Ensure fatal errors are sent first

Once we start enqueueing asynchronous events, it's more important to
send fatal errors (which then disconnect) imediately by prepending them
to the send queue. Everything else is still processed FIFO.

Signed-off-by: Jim Ramsay <[email protected]>

src/ctl-server.c

@@ -35,6 +35,11 @@
 #define FAILED_TO(action) \
 	nvnc_log(NVNC_LOG_WARNING, "Failed to " action ": %m");
 
+enum send_priority {
+	SEND_FIFO,
+	SEND_IMMEDIATE,
+};
+
 enum cmd_type {
 	CMD_HELP,
 	CMD_VERSION,
@@ -377,8 +382,24 @@ static void client_set_aml_event_mask(struct ctl_client* self)
 	aml_set_event_mask(self->handler, mask);
 }
 
+static int client_enqueue(struct ctl_client* self, json_t* message,
+		enum send_priority priority)
+{
+	int result;
+	switch(priority) {
+	case SEND_IMMEDIATE:
+		result = json_array_insert(self->response_queue, 0, message);
+		break;
+	case SEND_FIFO:
+		result = json_array_append(self->response_queue, message);
+		break;
+	}
+	client_set_aml_event_mask(self);
+	return result;
+}
+
 static int client_enqueue_jsonipc(struct ctl_client* self,
-		struct jsonipc_response* resp)
+		struct jsonipc_response* resp, enum send_priority priority)
 {
 	int result = 0;
 	json_error_t err;
@@ -388,12 +409,9 @@ static int client_enqueue_jsonipc(struct ctl_client* self,
 		result = -1;
 		goto failure;
 	}
-	result = json_array_append_new(self->response_queue, packed_response);
-	if (result != 0) {
+	result = client_enqueue(self, packed_response, priority);
+	if (result != 0)
 		nvnc_log(NVNC_LOG_WARNING, "Append failed");
-		goto failure;
-	}
-	client_set_aml_event_mask(self);
 failure:
 	jsonipc_response_destroy(resp);
 	return result;
@@ -403,11 +421,12 @@ static int client_enqueue_error(struct ctl_client* self,
 		struct jsonipc_error* err, json_t* id)
 {
 	struct jsonipc_response* resp = jsonipc_error_response_new(err, id);
-	return client_enqueue_jsonipc(self, resp);
+	return client_enqueue_jsonipc(self, resp, SEND_FIFO);
 }
 
-static int client_enqueue_response(struct ctl_client* self,
-		struct cmd_response* response, json_t* id)
+static int client_enqueue__response(struct ctl_client* self,
+		struct cmd_response* response, json_t* id,
+		enum send_priority priority)
 {
 	nvnc_log(NVNC_LOG_INFO, "Enqueueing response: %s (%d)",
 			response->code == 0 ? "OK" : "FAILED", response->code);
@@ -420,13 +439,19 @@ static int client_enqueue_response(struct ctl_client* self,
 	struct jsonipc_response* resp =
 		jsonipc_response_new(response->code, response->data, id);
 	cmd_response_destroy(response);
-	return client_enqueue_jsonipc(self, resp);
+	return client_enqueue_jsonipc(self, resp, priority);
+}
+
+static int client_enqueue_response(struct ctl_client* self,
+		struct cmd_response* response, json_t* id)
+{
+	return client_enqueue__response(self, response, id, SEND_FIFO);
 }
 
 static int client_enqueue_internal_error(struct ctl_client* self,
 		struct cmd_response* err)
 {
-	int result = client_enqueue_response(self, err, NULL);
+	int result = client_enqueue__response(self, err, NULL, SEND_IMMEDIATE);
 	if (result != 0)
 		client_destroy(self);
 	self->drop_after_next_send = true;