From 1017f2ff20af7d93e21284058939c2782d6d356a Mon Sep 17 00:00:00 2001
From: =?utf8?q?Ji=C5=99=C3=AD=20Mat=C4=9Bj=C3=A1k?=
 <jiri.matejak@fel.cvut.cz>
Date: Mon, 21 May 2018 21:05:44 +0200
Subject: [PATCH] each line is sent only once, default is empty

---
 mt_server.c | 37 ++++++++++++++++++++-----------------
 1 file changed, 20 insertions(+), 17 deletions(-)

diff --git a/mt_server.c b/mt_server.c
index f7315e1..cb5ba02 100644
--- a/mt_server.c
+++ b/mt_server.c
@@ -10,6 +10,7 @@ char *new_line()
     char *line = (char *)malloc((LWS_PRE + INPUT_LINE_LENGTH)*sizeof(char));
     if (!line) {
         perror("malloc");
+        return NULL;
     }
     return line + LWS_PRE;
 }
@@ -19,7 +20,7 @@ char *copy_line(char *line) {
     if (!copy) {
         return NULL;
     }
-    strcpy(copy, line);
+    strncpy(copy, line, INPUT_LINE_LENGTH);
 }
 
 void free_line(char *line)
@@ -178,13 +179,24 @@ static int callback_merica_terminal(struct lws *wsi,
             break;
 
         case LWS_CALLBACK_SERVER_WRITEABLE:
-            line = lines->first->line;
-            n = strlen(line);
-            m = lws_write(wsi, (unsigned char *)line, n, LWS_WRITE_TEXT);
-            if (lines->first->next != NULL) {
+            if (lines->first) {
+                line = lines->first->line;
+                n = strlen(line);
+                m = lws_write(wsi, (unsigned char *)line, n, LWS_WRITE_TEXT);
                 list_remove(lines);
-                lws_callback_on_writable_all_protocol(lws_get_context(wsi),
-                    &protocols[PROTOCOL_MERICA_TERMINAL]);
+                if (lines->first) {
+                    lws_callback_on_writable_all_protocol(lws_get_context(wsi),
+                        &protocols[PROTOCOL_MERICA_TERMINAL]);
+                }
+            } else {
+                line = copy_line(JSON_EMPTY);
+                if (line) {
+                    n = strlen(line);
+                    m = lws_write(wsi, (unsigned char *)line, n, LWS_WRITE_TEXT);
+                    free_line(line);
+                } else {
+                    return -1;
+                }
             }
             if (m < n) {
                 fprintf(stderr, "ERROR %d writing to di socket\n", n);
@@ -264,21 +276,12 @@ int mt_server_init(mt_server_t *self, struct ev_loop *loop, int fd)
 
     ev_io_ws *w = &(self->fd_watcher);
     w->context = context;
-    char *line = copy_line(JSON_EMPTY);
-    if (!line) {
-        return -1;
-    }
     w->lines = list_init();
     if (!w->lines) {
-        free_line(line);
-        return -1;
-    }
-    if (list_add(w->lines, line) != 0) {
-        list_deinit(w->lines);
         return -1;
     }
     protocols[PROTOCOL_MERICA_TERMINAL].user = (void *)w->lines;
-    line = new_line();
+    char *line = new_line();
     if (!line) {
         list_deinit(w->lines);
         return -1;
-- 
2.39.2