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      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 MEDIA_CAST_RTCP_RECEIVER_RTCP_EVENT_SUBSCRIBER_H_
      6 #define MEDIA_CAST_RTCP_RECEIVER_RTCP_EVENT_SUBSCRIBER_H_
      7 
      8 #include <map>
      9 
     10 #include "base/threading/thread_checker.h"
     11 #include "media/cast/logging/logging_defines.h"
     12 #include "media/cast/logging/raw_event_subscriber.h"
     13 #include "media/cast/net/rtcp/rtcp_defines.h"
     14 
     15 namespace media {
     16 namespace cast {
     17 
     18 // A RawEventSubscriber implementation with the following properties:
     19 // - Only processes raw event types that are relevant for sending from cast
     20 //   receiver to cast sender via RTCP.
     21 // - Captures information to be sent over to RTCP from raw event logs into the
     22 //   more compact RtcpEvent struct.
     23 // - Orders events by RTP timestamp with a multimap.
     24 // - Internally, the map is capped at a maximum size configurable by the caller.
     25 //   The subscriber only keeps the most recent events (determined by RTP
     26 //   timestamp) up to the size limit.
     27 class ReceiverRtcpEventSubscriber : public RawEventSubscriber {
     28  public:
     29   typedef std::multimap<RtpTimestamp, RtcpEvent> RtcpEventMultiMap;
     30 
     31   // |max_size_to_retain|: The object will keep up to |max_size_to_retain|
     32   // events
     33   // in the map. Once threshold has been reached, an event with the smallest
     34   // RTP timestamp will be removed.
     35   // |type|: Determines whether the subscriber will process only audio or video
     36   // events.
     37   ReceiverRtcpEventSubscriber(const size_t max_size_to_retain,
     38       EventMediaType type);
     39 
     40   virtual ~ReceiverRtcpEventSubscriber();
     41 
     42   // RawEventSubscriber implementation.
     43   virtual void OnReceiveFrameEvent(const FrameEvent& frame_event) OVERRIDE;
     44   virtual void OnReceivePacketEvent(const PacketEvent& packet_event) OVERRIDE;
     45 
     46   // Assigns events collected to |rtcp_events| and clears them from this
     47   // object.
     48   void GetRtcpEventsAndReset(RtcpEventMultiMap* rtcp_events);
     49 
     50  private:
     51   // If |rtcp_events_.size()| exceeds |max_size_to_retain_|, remove an oldest
     52   // entry (determined by RTP timestamp) so its size no greater than
     53   // |max_size_to_retain_|.
     54   void TruncateMapIfNeeded();
     55 
     56   // Returns |true| if events of |event_type| and |media_type|
     57   // should be processed.
     58   bool ShouldProcessEvent(CastLoggingEvent event_type,
     59       EventMediaType media_type);
     60 
     61   const size_t max_size_to_retain_;
     62   EventMediaType type_;
     63 
     64   // The key should really be something more than just a RTP timestamp in order
     65   // to differentiate between video and audio frames, but since the
     66   // implementation doesn't mix audio and video frame events, RTP timestamp
     67   // only as key is fine.
     68   RtcpEventMultiMap rtcp_events_;
     69 
     70   // Ensures methods are only called on the main thread.
     71   base::ThreadChecker thread_checker_;
     72 
     73   DISALLOW_COPY_AND_ASSIGN(ReceiverRtcpEventSubscriber);
     74 };
     75 
     76 }  // namespace cast
     77 }  // namespace media
     78 
     79 #endif  // MEDIA_CAST_RTCP_RECEIVER_RTCP_EVENT_SUBSCRIBER_H_
     80