/*

  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.

 * 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

#ifndef MHD_PANIC

#  include <stdio.h>

#  include <stdlib.h>

/* Simple implementation of MHD_PANIC, to be used outside lib */

#  define MHD_PANIC(msg) do { fprintf (stderr,           \

     "Abnormal termination at %d line in file %s: %s\n", \

     (int)__LINE__, __FILE__, msg); abort();} while(0)

#endif /* ! MHD_PANIC */

#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_)

#  if defined(PTHREAD_MUTEX_INITIALIZER)

/**

 *  Define static mutex and statically initialise it.

 */

#    define MHD_MUTEX_STATIC_DEFN_INIT_(m) static MHD_mutex_ m = PTHREAD_MUTEX_INITIALIZER

#  endif /* PTHREAD_MUTEX_INITIALIZER */

#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

/**

 * Destroy previously initialised mutex and abort execution

 * if error is detected.

 * @param pmutex pointer to mutex

 */

#define MHD_mutex_destroy_chk_(pmutex) do {       \

    if (!MHD_mutex_destroy_(pmutex))              \

      MHD_PANIC(_("Failed to destroy mutex.\n")); \

  } while(0)

#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

/**

 * Acquire lock on previously initialised mutex.

 * If mutex was already locked by other thread, function

 * blocks until mutex becomes available.

 * If error is detected, execution will be aborted.

 * @param pmutex pointer to mutex

 */

#define MHD_mutex_lock_chk_(pmutex) do {       \

    if (!MHD_mutex_lock_(pmutex))              \

      MHD_PANIC(_("Failed to lock mutex.\n")); \

  } while(0)

#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

/**

 * Unlock previously initialised and locked mutex.

 * If error is detected, execution will be aborted.

 * @param pmutex pointer to mutex

 */

#define MHD_mutex_unlock_chk_(pmutex) do {       \

    if (!MHD_mutex_unlock_(pmutex))              \

      MHD_PANIC(_("Failed to unlock mutex.\n")); \

  } while(0)

#endif /* ! MHD_LOCKS_H */