Handle NUL in text in places that g_utf8_strlen () was used

While pango-layout doesn't allow NUL in text, the lower level API should
handle it correctly.  We were using g_utf8_strlen() in a number of
places.  This is problematic since that function stops processing at
NUL even if length>1.  We now use an internal pango_utf8_strlen() instead.

Inspired by:
Bug 588678 – pango crash: install a new theme from gnome-appearance-properties

1 files changed, 27 insertions, 0 deletions

diff --git a/pango/pango-impl-utils.h b/pango/pango-impl-utils.h
index a04d4241..3ef3a0c4 100644
--- a/pango/pango-impl-utils.h
+++ b/pango/pango-impl-utils.h
@@ -122,6 +122,33 @@ pango_utf8_strwidth (const gchar *p)
   return len;
 }
 
+/* Glib's g_utf8_strlen() is broken and stops at embedded NUL's.
+ * Wrap it here. */
+static G_GNUC_UNUSED glong
+pango_utf8_strlen (const gchar *p, gssize max)
+{
+  glong len = 0;
+  const gchar *start = p;
+  g_return_val_if_fail (p != NULL || max == 0, 0);
+
+  if (max <= 0)
+    return g_utf8_strlen (p, max);
+
+  p = g_utf8_next_char (p);
+  while (p - start < max)
+    {
+      ++len;
+      p = g_utf8_next_char (p);
+    }
+
+  /* only do the last len increment if we got a complete
+   * char (don't count partial chars)
+   */
+  if (p - start <= max)
+    ++len;
+
+  return len;
+}
 
 G_END_DECLS