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/*
This file is part of libmicrohttpd
Copyright (C) 2016 Karlson2k (Evgeny Grin)
This library 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 2.1 of the License, or (at your option) any later version.
This library 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 this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file microhttpd/mhd_locks.h
* @brief Header for platform-independent locks abstraction
* @author Karlson2k (Evgeny Grin)
* @author Christian Grothoff
*
* Provides basic abstraction for locks/mutex and semaphores.
* Any functions can be implemented as macro on some platforms
* unless explicitly marked otherwise.
* Any function argument can be skipped in macro, so avoid
* variable modification in function parameters.
*
* @warning Unlike pthread functions, most of functions return
* nonzero on success.
*/
#ifndef MHD_LOCKS_H
#define MHD_LOCKS_H 1
#include "mhd_options.h"
#if defined(MHD_USE_W32_THREADS)
# define MHD_W32_MUTEX_ 1
# ifndef WIN32_LEAN_AND_MEAN
# define WIN32_LEAN_AND_MEAN 1
# endif /* !WIN32_LEAN_AND_MEAN */
# include <windows.h>
#elif defined(HAVE_PTHREAD_H) && defined(MHD_USE_POSIX_THREADS)
# define MHD_PTHREAD_MUTEX_ 1
# undef HAVE_CONFIG_H
# include <pthread.h>
# define HAVE_CONFIG_H 1
#else
# error No base mutex API is available.
#endif
#if defined(MHD_PTHREAD_MUTEX_)
typedef pthread_mutex_t MHD_mutex_;
#elif defined(MHD_W32_MUTEX_)
typedef CRITICAL_SECTION MHD_mutex_;
#endif
#if defined(MHD_PTHREAD_MUTEX_)
/**
* Initialise new mutex.
* @param pmutex pointer to the mutex
* @return nonzero on success, zero otherwise
*/
#define MHD_mutex_init_(pmutex) (!(pthread_mutex_init((pmutex), NULL)))
#elif defined(MHD_W32_MUTEX_)
/**
* Initialise new mutex.
* @param pmutex pointer to mutex
* @return nonzero on success, zero otherwise
*/
#define MHD_mutex_init_(pmutex) (InitializeCriticalSectionAndSpinCount((pmutex),16))
#endif
#if defined(MHD_PTHREAD_MUTEX_)
/**
* Destroy previously initialised mutex.
* @param pmutex pointer to mutex
* @return nonzero on success, zero otherwise
*/
#define MHD_mutex_destroy_(pmutex) (!(pthread_mutex_destroy((pmutex))))
#elif defined(MHD_W32_MUTEX_)
/**
* Destroy previously initialised mutex.
* @param pmutex pointer to mutex
* @return Always nonzero
*/
#define MHD_mutex_destroy_(pmutex) (DeleteCriticalSection((pmutex)), !0)
#endif
#if defined(MHD_PTHREAD_MUTEX_)
/**
* Acquire lock on previously initialised mutex.
* If mutex was already locked by other thread, function
* blocks until mutex becomes available.
* @param pmutex pointer to mutex
* @return nonzero on success, zero otherwise
*/
#define MHD_mutex_lock_(pmutex) (!(pthread_mutex_lock((pmutex))))
#elif defined(MHD_W32_MUTEX_)
/**
* Acquire lock on previously initialised mutex.
* If mutex was already locked by other thread, function
* blocks until mutex becomes available.
* @param pmutex pointer to mutex
* @return Always nonzero
*/
#define MHD_mutex_lock_(pmutex) (EnterCriticalSection((pmutex)), !0)
#endif
#if defined(MHD_PTHREAD_MUTEX_)
/**
* Try to acquire lock on previously initialised mutex.
* Function returns immediately.
* @param pmutex pointer to mutex
* @return nonzero if mutex is locked, zero if
* mutex was not locked.
*/
#define MHD_mutex_trylock_(pmutex) (!(pthread_mutex_trylock((pmutex))))
#elif defined(MHD_W32_MUTEX_)
/**
* Try to acquire lock on previously initialised mutex.
* Function returns immediately.
* @param pmutex pointer to mutex
* @return nonzero if mutex is locked, zero if
* mutex was not locked.
*/
#define MHD_mutex_trylock_(pmutex) (TryEnterCriticalSection((pmutex))))
#endif
#if defined(MHD_PTHREAD_MUTEX_)
/**
* Unlock previously initialised and locked mutex.
* @param pmutex pointer to mutex
* @return nonzero on success, zero otherwise
*/
#define MHD_mutex_unlock_(pmutex) (!(pthread_mutex_unlock((pmutex))))
#elif defined(MHD_W32_MUTEX_)
/**
* Unlock previously initialised and locked mutex.
* @param pmutex pointer to mutex
* @return Always nonzero
*/
#define MHD_mutex_unlock_(pmutex) (LeaveCriticalSection((pmutex)), !0)
#endif
/**
* A semaphore.
*/
struct MHD_Semaphore;
/**
* Create a semaphore with an initial counter of @a init
*
* @param init initial counter
* @return the semaphore, NULL on error
*/
struct MHD_Semaphore *
MHD_semaphore_create (unsigned int init);
/**
* Count down the semaphore, block if necessary.
*
* @param sem semaphore to count down.
*/
void
MHD_semaphore_down (struct MHD_Semaphore *sem);
/**
* Increment the semaphore.
*
* @param sem semaphore to increment.
*/
void
MHD_semaphore_up (struct MHD_Semaphore *sem);
/**
* Destroys the semaphore.
*
* @param sem semaphore to destroy.
*/
void
MHD_semaphore_destroy (struct MHD_Semaphore *sem);
#endif /* ! MHD_LOCKS_H */
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