chromium/base/memory/shared_memory_mapping.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_SHARED_MEMORY_MAPPING_H_
#define BASE_MEMORY_SHARED_MEMORY_MAPPING_H_

#include <cstddef>

#include "base/base_export.h"
#include "base/check.h"
#include "base/containers/span.h"
#include "base/memory/raw_ptr.h"
#include "base/memory/shared_memory_mapper.h"
#include "base/memory/shared_memory_safety_checker.h"
#include "base/unguessable_token.h"

namespace base {

namespace subtle {
class PlatformSharedMemoryRegion;
}  // namespace subtle

// Base class for scoped handles to a shared memory mapping created from a
// shared memory region. Created shared memory mappings remain valid even if the
// creator region is transferred or destroyed.
//
// Each mapping has an UnguessableToken that identifies the shared memory region
// it was created from. This is used for memory metrics, to avoid overcounting
// shared memory.
class BASE_EXPORT SharedMemoryMapping { … };

// Class modeling a read-only mapping of a shared memory region into the
// current process' address space. This is created by ReadOnlySharedMemoryRegion
// instances.
class BASE_EXPORT ReadOnlySharedMemoryMapping : public SharedMemoryMapping { … };

// Class modeling a writable mapping of a shared memory region into the
// current process' address space. This is created by *SharedMemoryRegion
// instances.
class BASE_EXPORT WritableSharedMemoryMapping : public SharedMemoryMapping { … };

}  // namespace base

#endif  // BASE_MEMORY_SHARED_MEMORY_MAPPING_H_