http.c: Use curl_multi_fdset to select on curl fds instead of just sleeping

Instead of sleeping unconditionally for a 50ms, when no data can be read
from the http connection(s), use curl_multi_fdset() to obtain the actual
file descriptors of the open connections and use them in the select call.
This way, the 50ms sleep is interrupted when new data arrives.

Signed-off-by: Mika Fischer <[email protected]>
Helped-by: Daniel Stenberg <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: mika-fischer

http.c

@@ -651,14 +651,14 @@ void run_active_slot(struct active_request_slot *slot)
 		}
 
 		if (slot->in_use && !data_received) {
-			max_fd = 0;
+			max_fd = -1;
 			FD_ZERO(&readfds);
 			FD_ZERO(&writefds);
 			FD_ZERO(&excfds);
+			curl_multi_fdset(curlm, &readfds, &writefds, &excfds, &max_fd);
 			select_timeout.tv_sec = 0;
 			select_timeout.tv_usec = 50000;
-			select(max_fd, &readfds, &writefds,
-			       &excfds, &select_timeout);
+			select(max_fd+1, &readfds, &writefds, &excfds, &select_timeout);
 		}
 	}
 #else