sync/api/syncable_service.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_SYNCABLE_SERVICE_H_
   6 #define SYNC_API_SYNCABLE_SERVICE_H_
   7
   8 #include <vector>
   9
  10 #include "base/callback.h"
  11 #include "base/compiler_specific.h"
  12 #include "base/memory/scoped_ptr.h"
  13 #include "base/memory/weak_ptr.h"
  14 #include "sync/api/attachments/attachment_store.h"
  15 #include "sync/api/sync_change_processor.h"
  16 #include "sync/api/sync_data.h"
  17 #include "sync/api/sync_error.h"
  18 #include "sync/api/sync_merge_result.h"
  19 #include "sync/base/sync_export.h"
  20 #include "sync/internal_api/public/base/model_type.h"
  21
  22 namespace syncer {
  23
  24 class SyncErrorFactory;
  25
  26 // TODO(zea): remove SupportsWeakPtr in favor of having all SyncableService
  27 // implementers provide a way of getting a weak pointer to themselves.
  28 // See crbug.com/100114.
  29 class SYNC_EXPORT SyncableService
  30     : public SyncChangeProcessor,
  31       public base::SupportsWeakPtr<SyncableService> {
  32  public:
  33   // A StartSyncFlare is useful when your SyncableService has a need for sync
  34   // to start ASAP, typically because a local change event has occurred but
  35   // MergeDataAndStartSyncing hasn't been called yet, meaning you don't have a
  36   // SyncChangeProcessor. The sync subsystem will respond soon after invoking
  37   // Run() on your flare by calling MergeDataAndStartSyncing. The ModelType
  38   // parameter is included so that the recieving end can track usage and timing
  39   // statistics, make optimizations or tradeoffs by type, etc.
  40   typedef base::Callback<void(ModelType)> StartSyncFlare;
  41
  42   // Informs the service to begin syncing the specified synced datatype |type|.
  43   // The service should then merge |initial_sync_data| into it's local data,
  44   // calling |sync_processor|'s ProcessSyncChanges as necessary to reconcile the
  45   // two. After this, the SyncableService's local data should match the server
  46   // data, and the service should be ready to receive and process any further
  47   // SyncChange's as they occur.
  48   // Returns: a SyncMergeResult whose error field reflects whether an error
  49   //          was encountered while merging the two models. The merge result
  50   //          may also contain optional merge statistics.
  51   virtual SyncMergeResult MergeDataAndStartSyncing(
  52       ModelType type,
  53       const SyncDataList& initial_sync_data,
  54       scoped_ptr<SyncChangeProcessor> sync_processor,
  55       scoped_ptr<SyncErrorFactory> error_handler) = 0;
  56
  57   // Stop syncing the specified type and reset state.
  58   virtual void StopSyncing(ModelType type) = 0;
  59
  60   // SyncChangeProcessor interface.
  61   // Process a list of new SyncChanges and update the local data as necessary.
  62   // Returns: A default SyncError (IsSet() == false) if no errors were
  63   //          encountered, and a filled SyncError (IsSet() == true)
  64   //          otherwise.
  65   virtual SyncError ProcessSyncChanges(
  66       const tracked_objects::Location& from_here,
  67       const SyncChangeList& change_list) override = 0;
  68
  69   // Returns AttachmentStore used by datatype. Attachment store is used by sync
  70   // when uploading or downloading attachments.
  71   // GetAttachmentStore is called right before MergeDataAndStartSyncing. If at
  72   // that time GetAttachmentStore returns NULL then datatype is considered not
  73   // using attachments and all attempts to upload/download attachments will
  74   // fail. Default implementation returns NULL. Datatype that uses sync
  75   // attachemnts should create attachment store and implement GetAttachmentStore
  76   // to return pointer to it.
  77   virtual scoped_refptr<AttachmentStore> GetAttachmentStore();
  78
  79  protected:
  80   ~SyncableService() override;
  81 };
  82
  83 }  // namespace syncer
  84
  85 #endif  // SYNC_API_SYNCABLE_SERVICE_H_