sync/api/sync_change.h

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