19 files changed, 1440 insertions, 1257 deletions

diff --git a/doc/Changelog b/doc/Changelog
index 74333fb..197cb17 100644
--- a/doc/Changelog
+++ b/doc/Changelog
@@ -1,4 +1,6 @@
-0.5.3:
+0.6.0:
+- general support for different backend systems
+- removed asterisks as "installed" sign - using an image now
 - added ebuild window
 - added usetips
 - allowed copying out of the console
diff --git a/etc/portato.cfg b/etc/portato.cfg
index 12a3a92..e177714 100644
--- a/etc/portato.cfg
+++ b/etc/portato.cfg
@@ -18,15 +18,20 @@
 #
 [Main]
 
+; controls the backend system to use
+; allowed values:
+;		- portage
+system = portage
+
 ; controls debug output - boolean value
 debug = True
 
 ; the command used for syncing portage - string value
-synccommand = emerge --sync
+synccommand = eix-sync
 
 ; control the same-named "emerge --update" options - boolean values
-newuse = False
-deep = False
+newuse = true
+deep = true
 
 ; control the name of the particular file if package.* is a directory - string values
 ; allowed placeholders: 
diff --git a/portato.py b/portato.py
index 0d357ea..4db4b0e 100755
--- a/portato.py
+++ b/portato.py
@@ -16,11 +16,10 @@ from portato.constants import VERSION, FRONTENDS, STD_FRONTEND
 import sys
 
 if __name__ == "__main__":
-#	import pychecker.checker
 	uimod = STD_FRONTEND
 
-	if len(sys.argv) > 1:
-		if sys.argv[1] in ("--help","--version","-h","-v"):
+	for arg in sys.argv[1:]:
+		if arg in ("--help","--version","-h","-v"):
 			print """Portato %s
 Copyright (C) 2006-2007 René 'Necoro' Neumann
 This is free software.  You may redistribute copies of it under the terms of
@@ -29,8 +28,16 @@ There is NO WARRANTY, to the extent permitted by law.
 
 Written by René 'Necoro' Neumann <necoro@necoro.net>""" % VERSION
 			sys.exit(0)
-		else:
-			uimod = sys.argv[1]
+		
+		if arg == "--check": # run pychecker
+			import os
+			os.environ['PYCHECKER'] = "--limit 50"
+			import pychecker.checker
+			continue
+		
+		uimod = arg
+		break
+
 	if uimod in FRONTENDS:
 		try:
 			exec ("from portato.gui.%s import run" % uimod)
diff --git a/portato/backend/__init__.py b/portato/backend/__init__.py
index a72923b..83ee1d6 100644
--- a/portato/backend/__init__.py
+++ b/portato/backend/__init__.py
@@ -10,67 +10,32 @@
 #
 # Written by René 'Necoro' Neumann <necoro@necoro.net>
 
-import os
-from threading import Lock
+from system_interface import SystemInterface
 
-# import portage
-import portage
+SYSTEM = "portage"
+_sys = None
 
-class PortageSettings:
-	"""Encapsulation of the portage settings.
-	
-	@ivar settings: portage settings
-	@ivar settingslock: a simple Lock
-	@ivar trees: a dictionary of the trees
-	@ivar porttree: shortcut to C{trees[root]["porttree"]}
-	@ivar vartree: shortcut to C{trees[root]["vartree"]}
-	@ivar virtuals: shortcut to C{trees[root]["virtuals"]}"""
+class SystemWrapper (object, SystemInterface):
+	def __getattribute__ (self, name):
+		global _sys
+		return eval ("_sys.%s" % name)
 
-	def __init__ (self):
-		"""Initializes the instance. Calls L{load()}."""
-		self.settingslock = Lock()
-		self.load()
-		
-	def load(self):
-		"""(Re)loads the portage settings and sets the variables."""
+def set_system (new_sys):
+	global SYSTEM
+	SYSTEM = new_sys
+	load_system()
 
-		kwargs = {}
-		for k, envvar in (("config_root", "PORTAGE_CONFIGROOT"), ("target_root", "ROOT")):
-			kwargs[k] = os.environ.get(envvar, None)
-		self.trees = portage.create_trees(trees=None, **kwargs)
+def load_system ():
+	global _sys
 
-		self.settings = self.trees["/"]["vartree"].settings
+	if SYSTEM == "portage":
+		from portato.backend.portage import PortageSystem
+		_sys = PortageSystem ()
 
-		for myroot in self.trees:
-			if myroot != "/":
-				self.settings = self.trees[myroot]["vartree"].settings
-				break
+system = SystemWrapper()
 
-		self.settings.unlock()
-
-		root = self.settings["ROOT"]
-
-		self.porttree = self.trees[root]["porttree"]
-		self.vartree  = self.trees[root]["vartree"]
-		self.virtuals = self.trees[root]["virtuals"]
-		
-		portage.settings = None # we use our own one ...
-
-# portage tree vars
-portage_settings = PortageSettings()
-
-# for the moment ;)
-settingslock = portage_settings.settingslock
-settings = portage_settings.settings
-trees = portage_settings.trees
-porttree = portage_settings.porttree
-vartree = portage_settings.vartree
-virtuals = portage_settings.virtuals
+from exceptions import *
+from package import Package
 
-# this is set to "var/lib/portage/world" by default - so we add the leading /
-portage.WORLD_FILE = portage_settings.settings["ROOT"]+portage.WORLD_FILE
+load_system()
 
-# import our packages
-from exceptions import *
-from package import *
-from portage_helper import *
diff --git a/portato/backend/flags.py b/portato/backend/flags.py
index a7ba125..a7241ca 100644
--- a/portato/backend/flags.py
+++ b/portato/backend/flags.py
@@ -15,12 +15,9 @@ import os.path
 from subprocess import Popen, PIPE # needed for grep
 
 from portato.helper import *
-from portage_helper import split_package_name
+from portato.backend import system
 import package
 
-import portage
-from portage_util import unique_array
-
 CONFIG = {
 		"usefile" : "portato",
 		"maskfile" : "portato",
@@ -30,6 +27,59 @@ CONFIG = {
 		"testingPerVersion" : True
 		}
 
+class Constants:
+
+	def __init__ (self):
+		self.clear()
+	
+	def clear (self):
+		self._use_path = None
+		self._mask_path = None
+		self._unmask_path = None
+		self._testing_path = None
+		self._use_path_is_dir = None
+		self._mask_path_is_dir = None
+		self._unmask_path_is_dir = None
+		self._testing_path_is_dir = None
+
+	def __get (self, name, path):
+		if self.__dict__[name] is None:
+			self.__dict__[name] = os.path.join(system.get_config_path(), path)
+
+		return self.__dict__[name]
+
+	def __is_dir(self, path):
+		name = "_" + path + "_is_dir"
+		if self.__dict__[name] is None:
+			self.__dict__[name] = os.path.isdir(self.__class__.__dict__[path](self))
+		return self.__dict__[name]
+	
+	def use_path (self):
+		return self.__get("_use_path", "package.use")
+
+	def use_path_is_dir (self):
+		return self.__is_dir("use_path")
+
+	def mask_path (self):
+		return self.__get("_mask_path", "package.mask")
+
+	def mask_path_is_dir (self):
+		return self.__is_dir("mask_path")
+
+	def unmask_path (self):
+		return self.__get("_unmask_path", "package.unmask")
+
+	def unmask_path_is_dir (self):
+		return self.__is_dir("unmask_path")
+
+	def testing_path (self):
+		return self.__get("_testing_path", "package.keywords")
+
+	def testing_path_is_dir (self):
+		return self.__is_dir("testing_path")
+
+CONST = Constants()
+
 ### GENERAL PART ###
 
 def grep (pkg, path):
@@ -43,7 +93,7 @@ def grep (pkg, path):
 	@rtype: string"""
 
 	if not isinstance(pkg, package.Package):
-		pkg = package.Package(pkg) # assume it is a cpv or a gentoolkit.Package
+		pkg = system.new_package(pkg) # assume it is a cpv or a gentoolkit.Package
 
 	command = "egrep -x -n -r -H '^[<>!=~]{0,2}%s(-[0-9].*)?[[:space:]]?.*$' %s" # %s is replaced in the next line ;)
 	return Popen((command % (pkg.get_cp(), path)), shell = True, stdout = PIPE).communicate()[0].splitlines()
@@ -105,7 +155,7 @@ def generate_path (cpv, exp):
 	@returns: rendered path
 	@rtype string"""
 
-	cat, pkg, ver, rev = split_package_name(cpv)
+	cat, pkg, ver, rev = system.split_cpv(cpv)
 	
 	if exp.find("$(") != -1:
 		exp = exp.replace("$(cat)",cat).\
@@ -115,8 +165,6 @@ def generate_path (cpv, exp):
 	return exp
 
 ### USE FLAG PART ###
-USE_PATH = os.path.join(portage.USER_CONFIG_PATH,"package.use")
-USE_PATH_IS_DIR = os.path.isdir(USE_PATH)
 useFlags = {} # useFlags in the file
 newUseFlags = {} # useFlags as we want them to be: format: cpv -> [(file, line, useflag, (true if removed from list / false if added))]
 
@@ -150,7 +198,7 @@ def set_use_flag (pkg, flag):
 	global useFlags, newUseFlags
 
 	if not isinstance(pkg, package.Package):
-		pkg = package.Package(pkg) # assume cpv or gentoolkit.Package
+		pkg = system.new_package(pkg) # assume cpv or gentoolkit.Package
 
 	cpv = pkg.get_cpv()
 	invFlag = invert_use_flag(flag)
@@ -158,7 +206,7 @@ def set_use_flag (pkg, flag):
 	# if not saved in useFlags, get it by calling get_data() which calls grep()
 	data = None
 	if not cpv in useFlags:
-		data = get_data(pkg, USE_PATH)
+		data = get_data(pkg, CONST.use_path())
 		useFlags[cpv] = data
 	else:
 		data = useFlags[cpv]
@@ -196,9 +244,9 @@ def set_use_flag (pkg, flag):
 	
 	# create a new line
 	if not added:
-		path = USE_PATH
-		if USE_PATH_IS_DIR:
-			path = os.path.join(USE_PATH, generate_path(cpv, CONFIG["usefile"]))
+		path = CONST.use_path()
+		if CONST.use_path_is_dir():
+			path = os.path.join(CONST.use_path(), generate_path(cpv, CONFIG["usefile"]))
 		try:
 			newUseFlags[cpv].remove((path, -1, invFlag, False))
 		except ValueError: # not in UseFlags
@@ -313,7 +361,7 @@ def write_use_flags ():
 			if CONFIG["usePerVersion"]: # add on a per-version-base
 				msg += "=%s %s\n" % (cpv, ' '.join(flagsToAdd))
 			else: # add on a per-package-base
-				list = split_package_name(cpv)
+				list = system.split_cpv(cpv)
 				msg += "%s/%s %s\n" % (list[0], list[1], ' '.join(flagsToAdd))
 			if not file in file_cache:
 				f = open(file, "a")
@@ -332,11 +380,6 @@ def write_use_flags ():
 	newUseFlags = {}
 
 ### MASKING PART ###
-MASK_PATH = os.path.join(portage.USER_CONFIG_PATH,"package.mask")
-UNMASK_PATH = os.path.join(portage.USER_CONFIG_PATH,"package.unmask")
-MASK_PATH_IS_DIR = os.path.isdir(MASK_PATH)
-UNMASK_PATH_IS_DIR = os.path.isdir(UNMASK_PATH)
-
 new_masked = {}
 new_unmasked = {}
 
@@ -351,7 +394,7 @@ def set_masked (pkg, masked = True):
 	global new_masked, newunmasked
 	
 	if not isinstance(pkg, package.Package):
-		pkg = package.Package(pkg)
+		pkg = system.new_package(pkg)
 
 	cpv = pkg.get_cpv()
 
@@ -363,13 +406,13 @@ def set_masked (pkg, masked = True):
 	if masked:
 		link_neq = new_masked
 		link_eq = new_unmasked
-		path = UNMASK_PATH
+		path = CONST.unmask_path()
 	else:
 		link_neq = new_unmasked
 		link_eq = new_masked
-		path = MASK_PATH
+		path = CONST.mask_path()
 
-	copy = link_eq[cpv]
+	copy = link_eq[cpv][:]
 	for file, line in copy:
 		if line == "-1":
 			link_eq[cpv].remove((file, line))
@@ -393,11 +436,11 @@ def set_masked (pkg, masked = True):
 	if done: return
 
 	if masked:
-		is_dir = MASK_PATH_IS_DIR
-		path = MASK_PATH
+		is_dir = CONST.mask_path_is_dir()
+		path = CONST.mask_path()
 	else:
-		is_dir = UNMASK_PATH_IS_DIR
-		path = UNMASK_PATH
+		is_dir = CONST.unmask_path_is_dir()
+		path = CONST.unmask_path()
 
 	if is_dir:
 		file = os.path.join(path, generate_path(cpv, CONFIG["usefile"]))
@@ -426,9 +469,9 @@ def new_masking_status (cpv):
 	if isinstance(cpv, package.Package):
 		cpv = cpv.get_cpv()
 
-	if cpv in new_masked and new_masked[cpv]:
+	if cpv in new_masked and new_masked[cpv] != []:
 		return "masked"
-	elif cpv in new_unmasked and new_unmasked[cpv]:
+	elif cpv in new_unmasked and new_unmasked[cpv] != []:
 		return "unmasked"
 	else: return None
 
@@ -444,7 +487,7 @@ def write_masked ():
 			if CONFIG["maskPerVersion"]:
 				msg += "=%s\n" % cpv
 			else:
-				list = split_package_name(cpv)
+				list = system.split_cpv(cpv)
 				msg += "%s/%s\n" % (list[0],list[1])
 			if not file in file_cache:
 				f = open(file, "a")
@@ -497,8 +540,6 @@ def write_masked ():
 	new_unmasked = {}
 
 ### TESTING PART ###
-TESTING_PATH = os.path.join(portage.USER_CONFIG_PATH, "package.keywords")
-TESTING_PATH_IS_DIR = os.path.isdir(TESTING_PATH)
 newTesting = {}
 arch = ""
 
@@ -531,7 +572,7 @@ def set_testing (pkg, enable):
 
 	global arch, newTesting
 	if not isinstance(pkg, package.Package):
-		pkg = package.Package(pkg)
+		pkg = system.new_package(pkg)
 
 	arch = pkg.get_settings("ARCH")
 	cpv = pkg.get_cpv()
@@ -546,16 +587,16 @@ def set_testing (pkg, enable):
 		return
 
 	if not enable:
-		test = get_data(pkg, TESTING_PATH)
+		test = get_data(pkg, CONST.testing_path())
 		debug("data (test): "+str(test))
 		for file, line, crit, flags in test:
 			if pkg.matches(crit) and flags[0] == "~"+arch:
 				newTesting[cpv].append((file, line))
 	else:
-		if TESTING_PATH_IS_DIR:
-			file = os.path.join(TESTING_PATH, CONFIG["testingfile"])
+		if CONST.testing_path_is_dir():
+			file = os.path.join(CONST.testing_path(), CONFIG["testingfile"])
 		else:
-			file = TESTING_PATH
+			file = CONST.testing_path()
 		newTesting[cpv].append((file, "-1"))
 
 	newTesting[cpv] = unique_array(newTesting[cpv])
@@ -574,7 +615,7 @@ def write_testing ():
 				if CONFIG["testingPerVersion"]:
 					msg += "=%s ~%s\n" % (cpv, arch)
 				else:
-					list = split_package_name(cpv)
+					list = system.split_cpv(cpv)
 					msg += "%s/%s ~%s\n" % (list[0],list[1],arch)
 				if not file in file_cache:
 					f = open(file, "a")
diff --git a/portato/backend/package.py b/portato/backend/package.py
deleted file mode 100644
index 6ba47fe..0000000
--- a/portato/backend/package.py
+++ /dev/null
@@ -1,447 +0,0 @@
-# -*- coding: utf-8 -*-
-#
-# File: portato/backend/package.py
-# This file is part of the Portato-Project, a graphical portage-frontend.
-#
-# Copyright (C) 2006-2007 René 'Necoro' Neumann
-# This is free software.  You may redistribute copies of it under the terms of
-# the GNU General Public License version 2.
-# There is NO WARRANTY, to the extent permitted by law.
-#
-# Written by René 'Necoro' Neumann <necoro@necoro.net>
-
-from portato.backend import portage_settings
-from portato.helper import *
-from portage_helper import *
-from exceptions import *
-import flags
-
-import portage, portage_dep
-from portage_util import unique_array
-
-import types
-import os.path
-
-class Package:
-	"""This is a class abstracting a normal package which can be installed."""
-
-	def __init__ (self, cpv):
-		"""Constructor.
-
-		@param cpv: The cpv which describes the package to create.
-		@type cpv: string (cat/pkg-ver)"""
-
-		self._cpv = cpv
-		self._scpv = portage.catpkgsplit(self._cpv)
-		
-		if not self._scpv:
-			raise ValueError("invalid cpv: %s" % cpv)
-
-		self._settings = portage_settings.settings
-		self._settingslock = portage_settings.settingslock
-
-		self._trees = portage_settings.trees
-
-		self.forced_flags = set()
-		self.forced_flags.update(self._settings.usemask)
-		self.forced_flags.update(self._settings.useforce)
-		
-		try:
-			self._status = portage.getmaskingstatus(self.get_cpv(), settings = self._settings)
-		except KeyError: # package is not located in the system
-			self._status = None
-	
-	def is_installed(self):
-		"""Returns true if this package is installed (merged)
-		@rtype: boolean"""
-		
-		return portage_settings.vartree.dbapi.cpv_exists(self._cpv)
-
-	def is_overlay(self):
-		"""Returns true if the package is in an overlay.
-		@rtype: boolean"""
-		
-		dir,ovl = portage_settings.porttree.dbapi.findname2(self._cpv)
-		return ovl != self._settings["PORTDIR"]
-
-	def is_in_system (self):
-		"""Returns False if the package could not be found in the portage system.
-
-		@return: True if in portage system; else False
-		@rtype: boolean"""
-
-		return (self._status != None)
-
-	def is_missing_keyword(self):
-		"""Returns True if the package is missing the needed keyword.
-		
-		@return: True if keyword is missing; else False
-		@rtype: boolean"""
-		
-		if self._status and "missing keyword" in self._status:
-			return True
-		return False
-
-	def is_testing(self, use_keywords = False):
-		"""Checks whether a package is marked as testing.
-		
-		@param use_keywords: Controls whether possible keywords are taken into account or not.
-		@type use_keywords: boolean
-		@returns: True if the package is marked as testing; else False.
-		@rtype: boolean"""
-
-		testArch = "~" + self.get_settings("ARCH")
-		if not use_keywords: # keywords are NOT taken into account
-			if testArch in self.get_env_var("KEYWORDS").split():
-				return True
-			return False
-		
-		else: # keywords are taken into account
-			status = flags.new_testing_status(self.get_cpv())
-			if status is None: # we haven't changed it in any way
-				if self._status and testArch+" keyword" in self._status:
-					return True
-				return False
-			else:
-				return status
-	
-	def set_testing(self, enable = True):
-		"""Sets the actual testing status of the package.
-		
-		@param enable: if True it is masked as stable; if False it is marked as testing
-		@type enable: boolean"""
-		
-		flags.set_testing(self, enable)
-
-	def remove_new_testing(self):
-		"""Removes possible changed testing status."""
-		
-		flags.remove_new_testing(self.get_cpv())
-
-	def is_masked (self):
-		"""Returns True if either masked by package.mask or by profile.
-		
-		@returns: True if masked / False otherwise
-		@rtype: boolean"""
-		
-		status = flags.new_masking_status(self.get_cpv())
-		if status != None: # we have locally changed it
-			if status == "masked": return True
-			elif status == "unmasked": return False
-			else:
-				debug("BUG in flags.new_masking_status. It returns",status)
-		else: # we have not touched the status
-			if self._status and ("profile" in self._status or "package.mask" in self._status):
-				return True
-			return False
-
-	def set_masked (self, masking = False):
-		"""Sets the masking status of the package.
-	
-		@param masking: if True: mask it; if False: unmask it
-		@type masking: boolean"""
-		
-		flags.set_masked(self, masked = masking)
-
-	def remove_new_masked (self):
-		"""Removes possible changed masking status."""
-		
-		flags.remove_new_masked(self.get_cpv())
-
-	def get_all_use_flags (self, installed = False):
-		"""Returns a list of _all_ useflags for this package, i.e. all useflags you can set for this package.
-		
-		@param installed: do not take the ones stated in the ebuild, but the ones it has been installed with
-		@type installed: boolean
-
-		@returns: list of use-flags
-		@rtype: string[]"""
-
-		if installed or not self.is_in_system():
-			tree = portage_settings.vartree
-		else:
-			tree = portage_settings.porttree
-		
-		return list(set(self.get_env_var("IUSE", tree = tree).split()).difference(self.forced_flags))
-
-	def get_installed_use_flags (self):
-		"""Returns a list of the useflags enabled at installation time. If package is not installed, it returns an empty list.
-		
-		@returns: list of useflags enabled at installation time or an empty list
-		@rtype: string[]"""
-		
-		if self.is_installed():
-			uses = set(self.get_use_flags().split()) # all set at installation time
-			iuses = set(self.get_all_use_flags(installed=True)) # all you can set for the package
-			
-			return list(uses.intersection(iuses))
-		else:
-			return []
-	
-	def get_new_use_flags (self):
-		"""Returns a list of the new useflags, i.e. these flags which are not written to the portage-system yet.
-
-		@returns: list of flags or []
-		@rtype: string[]"""
-
-		return flags.get_new_use_flags(self)
-
-	def get_actual_use_flags (self):
-		"""This returns the result of installed_use_flags + new_use_flags. If the package is not installed, it returns only the new flags.
-
-		@return: list of flags
-		@rtype: string[]"""
-
-		if self.is_installed():
-			i_flags = self.get_installed_use_flags()
-			for f in self.get_new_use_flags():
-				
-				if flags.invert_use_flag(f) in i_flags:
-					i_flags.remove(flags.invert_use_flag(f))
-				
-				elif f not in i_flags:
-					i_flags.append(f)
-			return i_flags
-		else:
-			return self.get_new_use_flags()
-
-	def set_use_flag (self, flag):
-		"""Set a use-flag.
-
-		@param flag: the flag to set
-		@type flag: string"""
-		
-		flags.set_use_flag(self, flag)
-
-	def remove_new_use_flags (self):
-		"""Remove all the new use-flags."""
-		
-		flags.remove_new_use_flags(self)
-
-	def is_use_flag_enabled (self, flag):
-		"""Looks whether a given useflag is enabled for the package, taking all options
-		(ie. even the new flags) into account.
-
-		@param flag: the flag to check
-		@type flag: string
-		@returns: True or False
-		@rtype: bool"""
-		
-		if self.is_installed() and flag in self.get_actual_use_flags(): # flags set during install
-			return True
-		
-		elif (not self.is_installed()) and flag in self.get_settings("USE").split() \
-				and not flags.invert_use_flag(flag) in self.get_new_use_flags(): # flags that would be set
-			return True
-		
-		elif flag in self.get_new_use_flags():
-			return True
-		
-		else:
-			return False
-
-	def get_matched_dep_packages (self, depvar):
-		"""This function looks for all dependencies which are resolved. In normal case it makes only sense for installed packages, but should work for uninstalled ones too.
-
-		@returns: unique list of dependencies resolved (with elements like "<=net-im/foobar-1.2.3")
-		@rtype: string[]
-
-		@raises portato.DependencyCalcError: when an error occured during executing portage.dep_check()"""
-		
-		# change the useflags, because we have internally changed some, but not made them visible for portage
-		newUseFlags = self.get_new_use_flags()
-		actual = self.get_settings("USE").split()
-		if newUseFlags:
-			for u in newUseFlags:
-				if u[0] == "-" and flags.invert_use_flag(u) in actual:
-					actual.remove(flags.invert_use_flag(u))
-				elif u not in actual:
-					actual.append(u)
-		
-		depstring = ""
-		for d in depvar:
-			depstring += self.get_env_var(d)+" "
-
-		portage_dep._dep_check_strict = False
-		deps = portage.dep_check(depstring, None, self._settings, myuse = actual, trees = self._trees)
-		portage_dep._dep_check_strict = True
-
-		if not deps: # FIXME: what is the difference to [1, []] ?
-			return [] 
-
-		if deps[0] == 0: # error
-			raise DependencyCalcError, deps[1]
-		
-		deps = deps[1]
-
-		retlist = []
-		
-		for d in deps:
-			if not d[0] == "!":
-				retlist.append(d)
-
-		return retlist
-
-	def get_dep_packages (self, depvar = ["RDEPEND", "PDEPEND", "DEPEND"]):
-		"""Returns a cpv-list of packages on which this package depends and which have not been installed yet. This does not check the dependencies in a recursive manner.
-
-		@returns: list of cpvs on which the package depend
-		@rtype: string[]
-
-		@raises portato.BlockedException: when a package in the dependency-list is blocked by an installed one
-		@raises portato.PackageNotFoundException: when a package in the dependency list could not be found in the system
-		@raises portato.DependencyCalcError: when an error occured during executing portage.dep_check()"""
-
-		dep_pkgs = [] # the package list
-		
-		# change the useflags, because we have internally changed some, but not made them visible for portage
-		newUseFlags = self.get_new_use_flags()
-		actual = self.get_settings("USE").split()
-		if newUseFlags:
-			for u in newUseFlags:
-				if u[0] == "-" and flags.invert_use_flag(u) in actual:
-					actual.remove(flags.invert_use_flag(u))
-				elif u not in actual:
-					actual.append(u)
-
-		depstring = ""
-		for d in depvar:
-			depstring += self.get_env_var(d)+" "
-
-		# let portage do the main stuff ;)
-		# pay attention to any changes here
-		deps = portage.dep_check (depstring, portage_settings.vartree.dbapi, self._settings, myuse = actual, trees = self._trees)
-		
-		if not deps: # FIXME: what is the difference to [1, []] ?
-			return [] 
-
-		if deps[0] == 0: # error
-			raise DependencyCalcError, deps[1]
-		
-		deps = deps[1]
-
-		for dep in deps:
-			if dep[0] == '!': # blocking sth
-				dep = dep[1:]
-				if dep != self.get_cp(): # not cpv, because a version might explicitly block another one
-					blocked = find_installed_packages(dep)
-					if blocked != []:
-						raise BlockedException, (self.get_cpv(), blocked[0].get_cpv())
-				continue # finished with the blocking one -> next
-
-			pkg = find_best_match(dep)
-			if not pkg: # try to find masked ones
-				list = find_packages(dep, masked = True)
-				if not list:
-					raise PackageNotFoundException, dep
-
-				list = sort_package_list(list)
-				done = False
-				for i in range(len(list)-1,0,-1):
-					p = list[i]
-					if not p.is_masked():
-						dep_pkgs.append(p.get_cpv())
-						done = True
-						break
-				if not done:
-					dep_pkgs.append(list[-1].get_cpv())
-			else:
-				dep_pkgs.append(pkg.get_cpv())
-
-		return dep_pkgs
-
-	def get_cpv(self):
-		"""Returns full Category/Package-Version string"""
-		return self._cpv
-
-	def get_cp (self):
-		"""Returns the cp-string.
-		
-		@returns: category/package.
-		@rtype: string"""
-		
-		return self.get_category()+"/"+self.get_name()
-
-	def get_slot_cp (self):
-
-		return ("%s:%s" % (self.get_cp(), self.get_env_var("SLOT")))
-
-	def get_name(self):
-		"""Returns base name of package, no category nor version"""
-		return self._scpv[1]
-
-	def get_version(self):
-		"""Returns version of package, with revision number"""
-		v = self._scpv[2]
-		if self._scpv[3] != "r0":
-			v += "-" + self._scpv[3]
-		return v
-
-	def get_category(self):
-		"""Returns category of package"""
-		return self._scpv[0]
-
-	def get_settings(self, key):
-		"""Returns the value of the given key for this package (useful 
-		for package.* files)."""
-		self._settingslock.acquire()
-		self._settings.setcpv(self._cpv)
-		v = self._settings[key]
-		self._settingslock.release()
-		return v
-
-	def get_ebuild_path(self):
-		"""Returns the complete path to the .ebuild file"""
-		return portage_settings.porttree.dbapi.findname(self._cpv)
-
-	def get_package_path(self):
-		"""Returns the path to where the ChangeLog, Manifest, .ebuild files reside"""
-		p = self.get_ebuild_path()
-		sp = p.split("/")
-		if len(sp):
-			import string
-			return string.join(sp[:-1],"/")
-
-	def get_env_var(self, var, tree = None):
-		"""Returns one of the predefined env vars DEPEND, RDEPEND, SRC_URI,...."""
-		if not tree:
-			mytree = portage_settings.vartree
-			if not self.is_installed():
-				mytree = portage_settings.porttree
-		else:
-			mytree = tree
-		r = mytree.dbapi.aux_get(self._cpv,[var])
-		
-		return r[0]
-
-	def get_use_flags(self):
-		if self.is_installed():
-			return self.get_env_var("USE", tree = portage_settings.vartree)
-		else: return ""
-
-	def compare_version(self,other):
-		"""Compares this package's version to another's CPV; returns -1, 0, 1"""
-		v1 = self._scpv
-		v2 = portage.catpkgsplit(other.get_cpv())
-		# if category is different
-		if v1[0] != v2[0]:
-			return cmp(v1[0],v2[0])
-		# if name is different
-		elif v1[1] != v2[1]:
-			return cmp(v1[1],v2[1])
-		# Compare versions
-		else:
-			return portage.pkgcmp(v1[1:],v2[1:])
-
-	def matches (self, criterion):
-		"""This checks, whether this package matches a specific verisioning criterion - e.g.: "<=net-im/foobar-1.2".
-		
-		@param criterion: the criterion to match against
-		@type criterion: string
-		@returns: True if matches; False if not
-		@rtype: boolean"""
-		
-		if portage.match_from_list(criterion, [self.get_cpv()]) == []:
-			return False
-		else:
-			return True
diff --git a/portato/backend/portage/__init__.py b/portato/backend/portage/__init__.py
new file mode 100644
index 0000000..e21278c
--- /dev/null
+++ b/portato/backend/portage/__init__.py
@@ -0,0 +1,14 @@
+# -*- coding: utf-8 -*-
+#
+# File: portato/backend/portage/__init__.py
+# This file is part of the Portato-Project, a graphical portage-frontend.
+#
+# Copyright (C) 2006-2007 René 'Necoro' Neumann
+# This is free software.  You may redistribute copies of it under the terms of
+# the GNU General Public License version 2.
+# There is NO WARRANTY, to the extent permitted by law.
+#
+# Written by René 'Necoro' Neumann <necoro@necoro.net>
+
+from system import PortageSystem
+from package import PortagePackage
diff --git a/portato/backend/portage/package.py b/portato/backend/portage/package.py
new file mode 100644
index 0000000..74a5107
--- /dev/null
+++ b/portato/backend/portage/package.py
@@ -0,0 +1,234 @@
+# -*- coding: utf-8 -*-
+#
+# File: portato/backend/portage/package.py
+# This file is part of the Portato-Project, a graphical portage-frontend.
+#
+# Copyright (C) 2006-2007 René 'Necoro' Neumann
+# This is free software.  You may redistribute copies of it under the terms of
+# the GNU General Public License version 2.
+# There is NO WARRANTY, to the extent permitted by law.
+#
+# Written by René 'Necoro' Neumann <necoro@necoro.net>
+
+from portato.helper import *
+from portato.backend.exceptions import *
+from portato.backend import flags, Package, system
+
+import portage, portage_dep
+from portage_util import unique_array
+
+import os.path
+
+class PortagePackage (Package):
+	"""This is a class abstracting a normal package which can be installed for the portage-system."""
+
+	def __init__ (self, cpv):
+		"""Constructor.
+
+		@param cpv: The cpv which describes the package to create.
+		@type cpv: string (cat/pkg-ver)"""
+
+		Package.__init__(self, cpv)
+		self._settings = system.settings
+		self._settingslock = system.settings.settingslock
+
+		self._trees = system.settings.trees
+
+		self.forced_flags = set()
+		self.forced_flags.update(self._settings.settings.usemask)
+		self.forced_flags.update(self._settings.settings.useforce)
+		
+		try:
+			self._status = portage.getmaskingstatus(self.get_cpv(), settings = self._settings.settings)
+		except KeyError: # package is not located in the system
+			self._status = None
+	
+	def is_installed(self):
+		return self._settings.vartree.dbapi.cpv_exists(self._cpv)
+
+	def is_overlay(self):
+		dir,ovl = self._settings.porttree.dbapi.findname2(self._cpv)
+		return ovl != self._settings.settings["PORTDIR"]
+
+	def is_in_system (self):
+		return (self._status != None)
+
+	def is_missing_keyword(self):
+		if self._status and "missing keyword" in self._status:
+			return True
+		return False
+
+	def is_testing(self, use_keywords = False):
+		testArch = "~" + self.get_settings("ARCH")
+		if not use_keywords: # keywords are NOT taken into account
+			if testArch in self.get_env_var("KEYWORDS").split():
+				return True
+			return False
+		
+		else: # keywords are taken into account
+			status = flags.new_testing_status(self.get_cpv())
+			if status is None: # we haven't changed it in any way
+				if self._status and testArch+" keyword" in self._status:
+					return True
+				return False
+			else:
+				return status
+	
+	def is_masked (self):
+		status = flags.new_masking_status(self.get_cpv())
+		if status != None: # we have locally changed it
+			if status == "masked": return True
+			elif status == "unmasked": return False
+			else:
+				debug("BUG in flags.new_masking_status. It returns",status)
+		else: # we have not touched the status
+			if self._status and ("profile" in self._status or "package.mask" in self._status):
+				return True
+			return False
+
+	def get_all_use_flags (self, installed = False):
+		if installed or not self.is_in_system():
+			tree = self._settings.vartree
+		else:
+			tree = self._settings.porttree
+		
+		return list(set(self.get_env_var("IUSE", tree = tree).split()).difference(self.forced_flags))
+
+	def get_matched_dep_packages (self, depvar):
+		# change the useflags, because we have internally changed some, but not made them visible for portage
+		newUseFlags = self.get_new_use_flags()
+		actual = self.get_settings("USE").split()
+		if newUseFlags:
+			for u in newUseFlags:
+				if u[0] == "-" and flags.invert_use_flag(u) in actual:
+					actual.remove(flags.invert_use_flag(u))
+				elif u not in actual:
+					actual.append(u)
+		
+		depstring = ""
+		for d in depvar:
+			depstring += self.get_env_var(d)+" "
+
+		portage_dep._dep_check_strict = False
+		deps = portage.dep_check(depstring, None, self._settings.settings, myuse = actual, trees = self._trees)
+		portage_dep._dep_check_strict = True
+
+		if not deps: # FIXME: what is the difference to [1, []] ?
+			return [] 
+
+		if deps[0] == 0: # error
+			raise DependencyCalcError, deps[1]
+		
+		deps = deps[1]
+
+		retlist = []
+		
+		for d in deps:
+			if not d[0] == "!":
+				retlist.append(d)
+
+		return retlist
+
+	def get_dep_packages (self, depvar = ["RDEPEND", "PDEPEND", "DEPEND"]):
+		dep_pkgs = [] # the package list
+		
+		# change the useflags, because we have internally changed some, but not made them visible for portage
+		newUseFlags = self.get_new_use_flags()
+		actual = self.get_settings("USE").split()
+		if newUseFlags:
+			for u in newUseFlags:
+				if u[0] == "-" and flags.invert_use_flag(u) in actual:
+					actual.remove(flags.invert_use_flag(u))
+				elif u not in actual:
+					actual.append(u)
+
+		depstring = ""
+		for d in depvar:
+			depstring += self.get_env_var(d)+" "
+
+		# let portage do the main stuff ;)
+		# pay attention to any changes here
+		deps = portage.dep_check (depstring, self._settings.vartree.dbapi, self._settings.settings, myuse = actual, trees = self._trees)
+		
+		if not deps: # FIXME: what is the difference to [1, []] ?
+			return [] 
+
+		if deps[0] == 0: # error
+			raise DependencyCalcError, deps[1]
+		
+		deps = deps[1]
+
+		for dep in deps:
+			if dep[0] == '!': # blocking sth
+				dep = dep[1:]
+				if dep != self.get_cp(): # not cpv, because a version might explicitly block another one
+					blocked = system.find_installed_packages(dep)
+					if blocked != []:
+						raise BlockedException, (self.get_cpv(), blocked[0].get_cpv())
+				continue # finished with the blocking one -> next
+
+			pkg = system.find_best_match(dep)
+			if not pkg: # try to find masked ones
+				list = system.find_packages(dep, masked = True)
+				if not list:
+					raise PackageNotFoundException, dep
+
+				list = system.sort_package_list(list)
+				done = False
+				for i in range(len(list)-1,0,-1):
+					p = list[i]
+					if not p.is_masked():
+						dep_pkgs.append(p.get_cpv())
+						done = True
+						break
+				if not done:
+					dep_pkgs.append(list[-1].get_cpv())
+			else:
+				dep_pkgs.append(pkg.get_cpv())
+
+		return dep_pkgs
+
+	def get_settings(self, key):
+		self._settingslock.acquire()
+		self._settings.settings.setcpv(self._cpv)
+		v = self._settings.settings[key]
+		self._settingslock.release()
+		return v
+
+	def get_ebuild_path(self):
+		return self._settings.porttree.dbapi.findname(self._cpv)
+
+	def get_env_var(self, var, tree = None):
+		if not tree:
+			mytree = self._settings.vartree
+			if not self.is_installed():
+				mytree = self._settings.porttree
+		else:
+			mytree = tree
+		r = mytree.dbapi.aux_get(self._cpv,[var])
+		
+		return r[0]
+
+	def get_use_flags(self):
+		if self.is_installed():
+			return self.get_env_var("USE", tree = self._settings.vartree)
+		else: return ""
+
+	def compare_version(self,other):
+		v1 = self._scpv
+		v2 = portage.catpkgsplit(other.get_cpv())
+		# if category is different
+		if v1[0] != v2[0]:
+			return cmp(v1[0],v2[0])
+		# if name is different
+		elif v1[1] != v2[1]:
+			return cmp(v1[1],v2[1])
+		# Compare versions
+		else:
+			return portage.pkgcmp(v1[1:],v2[1:])
+
+	def matches (self, criterion):
+		if portage.match_from_list(criterion, [self.get_cpv()]) == []:
+			return False
+		else:
+			return True
diff --git a/portato/backend/portage/settings.py b/portato/backend/portage/settings.py
new file mode 100644
index 0000000..5d3aef0
--- /dev/null
+++ b/portato/backend/portage/settings.py
@@ -0,0 +1,55 @@
+# -*- coding: utf-8 -*-
+#
+# File: portato/backend/portage/settings.py
+# This file is part of the Portato-Project, a graphical portage-frontend.
+#
+# Copyright (C) 2006-2007 René 'Necoro' Neumann
+# This is free software.  You may redistribute copies of it under the terms of
+# the GNU General Public License version 2.
+# There is NO WARRANTY, to the extent permitted by law.
+#
+# Written by René 'Necoro' Neumann <necoro@necoro.net>
+
+import os
+import portage
+from threading import Lock
+
+class PortageSettings:
+	"""Encapsulation of the portage settings.
+	
+	@ivar settings: portage settings
+	@ivar settingslock: a simple Lock
+	@ivar trees: a dictionary of the trees
+	@ivar porttree: shortcut to C{trees[root]["porttree"]}
+	@ivar vartree: shortcut to C{trees[root]["vartree"]}
+	@ivar virtuals: shortcut to C{trees[root]["virtuals"]}"""
+
+	def __init__ (self):
+		"""Initializes the instance. Calls L{load()}."""
+		self.settingslock = Lock()
+		self.load()
+		
+	def load(self):
+		"""(Re)loads the portage settings and sets the variables."""
+
+		kwargs = {}
+		for k, envvar in (("config_root", "PORTAGE_CONFIGROOT"), ("target_root", "ROOT")):
+			kwargs[k] = os.environ.get(envvar, None)
+		self.trees = portage.create_trees(trees=None, **kwargs)
+
+		self.settings = self.trees["/"]["vartree"].settings
+
+		for myroot in self.trees:
+			if myroot != "/":
+				self.settings = self.trees[myroot]["vartree"].settings
+				break
+
+		self.settings.unlock()
+
+		root = self.settings["ROOT"]
+
+		self.porttree = self.trees[root]["porttree"]
+		self.vartree  = self.trees[root]["vartree"]
+		self.virtuals = self.trees[root]["virtuals"]
+		
+		portage.settings = None # we use our own one ...
diff --git a/portato/backend/portage/system.py b/portato/backend/portage/system.py
new file mode 100644
index 0000000..1cfda62
--- /dev/null
+++ b/portato/backend/portage/system.py
@@ -0,0 +1,370 @@
+# -*- coding: utf-8 -*-
+#
+# File: portato/backend/portage/system.py
+# This file is part of the Portato-Project, a graphical portage-frontend.
+#
+# Copyright (C) 2006-2007 René 'Necoro' Neumann
+# This is free software.  You may redistribute copies of it under the terms of
+# the GNU General Public License version 2.
+# There is NO WARRANTY, to the extent permitted by law.
+#
+# Written by René 'Necoro' Neumann <necoro@necoro.net>
+
+import re, os
+import types
+import portage
+
+import package
+from settings import PortageSettings
+from portato.helper import debug, unique_array
+from portato.backend.system_interface import SystemInterface
+
+class PortageSystem (SystemInterface):
+	
+	def __init__ (self):
+
+		self.settings = PortageSettings()
+		portage.WORLD_FILE = self.settings.settings["ROOT"]+portage.WORLD_FILE
+
+	def new_package (self, cpv):
+		return package.PortagePackage(cpv)
+
+	def get_config_path (self):
+		return portage.USER_CONFIG_PATH
+
+	def get_world_file_path (self):
+		return portage.WORLD_FILE
+
+	def get_merge_command (self):
+		return ["/usr/bin/python", "/usr/bin/emerge"]
+
+	def get_sync_command (self):
+		return self.get_merge_command()+["--sync"]
+
+	def get_oneshot_option (self):
+		return ["--oneshot"]
+
+	def get_newuse_option (self):
+		return ["--newuse"]
+
+	def get_deep_option (self):
+		return ["--deep"]
+
+	def get_update_option (self):
+		return ["--update"]
+
+	def get_pretend_option (self):
+		return ["--pretend", "--verbose"]
+
+	def get_unmerge_option (self):
+		return ["--unmerge"]
+
+	def find_lambda (self, name):
+		"""Returns the function needed by all the find_all_*-functions. Returns None if no name is given.
+		
+		@param name: name to build the function of
+		@type name: string
+		@returns: 
+					1. None if no name is given
+					2. a lambda function
+		@rtype: function"""
+		
+		if name != None:
+			return lambda x: re.match(".*"+name+".*",x)
+		else:
+			return lambda x: True
+
+	def geneticize_list (self, list_of_packages):
+		"""Convertes a list of cpv's into L{backend.Package}s.
+		
+		@param list_of_packages: the list of packages
+		@type list_of_packages: list of gentoolkit.Packages
+		@returns: converted list
+		@rtype: PortagePackage[]"""
+		
+		return [package.PortagePackage(x) for x in list_of_packages]
+
+	def find_best (self, list):
+		return package.PortagePackage(portage.best(list))
+
+	def find_best_match (self, search_key, only_installed = False):
+		t = None
+		if not only_installed:
+			t = self.settings.porttree.dep_bestmatch(search_key)
+		else:
+			t = self.settings.vartree.dep_bestmatch(search_key)
+		if t:
+			return package.PortagePackage(t)
+		return None
+
+	def find_packages (self, search_key, masked=False):
+		try:
+			if masked:
+				t = self.settings.porttree.dbapi.xmatch("match-all", search_key)
+				t += self.settings.vartree.dbapi.match(search_key)
+			else:
+				t = self.settings.porttree.dbapi.match(search_key)
+				t += self.settings.vartree.dbapi.match(search_key)
+		# catch the "ambigous package" Exception
+		except ValueError, e:
+			if type(e[0]) == types.ListType:
+				t = []
+				for cp in e[0]:
+					if masked:
+						t += self.settings.porttree.dbapi.xmatch("match-all", cp)
+						t += self.settings.vartree.dbapi.match(cp)
+					else:
+						t += self.settings.porttree.dbapi.match(cp)
+						t += self.settings.vartree.dbapi.match(cp)
+			else:
+				raise ValueError(e)
+		# Make the list of packages unique
+		t = unique_array(t)
+		t.sort()
+		return self.geneticize_list(t)
+
+	def find_installed_packages (self, search_key, masked = False):
+		try:
+			t = self.settings.vartree.dbapi.match(search_key)
+		# catch the "ambigous package" Exception
+		except ValueError, e:
+			if type(e[0]) == types.ListType:
+				t = []
+				for cp in e[0]:
+					t += self.settings.vartree.dbapi.match(cp)
+			else:
+				raise ValueError(e)
+
+		return self.geneticize_list(t)
+
+	def __find_resolved_unresolved (self, list, check):
+		resolved = []
+		unresolved = []
+		for x in list:
+			cpv = x.strip()
+			if len(cpv) and check(cpv):
+				pkg = self.find_best_match(cpv)
+				if pkg:
+					resolved.append(pkg)
+				else:
+					unresolved.append(cpv)
+		return (resolved, self.geneticize_list(unresolved))
+	
+	def find_system_packages (self):
+		pkglist = self.settings.settings.packages
+
+		return self.__find_resolved_unresolved(pkglist, lambda cpv: cpv[0] == "*")
+
+	def find_world_packages (self):
+		f = open(portage.WORLD_FILE)
+		pkglist = f.readlines()
+		f.close()
+
+		return self.__find_resolved_unresolved(pkglist, lambda cpv: cpv[0] != "#")
+
+	def find_all_installed_packages (self, name = None, withVersion=True):
+		if withVersion:
+			t = self.settings.vartree.dbapi.cpv_all()
+			if name:
+				t = filter(self.find_lambda(name),t)
+			return self.geneticize_list(t)
+		
+		else:
+			t = self.settings.vartree.dbapi.cp_all()
+			if name:
+				t = filter(self.find_lambda(name),t)
+			return t
+
+	def find_all_uninstalled_packages (self, name = None):
+		alist = self.find_all_packages(name)
+		return self.geneticize_list([x for x in alist if not x.is_installed()])	
+
+	def find_all_packages (self, name = None, withVersion = True):
+		t = self.settings.porttree.dbapi.cp_all()
+		t += self.settings.vartree.dbapi.cp_all()
+		if name:
+			t = filter(self.find_lambda(name),t)
+		t = unique_array(t)
+		
+		if (withVersion):
+			t2 = []
+			for x in t:
+				t2 += self.settings.porttree.dbapi.cp_list(x)
+				t2 += self.settings.vartree.dbapi.cp_list(x)
+				t2 = unique_array(t2)
+			return self.geneticize_list(t2)
+		else:
+			return t;
+
+	def find_all_world_packages (self, name = None):
+		world = filter(self.find_lambda(name), [x.get_cpv() for x in self.find_world_packages()[0]])
+		world = unique_array(world)
+		return self.geneticize_list(world)
+
+	def find_all_system_packages (self, name = None):
+		sys = filter(self.find_lambda(name), [x.get_cpv() for x in self.find_system_packages()[0]])
+		sys = unique_array(sys)
+		return self.geneticize_list(sys)
+
+	def list_categories (self, name = None):
+		categories = self.settings.settings.categories
+		return filter(self.find_lambda(name), categories)
+
+	def split_cpv (self, cpv):
+		cpv = portage.dep_getcpv(cpv)
+		return portage.catpkgsplit(cpv)
+
+	def sort_package_list(self, pkglist):
+		pkglist.sort(package.PortagePackage.compare_version)
+		return pkglist
+
+	def reload_settings (self):
+		self.settings.load()
+
+	def update_world (self, newuse = False, deep = False):
+		# read world file
+		world = open(portage.WORLD_FILE)
+		packages = []
+		for line in world:
+			line = line.strip()
+			if len(line) == 0: continue # empty line
+			if line[0] == "#": continue # comment
+			packages.append(line)
+		world.close()
+
+		# append system packages
+		packages.extend(unique_array([p.get_cp() for p in self.find_all_system_packages()]))
+
+		def get_new_packages (packages):
+			new_packages = []
+			for p in packages:
+				inst = self.find_installed_packages(p)
+				if len(inst) > 1:
+					myslots = set()
+					for i in inst: # get the slots of the installed packages
+						myslots.add(i.get_env_var("SLOT"))
+
+					myslots.add(self.find_best_match(p).get_env_var("SLOT")) # add the slot of the best package in portage
+					for slot in myslots:
+						new_packages.append(\
+								self.find_best(\
+								[x.get_cpv() for x in self.find_packages("%s:%s" % (i.get_cp(), slot))]\
+								))
+				else:
+					new_packages.append(self.find_best_match(p))
+
+			return new_packages
+							
+		checked = []
+		updating = []
+		raw_checked = []
+		def check (p, add_not_installed = True):
+			"""Checks whether a package is updated or not."""
+			if p.get_cp() in checked: return
+			else: checked.append(p.get_cp())
+
+			appended = False
+			tempDeep = False
+
+			if not p.is_installed():
+				oldList = self.find_installed_packages(p.get_slot_cp())
+				if oldList: 
+					old = oldList[0] # we should only have one package here - else it is a bug
+				else:
+					oldList = self.sort_package_list(self.find_installed_packages(p.get_cp()))
+					if not oldList:
+						if add_not_installed:
+							debug("Not found installed",p.get_cpv(),"==> adding")
+							oldList = [p]
+						else:
+							return
+					old = oldList[-1]
+				
+				updating.append((p, old))
+				appended = True
+				p = old
+
+			if newuse and p.is_installed() and p.is_in_system(): # there is no use to check newuse for a package which is not existing in portage anymore :)
+
+				new_iuse = set(p.get_all_use_flags(installed = False)) # IUSE in the ebuild
+				old_iuse = set(p.get_all_use_flags(installed = True)) # IUSE in the vardb
+				
+				if new_iuse.symmetric_difference(old_iuse): # difference between new_iuse and old_iuse
+					tempDeep = True
+					if not appended:
+						updating.append((p,p))
+						appended = True
+				
+				else:
+					old = set(p.get_installed_use_flags())
+					new = set(p.get_settings("USE").split())
+					
+					if new_iuse.intersection(new) != old_iuse.intersection(old):
+						tempDeep = True
+						if not appended:
+							updating.append((p,p))
+							appended = True
+
+			if deep or tempDeep:
+				states = [(["RDEPEND","PDEPEND"],True), (["DEPEND"], False)]
+				
+				for state in states:
+					for i in p.get_matched_dep_packages(state[0]):
+						if i not in raw_checked:
+							raw_checked.append(i)
+							bm = get_new_packages([i])
+							if not bm: 
+								debug("Bug? No best match could be found:",i)
+							else:
+								for pkg in bm: 
+									if not pkg: continue
+									check(pkg, state[1])
+
+		for p in get_new_packages(packages):
+			if not p: continue # if a masked package is installed we have "None" here
+			check(p, True)
+		
+		return updating
+		
+	use_descs = {}
+	local_use_descs = {}
+	def get_use_desc (self, flag, package = None):
+		# In the first run the dictionaries 'use_descs' and 'local_use_descs' are filled.
+		
+		# fill cache if needed
+		if self.use_descs == {} or self.local_use_descs == {}:
+			# read use.desc
+			fd = open(self.settings.settings["PORTDIR"]+"/profiles/use.desc")
+			lines = fd.readlines()
+			fd.close()
+			for line in lines:
+				line = line.strip()
+				if line != "" and line[0] != '#':
+					fields = [x.strip() for x in line.split(" - ",1)]
+					if len(fields) == 2:
+						self.use_descs[fields[0]] = fields[1]
+
+			# read use.local.desc
+			fd = open(self.settings.settings["PORTDIR"]+"/profiles/use.local.desc")
+			lines = fd.readlines()
+			fd.close()
+			for line in lines:
+				line = line.strip()
+				if line != "" and line[0] != '#':
+					fields = [x.strip() for x in line.split(":",1)]
+					if len(fields) == 2:
+						if not fields[0] in self.local_use_descs: # create
+							self.local_use_descs[fields[0]] = {}
+						subfields = [x.strip() for x in fields[1].split(" - ",1)]
+						if len(subfields) == 2:
+							self.local_use_descs[fields[0]][subfields[0]] = subfields[1]
+		
+		# start
+		desc = None
+		if flag in self.use_descs:
+			desc = self.use_descs[flag]
+		if package != None:
+			if package in self.local_use_descs:
+				if flag in self.local_use_descs[package]:
+					desc = self.local_use_descs[package][flag]
+		return desc
diff --git a/portato/backend/portage_helper.py b/portato/backend/portage_helper.py
deleted file mode 100644
index be4c76c..0000000
--- a/portato/backend/portage_helper.py
+++ /dev/null
@@ -1,467 +0,0 @@
-# -*- coding: utf-8 -*-
-#
-# File: portato/backend/portage_helper.py
-# This file is part of the Portato-Project, a graphical portage-frontend.
-#
-# Copyright (C) 2006-2007 René 'Necoro' Neumann
-# This is free software.  You may redistribute copies of it under the terms of
-# the GNU General Public License version 2.
-# There is NO WARRANTY, to the extent permitted by law.
-#
-# Written by René 'Necoro' Neumann <necoro@necoro.net>
-
-import re, os
-import types
-import portage
-
-from portage_util import unique_array
-
-from portato.backend import portage_settings
-import package
-
-from portato.helper import debug
-
-def find_lambda (name):
-	"""Returns the function needed by all the find_all_*-functions. Returns None if no name is given.
-	
-	@param name: name to build the function of
-	@type name: string
-	@returns: 
-				1. None if no name is given
-				2. a lambda function
-	@rtype: function"""
-	
-	if name != None:
-		return lambda x: re.match(".*"+name+".*",x)
-	else:
-		return lambda x: True
-
-def geneticize_list (list_of_packages):
-	"""Convertes a list of cpv's into L{backend.Package}s.
-	
-	@param list_of_packages: the list of packages
-	@type list_of_packages: list of gentoolkit.Packages
-	@returns: converted list
-	@rtype: backend.Package[]"""
-	
-	return [package.Package(x) for x in list_of_packages]
-
-def find_best (list):
-	"""Returns the best package out of a list of packages.
-
-	@param list: the list of packages to select from
-	@type list: string[]
-	@returns: the best package
-	@rtype: backend.Package"""
-	
-	return package.Package(portage.best(list))
-
-def find_best_match (search_key, only_installed = False):
-	"""Finds the best match in the portage tree. It does not find masked packages!
-	
-	@param search_key: the key to find in the portage tree
-	@type search_key: string
-	@param only_installed: if True, only installed packages are searched
-	@type only_installed: boolean
-	
-	@returns: the package found or None
-	@rtype: backend.Package"""
-
-	t = None
-	if not only_installed:
-		t = portage_settings.porttree.dep_bestmatch(search_key)
-	else:
-		t = portage_settings.vartree.dep_bestmatch(search_key)
-	if t:
-		return package.Package(t)
-	return None
-
-def find_packages (search_key, masked=False):
-	"""This returns a list of packages which have to fit exactly. Additionally ranges like '<,>,=,~,!' et. al. are possible.
-	
-	@param search_key: the key to look for
-	@type search_key: string
-	@param masked: if True, also look for masked packages
-	@type masked: boolean
-	
-	@returns: list of found packages
-	@rtype: backend.Package[]"""
-
-	try:
-		if masked:
-			t = portage_settings.porttree.dbapi.xmatch("match-all", search_key)
-			t += portage_settings.vartree.dbapi.match(search_key)
-		else:
-			t = portage_settings.porttree.dbapi.match(search_key)
-			t += portage_settings.vartree.dbapi.match(search_key)
-	# catch the "ambigous package" Exception
-	except ValueError, e:
-		if type(e[0]) == types.ListType:
-			t = []
-			for cp in e[0]:
-				if masked:
-					t += portage_settings.porttree.dbapi.xmatch("match-all", cp)
-					t += portage_settings.vartree.dbapi.match(cp)
-				else:
-					t += portage_settings.porttree.dbapi.match(cp)
-					t += portage_settings.vartree.dbapi.match(cp)
-		else:
-			raise ValueError(e)
-	# Make the list of packages unique
-	t = unique_array(t)
-	t.sort()
-	return geneticize_list(t)
-
-def find_installed_packages (search_key, masked=False):
-	"""This returns a list of packages which have to fit exactly. Additionally ranges like '<,>,=,~,!' et. al. are possible.
-	
-	@param search_key: the key to look for
-	@type search_key: string
-	@param masked: if True, also look for masked packages
-	@type masked: boolean
-	
-	@returns: list of found packages
-	@rtype: backend.Package[]"""
-
-	try:
-		t = portage_settings.vartree.dbapi.match(search_key)
-	# catch the "ambigous package" Exception
-	except ValueError, e:
-		if type(e[0]) == types.ListType:
-			t = []
-			for cp in e[0]:
-				t += portage_settings.vartree.dbapi.match(cp)
-		else:
-			raise ValueError(e)
-
-	return geneticize_list(t)
-
-def find_system_packages ():
-	"""Looks for all packages saved as "system-packages".
-	
-	@returns: a tuple of (resolved_packages, unresolved_packages).
-	@rtype: (backend.Package[], backend.Package[])"""
-
-	pkglist = portage_settings.settings.packages
-	resolved = []
-	unresolved = []
-	for x in pkglist:
-		cpv = x.strip()
-		if len(cpv) and cpv[0] == "*":
-			pkg = find_best_match(cpv)
-			if pkg:
-				resolved.append(pkg)
-			else:
-				unresolved.append(cpv)
-	return (resolved, geneticize_list(unresolved))
-
-def find_world_packages ():
-	"""Looks for all packages saved in the world-file.
-	
-	@returns: a tuple of (resolved_packages, unresolved_packages).
-	@rtype: (backend.Package[], backend.Package[])"""
-
-	f = open(portage.WORLD_FILE)
-	pkglist = f.readlines()
-	resolved = []
-	unresolved = []
-	for x in pkglist:
-		cpv = x.strip()
-		if len(cpv) and cpv[0] != "#":
-			pkg = find_best_match(cpv)
-			if pkg:
-				resolved.append(pkg)
-			else:
-				unresolved.append(cpv)
-	return (resolved, geneticize_list(unresolved))
-
-def find_all_installed_packages (name=None, withVersion=True):
-	"""Finds all installed packages matching a name or all if no name is specified.
-
-	@param name: the name to look for - it is expanded to .*name.* ; if None, all packages are returned
-	@type name: string or None
-	@param withVersion: if True version-specific packages are returned; else only the cat/package-strings a delivered
-	@type withVersion: boolean
-
-	@returns: all packages/cp-strings found
-	@rtype: backend.Package[] or cp-string[]"""
-
-	if withVersion:
-		t = portage_settings.vartree.dbapi.cpv_all()
-		if name:
-			t = filter(find_lambda(name),t)
-		return geneticize_list(t)
-	
-	else:
-		t = portage_settings.vartree.dbapi.cp_all()
-		if name:
-			t = filter(find_lambda(name),t)
-		return t
-
-def find_all_uninstalled_packages (name=None):
-	"""Finds all uninstalled packages matching a name or all if no name is specified.
-
-	@param name: the name to look for - it is expanded to .*name.* ; if None, all packages are returned
-	@type name: string or None
-	@returns: all packages found
-	@rtype: backend.Package[]"""
-
-	alist = find_all_packages(name)
-	return geneticize_list([x for x in alist if not x.is_installed()])	
-
-def find_all_packages (name=None, withVersion=True):
-	"""Finds all packages matching a name or all if no name is specified.
-
-	@param name: the name to look for - it is expanded to .*name.* ; if None, all packages are returned
-	@type name: string or None
-	@param withVersion: if True version-specific packages are returned; else only the cat/package-strings a delivered
-	@type withVersion: boolean
-
-	@returns: all packages/cp-strings found
-	@rtype: backend.Package[] or cp-string[]"""
-	
-	t = portage_settings.porttree.dbapi.cp_all()
-	t += portage_settings.vartree.dbapi.cp_all()
-	if name:
-		t = filter(find_lambda(name),t)
-	t = unique_array(t)
-	
-	if (withVersion):
-		t2 = []
-		for x in t:
-			t2 += portage_settings.porttree.dbapi.cp_list(x)
-			t2 += portage_settings.vartree.dbapi.cp_list(x)
-			t2 = unique_array(t2)
-		return geneticize_list(t2)
-	else:
-		return t;
-
-def find_all_world_packages (name=None):
-	"""Finds all world packages matching a name or all if no name is specified.
-
-	@param name: the name to look for - it is expanded to .*name.* ; if None, all packages are returned
-	@type name: string or None
-	@returns: all packages found
-	@rtype: backend.Package[]"""
-
-	world = filter(find_lambda(name), [x.get_cpv() for x in find_world_packages()[0]])
-	world = unique_array(world)
-	return geneticize_list(world)
-
-def find_all_system_packages (name=None):
-	"""Finds all system packages matching a name or all if no name is specified.
-
-	@param name: the name to look for - it is expanded to .*name.* ; if None, all packages are returned
-	@type name: string or None
-	@returns: all packages found
-	@rtype: backend.Package[]"""
-
-	sys = filter(find_lambda(name), [x.get_cpv() for x in find_system_packages()[0]])
-	sys = unique_array(sys)
-	return geneticize_list(sys)
-
-def list_categories (name=None):
-	"""Finds all categories matching a name or all if no name is specified.
-
-	@param name: the name to look for - it is expanded to .*name.* ; if None, all categories are returned
-	@type name: string or None
-	@returns: all categories found
-	@rtype: string[]"""
-
-	categories = portage_settings.settings.categories
-	return filter(find_lambda(name), categories)
-
-def split_package_name (name):
-	"""Splits a package name in its elements.
-
-	@param name: name to split
-	@type name: string
-	@returns: list: [category, name, version, rev] whereby rev is "r0" if not specified in the name
-	@rtype: string[]"""
-	
-	r = portage.catpkgsplit(portage.dep_getcpv(name))
-	if not r:
-		r = name.split("/")
-		if len(r) == 1:
-			return ["", name, "", "r0"]
-		else:
-			return r + ["", "r0"]
-	if r[0] == 'null':
-		r[0] = ''
-	return r
-
-def sort_package_list(pkglist):
-	"""Sorts a package list in the same manner portage does.
-	
-	@param pkglist: list to sort
-	@type pkglist: Packages[]"""
-	
-	pkglist.sort(package.Package.compare_version)
-	return pkglist
-
-def reload_settings ():
-	"""Reloads portage."""
-	portage_settings.load()
-
-def update_world (newuse = False, deep = False):
-	"""Calculates the packages to get updated in an update world.
-
-	@param newuse: Checks if a use-flag has a different state then to install time.
-	@type newuse: boolean
-	@param deep: Not only check world packages but also there dependencies.
-	@type deep: boolean
-	@returns: a list containing of the tuple (new_package, old_package)
-	@rtype: (backend.Package, backend.Package)[]"""
-
-	# read world file
-	world = open(portage.WORLD_FILE)
-	packages = []
-	for line in world:
-		line = line.strip()
-		if len(line) == 0: continue # empty line
-		if line[0] == "#": continue # comment
-		packages.append(line)
-	world.close()
-
-	# append system packages
-	packages.extend(unique_array([p.get_cp() for p in find_all_system_packages()]))
-
-	def get_new_packages (packages):
-		new_packages = []
-		for p in packages:
-			inst = find_installed_packages(p)
-			if len(inst) > 1:
-				myslots = set()
-				for i in inst: # get the slots of the installed packages
-					myslots.add(i.get_env_var("SLOT"))
-
-				myslots.add(find_best_match(p).get_env_var("SLOT")) # add the slot of the best package in portage
-				for slot in myslots:
-					new_packages.append(\
-							find_best(\
-							[x.get_cpv() for x in find_packages("%s:%s" % (i.get_cp(), slot))]\
-							))
-			else:
-				new_packages.append(find_best_match(p))
-
-		return new_packages
-						
-	checked = []
-	updating = []
-	raw_checked = []
-	def check (p, add_not_installed = True):
-		"""Checks whether a package is updated or not."""
-		if p.get_cp() in checked: return
-		else: checked.append(p.get_cp())
-
-		appended = False
-		tempDeep = False
-
-		if not p.is_installed():
-			oldList = find_installed_packages(p.get_slot_cp())
-			if oldList: 
-				old = oldList[0] # we should only have one package here - else it is a bug
-			else:
-				oldList = sort_package_list(find_installed_packages(p.get_cp()))
-				if not oldList:
-					if add_not_installed:
-						debug("Not found installed",p.get_cpv(),"==> adding")
-						oldList = [p]
-					else:
-						return
-				old = oldList[-1]
-			
-			updating.append((p, old))
-			appended = True
-			p = old
-
-		if newuse and p.is_installed() and p.is_in_system(): # there is no use to check newuse for a package which is not existing in portage anymore :)
-
-			new_iuse = set(p.get_all_use_flags(installed = False)) # IUSE in the ebuild
-			old_iuse = set(p.get_all_use_flags(installed = True)) # IUSE in the vardb
-			
-			if new_iuse.symmetric_difference(old_iuse): # difference between new_iuse and old_iuse
-				tempDeep = True
-				if not appended:
-					updating.append((p,p))
-					appended = True
-			
-			else:
-				old = set(p.get_installed_use_flags())
-				new = set(p.get_settings("USE").split())
-				
-				if new_iuse.intersection(new) != old_iuse.intersection(old):
-					tempDeep = True
-					if not appended:
-						updating.append((p,p))
-						appended = True
-
-		if deep or tempDeep:
-			states = [(["RDEPEND","PDEPEND"],True), (["DEPEND"], False)]
-			
-			for state in states:
-				for i in p.get_matched_dep_packages(state[0]):
-					if i not in raw_checked:
-						raw_checked.append(i)
-						bm = get_new_packages([i])
-						if not bm: 
-							debug("Bug? No best match could be found:",i)
-						else:
-							for pkg in bm: 
-								if not pkg: continue
-								check(pkg, state[1])
-
-	for p in get_new_packages(packages):
-		if not p: continue # if a masked package is installed we have "None" here
-		check(p, True)
-	
-	return updating
-	
-use_descs = {}
-local_use_descs = {}
-def get_use_desc (flag, package = None):
-	"""Returns the description of a specific useflag or None if no desc was found. 
-	If a package is given (in the <cat>/<name> format) the local use descriptions are searched too.
-	
-	@param flag: flag to get the description for
-	@type flag: string
-	@param package: name of a package: if given local use descriptions are searched too
-	@type package: cp-string
-	@returns: found description
-	@rtype: string"""
-	
-	# In the first run the dictionaries 'use_descs' and 'local_use_descs' are filled.
-	
-	# fill cache if needed
-	if use_descs == {} or local_use_descs == {}:
-		# read use.desc
-		fd = open(portage_settings.settings["PORTDIR"]+"/profiles/use.desc")
-		for line in fd.readlines():
-			line = line.strip()
-			if line != "" and line[0] != '#':
-				fields = [x.strip() for x in line.split(" - ",1)]
-				if len(fields) == 2:
-					use_descs[fields[0]] = fields[1]
-
-		# read use.local.desc
-		fd = open(portage_settings.settings["PORTDIR"]+"/profiles/use.local.desc")
-		for line in fd.readlines():
-			line = line.strip()
-			if line != "" and line[0] != '#':
-				fields = [x.strip() for x in line.split(":",1)]
-				if len(fields) == 2:
-					if not fields[0] in local_use_descs: # create
-						local_use_descs[fields[0]] = {}
-					subfields = [x.strip() for x in fields[1].split(" - ",1)]
-					if len(subfields) == 2:
-						local_use_descs[fields[0]][subfields[0]] = subfields[1]
-	
-	# start
-	desc = None
-	if flag in use_descs:
-		desc = use_descs[flag]
-	if package != None:
-		if package in local_use_descs:
-			if flag in local_use_descs[package]:
-				desc = local_use_descs[package][flag]
-	return desc
diff --git a/portato/backend/system_interface.py b/portato/backend/system_interface.py
new file mode 100644
index 0000000..eb81401
--- /dev/null
+++ b/portato/backend/system_interface.py
@@ -0,0 +1,283 @@
+# -*- coding: utf-8 -*-
+#
+# File: portato/backend/system_interface.py
+# This file is part of the Portato-Project, a graphical portage-frontend.
+#
+# Copyright (C) 2007 René 'Necoro' Neumann
+# This is free software.  You may redistribute copies of it under the terms of
+# the GNU General Public License version 2.
+# There is NO WARRANTY, to the extent permitted by law.
+#
+# Written by René 'Necoro' Neumann <necoro@necoro.net>
+
+class SystemInterface:
+
+	def split_cpv (self, cpv):
+		"""Splits a cpv into all its parts.
+
+		@param cpv: the cpv to split
+		@type cpv: string
+		@returns: the splitted cpv
+		@rtype: string[]"""
+
+		raise NotImplementedError
+	
+	def find_best(self, list):
+		"""Returns the best package out of a list of packages.
+
+		@param list: the list of packages to select from
+		@type list: string[]
+		@returns: the best package
+		@rtype: backend.Package"""
+		
+		raise NotImplementedError
+
+	def find_best_match (self, search_key, only_installed = False):
+		"""Finds the best match in the portage tree. It does not find masked packages!
+		
+		@param search_key: the key to find in the portage tree
+		@type search_key: string
+		@param only_installed: if True, only installed packages are searched
+		@type only_installed: boolean
+		
+		@returns: the package found or None
+		@rtype: backend.Package"""
+
+		raise NotImplementedError
+
+	def find_packages (self, search_key, masked=False):
+		"""This returns a list of packages which have to fit exactly. Additionally ranges like '<,>,=,~,!' et. al. are possible.
+		
+		@param search_key: the key to look for
+		@type search_key: string
+		@param masked: if True, also look for masked packages
+		@type masked: boolean
+		
+		@returns: list of found packages
+		@rtype: backend.Package[]"""
+
+		raise NotImplementedError
+
+
+	def find_installed_packages (self, search_key, masked = False):
+		"""This returns a list of packages which have to fit exactly. Additionally ranges like '<,>,=,~,!' et. al. are possible.
+		
+		@param search_key: the key to look for
+		@type search_key: string
+		@param masked: if True, also look for masked packages
+		@type masked: boolean
+		
+		@returns: list of found packages
+		@rtype: backend.Package[]"""
+
+		raise NotImplementedError
+
+	def find_system_packages (self):
+		"""Looks for all packages saved as "system-packages".
+		
+		@returns: a tuple of (resolved_packages, unresolved_packages).
+		@rtype: (backend.Package[], backend.Package[])"""
+
+		raise NotImplementedError
+
+	def find_world_packages (self):
+		"""Looks for all packages saved in the world-file.
+		
+		@returns: a tuple of (resolved_packages, unresolved_packages).
+		@rtype: (backend.Package[], backend.Package[])"""
+
+		raise NotImplementedError
+
+	def find_all_installed_packages (self, name = None, withVersion = True):
+		"""Finds all installed packages matching a name or all if no name is specified.
+
+		@param name: the name to look for - it is expanded to .*name.* ; if None, all packages are returned
+		@type name: string or None
+		@param withVersion: if True version-specific packages are returned; else only the cat/package-strings a delivered
+		@type withVersion: boolean
+
+		@returns: all packages/cp-strings found
+		@rtype: backend.Package[] or cp-string[]"""
+
+		raise NotImplementedError
+
+	def find_all_uninstalled_packages (self, name = None):
+		"""Finds all uninstalled packages matching a name or all if no name is specified.
+
+		@param name: the name to look for - it is expanded to .*name.* ; if None, all packages are returned
+		@type name: string or None
+		@returns: all packages found
+		@rtype: backend.Package[]"""
+
+		raise NotImplementedError
+
+	def find_all_packages (self, name = None, withVersion = True):
+		"""Finds all packages matching a name or all if no name is specified.
+
+		@param name: the name to look for - it is expanded to .*name.* ; if None, all packages are returned
+		@type name: string or None
+		@param withVersion: if True version-specific packages are returned; else only the cat/package-strings a delivered
+		@type withVersion: boolean
+
+		@returns: all packages/cp-strings found
+		@rtype: backend.Package[] or cp-string[]"""
+
+		raise NotImplementedError
+		
+	def find_all_world_packages (self, name = None):
+		"""Finds all world packages matching a name or all if no name is specified.
+
+		@param name: the name to look for - it is expanded to .*name.* ; if None, all packages are returned
+		@type name: string or None
+		@returns: all packages found
+		@rtype: backend.Package[]"""
+
+		raise NotImplementedError
+
+	def find_all_system_packages (self, name = None):
+		"""Finds all system packages matching a name or all if no name is specified.
+
+		@param name: the name to look for - it is expanded to .*name.* ; if None, all packages are returned
+		@type name: string or None
+		@returns: all packages found
+		@rtype: backend.Package[]"""
+
+		raise NotImplementedError
+
+	def list_categories (self, name = None):
+		"""Finds all categories matching a name or all if no name is specified.
+
+		@param name: the name to look for - it is expanded to .*name.* ; if None, all categories are returned
+		@type name: string or None
+		@returns: all categories found
+		@rtype: string[]"""
+
+		raise NotImplementedError
+
+	def sort_package_list(self, pkglist):
+		"""Sorts a package list in the same manner portage does.
+		
+		@param pkglist: list to sort
+		@type pkglist: Packages[]"""
+
+		raise NotImplementedError
+		
+	def reload_settings (self):
+		"""Reloads portage."""
+
+		raise NotImplementedError
+
+	def update_world (self, newuse = False, deep = False):
+		"""Calculates the packages to get updated in an update world.
+
+		@param newuse: Checks if a use-flag has a different state then to install time.
+		@type newuse: boolean
+		@param deep: Not only check world packages but also there dependencies.
+		@type deep: boolean
+		@returns: a list containing of the tuple (new_package, old_package)
+		@rtype: (backend.Package, backend.Package)[]"""
+
+		raise NotImplementedError
+
+	def get_use_desc (self, flag, package = None):
+		"""Returns the description of a specific useflag or None if no desc was found. 
+		If a package is given (in the <cat>/<name> format) the local use descriptions are searched too.
+		
+		@param flag: flag to get the description for
+		@type flag: string
+		@param package: name of a package: if given local use descriptions are searched too
+		@type package: cp-string
+		@returns: found description
+		@rtype: string"""
+
+		raise NotImplementedError
+
+	def new_package (self, cpv):
+		"""Returns an instance of the appropriate Package-Subclass.
+
+		@param cpv: the cpv to create the package from
+		@type cpv: string
+		@returns: a new Package-object.
+		@rtype: Package"""
+
+		raise NotImplementedError
+
+	def get_config_path (self):
+		"""Returns the actual path to the config files.
+		
+		@returns: the path, e.g. /etc/portage
+		@rtyoe: string"""
+
+		raise NotImplementedError
+
+	def get_world_file_path (self):
+		"""Returns the path to the world file.
+
+		@returns: the path of the world file
+		@rtype: string"""
+
+		raise NotImplementedError
+
+	def get_sync_command (self):
+		"""Returns the command(s) to run for syncing. This can be overridden by the user.
+
+		@returns: command to run
+		@rtype: string[]"""
+
+		raise NotImplementedError
+
+	def get_merge_command (self):
+		"""Returns the command(s) to run for the merging.
+
+		@returns: command to run
+		@rtype: string[]"""
+
+		raise NotImplementedError
+
+	def get_oneshot_option (self):
+		"""Returns the options to append for marking a merge as "oneshot".
+
+		@returns: option(s) to append
+		@rtype: string[]"""
+
+		raise NotImplementedError
+
+	def get_newuse_option (self):
+		"""Returns the options to append for marking a merge as "newuse".
+
+		@returns: option(s) to append
+		@rtype: string[]"""
+
+		raise NotImplementedError
+
+	def get_deep_option (self):
+		"""Returns the options to append for marking a merge as "deep".
+
+		@returns: option(s) to append
+		@rtype: string[]"""
+
+		raise NotImplementedError
+
+	def get_update_option (self):
+		"""Returns the options to append for marking a merge as "update".
+
+		@returns: option(s) to append
+		@rtype: string[]"""
+
+		raise NotImplementedError
+
+	def get_pretend_option (self):
+		"""Returns the options to append for marking a merge as "pretend".
+
+		@returns: option(s) to append
+		@rtype: string[]"""
+
+		raise NotImplementedError
+
+	def get_unmerge_option (self):
+		"""Returns the options to append for marking a merge as "unmerge".
+
+		@returns: option(s) to append
+		@rtype: string[]"""
+
+		raise NotImplementedError
diff --git a/portato/gui/gtk/TreeViewTooltips.py b/portato/gui/gtk/TreeViewTooltips.py
index 1112d3e..120d4df 100644
--- a/portato/gui/gtk/TreeViewTooltips.py
+++ b/portato/gui/gtk/TreeViewTooltips.py
@@ -292,7 +292,7 @@ class TreeViewTooltips:
     def get_tooltip(self, view, column, path):
         'See the module doc string for a description of this method'
         
-        raise NotImplemented, 'Subclass must implement get_tooltip()'
+        raise NotImplementedError, 'Subclass must implement get_tooltip()'
 
 
 if __name__ == '__main__':
diff --git a/portato/gui/gtk/glade/portato.glade b/portato/gui/gtk/glade/portato.glade
index f99be90..c8695c3 100644
--- a/portato/gui/gtk/glade/portato.glade
+++ b/portato/gui/gtk/glade/portato.glade
@@ -392,72 +392,48 @@
                     <property name="n_rows">4</property>
                     <property name="n_columns">2</property>
                     <child>
-                      <widget class="GtkScrolledWindow" id="useListScroll">
+                      <widget class="GtkHBox" id="checkHB">
                         <property name="visible">True</property>
-                        <property name="hscrollbar_policy">GTK_POLICY_AUTOMATIC</property>
-                        <property name="vscrollbar_policy">GTK_POLICY_AUTOMATIC</property>
+                        <property name="spacing">1</property>
+                        <property name="homogeneous">True</property>
                         <child>
-                          <widget class="GtkTreeView" id="useList">
+                          <widget class="GtkCheckButton" id="installedCheck">
                             <property name="visible">True</property>
+                            <property name="no_show_all">True</property>
+                            <property name="label" translatable="yes">Installed</property>
+                            <property name="draw_indicator">True</property>
+                            <signal name="button_press_event" handler="cb_button_pressed"/>
                           </widget>
+                          <packing>
+                            <property name="fill">False</property>
+                          </packing>
                         </child>
-                      </widget>
-                      <packing>
-                        <property name="right_attach">2</property>
-                        <property name="top_attach">2</property>
-                        <property name="bottom_attach">3</property>
-                        <property name="x_padding">5</property>
-                        <property name="y_padding">5</property>
-                      </packing>
-                    </child>
-                    <child>
-                      <widget class="GtkVBox" id="comboVB">
-                        <property name="visible">True</property>
                         <child>
-                          <placeholder/>
+                          <widget class="GtkCheckButton" id="maskedCheck">
+                            <property name="visible">True</property>
+                            <property name="no_show_all">True</property>
+                            <property name="label" translatable="yes">Masked</property>
+                            <property name="draw_indicator">True</property>
+                            <signal name="toggled" handler="cb_masked_toggled"/>
+                          </widget>
+                          <packing>
+                            <property name="fill">False</property>
+                            <property name="position">1</property>
+                          </packing>
+                        </child>
+                        <child>
+                          <widget class="GtkCheckButton" id="testingCheck">
+                            <property name="visible">True</property>
+                            <property name="no_show_all">True</property>
+                            <property name="label" translatable="yes">Testing</property>
+                            <property name="draw_indicator">True</property>
+                            <signal name="toggled" handler="cb_testing_toggled"/>
+                          </widget>
+                          <packing>
+                            <property name="fill">False</property>
+                            <property name="position">2</property>
+                          </packing>
                         </child>
-                      </widget>
-                      <packing>
-                        <property name="top_attach">1</property>
-                        <property name="bottom_attach">2</property>
-                        <property name="y_options">GTK_FILL</property>
-                        <property name="x_padding">5</property>
-                      </packing>
-                    </child>
-                    <child>
-                      <widget class="GtkLabel" id="descLabel">
-                        <property name="visible">True</property>
-                        <property name="justify">GTK_JUSTIFY_CENTER</property>
-                        <property name="wrap">True</property>
-                      </widget>
-                      <packing>
-                        <property name="right_attach">2</property>
-                        <property name="x_options">GTK_FILL</property>
-                        <property name="y_options"></property>
-                        <property name="y_padding">10</property>
-                      </packing>
-                    </child>
-                    <child>
-                      <widget class="GtkLabel" id="missingLabel">
-                        <property name="visible">True</property>
-                        <property name="no_show_all">True</property>
-                        <property name="label" translatable="yes">&lt;span foreground='red'&gt;&lt;b&gt;MISSING KEYWORD&lt;/b&gt;&lt;/span&gt;</property>
-                        <property name="use_markup">True</property>
-                      </widget>
-                      <packing>
-                        <property name="left_attach">1</property>
-                        <property name="right_attach">2</property>
-                        <property name="top_attach">1</property>
-                        <property name="bottom_attach">2</property>
-                        <property name="y_options">GTK_FILL</property>
-                      </packing>
-                    </child>
-                    <child>
-                      <widget class="GtkLabel" id="notInSysLabel">
-                        <property name="visible">True</property>
-                        <property name="no_show_all">True</property>
-                        <property name="label" translatable="yes">&lt;b&gt;Installed, but not in portage anymore&lt;/b&gt;</property>
-                        <property name="use_markup">True</property>
                       </widget>
                       <packing>
                         <property name="left_attach">1</property>
@@ -522,55 +498,79 @@
                       </packing>
                     </child>
                     <child>
-                      <widget class="GtkHBox" id="checkHB">
+                      <widget class="GtkLabel" id="notInSysLabel">
+                        <property name="visible">True</property>
+                        <property name="no_show_all">True</property>
+                        <property name="label" translatable="yes">&lt;b&gt;Installed, but not in portage anymore&lt;/b&gt;</property>
+                        <property name="use_markup">True</property>
+                      </widget>
+                      <packing>
+                        <property name="left_attach">1</property>
+                        <property name="right_attach">2</property>
+                        <property name="top_attach">1</property>
+                        <property name="bottom_attach">2</property>
+                        <property name="y_options">GTK_FILL</property>
+                      </packing>
+                    </child>
+                    <child>
+                      <widget class="GtkLabel" id="missingLabel">
+                        <property name="visible">True</property>
+                        <property name="no_show_all">True</property>
+                        <property name="label" translatable="yes">&lt;span foreground='red'&gt;&lt;b&gt;MISSING KEYWORD&lt;/b&gt;&lt;/span&gt;</property>
+                        <property name="use_markup">True</property>
+                      </widget>
+                      <packing>
+                        <property name="left_attach">1</property>
+                        <property name="right_attach">2</property>
+                        <property name="top_attach">1</property>
+                        <property name="bottom_attach">2</property>
+                        <property name="y_options">GTK_FILL</property>
+                      </packing>
+                    </child>
+                    <child>
+                      <widget class="GtkLabel" id="descLabel">
+                        <property name="visible">True</property>
+                        <property name="justify">GTK_JUSTIFY_CENTER</property>
+                        <property name="wrap">True</property>
+                      </widget>
+                      <packing>
+                        <property name="right_attach">2</property>
+                        <property name="x_options">GTK_FILL</property>
+                        <property name="y_options"></property>
+                        <property name="y_padding">10</property>
+                      </packing>
+                    </child>
+                    <child>
+                      <widget class="GtkVBox" id="comboVB">
                         <property name="visible">True</property>
-                        <property name="spacing">1</property>
-                        <property name="homogeneous">True</property>
-                        <child>
-                          <widget class="GtkCheckButton" id="installedCheck">
-                            <property name="visible">True</property>
-                            <property name="no_show_all">True</property>
-                            <property name="label" translatable="yes">Installed</property>
-                            <property name="draw_indicator">True</property>
-                            <signal name="button_press_event" handler="cb_button_pressed"/>
-                          </widget>
-                          <packing>
-                            <property name="fill">False</property>
-                          </packing>
-                        </child>
                         <child>
-                          <widget class="GtkCheckButton" id="maskedCheck">
-                            <property name="visible">True</property>
-                            <property name="no_show_all">True</property>
-                            <property name="label" translatable="yes">Masked</property>
-                            <property name="draw_indicator">True</property>
-                            <signal name="toggled" handler="cb_masked_toggled"/>
-                          </widget>
-                          <packing>
-                            <property name="fill">False</property>
-                            <property name="position">1</property>
-                          </packing>
+                          <placeholder/>
                         </child>
+                      </widget>
+                      <packing>
+                        <property name="top_attach">1</property>
+                        <property name="bottom_attach">2</property>
+                        <property name="y_options">GTK_FILL</property>
+                        <property name="x_padding">5</property>
+                      </packing>
+                    </child>
+                    <child>
+                      <widget class="GtkScrolledWindow" id="useListScroll">
+                        <property name="visible">True</property>
+                        <property name="hscrollbar_policy">GTK_POLICY_AUTOMATIC</property>
+                        <property name="vscrollbar_policy">GTK_POLICY_AUTOMATIC</property>
                         <child>
-                          <widget class="GtkCheckButton" id="testingCheck">
+                          <widget class="GtkTreeView" id="useList">
                             <property name="visible">True</property>
-                            <property name="no_show_all">True</property>
-                            <property name="label" translatable="yes">Testing</property>
-                            <property name="draw_indicator">True</property>
-                            <signal name="toggled" handler="cb_testing_toggled"/>
                           </widget>
-                          <packing>
-                            <property name="fill">False</property>
-                            <property name="position">2</property>
-                          </packing>
                         </child>
                       </widget>
                       <packing>
-                        <property name="left_attach">1</property>
                         <property name="right_attach">2</property>
-                        <property name="top_attach">1</property>
-                        <property name="bottom_attach">2</property>
-                        <property name="y_options">GTK_FILL</property>
+                        <property name="top_attach">2</property>
+                        <property name="bottom_attach">3</property>
+                        <property name="x_padding">5</property>
+                        <property name="y_padding">5</property>
                       </packing>
                     </child>
                   </widget>
@@ -845,6 +845,68 @@
           </widget>
         </child>
         <child>
+          <widget class="GtkFrame" id="systemFrame">
+            <property name="visible">True</property>
+            <property name="label_xalign">0</property>
+            <child>
+              <widget class="GtkAlignment" id="alignment6">
+                <property name="visible">True</property>
+                <property name="left_padding">12</property>
+                <child>
+                  <widget class="GtkHButtonBox" id="systemButtonBox">
+                    <property name="visible">True</property>
+                    <child>
+                      <widget class="GtkRadioButton" id="portageRadio">
+                        <property name="visible">True</property>
+                        <property name="label" translatable="yes">Portage</property>
+                        <property name="active">True</property>
+                        <property name="draw_indicator">True</property>
+                      </widget>
+                    </child>
+                    <child>
+                      <widget class="GtkRadioButton" id="pkgCoreRadio">
+                        <property name="visible">True</property>
+                        <property name="sensitive">False</property>
+                        <property name="label" translatable="yes">pkgCore</property>
+                        <property name="draw_indicator">True</property>
+                        <property name="group">portageRadio</property>
+                      </widget>
+                      <packing>
+                        <property name="position">1</property>
+                      </packing>
+                    </child>
+                    <child>
+                      <widget class="GtkRadioButton" id="paludisRadio">
+                        <property name="visible">True</property>
+                        <property name="sensitive">False</property>
+                        <property name="label" translatable="yes">Paludis</property>
+                        <property name="draw_indicator">True</property>
+                        <property name="group">portageRadio</property>
+                      </widget>
+                      <packing>
+                        <property name="position">2</property>
+                      </packing>
+                    </child>
+                  </widget>
+                </child>
+              </widget>
+            </child>
+            <child>
+              <widget class="GtkLabel" id="label7">
+                <property name="visible">True</property>
+                <property name="label" translatable="yes">&lt;b&gt;System Options&lt;/b&gt;</property>
+                <property name="use_markup">True</property>
+              </widget>
+              <packing>
+                <property name="type">label_item</property>
+              </packing>
+            </child>
+          </widget>
+          <packing>
+            <property name="position">1</property>
+          </packing>
+        </child>
+        <child>
           <widget class="GtkFrame" id="syncFrame">
             <property name="visible">True</property>
             <property name="label_xalign">0</property>
@@ -890,7 +952,7 @@
             </child>
           </widget>
           <packing>
-            <property name="position">1</property>
+            <property name="position">2</property>
           </packing>
         </child>
         <child>
@@ -941,7 +1003,7 @@
             </child>
           </widget>
           <packing>
-            <property name="position">2</property>
+            <property name="position">3</property>
           </packing>
         </child>
         <child>
@@ -969,186 +1031,186 @@
                       <placeholder/>
                     </child>
                     <child>
-                      <widget class="GtkLabel" id="maskLabel">
-                        <property name="visible">True</property>
-                        <property name="xalign">0</property>
-                        <property name="xpad">5</property>
-                        <property name="label" translatable="yes">&lt;u&gt;&lt;i&gt;Masking Keywords&lt;/i&gt;&lt;/u&gt;</property>
-                        <property name="use_markup">True</property>
-                        <property name="single_line_mode">True</property>
-                      </widget>
-                      <packing>
-                        <property name="top_attach">7</property>
-                        <property name="bottom_attach">8</property>
-                        <property name="y_padding">5</property>
-                      </packing>
-                    </child>
-                    <child>
-                      <widget class="GtkLabel" id="testLabel">
+                      <widget class="GtkEntry" id="useFileEdit">
                         <property name="visible">True</property>
-                        <property name="xalign">0</property>
-                        <property name="xpad">5</property>
-                        <property name="label" translatable="yes">&lt;u&gt;&lt;i&gt;Testing Keywords&lt;/i&gt;&lt;/u&gt;</property>
-                        <property name="use_markup">True</property>
-                        <property name="single_line_mode">True</property>
                       </widget>
                       <packing>
-                        <property name="top_attach">4</property>
-                        <property name="bottom_attach">5</property>
-                        <property name="y_padding">5</property>
+                        <property name="left_attach">1</property>
+                        <property name="right_attach">2</property>
+                        <property name="top_attach">3</property>
+                        <property name="bottom_attach">4</property>
                       </packing>
                     </child>
                     <child>
-                      <widget class="GtkLabel" id="useLabel">
+                      <widget class="GtkLabel" id="useEditLabel">
                         <property name="visible">True</property>
                         <property name="xalign">0</property>
-                        <property name="xpad">5</property>
-                        <property name="label" translatable="yes">&lt;u&gt;&lt;i&gt;Use-Flags&lt;/i&gt;&lt;/u&gt;</property>
-                        <property name="use_markup">True</property>
+                        <property name="label" translatable="yes">File name to use, if package.use is a directory: </property>
                         <property name="single_line_mode">True</property>
                       </widget>
                       <packing>
-                        <property name="top_attach">1</property>
-                        <property name="bottom_attach">2</property>
-                        <property name="y_padding">6</property>
+                        <property name="top_attach">3</property>
+                        <property name="bottom_attach">4</property>
                       </packing>
                     </child>
                     <child>
-                      <widget class="GtkEventBox" id="hintEB">
+                      <widget class="GtkCheckButton" id="usePerVersionCheck">
                         <property name="visible">True</property>
-                        <child>
-                          <widget class="GtkFrame" id="hintFrame">
-                            <property name="visible">True</property>
-                            <property name="label_xalign">0</property>
-                            <property name="shadow_type">GTK_SHADOW_OUT</property>
-                            <child>
-                              <widget class="GtkLabel" id="hintLabel">
-                                <property name="visible">True</property>
-                                <property name="xalign">0</property>
-                                <property name="label" translatable="yes">&lt;u&gt;You may use the following placeholders:&lt;/u&gt;
-
-																	&lt;i&gt;$(cat)&lt;/i&gt;: category
-																	&lt;i&gt;$(pkg)&lt;/i&gt;: package name
-																	&lt;i&gt;$(cat-1)/$(cat-2)&lt;/i&gt;: first/second part of the category</property>
-                                <property name="use_markup">True</property>
-                              </widget>
-                            </child>
-                            <child>
-                              <placeholder/>
-                              <packing>
-                                <property name="type">label_item</property>
-                              </packing>
-                            </child>
-                          </widget>
-                        </child>
+                        <property name="label" translatable="yes">Add only exact version to package.use</property>
+                        <property name="draw_indicator">True</property>
                       </widget>
                       <packing>
                         <property name="right_attach">2</property>
+                        <property name="top_attach">2</property>
+                        <property name="bottom_attach">3</property>
                       </packing>
                     </child>
                     <child>
-                      <widget class="GtkCheckButton" id="maskPerVersionCheck">
+                      <widget class="GtkCheckButton" id="testPerVersionCheck">
                         <property name="visible">True</property>
-                        <property name="label" translatable="yes">Add only exact version to package.mask/package.unmask</property>
+                        <property name="label" translatable="yes">Add only exact version to package.keywords</property>
                         <property name="draw_indicator">True</property>
                       </widget>
                       <packing>
                         <property name="right_attach">2</property>
-                        <property name="top_attach">8</property>
-                        <property name="bottom_attach">9</property>
+                        <property name="top_attach">5</property>
+                        <property name="bottom_attach">6</property>
                       </packing>
                     </child>
                     <child>
-                      <widget class="GtkLabel" id="maskEditLabel">
+                      <widget class="GtkLabel" id="testEditLabel">
                         <property name="visible">True</property>
                         <property name="xalign">0</property>
-                        <property name="label" translatable="yes">File name to use, if package.mask/package.unmask is a directory: </property>
+                        <property name="label" translatable="yes">File name to use, if package.keywords is a directory: </property>
                         <property name="single_line_mode">True</property>
                       </widget>
                       <packing>
-                        <property name="top_attach">9</property>
-                        <property name="bottom_attach">10</property>
+                        <property name="top_attach">6</property>
+                        <property name="bottom_attach">7</property>
                       </packing>
                     </child>
                     <child>
-                      <widget class="GtkEntry" id="maskFileEdit">
+                      <widget class="GtkEntry" id="testFileEdit">
                         <property name="visible">True</property>
                       </widget>
                       <packing>
                         <property name="left_attach">1</property>
                         <property name="right_attach">2</property>
-                        <property name="top_attach">9</property>
-                        <property name="bottom_attach">10</property>
+                        <property name="top_attach">6</property>
+                        <property name="bottom_attach">7</property>
                       </packing>
                     </child>
                     <child>
-                      <widget class="GtkEntry" id="testFileEdit">
+                      <widget class="GtkEntry" id="maskFileEdit">
                         <property name="visible">True</property>
                       </widget>
                       <packing>
                         <property name="left_attach">1</property>
                         <property name="right_attach">2</property>
-                        <property name="top_attach">6</property>
-                        <property name="bottom_attach">7</property>
+                        <property name="top_attach">9</property>
+                        <property name="bottom_attach">10</property>
                       </packing>
                     </child>
                     <child>
-                      <widget class="GtkLabel" id="testEditLabel">
+                      <widget class="GtkLabel" id="maskEditLabel">
                         <property name="visible">True</property>
                         <property name="xalign">0</property>
-                        <property name="label" translatable="yes">File name to use, if package.keywords is a directory: </property>
+                        <property name="label" translatable="yes">File name to use, if package.mask/package.unmask is a directory: </property>
                         <property name="single_line_mode">True</property>
                       </widget>
                       <packing>
-                        <property name="top_attach">6</property>
-                        <property name="bottom_attach">7</property>
+                        <property name="top_attach">9</property>
+                        <property name="bottom_attach">10</property>
                       </packing>
                     </child>
                     <child>
-                      <widget class="GtkCheckButton" id="testPerVersionCheck">
+                      <widget class="GtkCheckButton" id="maskPerVersionCheck">
                         <property name="visible">True</property>
-                        <property name="label" translatable="yes">Add only exact version to package.keywords</property>
+                        <property name="label" translatable="yes">Add only exact version to package.mask/package.unmask</property>
                         <property name="draw_indicator">True</property>
                       </widget>
                       <packing>
                         <property name="right_attach">2</property>
-                        <property name="top_attach">5</property>
-                        <property name="bottom_attach">6</property>
+                        <property name="top_attach">8</property>
+                        <property name="bottom_attach">9</property>
                       </packing>
                     </child>
                     <child>
-                      <widget class="GtkCheckButton" id="usePerVersionCheck">
+                      <widget class="GtkEventBox" id="hintEB">
                         <property name="visible">True</property>
-                        <property name="label" translatable="yes">Add only exact version to package.use</property>
-                        <property name="draw_indicator">True</property>
+                        <child>
+                          <widget class="GtkFrame" id="hintFrame">
+                            <property name="visible">True</property>
+                            <property name="label_xalign">0</property>
+                            <property name="shadow_type">GTK_SHADOW_OUT</property>
+                            <child>
+                              <widget class="GtkLabel" id="hintLabel">
+                                <property name="visible">True</property>
+                                <property name="xalign">0</property>
+                                <property name="label" translatable="yes">&lt;u&gt;You may use the following placeholders:&lt;/u&gt;
+
+																	&lt;i&gt;$(cat)&lt;/i&gt;: category
+																	&lt;i&gt;$(pkg)&lt;/i&gt;: package name
+																	&lt;i&gt;$(cat-1)/$(cat-2)&lt;/i&gt;: first/second part of the category</property>
+                                <property name="use_markup">True</property>
+                              </widget>
+                            </child>
+                            <child>
+                              <placeholder/>
+                              <packing>
+                                <property name="type">label_item</property>
+                              </packing>
+                            </child>
+                          </widget>
+                        </child>
                       </widget>
                       <packing>
                         <property name="right_attach">2</property>
-                        <property name="top_attach">2</property>
-                        <property name="bottom_attach">3</property>
                       </packing>
                     </child>
                     <child>
-                      <widget class="GtkLabel" id="useEditLabel">
+                      <widget class="GtkLabel" id="useLabel">
                         <property name="visible">True</property>
                         <property name="xalign">0</property>
-                        <property name="label" translatable="yes">File name to use, if package.use is a directory: </property>
+                        <property name="xpad">5</property>
+                        <property name="label" translatable="yes">&lt;u&gt;&lt;i&gt;Use-Flags&lt;/i&gt;&lt;/u&gt;</property>
+                        <property name="use_markup">True</property>
                         <property name="single_line_mode">True</property>
                       </widget>
                       <packing>
-                        <property name="top_attach">3</property>
-                        <property name="bottom_attach">4</property>
+                        <property name="top_attach">1</property>
+                        <property name="bottom_attach">2</property>
+                        <property name="y_padding">6</property>
                       </packing>
                     </child>
                     <child>
-                      <widget class="GtkEntry" id="useFileEdit">
+                      <widget class="GtkLabel" id="testLabel">
+                        <property name="visible">True</property>
+                        <property name="xalign">0</property>
+                        <property name="xpad">5</property>
+                        <property name="label" translatable="yes">&lt;u&gt;&lt;i&gt;Testing Keywords&lt;/i&gt;&lt;/u&gt;</property>
+                        <property name="use_markup">True</property>
+                        <property name="single_line_mode">True</property>
+                      </widget>
+                      <packing>
+                        <property name="top_attach">4</property>
+                        <property name="bottom_attach">5</property>
+                        <property name="y_padding">5</property>
+                      </packing>
+                    </child>
+                    <child>
+                      <widget class="GtkLabel" id="maskLabel">
                         <property name="visible">True</property>
+                        <property name="xalign">0</property>
+                        <property name="xpad">5</property>
+                        <property name="label" translatable="yes">&lt;u&gt;&lt;i&gt;Masking Keywords&lt;/i&gt;&lt;/u&gt;</property>
+                        <property name="use_markup">True</property>
+                        <property name="single_line_mode">True</property>
                       </widget>
                       <packing>
-                        <property name="left_attach">1</property>
-                        <property name="right_attach">2</property>
-                        <property name="top_attach">3</property>
-                        <property name="bottom_attach">4</property>
+                        <property name="top_attach">7</property>
+                        <property name="bottom_attach">8</property>
+                        <property name="y_padding">5</property>
                       </packing>
                     </child>
                   </widget>
@@ -1167,7 +1229,7 @@
             </child>
           </widget>
           <packing>
-            <property name="position">3</property>
+            <property name="position">4</property>
           </packing>
         </child>
         <child>
@@ -1196,7 +1258,7 @@
             </child>
           </widget>
           <packing>
-            <property name="position">4</property>
+            <property name="position">5</property>
           </packing>
         </child>
       </widget>
diff --git a/portato/gui/gtk/usetips.py b/portato/gui/gtk/usetips.py
index 6611e09..d59e397 100644
--- a/portato/gui/gtk/usetips.py
+++ b/portato/gui/gtk/usetips.py
@@ -10,7 +10,7 @@
 #
 # Written by René 'Necoro' Neumann <necoro@necoro.net>
 
-from portato.backend import Package
+from portato.backend import system
 from portato.backend.flags import invert_use_flag
 
 from TreeViewTooltips import TreeViewTooltips
@@ -48,7 +48,7 @@ class UseTips (TreeViewTooltips):
 			return None
 
 	def __get_flags(self, cpv):
-		pkg = Package(cpv)
+		pkg = system.new_package(cpv)
 		enabled = []
 		disabled = []
 
diff --git a/portato/gui/gtk/windows.py b/portato/gui/gtk/windows.py
index a872f3a..7841e5e 100644
--- a/portato/gui/gtk/windows.py
+++ b/portato/gui/gtk/windows.py
@@ -23,8 +23,7 @@ if USE_GTKSOURCEVIEW:
 # our backend stuff
 from portato.helper import *
 from portato.constants import CONFIG_LOCATION, VERSION, DATA_DIR
-from portato import backend
-from portato.backend import flags
+from portato.backend import flags, system
 from portato.backend.exceptions import *
 
 # more GUI stuff
@@ -37,7 +36,6 @@ from usetips import UseTips
 import vte
 
 # other
-from portage_util import unique_array
 import types
 
 GLADE_FILE = DATA_DIR+"portato.glade"
@@ -189,6 +187,19 @@ class PreferenceWindow (AbstractDialog):
 			"syncCommandEdit"	: "syncCmd_opt"
 			}
 
+	# mapping from the radio buttons to the system name
+	# widget name -> option
+	system_radios = {
+			"portageRadio" : "portage",
+			"pkgCoreRadio" : "pkgcore",
+			"paludisRadio" : "paludis"
+			}
+
+	# mapping from the system name to the radio button
+	# option -> widget name
+	systems = {}
+	systems.update(zip(system_radios.values(), system_radios.keys()))
+
 	def __init__ (self, parent, cfg):
 		"""Constructor.
 
@@ -206,6 +217,7 @@ class PreferenceWindow (AbstractDialog):
 		hintEB = self.tree.get_widget("hintEB")
 		hintEB.modify_bg(gtk.STATE_NORMAL, gtk.gdk.color_parse("#f3f785"))
 
+		# the checkboxes
 		for box in self.checkboxes:
 			val = self.checkboxes[box]
 			if type(val) == types.TupleType:
@@ -215,10 +227,14 @@ class PreferenceWindow (AbstractDialog):
 				self.tree.get_widget(box).\
 						set_active(self.cfg.get_boolean(val))
 
+		# the edits
 		for edit in self.edits:
 			self.tree.get_widget(edit).\
 					set_text(self.cfg.get(self.edits[edit]))
 
+		# the system radios
+		self.tree.get_widget(self.systems[self.cfg.get("system_opt").lower()]).set_active(True)
+
 		self.window.show_all()
 
 	def _save(self):
@@ -233,6 +249,10 @@ class PreferenceWindow (AbstractDialog):
 
 		for edit in self.edits:
 			self.cfg.set(self.edits[edit],self.tree.get_widget(edit).get_text())
+
+		for radio in self.system_radios:
+			if self.tree.get_widget(radio).get_active():
+				self.cfg.set("system_opt", self.system_radios[radio])
 					
 	def cb_ok_clicked(self, button):
 		"""Saves, writes to config-file and closes the window."""
@@ -355,8 +375,8 @@ class PackageTable:
 		self.instantChange = instantChange
 
 		# packages and installed packages
-		self.packages = backend.sort_package_list(backend.find_packages(cp, masked = True))
-		self.instPackages = backend.sort_package_list(backend.find_installed_packages(cp, masked = True))
+		self.packages = system.sort_package_list(system.find_packages(cp, masked = True))
+		self.instPackages = system.sort_package_list(system.find_installed_packages(cp, masked = True))
 
 		# version-combo-box
 		self.vCombo = self.build_vers_combo()
@@ -400,7 +420,7 @@ class PackageTable:
 		pkg_flags = pkg.get_all_use_flags()
 		pkg_flags.sort()
 		for use in pkg_flags:
-			store.append([pkg.is_use_flag_enabled(use), use, backend.get_use_desc(use, self.cp)])
+			store.append([pkg.is_use_flag_enabled(use), use, system.get_use_desc(use, self.cp)])
 		
 		return store
 
@@ -439,7 +459,7 @@ class PackageTable:
 			if self.version:
 				best_version = self.version
 			else:
-				best_version = backend.find_best_match(self.packages[0].get_cp(), (self.instPackages != [])).get_version()
+				best_version = system.find_best_match(self.packages[0].get_cp(), (self.instPackages != [])).get_version()
 			for i in range(len(self.packages)):
 				if self.packages[i].get_version() == best_version:
 					combo.set_active(i)
@@ -465,7 +485,7 @@ class PackageTable:
 			try:
 				try:
 					self.queue.append(self.actual_package().get_cpv(), unmerge = False, update = update)
-				except backend.PackageNotFoundException, e:
+				except PackageNotFoundException, e:
 					if unmask_dialog(e[0]) == gtk.RESPONSE_YES:
 						self.queue.append(self.actual_package().get_cpv(), unmerge = False, unmask = True, update = update)
 			except BlockedException, e:
@@ -473,7 +493,7 @@ class PackageTable:
 		else:
 			try:
 				self.queue.append(self.actual_package().get_cpv(), unmerge = True)
-			except backend.PackageNotFoundException, e:
+			except PackageNotFoundException, e:
 				masked_dialog(e[0])
 
 	def cb_combo_changed (self, combo):
@@ -730,7 +750,7 @@ class MainWindow (Window):
 		store = gtk.ListStore(str)
 
 		# build categories
-		for p in backend.list_categories():
+		for p in system.list_categories():
 			store.append([p])
 		# sort them alphabetically
 		store.set_sort_column_id(0, gtk.SORT_ASCENDING)
@@ -823,7 +843,7 @@ class MainWindow (Window):
 			iterator = store.get_original().get_iter(path)
 			if store.is_in_emerge(iterator):
 				package = store.get_value(iterator, 0)
-				cat, name, vers, rev = backend.split_package_name(package)
+				cat, name, vers, rev = system.split_cpv(package)
 				if rev != "r0": vers = vers+"-"+rev
 				self.show_package(cat+"/"+name, queue = self.queue, version = vers, instantChange = True, doEmerge = False)
 		return True
@@ -844,7 +864,7 @@ class MainWindow (Window):
 			changed_flags_dialog("masking keywords")
 			flags.write_masked()
 			flags.write_testing()
-			backend.reload_settings()
+			system.reload_settings()
 		
 		if not self.doUpdate:
 			self.queue.emerge(force=True)
@@ -861,11 +881,11 @@ class MainWindow (Window):
 
 	@Window.watch_cursor
 	def cb_update_clicked (self, action):
-		if not backend.am_i_root():
+		if not am_i_root():
 			not_root_dialog()
 		
 		else:
-			updating = backend.update_world(newuse = self.cfg.get_boolean("newuse_opt"), deep = self.cfg.get_boolean("deep_opt"))
+			updating = system.update_world(newuse = self.cfg.get_boolean("newuse_opt"), deep = self.cfg.get_boolean("deep_opt"))
 
 			debug("updating list:", [(x.get_cpv(), y.get_cpv()) for x,y in updating],"--> length:",len(updating))
 			try:
@@ -907,7 +927,7 @@ class MainWindow (Window):
 		return True
 
 	def cb_sync_clicked (self, action):
-		if not backend.am_i_root():
+		if not am_i_root():
 			not_root_dialog()
 		else:
 			self.notebook.set_current_page(self.CONSOLE_PAGE)
@@ -920,7 +940,7 @@ class MainWindow (Window):
 				self.queue.sync()
 
 	def cb_save_flags_clicked (self, action):
-		if not backend.am_i_root():
+		if not am_i_root():
 			not_root_dialog()
 		else:
 			flags.write_use_flags()
@@ -930,7 +950,7 @@ class MainWindow (Window):
 	@Window.watch_cursor
 	def cb_reload_clicked (self, action):
 		"""Reloads the portage settings and the database."""
-		backend.reload_settings()
+		system.reload_settings()
 		del self.db
 		self.db = Database()
 		self.db.populate()
@@ -939,7 +959,7 @@ class MainWindow (Window):
 	def cb_search_clicked (self, entry):
 		"""Do a search."""
 		if entry.get_text() != "":
-			packages = backend.find_all_packages(entry.get_text(), withVersion = False)
+			packages = system.find_all_packages(entry.get_text(), withVersion = False)
 
 			if packages == []:
 				nothing_found_dialog()
diff --git a/portato/gui/gui_helper.py b/portato/gui/gui_helper.py
index be42b52..cf03a57 100644
--- a/portato/gui/gui_helper.py
+++ b/portato/gui/gui_helper.py
@@ -12,7 +12,7 @@
 
 # some backend things
 from portato import backend
-from portato.backend import flags
+from portato.backend import flags, system
 from portato.helper import *
 
 # parser
@@ -45,7 +45,8 @@ class Config:
 			"deep_opt" : "deep",
 			"newuse_opt" : "newuse",
 			"syncCmd_opt" : "synccommand",
-			"useTips_opt" : "showusetips"
+			"useTips_opt" : "showusetips",
+			"system_opt" : "system"
 			}
 	
 	def __init__ (self, cfgFile):
@@ -205,8 +206,8 @@ class Database:
 		@type category: string"""
 		
 		# get the lists
-		packages = backend.find_all_packages(name = category, withVersion = False)
-		installed = backend.find_all_installed_packages(name = category, withVersion = False)
+		packages = system.find_all_packages(name = category, withVersion = False)
+		installed = system.find_all_installed_packages(name = category, withVersion = False)
 		
 		# cycle through packages
 		for p in packages:
@@ -294,17 +295,17 @@ class EmergeQueue:
 		@raises backend.PackageNotFoundException: If no package could be found - normally it is existing but masked."""
 
 		# for the beginning: let us create a package object - but it is not guaranteed, that it actually exists in portage
-		pkg = backend.Package(cpv)
+		pkg = system.new_package(cpv)
 		masked = not (pkg.is_masked() or pkg.is_testing(use_keywords=True)) # we are setting this to True in case we have unmasked it already, but portage does not know this
 		
 		# and now try to find it in portage
-		pkg = backend.find_packages("="+cpv, masked = masked)
+		pkg = system.find_packages("="+cpv, masked = masked)
 		
 		if pkg: # gotcha
 			pkg = pkg[0]
 
 		elif unmask: # no pkg returned, but we are allowed to unmask it
-			pkg = backend.find_packages("="+cpv, masked = True)[0]
+			pkg = system.find_packages("="+cpv, masked = True)[0]
 			if pkg.is_testing(use_keywords = True):
 				pkg.set_testing(True)
 			if pkg.is_masked():
@@ -338,7 +339,7 @@ class EmergeQueue:
 		try:
 			pkg = self._get_pkg_from_cpv(cpv, unmask)
 			if not pkg.is_installed():
-				old = backend.find_installed_packages(pkg.get_slot_cp())
+				old = system.find_installed_packages(pkg.get_slot_cp())
 				if old: 
 					old = old[0] # assume we have only one there; FIXME: slotted packages
 					update = True
@@ -450,11 +451,11 @@ class EmergeQueue:
 
 		for p in packages:
 			if p in ["world", "system"]: continue
-			cat = backend.split_package_name(p)[0] # get category
+			cat = system.split_cpv(p)[0] # get category
 			self.db.reload(cat)
 			debug("Category %s refreshed" % cat)
 
-	def _emerge (self, options, packages, it, command = ["/usr/bin/python","/usr/bin/emerge"]):
+	def _emerge (self, options, packages, it, command = None):
 		"""Calls emerge and updates the terminal.
 		
 		@param options: options to send to emerge
@@ -466,6 +467,9 @@ class EmergeQueue:
 		@param command: the command to execute - default is "/usr/bin/python /usr/bin/emerge"
 		@type command: string[]"""
 
+		if command is None:
+			command = system.get_merge_command()
+
 		# open tty
 		(master, slave) = pty.openpty()
 		self.console.set_pty(master)
@@ -501,8 +505,8 @@ class EmergeQueue:
 			# prepare package-list for oneshot
 			list, its = prepare(self.oneshotmerge)
 			
-			s = ["--oneshot"]
-			if not force: s += ["--verbose", "--pretend"]
+			s = system.get_oneshot_option()
+			if not force: s += system.get_pretend_option()
 			
 			self._emerge(s, list, its)
 		
@@ -512,7 +516,7 @@ class EmergeQueue:
 			list, its = prepare(self.mergequeue)
 
 			s = []
-			if not force: s = ["--verbose", "--pretend"]
+			if not force: s = system.get_pretend_option()
 		
 			self._emerge(s, list, its)
 
@@ -527,8 +531,8 @@ class EmergeQueue:
 		list = self.unmergequeue[:] # copy the unmerge-queue
 		
 		# set options
-		s = ["-C"]
-		if not force: s += ["-pv"]
+		s = system.get_unmerge_option()
+		if not force: s += system.get_pretend_option()
 		
 		self._emerge(s,list, [self.unmergeIt])
 
@@ -538,11 +542,11 @@ class EmergeQueue:
 		@param force: If False, '-pv' is send to emerge. Default: False.
 		@type force: boolean"""
 
-		options = ["--update"]
+		options = system.get_update_option()
 
-		if newuse: options += ["--newuse"]
-		if deep: options += ["--deep"]
-		if not force: options += ["-pv"]
+		if newuse: options += system.get_newuse_option()
+		if deep: options += system.get_deep_option()
+		if not force: options += system.get_pretend_option()
 
 		self._emerge(options, ["world"], [self.emergeIt])
 
@@ -552,10 +556,10 @@ class EmergeQueue:
 		@param command: command to execute to sync. If None "emerge --sync" is taken.
 		@type command: string[]"""
 
-		if command == None:
-			self._emerge(["--sync"], [], [])
-		else:
-			self._emerge([],[],[], command = command)
+		if command is None:
+			command = system.get_sync_command()
+		
+		self._emerge([],[],[], command = command)
 
 	def kill_emerge (self):
 		"""Kills the emerge process."""
diff --git a/portato/helper.py b/portato/helper.py
index fab8aa5..d66e256 100644
--- a/portato/helper.py
+++ b/portato/helper.py
@@ -3,7 +3,7 @@
 # File: portato/helper.py
 # This file is part of the Portato-Project, a graphical portage-frontend.
 #
-# Copyright (C) 2006 René 'Necoro' Neumann
+# Copyright (C) 2006-2007 René 'Necoro' Neumann
 # This is free software.  You may redistribute copies of it under the terms of
 # the GNU General Public License version 2.
 # There is NO WARRANTY, to the extent permitted by law.
@@ -66,3 +66,38 @@ def am_i_root ():
 		return True
 	else:
 		return False
+
+def unique_array(s):
+	"""Stolen from portage_utils:
+	lifted from python cookbook, credit: Tim Peters
+	Return a list of the elements in s in arbitrary order, sans duplicates"""
+	n = len(s)
+	# assume all elements are hashable, if so, it's linear
+	try:
+		return list(set(s))
+	except TypeError:
+		pass
+
+	# so much for linear.  abuse sort.
+	try:
+		t = list(s)
+		t.sort()
+	except TypeError:
+		pass
+	else:
+		assert n > 0
+		last = t[0]
+		lasti = i = 1
+		while i < n:
+			if t[i] != last:
+				t[lasti] = last = t[i]
+				lasti += 1
+			i += 1
+		return t[:lasti]
+
+	# blah.	 back to original portage.unique_array
+	u = []
+	for x in s:
+		if x not in u:
+			u.append(x)
+	return u
diff --git a/setup.py b/setup.py
index d48d396..737f2c9 100644
--- a/setup.py
+++ b/setup.py
@@ -4,7 +4,7 @@
 from distutils.core import setup, Extension
 from portato.constants import VERSION, DATA_DIR, FRONTENDS
 
-packages = ["portato", "portato.gui", "portato.backend"]
+packages = ["portato", "portato.gui", "portato.backend", "portato.backend.portage"]
 ext_modules = []
 data_files = []
 cmdclass = {}