connection: Write before reading connection data

wayland/connection.c

@@ -251,68 +251,68 @@ wl_connection_data(struct wl_connection *connection, uint32_t mask)
 	char cmsg[128];
 	int len, count, clen;
 
-	if (mask & WL_CONNECTION_READABLE) {
-		wl_buffer_put_iov(&connection->in, iov, &count);
+	if (mask & WL_CONNECTION_WRITABLE) {
+		wl_buffer_get_iov(&connection->out, iov, &count);
+
+		build_cmsg(&connection->fds_out, cmsg, &clen);
 
 		msg.msg_name = NULL;
 		msg.msg_namelen = 0;
 		msg.msg_iov = iov;
 		msg.msg_iovlen = count;
 		msg.msg_control = cmsg;
-		msg.msg_controllen = sizeof cmsg;
+		msg.msg_controllen = clen;
 		msg.msg_flags = 0;
 
 		do {
-			len = recvmsg(connection->fd, &msg, 0);
+			len = sendmsg(connection->fd, &msg, 0);
 		} while (len < 0 && errno == EINTR);
 
 		if (len < 0) {
 			fprintf(stderr,
-				"read error from connection %p: %m (%d)\n",
-				connection, errno);
-			return -1;
-		} else if (len == 0) {
-			/* FIXME: Handle this better? */
+				"write error for connection %p, fd %d: %m\n",
+				connection, connection->fd);
 			return -1;
 		}
 
-		decode_cmsg(&connection->fds_in, &msg);
-
-		connection->in.head += len;
-	}	
+		close_fds(&connection->fds_out);
 
-	if (mask & WL_CONNECTION_WRITABLE) {
-		wl_buffer_get_iov(&connection->out, iov, &count);
+		connection->out.tail += len;
+		if (connection->out.tail == connection->out.head)
+			connection->update(connection,
+					   WL_CONNECTION_READABLE,
+					   connection->data);
+	}
 
-		build_cmsg(&connection->fds_out, cmsg, &clen);
+	if (mask & WL_CONNECTION_READABLE) {
+		wl_buffer_put_iov(&connection->in, iov, &count);
 
 		msg.msg_name = NULL;
 		msg.msg_namelen = 0;
 		msg.msg_iov = iov;
 		msg.msg_iovlen = count;
 		msg.msg_control = cmsg;
-		msg.msg_controllen = clen;
+		msg.msg_controllen = sizeof cmsg;
 		msg.msg_flags = 0;
 
 		do {
-			len = sendmsg(connection->fd, &msg, 0);
+			len = recvmsg(connection->fd, &msg, 0);
 		} while (len < 0 && errno == EINTR);
 
 		if (len < 0) {
 			fprintf(stderr,
-				"write error for connection %p, fd %d: %m\n",
-				connection, connection->fd);
+				"read error from connection %p: %m (%d)\n",
+				connection, errno);
+			return -1;
+		} else if (len == 0) {
+			/* FIXME: Handle this better? */
 			return -1;
 		}
 
-		close_fds(&connection->fds_out);
+		decode_cmsg(&connection->fds_in, &msg);
 
-		connection->out.tail += len;
-		if (connection->out.tail == connection->out.head)
-			connection->update(connection,
-					   WL_CONNECTION_READABLE,
-					   connection->data);
-	}
+		connection->in.head += len;
+	}	
 
 	return connection->in.head - connection->in.tail;
 }