Implements RTP header dumping.

chrome/browser/media/webrtc_rtp_dump_handler.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 CHROME_BROWSER_MEDIA_WEBRTC_RTP_DUMP_HANDLER_H_
+#define CHROME_BROWSER_MEDIA_WEBRTC_RTP_DUMP_HANDLER_H_
+
+#include "base/basictypes.h"
+#include "base/callback.h"
+#include "base/files/file_path.h"
+
+namespace base {
+class FilePath;
+}  // namespace base
+
+class WebRtcRtpDumpWriter;
+
+// WebRtcRtpDumpHandler handles operations regarding the WebRTC RTP dump:
+// - Starts or stops the RTP dumping on behalf of the client.
+// - Stops the RTP dumping when the max dump file size is reached.
+// - Writes the dump file.
+// - Provides the dump file to the client code to be uploaded when
+//   ReleaseRtpDump is called.
+// All public methods should be called on the IO thread.
+class WebRtcRtpDumpHandler {
+ public:
+  struct PacketType {
+    bool incoming;
+    bool outgoing;
+  };
+
+  typedef base::Callback<void(bool success, const base::FilePath& dump_file)>
+      ReleaseDumpCallback;
+
+  // The caller must make sure |dump_dir| exists. RTP dump files are saved under
+  // |dump_dir| as "rtpdump_XXXXX.gz".

[Henrik Grunell, 2014/05/07 09:38:19]

Explain in the comment what XXXXX is. How is filename uniqueness ensured across
tabs and streams?

+  explicit WebRtcRtpDumpHandler(const base::FilePath& dump_dir);
+  virtual ~WebRtcRtpDumpHandler();
+
+  // Incoming/outgoing dumping can be started separately. Returns true if called
+  // in a valid state, i.e. dumping has not been started for any type specified
+  // in |type|.
+  bool StartDump(const PacketType& type);
+
+  // Incoming/outgoing dumping can be stopped separately. Returns true if called
+  // in a valid state, i.e. dumping has been started and not stopped for any
+  // type specified in |type|.
+  bool StopDump(const PacketType& type);
+
+  // It should only be called when both incoming and outgoing dumping has been
+  // stopped. Returns true if it's called in a valid state and the callback will
+  // be called when it finishes writing the dump file.
+  // If the method returns true, the caller will own the dump file and should
+  // clean it up from the disk when suitable. Otherwise, the dump will be
+  // deleted before WebRtcRtpDumpHandler goes away.
+  bool ReleaseDump(const ReleaseDumpCallback& callback);
+
+  virtual void OnRtpPacket(const uint8* packet, size_t length, bool incoming);

[Henrik Grunell, 2014/05/07 09:38:19]

Add comment.

+
+ private:
+  // State transitions:
+  // initial --> STATE_NONE
+  // StartDump --> STATE_STARTED
+  // StopDump --> STATE_STOPPED
+  // ReleaseDump --> STATE_NONE
+  enum State {
+    STATE_NONE,
+    STATE_STARTED,
+    STATE_STOPPED
+  };
+
+  void OnMaxDumpSizeReached();

[Henrik Grunell, 2014/05/07 09:38:19]

My guess before looking at the implementation is that |dump_writer_| calls
these. Maybe comment these?

+  void OnWriterFlushDone(const ReleaseDumpCallback& callback,
+                         bool succeeded);
+
+  base::FilePath dump_dir_;

[Henrik Grunell, 2014/05/07 09:38:19]

Comment all member variables.

+  base::FilePath dump_path_;
+  State incoming_state_;
+  State outgoing_state_;
+  scoped_ptr<WebRtcRtpDumpWriter> dump_writer_;
+
+  DISALLOW_COPY_AND_ASSIGN(WebRtcRtpDumpHandler);
+};
+
+#endif  // CHROME_BROWSER_MEDIA_WEBRTC_RTP_DUMP_HANDLER_H_