gdata: Implement periodic file system update checks.

chrome/browser/chromeos/extensions/file_browser_event_router.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/chromeos/extensions/file_browser_event_router.h"
 
 #include "base/bind.h"
 #include "base/json/json_writer.h"
 #include "base/message_loop.h"
 #include "base/stl_util.h"
@@ skipping 148 matching lines @@
                                         extension_id,
                                         is_remote_watch));
 
     if (watch->Watch(watch_path, delegate_.get()))
       file_watchers_[watch_path] = watch.release();
     else
       return false;
   } else {
     iter->second->AddExtension(extension_id);
   }
+  if (is_remote_watch) {
+    gdata::GDataFileSystem* file_system = GetFileSystem();

[satorux1, 2012/05/03 19:41:34]

Per your comment, we are not on UI thread here? If so, on what thread we are
now? Please annotate with 

DCHECK(BrowserThread::CurrentlyOn(BrowserThread::XXX));

at the beginning of this function.

[hshi, 2012/05/03 21:17:49]

Done.

+    if (file_system)
+      file_system->RequestStartUpdates();

[satorux1, 2012/05/03 19:44:54]

I have another idea. 

Wouldn't it be simpler just to call this when FileBrowserEventRouter is created,
and call RequestStopUpdates() when the router is deleted?

[satorux1, 2012/05/03 19:47:41]

I was assuming that FileBrowserEventRouter is created when the file manager is
opened, and deleted when the file manager is closed. I may be wrong.

[zel, 2012/05/03 19:54:30]

Lifetime of FileBrowserEventRouter is RefcountedProfileKeyedService - it's
lifetime is linked to the Profile, so we surely don't want to start monitoring
updates as soon as it gets created.

[hshi, 2012/05/03 21:17:49]

I have moved this logic out to a separate task on the UI thread.

+  }
   return true;
 }
 
 void FileBrowserEventRouter::RemoveFileWatch(
     const FilePath& local_path,
     const std::string& extension_id) {
   base::AutoLock lock(lock_);
   FilePath watch_path = local_path;
   // Tweak watch path for remote sources - we need to drop leading /special
   // directory from there in order to be able to pair these events with
   // their change notifications.
   if (gdata::util::GetSpecialRemoteRootPath().IsParent(watch_path)) {
     watch_path = gdata::util::ExtractGDataPath(watch_path);
+    gdata::GDataFileSystem* file_system = GetFileSystem();
+    if (file_system)
+      file_system->RequestStopUpdates();
   }
   WatcherMap::iterator iter = file_watchers_.find(watch_path);
   if (iter == file_watchers_.end())
     return;
   // Remove the renderer process for this watch.
   iter->second->RemoveExtension(extension_id);
   if (iter->second->GetRefCount() == 0) {
     delete iter->second;
     file_watchers_.erase(iter);
   }
@@ skipping 56 matching lines @@
      notifications_->ManageNotificationsOnMountCompleted(
         disk->system_path_prefix(), disk->drive_label(), disk->is_parent(),
         error_code == chromeos::MOUNT_ERROR_NONE,
         error_code == chromeos::MOUNT_ERROR_UNSUPORTED_FILESYSTEM);
   } else if (mount_info.mount_type == chromeos::MOUNT_TYPE_ARCHIVE) {
     // Clear the "mounted" state for archive files in gdata cache
     // when mounting failed or unmounting succeeded.
     if ((event_type == DiskMountManager::MOUNTING) !=
         (error_code == chromeos::MOUNT_ERROR_NONE)) {
       FilePath source_path(mount_info.source_path);
-      gdata::GDataSystemService* system_service =
-          gdata::GDataSystemServiceFactory::GetForProfile(profile_);
-      gdata::GDataFileSystem* file_system =
-          system_service ? system_service->file_system() : NULL;
+      gdata::GDataFileSystem* file_system = GetFileSystem();
       if (file_system && file_system->IsUnderGDataCacheDirectory(source_path))
         file_system->SetMountedState(source_path, false,
                                      gdata::SetMountedStateCallback());
     }
   }
 }
 
 void FileBrowserEventRouter::OnProgressUpdate(
     const std::vector<gdata::GDataOperationRegistry::ProgressStatus>& list) {
   scoped_ptr<ListValue> event_list(
@@ skipping 322 matching lines @@
 unsigned int
 FileBrowserEventRouter::FileWatcherExtensions::GetRefCount() const {
   return ref_count_;
 }
 
 const FilePath&
 FileBrowserEventRouter::FileWatcherExtensions::GetVirtualPath() const {
   return virtual_path_;
 }
 
+gdata::GDataFileSystem* FileBrowserEventRouter::GetFileSystem() const {
+  gdata::GDataSystemService* system_service =
+      gdata::GDataSystemServiceFactory::GetForProfile(profile_);
+  return (system_service ? system_service->file_system() : NULL);
+}
+
 bool FileBrowserEventRouter::FileWatcherExtensions::Watch
     (const FilePath& path, FileWatcherDelegate* delegate) {
   if (is_remote_file_system_)
     return true;
 
   return file_watcher_->Watch(path, delegate);
 }
 
 // static
 scoped_refptr<FileBrowserEventRouter>
@@ skipping 22 matching lines @@
   return scoped_refptr<RefcountedProfileKeyedService>(
       new FileBrowserEventRouter(profile));
 }
 
 bool FileBrowserEventRouterFactory::ServiceHasOwnInstanceInIncognito() {
   // Explicitly and always allow this router in guest login mode.   see
   // chrome/browser/profiles/profile_keyed_base_factory.h comment
   // for the details.
   return true;
 }