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 CHROME_UTILITY_MEDIA_GALLERIES_IPC_DATA_SOURCE_H_
6#define CHROME_UTILITY_MEDIA_GALLERIES_IPC_DATA_SOURCE_H_
7
8#include <map>
9#include <string>
10
11#include "base/memory/ref_counted.h"
12#include "base/threading/thread_checker.h"
13#include "chrome/utility/utility_message_handler.h"
14#include "media/base/data_source.h"
15
16namespace base {
17class TaskRunner;
18}
19
20namespace metadata {
21
22// Provides the metadata parser with bytes from the browser process via IPC.
23// Class must be created and destroyed on the utility thread. Class may be used
24// as a DataSource on a different thread. The utility thread must not be blocked
25// for read operations to succeed.
26class IPCDataSource: public media::DataSource,
27                     public UtilityMessageHandler {
28 public:
29  // May only be called on the utility thread.
30  explicit IPCDataSource(int64 total_size);
31  virtual ~IPCDataSource();
32
33  // Implementation of DataSource. These methods may be called on any single
34  // thread. First usage of these methods attaches a thread checker.
35  virtual void Stop() OVERRIDE;
36  virtual void Read(int64 position, int size, uint8* data,
37                    const ReadCB& read_cb) OVERRIDE;
38  virtual bool GetSize(int64* size_out) OVERRIDE;
39  virtual bool IsStreaming() OVERRIDE;
40  virtual void SetBitrate(int bitrate) OVERRIDE;
41
42  // Implementation of UtilityMessageHandler. May only be called on the utility
43  // thread.
44  virtual bool OnMessageReceived(const IPC::Message& message) OVERRIDE;
45
46 private:
47  struct Request {
48    Request();
49    ~Request();
50    uint8* destination;
51    ReadCB callback;
52  };
53
54  void ReadOnUtilityThread(int64 position, int size, uint8* data,
55                           const ReadCB& read_cb);
56
57  void OnRequestBlobBytesFinished(int64 request_id,
58                                  const std::string& bytes);
59
60  const int64 total_size_;
61
62  scoped_refptr<base::TaskRunner> utility_task_runner_;
63  std::map<int64, Request> pending_requests_;
64  int64 next_request_id_;
65
66  base::ThreadChecker utility_thread_checker_;
67
68  // Enforces that the DataSource methods are called on one other thread only.
69  base::ThreadChecker data_source_thread_checker_;
70};
71
72}  // namespace metadata
73
74#endif  // CHROME_UTILITY_MEDIA_GALLERIES_IPC_DATA_SOURCE_H_
75