diff -r 000000000000 -r 6474c204b198 content/media/StreamBuffer.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/content/media/StreamBuffer.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,104 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* 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/. */
+
+#include "StreamBuffer.h"
+#include "prlog.h"
+#include <algorithm>
+
+namespace mozilla {
+
+#ifdef PR_LOGGING
+extern PRLogModuleInfo* gMediaStreamGraphLog;
+#define STREAM_LOG(type, msg) PR_LOG(gMediaStreamGraphLog, type, msg)
+#else
+#define STREAM_LOG(type, msg)
+#endif
+
+#ifdef DEBUG
+void
+StreamBuffer::DumpTrackInfo() const
+{
+  STREAM_LOG(PR_LOG_ALWAYS, ("DumpTracks: mTracksKnownTime %lld", mTracksKnownTime));
+  for (uint32_t i = 0; i < mTracks.Length(); ++i) {
+    Track* track = mTracks[i];
+    if (track->IsEnded()) {
+      STREAM_LOG(PR_LOG_ALWAYS, ("Track[%d] %d: ended", i, track->GetID()));
+    } else {
+      STREAM_LOG(PR_LOG_ALWAYS, ("Track[%d] %d: %lld", i, track->GetID(),
+                                 track->GetEndTimeRoundDown()));
+    }
+  }
+}
+#endif
+
+StreamTime
+StreamBuffer::GetEnd() const
+{
+  StreamTime t = mTracksKnownTime;
+  for (uint32_t i = 0; i < mTracks.Length(); ++i) {
+    Track* track = mTracks[i];
+    if (!track->IsEnded()) {
+      t = std::min(t, track->GetEndTimeRoundDown());
+    }
+  }
+  return t;
+}
+
+StreamTime
+StreamBuffer::GetAllTracksEnd() const
+{
+  if (mTracksKnownTime < STREAM_TIME_MAX) {
+    // A track might be added.
+    return STREAM_TIME_MAX;
+  }
+  StreamTime t = 0;
+  for (uint32_t i = 0; i < mTracks.Length(); ++i) {
+    Track* track = mTracks[i];
+    if (!track->IsEnded()) {
+      return STREAM_TIME_MAX;
+    }
+    t = std::max(t, track->GetEndTimeRoundDown());
+  }
+  return t;
+}
+
+StreamBuffer::Track*
+StreamBuffer::FindTrack(TrackID aID)
+{
+  if (aID == TRACK_NONE)
+    return nullptr;
+  for (uint32_t i = 0; i < mTracks.Length(); ++i) {
+    Track* track = mTracks[i];
+    if (track->GetID() == aID) {
+      return track;
+    }
+  }
+  return nullptr;
+}
+
+void
+StreamBuffer::ForgetUpTo(StreamTime aTime)
+{
+  // Round to nearest 50ms so we don't spend too much time pruning segments.
+  const MediaTime roundTo = MillisecondsToMediaTime(50);
+  StreamTime forget = (aTime/roundTo)*roundTo;
+  if (forget <= mForgottenTime) {
+    return;
+  }
+  mForgottenTime = forget;
+
+  for (uint32_t i = 0; i < mTracks.Length(); ++i) {
+    Track* track = mTracks[i];
+    if (track->IsEnded() && track->GetEndTimeRoundDown() <= forget) {
+      mTracks.RemoveElementAt(i);
+      --i;
+      continue;
+    }
+    TrackTicks forgetTo = std::min(track->GetEnd() - 1, track->TimeToTicksRoundDown(forget));
+    track->ForgetUpTo(forgetTo);
+  }
+}
+
+}