LUMIERA.clone/src/lib/rwlock.h

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2007-09-03 06:35:13 +02:00
/*
rwlock.h - read/write locks
Copyright (C) CinelerraCV
2007, Christian Thaeter <ct@pipapo.org>
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.
This program 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#ifndef CINELERRA_RWLOCK_H
#define CINELERRA_RWLOCK_H
#ifndef _GNU_SOURCE
#error "This header must be included with _GNU_SOURCE or _POSIX_C_SOURCE >= 200112L defined"
#endif
#include <pthread.h>
#include <nobug.h>
#include "lib/locking.h"
CINELERRA_ERROR_DECLARE(RWLOCK_AGAIN);
CINELERRA_ERROR_DECLARE(RWLOCK_DEADLOCK);
/**
* RWLock.
*
*/
struct cinelerra_rwlock_struct
{
pthread_rwlock_t rwlock;
};
typedef struct cinelerra_rwlock_struct cinelerra_rwlock;
typedef cinelerra_rwlock* CinelerraRWLock;
CinelerraRWLock
cinelerra_rwlock_init (CinelerraRWLock self);
CinelerraRWLock
cinelerra_rwlock_destroy (CinelerraRWLock self);
/**
* rwlockacquirer used to manage the state of a rwlock variable.
*/
struct cinelerra_rwlockacquirer_struct
{
CinelerraRWLock rwlock;
enum cinelerra_lockstate state;
};
typedef struct cinelerra_rwlockacquirer_struct cinelerra_rwlockacquirer;
typedef struct cinelerra_rwlockacquirer_struct* CinelerraRWLockacquirer;
/* helper function for nobug */
static inline void
cinelerra_rwlockacquirer_ensureunlocked (CinelerraRWLockacquirer self)
{
ENSURE (self->state == CINELERRA_UNLOCKED, "forgot to unlock the rwlock mutex");
}
/* override with a macro to use the cleanup checker */
#define cinelerra_rwlockacquirer \
cinelerra_rwlockacquirer NOBUG_CLEANUP(cinelerra_rwlockacquirer_ensureunlocked)
CinelerraRWLockacquirer
cinelerra_rwlockacquirer_init (CinelerraRWLockacquirer self, CinelerraRWLock rwlock, enum cinelerra_lockstate state);
CinelerraRWLockacquirer
cinelerra_rwlockacquirer_rdlock (CinelerraRWLockacquirer self);
CinelerraRWLockacquirer
cinelerra_rwlockacquirer_wrlock (CinelerraRWLockacquirer self);
/**
* release rwlock.
* a rwlockacquirer must be unlocked before leaving scope
* @param self rwlockacquirer associated with a rwlock variable
*/
static inline void
cinelerra_rwlockacquirer_unlock (CinelerraRWLockacquirer self)
{
REQUIRE (self);
REQUIRE (self->state != CINELERRA_UNLOCKED, "rwlock was not locked");
if (pthread_rwlock_unlock (&self->rwlock->rwlock))
CINELERRA_DIE;
self->state = CINELERRA_UNLOCKED;
}
#endif