// Copyright 2013 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.

#include "cobalt/media/base/video_frame_pool.h"

#include <list>

#include "base/basictypes.h"
#include "base/bind.h"
#include "base/memory/ref_counted.h"
#include "base/synchronization/lock.h"

namespace cobalt {
namespace media {

class VideoFramePool::PoolImpl
    : public base::RefCountedThreadSafe<VideoFramePool::PoolImpl> {
 public:
  PoolImpl();

  // See VideoFramePool::CreateFrame() for usage.
  scoped_refptr<VideoFrame> CreateFrame(VideoPixelFormat format,
                                        const gfx::Size& coded_size,
                                        const gfx::Rect& visible_rect,
                                        const gfx::Size& natural_size,
                                        base::TimeDelta timestamp);

  // Shuts down the frame pool and releases all frames in |frames_|.
  // Once this is called frames will no longer be inserted back into
  // |frames_|.
  void Shutdown();

  size_t GetPoolSizeForTesting() const { return frames_.size(); }

 private:
  friend class base::RefCountedThreadSafe<VideoFramePool::PoolImpl>;
  ~PoolImpl();

  // Called when the frame wrapper gets destroyed.
  // |frame| is the actual frame that was wrapped and is placed
  // in |frames_| by this function so it can be reused.
  void FrameReleased(const scoped_refptr<VideoFrame>& frame);

  base::Lock lock_;
  bool is_shutdown_;
  std::list<scoped_refptr<VideoFrame> > frames_;

  DISALLOW_COPY_AND_ASSIGN(PoolImpl);
};

VideoFramePool::PoolImpl::PoolImpl() : is_shutdown_(false) {}

VideoFramePool::PoolImpl::~PoolImpl() { DCHECK(is_shutdown_); }

scoped_refptr<VideoFrame> VideoFramePool::PoolImpl::CreateFrame(
    VideoPixelFormat format, const gfx::Size& coded_size,
    const gfx::Rect& visible_rect, const gfx::Size& natural_size,
    base::TimeDelta timestamp) {
  base::AutoLock auto_lock(lock_);
  DCHECK(!is_shutdown_);

  scoped_refptr<VideoFrame> frame;
  while (!frame.get() && !frames_.empty()) {
    scoped_refptr<VideoFrame> pool_frame = frames_.front();
    frames_.pop_front();

    if (pool_frame->format() == format &&
        pool_frame->coded_size() == coded_size &&
        pool_frame->visible_rect() == visible_rect &&
        pool_frame->natural_size() == natural_size) {
      frame = pool_frame;
      frame->set_timestamp(timestamp);
      frame->metadata()->Clear();
      break;
    }
  }

  if (!frame.get()) {
    frame = VideoFrame::CreateZeroInitializedFrame(
        format, coded_size, visible_rect, natural_size, timestamp);
    // This can happen if the arguments are not valid.
    if (!frame) {
      LOG(ERROR) << "Failed to create a video frame";
      return NULL;
    }
  }

  scoped_refptr<VideoFrame> wrapped_frame = VideoFrame::WrapVideoFrame(
      frame, frame->format(), frame->visible_rect(), frame->natural_size());
  wrapped_frame->AddDestructionObserver(
      base::Bind(&VideoFramePool::PoolImpl::FrameReleased, this, frame));
  return wrapped_frame;
}

void VideoFramePool::PoolImpl::Shutdown() {
  base::AutoLock auto_lock(lock_);
  is_shutdown_ = true;
  frames_.clear();
}

void VideoFramePool::PoolImpl::FrameReleased(
    const scoped_refptr<VideoFrame>& frame) {
  base::AutoLock auto_lock(lock_);
  if (is_shutdown_) return;

  frames_.push_back(frame);
}

VideoFramePool::VideoFramePool() : pool_(new PoolImpl()) {}

VideoFramePool::~VideoFramePool() { pool_->Shutdown(); }

scoped_refptr<VideoFrame> VideoFramePool::CreateFrame(
    VideoPixelFormat format, const gfx::Size& coded_size,
    const gfx::Rect& visible_rect, const gfx::Size& natural_size,
    base::TimeDelta timestamp) {
  return pool_->CreateFrame(format, coded_size, visible_rect, natural_size,
                            timestamp);
}

size_t VideoFramePool::GetPoolSizeForTesting() const {
  return pool_->GetPoolSizeForTesting();
}

}  // namespace media
}  // namespace cobalt