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_BACKEND_MIGRATOR_H_
6#define CHROME_BROWSER_SYNC_BACKEND_MIGRATOR_H_
7
8#include "base/compiler_specific.h"
9#include "base/memory/weak_ptr.h"
10#include "base/observer_list.h"
11#include "components/sync_driver/data_type_manager.h"
12#include "content/public/browser/notification_observer.h"
13#include "content/public/browser/notification_registrar.h"
14#include "sync/internal_api/public/base/model_type.h"
15
16class ProfileSyncService;
17
18namespace syncer {
19struct UserShare;
20}  // namespace syncer
21
22namespace browser_sync {
23
24// Interface for anything that wants to know when the migrator's state
25// changes.
26class MigrationObserver {
27 public:
28  virtual void OnMigrationStateChange() = 0;
29
30 protected:
31  virtual ~MigrationObserver();
32};
33
34// A class to perform migration of a datatype pursuant to the 'MIGRATION_DONE'
35// code in the sync protocol definition (protocol/sync.proto).
36class BackendMigrator {
37 public:
38  enum State {
39    IDLE,
40    WAITING_TO_START,   // Waiting for previous configuration to finish.
41    DISABLING_TYPES,    // Exit criteria: SYNC_CONFIGURE_DONE for
42                        // enabled types _excluding_ |to_migrate_| and
43                        // empty download progress markers for types
44                        // in |to_migrate_|.
45    REENABLING_TYPES,   // Exit criteria: SYNC_CONFIGURE_DONE for enabled
46                        // types.
47  };
48
49  // TODO(akalin): Remove the dependency on |user_share|.
50  BackendMigrator(const std::string& name,
51                  syncer::UserShare* user_share,
52                  ProfileSyncService* service,
53                  sync_driver::DataTypeManager* manager,
54                  const base::Closure &migration_done_callback);
55  virtual ~BackendMigrator();
56
57  // Starts a sequence of events that will disable and reenable |types|.
58  void MigrateTypes(syncer::ModelTypeSet types);
59
60  void AddMigrationObserver(MigrationObserver* observer);
61  bool HasMigrationObserver(MigrationObserver* observer) const;
62  void RemoveMigrationObserver(MigrationObserver* observer);
63
64  State state() const;
65
66  // Called from ProfileSyncService to notify us of configure done.
67  // Note: We receive these notificiations only when our state is not IDLE.
68  void OnConfigureDone(
69      const sync_driver::DataTypeManager::ConfigureResult& result);
70
71  // Returns the types that are currently pending migration (if any).
72  syncer::ModelTypeSet GetPendingMigrationTypesForTest() const;
73
74 private:
75  void ChangeState(State new_state);
76
77  // Must be called only in state WAITING_TO_START.  If ready to
78  // start, meaning the data type manager is configured, calls
79  // RestartMigration() and returns true.  Otherwise, does nothing and
80  // returns false.
81  bool TryStart();
82
83  // Restarts migration, interrupting any existing migration.
84  void RestartMigration();
85
86  // Called by OnConfigureDone().
87  void OnConfigureDoneImpl(
88      const sync_driver::DataTypeManager::ConfigureResult& result);
89
90  const std::string name_;
91  syncer::UserShare* user_share_;
92  ProfileSyncService* service_;
93  sync_driver::DataTypeManager* manager_;
94
95  State state_;
96
97  ObserverList<MigrationObserver> migration_observers_;
98
99  syncer::ModelTypeSet to_migrate_;
100
101  base::Closure migration_done_callback_;
102
103  base::WeakPtrFactory<BackendMigrator> weak_ptr_factory_;
104
105  DISALLOW_COPY_AND_ASSIGN(BackendMigrator);
106};
107
108}  // namespace browser_sync
109
110#endif  // CHROME_BROWSER_SYNC_BACKEND_MIGRATOR_H_
111