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