[gedit] modeline: do not advance beyond string end

[Paolo Borelli <pborelli src gnome org>]

commit b3a4e29300d50f8fa1c759a11408216671c9a275
Author: Paolo Borelli <pborelli gnome org>
Date:   Sun May 8 11:07:42 2016 +0200

    modeline: do not advance beyond string end
    
    If while parsing a modeline we already reach \0 we should not
    increment the pointer, we must instead break out of the loop.

 plugins/modelines/modeline-parser.c |   23 +++++++++++++++++------
 1 files changed, 17 insertions(+), 6 deletions(-)
---
diff --git a/plugins/modelines/modeline-parser.c b/plugins/modelines/modeline-parser.c
index 33de301..095c0ae 100644
--- a/plugins/modelines/modeline-parser.c
+++ b/plugins/modelines/modeline-parser.c
@@ -573,18 +573,21 @@ parse_kate_modeline (gchar           *s,
  * Line numbers are counted starting at one.
  */
 static void
-parse_modeline (gchar           *s,
+parse_modeline (gchar           *line,
                gint             line_number,
                gint             line_count,
                ModelineOptions *options)
 {
-       gchar prev;
+       gchar *s = line;
 
        /* look for the beginning of a modeline */
-       for (prev = ' '; (s != NULL) && (*s != '\0'); prev = *(s++))
+       while (s != NULL && *s != '\0')
        {
-               if (!g_ascii_isspace (prev))
+               if (s > line && !g_ascii_isspace (*(s - 1)))
+               {
+                       s++;
                        continue;
+               }
 
                if ((line_number <= 3 || line_number > line_count - 3) &&
                    (strncmp (s, "ex:", 3) == 0 ||
@@ -593,8 +596,12 @@ parse_modeline (gchar           *s,
                {
                        gedit_debug_message (DEBUG_PLUGINS, "Vim modeline on line %d", line_number);
 
-                       while (*s != ':') s++;
-                       s = parse_vim_modeline (s + 1, options);
+                       while (*s != ':')
+                       {
+                               s++;
+                       }
+
+                       s = parse_vim_modeline (s + 1, options);
                }
                else if (line_number <= 2 && strncmp (s, "-*-", 3) == 0)
                {
@@ -609,6 +616,10 @@ parse_modeline (gchar           *s,
 
                        s = parse_kate_modeline (s + 5, options);
                }
+               else
+               {
+                       s++;
+               }
        }
 }