@@ -58,6 +58,7 @@ Index
   is much slower. The thing is that properly writing a tree from an index involves
   creating several tree objects, so in the end it might be slower. 
   Hmm, probably its okay to use the command unless we go c(++)
+* Implement diff so that temporary indices can be used as well ( using file swapping )
 * Proper merge handling with index and working copy
 * Checkout individual blobs using the index and git-checkout. Blobs can already 
   be written using their stream_data method.
@@ -74,6 +75,8 @@ Refs
   TagReference.create(repo, name
 * Ability to rename references and tags
 * Ability to remove references and tags
+* Ability to checkout a reference - 
+* Check whether we are the active reference HEAD.commit == self.commit
 
 Remote
 ------
 
@@ -146,6 +146,22 @@ def from_blob(cls, blob):
 		return IndexEntry((time, time, 0, 0, blob.mode, 0, 0, blob.size, blob.id, 0, blob.path))
 
 
+def default_index(func):
+	"""
+	Decorator assuring the wrapped method may only run if we are the default 
+	repository index. This is as we rely on git commands that operate 
+	on that index only.
+	"""
+	def check_default_index(self, *args, **kwargs):
+		if self._file_path != self._index_path():
+			raise AssertionError( "Cannot call %r on indices that do not represent the default git index" % func.__name__ )
+		return func(self, *args, **kwargs)
+	# END wrpaper method
+	
+	check_default_index.__name__ = func.__name__
+	return check_default_index
+
+
 class IndexFile(LazyMixin, diff.Diffable):
 	"""
 	Implements an Index that can be manipulated using a native implementation in 
@@ -487,6 +503,22 @@ def resolve_blobs(self, iter_blobs):
 		# END for each blob
 
 		return self
+		
+	def update(self):
+		"""
+		Reread the contents of our index file, discarding all cached information 
+		we might have.
+		
+		Note:
+			This is a possibly dangerious operations as it will discard your changes
+			to index.endtries
+			
+		Returns
+			self
+		"""
+		del(self.entries)
+		self.entries
+		return self
 
 	def write_tree(self):
 		"""
@@ -512,6 +544,88 @@ def _process_diff_args(self, args):
 		# END remove self
 		return args
 
+	@default_index
+	def add(self, items, **kwargs):
+		"""
+		Add files from the working copy, specific blobs or IndexEntries 
+		to the index.
+		
+		TODO: Its important to specify a way to add symlinks directly, even 
+		on systems that do not support it, like ... erm ... windows.
+		
+		``**kwargs``
+			Additional keyword arguments to be passed to git-update-index
+			
+		Returns
+			List(IndexEntries) representing the entries just added
+		"""
+		raise NotImplementedError("todo")
+		
+	@default_index
+	def remove(self, items, affect_working_tree=False, **kwargs):
+		"""
+		Remove the given file_paths or blobs from the index and optionally from 
+		the working tree as well.
+		
+		``items``
+			TODO
+		
+		``affect_working_tree``
+			If True, the entry will also be removed from the working tree, physically
+			removing the respective file. This may fail if there are uncommited changes
+			in it.
+			
+		``**kwargs``
+			Additional keyword arguments to be passed to git-update-index
+			
+		Returns
+			self
+		"""
+		raise NotImplementedError("todo")
+		return self
+		
+	@default_index
+	def commit(self, message=None, parent_commits=None,  **kwargs):
+		"""
+		Commit the current index, creating a commit object.
+		
+		``message``
+			Commit message
+			
+		``parent_commits``
+			Optional Commit objects to use as parents for the new commit. 
+			If None or empty, the current head commit will be the parent of the 
+			new commit object
+			
+		``**kwargs``
+			Additional keyword arguments passed to git-commit
+		
+		Returns
+			Commit object representing the new commit
+		"""
+		raise NotImplementedError("todo")
+		
+	@default_index
+	def reset(self, commit='HEAD', working_tree=False, **kwargs):
+		"""
+		Reset the index to reflect the tree at the given commit. This will not
+		adjust our HEAD reference as opposed to HEAD.reset.
+		
+		``commit``
+			Revision, Reference or Commit specifying the commit we should represent.
+			If you want to specify a tree only, use IndexFile.from_tree and overwrite
+			the default index.
+			
+		``working_tree``
+			If True, the files in the working tree will reflect the changed index.
+			If False, the working tree will not be touched
+			
+		``**kwargs``
+			Additional keyword arguments passed to git-reset
+		"""
+		raise NotImplementedError("todo")
+		
+	@default_index
 	def diff(self, other=diff.Diffable.Index, paths=None, create_patch=False, **kwargs):
 		"""
 		Diff this index against the working copy or a Tree or Commit object
@@ -523,10 +637,6 @@ def diff(self, other=diff.Diffable.Index, paths=None, create_patch=False, **kwar
 			Will only work with indices that represent the default git index as 
 			they have not been initialized with a stream.
 		"""
-		# perhaps we shouldn't diff these at all, or we swap them in place first
-		if self._file_path != self._index_path():
-			raise AssertionError( "Cannot diff custom indices as they do not represent the default git index" )
-		
 		# index against index is always empty
 		if other is self.Index:
 			return diff.DiffIndex()
 
@@ -322,7 +322,8 @@ def reset(self, commit='HEAD', index=True, working_tree = False,
 				paths=None, **kwargs):
 		"""
 		Reset our HEAD to the given commit optionally synchronizing 
-		the index and working tree.
+		the index and working tree. The reference we refer to will be set to 
+		commit as well.
 		
 		``commit``
 			Commit object, Reference Object or string identifying a revision we 
 
@@ -26,6 +26,11 @@ def test_index_file_base(self):
 			val = getattr(entry, attr)
 		# END for each method
 
+		# test update
+		entries = index.entries
+		assert isinstance(index.update(), IndexFile)
+		assert entries is not index.entries
+		
 		# test stage
 		index_merge = IndexFile(self.rorepo, fixture_path("index_merge"))
 		assert len(index_merge.entries) == 106
@@ -140,3 +145,11 @@ def test_index_file_diffing(self, rw_repo):
 
 		# against something unusual
 		self.failUnlessRaises(ValueError, index.diff, int)
+		
+		self.fail( "Test IndexFile.reset" )
+		
+	@with_rw_repo('0.1.6')
+	def test_index_mutation(self, rw_repo):
+		# add / remove / commit / Working Tree Handling 
+		self.fail( "add, remove, commit, working tree handling" )
+