Fix connection problems when using mosquitto_connect_async().

The connection wouldn't always complete if mosquitto_loop_start() was
called before mosquitto_connect_async(). Closes #848.

Thanks to Ian Gough.

Bug: https://github.com/eclipse/mosquitto/issues/848

Signed-off-by: Roger A. Light <roger@atchoo.org>

ChangeLog.txt

@@ -21,6 +21,8 @@ Library:
 - Fix some places where return codes were incorrect, including to the
   on_disconnect() callback. This has resulted in two new error codes,
   MOSQ_ERR_KEEPALIVE and MOSQ_ERR_LOOKUP.
+- Fix connection problems when mosquitto_loop_start() was called before
+  mosquitto_connect_async(). Closes #848.
 
 
 1.5 - 20180502

lib/connect.c

@@ -178,6 +178,9 @@ static int mosquitto__reconnect(struct mosquitto *mosq, bool blocking)
 	}else
 #endif
 	{
+		pthread_mutex_lock(&mosq->state_mutex);
+		mosq->state = mosq_cs_connecting;
+		pthread_mutex_unlock(&mosq->state_mutex);
 		rc = net__socket_connect(mosq, mosq->host, mosq->port, mosq->bind_address, blocking);
 	}
 	if(rc>0){

lib/mosquitto_internal.h

@@ -107,6 +107,7 @@ enum mosquitto_client_state {
 	mosq_cs_socks5_userpass_reply = 13,
 	mosq_cs_socks5_send_userpass = 14,
 	mosq_cs_expiring = 15,
+	mosq_cs_connecting = 16,
 };
 
 enum mosquitto__protocol {

lib/thread_mosq.c

@@ -79,15 +79,27 @@ int mosquitto_loop_stop(struct mosquitto *mosq, bool force)
 void *mosquitto__thread_main(void *obj)
 {
 	struct mosquitto *mosq = obj;
+	int state;
 
 	if(!mosq) return NULL;
 
-	pthread_mutex_lock(&mosq->state_mutex);
+	do{
-	if(mosq->state == mosq_cs_connect_async){
+		pthread_mutex_lock(&mosq->state_mutex);
+		state = mosq->state;
 		pthread_mutex_unlock(&mosq->state_mutex);
+		if(state == mosq_cs_new){
+#ifdef WIN32
+			Sleep(10);
+#else
+			usleep(10000);
+#endif
+		}else{
+			break;
+		}
+	}while(1);
+
+	if(state == mosq_cs_connect_async){
 		mosquitto_reconnect(mosq);
-	}else{
-		pthread_mutex_unlock(&mosq->state_mutex);
 	}
 
 	if(!mosq->keepalive){