mirror of
https://github.com/VCMP-SqMod/SqMod.git
synced 2024-11-08 08:47:17 +01:00
4a6bfc086c
Switched to POCO library for unified platform/library interface. Deprecated the external module API. It was creating more problems than solving. Removed most built-in libraries in favor of system libraries for easier maintenance. Cleaned and secured code with help from static analyzers.
122 lines
2.3 KiB
C++
122 lines
2.3 KiB
C++
//
|
|
// AtomicFlag.h
|
|
//
|
|
// Library: Foundation
|
|
// Package: Core
|
|
// Module: AtomicFlag
|
|
//
|
|
// Definition of the AtomicFlag class.
|
|
//
|
|
// Copyright (c) 2009, Applied Informatics Software Engineering GmbH.
|
|
// and Contributors.
|
|
//
|
|
// SPDX-License-Identifier: BSL-1.0
|
|
//
|
|
|
|
|
|
#ifndef Foundation_AtomicFlag_INCLUDED
|
|
#define Foundation_AtomicFlag_INCLUDED
|
|
|
|
|
|
#include "Poco/Foundation.h"
|
|
#include <atomic>
|
|
|
|
|
|
namespace Poco {
|
|
|
|
|
|
class Foundation_API AtomicFlag
|
|
/// This class implements an atomic boolean flag by wrapping
|
|
/// the std::atomic_flag. It is guaranteed to be thread-safe
|
|
/// and lock-free.
|
|
///
|
|
/// Only default-construction is allowed, objects of this
|
|
/// class are not copyable, assignable or movable.
|
|
///
|
|
/// Note that this class is not a replacement for (atomic)
|
|
/// bool type because its value can not be read without also
|
|
/// being set to true. However, after being set (either
|
|
/// explicitly, through the set() call or implicitly, via
|
|
/// operator bool()), it can be reset and reused.
|
|
///
|
|
/// The class is useful in scenarios such as busy-wait or
|
|
/// one-off code blocks, e.g.:
|
|
///
|
|
/// class MyClass
|
|
/// {
|
|
/// public:
|
|
/// void myFunc()
|
|
/// {
|
|
/// if (!_beenHere) doOnce();
|
|
/// doMany();
|
|
/// }
|
|
///
|
|
/// void doOnce() { /* executed once */ }
|
|
///
|
|
/// void doMany() { /* executed multiple times */ }
|
|
///
|
|
/// private:
|
|
/// AtomicFlag _beenHere;
|
|
/// }
|
|
///
|
|
/// MyClass myClass;
|
|
/// int i = 0;
|
|
/// while (++i < 10) myClass.myFunc();
|
|
{
|
|
public:
|
|
AtomicFlag() = default;
|
|
/// Creates AtomicFlag.
|
|
|
|
~AtomicFlag() = default;
|
|
/// Destroys AtomicFlag.
|
|
|
|
bool set();
|
|
/// Sets the flag to true and returns previously
|
|
/// held value.
|
|
|
|
void reset();
|
|
/// Resets the flag to false.
|
|
|
|
operator bool ();
|
|
/// Sets the flag to true and returns previously
|
|
/// held value.
|
|
|
|
private:
|
|
AtomicFlag(const AtomicFlag&) = delete;
|
|
AtomicFlag& operator = (const AtomicFlag&) = delete;
|
|
AtomicFlag(AtomicFlag&&) = delete;
|
|
AtomicFlag& operator = (AtomicFlag&&) = delete;
|
|
|
|
std::atomic_flag _flag = ATOMIC_FLAG_INIT;
|
|
};
|
|
|
|
|
|
//
|
|
// inlines
|
|
//
|
|
|
|
|
|
inline bool AtomicFlag::set()
|
|
{
|
|
return _flag.test_and_set(std::memory_order_acquire);
|
|
}
|
|
|
|
|
|
inline void AtomicFlag::reset()
|
|
{
|
|
_flag.clear(std::memory_order_release);
|
|
}
|
|
|
|
|
|
inline AtomicFlag::operator bool ()
|
|
{
|
|
return set();
|
|
}
|
|
|
|
|
|
} // namespace Poco
|
|
|
|
|
|
#endif // Foundation_AtomicFlag_INCLUDED
|
|
|