add checks in curses ui for small windows

addch() and addstr() throw an exception if text has to be printed
outside of the window. This may occur if the terminal is very small.
Such erroneous prints are no-ops now.

Signed-off-by: Mart Lubbers <mart@martlubbers.net>

offlineimap/ui/Curses.py

@@ -137,7 +137,13 @@ class CursesAccountFrame:
         sleepstr = '%3d:%02d'% (secs // 60, secs % 60) if secs else 'active'
         accstr = '%s: [%s] %12.12s: '% (self.acc_num, sleepstr, self.account)
 
-        self.ui.exec_locked(self.window.addstr, 0, 0, accstr)
+        def addstr():
+            try:
+                self.window.addstr(0, 0, accstr)
+            except curses.error as e: # Occurs when the terminal is very small
+                pass
+        self.ui.exec_locked(addstr);
+
         self.location = len(accstr)
 
     def setwindow(self, curses_win, acc_num):
@@ -211,7 +217,10 @@ class CursesThreadFrame:
 
     def display(self):
         def locked_display():
-            self.window.addch(self.y, self.x, '@', self.curses_color)
+            try:
+                self.window.addch(self.y, self.x, '@', self.curses_color)
+            except curses.error: # Occurs when the terminal is very small
+                pass
             self.window.refresh()
         # lock the curses IO while fudging stuff
         self.ui.exec_locked(locked_display)