Bug 616090 - Optimize timer in nsDOMStorageDBWrapper. r=honzab a=blocking-fennec

dom/src/storage/nsDOMStorage.cpp

@@ -441,6 +441,8 @@ nsDOMStorageManager::Observe(nsISupports *aSubject,
     nsCOMPtr<nsIObserverService> obsserv = mozilla::services::GetObserverService();
     if (obsserv)
       obsserv->NotifyObservers(nsnull, NS_DOMSTORAGE_FLUSH_TIMER_OBSERVER, nsnull);
+    if (!UnflushedDataExists())
+      DOMStorageImpl::gStorageDB->StopTempTableFlushTimer();
   } else if (!strcmp(aTopic, "browser:purge-domain-data")) {
     // Convert the domain name to the ACE format
     nsCAutoString aceDomain;
@@ -537,6 +539,26 @@ nsDOMStorageManager::RemoveFromStoragesHash(DOMStorageImpl* aStorage)
     mStorages.RemoveEntry(aStorage);
 }
 
+static PLDHashOperator
+CheckUnflushedData(nsDOMStorageEntry* aEntry, void* userArg)
+{
+  if (aEntry->mStorage->WasTemporaryTableLoaded()) {
+    PRBool *unflushedData = (PRBool*)userArg;
+    *unflushedData = PR_TRUE;
+    return PL_DHASH_STOP;
+  }
+
+  return PL_DHASH_NEXT;
+}
+
+PRBool
+nsDOMStorageManager::UnflushedDataExists()
+{
+  PRBool unflushedData = PR_FALSE;
+  mStorages.EnumerateEntries(CheckUnflushedData, &unflushedData);
+  return unflushedData;
+}
+
 //
 // nsDOMStorage
 //
@@ -1055,6 +1077,8 @@ DOMStorageImpl::SetTemporaryTableLoaded(bool loaded)
     mLastTemporaryTableAccessTime = TimeStamp::Now();
     if (!mLoadedTemporaryTable)
       mTemporaryTableAge = mLastTemporaryTableAccessTime;
+
+    gStorageDB->EnsureTempTableFlushTimer();
   }
 
   mLoadedTemporaryTable = loaded;

dom/src/storage/nsDOMStorage.h

@@ -136,6 +136,11 @@ public:
   static nsDOMStorageManager* GetInstance();
   static void Shutdown();
 
+  /**
+   * Checks whether there is any data waiting to be flushed from a temp table.
+   */
+  PRBool UnflushedDataExists();
+
   static nsDOMStorageManager* gStorageManager;
 
 protected:

dom/src/storage/nsDOMStorageDBWrapper.cpp

@@ -75,9 +75,7 @@ nsDOMStorageDBWrapper::nsDOMStorageDBWrapper()
 
 nsDOMStorageDBWrapper::~nsDOMStorageDBWrapper()
 {
-  if (mFlushTimer) {
-    mFlushTimer->Cancel();
-  }
+  StopTempTableFlushTimer();
 }
 
 nsresult
@@ -97,13 +95,6 @@ nsDOMStorageDBWrapper::Init()
   rv = mPrivateBrowsingDB.Init();
   NS_ENSURE_SUCCESS(rv, rv);
 
-  mFlushTimer = do_CreateInstance(NS_TIMER_CONTRACTID, &rv);
-  NS_ENSURE_SUCCESS(rv, rv);
-
-  rv = mFlushTimer->Init(nsDOMStorageManager::gStorageManager, 5000,
-                         nsITimer::TYPE_REPEATING_SLACK);
-  NS_ENSURE_SUCCESS(rv, rv);
-
   return NS_OK;
 }
 
@@ -452,3 +443,30 @@ nsDOMStorageDBWrapper::GetDomainFromScopeKey(const nsACString& aScope,
   ReverseString(reverseDomain, aDomain);
   return NS_OK;
 }
+
+void
+nsDOMStorageDBWrapper::EnsureTempTableFlushTimer()
+{
+  if (!mTempTableFlushTimer) {
+    nsresult rv;
+    mTempTableFlushTimer = do_CreateInstance(NS_TIMER_CONTRACTID, &rv);
+
+    if (!NS_SUCCEEDED(rv)) {
+      mTempTableFlushTimer = nsnull;
+      return;
+    }
+
+    mTempTableFlushTimer->Init(nsDOMStorageManager::gStorageManager, 5000,
+                               nsITimer::TYPE_REPEATING_SLACK);
+  }
+}
+
+void
+nsDOMStorageDBWrapper::StopTempTableFlushTimer()
+{
+  if (mTempTableFlushTimer) {
+    mTempTableFlushTimer->Cancel();
+    mTempTableFlushTimer = nsnull;
+  }
+}
+

dom/src/storage/nsDOMStorageDBWrapper.h

@@ -221,13 +221,24 @@ public:
   static nsresult GetDomainFromScopeKey(const nsACString& aScope,
                                          nsACString& aDomain);
 
+  /**
+   * Ensures the temp table flush timer is running. This is called when we add
+   * data that will need to be flushed.
+   */
+  void EnsureTempTableFlushTimer();
+
+  /**
+   * Stops the temp table flush timer.
+   */
+  void StopTempTableFlushTimer();
+
 protected:
   nsDOMStoragePersistentDB mChromePersistentDB;
   nsDOMStoragePersistentDB mPersistentDB;
   nsDOMStorageMemoryDB mSessionOnlyDB;
   nsDOMStorageMemoryDB mPrivateBrowsingDB;
 
-  nsCOMPtr<nsITimer> mFlushTimer;
+  nsCOMPtr<nsITimer> mTempTableFlushTimer;
 };
 
 #endif /* nsDOMStorageDB_h___ */