components/sync_driver/generic_change_processor.h

   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 COMPONENTS_SYNC_DRIVER_GENERIC_CHANGE_PROCESSOR_H_
   6 #define COMPONENTS_SYNC_DRIVER_GENERIC_CHANGE_PROCESSOR_H_
   7
   8 #include <vector>
   9
  10 #include "base/compiler_specific.h"
  11 #include "base/memory/weak_ptr.h"
  12 #include "base/threading/non_thread_safe.h"
  13 #include "components/sync_driver/change_processor.h"
  14 #include "components/sync_driver/data_type_controller.h"
  15 #include "components/sync_driver/data_type_error_handler.h"
  16 #include "sync/api/attachments/attachment_store.h"
  17 #include "sync/api/sync_change_processor.h"
  18 #include "sync/api/sync_merge_result.h"
  19 #include "sync/internal_api/public/attachments/attachment_service.h"
  20 #include "sync/internal_api/public/attachments/attachment_service_proxy.h"
  21
  22 namespace syncer {
  23 class SyncData;
  24 class SyncableService;
  25 class WriteNode;
  26 class WriteTransaction;
  27
  28 typedef std::vector<syncer::SyncData> SyncDataList;
  29 }  // namespace syncer
  30
  31 namespace sync_driver {
  32 class SyncApiComponentFactory;
  33
  34 // Datatype agnostic change processor. One instance of GenericChangeProcessor
  35 // is created for each datatype and lives on the datatype's thread. It then
  36 // handles all interaction with the sync api, both translating pushes from the
  37 // local service into transactions and receiving changes from the sync model,
  38 // which then get converted into SyncChange's and sent to the local service.
  39 //
  40 // As a rule, the GenericChangeProcessor is not thread safe, and should only
  41 // be used on the same thread in which it was created.
  42 class GenericChangeProcessor : public ChangeProcessor,
  43                                public syncer::SyncChangeProcessor,
  44                                public syncer::AttachmentService::Delegate,
  45                                public base::NonThreadSafe {
  46  public:
  47   // Create a change processor for |type| and connect it to the syncer.
  48   // |attachment_store| can be NULL which means that datatype will not use sync
  49   // attachments.
  50   GenericChangeProcessor(
  51       syncer::ModelType type,
  52       DataTypeErrorHandler* error_handler,
  53       const base::WeakPtr<syncer::SyncableService>& local_service,
  54       const base::WeakPtr<syncer::SyncMergeResult>& merge_result,
  55       syncer::UserShare* user_share,
  56       SyncApiComponentFactory* sync_factory,
  57       const scoped_refptr<syncer::AttachmentStore>& attachment_store);
  58   ~GenericChangeProcessor() override;
  59
  60   // ChangeProcessor interface.
  61   // Build and store a list of all changes into |syncer_changes_|.
  62   void ApplyChangesFromSyncModel(
  63       const syncer::BaseTransaction* trans,
  64       int64 version,
  65       const syncer::ImmutableChangeRecordList& changes) override;
  66   // Passes |syncer_changes_|, built in ApplyChangesFromSyncModel, onto
  67   // |local_service_| by way of its ProcessSyncChanges method.
  68   void CommitChangesFromSyncModel() override;
  69
  70   // syncer::SyncChangeProcessor implementation.
  71   syncer::SyncError ProcessSyncChanges(
  72       const tracked_objects::Location& from_here,
  73       const syncer::SyncChangeList& change_list) override;
  74   syncer::SyncDataList GetAllSyncData(syncer::ModelType type) const override;
  75   syncer::SyncError UpdateDataTypeContext(
  76       syncer::ModelType type,
  77       syncer::SyncChangeProcessor::ContextRefreshStatus refresh_status,
  78       const std::string& context) override;
  79
  80   // syncer::AttachmentService::Delegate implementation.
  81   void OnAttachmentUploaded(const syncer::AttachmentId& attachment_id) override;
  82
  83   // Similar to above, but returns a SyncError for use by direct clients
  84   // of GenericChangeProcessor that may need more error visibility.
  85   virtual syncer::SyncError GetAllSyncDataReturnError(
  86       syncer::SyncDataList* data) const;
  87
  88   // If a datatype context associated with this GenericChangeProcessor's type
  89   // exists, fills |context| and returns true. Otheriwse, if there has not been
  90   // a context set, returns false.
  91   virtual bool GetDataTypeContext(std::string* context) const;
  92
  93   // Returns the number of items for this type.
  94   virtual int GetSyncCount();
  95
  96   // Generic versions of AssociatorInterface methods. Called by
  97   // syncer::SyncableServiceAdapter or the DataTypeController.
  98   virtual bool SyncModelHasUserCreatedNodes(bool* has_nodes);
  99   virtual bool CryptoReadyIfNecessary();
 100
 101   // Gets AttachmentService proxy for datatype.
 102   scoped_ptr<syncer::AttachmentService> GetAttachmentService() const;
 103
 104  protected:
 105   // ChangeProcessor interface.
 106   void StartImpl() override;  // Does nothing.
 107   syncer::UserShare* share_handle() const override;
 108
 109  private:
 110   // Logically part of ProcessSyncChanges.
 111   //
 112   // |new_attachments| is an output parameter containing newly added attachments
 113   // that need to be stored.  This method will append to it.
 114   syncer::SyncError HandleActionAdd(const syncer::SyncChange& change,
 115                                     const std::string& type_str,
 116                                     const syncer::WriteTransaction& trans,
 117                                     syncer::WriteNode* sync_node,
 118                                     syncer::AttachmentIdSet* new_attachments);
 119
 120   // Logically part of ProcessSyncChanges.
 121   //
 122   // |new_attachments| is an output parameter containing newly added attachments
 123   // that need to be stored.  This method will append to it.
 124   syncer::SyncError HandleActionUpdate(
 125       const syncer::SyncChange& change,
 126       const std::string& type_str,
 127       const syncer::WriteTransaction& trans,
 128       syncer::WriteNode* sync_node,
 129       syncer::AttachmentIdSet* new_attachments);
 130
 131   // Begin uploading attachments that have not yet been uploaded to the sync
 132   // server.
 133   void UploadAllAttachmentsNotOnServer();
 134
 135   const syncer::ModelType type_;
 136
 137   // The SyncableService this change processor will forward changes on to.
 138   const base::WeakPtr<syncer::SyncableService> local_service_;
 139
 140   // A SyncMergeResult used to track the changes made during association. The
 141   // owner will invalidate the weak pointer when association is complete. While
 142   // the pointer is valid though, we increment it with any changes received
 143   // via ProcessSyncChanges.
 144   const base::WeakPtr<syncer::SyncMergeResult> merge_result_;
 145
 146   // The current list of changes received from the syncer. We buffer because
 147   // we must ensure no syncapi transaction is held when we pass it on to
 148   // |local_service_|.
 149   // Set in ApplyChangesFromSyncModel, consumed in CommitChangesFromSyncModel.
 150   syncer::SyncChangeList syncer_changes_;
 151
 152   // Our handle to the sync model. Unlike normal ChangeProcessors, we need to
 153   // be able to access the sync model before the change processor begins
 154   // listening to changes (the local_service_ will be interacting with us
 155   // when it starts up). As such we can't wait until Start(_) has been called,
 156   // and have to keep a local pointer to the user_share.
 157   syncer::UserShare* const share_handle_;
 158
 159   // AttachmentService for datatype. Can be NULL if datatype doesn't use
 160   // attachments.
 161   scoped_ptr<syncer::AttachmentService> attachment_service_;
 162
 163   // Must be destroyed before attachment_service_ to ensure WeakPtrs are
 164   // invalidated before attachment_service_ is destroyed.
 165   // Can be NULL if attachment_service_ is NULL;
 166   scoped_ptr<base::WeakPtrFactory<syncer::AttachmentService> >
 167       attachment_service_weak_ptr_factory_;
 168   syncer::AttachmentServiceProxy attachment_service_proxy_;
 169   base::WeakPtrFactory<GenericChangeProcessor> weak_ptr_factory_;
 170
 171   DISALLOW_COPY_AND_ASSIGN(GenericChangeProcessor);
 172 };
 173
 174 }  // namespace sync_driver
 175
 176 #endif  // COMPONENTS_SYNC_DRIVER_GENERIC_CHANGE_PROCESSOR_H_