Drive: Removes unused cache files after the initial feed fetch.

chrome/browser/chromeos/gdata/stale_cache_files_remover.h

+// 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.
+
+#ifndef CHROME_BROWSER_CHROMEOS_GDATA_STALE_CACHE_FILE_REMOVER_H_
+#define CHROME_BROWSER_CHROMEOS_GDATA_STALE_CACHE_FILE_REMOVER_H_
+
+#include <string>
+#include <vector>
+
+#include "base/basictypes.h"
+#include "chrome/browser/chromeos/gdata/drive_file_system_interface.h"
+
+namespace gdata{
+
+class DriveCache;
+class DriveFileSystem;
+
+// This class removes stale cache files, which are present locally, but no
+// longer present on the server. This can happen if files are removed from the
+// server from other devices, or from the web interface.
+class StaleCacheFilesRemover : public DriveFileSystemInterface::Observer {
+ public:
+  StaleCacheFilesRemover(DriveFileSystemInterface* file_system,
+                         DriveCache* cache);
+  virtual ~StaleCacheFilesRemover();
+
+ private:
+  // Removes stale cache files.
+  // Gets the list of all the resource id and calls OnGetResourceIdsOfAllFiles()
+  // with the list.
+  virtual void OnInitialLoadFinished() OVERRIDE;
+
+  // Gets the cache entry of each resource id. And passes the cache entry to
+  // GetEntryInfoAndRemoveCacheIfNecessary().
+  void OnGetResourceIdsOfAllFiles(const std::vector<std::string>& resource_ids);
+
+  // Gets the file entry and calls RemoveCacheIfNecessary() with the file entry.
+  // This is called from StaleCacheFilesRemover::OnGetResourceIdsOfAllFiles().
+  void GetEntryInfoAndRemoveCacheIfNecessary(
+      const std::string& resource_id,
+      bool success,
+      const gdata::DriveCacheEntry& cache_entry);
+
+  // Check the cache file and removes if it is unavailable or invalid (eg. md5
+  // mismatch). This is called from GetCacheEntryAndRemoveCacheIfNecessary();
+  void RemoveCacheIfNecessary(
+      const std::string& resource_id,
+      const std::string& cache_md5,
+      DriveFileError error,
+      const FilePath& gdata_file_path,
+      scoped_ptr<gdata::DriveEntryProto> entry_proto);
+
+  DriveCache* cache_;  // Not owned.
+  DriveFileSystemInterface* file_system_;  // Not owned.
+
+  // Note: This should remain the last member so it'll be destroyed and
+  // invalidate its weak pointers before any other members are destroyed.
+  base::WeakPtrFactory<StaleCacheFilesRemover> weak_ptr_factory_;
+  DISALLOW_COPY_AND_ASSIGN(StaleCacheFilesRemover);
+};
+
+}  // namespace gdata
+
+#endif  // CHROME_BROWSER_CHROMEOS_GDATA_STALE_CACHE_FILE_REMOVER_H_