diff -r 000000000000 -r 6474c204b198 media/mtransport/rlogringbuffer.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/media/mtransport/rlogringbuffer.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,124 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// Some of this code is cut-and-pasted from nICEr. Copyright is:
+
+/*
+Copyright (c) 2007, Adobe Systems, Incorporated
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+* Redistributions of source code must retain the above copyright
+  notice, this list of conditions and the following disclaimer.
+
+* Redistributions in binary form must reproduce the above copyright
+  notice, this list of conditions and the following disclaimer in the
+  documentation and/or other materials provided with the distribution.
+
+* Neither the name of Adobe Systems, Network Resonance nor the names of its
+  contributors may be used to endorse or promote products derived from
+  this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/* Original author: bcampen@mozilla.com */
+
+/*
+   This file defines an r_dest_vlog that can be used to accumulate log messages
+   for later inspection/filtering. The intent is to use this for interactive
+   debug purposes on an about:webrtc page or similar.
+*/
+
+#ifndef rlogringbuffer_h__
+#define rlogringbuffer_h__
+
+#include <stdint.h>
+
+#include <deque>
+#include <string>
+#include <vector>
+
+#include "mozilla/Mutex.h"
+
+#include "m_cpp_utils.h"
+
+namespace mozilla {
+
+class RLogRingBuffer {
+  public:
+    /*
+       NB: These are not threadsafe, nor are they safe to call during static
+       init/deinit.
+    */
+    static RLogRingBuffer* CreateInstance();
+    static RLogRingBuffer* GetInstance();
+    static void DestroyInstance();
+
+    /*
+       Retrieves log statements that match a given substring, subject to a
+       limit. |matching_logs| will be filled in chronological order (front()
+       is oldest, back() is newest). |limit| == 0 will be interpreted as no
+       limit.
+    */
+    void Filter(const std::string& substring,
+                uint32_t limit,
+                std::deque<std::string>* matching_logs);
+
+    void FilterAny(const std::vector<std::string>& substrings,
+                   uint32_t limit,
+                   std::deque<std::string>* matching_logs);
+
+    inline void GetAny(uint32_t limit,
+                       std::deque<std::string>* matching_logs) {
+      Filter("", limit, matching_logs);
+    }
+
+    void SetLogLimit(uint32_t new_limit);
+
+    void Log(std::string&& log);
+
+  private:
+    RLogRingBuffer();
+    ~RLogRingBuffer();
+    void RemoveOld();
+    static RLogRingBuffer* instance;
+
+    /*
+     * Might be worthwhile making this a circular buffer, but I think it is
+     * preferable to take up as little space as possible if no logging is
+     * happening/the ringbuffer is not being used.
+    */
+    std::deque<std::string> log_messages_;
+    /* Max size of log buffer (should we use time-depth instead/also?) */
+    uint32_t log_limit_;
+    OffTheBooksMutex mutex_;
+
+    DISALLOW_COPY_ASSIGN(RLogRingBuffer);
+}; // class RLogRingBuffer
+
+} // namespace mozilla
+
+#endif // rlogringbuffer_h__
+
+