ClickHouse/contrib/libpoco/Foundation/include/Poco/NamedMutex.h

115 lines
2.5 KiB
C++

//
// NamedMutex.h
//
// $Id: //poco/1.4/Foundation/include/Poco/NamedMutex.h#2 $
//
// Library: Foundation
// Package: Processes
// Module: NamedMutex
//
// Definition of the NamedMutex class.
//
// Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// SPDX-License-Identifier: BSL-1.0
//
#ifndef Foundation_NamedMutex_INCLUDED
#define Foundation_NamedMutex_INCLUDED
#include "Poco/Foundation.h"
#include "Poco/ScopedLock.h"
#if defined(POCO_OS_FAMILY_WINDOWS) && defined(POCO_WIN32_UTF8)
#include "Poco/NamedMutex_WIN32U.h"
#elif defined(POCO_OS_FAMILY_WINDOWS)
#include "Poco/NamedMutex_WIN32.h"
#elif defined(POCO_ANDROID)
#include "Poco/NamedMutex_Android.h"
#elif defined(POCO_OS_FAMILY_UNIX)
#include "Poco/NamedMutex_UNIX.h"
#else
#include "Poco/NamedMutex_VMS.h"
#endif
namespace Poco {
class Foundation_API NamedMutex: private NamedMutexImpl
/// A NamedMutex (mutual exclusion) is a global synchronization
/// mechanism used to control access to a shared resource
/// in a concurrent (multi process) scenario.
/// Using the ScopedLock class is the preferred way to automatically
/// lock and unlock a mutex.
///
/// Unlike a Mutex or a FastMutex, which itself is the unit of synchronization,
/// a NamedMutex refers to a named operating system resource being the
/// unit of synchronization.
/// In other words, there can be multiple instances of NamedMutex referring
/// to the same actual synchronization object.
///
///
/// There should not be more than one instance of NamedMutex for
/// a given name in a process. Otherwise, the instances may
/// interfere with each other.
{
public:
typedef Poco::ScopedLock<NamedMutex> ScopedLock;
NamedMutex(const std::string& name);
/// creates the Mutex.
~NamedMutex();
/// destroys the Mutex.
void lock();
/// Locks the mutex. Blocks if the mutex
/// is held by another process or thread.
bool tryLock();
/// Tries to lock the mutex. Returns false immediately
/// if the mutex is already held by another process or thread.
/// Returns true if the mutex was successfully locked.
void unlock();
/// Unlocks the mutex so that it can be acquired by
/// other threads.
private:
NamedMutex();
NamedMutex(const NamedMutex&);
NamedMutex& operator = (const NamedMutex&);
};
//
// inlines
//
inline void NamedMutex::lock()
{
lockImpl();
}
inline bool NamedMutex::tryLock()
{
return tryLockImpl();
}
inline void NamedMutex::unlock()
{
unlockImpl();
}
} // namespace Poco
#endif // Foundation_NamedMutex_INCLUDED