Cast: Implement priority packets in PacedSender

media/cast/net/pacing/paced_sender.h

 // Copyright 2014 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.
 
 #ifndef MEDIA_CAST_NET_PACING_PACED_SENDER_H_
 #define MEDIA_CAST_NET_PACING_PACED_SENDER_H_
 
-#include <list>
+#include <map>
 #include <vector>
 
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
 #include "base/single_thread_task_runner.h"
 #include "base/threading/non_thread_safe.h"
 #include "base/time/default_tick_clock.h"
 #include "base/time/tick_clock.h"
 #include "base/time/time.h"
@@ skipping 43 matching lines @@
       LoggingImpl* logging,
       PacketSender* external_transport,
       const scoped_refptr<base::SingleThreadTaskRunner>& transport_task_runner);
 
   virtual ~PacedSender();
 
   // These must be called before non-RTCP packets are sent.
   void RegisterAudioSsrc(uint32 audio_ssrc);
   void RegisterVideoSsrc(uint32 video_ssrc);
 
+  // Register SSRC that has a higher priority for sending. Multiple SSRCs can
+  // be registered.
+  // Note that it is not expected to register many SSRCs with this method.
+  // Because IsHigherPriority() is done in linear time.

[miu, 2014/07/16 22:55:56]

nit: s/done/determined/

[Alpha Left Google, 2014/07/17 00:12:56]

Done.

+  void RegisterPrioritySsrc(uint32 ssrc);
+
   // PacedPacketSender implementation.
   virtual bool SendPackets(const SendPacketVector& packets) OVERRIDE;
   virtual bool ResendPackets(const SendPacketVector& packets,
                              base::TimeDelta dedupe_window) OVERRIDE;
   virtual bool SendRtcpPacket(uint32 ssrc, PacketRef packet) OVERRIDE;
   virtual void CancelSendingPacket(const PacketKey& packet_key) OVERRIDE;
 
  private:
   // Actually sends the packets to the transport.
   void SendStoredPackets();
@@ skipping 22 matching lines @@
 
   bool empty() const;
   size_t size() const;
 
   // Returns the next packet to send. RTCP packets have highest priority,
   // resend packets have second highest priority and then comes everything
   // else.
   PacketRef GetNextPacket(PacketType* packet_type,
                           PacketKey* packet_key);
 
+  // Returns true if the packet should have a higher priority.
+  bool IsHighPriority(const PacketKey& packet_key) const;
+
   base::TickClock* const clock_;  // Not owned by this class.
   LoggingImpl* const logging_;    // Not owned by this class.
   PacketSender* transport_;       // Not owned by this class.
   scoped_refptr<base::SingleThreadTaskRunner> transport_task_runner_;
   uint32 audio_ssrc_;
   uint32 video_ssrc_;
-  std::map<PacketKey, std::pair<PacketType, PacketRef> > packet_list_;
+
+  // Set of SSRCs that have higher priority. This is a vector instead of a
+  // set because there's only very few in it (most likely 1).
+  std::vector<uint32> priority_ssrcs_;
+  typedef std::map<PacketKey, std::pair<PacketType, PacketRef> > PacketList;
+  PacketList packet_list_;
+  PacketList priority_packet_list_;
   std::map<PacketKey, base::TimeTicks> sent_time_;
   std::map<PacketKey, base::TimeTicks> sent_time_buffer_;
 
   // Maximum burst size for the next three bursts.
   size_t max_burst_size_;
   size_t next_max_burst_size_;
   size_t next_next_max_burst_size_;
   // Number of packets already sent in the current burst.
   size_t current_burst_size_;
   // This is when the current burst ends.
   base::TimeTicks burst_end_;
 
   State state_;
 
   // NOTE: Weak pointers must be invalidated before all other member variables.
   base::WeakPtrFactory<PacedSender> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(PacedSender);
 };
 
 }  // namespace cast
 }  // namespace media
 
 #endif  // MEDIA_CAST_NET_PACING_PACED_SENDER_H_