sync/internal_api/sync_context_proxy_impl.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 SYNC_INTERNAL_API_SYNC_CONTEXT_PROXY_IMPL_H_
   6 #define SYNC_INTERNAL_API_SYNC_CONTEXT_PROXY_IMPL_H_
   7
   8 #include "base/memory/scoped_ptr.h"
   9 #include "base/memory/weak_ptr.h"
  10 #include "base/sequenced_task_runner.h"
  11 #include "sync/base/sync_export.h"
  12 #include "sync/internal_api/public/base/model_type.h"
  13 #include "sync/internal_api/public/sync_context_proxy.h"
  14
  15 namespace syncer_v2 {
  16 class ModelTypeProcessor;
  17 class SyncContext;
  18 struct DataTypeState;
  19
  20 // Encapsulates a reference to the sync context and the thread it's running on.
  21 // Used by sync's data types to connect with the sync context.
  22 //
  23 // It is expected that this object will be copied to and used on many different
  24 // threads.  It is small and safe to pass by value.
  25 class SYNC_EXPORT_PRIVATE SyncContextProxyImpl : public SyncContextProxy {
  26  public:
  27   SyncContextProxyImpl(
  28       const scoped_refptr<base::SequencedTaskRunner>& sync_task_runner,
  29       const base::WeakPtr<SyncContext>& sync_context);
  30   ~SyncContextProxyImpl() override;
  31
  32   // Attempts to connect a non-blocking type to the sync context.
  33   //
  34   // This may fail under some unusual circumstances, like shutdown.  Due to the
  35   // nature of WeakPtrs and cross-thread communication, the caller will be
  36   // unable to distinguish a slow success from failure.
  37   //
  38   // Must be called from the thread where the data type lives.
  39   void ConnectTypeToSync(
  40       syncer::ModelType type,
  41       const DataTypeState& data_type_state,
  42       const UpdateResponseDataList& pending_updates,
  43       const base::WeakPtr<ModelTypeProcessor>& type_processor) override;
  44
  45   // Disables syncing for the given type on the sync thread.
  46   void Disconnect(syncer::ModelType type) override;
  47
  48   scoped_ptr<SyncContextProxy> Clone() const override;
  49
  50  private:
  51   // A SequencedTaskRunner representing the thread where the SyncContext lives.
  52   scoped_refptr<base::SequencedTaskRunner> sync_task_runner_;
  53
  54   // The SyncContext this object is wrapping.
  55   base::WeakPtr<SyncContext> sync_context_;
  56 };
  57
  58 }  // namespace syncer
  59
  60 #endif  // SYNC_INTERNAL_API_SYNC_CONTEXT_PROXY_IMPL_H_