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// Copyright 2024 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef COMPONENTS_PERFORMANCE_MANAGER_EMBEDDER_SCOPED_GLOBAL_SCENARIO_MEMORY_H_
#define COMPONENTS_PERFORMANCE_MANAGER_EMBEDDER_SCOPED_GLOBAL_SCENARIO_MEMORY_H_
#include <optional>
#include "components/performance_manager/scenario_api/performance_scenario_memory.h"
namespace base {
class SharedMemoryMapper;
}
namespace performance_manager {
// A scoped object that maps in writable shared memory for the global
// performance scenario state as long as it exists. The embedder should create
// one of these on startup that lasts for the lifetime of the browser.
// Performance Manager will update the state, which can be read from any process
// using functions in
// //components/performance_manager/scenario_api/performance_scenarios.h.
class ScopedGlobalScenarioMemory {
public:
// If `mapper` is non-null, it will be used to map the shared scenario
// memory region. This is useful for testing.
explicit ScopedGlobalScenarioMemory(
base::SharedMemoryMapper* mapper = nullptr);
~ScopedGlobalScenarioMemory();
ScopedGlobalScenarioMemory(const ScopedGlobalScenarioMemory&) = delete;
ScopedGlobalScenarioMemory& operator=(const ScopedGlobalScenarioMemory&) =
delete;
private:
// The browser process also maps in the global scenario memory read-only. The
// //components/performance_manager/scenario_api/performance_scenarios.h
// query functions will read from this for ScenarioScope::kGlobal.
std::optional<performance_scenarios::ScopedReadOnlyScenarioMemory>
read_only_mapping_;
// True when the writable shared memory region was successfully installed.
bool writable_global_memory_installed_ = false;
};
} // namespace performance_manager
#endif // COMPONENTS_PERFORMANCE_MANAGER_EMBEDDER_SCOPED_GLOBAL_SCENARIO_MEMORY_H_
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