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/*
* Copyright (C) 2020 Linux Studio Plugins Project <https://lsp-plug.in/>
* (C) 2020 Vladimir Sadovnikov <sadko4u@gmail.com>
*
* This file is part of lsp-runtime-lib
* Created on: 25 февр. 2019 г.
*
* lsp-runtime-lib is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* any later version.
*
* lsp-runtime-lib is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with lsp-runtime-lib. If not, see <https://www.gnu.org/licenses/>.
*/
#ifndef LSP_PLUG_IN_IPC_MUTEX_H_
#define LSP_PLUG_IN_IPC_MUTEX_H_
#include <lsp-plug.in/runtime/version.h>
#include <lsp-plug.in/common/types.h>
#include <lsp-plug.in/common/atomic.h>
#if defined(PLATFORM_WINDOWS)
#include <synchapi.h>
#elif defined(PLATFORM_LINUX)
#include <linux/futex.h>
#include <sys/syscall.h>
#include <unistd.h>
#include <pthread.h>
#include <sched.h>
#include <errno.h>
#else
#include <pthread.h>
#include <sched.h>
#include <errno.h>
#endif
namespace lsp
{
namespace ipc
{
#if defined(PLATFORM_WINDOWS)
/**
* Recursive mutex for Windows platform
*/
class Mutex
{
private:
mutable HANDLE hMutex; // Mutex object
mutable DWORD nThreadId; // Owner's thread identifier
mutable atomic_t nLocks; // Number of locks by current thread
private:
Mutex & operator = (const Mutex & m); // Deny copying
public:
explicit Mutex();
~Mutex();
/** Wait until mutex is unlocked and lock it
*
*/
bool lock() const;
/** Try to lock mutex and return status of operation
*
* @return non-zero value if mutex was locked
*/
bool try_lock() const;
/** Unlock mutex
*
*/
bool unlock() const;
};
#elif defined(PLATFORM_LINUX)
/** Fast recursive mutex implementation for Linux
*
*/
class Mutex
{
private:
mutable volatile atomic_t nLock; // 1 = unlocked, 0 = locked
mutable pthread_t nThreadId; // Locked thread identifier
mutable atomic_t nLocks; // Number of locks by current thread
private:
Mutex & operator = (const Mutex & m); // Deny copying
public:
explicit Mutex()
{
nLock = 1;
nThreadId = -1;
nLocks = 0;
}
/** Wait until mutex is unlocked and lock it
*
*/
bool lock() const;
/** Try to lock mutex and return status of operation
*
* @return non-zero value if mutex was locked
*/
bool try_lock() const;
/** Unlock mutex
*
*/
bool unlock() const;
};
#else
/**
* Recursive mutex implementation using pthread
*/
class Mutex
{
private:
mutable pthread_mutex_t sMutex;
private:
Mutex & operator = (const Mutex & m); // Deny copying
public:
explicit Mutex();
~Mutex();
/** Wait until mutex is unlocked and lock it
*
*/
inline bool lock() const
{
while (true)
{
switch (pthread_mutex_lock(&sMutex))
{
case 0: return true;
case EBUSY:
sched_yield();
break;
default: return false;
}
}
}
/** Try to lock mutex and return status of operation
*
* @return non-zero value if mutex was locked
*/
inline bool try_lock() const
{
return pthread_mutex_trylock(&sMutex) == 0;
}
/** Unlock mutex
*
*/
inline bool unlock() const
{
return pthread_mutex_unlock(&sMutex) == 0;
}
};
#endif
} /* namespace ipc */
} /* namespace lsp */
#endif /* LSP_PLUG_IN_IPC_MUTEX_H_ */
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