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// Copyright (c) 2012 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 "base/memory/ref_counted.h"
namespace media {
class VideoFrame;
namespace cc {
// Threading notes: This class may be used in a multi threaded manner.
// Specifically, the implementation may call GetCurrentFrame() or
// PutCurrentFrame() from the compositor thread. If so, the caller is
// responsible for making sure Client::DidReceiveFrame() and
// Client::DidUpdateMatrix() are only called from this same thread.
class VideoFrameProvider {
virtual ~VideoFrameProvider() {}
class Client {
// Provider will call this method to tell the client to stop using it.
// StopUsingProvider() may be called from any thread. The client should
// block until it has PutCurrentFrame() any outstanding frames.
virtual void StopUsingProvider() = 0;
// Notifies the provider's client that a call to GetCurrentFrame() will
// return new data.
virtual void DidReceiveFrame() = 0;
// Notifies the provider's client of a new UV transform matrix to be used.
virtual void DidUpdateMatrix(const float* matrix) = 0;
virtual ~Client() {}
// May be called from any thread, but there must be some external guarantee
// that the provider is not destroyed before this call returns.
virtual void SetVideoFrameProviderClient(Client* client) = 0;
// This function places a lock on the current frame and returns a pointer to
// it. Calls to this method should always be followed with a call to
// PutCurrentFrame().
// Only the current provider client should call this function.
virtual scoped_refptr<media::VideoFrame> GetCurrentFrame() = 0;
// This function releases the lock on the video frame. It should always be
// called after GetCurrentFrame(). Frames passed into this method
// should no longer be referenced after the call is made. Only the current
// provider client should call this function.
virtual void PutCurrentFrame(
const scoped_refptr<media::VideoFrame>& frame) = 0;
} // namespace cc