fix up a pylint error and migrate some pure functions from terminal.py

terminatorlib/util.py

@@ -18,6 +18,8 @@
 
 import sys
 import gtk
+import os
+import pwd
 
 # set this to true to enable debugging output
 DEBUG = True
@@ -39,11 +41,57 @@ def gerr(message = None):
             gtk.MESSAGE_ERROR, gtk.BUTTONS_OK, message)
     dialog.run()
 
-def has_ancestor(widget, type):
+def has_ancestor(widget, wtype):
     """Walk up the family tree of widget to see if any ancestors are of type"""
     while widget:
         widget = widget.get_parent()
-        if isinstance(widget, type):
+        if isinstance(widget, wtype):
             return(True)
     return(False)
 
+def path_lookup(command):
+    '''Find a command in our path'''
+    if os.path.isabs(command):
+        if os.path.isfile(command):
+            return(command)
+        else:
+            return(None)
+    elif command[:2] == './' and os.path.isfile(command):
+        dbg('path_lookup: Relative filename %s found in cwd' % command)
+        return(command)
+
+    try:
+        paths = os.environ['PATH'].split(':')
+        if len(paths[0]) == 0: 
+            raise(ValueError)
+    except (ValueError, NameError):
+        dbg('path_lookup: PATH not set in environment, using fallbacks')
+        paths = ['/usr/local/bin', '/usr/bin', '/bin']
+
+    dbg('path_lookup: Using %d paths: %s', (len(paths), paths))
+
+    for path in paths:
+        target = os.path.join(path, command)
+        if os.path.isfile(target):
+            dbg('path_lookup: found %s' % target)
+            return(target)
+
+    dbg('path_lookup: Unable to locate %s' % command)
+
+def shell_lookup():
+    """Find an appropriate shell for the user"""
+    shells = [os.getenv('SHELL'), pwd.getpwuid(os.getuid())[6], 'bash',
+            'zsh', 'tcsh', 'ksh', 'csh', 'sh']
+
+    for shell in shells:
+        if shell is None:
+            continue
+        elif os.path.isfile(shell):
+            return(shell)
+        else:
+            rshell = path_lookup(shell)
+            if rshell is not None:
+                dbg('shell_lookup: Found %s at %s' % (shell, rshell))
+                return(rshell)
+    dbg('shell_lookup: Unable to locate a shell')
+