/*

 * Copyright © 2007  Chris Wilson

 * Copyright © 2009,2010  Red Hat, Inc.

 * Copyright © 2011,2012  Google, Inc.

 *

 *  This is part of HarfBuzz, a text shaping library.

 *

 * Permission is hereby granted, without written agreement and without

 * license or royalty fees, to use, copy, modify, and distribute this

 * software and its documentation for any purpose, provided that the

 * above copyright notice and the following two paragraphs appear in

 * all copies of this software.

 *

 * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR

 * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES

 * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN

 * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH

 * DAMAGE.

 *

 * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,

 * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND

 * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS

 * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO

 * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.

 *

 * Contributor(s):

 *      Chris Wilson <chris@chris-wilson.co.uk>

 * Red Hat Author(s): Behdad Esfahbod

 * Google Author(s): Behdad Esfahbod

 */

#ifndef HB_MUTEX_PRIVATE_HH

#define HB_MUTEX_PRIVATE_HH

#include "hb-private.hh"

/* mutex */

/* We need external help for these */

#if defined(HB_MUTEX_IMPL_INIT) \

 && defined(hb_mutex_impl_init) \

 && defined(hb_mutex_impl_lock) \

 && defined(hb_mutex_impl_unlock) \

 && defined(hb_mutex_impl_finish)

/* Defined externally, i.e. in config.h; must have typedef'ed hb_mutex_impl_t as well. */

#elif !defined(HB_NO_MT) && (defined(_WIN32) || defined(__CYGWIN__))

#include <windows.h>

typedef CRITICAL_SECTION hb_mutex_impl_t;

#define HB_MUTEX_IMPL_INIT      {0}

#if defined(WINAPI_FAMILY) && (WINAPI_FAMILY==WINAPI_FAMILY_PC_APP || WINAPI_FAMILY==WINAPI_FAMILY_PHONE_APP)

#define hb_mutex_impl_init(M)   InitializeCriticalSectionEx (M, 0, 0)

#else

#define hb_mutex_impl_init(M)   InitializeCriticalSection (M)

#endif

#define hb_mutex_impl_lock(M)   EnterCriticalSection (M)

#define hb_mutex_impl_unlock(M) LeaveCriticalSection (M)

#define hb_mutex_impl_finish(M) DeleteCriticalSection (M)

#elif !defined(HB_NO_MT) && (defined(HAVE_PTHREAD) || defined(__APPLE__))

#include <pthread.h>

typedef pthread_mutex_t hb_mutex_impl_t;

#define HB_MUTEX_IMPL_INIT      PTHREAD_MUTEX_INITIALIZER

#define hb_mutex_impl_init(M)   pthread_mutex_init (M, nullptr)

#define hb_mutex_impl_lock(M)   pthread_mutex_lock (M)

#define hb_mutex_impl_unlock(M) pthread_mutex_unlock (M)

#define hb_mutex_impl_finish(M) pthread_mutex_destroy (M)

#elif !defined(HB_NO_MT) && defined(HAVE_INTEL_ATOMIC_PRIMITIVES)

#if defined(HAVE_SCHED_H) && defined(HAVE_SCHED_YIELD)

# include <sched.h>

# define HB_SCHED_YIELD() sched_yield ()

#else

# define HB_SCHED_YIELD() HB_STMT_START {} HB_STMT_END

#endif

/* This actually is not a totally awful implementation. */

typedef volatile int hb_mutex_impl_t;

#define HB_MUTEX_IMPL_INIT      0

#define hb_mutex_impl_init(M)   *(M) = 0

#define hb_mutex_impl_lock(M)   HB_STMT_START { while (__sync_lock_test_and_set((M), 1)) HB_SCHED_YIELD (); } HB_STMT_END

#define hb_mutex_impl_unlock(M) __sync_lock_release (M)

#define hb_mutex_impl_finish(M) HB_STMT_START {} HB_STMT_END

#elif !defined(HB_NO_MT)

#if defined(HAVE_SCHED_H) && defined(HAVE_SCHED_YIELD)

# include <sched.h>

# define HB_SCHED_YIELD() sched_yield ()

#else

# define HB_SCHED_YIELD() HB_STMT_START {} HB_STMT_END

#endif

#define HB_MUTEX_INT_NIL 1 /* Warn that fallback implementation is in use. */

typedef volatile int hb_mutex_impl_t;

#define HB_MUTEX_IMPL_INIT      0

#define hb_mutex_impl_init(M)   *(M) = 0

#define hb_mutex_impl_lock(M)   HB_STMT_START { while (*(M)) HB_SCHED_YIELD (); (*(M))++; } HB_STMT_END

#define hb_mutex_impl_unlock(M) (*(M))--;

#define hb_mutex_impl_finish(M) HB_STMT_START {} HB_STMT_END

#else /* HB_NO_MT */

typedef int hb_mutex_impl_t;

#define HB_MUTEX_IMPL_INIT      0

#define hb_mutex_impl_init(M)   HB_STMT_START {} HB_STMT_END

#define hb_mutex_impl_lock(M)   HB_STMT_START {} HB_STMT_END

#define hb_mutex_impl_unlock(M) HB_STMT_START {} HB_STMT_END

#define hb_mutex_impl_finish(M) HB_STMT_START {} HB_STMT_END

#endif

#define HB_MUTEX_INIT           {HB_MUTEX_IMPL_INIT}

struct hb_mutex_t

{

  /* TODO Add tracing. */

  hb_mutex_impl_t m;

  inline void init   (void) { hb_mutex_impl_init   (&m); }

  inline void lock   (void) { hb_mutex_impl_lock   (&m); }

  inline void unlock (void) { hb_mutex_impl_unlock (&m); }

};

#endif /* HB_MUTEX_PRIVATE_HH */