-#######->WARNING<-####### Directory structure changed, see commit message

If you use git-python as a submodule of your own project, which alters the sys.path to import it,
you will have to adjust your code to take the changed directory structure into consideration.

Previously, you would put the path
./git-python/lib

into your syspath. All modules moved one level up into the 'git' subdirectory, which means that the 'git-python' directory
now contains the 'git' root package. To allow git to be found, add ./git-python into your path.

To finalize your update, run the following commands

git submodule update --init --recursive

As there will be left-over directories, consider running git-clean

7 files changed, 1405 insertions, 0 deletions

diff --git a/git/refs/__init__.py b/git/refs/__init__.py
new file mode 100644
index 00000000..fc8ce644
--- /dev/null
+++ b/git/refs/__init__.py
@@ -0,0 +1,21 @@
+
+# import all modules in order, fix the names they require
+from symbolic import *
+from reference import *
+from head import *
+from tag import *
+from remote import *
+
+# name fixes
+import head
+head.RemoteReference = RemoteReference
+del(head)
+
+
+import symbolic
+for item in (HEAD, Head, RemoteReference, TagReference, Reference, SymbolicReference):
+	setattr(symbolic, item.__name__, item)
+del(symbolic)
+
+
+from log import *
diff --git a/git/refs/head.py b/git/refs/head.py
new file mode 100644
index 00000000..d8729434
--- /dev/null
+++ b/git/refs/head.py
@@ -0,0 +1,246 @@
+from symbolic import SymbolicReference
+from reference import Reference
+
+from git.config import SectionConstraint
+
+from git.util import join_path
+
+from git.exc import GitCommandError
+
+__all__ = ["HEAD", "Head"]
+
+
+	
+class HEAD(SymbolicReference):
+	"""Special case of a Symbolic Reference as it represents the repository's 
+	HEAD reference."""
+	_HEAD_NAME = 'HEAD'
+	_ORIG_HEAD_NAME = 'ORIG_HEAD'
+	__slots__ = tuple()
+	
+	def __init__(self, repo, path=_HEAD_NAME):
+		if path != self._HEAD_NAME:
+			raise ValueError("HEAD instance must point to %r, got %r" % (self._HEAD_NAME, path))
+		super(HEAD, self).__init__(repo, path)
+	
+	def orig_head(self):
+		"""
+		:return: SymbolicReference pointing at the ORIG_HEAD, which is maintained 
+			to contain the previous value of HEAD"""
+		return SymbolicReference(self.repo, self._ORIG_HEAD_NAME)
+		
+	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 reference we refer to will be set to 
+		commit as well.
+		
+		:param commit:
+			Commit object, Reference Object or string identifying a revision we 
+			should reset HEAD to.
+			
+		:param index:
+			If True, the index will be set to match the given commit. Otherwise
+			it will not be touched.
+		
+		:param working_tree:
+			If True, the working tree will be forcefully adjusted to match the given
+			commit, possibly overwriting uncommitted changes without warning.
+			If working_tree is True, index must be true as well
+		
+		:param paths:
+			Single path or list of paths relative to the git root directory
+			that are to be reset. This allows to partially reset individual files.
+		
+		:param kwargs:
+			Additional arguments passed to git-reset. 
+		
+		:return: self"""
+		mode = "--soft"
+		add_arg = None
+		if index:
+			mode = "--mixed"
+			
+			# it appears, some git-versions declare mixed and paths deprecated
+			# see http://github.com/Byron/GitPython/issues#issue/2
+			if paths:
+				mode = None
+			# END special case
+		# END handle index
+			
+		if working_tree:
+			mode = "--hard"
+			if not index:
+				raise ValueError( "Cannot reset the working tree if the index is not reset as well")
+			
+		# END working tree handling
+		
+		if paths:
+			add_arg = "--"
+		# END nicely separate paths from rest
+		
+		try:
+			self.repo.git.reset(mode, commit, add_arg, paths, **kwargs)
+		except GitCommandError, e:
+			# git nowadays may use 1 as status to indicate there are still unstaged
+			# modifications after the reset
+			if e.status != 1:
+				raise
+		# END handle exception
+		
+		return self
+	
+
+class Head(Reference):
+	"""A Head is a named reference to a Commit. Every Head instance contains a name
+	and a Commit object.
+
+	Examples::
+
+		>>> repo = Repo("/path/to/repo")
+		>>> head = repo.heads[0]
+
+		>>> head.name
+		'master'
+
+		>>> head.commit
+		<git.Commit "1c09f116cbc2cb4100fb6935bb162daa4723f455">
+
+		>>> head.commit.hexsha
+		'1c09f116cbc2cb4100fb6935bb162daa4723f455'"""
+	_common_path_default = "refs/heads"
+	k_config_remote = "remote"
+	k_config_remote_ref = "merge"			# branch to merge from remote
+	
+	@classmethod
+	def delete(cls, repo, *heads, **kwargs):
+		"""Delete the given heads
+		:param force:
+			If True, the heads will be deleted even if they are not yet merged into
+			the main development stream.
+			Default False"""
+		force = kwargs.get("force", False)
+		flag = "-d"
+		if force:
+			flag = "-D"
+		repo.git.branch(flag, *heads)
+		
+	def set_tracking_branch(self, remote_reference):
+		"""
+		Configure this branch to track the given remote reference. This will alter
+			this branch's configuration accordingly.
+		
+		:param remote_reference: The remote reference to track or None to untrack 
+			any references
+		:return: self"""
+		if remote_reference is not None and not isinstance(remote_reference, RemoteReference):
+			raise ValueError("Incorrect parameter type: %r" % remote_reference)
+		# END handle type
+		
+		writer = self.config_writer()
+		if remote_reference is None:
+			writer.remove_option(self.k_config_remote)
+			writer.remove_option(self.k_config_remote_ref)
+			if len(writer.options()) == 0:
+				writer.remove_section()
+			# END handle remove section
+		else:
+			writer.set_value(self.k_config_remote, remote_reference.remote_name)
+			writer.set_value(self.k_config_remote_ref, Head.to_full_path(remote_reference.remote_head))
+		# END handle ref value
+		
+		return self
+		
+		
+	def tracking_branch(self):
+		"""
+		:return: The remote_reference we are tracking, or None if we are 
+			not a tracking branch"""
+		reader = self.config_reader()
+		if reader.has_option(self.k_config_remote) and reader.has_option(self.k_config_remote_ref):
+			ref = Head(self.repo, Head.to_full_path(reader.get_value(self.k_config_remote_ref)))
+			remote_refpath = RemoteReference.to_full_path(join_path(reader.get_value(self.k_config_remote), ref.name))
+			return RemoteReference(self.repo, remote_refpath)
+		# END handle have tracking branch
+		
+		# we are not a tracking branch
+		return None
+	
+	def rename(self, new_path, force=False):
+		"""Rename self to a new path
+		
+		:param new_path:
+			Either a simple name or a path, i.e. new_name or features/new_name.
+			The prefix refs/heads is implied
+			
+		:param force:
+			If True, the rename will succeed even if a head with the target name
+			already exists.
+			
+		:return: self
+		:note: respects the ref log as git commands are used"""
+		flag = "-m"
+		if force:
+			flag = "-M"
+			
+		self.repo.git.branch(flag, self, new_path)
+		self.path  = "%s/%s" % (self._common_path_default, new_path)
+		return self
+		
+	def checkout(self, force=False, **kwargs):
+		"""Checkout this head by setting the HEAD to this reference, by updating the index
+		to reflect the tree we point to and by updating the working tree to reflect 
+		the latest index.
+		
+		The command will fail if changed working tree files would be overwritten.
+		
+		:param force:
+			If True, changes to the index and the working tree will be discarded.
+			If False, GitCommandError will be raised in that situation.
+			
+		:param kwargs:
+			Additional keyword arguments to be passed to git checkout, i.e.
+			b='new_branch' to create a new branch at the given spot.
+		
+		:return:
+			The active branch after the checkout operation, usually self unless
+			a new branch has been created.
+		
+		:note:
+			By default it is only allowed to checkout heads - everything else
+			will leave the HEAD detached which is allowed and possible, but remains
+			a special state that some tools might not be able to handle."""
+		args = list()
+		kwargs['f'] = force
+		if kwargs['f'] == False:
+			kwargs.pop('f')
+		
+		self.repo.git.checkout(self, **kwargs)
+		return self.repo.active_branch
+		
+	#{ Configruation
+	
+	def _config_parser(self, read_only):
+		if read_only:
+			parser = self.repo.config_reader()
+		else:
+			parser = self.repo.config_writer()
+		# END handle parser instance
+		
+		return SectionConstraint(parser, 'branch "%s"' % self.name)
+	
+	def config_reader(self):
+		"""
+		:return: A configuration parser instance constrained to only read 
+			this instance's values"""
+		return self._config_parser(read_only=True)
+		
+	def config_writer(self):
+		"""
+		:return: A configuration writer instance with read-and write acccess
+			to options of this head"""
+		return self._config_parser(read_only=False)
+	
+	#} END configuration
+		
+
diff --git a/git/refs/log.py b/git/refs/log.py
new file mode 100644
index 00000000..f49c07fd
--- /dev/null
+++ b/git/refs/log.py
@@ -0,0 +1,282 @@
+from git.util import (
+						join_path,
+						Actor,
+						LockedFD,
+						LockFile,
+						assure_directory_exists,
+						to_native_path,
+					)
+
+from gitdb.util import (
+						bin_to_hex,
+						join,
+						file_contents_ro_filepath,
+					)
+
+from git.objects.util import (
+								parse_date,
+								Serializable, 
+								utctz_to_altz,
+								altz_to_utctz_str,
+							)
+
+import time
+import os
+import re
+
+__all__ = ["RefLog", "RefLogEntry"]
+
+
+class RefLogEntry(tuple):
+	"""Named tuple allowing easy access to the revlog data fields"""
+	_fmt = "%s %s %s <%s> %i %s\t%s\n"
+	_re_hexsha_only = re.compile('^[0-9A-Fa-f]{40}$')
+	__slots__ = tuple()
+	
+	def __repr__(self):
+		"""Representation of ourselves in git reflog format"""
+		act = self.actor
+		time = self.time
+		return self._fmt % (self.oldhexsha, self.newhexsha, act.name, act.email, 
+							time[0], altz_to_utctz_str(time[1]), self.message)
+	
+	@property
+	def oldhexsha(self):
+		"""The hexsha to the commit the ref pointed to before the change""" 
+		return self[0]
+		
+	@property
+	def newhexsha(self):
+		"""The hexsha to the commit the ref now points to, after the change"""
+		return self[1]
+		
+	@property
+	def actor(self):
+		"""Actor instance, providing access"""
+		return self[2]
+		
+	@property
+	def time(self):
+		"""time as tuple:
+		
+		* [0] = int(time)
+		* [1] = int(timezone_offset) in time.altzone format """
+		return self[3]
+		
+	@property
+	def message(self):
+		"""Message describing the operation that acted on the reference"""
+		return self[4]
+	
+	@classmethod
+	def new(self, oldhexsha, newhexsha, actor, time, tz_offset, message):
+		""":return: New instance of a RefLogEntry"""
+		if not isinstance(actor, Actor):
+			raise ValueError("Need actor instance, got %s" % actor)
+		# END check types 
+		return RefLogEntry((oldhexsha, newhexsha, actor, (time, tz_offset), message))
+		
+	@classmethod
+	def from_line(cls, line):
+		""":return: New RefLogEntry instance from the given revlog line.
+		:param line: line without trailing newline
+		:raise ValueError: If line could not be parsed"""
+		try:
+			info, msg = line.split('\t', 2)
+		except ValueError:
+			raise ValueError("line is missing tab separator")
+		#END handle first plit
+		oldhexsha = info[:40]
+		newhexsha = info[41:81]
+		for hexsha in (oldhexsha, newhexsha):
+			if not cls._re_hexsha_only.match(hexsha):
+				raise ValueError("Invalid hexsha: %s" % hexsha)
+			# END if hexsha re doesn't match
+		#END for each hexsha
+		
+		email_end = info.find('>', 82)
+		if email_end == -1:
+			raise ValueError("Missing token: >")
+		#END handle missing end brace
+		
+		actor = Actor._from_string(info[82:email_end+1])
+		time, tz_offset = parse_date(info[email_end+2:])
+		
+		return RefLogEntry((oldhexsha, newhexsha, actor, (time, tz_offset), msg))
+		
+
+class RefLog(list, Serializable):
+	"""A reflog contains reflog entries, each of which defines a certain state
+	of the head in question. Custom query methods allow to retrieve log entries 
+	by date or by other criteria.
+	
+	Reflog entries are orded, the first added entry is first in the list, the last
+	entry, i.e. the last change of the head or reference, is last in the list."""
+	
+	__slots__ = ('_path', )
+	
+	def __new__(cls, filepath=None):
+		inst = super(RefLog, cls).__new__(cls)
+		return inst
+		
+	def __init__(self, filepath=None):
+		"""Initialize this instance with an optional filepath, from which we will
+		initialize our data. The path is also used to write changes back using 
+		the write() method"""
+		self._path = filepath
+		if filepath is not None:
+			self._read_from_file()
+		# END handle filepath
+	
+	def _read_from_file(self):
+		fmap = file_contents_ro_filepath(self._path, stream=False, allow_mmap=True)
+		try:
+			self._deserialize(fmap)
+		finally:
+			fmap.close()
+		#END handle closing of handle
+	
+	#{ Interface
+	
+	@classmethod
+	def from_file(cls, filepath):
+		"""
+		:return: a new RefLog instance containing all entries from the reflog 
+			at the given filepath
+		:param filepath: path to reflog 
+		:raise ValueError: If the file could not be read or was corrupted in some way"""
+		return cls(filepath)
+	
+	@classmethod
+	def path(cls, ref):
+		"""
+		:return: string to absolute path at which the reflog of the given ref 
+			instance would be found. The path is not guaranteed to point to a valid 
+			file though.
+		:param ref: SymbolicReference instance"""
+		return join(ref.repo.git_dir, "logs", to_native_path(ref.path))
+		
+	@classmethod
+	def iter_entries(cls, stream):
+		"""
+		:return: Iterator yielding RefLogEntry instances, one for each line read 
+			sfrom the given stream.
+		:param stream: file-like object containing the revlog in its native format
+			or basestring instance pointing to a file to read"""
+		new_entry = RefLogEntry.from_line
+		if isinstance(stream, basestring):
+			stream = file_contents_ro_filepath(stream)
+		#END handle stream type
+		while True:
+			line = stream.readline()
+			if not line:
+				return
+			yield new_entry(line.strip())
+		#END endless loop
+		
+	@classmethod
+	def entry_at(cls, filepath, index):
+		""":return: RefLogEntry at the given index
+		:param filepath: full path to the index file from which to read the entry
+		:param index: python list compatible index, i.e. it may be negative to 
+			specifiy an entry counted from the end of the list
+			
+		:raise IndexError: If the entry didn't exist
+		
+		.. note:: This method is faster as it only parses the entry at index, skipping
+			all other lines. Nonetheless, the whole file has to be read if 
+			the index is negative
+		"""
+		fp = open(filepath, 'rb')
+		if index < 0:
+			return RefLogEntry.from_line(fp.readlines()[index].strip())
+		else:
+			# read until index is reached
+			for i in xrange(index+1):
+				line = fp.readline()
+				if not line:
+					break
+				#END abort on eof
+			#END handle runup
+			
+			if i != index or not line:
+				raise IndexError
+			#END handle exception
+			
+			return RefLogEntry.from_line(line.strip())
+		#END handle index
+	
+	def to_file(self, filepath):
+		"""Write the contents of the reflog instance to a file at the given filepath.
+		:param filepath: path to file, parent directories are assumed to exist"""
+		lfd = LockedFD(filepath)
+		assure_directory_exists(filepath, is_file=True)
+		
+		fp = lfd.open(write=True, stream=True)
+		try:
+			self._serialize(fp)
+			lfd.commit()
+		except:
+			# on failure it rolls back automatically, but we make it clear
+			lfd.rollback()
+			raise
+		#END handle change
+		
+	@classmethod
+	def append_entry(cls, config_reader, filepath, oldbinsha, newbinsha, message):
+		"""Append a new log entry to the revlog at filepath.
+		
+		:param config_reader: configuration reader of the repository - used to obtain
+			user information. May be None
+		:param filepath: full path to the log file
+		:param oldbinsha: binary sha of the previous commit
+		:param newbinsha: binary sha of the current commit
+		:param message: message describing the change to the reference
+		:param write: If True, the changes will be written right away. Otherwise
+			the change will not be written
+		:return: RefLogEntry objects which was appended to the log
+		:note: As we are append-only, concurrent access is not a problem as we 
+			do not interfere with readers."""
+		if len(oldbinsha) != 20 or len(newbinsha) != 20:
+			raise ValueError("Shas need to be given in binary format")
+		#END handle sha type
+		assure_directory_exists(filepath, is_file=True)
+		entry = RefLogEntry((bin_to_hex(oldbinsha), bin_to_hex(newbinsha), Actor.committer(config_reader), (int(time.time()), time.altzone), message))
+		
+		lf = LockFile(filepath)
+		lf._obtain_lock_or_raise()
+		
+		fd = open(filepath, 'a')
+		try:
+			fd.write(repr(entry))
+		finally:
+			fd.close()
+			lf._release_lock()
+		#END handle write operation
+		
+		return entry
+		
+	def write(self):
+		"""Write this instance's data to the file we are originating from
+		:return: self"""
+		if self._path is None:
+			raise ValueError("Instance was not initialized with a path, use to_file(...) instead")
+		#END assert path
+		self.to_file(self._path)
+		return self
+	
+	#} END interface
+	
+	#{ Serializable Interface
+	def _serialize(self, stream):
+		lm1 = len(self) - 1
+		write = stream.write
+		
+		# write all entries
+		for e in self:
+			write(repr(e))
+		#END for each entry
+	
+	def _deserialize(self, stream):
+		self.extend(self.iter_entries(stream))
+	#} END serializable interface
diff --git a/git/refs/reference.py b/git/refs/reference.py
new file mode 100644
index 00000000..1a745ee9
--- /dev/null
+++ b/git/refs/reference.py
@@ -0,0 +1,84 @@
+from symbolic import SymbolicReference
+import os
+from git.objects import Object
+from git.util import (
+					LazyMixin, 
+					Iterable, 
+					)
+
+from gitdb.util import (
+							isfile,
+							hex_to_bin
+						)
+
+__all__ = ["Reference"]
+
+
+class Reference(SymbolicReference, LazyMixin, Iterable):
+	"""Represents a named reference to any object. Subclasses may apply restrictions though, 
+	i.e. Heads can only point to commits."""
+	__slots__ = tuple()
+	_points_to_commits_only = False
+	_resolve_ref_on_create = True
+	_common_path_default = "refs"
+	
+	def __init__(self, repo, path):
+		"""Initialize this instance
+		:param repo: Our parent repository
+		
+		:param path:
+			Path relative to the .git/ directory pointing to the ref in question, i.e.
+			refs/heads/master"""
+		if not path.startswith(self._common_path_default+'/'):
+			raise ValueError("Cannot instantiate %r from path %s" % ( self.__class__.__name__, path ))
+		super(Reference, self).__init__(repo, path)
+		
+
+	def __str__(self):
+		return self.name
+
+	def set_object(self, object, logmsg = None):
+		"""Special version which checks if the head-log needs an update as well"""
+		oldbinsha = None
+		if logmsg is not None:
+			head = self.repo.head
+			if not head.is_detached and head.ref == self:
+				oldbinsha = self.commit.binsha
+			#END handle commit retrieval
+		#END handle message is set
+		
+		super(Reference, self).set_object(object, logmsg)
+		
+		if oldbinsha is not None:
+			# /* from refs.c in git-source
+			# * Special hack: If a branch is updated directly and HEAD
+			# * points to it (may happen on the remote side of a push
+			# * for example) then logically the HEAD reflog should be
+			# * updated too.
+			# * A generic solution implies reverse symref information,
+			# * but finding all symrefs pointing to the given branch
+			# * would be rather costly for this rare event (the direct
+			# * update of a branch) to be worth it.  So let's cheat and
+			# * check with HEAD only which should cover 99% of all usage
+			# * scenarios (even 100% of the default ones).
+			# */
+			self.repo.head.log_append(oldbinsha, logmsg)
+		#END check if the head
+
+	# NOTE: Don't have to overwrite properties as the will only work without a the log
+
+	@property
+	def name(self):
+		""":return: (shortest) Name of this reference - it may contain path components"""
+		# first two path tokens are can be removed as they are 
+		# refs/heads or refs/tags or refs/remotes
+		tokens = self.path.split('/')
+		if len(tokens) < 3:
+			return self.path		   # could be refs/HEAD
+		return '/'.join(tokens[2:])
+	
+	@classmethod
+	def iter_items(cls, repo, common_path = None):
+		"""Equivalent to SymbolicReference.iter_items, but will return non-detached
+		references as well."""
+		return cls._iter_items(repo, common_path)
diff --git a/git/refs/remote.py b/git/refs/remote.py
new file mode 100644
index 00000000..b7b07d4b
--- /dev/null
+++ b/git/refs/remote.py
@@ -0,0 +1,63 @@
+from head import Head
+from git.util import join_path
+from gitdb.util import join
+
+import os
+
+
+__all__ = ["RemoteReference"]
+
+	
+class RemoteReference(Head):
+	"""Represents a reference pointing to a remote head."""
+	_common_path_default = "refs/remotes"
+	
+	
+	@classmethod
+	def iter_items(cls, repo, common_path = None, remote=None):
+		"""Iterate remote references, and if given, constrain them to the given remote"""
+		common_path = common_path or cls._common_path_default
+		if remote is not None:
+			common_path = join_path(common_path, str(remote))
+		# END handle remote constraint
+		return super(RemoteReference, cls).iter_items(repo, common_path)
+	
+	@property
+	def remote_name(self):
+		"""
+		:return:
+			Name of the remote we are a reference of, such as 'origin' for a reference
+			named 'origin/master'"""
+		tokens = self.path.split('/')
+		# /refs/remotes/<remote name>/<branch_name>
+		return tokens[2]
+		
+	@property
+	def remote_head(self):
+		""":return: Name of the remote head itself, i.e. master.
+		:note: The returned name is usually not qualified enough to uniquely identify
+			a branch"""
+		tokens = self.path.split('/')
+		return '/'.join(tokens[3:])
+		
+	@classmethod
+	def delete(cls, repo, *refs, **kwargs):
+		"""Delete the given remote references.
+		:note:
+			kwargs are given for compatability with the base class method as we 
+			should not narrow the signature."""
+		repo.git.branch("-d", "-r", *refs)
+		# the official deletion method will ignore remote symbolic refs - these 
+		# are generally ignored in the refs/ folder. We don't though 
+		# and delete remainders manually
+		for ref in refs:
+			try:
+				os.remove(join(repo.git_dir, ref.path))
+			except OSError:
+				pass
+		# END for each ref
+		
+	@classmethod
+	def create(cls, *args, **kwargs):
+		"""Used to disable this method"""
+		raise TypeError("Cannot explicitly create remote references")
diff --git a/git/refs/symbolic.py b/git/refs/symbolic.py
new file mode 100644
index 00000000..9937cf0c
--- /dev/null
+++ b/git/refs/symbolic.py
@@ -0,0 +1,618 @@
+import os
+from git.objects import Object, Commit
+from git.util import (
+					join_path, 
+					join_path_native, 
+					to_native_path_linux,
+					assure_directory_exists
+					)
+
+from gitdb.exc import BadObject
+from gitdb.util import (
+							join, 
+							dirname,
+							isdir,
+							exists,
+							isfile,
+							rename,
+							hex_to_bin,
+							LockedFD
+						)
+
+from log import RefLog
+
+__all__ = ["SymbolicReference"]
+
+class SymbolicReference(object):
+	"""Represents a special case of a reference such that this reference is symbolic.
+	It does not point to a specific commit, but to another Head, which itself 
+	specifies a commit.
+	
+	A typical example for a symbolic reference is HEAD."""
+	__slots__ = ("repo", "path")
+	_resolve_ref_on_create = False
+	_points_to_commits_only = True
+	_common_path_default = ""
+	_id_attribute_ = "name"
+	
+	def __init__(self, repo, path):
+		self.repo = repo
+		self.path = path
+		
+	def __str__(self):
+		return self.path
+		
+	def __repr__(self):
+		return '<git.%s "%s">' % (self.__class__.__name__, self.path)
+		
+	def __eq__(self, other):
+		return self.path == other.path
+		
+	def __ne__(self, other):
+		return not ( self == other )
+		
+	def __hash__(self):
+		return hash(self.path)
+		
+	@property
+	def name(self):
+		"""
+		:return:
+			In case of symbolic references, the shortest assumable name 
+			is the path itself."""
+		return self.path
+	
+	@property
+	def abspath(self):
+		return join_path_native(self.repo.git_dir, self.path)
+		
+	@classmethod
+	def _get_packed_refs_path(cls, repo):
+		return join(repo.git_dir, 'packed-refs')
+		
+	@classmethod
+	def _iter_packed_refs(cls, repo):
+		"""Returns an iterator yielding pairs of sha1/path pairs for the corresponding refs.
+		:note: The packed refs file will be kept open as long as we iterate"""
+		try:
+			fp = open(cls._get_packed_refs_path(repo), 'r')
+			for line in fp:
+				line = line.strip()
+				if not line:
+					continue
+				if line.startswith('#'):
+					if line.startswith('# pack-refs with:') and not line.endswith('peeled'):
+						raise TypeError("PackingType of packed-Refs not understood: %r" % line)
+					# END abort if we do not understand the packing scheme
+					continue
+				# END parse comment
+				
+				# skip dereferenced tag object entries - previous line was actual
+				# tag reference for it
+				if line[0] == '^':
+					continue
+				
+				yield tuple(line.split(' ', 1))
+			# END for each line
+		except (OSError,IOError):
+			raise StopIteration
+		# END no packed-refs file handling 
+		# NOTE: Had try-finally block around here to close the fp, 
+		# but some python version woudn't allow yields within that.
+		# I believe files are closing themselves on destruction, so it is 
+		# alright.
+		
+	@classmethod
+	def dereference_recursive(cls, repo, ref_path):
+		"""
+		:return: hexsha stored in the reference at the given ref_path, recursively dereferencing all
+			intermediate references as required
+		:param repo: the repository containing the reference at ref_path"""
+		while True:
+			hexsha, ref_path = cls._get_ref_info(repo, ref_path)
+			if hexsha is not None:
+				return hexsha
+		# END recursive dereferencing
+		
+	@classmethod
+	def _get_ref_info(cls, repo, ref_path):
+		"""Return: (sha, target_ref_path) if available, the sha the file at 
+		rela_path points to, or None. target_ref_path is the reference we 
+		point to, or None"""
+		tokens = None
+		try:
+			fp = open(join(repo.git_dir, ref_path), 'r')
+			value = fp.read().rstrip()
+			fp.close()
+			tokens = value.split(" ")
+		except (OSError,IOError):
+			# Probably we are just packed, find our entry in the packed refs file
+			# NOTE: We are not a symbolic ref if we are in a packed file, as these
+			# are excluded explictly
+			for sha, path in cls._iter_packed_refs(repo):
+				if path != ref_path: continue
+				tokens = (sha, path)
+				break
+			# END for each packed ref
+		# END handle packed refs
+		if tokens is None:
+			raise ValueError("Reference at %r does not exist" % ref_path)
+		
+		# is it a reference ?
+		if tokens[0] == 'ref:':
+			return (None, tokens[1])
+			
+		# its a commit
+		if repo.re_hexsha_only.match(tokens[0]):
+			return (tokens[0], None)
+			
+		raise ValueError("Failed to parse reference information from %r" % ref_path)
+	
+	def _get_object(self):
+		"""
+		:return:
+			The object our ref currently refers to. Refs can be cached, they will 
+			always point to the actual object as it gets re-created on each query"""
+		# have to be dynamic here as we may be a tag which can point to anything
+		# Our path will be resolved to the hexsha which will be used accordingly
+		return Object.new_from_sha(self.repo, hex_to_bin(self.dereference_recursive(self.repo, self.path)))
+	
+	def _get_commit(self):
+		"""
+		:return:
+			Commit object we point to, works for detached and non-detached 
+			SymbolicReferences. The symbolic reference will be dereferenced recursively."""
+		obj = self._get_object()
+		if obj.type == 'tag':
+			obj = obj.object
+		#END dereference tag
+		
+		if obj.type != Commit.type:
+			raise TypeError("Symbolic Reference pointed to object %r, commit was required" % obj)
+		#END handle type
+		return obj
+		
+	def set_commit(self, commit, logmsg = None):
+		"""As set_object, but restricts the type of object to be a Commit
+		
+		:raise ValueError: If commit is not a Commit object or doesn't point to 
+			a commit
+		:return: self"""
+		# check the type - assume the best if it is a base-string
+		invalid_type = False
+		if isinstance(commit, Object):
+			invalid_type = commit.type != Commit.type
+		elif isinstance(commit, SymbolicReference):
+			invalid_type = commit.object.type != Commit.type
+		else:
+			try:
+				invalid_type = self.repo.rev_parse(commit).type != Commit.type
+			except BadObject:
+				raise ValueError("Invalid object: %s" % commit)
+			#END handle exception
+		# END verify type
+		
+		if invalid_type:
+			raise ValueError("Need commit, got %r" % commit)
+		#END handle raise
+		
+		# we leave strings to the rev-parse method below
+		self.set_object(commit, logmsg)
+		
+		return self
+		
+	
+	def set_object(self, object, logmsg = None):
+		"""Set the object we point to, possibly dereference our symbolic reference first.
+		If the reference does not exist, it will be created
+		
+		:param object: a refspec, a SymbolicReference or an Object instance. SymbolicReferences
+			will be dereferenced beforehand to obtain the object they point to
+		:param logmsg: If not None, the message will be used in the reflog entry to be 
+			written. Otherwise the reflog is not altered
+		:note: plain SymbolicReferences may not actually point to objects by convention
+		:return: self"""
+		if isinstance(object, SymbolicReference):
+			object = object.object
+		#END resolve references
+		
+		is_detached = True
+		try:
+			is_detached = self.is_detached
+		except ValueError:
+			pass
+		# END handle non-existing ones
+		
+		if is_detached:
+			return self.set_reference(object, logmsg)
+			
+		# set the commit on our reference
+		return self._get_reference().set_object(object, logmsg)
+	
+	commit = property(_get_commit, set_commit, doc="Query or set commits directly")
+	object = property(_get_object, set_object, doc="Return the object our ref currently refers to")
+		
+	def _get_reference(self):
+		""":return: Reference Object we point to
+		:raise TypeError: If this symbolic reference is detached, hence it doesn't point
+			to a reference, but to a commit"""
+		sha, target_ref_path = self._get_ref_info(self.repo, self.path)
+		if target_ref_path is None:
+			raise TypeError("%s is a detached symbolic reference as it points to %r" % (self, sha))
+		return self.from_path(self.repo, target_ref_path)
+		
+	def set_reference(self, ref, logmsg = None):
+		"""Set ourselves to the given ref. It will stay a symbol if the ref is a Reference.
+		Otherwise an Object, given as Object instance or refspec, is assumed and if valid, 
+		will be set which effectively detaches the refererence if it was a purely 
+		symbolic one.
+		
+		:param ref: SymbolicReference instance, Object instance or refspec string
+			Only if the ref is a SymbolicRef instance, we will point to it. Everthiny
+			else is dereferenced to obtain the actual object.
+		:param logmsg: If set to a string, the message will be used in the reflog.
+			Otherwise, a reflog entry is not written for the changed reference.
+			The previous commit of the entry will be the commit we point to now.
+			
+			See also: log_append()
+		
+		:return: self
+		:note: This symbolic reference will not be dereferenced. For that, see 
+			``set_object(...)``"""
+		write_value = None
+		obj = None
+		if isinstance(ref, SymbolicReference):
+			write_value = "ref: %s" % ref.path
+		elif isinstance(ref, Object):
+			obj = ref
+			write_value = ref.hexsha
+		elif isinstance(ref, basestring):
+			try:
+				obj = self.repo.rev_parse(ref+"^{}")	# optionally deref tags
+				write_value = obj.hexsha
+			except BadObject:
+				raise ValueError("Could not extract object from %s" % ref)
+			# END end try string
+		else:
+			raise ValueError("Unrecognized Value: %r" % ref)
+		# END try commit attribute
+		
+		# typecheck
+		if obj is not None and self._points_to_commits_only and obj.type != Commit.type:
+			raise TypeError("Require commit, got %r" % obj)
+		#END verify type
+		
+		oldbinsha = None
+		if logmsg is not None:
+			try:
+				oldbinsha = self.commit.binsha
+			except ValueError:
+				oldbinsha = Commit.NULL_BIN_SHA
+			#END handle non-existing
+		#END retrieve old hexsha
+		
+		fpath = self.abspath
+		assure_directory_exists(fpath, is_file=True)
+		
+		lfd = LockedFD(fpath)
+		fd = lfd.open(write=True, stream=True)
+		fd.write(write_value)
+		lfd.commit()
+		
+		# Adjust the reflog
+		if logmsg is not None:
+			self.log_append(oldbinsha, logmsg)
+		#END handle reflog
+		
+		return self
+		
+
+	# aliased reference
+	reference = property(_get_reference, set_reference, doc="Returns the Reference we point to")
+	ref = reference
+	
+	def is_valid(self):
+		"""
+		:return:
+			True if the reference is valid, hence it can be read and points to 
+			a valid object or reference."""
+		try:
+			self.object
+		except (OSError, ValueError):
+			return False
+		else:
+			return True
+		
+	@property
+	def is_detached(self):
+		"""
+		:return:
+			True if we are a detached reference, hence we point to a specific commit
+			instead to another reference"""
+		try:
+			self.ref
+			return False
+		except TypeError:
+			return True
+	
+	def log(self):
+		"""
+		:return: RefLog for this reference. Its last entry reflects the latest change
+			applied to this reference
+			
+		.. note:: As the log is parsed every time, its recommended to cache it for use
+			instead of calling this method repeatedly. It should be considered read-only."""
+		return RefLog.from_file(RefLog.path(self))
+		
+	def log_append(self, oldbinsha, message, newbinsha=None):
+		"""Append a logentry to the logfile of this ref
+		
+		:param oldbinsha: binary sha this ref used to point to
+		:param message: A message describing the change
+		:param newbinsha: The sha the ref points to now. If None, our current commit sha
+			will be used
+		:return: added RefLogEntry instance"""
+		return RefLog.append_entry(self.repo.config_reader(), RefLog.path(self), oldbinsha, 
+									(newbinsha is None and self.commit.binsha) or newbinsha, 
+									message) 
+
+	def log_entry(self, index):
+		""":return: RefLogEntry at the given index
+		:param index: python list compatible positive or negative index
+		
+		.. note:: This method must read part of the reflog during execution, hence 
+			it should be used sparringly, or only if you need just one index.
+			In that case, it will be faster than the ``log()`` method"""
+		return RefLog.entry_at(RefLog.path(self), index)
+
+	@classmethod
+	def to_full_path(cls, path):
+		"""
+		:return: string with a full repository-relative path which can be used to initialize 
+			a Reference instance, for instance by using ``Reference.from_path``"""
+		if isinstance(path, SymbolicReference):
+			path = path.path
+		full_ref_path = path
+		if not cls._common_path_default:
+			return full_ref_path
+		if not path.startswith(cls._common_path_default+"/"):
+			full_ref_path = '%s/%s' % (cls._common_path_default, path)
+		return full_ref_path
+	
+	@classmethod
+	def delete(cls, repo, path):
+		"""Delete the reference at the given path
+		
+		:param repo:
+			Repository to delete the reference from
+		
+		:param path:
+			Short or full path pointing to the reference, i.e. refs/myreference
+			or just "myreference", hence 'refs/' is implied.
+			Alternatively the symbolic reference to be deleted"""
+		full_ref_path = cls.to_full_path(path)
+		abs_path = join(repo.git_dir, full_ref_path)
+		if exists(abs_path):
+			os.remove(abs_path)
+		else:
+			# check packed refs
+			pack_file_path = cls._get_packed_refs_path(repo)
+			try:
+				reader = open(pack_file_path)
+			except (OSError,IOError):
+				pass # it didnt exist at all
+			else:
+				new_lines = list()
+				made_change = False
+				dropped_last_line = False
+				for line in reader:
+					# keep line if it is a comment or if the ref to delete is not 
+					# in the line
+					# If we deleted the last line and this one is a tag-reference object, 
+					# we drop it as well
+					if ( line.startswith('#') or full_ref_path not in line ) and \
+						( not dropped_last_line or dropped_last_line and not line.startswith('^') ):
+						new_lines.append(line)
+						dropped_last_line = False
+						continue
+					# END skip comments and lines without our path
+					
+					# drop this line
+					made_change = True
+					dropped_last_line = True
+				# END for each line in packed refs
+				reader.close()
+				
+				# write the new lines
+				if made_change:
+					open(pack_file_path, 'w').writelines(new_lines)
+			# END open exception handling
+		# END handle deletion
+		
+		# delete the reflog
+		reflog_path = RefLog.path(cls(repo, full_ref_path))
+		if os.path.isfile(reflog_path):
+			os.remove(reflog_path)
+		#END remove reflog
+		
+			
+	@classmethod
+	def _create(cls, repo, path, resolve, reference, force, logmsg=None):
+		"""internal method used to create a new symbolic reference.
+		If resolve is False, the reference will be taken as is, creating 
+		a proper symbolic reference. Otherwise it will be resolved to the 
+		corresponding object and a detached symbolic reference will be created
+		instead"""
+		full_ref_path = cls.to_full_path(path)
+		abs_ref_path = join(repo.git_dir, full_ref_path)
+		
+		# figure out target data
+		target = reference
+		if resolve:
+			target = repo.rev_parse(str(reference))
+			
+		if not force and isfile(abs_ref_path):
+			target_data = str(target)
+			if isinstance(target, SymbolicReference):
+				target_data = target.path
+			if not resolve:
+				target_data = "ref: " + target_data
+			existing_data = open(abs_ref_path, 'rb').read().strip() 
+			if existing_data != target_data:
+				raise OSError("Reference at %r does already exist, pointing to %r, requested was %r" % (full_ref_path, existing_data, target_data))
+		# END no force handling
+		
+		ref = cls(repo, full_ref_path)
+		ref.set_reference(target, logmsg)
+		return ref
+		
+	@classmethod
+	def create(cls, repo, path, reference='HEAD', force=False, logmsg=None):
+		"""Create a new symbolic reference, hence a reference pointing to another reference.
+		
+		:param repo:
+			Repository to create the reference in 
+			
+		:param path:
+			full path at which the new symbolic reference is supposed to be 
+			created at, i.e. "NEW_HEAD" or "symrefs/my_new_symref"
+			
+		:param reference:
+			The reference to which the new symbolic reference should point to
+		
+		:param force:
+			if True, force creation even if a symbolic reference with that name already exists.
+			Raise OSError otherwise
+			
+		:param logmsg:
+			If not None, the message to append to the reflog. Otherwise no reflog
+			entry is written.
+			
+		:return: Newly created symbolic Reference
+			
+		:raise OSError:
+			If a (Symbolic)Reference with the same name but different contents
+			already exists.
+		
+		:note: This does not alter the current HEAD, index or Working Tree"""
+		return cls._create(repo, path, cls._resolve_ref_on_create, reference, force, logmsg)
+	
+	def rename(self, new_path, force=False):
+		"""Rename self to a new path
+		
+		:param new_path:
+			Either a simple name or a full path, i.e. new_name or features/new_name.
+			The prefix refs/ is implied for references and will be set as needed.
+			In case this is a symbolic ref, there is no implied prefix
+			
+		:param force:
+			If True, the rename will succeed even if a head with the target name
+			already exists. It will be overwritten in that case
+			
+		:return: self
+		:raise OSError: In case a file at path but a different contents already exists """
+		new_path = self.to_full_path(new_path)
+		if self.path == new_path:
+			return self
+		
+		new_abs_path = join(self.repo.git_dir, new_path)
+		cur_abs_path = join(self.repo.git_dir, self.path)
+		if isfile(new_abs_path):
+			if not force:
+				# if they point to the same file, its not an error
+				if open(new_abs_path,'rb').read().strip() != open(cur_abs_path,'rb').read().strip():
+					raise OSError("File at path %r already exists" % new_abs_path)
+				# else: we could remove ourselves and use the otherone, but 
+				# but clarity we just continue as usual
+			# END not force handling
+			os.remove(new_abs_path)
+		# END handle existing target file
+		
+		dname = dirname(new_abs_path)
+		if not isdir(dname):
+			os.makedirs(dname)
+		# END create directory
+		
+		rename(cur_abs_path, new_abs_path)
+		self.path = new_path
+		
+		return self
+		
+	@classmethod
+	def _iter_items(cls, repo, common_path = None):
+		if common_path is None:
+			common_path = cls._common_path_default
+		rela_paths = set()
+		
+		# walk loose refs
+		# Currently we do not follow links 
+		for root, dirs, files in os.walk(join_path_native(repo.git_dir, common_path)):
+			if 'refs/' not in root: # skip non-refs subfolders
+				refs_id = [ i for i,d in enumerate(dirs) if d == 'refs' ]
+				if refs_id:
+					dirs[0:] = ['refs']
+			# END prune non-refs folders
+			
+			for f in files:
+				abs_path = to_native_path_linux(join_path(root, f))
+				rela_paths.add(abs_path.replace(to_native_path_linux(repo.git_dir) + '/', ""))
+			# END for each file in root directory
+		# END for each directory to walk
+		
+		# read packed refs
+		for sha, rela_path in cls._iter_packed_refs(repo):
+			if rela_path.startswith(common_path):
+				rela_paths.add(rela_path)
+			# END relative path matches common path
+		# END packed refs reading
+		
+		# return paths in sorted order
+		for path in sorted(rela_paths):
+			try:
+				yield cls.from_path(repo, path)
+			except ValueError:
+				continue
+		# END for each sorted relative refpath
+		
+	@classmethod
+	def iter_items(cls, repo, common_path = None):
+		"""Find all refs in the repository
+
+		:param repo: is the Repo
+
+		:param common_path:
+			Optional keyword argument to the path which is to be shared by all
+			returned Ref objects.
+			Defaults to class specific portion if None assuring that only 
+			refs suitable for the actual class are returned.
+
+		:return:
+			git.SymbolicReference[], each of them is guaranteed to be a symbolic
+			ref which is not detached.
+			
+			List is lexigraphically sorted
+			The returned objects represent actual subclasses, such as Head or TagReference"""
+		return ( r for r in cls._iter_items(repo, common_path) if r.__class__ == SymbolicReference or not r.is_detached )
+		
+	@classmethod
+	def from_path(cls, repo, path):
+		"""
+		:param path: full .git-directory-relative path name to the Reference to instantiate
+		:note: use to_full_path() if you only have a partial path of a known Reference Type
+		:return:
+			Instance of type Reference, Head, or Tag
+			depending on the given path"""
+		if not path:
+			raise ValueError("Cannot create Reference from %r" % path)
+		
+		for ref_type in (HEAD, Head, RemoteReference, TagReference, Reference, SymbolicReference):
+			try:
+				instance = ref_type(repo, path)
+				if instance.__class__ == SymbolicReference and instance.is_detached:
+					raise ValueError("SymbolRef was detached, we drop it")
+				return instance
+			except ValueError:
+				pass
+			# END exception handling
+		# END for each type to try
+		raise ValueError("Could not find reference type suitable to handle path %r" % path)
diff --git a/git/refs/tag.py b/git/refs/tag.py
new file mode 100644
index 00000000..c09d814d
--- /dev/null
+++ b/git/refs/tag.py
@@ -0,0 +1,91 @@
+from reference import Reference
+
+__all__ = ["TagReference", "Tag"]
+
+
+	
+class TagReference(Reference):
+	"""Class representing a lightweight tag reference which either points to a commit 
+	,a tag object or any other object. In the latter case additional information, 
+	like the signature or the tag-creator, is available.
+	
+	This tag object will always point to a commit object, but may carray additional
+	information in a tag object::
+	
+	 tagref = TagReference.list_items(repo)[0]
+	 print tagref.commit.message
+	 if tagref.tag is not None:
+		print tagref.tag.message"""
+	
+	__slots__ = tuple()
+	_common_path_default = "refs/tags"
+	
+	@property
+	def commit(self):
+		""":return: Commit object the tag ref points to"""
+		obj = self.object
+		if obj.type == "commit":
+			return obj
+		elif obj.type == "tag":
+			# it is a tag object which carries the commit as an object - we can point to anything
+			return obj.object
+		else:
+			raise ValueError( "Tag %s points to a Blob or Tree - have never seen that before" % self )	
+
+	@property
+	def tag(self):
+		"""
+		:return: Tag object this tag ref points to or None in case 
+			we are a light weight tag"""
+		obj = self.object
+		if obj.type == "tag":
+			return obj
+		return None
+		
+	# make object read-only
+	# It should be reasonably hard to adjust an existing tag
+	object = property(Reference._get_object)
+		
+	@classmethod
+	def create(cls, repo, path, ref='HEAD', message=None, force=False, **kwargs):
+		"""Create a new tag reference.
+		
+		:param path:
+			The name of the tag, i.e. 1.0 or releases/1.0. 
+			The prefix refs/tags is implied
+			
+		:param ref:
+			A reference to the object you want to tag. It can be a commit, tree or 
+			blob.
+			
+		:param message:
+			If not None, the message will be used in your tag object. This will also 
+			create an additional tag object that allows to obtain that information, i.e.::
+			
+				tagref.tag.message
+			
+		:param force:
+			If True, to force creation of a tag even though that tag already exists.
+			
+		:param kwargs:
+			Additional keyword arguments to be passed to git-tag
+			
+		:return: A new TagReference"""
+		args = ( path, ref )
+		if message:
+			kwargs['m'] =  message
+		if force:
+			kwargs['f'] = True
+		
+		repo.git.tag(*args, **kwargs)
+		return TagReference(repo, "%s/%s" % (cls._common_path_default, path))
+		
+	@classmethod
+	def delete(cls, repo, *tags):
+		"""Delete the given existing tag or tags"""
+		repo.git.tag("-d", *tags)
+		
+		
+		
+# provide an alias
+Tag = TagReference