gdata: Implement periodic file system update checks.

chrome/browser/chromeos/gdata/gdata_file_system.cc

Index: chrome/browser/chromeos/gdata/gdata_file_system.cc
diff --git a/chrome/browser/chromeos/gdata/gdata_file_system.cc b/chrome/browser/chromeos/gdata/gdata_file_system.cc
index bd79a7fada83c8cb2e48f257cbe1f9bfb8cc4cde..d829f86d59ade5a46923696656cc3a1e6f6a9182 100644
--- a/chrome/browser/chromeos/gdata/gdata_file_system.cc
+++ b/chrome/browser/chromeos/gdata/gdata_file_system.cc
@@ -77,6 +77,13 @@ const FilePath::CharType kFilesystemProtoFile[] =
     FILE_PATH_LITERAL("file_system.pb");
 const FilePath::CharType kSymLinkToDevNull[] = FILE_PATH_LITERAL("/dev/null");
 
+// GData update check interval (in seconds).
+#ifndef NDEBUG
+const int kGDataUpdateCheckIntervalInSec = 5;
+#else
+const int kGDataUpdateCheckIntervalInSec = 60;
+#endif
+
 // Schedule for dumping root file system proto buffers to disk depending its
 // total protobuffer size in MB.
 typedef struct {
@@ -928,6 +935,8 @@ GDataFileSystem::GDataFileSystem(Profile* profile,
           true /* manual reset */, true /* initially signaled */)),
       cache_initialization_started_(false),
       num_pending_tasks_(0),
+      num_update_requests_(0),
+      update_timer_(true /* retain_user_task */, true /* is_repeating */),
       hide_hosted_docs_(false),
       ui_weak_ptr_factory_(ALLOW_THIS_IN_INITIALIZER_LIST(
           new base::WeakPtrFactory<GDataFileSystem>(this))),
@@ -961,6 +970,18 @@ void GDataFileSystem::Initialize() {
   InitializePreferenceObserver();
 }
 
+void GDataFileSystem::CheckForUpdates() {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  ContentOrigin initial_origin = root_->origin();
+  if (initial_origin == FROM_SERVER) {
+    root_->set_origin(REFRESHING);
+    ReloadFeedFromServerIfNeeded(initial_origin,
+                                 root_->largest_changestamp(),
+                                 root_->GetFilePath(),
+                                 gdata::FindEntryCallback());
+  }
+}
+
 bool GDataFileSystem::SetCacheRootPathForTesting(const FilePath& root_path) {
   if (cache_initialization_started_)
     return false;
@@ -1016,6 +1037,28 @@ void GDataFileSystem::RemoveObserver(Observer* observer) {
   observers_.RemoveObserver(observer);
 }
 
+void GDataFileSystem::RequestStartUpdates() {
+  // Perform an immediate check for updates.
+  CheckForUpdates();
+  ++num_update_requests_;

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

You should move num_update_requests_ logic to FileBrowserEventRouter.

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

Done.

+  if (num_update_requests_ == 1) {
+    // If this is the first StartUpdate request, start timer to periodically
+    // check for updates at the specified intervals.
+    update_timer_.Start(FROM_HERE,
+                        base::TimeDelta::FromSeconds(
+                            kGDataUpdateCheckIntervalInSec),
+                        base::Bind(&GDataFileSystem::CheckForUpdates,
+                            ui_weak_ptr_));
+  }
+}
+
+void GDataFileSystem::RequestStopUpdates() {
+  DCHECK_LE(0, num_update_requests_);
+  --num_update_requests_;
+  if (num_update_requests_ == 0)
+    update_timer_.Stop();
+}
+
 void GDataFileSystem::Authenticate(const AuthStatusCallback& callback) {
   // TokenFetcher, used in DocumentsService, must be run on UI thread.
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
@@ -1066,16 +1109,6 @@ void GDataFileSystem::FindEntryByPathAsyncOnUIThread(
                           search_file_path,
                           callback);
     return;
-  } else if (root_->NeedsRefresh()) {
-    // If content is stale or from disk from cache, fetch content from
-    // the server.
-    ContentOrigin initial_origin = root_->origin();
-    root_->set_origin(REFRESHING);
-    ReloadFeedFromServerIfNeeded(initial_origin,
-                                 root_->largest_changestamp(),
-                                 search_file_path,
-                                 callback);
-    return;
   }
 
   // Post a task to the same thread, rather than calling it here, as