1 files changed, 76 insertions, 13 deletions

diff --git a/lib/git/utils.py b/lib/git/utils.py
index 5d0ba8ca..f84c247d 100644
--- a/lib/git/utils.py
+++ b/lib/git/utils.py
@@ -7,20 +7,83 @@
 import os
 
 def dashify(string):
-    return string.replace('_', '-')
+	return string.replace('_', '-')
 
 def touch(filename):
-    os.utime(filename)
+	os.utime(filename)
 
 def is_git_dir(d):
-    """ This is taken from the git setup.c:is_git_directory
-        function."""
-
-    if os.path.isdir(d) and \
-            os.path.isdir(os.path.join(d, 'objects')) and \
-            os.path.isdir(os.path.join(d, 'refs')):
-        headref = os.path.join(d, 'HEAD')
-        return os.path.isfile(headref) or \
-                (os.path.islink(headref) and
-                os.readlink(headref).startswith('refs'))
-    return False
+	""" This is taken from the git setup.c:is_git_directory
+		function."""
+
+	if os.path.isdir(d) and \
+			os.path.isdir(os.path.join(d, 'objects')) and \
+			os.path.isdir(os.path.join(d, 'refs')):
+		headref = os.path.join(d, 'HEAD')
+		return os.path.isfile(headref) or \
+				(os.path.islink(headref) and
+				os.readlink(headref).startswith('refs'))
+	return False
+	
+	
+class LazyMixin(object):
+	"""
+	Base class providing an interface to lazily retrieve attribute values upon 
+	first access. If slots are used, memory will only be reserved once the attribute
+	is actually accessed and retrieved the first time. All future accesses will 
+	return the cached value as stored in the Instance's dict or slot.
+	"""
+	__slots__ = tuple()
+	
+	def __getattr__(self, attr):
+		"""
+		Whenever an attribute is requested that we do not know, we allow it 
+		to be created and set. Next time the same attribute is reqeusted, it is simply
+		returned from our dict/slots.
+		"""
+		self._set_cache_(attr)
+		# will raise in case the cache was not created
+		return object.__getattribute__(self, attr)
+
+	def _set_cache_(self, attr):
+		""" This method should be overridden in the derived class. 
+		It should check whether the attribute named by attr can be created
+		and cached. Do nothing if you do not know the attribute or call your subclass
+		
+		The derived class may create as many additional attributes as it deems 
+		necessary in case a git command returns more information than represented 
+		in the single attribute."""
+		pass
+
+
+class Iterable(object):
+	"""
+	Defines an interface for iterable items which is to assure a uniform 
+	way to retrieve and iterate items within the git repository
+	"""
+	__slots__ = tuple()
+	
+	@classmethod
+	def list_items(cls, repo, *args, **kwargs):
+		"""
+		Find all items of this type - subclasses can specify args and kwargs differently.
+		If no args are given, subclasses are obliged to return all items if no additional 
+		arguments arg given.
+		
+		Note: Favor the iter_items method as it will 
+		
+		Returns:
+			list(Item,...) list of item instances 
+		"""
+		return list(cls.iter_items(repo, *args, **kwargs))
+		
+		
+	@classmethod
+	def iter_items(cls, repo, *args, **kwargs):
+		"""
+		For more information about the arguments, see list_items
+		Return: 
+			iterator yielding Items
+		"""
+		raise NotImplementedError("To be implemented by Subclass")
+