sync_change.h revision 5821806d5e7f356e8fa4b058a389a808ea183019 
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_API_SYNC_CHANGE_H_
6#define SYNC_API_SYNC_CHANGE_H_
7
8#include <iosfwd>
9#include <string>
10#include <vector>
11
12#include "base/location.h"
13#include "sync/api/sync_data.h"
14
15namespace syncer {
16
17// A SyncChange object reflects a change to a piece of synced data. The change
18// can be either a delete, add, or an update. All data relevant to the change
19// is encapsulated within the SyncChange, which, once created, is immutable.
20// Note: it is safe and cheap to pass these by value or make copies, as they do
21// not create deep copies of their internal data.
22class SyncChange {
23 public:
24  enum SyncChangeType {
25    ACTION_INVALID,
26    ACTION_ADD,
27    ACTION_UPDATE,
28    ACTION_DELETE
29  };
30
31  // Default constructor creates an invalid change.
32  SyncChange();
33  // Create a new change with the specified sync data.
34  SyncChange(
35      const tracked_objects::Location& from_here,
36      SyncChangeType change_type,
37      const SyncData& sync_data);
38  ~SyncChange();
39
40  // Copy constructor and assignment operator welcome.
41
42  // Whether this change is valid. This must be true before attempting to access
43  // the data.
44  // Deletes: Requires valid tag when going to the syncer. Requires valid
45  //          specifics when coming from the syncer.
46  // Adds, Updates: Require valid tag and specifics when going to the syncer.
47  //                Require only valid specifics when coming from the syncer.
48  bool IsValid() const;
49
50  // Getters.
51  SyncChangeType change_type() const;
52  SyncData sync_data() const;
53  tracked_objects::Location location() const;
54
55  // Returns a string representation of |change_type|.
56  static std::string ChangeTypeToString(SyncChangeType change_type);
57
58  // Returns a string representation of the entire object. Used for gmock
59  // printing method, PrintTo.
60  std::string ToString() const;
61
62 private:
63  tracked_objects::Location location_;
64
65  SyncChangeType change_type_;
66
67  // An immutable container for the data of this SyncChange. Whenever
68  // SyncChanges are copied, they copy references to this data.
69  SyncData sync_data_;
70};
71
72// gmock printer helper.
73void PrintTo(const SyncChange& sync_change, std::ostream* os);
74
75}  // namespace syncer
76
77#endif  // SYNC_API_SYNC_CHANGE_H_
78