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path: root/libs/cairo/src/cairo-mutex-impl-private.h
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/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef CAIRO_MUTEX_IMPL_PRIVATE_H
#define CAIRO_MUTEX_IMPL_PRIVATE_H

#include "cairo.h"

#if HAVE_CONFIG_H
#include "config.h"
#endif

#if HAVE_LOCKDEP
#include <lockdep.h>
#endif

/* A fully qualified no-operation statement */
#define CAIRO_MUTEX_IMPL_NOOP	do {/*no-op*/} while (0)
/* And one that evaluates its argument once */
#define CAIRO_MUTEX_IMPL_NOOP1(expr)        do { (void)(expr); } while (0)
/* Note: 'if (expr) {}' is an alternative to '(void)(expr);' that will 'use' the
 * result of __attribute__((warn_used_result)) functions. */

/* Cairo mutex implementation:
 *
 * Any new mutex implementation needs to do the following:
 *
 * - Condition on the right header or feature.  Headers are
 *   preferred as eg. you still can use win32 mutex implementation
 *   on a win32 system even if you do not compile the win32
 *   surface/backend.
 *
 * - typedef #cairo_mutex_impl_t to the proper mutex type on your target
 *   system.  Note that you may or may not need to use a pointer,
 *   depending on what kinds of initialization your mutex
 *   implementation supports.  No trailing semicolon needed.
 *   You should be able to compile the following snippet (don't try
 *   running it):
 *
 *   <programlisting>
 *	cairo_mutex_impl_t _cairo_some_mutex;
 *   </programlisting>
 *
 * - #define %CAIRO_MUTEX_IMPL_<NAME> 1 with suitable name for your platform.  You
 *   can later use this symbol in cairo-system.c.
 *
 * - #define CAIRO_MUTEX_IMPL_LOCK(mutex) and CAIRO_MUTEX_IMPL_UNLOCK(mutex) to
 *   proper statement to lock/unlock the mutex object passed in.
 *   You can (and should) assume that the mutex is already
 *   initialized, and is-not-already-locked/is-locked,
 *   respectively.  Use the "do { ... } while (0)" idiom if necessary.
 *   No trailing semicolons are needed (in any macro you define here).
 *   You should be able to compile the following snippet:
 *
 *   <programlisting>
 *	cairo_mutex_impl_t _cairo_some_mutex;
 *
 *      if (1)
 *          CAIRO_MUTEX_IMPL_LOCK (_cairo_some_mutex);
 *      else
 *          CAIRO_MUTEX_IMPL_UNLOCK (_cairo_some_mutex);
 *   </programlisting>
 *
 * - #define %CAIRO_MUTEX_IMPL_NIL_INITIALIZER to something that can
 *   initialize the #cairo_mutex_impl_t type you defined.  Most of the
 *   time one of 0, %NULL, or {} works.  At this point
 *   you should be able to compile the following snippet:
 *
 *   <programlisting>
 *	cairo_mutex_impl_t _cairo_some_mutex = CAIRO_MUTEX_IMPL_NIL_INITIALIZER;
 *
 *      if (1)
 *          CAIRO_MUTEX_IMPL_LOCK (_cairo_some_mutex);
 *      else
 *          CAIRO_MUTEX_IMPL_UNLOCK (_cairo_some_mutex);
 *   </programlisting>
 *
 * - If the above code is not enough to initialize a mutex on
 *   your platform, #define CAIRO_MUTEX_IMPL_INIT(mutex) to statement
 *   to initialize the mutex (allocate resources, etc).  Such that
 *   you should be able to compile AND RUN the following snippet:
 *
 *   <programlisting>
 *	cairo_mutex_impl_t _cairo_some_mutex = CAIRO_MUTEX_IMPL_NIL_INITIALIZER;
 *
 *      CAIRO_MUTEX_IMPL_INIT (_cairo_some_mutex);
 *
 *      if (1)
 *          CAIRO_MUTEX_IMPL_LOCK (_cairo_some_mutex);
 *      else
 *          CAIRO_MUTEX_IMPL_UNLOCK (_cairo_some_mutex);
 *   </programlisting>
 *
 * - If you define CAIRO_MUTEX_IMPL_INIT(mutex), cairo will use it to
 *   initialize all static mutex'es.  If for any reason that should
 *   not happen (eg. %CAIRO_MUTEX_IMPL_INIT is just a faster way than
 *   what cairo does using %CAIRO_MUTEX_IMPL_NIL_INITIALIZER), then
 *   <programlisting>
 *      #define CAIRO_MUTEX_IMPL_INITIALIZE() CAIRO_MUTEX_IMPL_NOOP
 *   </programlisting>
 *
 * - If your system supports freeing a mutex object (deallocating
 *   resources, etc), then #define CAIRO_MUTEX_IMPL_FINI(mutex) to do
 *   that.
 *
 * - If you define CAIRO_MUTEX_IMPL_FINI(mutex), cairo will use it to
 *   define a finalizer function to finalize all static mutex'es.
 *   However, it's up to you to call CAIRO_MUTEX_IMPL_FINALIZE() at
 *   proper places, eg. when the system is unloading the cairo library.
 *   So, if for any reason finalizing static mutex'es is not needed
 *   (eg. you never call CAIRO_MUTEX_IMPL_FINALIZE()), then
 *   <programlisting>
 *      #define CAIRO_MUTEX_IMPL_FINALIZE() CAIRO_MUTEX_IMPL_NOOP
 *   </programlisting>
 *
 * - That is all.  If for any reason you think the above API is
 *   not enough to implement #cairo_mutex_impl_t on your system, please
 *   stop and write to the cairo mailing list about it.  DO NOT
 *   poke around cairo-mutex-private.h for possible solutions.
 */

#if CAIRO_NO_MUTEX

/* No mutexes */

  typedef int cairo_mutex_impl_t;

# define CAIRO_MUTEX_IMPL_NO 1
# define CAIRO_MUTEX_IMPL_INITIALIZE() CAIRO_MUTEX_IMPL_NOOP
# define CAIRO_MUTEX_IMPL_LOCK(mutex) CAIRO_MUTEX_IMPL_NOOP1(mutex)
# define CAIRO_MUTEX_IMPL_UNLOCK(mutex) CAIRO_MUTEX_IMPL_NOOP1(mutex)
# define CAIRO_MUTEX_IMPL_NIL_INITIALIZER 0

# define CAIRO_MUTEX_HAS_RECURSIVE_IMPL 1

  typedef int cairo_recursive_mutex_impl_t;

# define CAIRO_RECURSIVE_MUTEX_IMPL_INIT(mutex)
# define CAIRO_RECURSIVE_MUTEX_IMPL_NIL_INITIALIZER 0

#elif defined(_WIN32) /******************************************************/

#ifndef WIN32_LEAN_AND_MEAN
# define WIN32_LEAN_AND_MEAN
#endif
/* We require Windows 7 features */
#if !defined(WINVER) || (WINVER < 0x0601)
# define WINVER 0x0601
#endif
#if !defined(_WIN32_WINNT) || (_WIN32_WINNT < 0x0601)
# define _WIN32_WINNT 0x0601
#endif

# include <windows.h>

  typedef SRWLOCK cairo_mutex_impl_t;

# define CAIRO_MUTEX_IMPL_WIN32 1
# define CAIRO_MUTEX_IMPL_LOCK(mutex) AcquireSRWLockExclusive (&(mutex))
# define CAIRO_MUTEX_IMPL_UNLOCK(mutex) ReleaseSRWLockExclusive (&(mutex))
# define CAIRO_MUTEX_IMPL_INIT(mutex) InitializeSRWLock (&(mutex))
# define CAIRO_MUTEX_IMPL_FINI(mutex) CAIRO_MUTEX_IMPL_NOOP
# define CAIRO_MUTEX_IMPL_NIL_INITIALIZER SRWLOCK_INIT

#elif defined __OS2__ /******************************************************/

# define INCL_BASE
# define INCL_PM
# include <os2.h>

  typedef HMTX cairo_mutex_impl_t;

# define CAIRO_MUTEX_IMPL_OS2 1
# define CAIRO_MUTEX_IMPL_LOCK(mutex) DosRequestMutexSem(mutex, SEM_INDEFINITE_WAIT)
# define CAIRO_MUTEX_IMPL_UNLOCK(mutex) DosReleaseMutexSem(mutex)
# define CAIRO_MUTEX_IMPL_INIT(mutex) DosCreateMutexSem (NULL, &(mutex), 0L, FALSE)
# define CAIRO_MUTEX_IMPL_FINI(mutex) DosCloseMutexSem (mutex)
# define CAIRO_MUTEX_IMPL_NIL_INITIALIZER 0

#elif CAIRO_HAS_BEOS_SURFACE /***********************************************/

  typedef BLocker* cairo_mutex_impl_t;

# define CAIRO_MUTEX_IMPL_BEOS 1
# define CAIRO_MUTEX_IMPL_LOCK(mutex) (mutex)->Lock()
# define CAIRO_MUTEX_IMPL_UNLOCK(mutex) (mutex)->Unlock()
# define CAIRO_MUTEX_IMPL_INIT(mutex) (mutex) = new BLocker()
# define CAIRO_MUTEX_IMPL_FINI(mutex) delete (mutex)
# define CAIRO_MUTEX_IMPL_NIL_INITIALIZER NULL

#elif CAIRO_HAS_PTHREAD /* and finally if there are no native mutexes ********/

# include <pthread.h>

  typedef pthread_mutex_t cairo_mutex_impl_t;
  typedef pthread_mutex_t cairo_recursive_mutex_impl_t;

# define CAIRO_MUTEX_IMPL_PTHREAD 1
#if HAVE_LOCKDEP
/* expose all mutexes to the validator */
# define CAIRO_MUTEX_IMPL_INIT(mutex) pthread_mutex_init (&(mutex), NULL)
#endif
# define CAIRO_MUTEX_IMPL_LOCK(mutex) pthread_mutex_lock (&(mutex))
# define CAIRO_MUTEX_IMPL_UNLOCK(mutex) pthread_mutex_unlock (&(mutex))
#if HAVE_LOCKDEP
# define CAIRO_MUTEX_IS_LOCKED(mutex) LOCKDEP_IS_LOCKED (&(mutex))
# define CAIRO_MUTEX_IS_UNLOCKED(mutex) LOCKDEP_IS_UNLOCKED (&(mutex))
#endif
# define CAIRO_MUTEX_IMPL_FINI(mutex) pthread_mutex_destroy (&(mutex))
#if ! HAVE_LOCKDEP
# define CAIRO_MUTEX_IMPL_FINALIZE() CAIRO_MUTEX_IMPL_NOOP
#endif
# define CAIRO_MUTEX_IMPL_NIL_INITIALIZER PTHREAD_MUTEX_INITIALIZER

# define CAIRO_MUTEX_HAS_RECURSIVE_IMPL 1
# define CAIRO_RECURSIVE_MUTEX_IMPL_INIT(mutex) do { \
    pthread_mutexattr_t attr; \
    pthread_mutexattr_init (&attr); \
    pthread_mutexattr_settype (&attr, PTHREAD_MUTEX_RECURSIVE); \
    pthread_mutex_init (&(mutex), &attr); \
    pthread_mutexattr_destroy (&attr); \
} while (0)
# define CAIRO_RECURSIVE_MUTEX_IMPL_NIL_INITIALIZER PTHREAD_RECURSIVE_MUTEX_INITIALIZER_NP

#else /**********************************************************************/

# error "XXX: No mutex implementation found.  Cairo will not work with multiple threads.  Define CAIRO_NO_MUTEX to 1 to acknowledge and accept this limitation and compile cairo without thread-safety support."

#endif

/* By default mutex implementations are assumed to be recursive */
#if ! CAIRO_MUTEX_HAS_RECURSIVE_IMPL

# define CAIRO_MUTEX_HAS_RECURSIVE_IMPL 1

  typedef cairo_mutex_impl_t cairo_recursive_mutex_impl_t;

# define CAIRO_RECURSIVE_MUTEX_IMPL_INIT(mutex) CAIRO_MUTEX_IMPL_INIT(mutex)
# define CAIRO_RECURSIVE_MUTEX_IMPL_NIL_INITIALIZER CAIRO_MUTEX_IMPL_NIL_INITIALIZER

#endif

#endif