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#ifndef ATOMIC_RWLOCK_INCLUDED
#define ATOMIC_RWLOCK_INCLUDED
/* Copyright (c) 2006 MySQL AB, 2009 Sun Microsystems, Inc.
Use is subject to license terms.
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; version 2 of the License.
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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */
#define MY_ATOMIC_MODE_RWLOCKS 1
#ifdef MY_ATOMIC_MODE_DUMMY
/*
the following can never be enabled by ./configure, one need to put #define in
a source to trigger the following warning. The resulting code will be broken,
it only makes sense to do it to see now test_atomic detects broken
implementations (another way is to run a UP build on an SMP box).
*/
#warning MY_ATOMIC_MODE_DUMMY and MY_ATOMIC_MODE_RWLOCKS are incompatible
typedef char my_atomic_rwlock_t;
#define my_atomic_rwlock_destroy(name)
#define my_atomic_rwlock_init(name)
#define my_atomic_rwlock_rdlock(name)
#define my_atomic_rwlock_wrlock(name)
#define my_atomic_rwlock_rdunlock(name)
#define my_atomic_rwlock_wrunlock(name)
#define MY_ATOMIC_MODE "dummy (non-atomic)"
#else /* not MY_ATOMIC_MODE_DUMMY */
typedef struct {pthread_mutex_t rw;} my_atomic_rwlock_t;
#ifndef SAFE_MUTEX
/*
we're using read-write lock macros but map them to mutex locks, and they're
faster. Still, having semantically rich API we can change the
underlying implementation, if necessary.
*/
#define my_atomic_rwlock_destroy(name) pthread_mutex_destroy(& (name)->rw)
#define my_atomic_rwlock_init(name) pthread_mutex_init(& (name)->rw, 0)
#define my_atomic_rwlock_rdlock(name) pthread_mutex_lock(& (name)->rw)
#define my_atomic_rwlock_wrlock(name) pthread_mutex_lock(& (name)->rw)
#define my_atomic_rwlock_rdunlock(name) pthread_mutex_unlock(& (name)->rw)
#define my_atomic_rwlock_wrunlock(name) pthread_mutex_unlock(& (name)->rw)
#else /* SAFE_MUTEX */
/*
SAFE_MUTEX pollutes the compiling name space with macros
that alter pthread_mutex_t, pthread_mutex_init, etc.
Atomic operations should never use the safe mutex wrappers.
Unfortunately, there is no way to have both:
- safe mutex macros expanding pthread_mutex_lock to safe_mutex_lock
- my_atomic macros expanding to unmodified pthread_mutex_lock
inlined in the same compilation unit.
So, in case of SAFE_MUTEX, a function call is required.
Given that SAFE_MUTEX is a debugging facility,
this extra function call is not a performance concern for
production builds.
*/
C_MODE_START
extern void plain_pthread_mutex_init(safe_mutex_t *);
extern void plain_pthread_mutex_destroy(safe_mutex_t *);
extern void plain_pthread_mutex_lock(safe_mutex_t *);
extern void plain_pthread_mutex_unlock(safe_mutex_t *);
C_MODE_END
#define my_atomic_rwlock_destroy(name) plain_pthread_mutex_destroy(&(name)->rw)
#define my_atomic_rwlock_init(name) plain_pthread_mutex_init(&(name)->rw)
#define my_atomic_rwlock_rdlock(name) plain_pthread_mutex_lock(&(name)->rw)
#define my_atomic_rwlock_wrlock(name) plain_pthread_mutex_lock(&(name)->rw)
#define my_atomic_rwlock_rdunlock(name) plain_pthread_mutex_unlock(&(name)->rw)
#define my_atomic_rwlock_wrunlock(name) plain_pthread_mutex_unlock(&(name)->rw)
#endif /* SAFE_MUTEX */
#define MY_ATOMIC_MODE "mutex"
#ifndef MY_ATOMIC_MODE_RWLOCKS
#define MY_ATOMIC_MODE_RWLOCKS 1
#endif
#endif
#define make_atomic_add_body(S) int ## S sav; sav= *a; *a+= v; v=sav;
#define make_atomic_fas_body(S) int ## S sav; sav= *a; *a= v; v=sav;
#define make_atomic_cas_body(S) if ((ret= (*a == *cmp))) *a= set; else *cmp=*a;
#define make_atomic_load_body(S) ret= *a;
#define make_atomic_store_body(S) *a= v;
#endif /* ATOMIC_RWLOCK_INCLUDED */
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