Bug 1389848: Make isServiceInstantiated*() return false rather than throw for uninstantiated services. r=ehsan

MozReview-Commit-ID: J8w7eQ6R3eS

--HG--
extra : rebase_source : 5fabd584d645267b72bbcd15bbdfc01dd15f2386

browser/components/tests/startupRecorder.js

@@ -46,8 +46,7 @@ startupRecorder.prototype = {
       modules: this.loader.loadedModules(),
       services: Object.keys(Cc).filter(c => {
         try {
-          Cm.isServiceInstantiatedByContractID(c, Ci.nsISupports);
-          return true;
+          return Cm.isServiceInstantiatedByContractID(c, Ci.nsISupports);
         } catch (e) {
           return false;
         }

xpcom/components/nsComponentManager.cpp

@@ -1316,7 +1316,7 @@ nsComponentManagerImpl::IsServiceInstantiated(const nsCID& aClass,
     return NS_ERROR_UNEXPECTED;
   }
 
-  nsresult rv = NS_ERROR_SERVICE_NOT_AVAILABLE;
+  nsresult rv = NS_OK;
   nsFactoryEntry* entry;
 
   {
@@ -1328,6 +1328,8 @@ nsComponentManagerImpl::IsServiceInstantiated(const nsCID& aClass,
     nsCOMPtr<nsISupports> service;
     rv = entry->mServiceObject->QueryInterface(aIID, getter_AddRefs(service));
     *aResult = (service != nullptr);
+  } else {
+    *aResult = false;
   }
 
   return rv;
@@ -1356,7 +1358,7 @@ nsComponentManagerImpl::IsServiceInstantiatedByContractID(
     return NS_ERROR_UNEXPECTED;
   }
 
-  nsresult rv = NS_ERROR_SERVICE_NOT_AVAILABLE;
+  nsresult rv = NS_OK;
   nsFactoryEntry* entry;
   {
     SafeMutexAutoLock lock(mLock);
@@ -1367,6 +1369,8 @@ nsComponentManagerImpl::IsServiceInstantiatedByContractID(
     nsCOMPtr<nsISupports> service;
     rv = entry->mServiceObject->QueryInterface(aIID, getter_AddRefs(service));
     *aResult = (service != nullptr);
+  } else {
+    *aResult = false;
   }
   return rv;
 }

xpcom/components/nsIServiceManager.idl

@@ -45,13 +45,12 @@ interface nsIServiceManager : nsISupports
      * isServiceInstantiated
      *
      * isServiceInstantiated will return a true if the service has already
-     * been created, or throw otherwise
+     * been created, or false otherwise. Throws if the service does not
+     * implement the given IID.
      *
      * @param aClass or aContractID : aClass or aContractID of object 
      *                                instance requested
      * @param aIID : IID of interface requested
-     * @throws NS_ERROR_SERVICE_NOT_AVAILABLE if the service hasn't been 
-     *         instantiated
      * @throws NS_NOINTERFACE if the IID given isn't supported by the object
      */
     boolean isServiceInstantiated(in nsCIDRef aClass, in nsIIDRef aIID);