Cast: Added a new RawEventSubscriber implementation for use in cast extension.

media/cast/logging/encoding_event_subscriber.h

+// Copyright 2014 The Chromium Authors. All rights reserved.

[Alpha Left Google, 2014/02/11 22:14:03]

Isn't this subscriber specific to Cast Streaming API? This feels like it should
belong to chrome/media/renderer.

[Alpha Left Google, 2014/02/11 22:49:13]

Nevermind my previous comment. Putting it in this dir is fine.

[imcheng, 2014/02/12 08:44:13]

Ack.

+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef MEDIA_CAST_LOGGING_ENCODING_EVENT_SUBSCRIBER_H_
+#define MEDIA_CAST_LOGGING_ENCODING_EVENT_SUBSCRIBER_H_
+
+#include <map>
+
+#include "base/memory/linked_ptr.h"
+#include "base/single_thread_task_runner.h"
+#include "base/threading/thread_checker.h"
+#include "media/cast/logging/proto/raw_events.pb.h"
+#include "media/cast/logging/raw_event_subscriber.h"
+
+namespace media {
+namespace cast {
+
+typedef std::map<RtpTimestamp,
+                 linked_ptr<media::cast::proto::AggregatedFrameEvent> >
+    FrameEventMap;
+typedef std::map<RtpTimestamp,
+                 linked_ptr<media::cast::proto::AggregatedPacketEvent> >
+    PacketEventMap;
+typedef std::map<CastLoggingEvent,
+                 linked_ptr<media::cast::proto::AggregatedGenericEvent> >
+    GenericEventMap;
+
+// A RawEventSubscriber implementation that subscribes to events,
+// encodes them in protocol buffer format, and aggregates them into a more
+// compact structure.
+// TODO(imcheng): Implement event filtering and windowing based on size.
+class EncodingEventSubscriber : public RawEventSubscriber {
+ public:
+  // |main_thread_proxy|: Only used for ensuring the subscriber is only called

[Alpha Left Google, 2014/02/11 22:49:13]

This is not very useful. I suggest you remove this. We can already ensure the
caller of the construct that it runs on the main thread.

[imcheng, 2014/02/12 08:44:13]

I suppose that's true. The only difference it will blow up later rather than
sooner if it were somehow constructed on a thread other than main.

+  // on the main thread. This object does not keep a reference on it.
+  explicit EncodingEventSubscriber(
+      const scoped_refptr<base::SingleThreadTaskRunner>& main_thread_proxy);
+
+  virtual ~EncodingEventSubscriber();
+
+  virtual void OnReceiveFrameEvent(const FrameEvent& frame_event) OVERRIDE;

[Alpha Left Google, 2014/02/11 22:49:13]

nit:

// RawReventSubscriber implementations.
 

[imcheng, 2014/02/12 08:44:13]

Done.

+
+  virtual void OnReceivePacketEvent(const PacketEvent& packet_event) OVERRIDE;
+
+  virtual void OnReceiveGenericEvent(const GenericEvent& generic_event)
+      OVERRIDE;
+
+  // Assigns frame events received so far to |frame_events| and clears them
+  // from this object.
+  void GetFrameEventsAndReset(FrameEventMap* frame_events);
+
+  // Assigns packet events received so far to |packet_events| and clears them
+  // from this object.
+  void GetPacketEventsAndReset(PacketEventMap* packet_events);
+
+  // Assigns generic events received so far to |generic_events| and clears them
+  // from this object.
+  void GetGenericEventsAndReset(GenericEventMap* generic_events);
+
+ private:
+  FrameEventMap frame_event_map_;
+  PacketEventMap packet_event_map_;
+  GenericEventMap generic_event_map_;
+
+  // All functions must be called on the main thread.
+  base::ThreadChecker thread_checker_;
+
+  DISALLOW_COPY_AND_ASSIGN(EncodingEventSubscriber);
+};
+
+}  // namespace cast
+}  // namespace media
+
+#endif  // MEDIA_CAST_LOGGING_ENCODING_EVENT_SUBSCRIBER_H_