Add SNAPSHOT sync mode to LocalFileSyncContext::PrepareForSync

chrome/browser/sync_file_system/local/local_file_sync_context.h

 // Copyright 2013 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.
 
 #ifndef CHROME_BROWSER_SYNC_FILE_SYSTEM_LOCAL_LOCAL_FILE_SYNC_CONTEXT_H_
 #define CHROME_BROWSER_SYNC_FILE_SYSTEM_LOCAL_LOCAL_FILE_SYNC_CONTEXT_H_
 
 #include <deque>
 #include <map>
 #include <set>
@@ skipping 32 matching lines @@
 
 // This class works as a bridge between LocalFileSyncService (which is a
 // per-profile object) and FileSystemContext's (which is a per-storage-partition
 // object and may exist multiple in a profile).
 // An instance of this class is shared by FileSystemContexts and outlives
 // LocalFileSyncService.
 class LocalFileSyncContext
     : public base::RefCountedThreadSafe<LocalFileSyncContext>,
       public LocalFileSyncStatus::Observer {
  public:
+  enum SyncMode {
+    SYNC_EXCLUSIVE,
+    SYNC_SNAPSHOT,
+  };
+
   typedef base::Callback<void(
       SyncStatusCode status, const LocalFileSyncInfo& sync_file_info)>
           LocalFileSyncInfoCallback;
 
   typedef base::Callback<void(SyncStatusCode status,
                               bool has_pending_changes)>
       HasPendingLocalChangeCallback;
 
   LocalFileSyncContext(base::SingleThreadTaskRunner* ui_task_runner,
                        base::SingleThreadTaskRunner* io_task_runner);
@@ skipping 17 matching lines @@
   void GetFileForLocalSync(fileapi::FileSystemContext* file_system_context,
                            const LocalFileSyncInfoCallback& callback);
 
   // Clears all pending local changes for |url|. |done_callback| is called
   // when the changes are cleared.
   // This method must be called on UI thread.
   void ClearChangesForURL(fileapi::FileSystemContext* file_system_context,
                           const fileapi::FileSystemURL& url,
                           const base::Closure& done_callback);
 
+  // Updates the on-disk dirty flag for |url| in the tracker DB.
+  // This will clear the dirty flag if |sync_finish_status| is SYNC_STATUS_OK
+  // or SYNC_STATUS_HAS_CONFLICT.
+  // |done_callback| is called when the changes are committed.
+  void CommitChangeStatusForURL(
+      fileapi::FileSystemContext* file_system_context,
+      const fileapi::FileSystemURL& url,
+      SyncStatusCode sync_finish_status,
+      const base::Closure& done_callback);
+
   // A local or remote sync has been finished (either successfully or
   // with an error). Clears the internal sync flag and enable writing for |url|.
   // This method must be called on UI thread.
   void ClearSyncFlagForURL(const fileapi::FileSystemURL& url);
 
   // Prepares for sync |url| by disabling writes on |url|.
   // If the target |url| is being written and cannot start sync it
   // returns SYNC_STATUS_WRITING status code via |callback|.
-  // Otherwise it disables writes, marks the |url| syncing and returns
-  // the current change set made on |url|.
+  // Otherwise returns the current change sets made on |url|.
+  //
+  // If |sync_mode| is SYNC_EXCLUSIVE this leaves the target file.
+  // If |sync_mode| is SYNC_SNAPSHOT this creates a snapshot (if the
+  // target file is not deleted) and unlocks the file before returning.
+  //
   // This method must be called on UI thread.
   void PrepareForSync(fileapi::FileSystemContext* file_system_context,
                       const fileapi::FileSystemURL& url,
+                      SyncMode sync_mode,
                       const LocalFileSyncInfoCallback& callback);
 
   // Registers |url| to wait until sync is enabled for |url|.
   // |on_syncable_callback| is to be called when |url| becomes syncable
   // (i.e. when we have no pending writes and the file is successfully locked
   // for sync).
   //
   // Calling this method again while this already has another URL waiting
   // for sync will overwrite the previously registered URL.
   //
@@ skipping 104 matching lines @@
       std::deque<fileapi::FileSystemURL>* remaining_urls,
       const LocalFileSyncInfoCallback& callback,
       SyncStatusCode status,
       const LocalFileSyncInfo& sync_file_info);
 
   // Callback routine for PrepareForSync and GetFileForLocalSync.
   void DidGetWritingStatusForSync(
       fileapi::FileSystemContext* file_system_context,
       SyncStatusCode status,
       const fileapi::FileSystemURL& url,
+      SyncMode sync_mode,
       const LocalFileSyncInfoCallback& callback);
 
   // Helper routine for ClearSyncFlagForURL.
-  void EnableWritingOnIOThread(const fileapi::FileSystemURL& url);
+  void EnableWritingOnIOThread(const fileapi::FileSystemURL& url,
+                               bool may_have_updates);
 
   void DidRemoveExistingEntryForApplyRemoteChange(
       fileapi::FileSystemContext* file_system_context,
       const FileChange& change,
       const base::FilePath& local_path,
       const fileapi::FileSystemURL& url,
       const SyncStatusCallback& callback,
       base::PlatformFileError error);
 
   // Callback routine for ApplyRemoteChange.
@@ skipping 51 matching lines @@
   ObserverList<LocalOriginChangeObserver> origin_change_observers_;
 
   int mock_notify_changes_duration_in_sec_;
 
   DISALLOW_COPY_AND_ASSIGN(LocalFileSyncContext);
 };
 
 }  // namespace sync_file_system
 
 #endif  // CHROME_BROWSER_SYNC_FILE_SYSTEM_LOCAL_LOCAL_FILE_SYNC_CONTEXT_H_