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// Copyright 2015 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "base/base_export.h"
#include "base/optional.h"
#include "base/threading/platform_thread.h"
#include "build/build_config.h"
namespace base {
namespace internal {
struct ThreadPriorityToNiceValuePair {
ThreadPriority priority;
int nice_value;
// The elements must be listed in the order of increasing priority (lowest
// priority first), that is, in the order of decreasing nice values (highest
// nice value first).
const ThreadPriorityToNiceValuePair kThreadPriorityToNiceValueMap[4];
// Returns the nice value matching |priority| based on the platform-specific
// implementation of kThreadPriorityToNiceValueMap.
int ThreadPriorityToNiceValue(ThreadPriority priority);
// Returns the ThreadPrioirty matching |nice_value| based on the platform-
// specific implementation of kThreadPriorityToNiceValueMap.
BASE_EXPORT ThreadPriority NiceValueToThreadPriority(int nice_value);
// If non-nullopt, this return value will be used as the platform-specific
// result of CanIncreaseThreadPriority().
Optional<bool> CanIncreaseCurrentThreadPriorityForPlatform(
ThreadPriority priority);
// Allows platform specific tweaks to the generic POSIX solution for
// SetCurrentThreadPriority(). Returns true if the platform-specific
// implementation handled this |priority| change, false if the generic
// implementation should instead proceed.
bool SetCurrentThreadPriorityForPlatform(ThreadPriority priority);
// If non-null, this return value will be used as the platform-specific result
// of CanIncreaseThreadPriority().
Optional<ThreadPriority> GetCurrentThreadPriorityForPlatform();
#if defined(OS_LINUX)
// Current thread id is cached in thread local storage for performance reasons.
// In some rare cases it's important to clear that cache explicitly (e.g. after
// going through clone() syscall which does not call pthread_atfork()
// handlers).
BASE_EXPORT void ClearTidCache();
#endif // defined(OS_LINUX)
} // namespace internal
} // namespace base