chromium/base/memory/platform_shared_memory_region.h

// Copyright 2018 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef BASE_MEMORY_PLATFORM_SHARED_MEMORY_REGION_H_
#define BASE_MEMORY_PLATFORM_SHARED_MEMORY_REGION_H_

#include <stdint.h>

#include <optional>

#include "base/base_export.h"
#include "base/containers/span.h"
#include "base/gtest_prod_util.h"
#include "base/memory/platform_shared_memory_handle.h"
#include "base/memory/shared_memory_mapper.h"
#include "base/unguessable_token.h"
#include "build/build_config.h"

#if BUILDFLAG(IS_LINUX) || BUILDFLAG(IS_CHROMEOS)
namespace content {
class SandboxIPCHandler;
}
#endif

namespace base {
namespace subtle {

// Implementation class for shared memory regions.
//
// This class does the following:
//
// - Wraps and owns a shared memory region platform handle.
// - Provides a way to allocate a new region of platform shared memory of given
//   size.
// - Provides a way to create mapping of the region in the current process'
//   address space, under special access-control constraints (see Mode).
// - Provides methods to help transferring the handle across process boundaries.
// - Holds a 128-bit unique identifier used to uniquely identify the same
//   kernel region resource across processes (used for memory tracking).
// - Has a method to retrieve the region's size in bytes.
//
// IMPORTANT NOTE: Users should never use this directly, but
// ReadOnlySharedMemoryRegion, WritableSharedMemoryRegion or
// UnsafeSharedMemoryRegion since this is an implementation class.
class BASE_EXPORT PlatformSharedMemoryRegion { … };

}  // namespace subtle
}  // namespace base

#endif  // BASE_MEMORY_PLATFORM_SHARED_MEMORY_REGION_H_