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      1 // Copyright 2014 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_ENGINE_DIRECTORY_UPDATE_HANDLER_H_
      6 #define SYNC_ENGINE_DIRECTORY_UPDATE_HANDLER_H_
      7 
      8 #include <map>
      9 
     10 #include "base/basictypes.h"
     11 #include "base/memory/ref_counted.h"
     12 #include "base/memory/scoped_ptr.h"
     13 #include "sync/base/sync_export.h"
     14 #include "sync/engine/process_updates_util.h"
     15 #include "sync/engine/update_handler.h"
     16 #include "sync/internal_api/public/base/model_type.h"
     17 #include "sync/internal_api/public/util/syncer_error.h"
     18 
     19 namespace sync_pb {
     20 class DataTypeProgressMarker;
     21 class GarbageCollectionDirective;
     22 class GetUpdatesResponse;
     23 }
     24 
     25 namespace syncer {
     26 
     27 namespace sessions {
     28 class StatusController;
     29 }
     30 
     31 namespace syncable {
     32 class Directory;
     33 }
     34 
     35 class DirectoryTypeDebugInfoEmitter;
     36 class ModelSafeWorker;
     37 
     38 // This class represents the syncable::Directory's processes for requesting and
     39 // processing updates from the sync server.
     40 //
     41 // Each instance of this class represents a particular type in the
     42 // syncable::Directory.  It can store and retreive that type's progress markers.
     43 // It can also process a set of received SyncEntities and store their data.
     44 class SYNC_EXPORT_PRIVATE DirectoryUpdateHandler : public UpdateHandler {
     45  public:
     46   DirectoryUpdateHandler(syncable::Directory* dir,
     47                          ModelType type,
     48                          scoped_refptr<ModelSafeWorker> worker,
     49                          DirectoryTypeDebugInfoEmitter* debug_info_emitter);
     50   virtual ~DirectoryUpdateHandler();
     51 
     52   // UpdateHandler implementation.
     53   virtual void GetDownloadProgress(
     54       sync_pb::DataTypeProgressMarker* progress_marker) const OVERRIDE;
     55   virtual void GetDataTypeContext(sync_pb::DataTypeContext* context) const
     56       OVERRIDE;
     57   virtual SyncerError ProcessGetUpdatesResponse(
     58       const sync_pb::DataTypeProgressMarker& progress_marker,
     59       const sync_pb::DataTypeContext& mutated_context,
     60       const SyncEntityList& applicable_updates,
     61       sessions::StatusController* status) OVERRIDE;
     62   virtual void ApplyUpdates(sessions::StatusController* status) OVERRIDE;
     63   virtual void PassiveApplyUpdates(sessions::StatusController* status) OVERRIDE;
     64 
     65  private:
     66   friend class DirectoryUpdateHandlerApplyUpdateTest;
     67   friend class DirectoryUpdateHandlerProcessUpdateTest;
     68 
     69   // Sometimes there is nothing to do, so we can return without doing anything.
     70   bool IsApplyUpdatesRequired();
     71 
     72   // Processes the given SyncEntities and stores their data in the directory.
     73   // Their types must match this update handler's type.
     74   void UpdateSyncEntities(
     75       syncable::ModelNeutralWriteTransaction* trans,
     76       const SyncEntityList& applicable_updates,
     77       sessions::StatusController* status);
     78 
     79   // Expires entries according to GC directives.
     80   void ExpireEntriesIfNeeded(
     81       syncable::ModelNeutralWriteTransaction* trans,
     82       const sync_pb::DataTypeProgressMarker& progress_marker);
     83 
     84   // Stores the given progress marker in the directory.
     85   // Its type must match this update handler's type.
     86   void UpdateProgressMarker(
     87       const sync_pb::DataTypeProgressMarker& progress_marker);
     88 
     89   bool IsValidProgressMarker(
     90       const sync_pb::DataTypeProgressMarker& progress_marker) const;
     91 
     92   // Skips all checks and goes straight to applying the updates.
     93   SyncerError ApplyUpdatesImpl(sessions::StatusController* status);
     94 
     95   syncable::Directory* dir_;
     96   ModelType type_;
     97   scoped_refptr<ModelSafeWorker> worker_;
     98   DirectoryTypeDebugInfoEmitter* debug_info_emitter_;
     99 
    100   scoped_ptr<sync_pb::GarbageCollectionDirective> cached_gc_directive_;
    101 
    102   DISALLOW_COPY_AND_ASSIGN(DirectoryUpdateHandler);
    103 };
    104 
    105 }  // namespace syncer
    106 
    107 #endif  // SYNC_ENGINE_DIRECTORY_UPDATE_HANDLER_H_
    108