/// "Do on main thread" support.
static void iothread_service_main_thread_requests(void) {
ASSERT_IS_MAIN_THREAD();
// Move the queue to a local variable.
std::queue<main_thread_request_t *> request_queue;
{
scoped_lock queue_lock(s_main_thread_request_q_lock);
request_queue.swap(s_main_thread_request_queue);
}
if (!request_queue.empty()) {
// Perform each of the functions. Note we are NOT responsible for deleting these. They are
// stack allocated in their respective threads!
while (!request_queue.empty()) {
main_thread_request_t *req = request_queue.front();
request_queue.pop();
req->func();
req->done = true;
}
// Ok, we've handled everybody. Announce the good news, and allow ourselves to be unlocked.
// Note we must do this while holding the lock. Otherwise we race with the waiting threads:
//
// 1. waiting thread checks for done, sees false
// 2. main thread performs request, sets done to true, posts to condition
// 3. waiting thread unlocks lock, waits on condition (forever)
//
// Because the waiting thread performs step 1 under the lock, if we take the lock, we avoid
// posting before the waiting thread is waiting.
scoped_lock broadcast_lock(s_main_thread_performer_lock);
s_main_thread_performer_cond.notify_all();
}
}
/* "Do on main thread" support */
static void iothread_service_main_thread_requests(void)
{
ASSERT_IS_MAIN_THREAD();
// Move the queue to a local variable
std::queue<MainThreadRequest_t *> request_queue;
{
scoped_lock queue_lock(s_main_thread_request_queue_lock);
std::swap(request_queue, s_main_thread_request_queue);
}
if (! request_queue.empty())
{
// Perform each of the functions
// Note we are NOT responsible for deleting these. They are stack allocated in their respective threads!
while (! request_queue.empty())
{
MainThreadRequest_t *req = request_queue.front();
request_queue.pop();
req->handlerResult = req->handler(req->context);
req->done = true;
}
/* Ok, we've handled everybody. Announce the good news, and allow ourselves to be unlocked. Note we must do this while holding the lock. Otherwise we race with the waiting threads:
1. waiting thread checks for done, sees false
2. main thread performs request, sets done to true, posts to condition
3. waiting thread unlocks lock, waits on condition (forever)
Because the waiting thread performs step 1 under the lock, if we take the lock, we avoid posting before the waiting thread is waiting.
*/
scoped_lock broadcast_lock(s_main_thread_performer_lock);
VOMIT_ON_FAILURE(pthread_cond_broadcast(&s_main_thread_performer_condition));
}
}