Revert 195482 "Make DriveSystemService an observer of DriveNotif..."

trunk/src/chrome/browser/sync_file_system/drive_file_sync_service.cc

Index: trunk/src/chrome/browser/sync_file_system/drive_file_sync_service.cc
===================================================================
--- trunk/src/chrome/browser/sync_file_system/drive_file_sync_service.cc	(revision 195487)
+++ trunk/src/chrome/browser/sync_file_system/drive_file_sync_service.cc	(working copy)
@@ -46,6 +46,14 @@
 const base::FilePath::CharType kSyncFileSystemDir[] =
     FILE_PATH_LITERAL("Sync FileSystem");
 
+// Incremental sync polling interval.
+// TODO(calvinlo): Improve polling algorithm dependent on whether push
+// notifications are on or off.
+const int64 kMinimumPollingDelaySeconds = 5;
+const int64 kMaximumPollingDelaySeconds = 10 * 60;  // 10 min
+const int64 kPollingDelaySecondsWithNotification = 4 * 60 * 60;  // 4 hr
+const double kDelayMultiplier = 1.6;
+
 bool CreateTemporaryFile(const base::FilePath& dir_path,
                          base::FilePath* temp_file) {
   return file_util::CreateDirectory(dir_path) &&
@@ -267,6 +275,7 @@
       state_(REMOTE_SERVICE_OK),
       sync_enabled_(true),
       largest_fetched_changestamp_(0),
+      polling_delay_seconds_(kMinimumPollingDelaySeconds),
       may_have_unfetched_changes_(false),
       remote_change_processor_(NULL),
       conflict_resolution_(kDefaultPolicy),
@@ -559,6 +568,11 @@
   FOR_EACH_OBSERVER(
       Observer, service_observers_,
       OnRemoteServiceStateUpdated(GetCurrentState(), status_message));
+
+  if (GetCurrentState() == REMOTE_SERVICE_OK) {
+    UpdatePollingDelay(kMinimumPollingDelaySeconds);
+    SchedulePolling();
+  }
 }
 
 SyncStatusCode DriveFileSyncService::SetConflictResolutionPolicy(
@@ -629,6 +643,7 @@
   FOR_EACH_OBSERVER(
       Observer, service_observers_,
       OnRemoteServiceStateUpdated(GetCurrentState(), "Authenticated"));
+  UpdatePollingDelay(kMinimumPollingDelaySeconds);
 
   may_have_unfetched_changes_ = true;
   MaybeStartFetchChanges();
@@ -644,6 +659,7 @@
   FOR_EACH_OBSERVER(
       Observer, service_observers_,
       OnRemoteServiceStateUpdated(GetCurrentState(), "Network connected"));
+  UpdatePollingDelay(kMinimumPollingDelaySeconds);
 
   may_have_unfetched_changes_ = true;
   MaybeStartFetchChanges();
@@ -660,6 +676,7 @@
       state_(REMOTE_SERVICE_OK),
       sync_enabled_(true),
       largest_fetched_changestamp_(0),
+      polling_delay_seconds_(-1),
       may_have_unfetched_changes_(false),
       remote_change_processor_(NULL),
       conflict_resolution_(kDefaultPolicy),
@@ -710,6 +727,10 @@
     RemoteServiceState old_state = GetCurrentState();
     UpdateServiceState();
 
+    // Reset the polling delay. This will adjust the polling timer
+    // based on the current service state.
+    UpdatePollingDelay(polling_delay_seconds_);
+
     // Notify remote sync service state if the state has been changed.
     if (!token_->description().empty() || old_state != GetCurrentState()) {
       FOR_EACH_OBSERVER(
@@ -732,6 +753,8 @@
 
   MaybeStartFetchChanges();
 
+  SchedulePolling();
+
   // Notify observer of the update of |pending_changes_|.
   FOR_EACH_OBSERVER(Observer, service_observers_,
                     OnRemoteChangeQueueUpdated(pending_changes_.size()));
@@ -1001,8 +1024,7 @@
     metadata_store_->MoveBatchSyncOriginToIncremental(origin);
   }
 
-  may_have_unfetched_changes_ = true;
-  MaybeStartFetchChanges();
+  CheckForUpdates();
   NotifyTaskDone(SYNC_STATUS_OK, token.Pass());
 }
 
@@ -2085,7 +2107,7 @@
   }
 }
 
-void DriveFileSyncService::OnNotificationReceived() {
+void DriveFileSyncService::CheckForUpdates() {
   // TODO(calvinlo): Try to eliminate may_have_unfetched_changes_ variable.
   may_have_unfetched_changes_ = true;
   MaybeStartFetchChanges();
@@ -2175,6 +2197,15 @@
   if (!changes->entries().empty())
     largest_fetched_changestamp_ = changes->entries().back()->changestamp();
 
+  if (has_new_changes) {
+    UpdatePollingDelay(kMinimumPollingDelaySeconds);
+  } else {
+    // If the change_queue_ was not updated, update the polling delay to wait
+    // longer.
+    UpdatePollingDelay(static_cast<int64>(
+        kDelayMultiplier * polling_delay_seconds_));
+  }
+
   NotifyTaskDone(SYNC_STATUS_OK, token.Pass());
 }
 
@@ -2206,6 +2237,49 @@
   return false;
 }
 
+void DriveFileSyncService::SchedulePolling() {
+  if (polling_timer_.IsRunning() ||
+      polling_delay_seconds_ < 0 ||
+      GetCurrentState() == REMOTE_SERVICE_DISABLED)
+    return;
+
+  DVLOG(1) << "Polling scheduled"
+           << " (delay:" << polling_delay_seconds_ << "s)";
+
+  polling_timer_.Start(
+      FROM_HERE, base::TimeDelta::FromSeconds(polling_delay_seconds_),
+      base::Bind(&DriveFileSyncService::OnPollingTimerFired, AsWeakPtr()));
+}
+
+void DriveFileSyncService::OnPollingTimerFired() {
+  may_have_unfetched_changes_ = true;
+  MaybeStartFetchChanges();
+}
+
+void DriveFileSyncService::UpdatePollingDelay(int64 new_delay_sec) {
+  // polling_delay_seconds_ made negative to disable polling for testing.
+  if (polling_delay_seconds_ < 0)
+    return;
+
+  if (state_ == REMOTE_SERVICE_TEMPORARY_UNAVAILABLE) {
+    // If the service state is TEMPORARY_UNAVAILABLE, poll the service
+    // with a modest duration (but more frequently than
+    // kPollingDelaySecondsWithNotification) so that we have a mild chance
+    // to recover the state.
+    polling_delay_seconds_ = kMaximumPollingDelaySeconds;
+    polling_timer_.Stop();
+    return;
+  }
+
+  int64 old_delay = polling_delay_seconds_;
+
+  // Push notifications off.
+  polling_delay_seconds_ = std::min(new_delay_sec, kMaximumPollingDelaySeconds);
+
+  if (polling_delay_seconds_ < old_delay)
+    polling_timer_.Stop();
+}
+
 void DriveFileSyncService::NotifyObserversFileStatusChanged(
     const FileSystemURL& url,
     SyncFileStatus sync_status,