sync/api/attachments/attachment_store_backend.h

   1 // Copyright 2015 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_ATTACHMENTS_ATTACHMENT_STORE_BACKEND_H_
   6 #define SYNC_API_ATTACHMENTS_ATTACHMENT_STORE_BACKEND_H_
   7
   8 #include "base/callback.h"
   9 #include "base/memory/ref_counted.h"
  10 #include "sync/api/attachments/attachment.h"
  11 #include "sync/api/attachments/attachment_id.h"
  12 #include "sync/api/attachments/attachment_store.h"
  13 #include "sync/base/sync_export.h"
  14
  15 namespace base {
  16 class SequencedTaskRunner;
  17 }  // namespace base
  18
  19 namespace syncer {
  20
  21 // Interface for AttachmentStore backends.
  22 //
  23 // AttachmentStoreBackend provides interface for different backends (on-disk,
  24 // in-memory). Factory methods in AttachmentStore create corresponding backend
  25 // and pass reference to AttachmentStore.
  26 // All functions in AttachmentStoreBackend mirror corresponding functions in
  27 // AttachmentStore.
  28 // All callbacks and result codes are used directly from AttachmentStore.
  29 // AttachmentStoreFrontend only passes callbacks and results without modifying
  30 // them, there is no need to declare separate set.
  31 class SYNC_EXPORT AttachmentStoreBackend {
  32  public:
  33   explicit AttachmentStoreBackend(
  34       const scoped_refptr<base::SequencedTaskRunner>& callback_task_runner);
  35   virtual ~AttachmentStoreBackend();
  36   virtual void Init(const AttachmentStore::InitCallback& callback) = 0;
  37   virtual void Read(AttachmentStore::Component component,
  38                     const AttachmentIdList& ids,
  39                     const AttachmentStore::ReadCallback& callback) = 0;
  40   virtual void Write(AttachmentStore::Component component,
  41                      const AttachmentList& attachments,
  42                      const AttachmentStore::WriteCallback& callback) = 0;
  43   virtual void SetReference(AttachmentStore::Component component,
  44                             const AttachmentIdList& ids) = 0;
  45   virtual void DropReference(AttachmentStore::Component component,
  46                              const AttachmentIdList& ids,
  47                              const AttachmentStore::DropCallback& callback) = 0;
  48   virtual void ReadMetadataById(
  49       AttachmentStore::Component component,
  50       const AttachmentIdList& ids,
  51       const AttachmentStore::ReadMetadataCallback& callback) = 0;
  52   virtual void ReadMetadata(
  53       AttachmentStore::Component component,
  54       const AttachmentStore::ReadMetadataCallback& callback) = 0;
  55
  56  protected:
  57   // Helper function to post callback on callback_task_runner.
  58   void PostCallback(const base::Closure& callback);
  59
  60  private:
  61   scoped_refptr<base::SequencedTaskRunner> callback_task_runner_;
  62
  63   DISALLOW_COPY_AND_ASSIGN(AttachmentStoreBackend);
  64 };
  65
  66 }  // namespace syncer
  67
  68 #endif  // SYNC_API_ATTACHMENTS_ATTACHMENT_STORE_BACKEND_H_