[Sync] Avoid unregistering object IDs on shutdown

chrome/browser/sync/glue/chrome_sync_notification_bridge.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/sync/glue/chrome_sync_notification_bridge.h"
 
 #include "base/bind.h"
 #include "base/location.h"
+#include "base/logging.h"
+#include "base/memory/scoped_ptr.h"
 #include "chrome/common/chrome_notification_types.h"
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/notification_service.h"
 #include "sync/notifier/sync_notifier_helper.h"
 #include "sync/notifier/sync_notifier_observer.h"
 
 using content::BrowserThread;
 
 namespace browser_sync {
 
 class ChromeSyncNotificationBridge::Core
     : public base::RefCountedThreadSafe<Core> {
  public:
   // Created on UI thread.
   explicit Core(
       const scoped_refptr<base::SequencedTaskRunner>& sync_task_runner);
 
   // All member functions below must be called on the sync task runner.
 
+  void InitializeOnSyncThread();
+  void DestroyOnSyncThread();

[tim (not reviewing), 2012/08/06 05:55:32]

Is 'Destroy' the right name?  This won't necessarily result in calling the
destructor. 

[akalin, 2012/08/07 07:25:19]

Done, use Cleanup

+
   void UpdateEnabledTypes(syncer::ModelTypeSet enabled_types);
-  void UpdateRegisteredIds(syncer::SyncNotifierObserver* handler,
+  void SetHandler(const std::string& handler_name,
+                  syncer::SyncNotifierObserver* handler);
+  void UpdateRegisteredIds(const std::string& handler_name,
                            const syncer::ObjectIdSet& ids);
 
   void EmitNotification(
       const syncer::ModelTypePayloadMap& payload_map,
       syncer::IncomingNotificationSource notification_source);
 
  private:
   friend class base::RefCountedThreadSafe<Core>;
 
   // Destroyed on the UI thread or on |sync_task_runner_|.
   ~Core();
 
   const scoped_refptr<base::SequencedTaskRunner> sync_task_runner_;
 
   // Used only on |sync_task_runner_|.
   syncer::ModelTypeSet enabled_types_;
-  syncer::SyncNotifierHelper helper_;
+  scoped_ptr<syncer::SyncNotifierHelper> helper_;
 };
 
 ChromeSyncNotificationBridge::Core::Core(
     const scoped_refptr<base::SequencedTaskRunner>& sync_task_runner)
-    : sync_task_runner_(sync_task_runner) {
+    : sync_task_runner_(sync_task_runner),
+      helper_(NULL) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   DCHECK(sync_task_runner_.get());
 }
 
 ChromeSyncNotificationBridge::Core::~Core() {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI) ||
          sync_task_runner_->RunsTasksOnCurrentThread());
+  DCHECK(!helper_.get());
+}
+
+void ChromeSyncNotificationBridge::Core::InitializeOnSyncThread() {
+  helper_.reset(new syncer::SyncNotifierHelper());
+}
+
+void ChromeSyncNotificationBridge::Core::DestroyOnSyncThread() {
+  helper_.reset();
 }
 
 void ChromeSyncNotificationBridge::Core::UpdateEnabledTypes(
     syncer::ModelTypeSet types) {
   DCHECK(sync_task_runner_->RunsTasksOnCurrentThread());
   enabled_types_ = types;
 }
 
+void ChromeSyncNotificationBridge::Core::SetHandler(
+    const std::string& handler_name,
+    syncer::SyncNotifierObserver* handler) {
+  DCHECK(sync_task_runner_->RunsTasksOnCurrentThread());
+  helper_->SetHandler(handler_name, handler);
+}
+
 void ChromeSyncNotificationBridge::Core::UpdateRegisteredIds(
-    syncer::SyncNotifierObserver* handler,
+    const std::string& handler_name,
     const syncer::ObjectIdSet& ids) {
   DCHECK(sync_task_runner_->RunsTasksOnCurrentThread());
-  helper_.UpdateRegisteredIds(handler, ids);
+  helper_->UpdateRegisteredIds(handler_name, ids);
 }
 
 void ChromeSyncNotificationBridge::Core::EmitNotification(
     const syncer::ModelTypePayloadMap& payload_map,
     syncer::IncomingNotificationSource notification_source) {
   DCHECK(sync_task_runner_->RunsTasksOnCurrentThread());
   const syncer::ModelTypePayloadMap& effective_payload_map =
       payload_map.empty() ?
       syncer::ModelTypePayloadMapFromEnumSet(enabled_types_, std::string()) :
       payload_map;
 
-  helper_.DispatchInvalidationsToHandlers(
+  helper_->DispatchInvalidationsToHandlers(
       ModelTypePayloadMapToObjectIdPayloadMap(effective_payload_map),
       notification_source);
 }
 
 ChromeSyncNotificationBridge::ChromeSyncNotificationBridge(
     const Profile* profile,
     const scoped_refptr<base::SequencedTaskRunner>& sync_task_runner)
     : sync_task_runner_(sync_task_runner),
       core_(new Core(sync_task_runner_)) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   DCHECK(profile);
   registrar_.Add(this, chrome::NOTIFICATION_SYNC_REFRESH_LOCAL,
                  content::Source<Profile>(profile));
   registrar_.Add(this, chrome::NOTIFICATION_SYNC_REFRESH_REMOTE,
                  content::Source<Profile>(profile));
+
+  if (!sync_task_runner_->PostTask(
+          FROM_HERE, base::Bind(&Core::InitializeOnSyncThread, core_))) {
+    NOTREACHED();
+  }
 }
 
 ChromeSyncNotificationBridge::~ChromeSyncNotificationBridge() {}
 
+void ChromeSyncNotificationBridge::StopForShutdown() {
+  if (!sync_task_runner_->PostTask(
+          FROM_HERE, base::Bind(&Core::DestroyOnSyncThread, core_))) {
+    NOTREACHED();
+  }
+}
+
 void ChromeSyncNotificationBridge::UpdateEnabledTypes(
     syncer::ModelTypeSet types) {
   DCHECK(sync_task_runner_->RunsTasksOnCurrentThread());
   core_->UpdateEnabledTypes(types);
 }
 
+void ChromeSyncNotificationBridge::SetHandler(
+    const std::string& handler_name,
+    syncer::SyncNotifierObserver* handler) {
+  DCHECK(sync_task_runner_->RunsTasksOnCurrentThread());
+  core_->SetHandler(handler_name, handler);
+}
+
 void ChromeSyncNotificationBridge::UpdateRegisteredIds(
-    syncer::SyncNotifierObserver* handler,
+    const std::string& handler_name,
     const syncer::ObjectIdSet& ids) {
   DCHECK(sync_task_runner_->RunsTasksOnCurrentThread());
-  core_->UpdateRegisteredIds(handler, ids);
+  core_->UpdateRegisteredIds(handler_name, ids);
 }
 
 void ChromeSyncNotificationBridge::Observe(
     int type,
     const content::NotificationSource& source,
     const content::NotificationDetails& details) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 
   syncer::IncomingNotificationSource notification_source;
   if (type == chrome::NOTIFICATION_SYNC_REFRESH_LOCAL) {
     notification_source = syncer::LOCAL_NOTIFICATION;
   } else if (type == chrome::NOTIFICATION_SYNC_REFRESH_REMOTE) {
     notification_source = syncer::REMOTE_NOTIFICATION;
   } else {
     NOTREACHED() << "Unexpected notification type: " << type;
     return;
   }
 
   content::Details<const syncer::ModelTypePayloadMap>
       payload_details(details);
   const syncer::ModelTypePayloadMap& payload_map = *(payload_details.ptr());
-  sync_task_runner_->PostTask(
-      FROM_HERE,
-      base::Bind(&Core::EmitNotification,
-                 core_, payload_map, notification_source));
+  if (!sync_task_runner_->PostTask(
+          FROM_HERE,
+          base::Bind(&Core::EmitNotification,
+                     core_, payload_map, notification_source))) {
+    NOTREACHED();
+  }
 }
 
 }  // namespace browser_sync