remoting/protocol/monitored_video_stub.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 REMOTING_PROTOCOL_MONITORED_VIDEO_STUB_H_
   6 #define REMOTING_PROTOCOL_MONITORED_VIDEO_STUB_H_
   7
   8 #include "base/callback.h"
   9 #include "base/threading/thread_checker.h"
  10 #include "base/timer/timer.h"
  11 #include "remoting/protocol/video_stub.h"
  12
  13 namespace base {
  14 class ThreadChecker;
  15 } // namespace base
  16
  17 namespace remoting {
  18 namespace protocol {
  19
  20 // MonitoredVideoStub is responsible for notifying the event handler if no
  21 // frames have been received within |connectivity_check_delay|.
  22 // The implementation uses the decorator pattern in which the MonitoredVideoStub
  23 // implements the same interface as the VideoStub. It overrides the
  24 // ProcessVideoPacket function to provide notification to the client when the
  25 // video channel is connected and forward the packet to the underlying
  26 // VideoStub. Multiple decorators can be stacked on top of each other if more
  27 // functionality is needed in the future.
  28 class MonitoredVideoStub : public VideoStub {
  29  public:
  30   // Callback to be called when channel state changes.  The Callback should not
  31   // destroy the MonitoredVideoStub object.
  32   typedef base::Callback<void(bool connected)> ChannelStateCallback;
  33
  34   static const int kConnectivityCheckDelaySeconds = 2;
  35
  36   MonitoredVideoStub(
  37       VideoStub* video_stub,
  38       base::TimeDelta connectivity_check_delay,
  39       const ChannelStateCallback& callback);
  40   virtual ~MonitoredVideoStub();
  41
  42   // VideoStub implementation.
  43   virtual void ProcessVideoPacket(scoped_ptr<VideoPacket> packet,
  44                                   const base::Closure& done) OVERRIDE;
  45
  46  private:
  47   void OnConnectivityCheckTimeout();
  48   void NotifyChannelState(bool connected);
  49
  50   VideoStub* video_stub_;
  51   ChannelStateCallback callback_;
  52   base::ThreadChecker thread_checker_;
  53   bool is_connected_;
  54   base::DelayTimer<MonitoredVideoStub> connectivity_check_timer_;
  55
  56   DISALLOW_COPY_AND_ASSIGN(MonitoredVideoStub);
  57 };
  58
  59 }  // namespace protocol
  60 }  // namespace remoting
  61
  62 #endif  // REMOTING_PROTOCOL_MONITORED_VIDEO_STUB_H_