components/sync_driver/backend_migrator.h

   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 COMPONENTS_SYNC_DRIVER_BACKEND_MIGRATOR_H_
   6 #define COMPONENTS_SYNC_DRIVER_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 "sync/internal_api/public/base/model_type.h"
  13
  14 namespace syncer {
  15 struct UserShare;
  16 }  // namespace syncer
  17
  18 namespace sync_driver {
  19 class SyncService;
  20 }
  21
  22 namespace browser_sync {
  23
  24 // Interface for anything that wants to know when the migrator's state
  25 // changes.
  26 class 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).
  36 class 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                   sync_driver::SyncService* 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(const 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   sync_driver::SyncService* service_;
  93   sync_driver::DataTypeManager* manager_;
  94
  95   State state_;
  96
  97   base::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  // COMPONENTS_SYNC_DRIVER_BACKEND_MIGRATOR_H_