Cast:Transport: Dividing A/V Initialization pipeline

media/cast/audio_sender/audio_sender.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "media/cast/audio_sender/audio_sender.h"
 
 #include "base/bind.h"
 #include "base/logging.h"
 #include "base/message_loop/message_loop.h"
 #include "media/cast/audio_sender/audio_encoder.h"
@@ skipping 25 matching lines @@
 };
 
 class LocalRtpSenderStatistics : public RtpSenderStatistics {
  public:
   LocalRtpSenderStatistics(
       transport::CastTransportSender* const transport_sender,
       int frequency)
       : transport_sender_(transport_sender),
         frequency_(0),
         sender_info_(),
-        rtp_timestamp_(0) {
-    transport_sender_->SubscribeAudioRtpStatsCallback(base::Bind(
-        &LocalRtpSenderStatistics::StoreStatistics, base::Unretained(this)));
+        rtp_timestamp_(0),
+        weak_factory_(this) {
+    transport_sender_->SubscribeAudioRtpStatsCallback(
+        base::Bind(&LocalRtpSenderStatistics::StoreStatistics,
+                   weak_factory_.GetWeakPtr()));

[hubbe, 2014/02/21 23:41:23]

Here I can sort of understand the need for weak ptrs since this class doesn't
seem to own the transport, and thus cannot guarantee that the transport is
destroyed before this class.

   }
 
   virtual void GetStatistics(const base::TimeTicks& now,
                              transport::RtcpSenderInfo* sender_info) OVERRIDE {
     // Update and return last stored statistics.
     uint32 ntp_seconds = 0;
     uint32 ntp_fraction = 0;
     uint32 rtp_timestamp = 0;
     if (rtp_timestamp_ > 0) {
       base::TimeDelta time_since_last_send = now - time_sent_;
@@ skipping 18 matching lines @@
     rtp_timestamp_ = rtp_timestamp;
   }
 
  private:
   transport::CastTransportSender* const transport_sender_;
   int frequency_;
   transport::RtcpSenderInfo sender_info_;
   base::TimeTicks time_sent_;
   uint32 rtp_timestamp_;
 
+  base::WeakPtrFactory<LocalRtpSenderStatistics> weak_factory_;
+
   DISALLOW_IMPLICIT_CONSTRUCTORS(LocalRtpSenderStatistics);
 };
 
 // TODO(mikhal): Reduce heap allocation when not needed.
 AudioSender::AudioSender(scoped_refptr<CastEnvironment> cast_environment,
                          const AudioSenderConfig& audio_config,
                          transport::CastTransportSender* const transport_sender)
     : cast_environment_(cast_environment),
       transport_sender_(transport_sender),
       rtcp_feedback_(new LocalRtcpAudioSenderFeedback(this)),
@@ skipping 106 matching lines @@
 }
 
 void AudioSender::ResendPacketsOnTransportThread(
     const transport::MissingFramesAndPacketsMap& missing_packets) {
   DCHECK(cast_environment_->CurrentlyOn(CastEnvironment::TRANSPORT));
   transport_sender_->ResendPackets(true, missing_packets);
 }
 
 }  // namespace cast
 }  // namespace media