Fix issue where signal strength wouldn't be reported correctly if the first link quality regex didn't match.

Add some helper methods that will eventually be used for encryption template parsing.
Use more specific exception checking in a few places.

wicd/backends/be-ioctl.py

@@ -33,8 +33,7 @@ from wicd import misc
 from wicd import wnettools
 from wicd import wpath
 from wicd.wnettools import *
-from wicd.wnettools import strength_pattern, altstrength_pattern, wep_pattern, \
-                           signaldbm_pattern
+from wicd.wnettools import wep_pattern, signaldbm_pattern
 
 import iwscan
 import wpactrl
@@ -311,17 +310,10 @@ class WirelessInterface(Interface, wnettools.BaseWirelessInterface):
             
         # Link Quality
         ap['qual_found'] = True
-        try:
-            [(strength, max_strength)] = strength_pattern.findall(cell["stats"])
-            if max_strength:
-                ap["quality"] = 100 * int(strength) // int(max_strength)
-            else:
-                ap["quality"] = int(strength)
-        except ValueError:
-            ap['quality'] = misc.RunRegex(altstrength_pattern,cell["stats"])
-            if not ap['quality']:
-                ap['qual_found'] = False
-                ap['quality'] = -1
+        ap['quality'] = self._get_link_quality(cell['stats'])
+        if ap['quality'] is None:
+            ap['qual_found'] = False
+            ap['quality'] = -1
 
         # Signal Strength (only used if user doesn't want link
         # quality displayed or it isn't found)
@@ -498,10 +490,12 @@ class WirelessInterface(Interface, wnettools.BaseWirelessInterface):
         buff = get_iw_ioctl_result(self.iface, SIOCGIWSTATS)
         strength = ord(buff[2])
         max_strength = self._get_max_strength()
-        if strength and max_strength:
+        if strength not in ['', None] and max_strength:
             return 100 * int(strength) // int(max_strength)
-        
-        return strength
+        elif strength not in ['', None]:
+            return int(strength)
+        else:
+            return None
     
     def _get_max_strength(self):
         """ Gets the maximum possible strength from the wireless driver. """