Get rid of ASCII control chars in values

2 files changed, 16 insertions, 2 deletions

diff --git a/NEWS b/NEWS
index 03a5831..4f025c0 100644
--- a/NEWS
+++ b/NEWS
@@ -1,6 +1,13 @@
 NEWS file for ttystatus
 =======================
 
+Version 0.30, released UNRELEASED
+---------------------------------
+
+* Strip ASCII control characters from displayed output (but expand
+  TABs) in widget values. This avoids TABs making values longer than
+  expected, and terminals getting confused by control sequences.
+
 Version 0.29, released 2015-10-10
 ---------------------------------
 
diff --git a/ttystatus/status.py b/ttystatus/status.py
index 46e291f..148b8ff 100644
--- a/ttystatus/status.py
+++ b/ttystatus/status.py
@@ -117,16 +117,23 @@ class TerminalStatus(object):
 
         for i, w in enumerate(widget_row):
             if w.static_width:
-                texts[i] = w.render(0)
+                texts[i] = self._make_safe(w.render(0))
                 remaining -= len(texts[i])
 
         for i, w in enumerate(widget_row):
             if not w.static_width:
-                texts[i] = w.render(remaining)
+                texts[i] = self._make_safe(w.render(remaining))
                 remaining -= len(texts[i])
 
         return (''.join(texts))[:max_chars]
 
+    def _make_safe(self, line):
+        '''Expand TABs, remove all other ASCII control characters.'''
+        ASCII_SPACE = 32
+        return ''.join(
+            c if ord(c) >= ASCII_SPACE else ''
+            for c in line.expandtabs())
+
     def _write(self):
         '''Render and output current state of all widgets.'''
         self._m.write(self._render())