experimental:

- Merge in changes from pluggablebackends.

wicd/backend.py

@@ -0,0 +1,97 @@
+#!/usr/bin/env python
+
+""" Backend manager for wicd.
+
+Manages and loads the pluggable backends for wicd.
+
+"""
+
+#
+#   Copyright (C) 2007 Adam Blackburn
+#   Copyright (C) 2007 Dan O'Reilly
+#   Copyright (C) 2007 Byron Hillis
+#
+#   This program is free software; you can redistribute it and/or modify
+#   it under the terms of the GNU General Public License Version 2 as
+#   published by the Free Software Foundation.
+#
+#   This program is distributed in the hope that it will be useful,
+#   but WITHOUT ANY WARRANTY; without even the implied warranty of
+#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#   GNU General Public License for more details.
+#
+#   You should have received a copy of the GNU General Public License
+#   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+
+
+import sys
+import os
+
+import wicd.wpath as wpath
+
+
+class BackendManager(object):
+    def __init__(self):
+        """ Initialize the backend manager. """
+        self.backend_dir = wpath.backends
+        self.__loaded_backend = None
+        
+    def _valid_backend_file(self, be_file):
+        """ Make sure the backend file is valid. """
+        return (os.access(be_file, os.F_OK) and 
+                os.path.basename(be_file).startswith("be-") and
+                be_file.endswith(".py"))
+    
+    def get_current_backend(self):
+        if self.__loaded_backend and not self.__loaded_backend is None:
+            return self.__loaded_backend.NAME
+        else:
+            return None
+    
+    def get_available_backends(self):
+        """ Returns a list of all valid backends in the backend directory. """
+        be_list = [""]
+        for f in os.listdir(self.backend_dir):
+            if self._valid_backend_file(os.path.join(self.backend_dir, f)):
+                be_list.append(f[3:-3])
+        return be_list
+        
+    def load_backend(self, backend_name):
+        """ Load and return a backend module. 
+        
+        Given a backend name be-foo, attempt to load a python module
+        in the backends directory called be-foo.py.  The module must
+        include a certain set of classes and variables to be considered
+        valid.
+        
+        """
+        def fail(backend_name, reason):
+            print "Failed to load backend %s: %s" % (backend_name, reason)
+            
+        print 'trying to load backend %s' % backend_name
+        backend_path = os.path.join(self.backend_dir,
+                                    'be-' + backend_name + '.py')
+        if self._valid_backend_file(backend_path):
+            sys.path.insert(0, self.backend_dir)
+            backend = __import__('be-' + backend_name)
+        else:
+            fail(backend_name, 'Invalid backend file.')
+            return None
+        
+        if not backend.NAME:
+            fail(backend_name, 'Missing NAME declaration.')
+            return None
+        
+        if not backend.WiredInterface:
+            fail(backend_name, "Missing WiredInterface class")
+            return None
+        
+        if not backend.WirelessInterface:
+            fail(backend_name, "Missing WirelessInterface class")
+            return None
+
+        self.__loaded_backend = backend
+        print 'successfully loaded backend %s' % backend_name
+        return backend
+