gecko-dev/dom/media/webm/NesteggPacketHolder.h

/* -*- 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(NesteggPacketHolder_h_)
#define NesteggPacketHolder_h_

#include <stdint.h>
#include "nsAutoRef.h"
#include "nestegg/nestegg.h"

namespace mozilla {

// Holds a nestegg_packet, and its file offset. This is needed so we
// know the offset in the file we've played up to, in order to calculate
// whether it's likely we can play through to the end without needing
// to stop to buffer, given the current download rate.
class NesteggPacketHolder {
 public:
  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(NesteggPacketHolder)
  NesteggPacketHolder()
      : mPacket(nullptr),
        mOffset(-1),
        mTimestamp(-1),
        mDuration(-1),
        mTrack(0),
        mIsKeyframe(false) {}

  bool Init(nestegg_packet* aPacket, int64_t aOffset, unsigned aTrack,
            bool aIsKeyframe) {
    uint64_t timestamp_ns;
    if (nestegg_packet_tstamp(aPacket, &timestamp_ns) == -1) {
      return false;
    }

    // We store the timestamp as signed microseconds so that it's easily
    // comparable to other timestamps we have in the system.
    mTimestamp = timestamp_ns / 1000;
    mPacket = aPacket;
    mOffset = aOffset;
    mTrack = aTrack;
    mIsKeyframe = aIsKeyframe;

    uint64_t duration_ns;
    if (!nestegg_packet_duration(aPacket, &duration_ns)) {
      mDuration = duration_ns / 1000;
    }
    return true;
  }

  nestegg_packet* Packet() {
    MOZ_ASSERT(IsInitialized());
    return mPacket;
  }
  int64_t Offset() {
    MOZ_ASSERT(IsInitialized());
    return mOffset;
  }
  int64_t Timestamp() {
    MOZ_ASSERT(IsInitialized());
    return mTimestamp;
  }
  int64_t Duration() {
    MOZ_ASSERT(IsInitialized());
    return mDuration;
  }
  unsigned Track() {
    MOZ_ASSERT(IsInitialized());
    return mTrack;
  }
  bool IsKeyframe() {
    MOZ_ASSERT(IsInitialized());
    return mIsKeyframe;
  }

 private:
  ~NesteggPacketHolder() { nestegg_free_packet(mPacket); }

  bool IsInitialized() { return mOffset >= 0; }

  nestegg_packet* mPacket;

  // Offset in bytes. This is the offset of the end of the Block
  // which contains the packet.
  int64_t mOffset;

  // Packet presentation timestamp in microseconds.
  int64_t mTimestamp;

  // Packet duration in microseconds; -1 if unknown or retrieval failed.
  int64_t mDuration;

  // Track ID.
  unsigned mTrack;

  // Does this packet contain a keyframe?
  bool mIsKeyframe;

  // Copy constructor and assignment operator not implemented. Don't use them!
  NesteggPacketHolder(const NesteggPacketHolder& aOther);
  NesteggPacketHolder& operator=(NesteggPacketHolder const& aOther);
};

// Queue for holding nestegg packets.
class WebMPacketQueue {
 public:
  int32_t GetSize() { return mQueue.size(); }

  void Push(NesteggPacketHolder* aItem) { mQueue.push_back(aItem); }

  void PushFront(NesteggPacketHolder* aItem) {
    mQueue.push_front(std::move(aItem));
  }

  already_AddRefed<NesteggPacketHolder> PopFront() {
    RefPtr<NesteggPacketHolder> result = mQueue.front().forget();
    mQueue.pop_front();
    return result.forget();
  }

  void Reset() {
    while (!mQueue.empty()) {
      mQueue.pop_front();
    }
  }

 private:
  std::deque<RefPtr<NesteggPacketHolder>> mQueue;
};

}  // namespace mozilla

#endif