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 AttachmentService;
  25 class SyncErrorFactory;
  26
  27 // TODO(zea): remove SupportsWeakPtr in favor of having all SyncableService
  28 // implementers provide a way of getting a weak pointer to themselves.
  29 // See crbug.com/100114.
  30 class SYNC_EXPORT SyncableService
  31     : public SyncChangeProcessor,
  32       public base::SupportsWeakPtr<SyncableService> {
  33  public:
  34   // A StartSyncFlare is useful when your SyncableService has a need for sync
  35   // to start ASAP, typically because a local change event has occurred but
  36   // MergeDataAndStartSyncing hasn't been called yet, meaning you don't have a
  37   // SyncChangeProcessor. The sync subsystem will respond soon after invoking
  38   // Run() on your flare by calling MergeDataAndStartSyncing. The ModelType
  39   // parameter is included so that the recieving end can track usage and timing
  40   // statistics, make optimizations or tradeoffs by type, etc.
  41   typedef base::Callback<void(ModelType)> StartSyncFlare;
  42
  43   // Informs the service to begin syncing the specified synced datatype |type|.
  44   // The service should then merge |initial_sync_data| into it's local data,
  45   // calling |sync_processor|'s ProcessSyncChanges as necessary to reconcile the
  46   // two. After this, the SyncableService's local data should match the server
  47   // data, and the service should be ready to receive and process any further
  48   // SyncChange's as they occur.
  49   // Returns: a SyncMergeResult whose error field reflects whether an error
  50   //          was encountered while merging the two models. The merge result
  51   //          may also contain optional merge statistics.
  52   virtual SyncMergeResult MergeDataAndStartSyncing(
  53       ModelType type,
  54       const SyncDataList& initial_sync_data,
  55       scoped_ptr<SyncChangeProcessor> sync_processor,
  56       scoped_ptr<SyncErrorFactory> error_handler) = 0;
  57
  58   // Stop syncing the specified type and reset state.
  59   virtual void StopSyncing(ModelType type) = 0;
  60
  61   // SyncChangeProcessor interface.
  62   // Process a list of new SyncChanges and update the local data as necessary.
  63   // Returns: A default SyncError (IsSet() == false) if no errors were
  64   //          encountered, and a filled SyncError (IsSet() == true)
  65   //          otherwise.
  66   SyncError ProcessSyncChanges(const tracked_objects::Location& from_here,
  67                                const SyncChangeList& change_list) override = 0;
  68
  69   // Returns AttachmentStore for use by sync when uploading or downloading
  70   // attachments.
  71   // GetAttachmentStoreForSync is called right before MergeDataAndStartSyncing.
  72   // If at that time GetAttachmentStoreForSync returns NULL then datatype is
  73   // considered not using attachments and all attempts to upload/download
  74   // attachments will fail. Default implementation returns NULL. Datatype that
  75   // uses sync attachments should create attachment store, implement
  76   // GetAttachmentStoreForSync to return result of
  77   // AttachmentStore::CreateAttachmentStoreForSync() from attachment store
  78   // object.
  79   virtual scoped_ptr<AttachmentStoreForSync> GetAttachmentStoreForSync();
  80
  81   // Called by sync to provide AttachmentService to be used to download
  82   // attachments.
  83   // SetAttachmentService is called after GetAttachmentStore and right before
  84   // MergeDataAndStartSyncing and only if GetAttachmentStore has returned a
  85   // non-NULL store instance. Default implementation does nothing.
  86   // Datatype that uses attachments must take ownerhip of the provided
  87   // AttachmentService instance.
  88   virtual void SetAttachmentService(
  89       scoped_ptr<AttachmentService> attachment_service);
  90
  91  protected:
  92   ~SyncableService() override;
  93 };
  94
  95 }  // namespace syncer
  96
  97 #endif  // SYNC_API_SYNCABLE_SERVICE_H_