xref: /external/chromium_org/content/common/gpu/media/v4l2_video_device.h

// Copyright 2014 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.
//
// This file defines the V4L2Device interface which is used by the
// V4L2DecodeAccelerator class to delegate/pass the device specific
// handling of any of the functionalities.

#ifndef CONTENT_COMMON_GPU_MEDIA_V4L2_VIDEO_DEVICE_H_
#define CONTENT_COMMON_GPU_MEDIA_V4L2_VIDEO_DEVICE_H_

namespace content {

class V4L2Device {
 public:
  V4L2Device();
  virtual ~V4L2Device();

  // Tries to create and initialize an appropriate V4L2Device object for the
  // current platform and returns a scoped_ptr<V4L2Device> on success else
  // returns NULL.
  static scoped_ptr<V4L2Device> Create();

  // Parameters and return value are the same as for the standard ioctl() system
  // call.
  virtual int Ioctl(int request, void* arg) = 0;

  // This method sleeps until either:
  // - SetDevicePollInterrupt() is called (on another thread),
  // - |poll_device| is true, and there is new data to be read from the device,
  //   or an event from the device has arrived; in the latter case
  //   |*event_pending| will be set to true.
  // Returns false on error, true otherwise.
  // This method should be called from a separate thread.
  virtual bool Poll(bool poll_device, bool* event_pending) = 0;

  // These methods are used to interrupt the thread sleeping on Poll() and force
  // it to return regardless of device state, which is usually when the client
  // is no longer interested in what happens with the device (on cleanup,
  // client state change, etc.). When SetDevicePollInterrupt() is called, Poll()
  // will return immediately, and any subsequent calls to it will also do so
  // until ClearDevicePollInterrupt() is called.
  virtual bool SetDevicePollInterrupt() = 0;
  virtual bool ClearDevicePollInterrupt() = 0;

  // Wrappers for standard mmap/munmap system calls.
  virtual void* Mmap(void* addr,
                     unsigned int len,
                     int prot,
                     int flags,
                     unsigned int offset) = 0;
  virtual void Munmap(void* addr, unsigned int len) = 0;
};
}  //  namespace content

#endif  //  CONTENT_COMMON_GPU_MEDIA_V4L2_VIDEO_DEVICE_H_