Dynamically load all modules and their card classes from the cards directory

git-svn-id: svn+ssh://localhost/home/henryk/svn/cyberflex-shell/trunk@42 f711b948-2313-0410-aaa9-d29f33439f0b

cards/__init__.py

@@ -1,14 +1,35 @@
-"""This package contains different card-specific modules."""
-from generic_card import Card
-from java_card import Java_Card
-from cyberflex_card import Cyberflex_Card
-from sys import modules
+"""This package contains different card-specific modules.
+
+The __init__.py file will automatically load all modules in the cards directory
+and import all classes that have a DRIVER_NAME attribute. If you want to write
+your own classes you should therefore make sure it has a DRIVER_NAME and then
+put it in the same directory as the other classes. Preferably you should derive
+from the generic_card.Card class."""
+
+from sys import modules as _modules
+from dircache import listdir as _listdir
+
+for filename in _listdir(_modules[__name__].__path__[0]):
+    if filename[-3:].lower() == ".py":
+        possible_module = filename[:-3]
+        if possible_module.lower() == "__init__":
+            continue
+        try:
+            module = __import__(possible_module, globals(), locals(), [])
+            for possible_class in dir(module):
+                if hasattr(getattr(module, possible_class), "DRIVER_NAME"):
+                    setattr(_modules[__name__], possible_class, getattr(module, possible_class))
+        except ImportError:
+            pass
+
+
+del filename, possible_module, module, possible_class
 
 def find_class(ATR):
     """Find a card class that supports the card identified by ATR. 
     Returns the generic card class when no better match is found."""
-    for card_class in dir(modules[__name__]):
-        card_class = getattr(modules[__name__], card_class)
+    for card_class in dir(_modules[__name__]):
+        card_class = getattr(_modules[__name__], card_class)
         if hasattr(card_class, "can_handle"):
             if card_class.can_handle(ATR):
                 return card_class