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| | #include "pthread_impl.h"
#include <threads.h>
static inline __cnd_t* __cnd_init(__cnd_t *c, __mtx_t *m) {
if (c) {
*c = (__cnd_t) {
.rfs = 2,
.mtx = m,
.wts = 1,
.seq = 0,
};
}
if (m) __mtx_addref(m);
return c;
}
static inline void __cnd_delete(__cnd_t *c) __attribute__((nonnull(1)));
static inline void __cnd_delete(__cnd_t *c) {
__mtx_unref(c->mtx);
c->mtx = 0;
free(c);
}
void __cnd_unref(__cnd_t *c) {
if (a_fetch_add(&c->rfs, -1) == 1) {
__cnd_delete(c);
}
}
static inline __cnd_t* __cnd_getref_def(cnd_t *cond, __mtx_t* m, __cnd_t* def, int * seq) __attribute__((nonnull(1,2)));
static inline __cnd_t* __cnd_getref_def(cnd_t *cond, __mtx_t* m, __cnd_t* def, int * seq) {
__cnd_t * ret;
/* Critical section protected by lock. */
__lock(&cond->_cx_lock);
ret = cond->_cx_cnd;
if (ret) {
if (m) {
/* Has the cnd just been initialized? */
if (!ret->mtx) {
__mtx_addref(m);
ret->mtx = m;
/* If not, is it consistent with previous usage? */
} else if (ret->mtx != m) {
ret = 0;
goto UNLOCK;
}
}
++ret->wts;
__cnd_addref(ret);
*seq = ret->seq;
} else if (def) {
ret = def;
cond->_cx_cnd = def;
}
UNLOCK:
__unlock(&cond->_cx_lock);
return ret;
}
__cnd_t* __cnd_getref(cnd_t *cond, __mtx_t * m, int * seq) {
__cnd_t * ret = __cnd_getref_def(cond, m, 0, seq);
if (!ret) {
__cnd_t * new = __cnd_init(malloc(sizeof *ret), m);
if (new) {
ret = __cnd_getref_def(cond, m, new, seq);
/* somebody sneaked in between the first and second call */
if (ret != new) __cnd_delete(new);
}
}
return ret;
}
|