APU_DECLARE(apr_status_t) apr_reslist_acquire(apr_reslist_t *reslist,
void **resource)
{
apr_status_t rv;
apr_res_t *res;
apr_thread_mutex_lock(reslist->listlock);
/* If there are idle resources on the available list, use
* them right away. */
if (reslist->nidle > 0) {
/* Pop off the first resource */
res = pop_resource(reslist);
*resource = res->opaque;
free_container(reslist, res);
apr_thread_mutex_unlock(reslist->listlock);
return APR_SUCCESS;
}
/* If we've hit our max, block until we're allowed to create
* a new one, or something becomes free. */
else while (reslist->ntotal >= reslist->hmax
&& reslist->nidle <= 0) {
if (reslist->timeout) {
if ((rv = apr_thread_cond_timedwait(reslist->avail,
reslist->listlock, reslist->timeout)) != APR_SUCCESS) {
apr_thread_mutex_unlock(reslist->listlock);
return rv;
}
}
else
apr_thread_cond_wait(reslist->avail, reslist->listlock);
}
/* If we popped out of the loop, first try to see if there
* are new resources available for immediate use. */
if (reslist->nidle > 0) {
res = pop_resource(reslist);
*resource = res->opaque;
free_container(reslist, res);
apr_thread_mutex_unlock(reslist->listlock);
return APR_SUCCESS;
}
/* Otherwise the reason we dropped out of the loop
* was because there is a new slot available, so create
* a resource to fill the slot and use it. */
else {
rv = create_resource(reslist, &res);
if (rv == APR_SUCCESS) {
reslist->ntotal++;
*resource = res->opaque;
}
free_container(reslist, res);
apr_thread_mutex_unlock(reslist->listlock);
return rv;
}
}
static apr_status_t reslist_cleanup(void *data_)
{
apr_status_t rv;
apr_reslist_t *rl = data_;
apr_res_t *res;
apr_thread_mutex_lock(rl->listlock);
while (rl->nidle > 0) {
res = pop_resource(rl);
rl->ntotal--;
rv = destroy_resource(rl, res);
if (rv != APR_SUCCESS) {
return rv;
}
free_container(rl, res);
}
assert(rl->nidle == 0);
assert(rl->ntotal == 0);
apr_thread_mutex_destroy(rl->listlock);
apr_thread_cond_destroy(rl->avail);
return APR_SUCCESS;
}
/**
* Perform routine maintenance on the resource list. This call
* may instantiate new resources or expire old resources.
*/
static apr_status_t reslist_maint(apr_reslist_t *reslist)
{
apr_time_t now;
apr_status_t rv;
apr_res_t *res;
int created_one = 0;
apr_thread_mutex_lock(reslist->listlock);
/* Check if we need to create more resources, and if we are allowed to. */
while (reslist->nidle < reslist->min && reslist->ntotal <= reslist->hmax) {
/* Create the resource */
rv = create_resource(reslist, &res);
if (rv != APR_SUCCESS) {
free_container(reslist, res);
apr_thread_mutex_unlock(reslist->listlock);
return rv;
}
/* Add it to the list */
push_resource(reslist, res);
/* Update our counters */
reslist->ntotal++;
/* If someone is waiting on that guy, wake them up. */
rv = apr_thread_cond_signal(reslist->avail);
if (rv != APR_SUCCESS) {
apr_thread_mutex_unlock(reslist->listlock);
return rv;
}
created_one++;
}
/* We don't need to see if we're over the max if we were under it before */
if (created_one) {
apr_thread_mutex_unlock(reslist->listlock);
return APR_SUCCESS;
}
/* Check if we need to expire old resources */
now = apr_time_now();
while (reslist->nidle > reslist->smax && reslist->nidle > 0) {
/* Peak at the first resource in the list */
res = APR_RING_FIRST(&reslist->avail_list);
/* See if the oldest entry should be expired */
if (now - res->freed < reslist->ttl) {
/* If this entry is too young, none of the others
* will be ready to be expired either, so we are done. */
break;
}
res = pop_resource(reslist);
reslist->ntotal--;
rv = destroy_resource(reslist, res);
if (rv != APR_SUCCESS) {
apr_thread_mutex_unlock(reslist->listlock);
return rv;
}
free_container(reslist, res);
}
apr_thread_mutex_unlock(reslist->listlock);
return APR_SUCCESS;
}