xbe, 0x91 } }
+  { 0x93, 0xfa, 0xa4, 0xc4, 0xea, 0x16, 0x85, 0xd5 } }
 
 class nsIEventListenerManager : public nsISupports {
 
@@ -69,6 +69,7 @@ public:
     mMayHaveCapturingListeners(PR_FALSE),
     mMayHaveSystemGroupListeners(PR_FALSE),
     mMayHaveAudioAvailableEventListener(PR_FALSE),
+    mMayHaveTouchEventListener(PR_FALSE),
     mNoListenerForEvent(0)
   {}
 
@@ -212,14 +213,19 @@ public:
    */
   PRBool MayHaveAudioAvailableEventListener() { return mMayHaveAudioAvailableEventListener; }
 
-
+  /**
+   * Returns PR_TRUE if there may be a touch event listener registered,
+   * PR_FALSE if there definitely isn't.
+   */
+  PRBool MayHaveTouchEventListener() { return mMayHaveTouchEventListener; }
 protected:
   PRUint32 mMayHavePaintEventListener : 1;
   PRUint32 mMayHaveMutationListeners : 1;
   PRUint32 mMayHaveCapturingListeners : 1;
   PRUint32 mMayHaveSystemGroupListeners : 1;
   PRUint32 mMayHaveAudioAvailableEventListener : 1;
-  PRUint32 mNoListenerForEvent : 27;
+  PRUint32 mMayHaveTouchEventListener : 1;
+  PRUint32 mNoListenerForEvent : 26;
 };
 
 NS_DEFINE_STATIC_IID_ACCESSOR(nsIEventListenerManager,

content/events/src/nsEventListenerManager.cpp

@@ -507,7 +507,14 @@ nsEventListenerManager::AddEventListener(nsIDOMEventListener *aListener,
     nsPIDOMWindow* window = GetInnerWindowForTarget();
     if (window)
       window->SetHasOrientationEventListener();
-  } else if (aType >= NS_MOZTOUCH_DOWN && aType <= NS_MOZTOUCH_UP) {
+  } else if ((aType >= NS_MOZTOUCH_DOWN && aType <= NS_MOZTOUCH_UP) ||
+             (aTypeAtom == nsGkAtoms::ontouchstart ||
+              aTypeAtom == nsGkAtoms::ontouchend ||
+              aTypeAtom == nsGkAtoms::ontouchmove ||
+              aTypeAtom == nsGkAtoms::ontouchenter ||
+              aTypeAtom == nsGkAtoms::ontouchleave ||
+              aTypeAtom == nsGkAtoms::ontouchcancel)) {
+    mMayHaveTouchEventListener = PR_TRUE;
     nsPIDOMWindow* window = GetInnerWindowForTarget();
     if (window)
       window->SetHasTouchEventListeners();

content/events/test/test_bug648573.html

@@ -20,6 +20,9 @@ https://bugzilla.mozilla.org/show_bug.cgi?id=648573
 
 /** Test for Bug 648573 **/
 
+ok(!SpecialPowers.DOMWindowUtils.mayHaveTouchEventListeners,
+  "There shouldn't be any touch event listeners yet.");
+
 ok("createTouch" in document, "Should have createTouch function");
 ok("createTouchList" in document, "Should have createTouchList function");
 ok(document.createEvent("touchevent"), "Should be able to create TouchEvent objects");
@@ -98,6 +101,9 @@ function runEventTest(type) {
 for (var i = 0; i < events.length; ++i) {
   runEventTest(events[i]);
 }
+
+ok(SpecialPowers.DOMWindowUtils.mayHaveTouchEventListeners,
+  "There should be touch event listeners.");
 </script>
 </pre>
 </body>

dom/base/nsDOMWindowUtils.cpp

@@ -1861,3 +1861,16 @@ nsDOMWindowUtils::LeafLayersPartitionWindow(PRBool* aResult)
 #endif
   return NS_OK;
 }
+
+NS_IMETHODIMP
+nsDOMWindowUtils::GetMayHaveTouchEventListeners(PRBool* aResult)
+{
+  if (!IsUniversalXPConnectCapable()) {
+    return NS_ERROR_DOM_SECURITY_ERR;
+  }
+
+  nsPIDOMWindow* innerWindow = mWindow->GetCurrentInnerWindow();
+  *aResult = innerWindow ? innerWindow->HasTouchEventListeners() : PR_FALSE;
+  return NS_OK;
+}
+

dom/base/nsPIDOMWindow.h

@@ -78,8 +78,8 @@ class nsIArray;
 class nsPIWindowRoot;
 
 #define NS_PIDOMWINDOW_IID \
-{ 0x8d8be7db, 0xffaa, 0x4962, \
+{ 0xafc4849b, 0x21d3, 0x45ea, \
-  { 0xa7, 0x27, 0xb7, 0x0f, 0xc9, 0xfa, 0xd3, 0x0e } }
+  { 0x8b, 0xfd, 0x61, 0xec, 0x12, 0x5d, 0x38, 0x64 } }
 
 class nsPIDOMWindow : public nsIDOMWindowInternal
 {
@@ -442,6 +442,11 @@ public:
     MaybeUpdateTouchState();
   }
 
+  PRBool HasTouchEventListeners()
+  {
+    return mMayHaveTouchEventListener;
+  }
+
   /**
    * Call this to check whether some node (this window, its document,
    * or content in that document) has a MozAudioAvailable event listener.

dom/interfaces/base/nsIDOMWindowUtils.idl

@@ -66,7 +66,7 @@ interface nsITransferable;
 interface nsIQueryContentEventResult;
 interface nsIDOMWindow;
 
-[scriptable, uuid(3828e648-af61-47e1-b9bc-89ca51bc19f2)]
+[scriptable, uuid(663e33d7-eca2-42e8-af92-5df6a5e222df)]
 interface nsIDOMWindowUtils : nsISupports {
 
   /**
@@ -881,4 +881,9 @@ interface nsIDOMWindowUtils : nsISupports {
    * the bounds of the window. Always returns true in non-DEBUG builds.
    */
   boolean leafLayersPartitionWindow();
+
+  /**
+   * true if the (current inner) window may have event listeners for touch events.
+   */
+  readonly attribute boolean mayHaveTouchEventListeners;
 };