[gnome-terminal/wip/rishi/window-title-truncate] window: Limit the title's length to avoid integer overflows in Pango

[Debarshi Ray <debarshir src gnome org>]

commit ebc9a39aa003a15b2d526f45908e2b8e6df950c9
Author: Debarshi Ray <debarshir gnome org>
Date:   Wed Mar 4 17:06:21 2020 +0100

    window: Limit the title's length to avoid integer overflows in Pango
    
    GtkLabels with really long texts of the order of 2^21 characters can
    cause integer overflows in Pango when measuring the width of the
    PangoLayout for that text. Tracking down the root cause of the overflow
    in the font stack and fixing it is difficult, so it's prudent to work
    around it by limiting the length of the window title to a sane, yet
    large enough, number.
    
    Pango does integer measurements in Pango units where 1 pixel is 2^10
    Pango units, and font glyphs are roughly 16, or 2^4, pixels wide.
    Therefore, roughly 2^(31-10-4), or 131072, characters is the threshold
    after which Pango might start to overflow.
    
    A limit of 1024 characters was chosen because that's the limit both
    VTE and xterm use for titles set through the OSC 0 escape sequence.
    
    https://gitlab.gnome.org/GNOME/gnome-terminal/issues/207

 src/terminal-window.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)
---
diff --git a/src/terminal-window.c b/src/terminal-window.c
index 7a8953c5..19f31fdd 100644
--- a/src/terminal-window.c
+++ b/src/terminal-window.c
@@ -2407,13 +2407,17 @@ sync_screen_title (TerminalScreen *screen,
 {
   TerminalWindowPrivate *priv = window->priv;
   const char *title;
+  gs_free char *title_truncated = NULL;
 
   if (screen != priv->active_screen)
     return;
 
   title = terminal_screen_get_title (screen);
-  gtk_window_set_title (GTK_WINDOW (window),
-                        title && title[0] ? title : _("Terminal"));
+  if (title == NULL || title[0] == '\0')
+    title = _("Terminal");
+
+  title_truncated = g_utf8_substring (title, 0, 1024);
+  gtk_window_set_title (GTK_WINDOW (window), title_truncated);
 }
 
 static void