remote_change_processor.h revision 868fa2fe829687343ffae624259930155e16dbd8 
1// Copyright (c) 2012 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#ifndef CHROME_BROWSER_SYNC_FILE_SYSTEM_REMOTE_CHANGE_PROCESSOR_H_
6#define CHROME_BROWSER_SYNC_FILE_SYSTEM_REMOTE_CHANGE_PROCESSOR_H_
7
8#include "base/basictypes.h"
9#include "base/callback_forward.h"
10#include "webkit/browser/fileapi/syncable/sync_callbacks.h"
11#include "webkit/browser/fileapi/syncable/sync_status_code.h"
12
13namespace base {
14class FilePath;
15}
16
17namespace fileapi {
18class FileSystemURL;
19}
20
21namespace sync_file_system {
22
23class FileChange;
24class FileChangeList;
25class SyncFileMetadata;
26
27// Represents an interface to process one remote change and applies
28// it to the local file system.
29// This interface is to be implemented/backed by LocalSyncFileService.
30class RemoteChangeProcessor {
31 public:
32  // Callback type for PrepareForProcessRemoteChange.
33  // |file_type| indicates the current file/directory type of the target
34  // URL in the local filesystem. If the target URL does not exist it is
35  // set to SYNC_FILE_TYPE_UNKNOWN.
36  // |changes| indicates a set of pending changes for the target URL.
37  typedef base::Callback<void(
38      SyncStatusCode status,
39      const SyncFileMetadata& metadata,
40      const FileChangeList& changes)> PrepareChangeCallback;
41
42  RemoteChangeProcessor() {}
43  virtual ~RemoteChangeProcessor() {}
44
45  // This must be called before processing the change for the |url|.
46  // This tries to lock the target |url| and returns the local changes
47  // if any. (The change returned by the callback is to make a decision
48  // on conflict resolution, but NOT for applying local changes to the remote,
49  // which is supposed to be done by LocalChangeProcessor)
50  virtual void PrepareForProcessRemoteChange(
51      const fileapi::FileSystemURL& url,
52      const PrepareChangeCallback& callback) = 0;
53
54  // This is called to apply the remote |change|. If the change type is
55  // ADD_OR_UPDATE for a file, |local_path| needs to point to a
56  // local file path that contains the latest file image (e.g. a path
57  // to a temporary file which has the data downloaded from the server).
58  // This may fail with an error but should NOT result in a conflict
59  // (as we must have checked the change status in PrepareRemoteSync and
60  // have disabled any further writing).
61  virtual void ApplyRemoteChange(
62      const FileChange& change,
63      const base::FilePath& local_path,
64      const fileapi::FileSystemURL& url,
65      const SyncStatusCallback& callback) = 0;
66
67  // Clears all local changes. This should be called when the remote sync
68  // service reconciled or processed the existing local changes while
69  // processing a remote change.
70  virtual void ClearLocalChanges(
71      const fileapi::FileSystemURL& url,
72      const base::Closure& completion_callback) = 0;
73
74  // Records a fake local change so that the change will be processed in the
75  // next local sync.
76  // This is called when the remote side wants to trigger a local sync
77  // to propagate the local change to the remote change (e.g. to
78  // resolve a conflict by uploading the local file).
79  virtual void RecordFakeLocalChange(
80      const fileapi::FileSystemURL& url,
81      const FileChange& change,
82      const SyncStatusCallback& callback) = 0;
83
84 private:
85  DISALLOW_COPY_AND_ASSIGN(RemoteChangeProcessor);
86};
87
88}  // namespace sync_file_system
89
90#endif  // CHROME_BROWSER_SYNC_FILE_SYSTEM_REMOTE_CHANGE_PROCESSOR_H_
91