1 files changed, 277 insertions, 0 deletions
diff --git a/dom/media/MediaQueue.h b/dom/media/MediaQueue.h
new file mode 100644
index 0000000000..4609493339
--- /dev/null
+++ b/dom/media/MediaQueue.h
@@ -0,0 +1,277 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et cindent: */
+/* 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/. */
+#if !defined(MediaQueue_h_)
+#  define MediaQueue_h_
+
+#  include <type_traits>
+
+#  include "mozilla/RecursiveMutex.h"
+#  include "mozilla/TaskQueue.h"
+
+#  include "nsDeque.h"
+#  include "MediaEventSource.h"
+#  include "TimeUnits.h"
+
+namespace mozilla {
+
+extern LazyLogModule gMediaDecoderLog;
+
+#  define QLOG(msg, ...)                       \
+    MOZ_LOG(gMediaDecoderLog, LogLevel::Debug, \
+            ("MediaQueue=%p " msg, this, ##__VA_ARGS__))
+
+class AudioData;
+class VideoData;
+
+template <typename T>
+struct TimestampAdjustmentTrait {
+  static const bool mValue = false;
+};
+
+template <>
+struct TimestampAdjustmentTrait<AudioData> {
+  static const bool mValue = true;
+};
+
+template <>
+struct TimestampAdjustmentTrait<VideoData> {
+  static const bool mValue = true;
+};
+
+template <typename T>
+struct NonTimestampAdjustmentTrait {
+  static const bool mValue = !TimestampAdjustmentTrait<T>::mValue;
+};
+
+template <class T>
+class MediaQueue : private nsRefPtrDeque<T> {
+ public:
+  MediaQueue()
+      : nsRefPtrDeque<T>(),
+        mRecursiveMutex("mediaqueue"),
+        mEndOfStream(false) {}
+
+  ~MediaQueue() { Reset(); }
+
+  inline size_t GetSize() const {
+    RecursiveMutexAutoLock lock(mRecursiveMutex);
+    return nsRefPtrDeque<T>::GetSize();
+  }
+
+  template <typename U,
+            std::enable_if_t<TimestampAdjustmentTrait<U>::mValue, bool> = true>
+  inline void AdjustTimeStampIfNeeded(U* aItem) {
+    static_assert(std::is_same_v<U, AudioData> || std::is_same_v<U, VideoData>);
+    if (mOffset != media::TimeUnit::Zero()) {
+      const auto prev = aItem->mTime, prevEndTime = aItem->GetEndTime();
+      aItem->mTime += mOffset;
+      if (!aItem->mTime.IsValid()) {
+        NS_WARNING("Reverting timestamp adjustment due to sample overflow!");
+        aItem->mTime = prev;
+      } else {
+        QLOG("adjusted %s sample [%" PRId64 ",%" PRId64 "] -> [%" PRId64
+             ",%" PRId64 "]",
+             std::is_same_v<U, AudioData> ? "audio" : "video",
+             prev.ToMicroseconds(), prevEndTime.ToMicroseconds(),
+             aItem->mTime.ToMicroseconds(),
+             aItem->GetEndTime().ToMicroseconds());
+      }
+    }
+  }
+
+  template <typename U, std::enable_if_t<NonTimestampAdjustmentTrait<U>::mValue,
+                                         bool> = true>
+  inline void AdjustTimeStampIfNeeded(U* aItem) {}
+
+  enum class TimestampAdjustment {
+    Enable,
+    Disable,
+  };
+  inline void PushFront(
+      T* aItem, TimestampAdjustment aIsEnabled = TimestampAdjustment::Enable) {
+    RecursiveMutexAutoLock lock(mRecursiveMutex);
+    if (aIsEnabled == TimestampAdjustment::Enable) {
+      AdjustTimeStampIfNeeded(aItem);
+    }
+    nsRefPtrDeque<T>::PushFront(aItem);
+  }
+
+  inline void Push(T* aItem) {
+    MOZ_DIAGNOSTIC_ASSERT(aItem);
+    Push(do_AddRef(aItem));
+  }
+
+  inline void Push(already_AddRefed<T> aItem) {
+    RecursiveMutexAutoLock lock(mRecursiveMutex);
+    T* item = aItem.take();
+
+    MOZ_DIAGNOSTIC_ASSERT(item);
+    MOZ_DIAGNOSTIC_ASSERT(item->GetEndTime() >= item->mTime);
+    AdjustTimeStampIfNeeded(item);
+    nsRefPtrDeque<T>::Push(dont_AddRef(item));
+    mPushEvent.Notify(RefPtr<T>(item));
+
+    // Pushing new data after queue has ended means that the stream is active
+    // again, so we should not mark it as ended.
+    if (mEndOfStream) {
+      mEndOfStream = false;
+    }
+  }
+
+  inline already_AddRefed<T> PopFront() {
+    RecursiveMutexAutoLock lock(mRecursiveMutex);
+    RefPtr<T> rv = nsRefPtrDeque<T>::PopFront();
+    if (rv) {
+      MOZ_DIAGNOSTIC_ASSERT(rv->GetEndTime() >= rv->mTime);
+      mPopFrontEvent.Notify(RefPtr<T>(rv));
+    }
+    return rv.forget();
+  }
+
+  inline already_AddRefed<T> PopBack() {
+    RecursiveMutexAutoLock lock(mRecursiveMutex);
+    return nsRefPtrDeque<T>::Pop();
+  }
+
+  inline RefPtr<T> PeekFront() const {
+    RecursiveMutexAutoLock lock(mRecursiveMutex);
+    return nsRefPtrDeque<T>::PeekFront();
+  }
+
+  inline RefPtr<T> PeekBack() const {
+    RecursiveMutexAutoLock lock(mRecursiveMutex);
+    return nsRefPtrDeque<T>::Peek();
+  }
+
+  void Reset() {
+    RecursiveMutexAutoLock lock(mRecursiveMutex);
+    nsRefPtrDeque<T>::Erase();
+    SetOffset(media::TimeUnit::Zero());
+    mEndOfStream = false;
+  }
+
+  bool AtEndOfStream() const {
+    RecursiveMutexAutoLock lock(mRecursiveMutex);
+    return GetSize() == 0 && mEndOfStream;
+  }
+
+  // Returns true if the media queue has had its last item added to it.
+  // This happens when the media stream has been completely decoded. Note this
+  // does not mean that the corresponding stream has finished playback.
+  bool IsFinished() const {
+    RecursiveMutexAutoLock lock(mRecursiveMutex);
+    return mEndOfStream;
+  }
+
+  // Informs the media queue that it won't be receiving any more items.
+  void Finish() {
+    RecursiveMutexAutoLock lock(mRecursiveMutex);
+    if (!mEndOfStream) {
+      mEndOfStream = true;
+      mFinishEvent.Notify();
+    }
+  }
+
+  // Returns the approximate number of microseconds of items in the queue.
+  int64_t Duration() const {
+    RecursiveMutexAutoLock lock(mRecursiveMutex);
+    if (GetSize() == 0) {
+      return 0;
+    }
+    T* last = nsRefPtrDeque<T>::Peek();
+    T* first = nsRefPtrDeque<T>::PeekFront();
+    return (last->GetEndTime() - first->mTime).ToMicroseconds();
+  }
+
+  void LockedForEach(nsDequeFunctor<T>& aFunctor) const {
+    RecursiveMutexAutoLock lock(mRecursiveMutex);
+    nsRefPtrDeque<T>::ForEach(aFunctor);
+  }
+
+  // Fill aResult with the elements which end later than the given time aTime.
+  void GetElementsAfter(const media::TimeUnit& aTime,
+                        nsTArray<RefPtr<T>>* aResult) {
+    GetElementsAfterStrict(aTime.ToMicroseconds(), aResult);
+  }
+
+  void GetFirstElements(uint32_t aMaxElements, nsTArray<RefPtr<T>>* aResult) {
+    RecursiveMutexAutoLock lock(mRecursiveMutex);
+    for (size_t i = 0; i < aMaxElements && i < GetSize(); ++i) {
+      *aResult->AppendElement() = nsRefPtrDeque<T>::ObjectAt(i);
+    }
+  }
+
+  uint32_t AudioFramesCount() {
+    static_assert(std::is_same_v<T, AudioData>,
+                  "Only usable with MediaQueue<AudioData>");
+    RecursiveMutexAutoLock lock(mRecursiveMutex);
+    uint32_t frames = 0;
+    for (size_t i = 0; i < GetSize(); ++i) {
+      T* v = nsRefPtrDeque<T>::ObjectAt(i);
+      frames += v->Frames();
+    }
+    return frames;
+  }
+
+  bool SetOffset(const media::TimeUnit& aOffset) {
+    if (!aOffset.IsValid()) {
+      QLOG("Invalid offset!");
+      return false;
+    }
+    RecursiveMutexAutoLock lock(mRecursiveMutex);
+    mOffset = aOffset;
+    QLOG("Set media queue offset %" PRId64, mOffset.ToMicroseconds());
+    return true;
+  }
+
+  media::TimeUnit GetOffset() const {
+    RecursiveMutexAutoLock lock(mRecursiveMutex);
+    return mOffset;
+  }
+
+  MediaEventSource<RefPtr<T>>& PopFrontEvent() { return mPopFrontEvent; }
+
+  MediaEventSource<RefPtr<T>>& PushEvent() { return mPushEvent; }
+
+  MediaEventSource<void>& FinishEvent() { return mFinishEvent; }
+
+ private:
+  // Extracts elements from the queue into aResult, in order.
+  // Elements whose end time is before or equal to aTime are ignored.
+  void GetElementsAfterStrict(int64_t aTime, nsTArray<RefPtr<T>>* aResult) {
+    RecursiveMutexAutoLock lock(mRecursiveMutex);
+    if (GetSize() == 0) return;
+    size_t i;
+    for (i = GetSize() - 1; i > 0; --i) {
+      T* v = nsRefPtrDeque<T>::ObjectAt(i);
+      if (v->GetEndTime().ToMicroseconds() < aTime) break;
+    }
+    for (; i < GetSize(); ++i) {
+      RefPtr<T> elem = nsRefPtrDeque<T>::ObjectAt(i);
+      if (elem->GetEndTime().ToMicroseconds() > aTime) {
+        aResult->AppendElement(elem);
+      }
+    }
+  }
+
+  mutable RecursiveMutex mRecursiveMutex MOZ_UNANNOTATED;
+  MediaEventProducer<RefPtr<T>> mPopFrontEvent;
+  MediaEventProducer<RefPtr<T>> mPushEvent;
+  MediaEventProducer<void> mFinishEvent;
+  // True when we've decoded the last frame of data in the
+  // bitstream for which we're queueing frame data.
+  bool mEndOfStream;
+  // This offset will be added to any data pushed into the queue. We use it when
+  // the media queue starts receiving looped data, which timestamp needs to be
+  // modified.
+  media::TimeUnit mOffset;
+};
+
+}  // namespace mozilla
+
+#  undef QLOG
+
+#endif