rwlock first implementation
This commit is contained in:
Christian Thaeter
parent
04f9424ad8
commit
d508f7cb7a
4 changed files with 285 additions and 2 deletions
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@ -27,6 +27,7 @@ libcin3_a_SOURCES = \
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$(libcin3_a_srcdir)/time.c \
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$(libcin3_a_srcdir)/framerate.c \
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$(libcin3_a_srcdir)/mutex.c \
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$(libcin3_a_srcdir)/rwlock.c \
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$(libcin3_a_srcdir)/condition.c
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@ -37,5 +38,6 @@ noinst_HEADERS += \
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$(libcin3_a_srcdir)/framerate.h \
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$(libcin3_a_srcdir)/locking.h \
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$(libcin3_a_srcdir)/mutex.h \
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$(libcin3_a_srcdir)/rwlock.h \
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$(libcin3_a_srcdir)/condition.h
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@ -36,8 +36,8 @@ enum cinelerra_lockstate
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{
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CINELERRA_UNLOCKED,
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CINELERRA_LOCKED,
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CINELERRA_RLOCKED,
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CINELERRA_WLOCKED
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CINELERRA_RDLOCKED,
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CINELERRA_WRLOCKED
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};
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#endif
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142
src/lib/rwlock.c
Normal file
142
src/lib/rwlock.c
Normal file
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@ -0,0 +1,142 @@
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/*
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rwlock.c - read/write locks
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Copyright (C) CinelerraCV
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2007, Christian Thaeter <ct@pipapo.org>
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#define _GNU_SOURCE
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#include <errno.h>
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#include "lib/rwlock.h"
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CINELERRA_ERROR_DEFINE(RWLOCK_AGAIN, "maximum number of readlocks exceed");
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CINELERRA_ERROR_DEFINE(RWLOCK_DEADLOCK, "deadlock detected");
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CinelerraRWLock
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cinelerra_rwlock_init (CinelerraRWLock self)
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{
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if (self)
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{
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pthread_rwlock_init (&self->rwlock, NULL);
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}
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return self;
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}
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CinelerraRWLock
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cinelerra_rwlock_destroy (CinelerraRWLock self)
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{
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if (self)
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{
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if (pthread_rwlock_destroy (&self->rwlock))
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CINELERRA_DIE;
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}
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return self;
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}
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CinelerraRWLockacquirer
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cinelerra_rwlockacquirer_init (CinelerraRWLockacquirer self, CinelerraRWLock rwlock, enum cinelerra_lockstate state)
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{
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REQUIRE (self);
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REQUIRE (rwlock);
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REQUIRE (state != CINELERRA_LOCKED, "illegal state for rwlock");
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self->rwlock = rwlock;
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self->state = state;
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switch (state)
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{
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case CINELERRA_RDLOCKED:
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switch (pthread_rwlock_rdlock (&rwlock->rwlock))
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{
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case 0:
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break;
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case EAGAIN:
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cinelerra_error_set (CINELERRA_ERROR_RWLOCK_AGAIN);
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return NULL;
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case EDEADLK:
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cinelerra_error_set (CINELERRA_ERROR_RWLOCK_DEADLOCK);
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return NULL;
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default:
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CINELERRA_DIE;
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}
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case CINELERRA_WRLOCKED:
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switch (pthread_rwlock_wrlock (&rwlock->rwlock))
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{
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case 0:
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break;
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case EDEADLK:
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cinelerra_error_set (CINELERRA_ERROR_RWLOCK_DEADLOCK);
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return NULL;
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default:
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CINELERRA_DIE;
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}
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default:
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break;
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}
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return self;
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}
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CinelerraRWLockacquirer
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cinelerra_rwlockacquirer_rdlock (CinelerraRWLockacquirer self)
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{
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REQUIRE (self);
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REQUIRE (self->state == CINELERRA_UNLOCKED, "rwlock already locked");
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switch (pthread_rwlock_rdlock (&self->rwlock->rwlock))
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{
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case 0:
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break;
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case EAGAIN:
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cinelerra_error_set (CINELERRA_ERROR_RWLOCK_AGAIN);
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return NULL;
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case EDEADLK:
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cinelerra_error_set (CINELERRA_ERROR_RWLOCK_DEADLOCK);
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return NULL;
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default:
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CINELERRA_DIE;
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}
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self->state = CINELERRA_RDLOCKED;
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return self;
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}
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CinelerraRWLockacquirer
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cinelerra_rwlockacquirer_wrlock (CinelerraRWLockacquirer self)
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{
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REQUIRE (self);
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REQUIRE (self->state == CINELERRA_UNLOCKED, "rwlock already locked");
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switch (pthread_rwlock_wrlock (&self->rwlock->rwlock))
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{
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case 0:
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break;
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case EDEADLK:
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cinelerra_error_set (CINELERRA_ERROR_RWLOCK_DEADLOCK);
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return NULL;
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default:
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CINELERRA_DIE;
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}
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self->state = CINELERRA_WRLOCKED;
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return self;
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}
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139
src/lib/rwlock.h
Normal file
139
src/lib/rwlock.h
Normal file
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@ -0,0 +1,139 @@
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/*
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rwlock.h - read/write locks
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Copyright (C) CinelerraCV
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2007, Christian Thaeter <ct@pipapo.org>
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#ifndef CINELERRA_RWLOCK_H
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#define CINELERRA_RWLOCK_H
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#ifndef _GNU_SOURCE
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#error "This header must be included with _GNU_SOURCE or _POSIX_C_SOURCE >= 200112L defined"
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#endif
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#include <pthread.h>
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#include <nobug.h>
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#include "lib/locking.h"
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CINELERRA_ERROR_DECLARE(RWLOCK_AGAIN);
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CINELERRA_ERROR_DECLARE(RWLOCK_DEADLOCK);
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/**
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* RWLock.
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*
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*/
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struct cinelerra_rwlock_struct
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{
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pthread_rwlock_t rwlock;
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};
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typedef struct cinelerra_rwlock_struct cinelerra_rwlock;
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typedef cinelerra_rwlock* CinelerraRWLock;
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/**
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* Initialize a rwlock
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* @param self is a pointer to the rwlock to be initialized
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* @return self as given
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*/
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CinelerraRWLock
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cinelerra_rwlock_init (CinelerraRWLock self);
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/**
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* destroy a rwlock
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* @param self is a pointer to the rwlock to be initialized
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* @return self on success or NULL at error
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*/
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CinelerraRWLock
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cinelerra_rwlock_destroy (CinelerraRWLock self);
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/**
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* rwlockacquirer used to manage the state of a rwlock variable.
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*/
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struct cinelerra_rwlockacquirer_struct
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{
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CinelerraRWLock rwlock;
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enum cinelerra_lockstate state;
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};
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typedef struct cinelerra_rwlockacquirer_struct cinelerra_rwlockacquirer;
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typedef struct cinelerra_rwlockacquirer_struct* CinelerraRWLockacquirer;
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/* helper function for nobug */
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static inline void
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cinelerra_rwlockacquirer_ensureunlocked (CinelerraRWLockacquirer self)
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{
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ENSURE (self->state == CINELERRA_UNLOCKED, "forgot to unlock the rwlock mutex");
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}
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/* override with a macro to use the cleanup checker */
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#define cinelerra_rwlockacquirer \
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cinelerra_rwlockacquirer NOBUG_CLEANUP(cinelerra_rwlockacquirer_ensureunlocked)
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/**
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* initialize a rwlockacquirer state
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* @param self rwlockacquirer to be initialized, must be an automatic variable
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* @param cond associated rwlock
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* @param state initial state of the mutex, either CINELERRA_RDLOCKED, CINELERRA_WRLOCKED or CINELERRA_UNLOCKED
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* @return self as given or NULL on error
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*/
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CinelerraRWLockacquirer
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cinelerra_rwlockacquirer_init (CinelerraRWLockacquirer self, CinelerraRWLock rwlock, enum cinelerra_lockstate state);
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/**
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* readlock the rwlock.
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* must not already be locked
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* @param self rwlockacquirer associated with a rwlock
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* @return self as given or NULL on error
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*/
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CinelerraRWLockacquirer
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cinelerra_rwlockacquirer_rdlock (CinelerraRWLockacquirer self);
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/**
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* writelock the rwlock.
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* must not already be locked
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* @param self rwlockacquirer associated with a rwlock
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* @return self as given or NULL on error
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*/
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CinelerraRWLockacquirer
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cinelerra_rwlockacquirer_wrlock (CinelerraRWLockacquirer self);
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/**
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* release rwlock.
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* a rwlockacquirer must be unlocked before leaving scope
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* @param self rwlockacquirer associated with a rwlock variable
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*/
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static inline void
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cinelerra_rwlockacquirer_unlock (CinelerraRWLockacquirer self)
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{
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REQUIRE (self);
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REQUIRE (self->state != CINELERRA_UNLOCKED, "rwlock was not locked");
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if (pthread_rwlock_unlock (&self->rwlock->rwlock))
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CINELERRA_DIE;
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self->state = CINELERRA_UNLOCKED;
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}
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#endif
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