chromium/base/metrics/histogram_shared_memory.h

// Copyright 2023 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_METRICS_HISTOGRAM_SHARED_MEMORY_H_
#define BASE_METRICS_HISTOGRAM_SHARED_MEMORY_H_

#include <optional>
#include <string_view>

#include "base/base_export.h"
#include "base/command_line.h"
#include "base/feature_list.h"
#include "base/memory/unsafe_shared_memory_region.h"
#include "base/metrics/persistent_memory_allocator.h"
#include "base/process/launch.h"
#include "build/build_config.h"

#if BUILDFLAG(IS_POSIX) && !BUILDFLAG(IS_APPLE)
#include "base/files/platform_file.h"
#include "base/posix/global_descriptors.h"
#endif

#if !BUILDFLAG(USE_BLINK)
#error "This is only intended for platforms that use blink."
#endif

namespace base {

BASE_EXPORT BASE_DECLARE_FEATURE(kPassHistogramSharedMemoryOnLaunch);

// Helper structure to create and return a shared memory region and a histogram
// allocator over top of it. Once returned it is expected that the caller will
// move both the memory regions and the allocator out of the struct and into
// it's own appropriate state variables. Note that the memory region must
// outlive the allocator.
struct BASE_EXPORT HistogramSharedMemory { … };

}  // namespace base

#endif  // BASE_METRICS_HISTOGRAM_SHARED_MEMORY_H_