1// Copyright 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_API_SYNC_CHANGE_PROCESSOR_H_
6#define SYNC_API_SYNC_CHANGE_PROCESSOR_H_
7
8#include <vector>
9
10#include "sync/api/sync_data.h"
11#include "sync/api/sync_error.h"
12#include "sync/base/sync_export.h"
13#include "sync/internal_api/public/base/model_type.h"
14
15namespace tracked_objects {
16class Location;
17}  // namespace tracked_objects
18
19namespace syncer {
20
21class SyncChange;
22
23typedef std::vector<SyncChange> SyncChangeList;
24
25// An interface for services that handle receiving SyncChanges.
26class SYNC_EXPORT SyncChangeProcessor {
27 public:
28  // Whether a context change should force a datatype refresh or not.
29  enum ContextRefreshStatus { NO_REFRESH, REFRESH_NEEDED };
30  typedef base::Callback<void(const SyncData&)> GetSyncDataCallback;
31
32  SyncChangeProcessor();
33  virtual ~SyncChangeProcessor();
34
35  // Process a list of SyncChanges.
36  // Returns: A default SyncError (IsSet() == false) if no errors were
37  //          encountered, and a filled SyncError (IsSet() == true)
38  //          otherwise.
39  // Inputs:
40  //   |from_here|: allows tracking of where sync changes originate.
41  //   |change_list|: is the list of sync changes in need of processing.
42  virtual SyncError ProcessSyncChanges(
43      const tracked_objects::Location& from_here,
44      const SyncChangeList& change_list) = 0;
45
46  // Fills a list of SyncData. This should create an up to date representation
47  // of all the data known to the ChangeProcessor for |datatype|, and
48  // should match/be a subset of the server's view of that datatype.
49  //
50  // WARNING: This can be a potentially slow & memory intensive operation and
51  // should only be used when absolutely necessary / sparingly.
52  virtual SyncDataList GetAllSyncData(ModelType type) const = 0;
53
54  // Retrieves the SyncData identified by |type| and |sync_tag| and invokes
55  // |callback| asynchronously. If no such SyncData exists locally, IsValid on
56  // the SyncData passed to |callback| will return false.
57  //
58  // This is an asynchronous local operation that may result in disk IO.
59  //
60  // Refer to sync_data.h for a description of |sync_tag|.
61  //
62  // TODO:(maniscalco): N.B. this method should really be pure virtual. An
63  // implentation is provided here just to verify that everything compiles.
64  // Update this method to be pure virtual (bug 353300).
65  virtual void GetSyncData(const ModelType& type,
66                           const std::string& sync_tag,
67                           const GetSyncDataCallback& callback) const {}
68
69  // Updates the context for |type|, triggering an optional context refresh.
70  // Default implementation does nothing. A type's context is a per-client blob
71  // that can affect all SyncData sent to/from the server, much like a cookie.
72  // TODO(zea): consider pulling the refresh logic into a separate method
73  // unrelated to datatype implementations.
74  virtual syncer::SyncError UpdateDataTypeContext(
75      ModelType type,
76      ContextRefreshStatus refresh_status,
77      const std::string& context);
78};
79
80}  // namespace syncer
81
82#endif  // SYNC_API_SYNC_CHANGE_PROCESSOR_H_
83