shared_memory.h - mozsearch

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/*

 *  Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.

 *  Use of this source code is governed by a BSD-style license

 *  that can be found in the LICENSE file in the root of the source

 *  tree. An additional intellectual property rights grant can be found

 *  in the file PATENTS.  All contributing project authors may

 *  be found in the AUTHORS file in the root of the source tree.

*/

#ifndef MODULES_DESKTOP_CAPTURE_SHARED_MEMORY_H_

#define MODULES_DESKTOP_CAPTURE_SHARED_MEMORY_H_

#include <stddef.h>

#if defined(WEBRTC_WIN)

// Forward declare HANDLE in a windows.h compatible way so that we can avoid

// including windows.h.

typedef void* HANDLE;

#endif

#include <memory>

#include "rtc_base/system/rtc_export.h"

namespace webrtc {

// SharedMemory is a base class for shared memory. It stores all required

// parameters of the buffer, but doesn't have any logic to allocate or destroy

// the actual buffer. DesktopCapturer consumers that need to use shared memory

// for video frames must extend this class with creation and destruction logic

// specific for the target platform and then call

// DesktopCapturer::SetSharedMemoryFactory().

class RTC_EXPORT SharedMemory {

 public:

#if defined(WEBRTC_WIN)

  typedef HANDLE Handle;

  static const Handle kInvalidHandle;

#else

  typedef int Handle;

  static const Handle kInvalidHandle;

#endif

  void* data() const { return data_; }

  size_t size() const { return size_; }

  // Platform-specific handle of the buffer.

  Handle handle() const { return handle_; }

  // Integer identifier that can be used used by consumers of DesktopCapturer

  // interface to identify shared memory buffers it created.

  int id() const { return id_; }

  virtual ~SharedMemory() {}

  SharedMemory(const SharedMemory&) = delete;

  SharedMemory& operator=(const SharedMemory&) = delete;

 protected:

  SharedMemory(void* data, size_t size, Handle handle, int id);

  void* const data_;

  const size_t size_;

  const Handle handle_;

  const int id_;

};

// Interface used to create SharedMemory instances.

class SharedMemoryFactory {

 public:

  SharedMemoryFactory() {}

  virtual ~SharedMemoryFactory() {}

  SharedMemoryFactory(const SharedMemoryFactory&) = delete;

  SharedMemoryFactory& operator=(const SharedMemoryFactory&) = delete;

  virtual std::unique_ptr<SharedMemory> CreateSharedMemory(size_t size) = 0;

};

}  // namespace webrtc

#endif  // MODULES_DESKTOP_CAPTURE_SHARED_MEMORY_H_