attachment_store.h revision 0529e5d033099cbfc42635f6f6183833b09dff6e
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_API_ATTACHMENTS_ATTACHMENT_STORE_H_ 6#define SYNC_API_ATTACHMENTS_ATTACHMENT_STORE_H_ 7 8#include "base/callback.h" 9#include "base/memory/ref_counted.h" 10#include "base/memory/scoped_ptr.h" 11#include "sync/api/attachments/attachment.h" 12#include "sync/api/attachments/attachment_id.h" 13#include "sync/base/sync_export.h" 14 15namespace base { 16class RefCountedMemory; 17} // namespace base 18 19namespace syncer { 20 21class Attachment; 22class AttachmentId; 23 24// A place to locally store and access Attachments. 25// 26// Destroying this object does not necessarily cancel outstanding async 27// operations. If you need cancel like semantics, use WeakPtr in the callbacks. 28class SYNC_EXPORT AttachmentStore { 29 public: 30 AttachmentStore(); 31 virtual ~AttachmentStore(); 32 33 // TODO(maniscalco): Consider udpating Read and Write methods to support 34 // resumable transfers (bug 353292). 35 36 enum Result { 37 SUCCESS, // No error, all completed successfully. 38 UNSPECIFIED_ERROR, // An unspecified error occurred for one or more items. 39 }; 40 41 typedef base::Callback<void(const Result&, scoped_ptr<AttachmentMap>)> 42 ReadCallback; 43 typedef base::Callback<void(const Result&)> WriteCallback; 44 typedef base::Callback<void(const Result&)> DropCallback; 45 46 // Asynchronously reads the attachments identified by |ids|. 47 // 48 // |callback| will be invoked when finished. If any of the attachments do not 49 // exist or could not be read, |callback|'s Result will be UNSPECIFIED_ERROR 50 // and |callback| may receive a partial result. That is, AttachmentMap may be 51 // empty or may contain the attachments that were read successfully. 52 // 53 // Reads on individual attachments are treated atomically; |callback| will not 54 // read only part of an attachment. 55 virtual void Read(const AttachmentIdList& ids, 56 const ReadCallback& callback) = 0; 57 58 // Asynchronously writes |attachments| to the store. 59 // 60 // Will not overwrite stored attachments. Attempting to overwrite an 61 // attachment that already exists is not an error. 62 // 63 // |callback| will be invoked when finished. If any of the attachments could 64 // not be written |callback|'s Result will be UNSPECIFIED_ERROR. When this 65 // happens, some or none of the attachments may have been written 66 // successfully. 67 virtual void Write(const AttachmentList& attachments, 68 const WriteCallback& callback) = 0; 69 70 // Asynchronously drops |attchments| from this store. 71 // 72 // This does not remove attachments from the server. 73 // 74 // |callback| will be invoked when finished. Attempting to drop an attachment 75 // that does not exist is not an error. If any of the existing attachment 76 // could not be dropped, |callback|'s Result will be UNSPECIFIED_ERROR. When 77 // this happens, some or none of the attachments may have been dropped 78 // successfully. 79 virtual void Drop(const AttachmentIdList& ids, 80 const DropCallback& callback) = 0; 81}; 82 83} // namespace syncer 84 85#endif // SYNC_API_ATTACHMENTS_ATTACHMENT_STORE_H_ 86