OLD | NEW |
| (Empty) |
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 SYNC_ENGINE_CLEANUP_DISABLED_TYPES_COMMAND_H_ | |
6 #define SYNC_ENGINE_CLEANUP_DISABLED_TYPES_COMMAND_H_ | |
7 | |
8 #include "base/compiler_specific.h" | |
9 #include "sync/engine/syncer_command.h" | |
10 | |
11 namespace syncer { | |
12 | |
13 // A syncer command that purges (from memory and disk) entries belonging to | |
14 // a ModelType or ServerModelType that the user has not elected to sync. | |
15 // | |
16 // This is done as part of a session to 1) ensure it does not block the UI, | |
17 // and 2) avoid complicated races that could arise between a) deleting | |
18 // things b) a sync session trying to use these things c) and the potential | |
19 // re-enabling of the data type by the user before some scheduled deletion | |
20 // took place. Here, we are safe to perform I/O synchronously and we know it | |
21 // is a safe time to delete as we are in the only active session. | |
22 // | |
23 // The removal from memory is done synchronously, while the disk purge is left | |
24 // to an asynchronous SaveChanges operation. However, all the updates for | |
25 // meta data fields (such as initial_sync_ended) as well as the actual entry | |
26 // deletions will be committed in a single sqlite transaction. Thus it is | |
27 // possible that disabled types re-appear (in the sync db) after a reboot, | |
28 // but things will remain in a consistent state. This kind of error case is | |
29 // cared for in this command by retrying; see ExecuteImpl. | |
30 class CleanupDisabledTypesCommand : public SyncerCommand { | |
31 public: | |
32 CleanupDisabledTypesCommand(); | |
33 virtual ~CleanupDisabledTypesCommand(); | |
34 | |
35 // SyncerCommand implementation. | |
36 virtual SyncerError ExecuteImpl(sessions::SyncSession* session) OVERRIDE; | |
37 | |
38 private: | |
39 DISALLOW_COPY_AND_ASSIGN(CleanupDisabledTypesCommand); | |
40 }; | |
41 | |
42 } // namespace syncer | |
43 | |
44 #endif // SYNC_ENGINE_CLEANUP_DISABLED_TYPES_COMMAND_H_ | |
OLD | NEW |