mirror of
https://github.com/ClickHouse/ClickHouse.git
synced 2024-12-04 05:22:17 +00:00
140 lines
3.4 KiB
C++
140 lines
3.4 KiB
C++
//
|
|
// Semaphore.h
|
|
//
|
|
// $Id: //poco/1.4/Foundation/include/Poco/Semaphore.h#2 $
|
|
//
|
|
// Library: Foundation
|
|
// Package: Threading
|
|
// Module: Semaphore
|
|
//
|
|
// Definition of the Semaphore class.
|
|
//
|
|
// Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH.
|
|
// and Contributors.
|
|
//
|
|
// SPDX-License-Identifier: BSL-1.0
|
|
//
|
|
|
|
|
|
#ifndef Foundation_Semaphore_INCLUDED
|
|
#define Foundation_Semaphore_INCLUDED
|
|
|
|
|
|
#include "Poco/Foundation.h"
|
|
#include "Poco/Exception.h"
|
|
|
|
|
|
#if defined(POCO_OS_FAMILY_WINDOWS)
|
|
#include "Poco/Semaphore_WIN32.h"
|
|
#elif defined(POCO_VXWORKS)
|
|
#include "Poco/Semaphore_VX.h"
|
|
#else
|
|
#include "Poco/Semaphore_POSIX.h"
|
|
#endif
|
|
|
|
|
|
namespace Poco {
|
|
|
|
|
|
class Foundation_API Semaphore: private SemaphoreImpl
|
|
/// A Semaphore is a synchronization object with the following
|
|
/// characteristics:
|
|
/// A semaphore has a value that is constrained to be a non-negative
|
|
/// integer and two atomic operations. The allowable operations are V
|
|
/// (here called set()) and P (here called wait()). A V (set()) operation
|
|
/// increases the value of the semaphore by one.
|
|
/// A P (wait()) operation decreases the value of the semaphore by one,
|
|
/// provided that can be done without violating the constraint that the
|
|
/// value be non-negative. A P (wait()) operation that is initiated when
|
|
/// the value of the semaphore is 0 suspends the calling thread.
|
|
/// The calling thread may continue when the value becomes positive again.
|
|
{
|
|
public:
|
|
Semaphore(int n);
|
|
Semaphore(int n, int max);
|
|
/// Creates the semaphore. The current value
|
|
/// of the semaphore is given in n. The
|
|
/// maximum value of the semaphore is given
|
|
/// in max.
|
|
/// If only n is given, it must be greater than
|
|
/// zero.
|
|
/// If both n and max are given, max must be
|
|
/// greater than zero, n must be greater than
|
|
/// or equal to zero and less than or equal
|
|
/// to max.
|
|
|
|
~Semaphore();
|
|
/// Destroys the semaphore.
|
|
|
|
void set();
|
|
/// Increments the semaphore's value by one and
|
|
/// thus signals the semaphore. Another thread
|
|
/// waiting for the semaphore will be able
|
|
/// to continue.
|
|
|
|
void wait();
|
|
/// Waits for the semaphore to become signalled.
|
|
/// To become signalled, a semaphore's value must
|
|
/// be greater than zero.
|
|
/// Decrements the semaphore's value by one.
|
|
|
|
void wait(long milliseconds);
|
|
/// Waits for the semaphore to become signalled.
|
|
/// To become signalled, a semaphore's value must
|
|
/// be greater than zero.
|
|
/// Throws a TimeoutException if the semaphore
|
|
/// does not become signalled within the specified
|
|
/// time interval.
|
|
/// Decrements the semaphore's value by one
|
|
/// if successful.
|
|
|
|
bool tryWait(long milliseconds);
|
|
/// Waits for the semaphore to become signalled.
|
|
/// To become signalled, a semaphore's value must
|
|
/// be greater than zero.
|
|
/// Returns true if the semaphore
|
|
/// became signalled within the specified
|
|
/// time interval, false otherwise.
|
|
/// Decrements the semaphore's value by one
|
|
/// if successful.
|
|
|
|
private:
|
|
Semaphore();
|
|
Semaphore(const Semaphore&);
|
|
Semaphore& operator = (const Semaphore&);
|
|
};
|
|
|
|
|
|
//
|
|
// inlines
|
|
//
|
|
inline void Semaphore::set()
|
|
{
|
|
setImpl();
|
|
}
|
|
|
|
|
|
inline void Semaphore::wait()
|
|
{
|
|
waitImpl();
|
|
}
|
|
|
|
|
|
inline void Semaphore::wait(long milliseconds)
|
|
{
|
|
if (!waitImpl(milliseconds))
|
|
throw TimeoutException();
|
|
}
|
|
|
|
|
|
inline bool Semaphore::tryWait(long milliseconds)
|
|
{
|
|
return waitImpl(milliseconds);
|
|
}
|
|
|
|
|
|
} // namespace Poco
|
|
|
|
|
|
#endif // Foundation_Semaphore_INCLUDED
|