app: Flush URCs before rsp_send()

The data_send() API was already flushing URC messages before sending
the data to the pipe.

Now if application uses rsp_send() or rsp_send_to() outside of
AT command context and combined with data_send() it causes
URC messages to be appended in between two calls. Example:
   rsp_send_to(pipe, "#XRECV: ...");
   data_send(pipe, data);  /**< this causes URCs to be flushed */

The response in the AT channel would be:
   #XRECV: ...
   #XAPOLL: <example urc>
   data

The easiest fix would be to apply same mechanism to urc_send() as
the data_send() already does.

For clarify, use rsp_send_to() on all callbacks that might execute
from poll work handler.

Signed-off-by: Seppo Takalo <seppo.takalo@nordicsemi.no>

Author: SeppoTakalo

app/src/sm_at_host.c

@@ -1489,6 +1489,15 @@ void rsp_send(const char *fmt, ...)
 	struct sm_at_host_ctx *ctx = sm_at_host_get_current();
 	va_list arg_ptr;
 
+	if (!sm_at_ctx_check(ctx)) {
+		LOG_ERR("invalid context");
+		return;
+	}
+
+	if (is_idle(ctx)) {
+		flush_pipe_urcs(ctx);
+	}
+
 	va_start(arg_ptr, fmt);
 	rsp_send_internal(ctx, false, fmt, arg_ptr);
 	va_end(arg_ptr);
@@ -1499,6 +1508,15 @@ void rsp_send_to(struct modem_pipe *pipe, const char *fmt, ...)
 	struct sm_at_host_ctx *ctx = sm_at_host_get_ctx_from(pipe);
 	va_list arg_ptr;
 
+	if (!sm_at_ctx_check(ctx)) {
+		LOG_ERR("invalid context");
+		return;
+	}
+
+	if (is_idle(ctx)) {
+		flush_pipe_urcs(ctx);
+	}
+
 	va_start(arg_ptr, fmt);
 	rsp_send_internal(ctx, false, fmt, arg_ptr);
 	va_end(arg_ptr);

app/src/sm_at_socket.c

@@ -259,7 +259,7 @@ static void auto_reception(struct sm_socket *sock)
 	}
 	if (!in_datamode(sock->pipe)) {
 		/* <CR><LF> after the data. */
-		rsp_send("\r\n");
+		rsp_send_to(sock->pipe, "\r\n");
 	}
 }
 
@@ -1127,7 +1127,7 @@ static int do_recv(struct sm_socket *sock, int timeout, int flags,
 		LOG_WRN("zsock_recv() return 0");
 	} else {
 		if (!in_datamode(sock->pipe)) {
-			rsp_send("\r\n#XRECV: %d,%d,%d\r\n", sock->fd, mode, ret);
+			rsp_send_to(sock->pipe, "\r\n#XRECV: %d,%d,%d\r\n", sock->fd, mode, ret);
 		}
 
 		if (mode == AT_SOCKET_MODE_HEX) {
@@ -1242,7 +1242,7 @@ static int do_recvfrom(struct sm_socket *sock, int timeout, int flags,
 			uint16_t peer_port = 0;
 
 			util_get_peer_addr((struct net_sockaddr *)&remote, peer_addr, &peer_port);
-			rsp_send("\r\n#XRECVFROM: %d,%d,%d,\"%s\",%d\r\n", sock->fd,
+			rsp_send_to(sock->pipe, "\r\n#XRECVFROM: %d,%d,%d,\"%s\",%d\r\n", sock->fd,
 				    mode, ret, peer_addr, peer_port);
 		}