Bug 584319 - 'IndexedDB: Out of Memory error and crash when calling moz_indexedDB.open a lot'. r=sicking

dom/indexedDB/AsyncConnectionHelper.cpp

@@ -172,12 +172,6 @@ AsyncConnectionHelper::Run()
       NS_ASSERTION(connection, "This should never be null!");
     }
   }
-  else if (mDatabase) {
-    rv = mDatabase->GetOrCreateConnection(getter_AddRefs(connection));
-    if (NS_SUCCEEDED(rv)) {
-      NS_ASSERTION(connection, "This should never be null!");
-    }
-  }
 
   if (connection) {
     rv = connection->SetProgressHandler(kProgressHandlerGranularity, this,

dom/indexedDB/CheckPermissionsHelper.cpp

@@ -147,14 +147,14 @@ CheckPermissionsHelper::Run()
   nsRefPtr<AsyncConnectionHelper> helper;
   helper.swap(mHelper);
 
-  nsCOMPtr<nsIThread> thread;
-  thread.swap(mThread);
-
   nsCOMPtr<nsIDOMWindow> window;
   window.swap(mWindow);
 
   if (permission == nsIPermissionManager::ALLOW_ACTION) {
-    return helper->Dispatch(thread);
+    IndexedDatabaseManager* mgr = IndexedDatabaseManager::Get();
+    NS_ASSERTION(mgr, "This should never be null!");
+
+    return helper->Dispatch(mgr->IOThread());
   }
 
   NS_ASSERTION(permission == nsIPermissionManager::UNKNOWN_ACTION ||

dom/indexedDB/CheckPermissionsHelper.h

@@ -63,25 +63,21 @@ public:
   NS_DECL_NSIOBSERVER
 
   CheckPermissionsHelper(AsyncConnectionHelper* aHelper,
-                         nsIThread* aThread,
                          nsIDOMWindow* aWindow,
                          const nsACString& aASCIIOrigin)
   : mHelper(aHelper),
-    mThread(aThread),
     mWindow(aWindow),
     mASCIIOrigin(aASCIIOrigin),
     mHasPrompted(PR_FALSE),
     mPromptResult(0)
   {
     NS_ASSERTION(aHelper, "Null pointer!");
-    NS_ASSERTION(aThread, "Null pointer!");
     NS_ASSERTION(aWindow, "Null pointer!");
     NS_ASSERTION(!aASCIIOrigin.IsEmpty(), "Empty host!");
   }
 
 private:
   nsRefPtr<AsyncConnectionHelper> mHelper;
-  nsCOMPtr<nsIThread> mThread;
   nsCOMPtr<nsIDOMWindow> mWindow;
   nsCString mASCIIOrigin;
   PRBool mHasPrompted;

dom/indexedDB/DatabaseInfo.cpp

@@ -81,6 +81,54 @@ EnumerateObjectStoreNames(const nsAString& aKey,
 
 }
 
+#ifdef NS_BUILD_REFCNT_LOGGING
+DatabaseInfo::DatabaseInfo()
+: id(0)
+{
+  MOZ_COUNT_CTOR(DatabaseInfo);
+}
+
+DatabaseInfo::~DatabaseInfo()
+{
+  MOZ_COUNT_DTOR(DatabaseInfo);
+}
+
+IndexInfo::IndexInfo()
+: id(LL_MININT),
+  unique(false),
+  autoIncrement(false)
+{
+  MOZ_COUNT_CTOR(IndexInfo);
+}
+
+IndexInfo::~IndexInfo()
+{
+  MOZ_COUNT_DTOR(IndexInfo);
+}
+
+ObjectStoreInfo::ObjectStoreInfo()
+: id(0),
+  autoIncrement(false),
+  databaseId(0)
+{
+  MOZ_COUNT_CTOR(ObjectStoreInfo);
+}
+
+ObjectStoreInfo::~ObjectStoreInfo()
+{
+  MOZ_COUNT_DTOR(ObjectStoreInfo);
+}
+
+IndexUpdateInfo::IndexUpdateInfo()
+{
+  MOZ_COUNT_CTOR(IndexUpdateInfo);
+}
+IndexUpdateInfo::~IndexUpdateInfo()
+{
+  MOZ_COUNT_DTOR(IndexUpdateInfo);
+}
+#endif /* NS_BUILD_REFCNT_LOGGING */
+
 // static
 bool
 DatabaseInfo::Get(PRUint32 aId,

dom/indexedDB/DatabaseInfo.h

@@ -57,8 +57,13 @@ struct DatabaseInfo
 
   nsAutoRefCnt referenceCount;
 
+#ifdef NS_BUILD_REFCNT_LOGGING
+  DatabaseInfo();
+  ~DatabaseInfo();
+#else
   DatabaseInfo()
   : id(0) { }
+#endif
 
   static bool Get(PRUint32 aId,
                   DatabaseInfo** aInfo);
@@ -73,8 +78,13 @@ struct DatabaseInfo
 
 struct IndexInfo
 {
+#ifdef NS_BUILD_REFCNT_LOGGING
+  IndexInfo();
+  ~IndexInfo();
+#else
   IndexInfo()
   : id(LL_MININT), unique(false), autoIncrement(false) { }
+#endif
 
   PRInt64 id;
   nsString name;
@@ -92,8 +102,13 @@ struct ObjectStoreInfo
   PRUint32 databaseId;
   nsTArray<IndexInfo> indexes;
 
+#ifdef NS_BUILD_REFCNT_LOGGING
+  ObjectStoreInfo();
+  ~ObjectStoreInfo();
+#else
   ObjectStoreInfo()
   : id(0), autoIncrement(false), databaseId(0) { }
+#endif
 
   static bool Get(PRUint32 aDatabaseId,
                   const nsAString& aName,
@@ -107,6 +122,11 @@ struct ObjectStoreInfo
 
 struct IndexUpdateInfo
 {
+#ifdef NS_BUILD_REFCNT_LOGGING
+  IndexUpdateInfo();
+  ~IndexUpdateInfo();
+#endif
+
   IndexInfo info;
   Key value;
 };

dom/indexedDB/IDBDatabase.cpp

@@ -224,14 +224,10 @@ already_AddRefed<IDBDatabase>
 IDBDatabase::Create(nsIScriptContext* aScriptContext,
                     nsPIDOMWindow* aOwner,
                     DatabaseInfo* aDatabaseInfo,
-                    LazyIdleThread* aThread,
-                    nsCOMPtr<mozIStorageConnection>& aConnection,
                     const nsACString& aASCIIOrigin)
 {
   NS_ASSERTION(NS_IsMainThread(), "Wrong thread!");
   NS_ASSERTION(aDatabaseInfo, "Null pointer!");
-  NS_ASSERTION(aThread, "Null pointer!");
-  NS_ASSERTION(aConnection, "Null pointer!");
   NS_ASSERTION(!aASCIIOrigin.IsEmpty(), "Empty origin!");
 
   nsRefPtr<IDBDatabase> db(new IDBDatabase());
@@ -245,16 +241,11 @@ IDBDatabase::Create(nsIScriptContext* aScriptContext,
   db->mFilePath = aDatabaseInfo->filePath;
   db->mASCIIOrigin = aASCIIOrigin;
 
-  aThread->SetWeakIdleObserver(db);
-  db->mConnectionThread = aThread;
-
-  db->mConnection.swap(aConnection);
-
   IndexedDatabaseManager* mgr = IndexedDatabaseManager::Get();
   NS_ASSERTION(mgr, "This should never be null!");
 
   if (!mgr->RegisterDatabase(db)) {
-    NS_WARNING("Out of memory?");
+    // Either out of memory or shutting down.
     return nsnull;
   }
 
@@ -263,7 +254,8 @@ IDBDatabase::Create(nsIScriptContext* aScriptContext,
 
 IDBDatabase::IDBDatabase()
 : mDatabaseId(0),
-  mInvalidated(0)
+  mInvalidated(0),
+  mRegistered(false)
 {
   NS_ASSERTION(NS_IsMainThread(), "Wrong thread!");
 
@@ -276,17 +268,14 @@ IDBDatabase::IDBDatabase()
 IDBDatabase::~IDBDatabase()
 {
   NS_ASSERTION(NS_IsMainThread(), "Wrong thread!");
-  IndexedDatabaseManager* mgr = IndexedDatabaseManager::Get();
-  if (mgr) {
-    mgr->UnregisterDatabase(this);
-  }
 
-  if (mConnectionThread) {
+  if (mRegistered) {
-    mConnectionThread->SetWeakIdleObserver(nsnull);
+    IndexedDatabaseManager* mgr = IndexedDatabaseManager::Get();
+    if (mgr) {
+      mgr->UnregisterDatabase(this);
+    }
   }
 
-  CloseConnection();
-
   if (mDatabaseId && !mInvalidated) {
     DatabaseInfo* info;
     if (!DatabaseInfo::Get(mDatabaseId, &info)) {
@@ -314,40 +303,6 @@ IDBDatabase::~IDBDatabase()
   }
 }
 
-nsresult
-IDBDatabase::GetOrCreateConnection(mozIStorageConnection** aResult)
-{
-  NS_ASSERTION(!NS_IsMainThread(), "Wrong thread!");
-
-  if (mInvalidated) {
-    return NS_ERROR_NOT_AVAILABLE;
-  }
-
-  if (!mConnection) {
-    mConnection = IDBFactory::GetConnection(mFilePath);
-    NS_ENSURE_TRUE(mConnection, NS_ERROR_FAILURE);
-  }
-
-  nsCOMPtr<mozIStorageConnection> result(mConnection);
-  result.forget(aResult);
-  return NS_OK;
-}
-
-void
-IDBDatabase::CloseConnection()
-{
-  if (mConnection) {
-    if (mConnectionThread) {
-      NS_ProxyRelease(mConnectionThread, mConnection, PR_TRUE);
-    }
-    else {
-      NS_ERROR("Leaking connection!");
-      mozIStorageConnection* leak;
-      mConnection.forget(&leak);
-    }
-  }
-}
-
 bool
 IDBDatabase::IsQuotaDisabled()
 {
@@ -415,7 +370,6 @@ IDBDatabase::Invalidate()
   }
 
   PR_AtomicSet(&mInvalidated, 1);
-  CloseConnection();
 
   DatabaseInfo* info;
   if (!DatabaseInfo::Get(mDatabaseId, &info)) {
@@ -448,7 +402,6 @@ NS_IMPL_CYCLE_COLLECTION_UNLINK_END
 
 NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION_INHERITED(IDBDatabase)
   NS_INTERFACE_MAP_ENTRY(nsIIDBDatabase)
-  NS_INTERFACE_MAP_ENTRY(nsIObserver)
   NS_DOM_INTERFACE_MAP_ENTRY_CLASSINFO(IDBDatabase)
 NS_INTERFACE_MAP_END_INHERITING(nsDOMEventTargetHelper)
 
@@ -653,6 +606,10 @@ IDBDatabase::Transaction(nsIVariant* aStoreNames,
 {
   NS_ASSERTION(NS_IsMainThread(), "Wrong thread!");
 
+  if (IndexedDatabaseManager::IsShuttingDown()) {
+    return NS_ERROR_ILLEGAL_DURING_SHUTDOWN;
+  }
+
   if (aOptionalArgCount) {
     if (aMode != nsIIDBTransaction::READ_WRITE &&
         aMode != nsIIDBTransaction::READ_ONLY &&
@@ -831,19 +788,6 @@ IDBDatabase::ObjectStore(const nsAString& aName,
   return NS_OK;
 }
 
-NS_IMETHODIMP
-IDBDatabase::Observe(nsISupports* aSubject,
-                     const char* aTopic,
-                     const PRUnichar* aData)
-{
-  NS_ASSERTION(NS_IsMainThread(), "Wrong thread!");
-  NS_ENSURE_FALSE(strcmp(aTopic, IDLE_THREAD_TOPIC), NS_ERROR_UNEXPECTED);
-
-  CloseConnection();
-
-  return NS_OK;
-}
-
 PRUint16
 SetVersionHelper::DoDatabaseWork(mozIStorageConnection* aConnection)
 {

dom/indexedDB/IDBDatabase.h

@@ -41,16 +41,13 @@
 #define mozilla_dom_indexeddb_idbdatabase_h__
 
 #include "mozilla/dom/indexedDB/IndexedDatabase.h"
-#include "mozilla/dom/indexedDB/LazyIdleThread.h"
 
 #include "nsIIDBDatabase.h"
-#include "nsIObserver.h"
 
 #include "nsCycleCollectionParticipant.h"
 #include "nsDOMEventTargetHelper.h"
 #include "nsDOMLists.h"
 
-class mozIStorageConnection;
 class nsIScriptContext;
 class nsPIDOMWindow;
 
@@ -59,17 +56,17 @@ BEGIN_INDEXEDDB_NAMESPACE
 class AsyncConnectionHelper;
 struct DatabaseInfo;
 class IDBTransaction;
+class IndexedDatabaseManager;
 
 class IDBDatabase : public nsDOMEventTargetHelper,
-                    public nsIIDBDatabase,
+                    public nsIIDBDatabase
-                    public nsIObserver
 {
   friend class AsyncConnectionHelper;
+  friend class IndexedDatabaseManager;
 
 public:
   NS_DECL_ISUPPORTS_INHERITED
   NS_DECL_NSIIDBDATABASE
-  NS_DECL_NSIOBSERVER
 
   NS_DECL_CYCLE_COLLECTION_CLASS_INHERITED(IDBDatabase,
                                            nsDOMEventTargetHelper)
@@ -78,17 +75,8 @@ public:
   Create(nsIScriptContext* aScriptContext,
          nsPIDOMWindow* aOwner,
          DatabaseInfo* aDatabaseInfo,
-         LazyIdleThread* aThread,
-         nsCOMPtr<mozIStorageConnection>& aConnection,
          const nsACString& aASCIIOrigin);
 
-  nsIThread* ConnectionThread()
-  {
-    return mConnectionThread;
-  }
-
-  void CloseConnection();
-
   PRUint32 Id()
   {
     return mDatabaseId;
@@ -111,8 +99,7 @@ public:
     return mOwner;
   }
 
-  bool
+  bool IsQuotaDisabled();
-  IsQuotaDisabled();
 
   nsCString& Origin()
   {
@@ -126,21 +113,13 @@ private:
   IDBDatabase();
   ~IDBDatabase();
 
-  // Only meant to be called on mStorageThread!
-  nsresult GetOrCreateConnection(mozIStorageConnection** aConnection);
-
   PRUint32 mDatabaseId;
   nsString mName;
   nsString mDescription;
   nsString mFilePath;
   nsCString mASCIIOrigin;
   PRInt32 mInvalidated;
-
+  bool mRegistered;
-  nsRefPtr<LazyIdleThread> mConnectionThread;
-
-  // Only touched on mStorageThread! These must be destroyed in the
-  // FireCloseConnectionRunnable method.
-  nsCOMPtr<mozIStorageConnection> mConnection;
 
   // Only touched on the main thread.
   nsRefPtr<nsDOMEventListenerWrapper> mOnErrorListener;

dom/indexedDB/IDBFactory.cpp

@@ -128,30 +128,24 @@ public:
   OpenDatabaseHelper(IDBRequest* aRequest,
                      const nsAString& aName,
                      const nsAString& aDescription,
-                     const nsACString& aASCIIOrigin,
+                     const nsACString& aASCIIOrigin)
-                     LazyIdleThread* aThread)
   : AsyncConnectionHelper(static_cast<IDBDatabase*>(nsnull), aRequest),
     mName(aName), mDescription(aDescription), mASCIIOrigin(aASCIIOrigin),
-    mThread(aThread), mDatabaseId(0)
+    mDatabaseId(0)
   { }
 
   PRUint16 DoDatabaseWork(mozIStorageConnection* aConnection);
   PRUint16 GetSuccessResult(nsIWritableVariant* aResult);
 
 private:
-  PRUint16 DoDatabaseWorkInternal(mozIStorageConnection* aConnection);
-
   // In-params.
   nsString mName;
   nsString mDescription;
   nsCString mASCIIOrigin;
-  nsRefPtr<LazyIdleThread> mThread;
 
   // Out-params.
   nsTArray<nsAutoPtr<ObjectStoreInfo> > mObjectStores;
   nsString mVersion;
-
-  nsCOMPtr<mozIStorageConnection> mConnection;
   nsString mDatabaseFilePath;
   PRUint32 mDatabaseId;
 };
@@ -718,14 +712,11 @@ IDBFactory::Open(const nsAString& aName,
   nsRefPtr<IDBRequest> request = IDBRequest::Create(this, context, innerWindow);
   NS_ENSURE_TRUE(request, NS_ERROR_FAILURE);
 
-  nsRefPtr<LazyIdleThread> thread(new LazyIdleThread(kDefaultThreadTimeoutMS,
-                                                     nsnull));
-
   nsRefPtr<OpenDatabaseHelper> openHelper =
-    new OpenDatabaseHelper(request, aName, aDescription, origin, thread);
+    new OpenDatabaseHelper(request, aName, aDescription, origin);
 
   nsRefPtr<CheckPermissionsHelper> permissionHelper =
-    new CheckPermissionsHelper(openHelper, thread, innerWindow, origin);
+    new CheckPermissionsHelper(openHelper, innerWindow, origin);
 
   nsRefPtr<IndexedDatabaseManager> mgr = IndexedDatabaseManager::GetOrCreate();
   NS_ENSURE_TRUE(mgr, NS_ERROR_FAILURE);
@@ -839,30 +830,26 @@ IDBFactory::MakeBoundKeyRange(nsIVariant* aLeft,
 
 PRUint16
 OpenDatabaseHelper::DoDatabaseWork(mozIStorageConnection* aConnection)
-{
-  PRUint16 result = DoDatabaseWorkInternal(aConnection);
-  if (result != OK) {
-    mConnection = nsnull;
-  }
-  return result;
-}
-
-PRUint16
-OpenDatabaseHelper::DoDatabaseWorkInternal(mozIStorageConnection* aConnection)
 {
 #ifdef DEBUG
   {
     PRBool correctThread;
-    NS_ASSERTION(NS_SUCCEEDED(mThread->IsOnCurrentThread(&correctThread)) &&
+    NS_ASSERTION(NS_SUCCEEDED(IndexedDatabaseManager::Get()->IOThread()->
+                              IsOnCurrentThread(&correctThread)) &&
                  correctThread,
                  "Running on the wrong thread!");
   }
 #endif
   NS_ASSERTION(!aConnection, "Huh?!");
 
+  if (IndexedDatabaseManager::IsShuttingDown()) {
+    return nsIIDBDatabaseException::UNKNOWN_ERR;
+  }
+
+  nsCOMPtr<mozIStorageConnection> connection;
   nsresult rv = CreateDatabaseConnection(mASCIIOrigin, mName, mDescription,
                                          mDatabaseFilePath,
-                                         getter_AddRefs(mConnection));
+                                         getter_AddRefs(connection));
   NS_ENSURE_SUCCESS(rv, nsIIDBDatabaseException::UNKNOWN_ERR);
 
   mDatabaseId = HashString(mDatabaseFilePath);
@@ -872,7 +859,7 @@ OpenDatabaseHelper::DoDatabaseWorkInternal(mozIStorageConnection* aConnection)
 
   { // Load object store names and ids.
     nsCOMPtr<mozIStorageStatement> stmt;
-    rv = mConnection->CreateStatement(NS_LITERAL_CSTRING(
+    rv = connection->CreateStatement(NS_LITERAL_CSTRING(
       "SELECT name, id, key_path, auto_increment "
       "FROM object_store"
     ), getter_AddRefs(stmt));
@@ -910,7 +897,7 @@ OpenDatabaseHelper::DoDatabaseWorkInternal(mozIStorageConnection* aConnection)
 
   { // Load index information
     nsCOMPtr<mozIStorageStatement> stmt;
-    rv = mConnection->CreateStatement(NS_LITERAL_CSTRING(
+    rv = connection->CreateStatement(NS_LITERAL_CSTRING(
       "SELECT object_store_id, id, name, key_path, unique_index, "
              "object_store_autoincrement "
       "FROM object_store_index"
@@ -951,7 +938,7 @@ OpenDatabaseHelper::DoDatabaseWorkInternal(mozIStorageConnection* aConnection)
 
   { // Load version information.
     nsCOMPtr<mozIStorageStatement> stmt;
-    rv = mConnection->CreateStatement(NS_LITERAL_CSTRING(
+    rv = connection->CreateStatement(NS_LITERAL_CSTRING(
       "SELECT version "
       "FROM database"
     ), getter_AddRefs(stmt));
@@ -975,8 +962,6 @@ OpenDatabaseHelper::DoDatabaseWorkInternal(mozIStorageConnection* aConnection)
 PRUint16
 OpenDatabaseHelper::GetSuccessResult(nsIWritableVariant* aResult)
 {
-  NS_ASSERTION(mConnection, "Should have a connection!");
-
   DatabaseInfo* dbInfo;
   if (DatabaseInfo::Get(mDatabaseId, &dbInfo)) {
     NS_ASSERTION(dbInfo->referenceCount, "Bad reference count!");
@@ -1064,10 +1049,10 @@ OpenDatabaseHelper::GetSuccessResult(nsIWritableVariant* aResult)
 
   nsRefPtr<IDBDatabase> db =
     IDBDatabase::Create(mRequest->ScriptContext(), mRequest->Owner(), dbInfo,
-                        mThread, mConnection, mASCIIOrigin);
+                        mASCIIOrigin);
-  NS_ASSERTION(db, "This can't fail!");
+  if (!db) {
-
+    return nsIIDBDatabaseException::UNKNOWN_ERR;
-  NS_ASSERTION(!mConnection, "Should have swapped out!");
+  }
 
   aResult->SetAsISupports(static_cast<nsPIDOMEventTarget*>(db));
   return OK;

dom/indexedDB/IDBTransaction.h

@@ -53,6 +53,7 @@
 #include "nsHashKeys.h"
 #include "nsInterfaceHashtable.h"
 
+class mozIStorageConnection;
 class mozIStorageStatement;
 class nsIThread;
 

dom/indexedDB/IndexedDatabaseManager.cpp

@@ -68,7 +68,7 @@ using namespace mozilla::services;
 
 namespace {
 
-bool gShutdown = false;
+PRInt32 gShutdown = 0;
 
 // Does not hold a reference.
 IndexedDatabaseManager* gInstance = nsnull;
@@ -116,7 +116,7 @@ IndexedDatabaseManager::GetOrCreate()
 {
   NS_ASSERTION(NS_IsMainThread(), "Wrong thread!");
 
-  if (gShutdown) {
+  if (IsShuttingDown()) {
     NS_ERROR("Calling GetOrCreateInstance() after shutdown!");
     return nsnull;
   }
@@ -153,7 +153,8 @@ IndexedDatabaseManager::GetOrCreate()
 
     // Make a lazy thread for any IO we need (like clearing or enumerating the
     // contents of indexedDB database directories).
-    instance->mIOThread = new LazyIdleThread(DEFAULT_THREAD_TIMEOUT_MS);
+    instance->mIOThread = new LazyIdleThread(DEFAULT_THREAD_TIMEOUT_MS,
+                                             LazyIdleThread::ManualShutdown);
 
     // The observer service will hold our last reference, don't AddRef here.
     gInstance = instance;
@@ -187,7 +188,7 @@ IndexedDatabaseManager::RegisterDatabase(IDBDatabase* aDatabase)
   NS_ASSERTION(aDatabase, "Null pointer!");
 
   // Don't allow any new databases to be created after shutdown.
-  if (gShutdown) {
+  if (IsShuttingDown()) {
     return false;
   }
 
@@ -205,6 +206,8 @@ IndexedDatabaseManager::RegisterDatabase(IDBDatabase* aDatabase)
     NS_WARNING("Out of memory?");
     return false;
   }
+
+  aDatabase->mRegistered = true;
   return true;
 }
 
@@ -287,6 +290,13 @@ IndexedDatabaseManager::WaitForClearAndDispatch(const nsACString& aOrigin,
   return NS_DispatchToCurrentThread(aRunnable);
 }
 
+// static
+bool
+IndexedDatabaseManager::IsShuttingDown()
+{
+  return !!gShutdown;
+}
+
 NS_IMPL_ISUPPORTS2(IndexedDatabaseManager, nsIIndexedDatabaseManager,
                                            nsIObserver)
 
@@ -445,9 +455,11 @@ IndexedDatabaseManager::Observe(nsISupports* aSubject,
   NS_ASSERTION(NS_IsMainThread(), "Wrong thread!");
 
   if (!strcmp(aTopic, NS_XPCOM_SHUTDOWN_THREADS_OBSERVER_ID)) {
-    // Setting this flag prevents the servic from being recreated and prevents
+    // Setting this flag prevents the service from being recreated and prevents
     // further databases from being created.
-    gShutdown = true;
+    if (PR_AtomicSet(&gShutdown, 1)) {
+      NS_ERROR("Shutdown more than once?!");
+    }
 
     // Make sure to join with our IO thread.
     if (NS_FAILED(mIOThread->Shutdown())) {

dom/indexedDB/IndexedDatabaseManager.h

@@ -80,6 +80,14 @@ public:
   nsresult WaitForClearAndDispatch(const nsACString& aOrigin,
                                    nsIRunnable* aRunnable);
 
+  nsIThread* IOThread()
+  {
+    NS_ASSERTION(mIOThread, "This should never be null!");
+    return mIOThread;
+  }
+
+  static bool IsShuttingDown();
+
 private:
   IndexedDatabaseManager();
   ~IndexedDatabaseManager();

dom/indexedDB/LazyIdleThread.cpp

@@ -64,6 +64,7 @@ USING_INDEXEDDB_NAMESPACE
 using mozilla::MutexAutoLock;
 
 LazyIdleThread::LazyIdleThread(PRUint32 aIdleTimeoutMS,
+                               ShutdownMethod aShutdownMethod,
                                nsIObserver* aIdleObserver)
 : mMutex("LazyIdleThread::mMutex"),
   mOwningThread(NS_GetCurrentThread()),
@@ -71,6 +72,7 @@ LazyIdleThread::LazyIdleThread(PRUint32 aIdleTimeoutMS,
   mIdleTimeoutMS(aIdleTimeoutMS),
   mPendingEventCount(0),
   mIdleNotificationCount(0),
+  mShutdownMethod(aShutdownMethod),
   mShutdown(PR_FALSE),
   mThreadIsShuttingDown(PR_FALSE),
   mIdleTimeoutEnabled(PR_TRUE)
@@ -172,7 +174,7 @@ LazyIdleThread::EnsureThread()
 
   nsresult rv;
 
-  if (NS_IsMainThread()) {
+  if (mShutdownMethod == AutomaticShutdown && NS_IsMainThread()) {
     nsCOMPtr<nsIObserverService> obs =
       do_GetService(NS_OBSERVERSERVICE_CONTRACTID, &rv);
     NS_ENSURE_SUCCESS(rv, rv);
@@ -257,7 +259,7 @@ LazyIdleThread::ShutdownThread()
   nsresult rv;
 
   if (mThread) {
-    if (NS_IsMainThread()) {
+    if (mShutdownMethod == AutomaticShutdown && NS_IsMainThread()) {
       nsCOMPtr<nsIObserverService> obs =
         do_GetService(NS_OBSERVERSERVICE_CONTRACTID);
       NS_WARN_IF_FALSE(obs, "Failed to get observer service!");
@@ -504,8 +506,10 @@ LazyIdleThread::Observe(nsISupports* /* aSubject */,
                         const PRUnichar* /* aData */)
 {
   NS_ASSERTION(NS_IsMainThread(), "Wrong thread!");
-  NS_ENSURE_FALSE(strcmp("xpcom-shutdown-threads", aTopic),
+  NS_ASSERTION(mShutdownMethod == AutomaticShutdown,
-                  NS_ERROR_UNEXPECTED);
+               "Should not receive notifications if not AutomaticShutdown!");
+  NS_ASSERTION(!strcmp("xpcom-shutdown-threads", aTopic), "Bad topic!");
+
   Shutdown();
   return NS_OK;
 }

dom/indexedDB/LazyIdleThread.h

@@ -72,11 +72,17 @@ public:
   NS_DECL_NSITHREADOBSERVER
   NS_DECL_NSIOBSERVER
 
+  enum ShutdownMethod {
+    AutomaticShutdown = 0,
+    ManualShutdown
+  };
+
   /**
    * Create a new LazyIdleThread that will destroy its thread after the given
    * number of milliseconds.
    */
   LazyIdleThread(PRUint32 aIdleTimeoutMS,
+                 ShutdownMethod aShutdownMethod = AutomaticShutdown,
                  nsIObserver* aIdleObserver = nsnull);
 
   /**
@@ -191,6 +197,13 @@ private:
    */
   PRUint32 mIdleNotificationCount;
 
+  /**
+   * Whether or not the thread should automatically shutdown. If the owner
+   * specified ManualShutdown at construction time then the owner should take
+   * care to call Shutdown() manually when appropriate.
+   */
+  ShutdownMethod mShutdownMethod;
+
   /**
    * Only accessed on the owning thread. Set to true when Shutdown() has been
    * called and prevents EnsureThread() from recreating mThread.