xattr: centralize the various shims in one place

Rather than each module implementing its own shim around the various
methods for accessing extended attributes, start a dedicated module
that exports a consistent API.

7 files changed, 441 insertions, 118 deletions

diff --git a/bin/quickpkg b/bin/quickpkg
index 726abffa3..262fda4ab 100755
--- a/bin/quickpkg
+++ b/bin/quickpkg
@@ -21,8 +21,8 @@ from portage.dbapi.dep_expand import dep_expand
 from portage.dep import Atom, use_reduce
 from portage.exception import (AmbiguousPackageName, InvalidAtom, InvalidData,
 	InvalidDependString, PackageSetNotFound, PermissionDenied)
-from portage.util import ConfigProtect, ensure_dirs, shlex_split
-import portage.util.xattr as _xattr
+from portage.util import ConfigProtect, ensure_dirs, shlex_split, _xattr
+xattr = _xattr.xattr
 from portage.dbapi.vartree import dblink, tar_contents
 from portage.checksum import perform_md5
 from portage._sets import load_default_config, SETPREFIX
@@ -36,7 +36,7 @@ def quickpkg_atom(options, infos, arg, eout):
 	vartree = trees["vartree"]
 	vardb = vartree.dbapi
 	bintree = trees["bintree"]
-	xattr = 'xattr' in settings.features
+	xattrs = 'xattr' in settings.features
 
 	include_config = options.include_config == "y"
 	include_unmodified_config = options.include_unmodified_config == "y"
@@ -137,8 +137,8 @@ def quickpkg_atom(options, infos, arg, eout):
 			# The tarfile module will write pax headers holding the
 			# xattrs only if PAX_FORMAT is specified here.
 			tar = tarfile.open(binpkg_tmpfile, "w:bz2",
-				format=tarfile.PAX_FORMAT if xattr else tarfile.DEFAULT_FORMAT)
-			tar_contents(contents, root, tar, protect=protect, xattr=xattr)
+				format=tarfile.PAX_FORMAT if xattrs else tarfile.DEFAULT_FORMAT)
+			tar_contents(contents, root, tar, protect=protect, xattrs=xattrs)
 			tar.close()
 			xpak.tbz2(binpkg_tmpfile).recompose_mem(xpdata)
 		finally:
@@ -238,7 +238,7 @@ def quickpkg_main(options, args, eout):
 		eout.eerror("No write access to '%s'" % bintree.pkgdir)
 		return errno.EACCES
 
-	if 'xattr' in portage.settings.features and not hasattr(_xattr, 'getxattr'):
+	if 'xattr' in portage.settings.features and not _xattr.XATTRS_WORKS:
 		eout.eerror("No xattr support library was found, "
 			"so xattrs will not be preserved!")
 		portage.settings.unlock()
diff --git a/bin/xattr-helper.py b/bin/xattr-helper.py
index 3e9b81eaf..19f25f92d 100755
--- a/bin/xattr-helper.py
+++ b/bin/xattr-helper.py
@@ -19,16 +19,7 @@ import re
 import sys
 
 from portage.util._argparse import ArgumentParser
-
-if hasattr(os, "getxattr"):
-
-	class xattr(object):
-		get = os.getxattr
-		set = os.setxattr
-		list = os.listxattr
-
-else:
-	import xattr
+from portage.util._xattr import xattr
 
 
 _UNQUOTE_RE = re.compile(br'\\[0-7]{3}')
diff --git a/pym/portage/dbapi/vartree.py b/pym/portage/dbapi/vartree.py
index 927c64549..5ba8d9d34 100644
--- a/pym/portage/dbapi/vartree.py
+++ b/pym/portage/dbapi/vartree.py
@@ -35,7 +35,7 @@ portage.proxy.lazyimport.lazyimport(globals(),
 	'portage.util.movefile:movefile',
 	'portage.util.path:first_existing,iter_parents',
 	'portage.util.writeable_check:get_ro_checker',
-	'portage.util:xattr@_xattr',
+	'portage.util._xattr:xattr',
 	'portage.util._dyn_libs.PreservedLibsRegistry:PreservedLibsRegistry',
 	'portage.util._dyn_libs.LinkageMapELF:LinkageMapELF@LinkageMap',
 	'portage.util._async.SchedulerInterface:SchedulerInterface',
@@ -5268,7 +5268,7 @@ def write_contents(contents, root, f):
 		f.write(line)
 
 def tar_contents(contents, root, tar, protect=None, onProgress=None,
-	xattr=False):
+	xattrs=False):
 	os = _os_merge
 	encoding = _encodings['merge']
 
@@ -5390,13 +5390,13 @@ def tar_contents(contents, root, tar, protect=None, onProgress=None,
 					encoding=encoding,
 					errors='strict')
 
-				if xattr:
+				if xattrs:
 					# Compatible with GNU tar, which saves the xattrs
 					# under the SCHILY.xattr namespace.
-					for k in _xattr.listxattr(path_bytes):
+					for k in xattr.list(path_bytes):
 						tarinfo.pax_headers['SCHILY.xattr.' +
 							_unicode_decode(k)] = _unicode_decode(
-							_xattr.getxattr(path_bytes, _unicode_encode(k)))
+							xattr.get(path_bytes, _unicode_encode(k)))
 
 				with open(path_bytes, 'rb') as f:
 					tar.addfile(tarinfo, f)
diff --git a/pym/portage/tests/util/test_xattr.py b/pym/portage/tests/util/test_xattr.py
new file mode 100644
index 000000000..2e2564a6e
--- /dev/null
+++ b/pym/portage/tests/util/test_xattr.py
@@ -0,0 +1,178 @@
+# Copyright 2010-2015 Gentoo Foundation
+# Distributed under the terms of the GNU General Public License v2
+
+"""Tests for the portage.util._xattr module"""
+
+from __future__ import print_function
+
+try:
+	# Try python-3.3 module first.
+	# pylint: disable=no-name-in-module
+	from unittest import mock
+except ImportError:
+	try:
+		# Try standalone module.
+		import mock
+	except ImportError:
+		mock = None
+
+import subprocess
+
+import portage
+from portage.tests import TestCase
+from portage.util._xattr import (xattr as _xattr, _XattrSystemCommands,
+                                 _XattrStub)
+
+
+orig_popen = subprocess.Popen
+def MockSubprocessPopen(stdin):
+	"""Helper to mock (closely) a subprocess.Popen call
+
+	The module has minor tweaks in behavior when it comes to encoding and
+	python versions, so use a real subprocess.Popen call to fake out the
+	runtime behavior.  This way we don't have to also implement different
+	encodings as that gets ugly real fast.
+	"""
+	# pylint: disable=protected-access
+	proc = orig_popen(['cat'], stdout=subprocess.PIPE, stdin=subprocess.PIPE)
+	proc.stdin.write(portage._unicode_encode(stdin, portage._encodings['stdio']))
+	return proc
+
+
+class SystemCommandsTest(TestCase):
+	"""Test _XattrSystemCommands"""
+
+	OUTPUT = '\n'.join((
+		'# file: /bin/ping',
+		'security.capability=0sAQAAAgAgAAAAAAAAAAAAAAAAAAA=',
+		'user.foo="asdf"',
+		'',
+	))
+
+	def _setUp(self):
+		if mock is None:
+			self.skipTest('need mock for testing')
+
+		return _XattrSystemCommands
+
+	def _testGetBasic(self):
+		"""Verify the get() behavior"""
+		xattr = self._setUp()
+		with mock.patch.object(subprocess, 'Popen') as call_mock:
+			# Verify basic behavior, and namespace arg works as expected.
+			xattr.get('/some/file', 'user.foo')
+			xattr.get('/some/file', 'foo', namespace='user')
+			self.assertEqual(call_mock.call_args_list[0], call_mock.call_args_list[1])
+
+			# Verify nofollow behavior.
+			call_mock.reset()
+			xattr.get('/some/file', 'user.foo', nofollow=True)
+			self.assertIn('-h', call_mock.call_args[0][0])
+
+	def testGetParsing(self):
+		"""Verify get() parses output sanely"""
+		xattr = self._setUp()
+		with mock.patch.object(subprocess, 'Popen') as call_mock:
+			# Verify output parsing.
+			call_mock.return_value = MockSubprocessPopen('\n'.join([
+				'# file: /some/file',
+				'user.foo="asdf"',
+				'',
+			]))
+			call_mock.reset()
+			self.assertEqual(xattr.get('/some/file', 'user.foo'), b'"asdf"')
+
+	def testGetAllBasic(self):
+		"""Verify the get_all() behavior"""
+		xattr = self._setUp()
+		with mock.patch.object(subprocess, 'Popen') as call_mock:
+			# Verify basic behavior.
+			xattr.get_all('/some/file')
+
+			# Verify nofollow behavior.
+			call_mock.reset()
+			xattr.get_all('/some/file', nofollow=True)
+			self.assertIn('-h', call_mock.call_args[0][0])
+
+	def testGetAllParsing(self):
+		"""Verify get_all() parses output sanely"""
+		xattr = self._setUp()
+		with mock.patch.object(subprocess, 'Popen') as call_mock:
+			# Verify output parsing.
+			call_mock.return_value = MockSubprocessPopen(self.OUTPUT)
+			exp = [
+				(b'security.capability', b'0sAQAAAgAgAAAAAAAAAAAAAAAAAAA='),
+				(b'user.foo', b'"asdf"'),
+			]
+			self.assertEqual(exp, xattr.get_all('/some/file'))
+
+	def testSetBasic(self):
+		"""Verify the set() behavior"""
+		xattr = self._setUp()
+		with mock.patch.object(subprocess, 'Popen') as call_mock:
+			# Verify basic behavior, and namespace arg works as expected.
+			xattr.set('/some/file', 'user.foo', 'bar')
+			xattr.set('/some/file', 'foo', 'bar', namespace='user')
+			self.assertEqual(call_mock.call_args_list[0], call_mock.call_args_list[1])
+
+	def testListBasic(self):
+		"""Verify the list() behavior"""
+		xattr = self._setUp()
+		with mock.patch.object(subprocess, 'Popen') as call_mock:
+			# Verify basic behavior.
+			xattr.list('/some/file')
+
+			# Verify nofollow behavior.
+			call_mock.reset()
+			xattr.list('/some/file', nofollow=True)
+			self.assertIn('-h', call_mock.call_args[0][0])
+
+	def testListParsing(self):
+		"""Verify list() parses output sanely"""
+		xattr = self._setUp()
+		with mock.patch.object(subprocess, 'Popen') as call_mock:
+			# Verify output parsing.
+			call_mock.return_value = MockSubprocessPopen(self.OUTPUT)
+			exp = [b'security.capability', b'user.foo']
+			self.assertEqual(exp, xattr.list('/some/file'))
+
+	def testRemoveBasic(self):
+		"""Verify the remove() behavior"""
+		xattr = self._setUp()
+		with mock.patch.object(subprocess, 'Popen') as call_mock:
+			# Verify basic behavior, and namespace arg works as expected.
+			xattr.remove('/some/file', 'user.foo')
+			xattr.remove('/some/file', 'foo', namespace='user')
+			self.assertEqual(call_mock.call_args_list[0], call_mock.call_args_list[1])
+
+			# Verify nofollow behavior.
+			call_mock.reset()
+			xattr.remove('/some/file', 'user.foo', nofollow=True)
+			self.assertIn('-h', call_mock.call_args[0][0])
+
+
+class StubTest(TestCase):
+	"""Test _XattrStub"""
+
+	def testBasic(self):
+		"""Verify the stub is stubby"""
+		# Would be nice to verify raised errno is OperationNotSupported.
+		self.assertRaises(OSError, _XattrStub.get, '/', '')
+		self.assertRaises(OSError, _XattrStub.set, '/', '', '')
+		self.assertRaises(OSError, _XattrStub.get_all, '/')
+		self.assertRaises(OSError, _XattrStub.remove, '/', '')
+		self.assertRaises(OSError, _XattrStub.list, '/')
+
+
+class StandardTest(TestCase):
+	"""Test basic xattr API"""
+
+	MODULES = (_xattr, _XattrSystemCommands, _XattrStub)
+	FUNCS = ('get', 'get_all', 'set', 'remove', 'list')
+
+	def testApi(self):
+		"""Make sure the exported API matches"""
+		for mod in self.MODULES:
+			for f in self.FUNCS:
+				self.assertTrue(hasattr(mod, f),
+					'%s func missing in %s' % (f, mod))
diff --git a/pym/portage/util/_xattr.py b/pym/portage/util/_xattr.py
new file mode 100644
index 000000000..9a8704d70
--- /dev/null
+++ b/pym/portage/util/_xattr.py
@@ -0,0 +1,228 @@
+# Copyright 2010-2015 Gentoo Foundation
+# Distributed under the terms of the GNU General Public License v2
+
+"""Portability shim for xattr support
+
+Exported API is the xattr object with get/get_all/set/remove/list operations.
+We do not include the functions that Python 3.3+ provides in the os module as
+the signature there is different compared to xattr.
+
+See the standard xattr module for more documentation:
+	https://pypi.python.org/pypi/pyxattr
+"""
+
+from __future__ import print_function
+
+import contextlib
+import os
+import subprocess
+
+from portage.exception import OperationNotSupported
+
+
+class _XattrGetAll(object):
+	"""Implement get_all() using list()/get() if there is no easy bulk method"""
+
+	@classmethod
+	def get_all(cls, item, nofollow=False, namespace=None):
+		return [(name, cls.get(item, name, nofollow=nofollow, namespace=namespace))
+		        for name in cls.list(item, nofollow=nofollow, namespace=namespace)]
+
+
+class _XattrSystemCommands(_XattrGetAll):
+	"""Implement things with getfattr/setfattr"""
+
+	@staticmethod
+	def _parse_output(output):
+		for line in output.readlines():
+			if line.startswith(b'#'):
+				continue
+			line = line.rstrip()
+			if not line:
+				continue
+			# The lines will have the format:
+			#	user.hex=0x12345
+			#	user.base64=0sAQAAAgAgAAAAAAAAAAAAAAAAAAA=
+			#	user.string="value0"
+			# But since we don't do interpretation on the value (we just
+			# save & restore it), don't bother with decoding here.
+			yield line.split(b'=', 1)
+
+	@staticmethod
+	def _call(*args, **kwargs):
+		proc = subprocess.Popen(*args, **kwargs)
+		if proc.stdin:
+			proc.stdin.close()
+		proc.wait()
+		return proc
+
+	@classmethod
+	def get(cls, item, name, nofollow=False, namespace=None):
+		if namespace:
+			name = '%s.%s' % (namespace, name)
+		cmd = ['getfattr', '--absolute-names', '-n', name, item]
+		if nofollow:
+			cmd += ['-h']
+		proc = cls._call(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+
+		value = None
+		for _, value in cls._parse_output(proc.stdout):
+			break
+
+		proc.stdout.close()
+		return value
+
+	@classmethod
+	def set(cls, item, name, value, _flags=0, namespace=None):
+		if namespace:
+			name = '%s.%s' % (namespace, name)
+		cmd = ['setfattr', '-n', name, '-v', value, item]
+		cls._call(cmd)
+
+	@classmethod
+	def remove(cls, item, name, nofollow=False, namespace=None):
+		if namespace:
+			name = '%s.%s' % (namespace, name)
+		cmd = ['setfattr', '-x', name, item]
+		if nofollow:
+			cmd += ['-h']
+		cls._call(cmd)
+
+	@classmethod
+	def list(cls, item, nofollow=False, namespace=None, _names_only=True):
+		cmd = ['getfattr', '-d', '--absolute-names', item]
+		if nofollow:
+			cmd += ['-h']
+		cmd += ['-m', ('^%s[.]' % namespace) if namespace else '-']
+		proc = cls._call(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+
+		ret = []
+		if namespace:
+			namespace = '%s.' % namespace
+		for name, value in cls._parse_output(proc.stdout):
+			if namespace:
+				if name.startswith(namespace):
+					name = name[len(namespace):]
+				else:
+					continue
+			if _names_only:
+				ret.append(name)
+			else:
+				ret.append((name, value))
+
+		proc.stdout.close()
+		return ret
+
+	@classmethod
+	def get_all(cls, item, nofollow=False, namespace=None):
+		return cls.list(item, nofollow=nofollow, namespace=namespace,
+		                _names_only=False)
+
+
+class _XattrStub(_XattrGetAll):
+	"""Fake object since system doesn't support xattrs"""
+
+	# pylint: disable=unused-argument
+
+	@staticmethod
+	def _raise():
+		e = OSError('stub')
+		e.errno = OperationNotSupported.errno
+		raise e
+
+	@classmethod
+	def get(cls, item, name, nofollow=False, namespace=None):
+		cls._raise()
+
+	@classmethod
+	def set(cls, item, name, value, flags=0, namespace=None):
+		cls._raise()
+
+	@classmethod
+	def remove(cls, item, name, nofollow=False, namespace=None):
+		cls._raise()
+
+	@classmethod
+	def list(cls, item, nofollow=False, namespace=None):
+		cls._raise()
+
+
+if hasattr(os, 'getxattr'):
+	# Easy as pie -- active python supports it.
+	class xattr(_XattrGetAll):
+		"""Python >=3.3 and GNU/Linux"""
+
+		# pylint: disable=unused-argument
+
+		@staticmethod
+		def get(item, name, nofollow=False, namespace=None):
+			return os.getxattr(item, name, follow_symlinks=not nofollow)
+
+		@staticmethod
+		def set(item, name, value, flags=0, namespace=None):
+			return os.setxattr(item, name, value, flags=flags)
+
+		@staticmethod
+		def remove(item, name, nofollow=False, namespace=None):
+			return os.removexattr(item, name, follow_symlinks=not nofollow)
+
+		@staticmethod
+		def list(item, nofollow=False, namespace=None):
+			return os.listxattr(item, follow_symlinks=not nofollow)
+
+else:
+	try:
+		# Maybe we have the xattr module.
+		import xattr
+
+	except ImportError:
+		try:
+			# Maybe we have the attr package.
+			with open(os.devnull, 'wb') as f:
+				subprocess.call(['getfattr', '--version'], stdout=f)
+				subprocess.call(['setfattr', '--version'], stdout=f)
+			xattr = _XattrSystemCommands
+
+		except OSError:
+			# Stub it out completely.
+			xattr = _XattrStub
+
+
+# Add a knob so code can take evasive action as needed.
+XATTRS_WORKS = xattr != _XattrStub
+
+
+@contextlib.contextmanager
+def preserve_xattrs(path, nofollow=False, namespace=None):
+	"""Context manager to save/restore extended attributes on |path|
+
+	If you want to rewrite a file (possibly replacing it with a new one), but
+	want to preserve the extended attributes, this will do the trick.
+
+	# First read all the extended attributes.
+	with save_xattrs('/some/file'):
+		... rewrite the file ...
+	# Now the extended attributes are restored as needed.
+	"""
+	kwargs = {'nofollow': nofollow,}
+	if namespace:
+		# Compiled xattr python module does not like it when namespace=None.
+		kwargs['namespace'] = namespace
+
+	old_attrs = dict(xattr.get_all(path, **kwargs))
+	try:
+		yield
+	finally:
+		new_attrs = dict(xattr.get_all(path, **kwargs))
+		for name, value in new_attrs.items():
+			if name not in old_attrs:
+				# Clear out new ones.
+				xattr.remove(path, name, **kwargs)
+			elif new_attrs[name] != old_attrs[name]:
+				# Update changed ones.
+				xattr.set(path, name, value, **kwargs)
+
+		for name, value in old_attrs.items():
+			if name not in new_attrs:
+				# Re-add missing ones.
+				xattr.set(path, name, value, **kwargs)
diff --git a/pym/portage/util/movefile.py b/pym/portage/util/movefile.py
index 10005699a..4be1c3b31 100644
--- a/pym/portage/util/movefile.py
+++ b/pym/portage/util/movefile.py
@@ -11,7 +11,6 @@ import os as _os
 import shutil as _shutil
 import stat
 import sys
-import subprocess
 import textwrap
 
 import portage
@@ -23,6 +22,7 @@ from portage.exception import OperationNotSupported
 from portage.localization import _
 from portage.process import spawn
 from portage.util import writemsg
+from portage.util._xattr import xattr
 
 def _apply_stat(src_stat, dest):
 	_os.chown(dest, src_stat.st_uid, src_stat.st_gid)
@@ -68,86 +68,32 @@ class _xattr_excluder(object):
 
 		return False
 
-if hasattr(_os, "getxattr"):
-	# Python >=3.3 and GNU/Linux
-	def _copyxattr(src, dest, exclude=None):
-
-		try:
-			attrs = _os.listxattr(src)
-		except OSError as e:
-			if e.errno != OperationNotSupported.errno:
-				raise
-			attrs = ()
-		if attrs:
-			if exclude is not None and isinstance(attrs[0], bytes):
-				exclude = exclude.encode(_encodings['fs'])
-			exclude = _get_xattr_excluder(exclude)
-
-		for attr in attrs:
-			if exclude(attr):
-				continue
-			try:
-				_os.setxattr(dest, attr, _os.getxattr(src, attr))
-				raise_exception = False
-			except OSError:
-				raise_exception = True
-			if raise_exception:
-				raise OperationNotSupported(_("Filesystem containing file '%s' "
-					"does not support extended attribute '%s'") %
-					(_unicode_decode(dest), _unicode_decode(attr)))
-else:
+def _copyxattr(src, dest, exclude=None):
+	"""Copy the extended attributes from |src| to |dest|"""
 	try:
-		import xattr
-	except ImportError:
-		xattr = None
-	if xattr is not None:
-		def _copyxattr(src, dest, exclude=None):
-
-			try:
-				attrs = xattr.list(src)
-			except IOError as e:
-				if e.errno != OperationNotSupported.errno:
-					raise
-				attrs = ()
+		attrs = xattr.list(src)
+	except (OSError, IOError) as e:
+		if e.errno != OperationNotSupported.errno:
+			raise
+		attrs = ()
 
-			if attrs:
-				if exclude is not None and isinstance(attrs[0], bytes):
-					exclude = exclude.encode(_encodings['fs'])
-				exclude = _get_xattr_excluder(exclude)
+	if attrs:
+		if exclude is not None and isinstance(attrs[0], bytes):
+			exclude = exclude.encode(_encodings['fs'])
+		exclude = _get_xattr_excluder(exclude)
 
-			for attr in attrs:
-				if exclude(attr):
-					continue
-				try:
-					xattr.set(dest, attr, xattr.get(src, attr))
-					raise_exception = False
-				except IOError:
-					raise_exception = True
-				if raise_exception:
-					raise OperationNotSupported(_("Filesystem containing file '%s' "
-						"does not support extended attribute '%s'") %
-						(_unicode_decode(dest), _unicode_decode(attr)))
-	else:
+	for attr in attrs:
+		if exclude(attr):
+			continue
 		try:
-			with open(_os.devnull, 'wb') as f:
-				subprocess.call(["getfattr", "--version"], stdout=f)
-				subprocess.call(["setfattr", "--version"], stdout=f)
-		except OSError:
-			def _copyxattr(src, dest, exclude=None):
-				# TODO: implement exclude
-				getfattr_process = subprocess.Popen(["getfattr", "-d", "--absolute-names", src], stdout=subprocess.PIPE)
-				getfattr_process.wait()
-				extended_attributes = getfattr_process.stdout.readlines()
-				getfattr_process.stdout.close()
-				if extended_attributes:
-					extended_attributes[0] = b"# file: " + _unicode_encode(dest) + b"\n"
-					setfattr_process = subprocess.Popen(["setfattr", "--restore=-"], stdin=subprocess.PIPE, stderr=subprocess.PIPE)
-					setfattr_process.communicate(input=b"".join(extended_attributes))
-					if setfattr_process.returncode != 0:
-						raise OperationNotSupported("Filesystem containing file '%s' does not support extended attributes" % dest)
-		else:
-			def _copyxattr(src, dest, exclude=None):
-				pass
+			xattr.set(dest, attr, xattr.get(src, attr))
+			raise_exception = False
+		except (OSError, IOError):
+			raise_exception = True
+		if raise_exception:
+			raise OperationNotSupported(_("Filesystem containing file '%s' "
+				"does not support extended attribute '%s'") %
+				(_unicode_decode(dest), _unicode_decode(attr)))
 
 def movefile(src, dest, newmtime=None, sstat=None, mysettings=None,
 		hardlink_candidates=None, encoding=_encodings['fs']):
diff --git a/pym/portage/util/xattr.py b/pym/portage/util/xattr.py
deleted file mode 100644
index b8c46208e..000000000
--- a/pym/portage/util/xattr.py
+++ /dev/null
@@ -1,20 +0,0 @@
-# Copyright 2015 Gentoo Foundation
-# Distributed under the terms of the GNU General Public License v2
-
-from __future__ import absolute_import
-
-import os as _os
-
-if hasattr(_os, "getxattr"):
-	getxattr = _os.getxattr
-	listxattr = _os.listxattr
-	setxattr = _os.setxattr
-else:
-	try:
-		import xattr as _xattr
-	except ImportError:
-		pass
-	else:
-		getxattr = _xattr.get
-		listxattr = _xattr.list
-		setxattr = _xattr.set