DISPATCH_NOINLINE
void
dispatch_group_notify_f(dispatch_group_t dg, dispatch_queue_t dq, void *ctxt,
void (*func)(void *))
{
dispatch_semaphore_t dsema = (dispatch_semaphore_t)dg;
struct dispatch_sema_notify_s *dsn, *prev;
// FIXME -- this should be updated to use the continuation cache
while (!(dsn = calloc(1, sizeof(*dsn)))) {
sleep(1);
}
dsn->dsn_queue = dq;
dsn->dsn_ctxt = ctxt;
dsn->dsn_func = func;
_dispatch_retain(dq);
dispatch_atomic_store_barrier();
prev = dispatch_atomic_xchg2o(dsema, dsema_notify_tail, dsn);
if (fastpath(prev)) {
prev->dsn_next = dsn;
} else {
_dispatch_retain(dg);
(void)dispatch_atomic_xchg2o(dsema, dsema_notify_head, dsn);
if (dsema->dsema_value == dsema->dsema_orig) {
_dispatch_group_wake(dsema);
}
}
}
DISPATCH_NOINLINE
long
_dispatch_semaphore_signal_slow(dispatch_semaphore_t dsema)
{
// Before dsema_sent_ksignals is incremented we can rely on the reference
// held by the waiter. However, once this value is incremented the waiter
// may return between the atomic increment and the semaphore_signal(),
// therefore an explicit reference must be held in order to safely access
// dsema after the atomic increment.
_dispatch_retain(dsema);
(void)dispatch_atomic_inc2o(dsema, dsema_sent_ksignals);
#if USE_MACH_SEM
_dispatch_semaphore_create_port(&dsema->dsema_port);
kern_return_t kr = semaphore_signal(dsema->dsema_port);
DISPATCH_SEMAPHORE_VERIFY_KR(kr);
#elif USE_POSIX_SEM
int ret = sem_post(&dsema->dsema_sem);
DISPATCH_SEMAPHORE_VERIFY_RET(ret);
#endif
_dispatch_release(dsema);
return 1;
}
DISPATCH_ALWAYS_INLINE
static inline void
_dispatch_data_init(dispatch_data_t data, const void *buffer, size_t size,
dispatch_queue_t queue, dispatch_block_t destructor)
{
data->buf = buffer;
data->size = size;
data->destructor = destructor;
if (queue) {
_dispatch_retain(queue);
data->do_targetq = queue;
}
}
void
dispatch_suspend(dispatch_object_t dou)
{
DISPATCH_OBJECT_TFB(_dispatch_objc_suspend, dou);
if (slowpath(dou._do->do_ref_cnt == DISPATCH_OBJECT_GLOBAL_REFCNT) ||
slowpath(dx_type(dou._do) == DISPATCH_QUEUE_ROOT_TYPE)) {
return;
}
// rdar://8181908 explains why we need to do an internal retain at every
// suspension.
(void)dispatch_atomic_add2o(dou._do, do_suspend_cnt,
DISPATCH_OBJECT_SUSPEND_INTERVAL, relaxed);
_dispatch_retain(dou._do);
}
void
dispatch_source_cancel(dispatch_source_t ds)
{
#if DISPATCH_DEBUG
dispatch_debug(as_do(ds), __FUNCTION__);
#endif
// Right after we set the cancel flag, someone else
// could potentially invoke the source, do the cancelation,
// unregister the source, and deallocate it. We would
// need to therefore retain/release before setting the bit
_dispatch_retain(as_do(ds));
dispatch_atomic_or(&ds->ds_atomic_flags, DSF_CANCELED);
_dispatch_wakeup(as_do(ds));
_dispatch_release(as_do(ds));
}
dispatch_source_t
dispatch_source_create(dispatch_source_type_t type,
uintptr_t handle,
uintptr_t mask,
dispatch_queue_t q)
{
dispatch_source_t ds = NULL;
static char source_label[sizeof(ds->dq_label)] = "source";
// input validation
if (type == NULL || (mask & ~type->mask)) {
goto out_bad;
}
ds = calloc(1ul, sizeof(struct dispatch_source_s));
if (slowpath(!ds)) {
goto out_bad;
}
// Initialize as a queue first, then override some settings below.
_dispatch_queue_init((dispatch_queue_t)ds);
memcpy(ds->dq_label, source_label, sizeof(source_label));
// Dispatch Object
ds->do_vtable = &_dispatch_source_kevent_vtable;
ds->do_ref_cnt++; // the reference the manger queue holds
ds->do_suspend_cnt = DISPATCH_OBJECT_SUSPEND_INTERVAL;
// do_targetq will be retained below, past point of no-return
ds->do_targetq = q;
if (slowpath(!type->init(ds, type, handle, mask, q))) {
goto out_bad;
}
dispatch_assert(!(ds->ds_is_level && ds->ds_is_adder));
#if DISPATCH_DEBUG
dispatch_debug(as_do(ds), __FUNCTION__);
#endif
_dispatch_retain(as_do(ds->do_targetq));
return ds;
out_bad:
free(ds);
return NULL;
}
