Bug 1212360. Split up the MozStorageChanged event into separate events for sessionstorage and localstorage. r=khuey

browser/components/sessionstore/content/content-sessionStore.js

@@ -61,20 +61,6 @@ function createLazy(fn) {
   };
 }
 
-/**
- * Determines whether the given storage event was triggered by changes
- * to the sessionStorage object and not the local or globalStorage.
- */
-function isSessionStorageEvent(event) {
-  try {
-    return event.storageArea == event.target.sessionStorage;
-  } catch (ex if ex instanceof Ci.nsIException && ex.result == Cr.NS_ERROR_NOT_AVAILABLE) {
-    // This page does not have a DOMSessionStorage
-    // (this is typically the case for about: pages)
-    return false;
-  }
-}
-
 /**
  * Listens for and handles content events that we need for the
  * session store service to be notified of state changes in content.
@@ -520,7 +506,7 @@ var DocShellCapabilitiesListener = {
  */
 var SessionStorageListener = {
   init: function () {
-    addEventListener("MozStorageChanged", this, true);
+    addEventListener("MozSessionStorageChanged", this, true);
     Services.obs.addObserver(this, "browser:purge-domain-data", false);
     gFrameTree.addObserver(this);
   },
@@ -530,8 +516,7 @@ var SessionStorageListener = {
   },
 
   handleEvent: function (event) {
-    // Ignore events triggered by localStorage or globalStorage changes.
-    if (gFrameTree.contains(event.target) && isSessionStorageEvent(event)) {
+    if (gFrameTree.contains(event.target)) {
       this.collect();
     }
   },

browser/components/sessionstore/test/head.js

@@ -550,13 +550,13 @@ function modifySessionStorage(browser, data, options = {}) {
     let storage = frame.sessionStorage;
 
     return new Promise(resolve => {
-      addEventListener("MozStorageChanged", function onStorageChanged(event) {
+      addEventListener("MozSessionStorageChanged", function onStorageChanged(event) {
         if (event.storageArea == storage) {
           keys.delete(event.key);
         }
 
         if (keys.size == 0) {
-          removeEventListener("MozStorageChanged", onStorageChanged, true);
+          removeEventListener("MozSessionStorageChanged", onStorageChanged, true);
           resolve();
         }
       }, true);

dom/base/nsGlobalWindow.cpp

@@ -11837,6 +11837,8 @@ nsGlobalWindow::Observe(nsISupports* aSubject, const char* aTopic,
     nsCOMPtr<nsIDOMStorage> istorage = changingStorage.get();
 
     bool fireMozStorageChanged = false;
+    nsAutoString eventType;
+    eventType.AssignLiteral("storage");
     principal = GetPrincipal();
     if (!principal) {
       return NS_OK;
@@ -11872,6 +11874,9 @@ nsGlobalWindow::Observe(nsISupports* aSubject, const char* aTopic,
       }
 
       fireMozStorageChanged = mSessionStorage == changingStorage;
+      if (fireMozStorageChanged) {
+        eventType.AssignLiteral("MozSessionStorageChanged");
+      }
       break;
     }
 
@@ -11889,6 +11894,9 @@ nsGlobalWindow::Observe(nsISupports* aSubject, const char* aTopic,
         return NS_OK;
 
       fireMozStorageChanged = mLocalStorage == changingStorage;
+      if (fireMozStorageChanged) {
+        eventType.AssignLiteral("MozLocalStorageChanged");
+      };
       break;
     }
     default:
@@ -11898,11 +11906,8 @@ nsGlobalWindow::Observe(nsISupports* aSubject, const char* aTopic,
     // Clone the storage event included in the observer notification. We want
     // to dispatch clones rather than the original event.
     ErrorResult error;
-    nsRefPtr<StorageEvent> newEvent =
-      CloneStorageEvent(fireMozStorageChanged ?
-                          NS_LITERAL_STRING("MozStorageChanged") :
-                          NS_LITERAL_STRING("storage"),
-                        event, error);
+    nsRefPtr<StorageEvent> newEvent = CloneStorageEvent(eventType,
+                                                        event, error);
     if (error.Failed()) {
       return error.StealNSResult();
     }

dom/tests/mochitest/localstorage/test_localStorageBase.html

@@ -62,8 +62,8 @@ function startTest()
     }
   }
 
-  // Listen for MozStorageChanged
-  SpecialPowers.addChromeEventListener("MozStorageChanged", onStorageChanged, false);
+  // Listen for MozLocalStorageChanged
+  SpecialPowers.addChromeEventListener("MozLocalStorageChanged", onStorageChanged, false);
 
   // add an empty-value key
   localStorage.setItem("empty", "");
@@ -227,7 +227,7 @@ function startTest()
   localStorage.removeItem("key2"); // Just check there is no exception
 
   SimpleTest.executeSoon(function () {
-    SpecialPowers.removeChromeEventListener("MozStorageChanged", onStorageChanged, false);
+    SpecialPowers.removeChromeEventListener("MozLocalStorageChanged", onStorageChanged, false);
     is(expectedEvents.length, 0, "received the correct number of events");
 
     localStorage.clear();

dom/tests/mochitest/sessionstorage/test_sessionStorageBase.html

@@ -44,7 +44,6 @@ function startTest()
   is(typeof sessionStorage["nonexisting2"], "undefined", "['nonexisting2'] is undefined");
   is(typeof sessionStorage.nonexisting2, "undefined", "nonexisting2 is undefined");
 
-  var mozStorageChangedReceived = 0;
   var sessionStorageCopy = sessionStorage;
 
   function onStorageChanged(e) {
@@ -55,8 +54,8 @@ function startTest()
     }
   }
 
-  // Listen for MozStorageChanged
-  SpecialPowers.addChromeEventListener("MozStorageChanged", onStorageChanged, false);
+  // Listen for MozSessionStorageChanged
+  SpecialPowers.addChromeEventListener("MozSessionStorageChanged", onStorageChanged, false);
 
   // add an empty-value key
   sessionStorage.setItem("empty", "");
@@ -161,7 +160,7 @@ function startTest()
   sessionStorage.removeItem("key2"); // Just check there is no exception
 
   SimpleTest.executeSoon(function () {
-    SpecialPowers.removeChromeEventListener("MozStorageChanged", onStorageChanged, false);
+    SpecialPowers.removeChromeEventListener("MozSessionStorageChanged", onStorageChanged, false);
     is(expectedEvents.length, 0, "received the correct number of events");
 
     sessionStorage.clear();