Switch from tabs to 4 spaces

1 files changed, 617 insertions, 617 deletions

diff --git a/portato/gui/queue.py b/portato/gui/queue.py
index b5fb736..5ff600f 100644
--- a/portato/gui/queue.py
+++ b/portato/gui/queue.py
@@ -31,620 +31,620 @@ from .updater import Updater
 from .wrapper import GtkConsole, GtkTree
 
 class EmergeQueue:
-	"""This class manages the emerge queue."""
-	
-	def __init__ (self, tree = None, console = None, db = None, title_update = None, threadClass = threading.Thread):
-		"""Constructor.
-		
-		@param tree: Tree to append all the items to.
-		@type tree: GtkTree
-		@param console: Output is shown here.
-		@type console: GtkConsole
-		@param db: A database instance.
-		@type db: Database
-		@param title_update: A function, which will be called whenever there is a title update.
-		@type title_update: function(string)"""
-		
-		# the different queues
-		self.mergequeue = [] # for emerge
-		self.unmergequeue = [] # for emerge -C
-		self.oneshotmerge = [] # for emerge --oneshot
-		
-		# the emerge process
-		self.process = None
-		self.threadQueue = WaitingQueue(threadClass = threadClass)
-		self.pty = None
-
-		# dictionaries with data about the packages in the queue
-		self.iters = {"install" : {}, "uninstall" : {}, "update" : {}} # iterator in the tree
-		self.deps = {"install" : {}, "update" : {}} # all the deps of the package
-		self.blocks = {"install" : OrderedDict(), "update" : OrderedDict()}
-		
-		# member vars
-		self.tree = tree
-		if self.tree and not isinstance(self.tree, GtkTree): raise TypeError, "tree passed is not a GtkTree-object"
-		
-		self.console = console
-		if self.console and not isinstance(self.console, GtkConsole): raise TypeError, "console passed is not a GtkConsole-object"
-		
-		self.db = db
-		self.title_update = title_update
-		self.threadClass = threadClass
-		
-		if self.console:
-			self.pty = pty.openpty()
-			self.console.set_pty(self.pty[0])
-
-	def _get_pkg_from_cpv (self, cpv, unmask = False):
-		"""Gets a L{backend.Package}-object from a cpv.
-
-		@param cpv: the cpv to get the package for
-		@type cpv: string (cpv)
-		@param unmask: if True we will look for masked packages if we cannot find unmasked ones
-		@type unmask: boolean
-		@return: created package
-		@rtype: backend.Package
-		
-		@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 = 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 = 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 = system.find_packages("="+cpv, masked = True)
-
-			if not pkg:
-				raise backend.PackageNotFoundException(cpv) # also not found
-			else:
-				pkg = pkg[0]
-
-			if pkg.is_testing(use_keywords = True):
-				pkg.set_testing(True)
-			if pkg.is_masked():
-				pkg.set_masked()
-		
-		else: # no pkg returned - and we are not allowed to unmask
-			raise backend.PackageNotFoundException(cpv)
-		
-		return pkg
-	
-	def update_tree (self, it, cpv, unmask = False, oneshot = False, type = "install"):
-		"""This updates the tree recursivly, or? Isn't it? Bjorn!
-
-		@param it: iterator where to append
-		@type it: Iterator
-		@param cpv: The package to append.
-		@type cpv: string (cat/pkg-ver)
-		@param unmask: True if we are allowed to look for masked packages
-		@type unmask: boolean
-		@param oneshot: True if we want to emerge is oneshot
-		@type oneshot: boolean
-		@param type: the type of the updating
-		@type type: string
-		
-		@raises backend.BlockedException: When occured during dependency-calculation.
-		@raises backend.PackageNotFoundException: If no package could be found - normally it is existing but masked."""
-		
-		if cpv in self.deps[type]:
-			return # in list already and therefore it's already in the tree too	
-		
-		# try to find an already installed instance
-		update = False
-		downgrade = False
-		uVersion = None
-		changedUse = []
-		try:
-			pkg = self._get_pkg_from_cpv(cpv, unmask)
-			if not pkg.is_installed():
-				old = system.find_packages(pkg.get_slot_cp(), system.SET_INSTALLED)
-				if old: 
-					old = old[0] # assume we have only one there
-					cmp = pkg.compare_version(old)
-					if cmp > 0:
-						update = True
-					elif cmp < 0:
-						downgrade = True
-
-					uVersion = old.get_version()
-
-					old_iuse = set(old.get_iuse_flags())
-					new_iuse = set(pkg.get_iuse_flags())
-
-					for i in old_iuse.difference(new_iuse):
-						changedUse.append("-"+i)
-
-					for i in new_iuse.difference(old_iuse):
-						changedUse.append("+"+i)
-			else:
-				old_iuse = set(pkg.get_iuse_flags(installed = True))
-				new_iuse = set(pkg.get_iuse_flags(installed = False))
-
-				for i in old_iuse.difference(new_iuse):
-					changedUse.append("-"+i)
-
-				for i in new_iuse.difference(old_iuse):
-					changedUse.append("+"+i)
-
-		except backend.PackageNotFoundException, e: # package not found / package is masked -> delete current tree and re-raise the exception
-			if type == "update": # remove complete tree
-				self.remove_with_children(self.tree.first_iter(it), removeNewFlags = False)
-			
-			elif type == "install": # remove only the intentionally added package
-				top = self.tree.first_iter(it)
-				parent = self.tree.parent_iter(it)
-				
-				if parent:
-					while not self.tree.iter_equal(top, parent):
-						parent = self.tree.parent_iter(parent)
-						it = self.tree.parent_iter(it)
-
-					self.remove_with_children(it, removeNewFlags = False)
-
-				if not self.tree.iter_has_children(top): # remove completely if nothing left
-					self.remove(top)
-			raise
-
-		# add iter
-		subIt = self.tree.append(it, self.tree.build_append_value(cpv, oneshot = oneshot, update = update, downgrade = downgrade, version = uVersion, useChange = changedUse))
-		self.iters[type][cpv] = subIt
-		
-		# get dependencies
-		deps = pkg.get_dep_packages(return_blocks = True)
-		self.deps[type][cpv] = deps
-		
-		for d in deps:
-			if d[0] == "!": # block
-				dep = d[1:]
-				if not dep in self.blocks[type]:
-					self.blocks[type][dep] = set()
-
-				self.blocks[type][dep].add(cpv)
-			else: # recursive call
-				self.update_tree(subIt, d, unmask, type = type)
-		
-	def append (self, cpv, type = "install", update = False, forceUpdate = False, unmask = False, oneshot = False):
-		"""Appends a cpv either to the merge queue or to the unmerge-queue.
-		Also updates the tree-view.
-		
-		@param cpv: Package to add
-		@type cpv: string (cat/pkg-ver)
-		@param type: The type of this append process. Possible values are "install", "uninstall", "update".
-		@type type: string		
-		@param update: Set to True if a package is going to be updated (e.g. if the use-flags changed).
-		@type update: boolean
-		@param forceUpdate: Set to True if the update should be forced.
-		@type forceUpdate: boolean
-		@param unmask: True if we are allowed to look for masked packages
-		@type unmask: boolean
-		@param oneshot: True if this package should not be added to the world-file.
-		@type oneshot: boolean
-		
-		@raises portato.backend.PackageNotFoundException: if trying to add a package which does not exist"""
-		
-		if type in ("install", "update"): # emerge
-			if update:
-				pkg = self._get_pkg_from_cpv(cpv, unmask)
-				deps = pkg.get_dep_packages(return_blocks = True)
-				
-				if not forceUpdate and cpv in self.deps[type] and deps == self.deps[type][cpv]:
-					return # nothing changed - return
-				else:
-					hasBeenInQueue = (cpv in self.mergequeue or cpv in self.oneshotmerge)
-					parentIt = self.tree.parent_iter(self.iters[type][cpv])
-
-					# delete it out of the tree - but NOT the changed flags
-					self.remove_with_children(self.iters[type][cpv], removeNewFlags = False)
-					
-					if hasBeenInQueue: # package has been in queue before
-						self._queue_append(cpv, oneshot)
-					
-					self.update_tree(parentIt, cpv, unmask, oneshot = oneshot, type = type)
-			else: # not update
-				if type == "install":
-					if self.tree:
-						self.update_tree(self.tree.get_emerge_it(), cpv, unmask, type = type, oneshot = oneshot)
-					self._queue_append(cpv, oneshot)
-				elif type == "update" and self.tree:
-					self.update_tree(self.tree.get_update_it(), cpv, unmask, type = type, oneshot = oneshot)
-
-			# handle blocks
-			if self.blocks[type]:
-				# check whether anything blocks something in the queue
-				for block in self.blocks[type]:
-					for c in self.iters[type]:
-						if system.cpv_matches(c, block):
-							blocked = ", ".join(self.blocks[type][block]) 
-							warning("'%s' is blocked by: %s", c, blocked)
-							self.remove_with_children(self.iters[type][c], False)
-							raise BlockedException(c, blocked)
-
-				#
-				# check whether we block a version that we are going to replace nevertheless
-				#
-				
-				# get the blocks that block an installed package
-				inst = []
-				for block in self.blocks[type]:
-					pkgs = system.find_packages(block, system.SET_INSTALLED)
-					if pkgs:
-						inst.append((pkgs, block))
-
-				# the slot-cp's of the packages in the queue
-				slots = {}
-				for c in self.iters[type]:
-					slots[system.new_package(c).get_slot_cp()] = cpv
-
-				# check the installed blocks against the slot-cp's
-				for pkgs, block in inst[:]:
-					done = False
-					for pkg in pkgs:
-						done = False
-						if pkg.get_slot_cp() in slots:
-							debug("Block '%s' can be ignored, because the blocking package is going to be replaced with '%s'.", block, slots[pkg.get_slot_cp()])
-							done = True
-					if done:
-						inst.remove((pkgs,block))
-
-				if inst: # there is still something left to block
-					for pkgs, block in inst:
-						blocked = ", ".join(self.blocks[type][block])
-						warning("'%s' blocks the installation of: %s", pkgs[0].get_cpv(), blocked)
-						self.remove_with_children(self.iters[type][cpv], False)
-						raise BlockedException(blocked, pkgs[0].get_cpv())
-			
-		else: # unmerge
-			self.unmergequeue.append(cpv)
-			if self.tree: # update tree
-				self.iters["uninstall"].update({cpv: self.tree.append(self.tree.get_unmerge_it(), self.tree.build_append_value(cpv))})
-
-	def _queue_append (self, cpv, oneshot = False):
-		"""Convenience function appending a cpv either to self.mergequeue or to self.oneshotmerge.
-
-		@param cpv: cpv to add
-		@type cpv: string (cpv)
-		@param oneshot: True if this package should not be added to the world-file.
-		@type oneshot: boolean"""
-
-		if not oneshot:
-			if cpv not in self.mergequeue:
-				self.mergequeue.append(cpv)
-		else:
-			if cpv not in self.oneshotmerge:
-				self.oneshotmerge.append(cpv)
-
-	def doEmerge (self, options, packages, it, *args, **kwargs):
-		top = None
-		if self.tree and it:
-			for v in it.itervalues():
-				self.tree.set_in_progress(v)
-				top = self.tree.first_iter(v)
-				break
-
-		self.threadQueue.put(self.__emerge, options, packages, it, top, *args, **kwargs)
-	
-	def __emerge (self, options, packages, it, top, command = None):
-		"""Calls emerge and updates the terminal.
-		
-		@param options: options to send to emerge
-		@type options: string[]
-		@param packages: packages to emerge
-		@type packages: string[]
-		@param it: Iterators which point to these entries whose children will be removed after completion.
-		@type it: dict(string -> Iterator)
-		@param top: The top iterator
-		@type top: Iterator
-		@param command: the command to execute - default is "/usr/bin/python /usr/bin/emerge"
-		@type command: string[]"""
-
-		@plugin.hook("emerge", packages = packages, command = command, console = self.console, title_update = self.title_update)
-		def sub_emerge(command):
-			if command is None:
-				command = system.get_merge_command()
-
-			# open tty
-			if self.console:
-				self.console.reset()
-
-			def pre ():
-				os.setsid() # new session
-				if self.console:
-					import fcntl, termios
-					fcntl.ioctl(self.pty[1], termios.TIOCSCTTY, 0) # set pty-slave as session tty
-					os.dup2(self.pty[1], 0)
-					os.dup2(self.pty[1], 1)
-					os.dup2(self.pty[1], 2)
-
-			# get all categories that are being touched during the emerge process
-			cats = set(map(lambda x: x.split("/")[0], it.iterkeys()))
-
-			# start emerge
-			self.process = Popen(command+options+packages, shell = False, env = system.get_environment(), preexec_fn = pre)
-
-			# remove packages from queue
-			if self.tree and it and not self.tree.is_in_unmerge(top):
-				self.up = Updater(self, it, self.threadClass)
-			else:
-				self.up = None
-			
-			# update title
-			if self.console:
-				old_title = self.console.get_window_title()
-				while self.process and self.process.poll() is None:
-					if self.title_update : 
-						title = self.console.get_window_title()
-						if title != old_title:
-							self.title_update(title)
-							old_title = title
-						time.sleep(0.5)
-
-			if self.up: 
-				self.up.stop()
-				if it:
-					self.tree.set_in_progress(top, False)
-				else:
-					self.remove(top)
-			elif self.tree and it:
-				self.remove_with_children(top)
-
-			if self.title_update: self.title_update(None)
-
-			if self.process is None: # someone resetted this
-				self.threadQueue.next()
-				return
-			else:
-				ret = self.process.returncode
-				self.process = None
-				self.threadQueue.next()
-
-			@plugin.hook("after_emerge", packages = packages, retcode = ret)
-			def update_packages():
-				if self.db:
-					for cat in cats:
-						self.db.reload(cat)
-						debug("Category %s refreshed", cat)
-
-			update_packages()
-			
-		sub_emerge(command)
-
-	def emerge (self, force = False, options = None):
-		"""Emerges everything in the merge-queue.
-		
-		@param force: If False, '-pv' is send to emerge. Default: False.
-		@type force: boolean
-		@param options: Additional options to send to the emerge command
-		@type options: string[]"""
-		
-		def prepare(queue):
-			"""Prepares the list of iterators and the list of packages."""
-			list = []
-			its = {}
-			for k in queue:
-				list += ["="+k]
-				if self.tree: 
-					its.update({k : self.iters["install"][k]})
-
-			return list, its
-
-		if self.tree:
-			ownit = self.iters["install"]
-		else:
-			ownit = {}
-
-		# oneshot-queue
-		if self.oneshotmerge:
-			# prepare package-list for oneshot
-			list, its = prepare(self.oneshotmerge)
-			if not self.mergequeue :# the other one does not exist - remove completely
-				its = ownit
-			
-			s = system.get_oneshot_option()
-			if not force: s += system.get_pretend_option()
-			if options is not None: s += options
-			
-			self.doEmerge(s, list, its, caller = self.emerge)
-		
-		# normal queue
-		if self.mergequeue:
-			# prepare package-list
-			list, its = prepare(self.mergequeue)
-			if not self.oneshotmerge: # the other one does not exist - remove completely
-				its = ownit
-
-			s = []
-			if not force: s = system.get_pretend_option()
-			if options is not None: s += options
-		
-			self.doEmerge(s, list, its, caller = self.emerge)
-
-	def unmerge (self, force = False, options = None):
-		"""Unmerges everything in the umerge-queue.
-
-		@param force: If False, '-pv' is send to emerge. Default: False.
-		@type force: boolean
-		@param options: Additional options to send to the emerge command
-		@type options: string[]"""
-		
-		if len(self.unmergequeue) == 0: return # nothing in queue
-
-		list = self.unmergequeue[:] # copy the unmerge-queue
-		
-		# set options
-		s = system.get_unmerge_option()
-		if not force: s += system.get_pretend_option()
-		if options is not None: s += options
-		
-		if self.tree:
-			it = self.iters["uninstall"]
-		else:
-			it = {}
-
-		self.doEmerge(s,list, it, caller = self.unmerge)
-
-	def update_world(self, sets = ("world",), force = False, newuse = False, deep = False, options = None):
-		"""Does an update world. newuse and deep are the arguments handed to emerge.
-
-		@param sets: The sets to update.
-		@type sets: string[]
-		@param force: If False, '-pv' is send to emerge. Default: False.
-		@type force: boolean
-		@param newuse: If True, append newuse options
-		@type newuse: boolean
-		@param deep: If True, append deep options
-		@type deep: boolean
-		@param options: Additional options to send to the emerge command
-		@type options: string[]"""
-
-		opts = system.get_update_option()
-
-		if newuse: opts += system.get_newuse_option()
-		if deep: opts += system.get_deep_option()
-		if not force: opts += system.get_pretend_option()
-		if options is not None: opts += options
-
-		if self.tree:
-			it = self.iters["update"]
-		else:
-			it = {}
-
-		self.doEmerge(opts, list(sets), it, caller = self.update_world)
-
-	def sync (self, command = None):
-		"""Calls "emerge --sync".
-		
-		@param command: command to execute to sync. If None "emerge --sync" is taken.
-		@type command: string[]"""
-
-		if command is None:
-			command = system.get_sync_command()
-	
-		try:
-			while True:
-				idx = command.index("&&")
-				self.doEmerge([],[],{}, command[:idx], caller = self.sync)
-				command = command[idx+1:]
-		except ValueError: # no && in command
-			self.doEmerge([],[],{}, command, caller = self.sync)
-
-	def kill_emerge (self):
-		"""Kills the emerge process."""
-		if self.process is not None:
-			self.threadQueue.clear() # remove all pending emerge threads
-			try:
-				pgid = os.getpgid(self.process.pid)
-				os.killpg(pgid, signal.SIGTERM)
-				debug("Process should be terminated")
-				if self.process.poll() is None:
-					os.killpg(pgid, signal.SIGKILL)
-					debug("Process should be killed")
-			except AttributeError:
-				debug("AttributeError occured ==> process not exisiting - ignore")
-			except OSError:
-				debug("OSError occured ==> process already stopped - ignore")
-
-			self.process = None
-
-	def stop_emerge (self):
-		if self.process is not None:
-			os.killpg(os.getpgid(self.process.pid), signal.SIGSTOP)
-			debug("Process should be stopped")
-
-	def continue_emerge (self):
-		if self.process is not None:
-			os.killpg(os.getpgid(self.process.pid), signal.SIGCONT)
-			debug("Process should continue")
-
-	def remove_with_children (self, it, removeNewFlags = True):
-		"""Convenience function which removes all children of an iterator and than the iterator itself.
-
-		@param it: The iter which to remove.
-		@type it: Iterator
-		@param removeNewFlags: True if new flags should be removed; False otherwise. Default: True.
-		@type removeNewFlags: boolean"""
-
-		self.remove_children(it, removeNewFlags)
-		self.remove(it, removeNewFlags)
-
-	def remove_children (self, parentIt, removeNewFlags = True):
-		"""Removes all children of a given parent TreeIter recursivly.
-		
-		@param parentIt: The iter from which to remove all children.
-		@type parentIt: Iterator
-		@param removeNewFlags: True if new flags should be removed; False otherwise. Default: True.
-		@type removeNewFlags: boolean"""
-
-		childIt = self.tree.first_child_iter(parentIt)
-
-		while childIt:
-			if (self.tree.iter_has_children(childIt)): # recursive call
-				self.remove_children(childIt, removeNewFlags)
-			temp = childIt
-			childIt = self.tree.next_iter(childIt)
-			self.remove(temp, removeNewFlags)
-
-	def remove (self, it, removeNewFlags = True):
-		"""Removes a specific item in the tree. This does not remove the top-entries.
-		
-		@param it: Iterator which points to the entry we are going to remove.
-		@type it: Iterator
-		@param removeNewFlags: True if new flags should be removed; False otherwise. Default: True.
-		@type removeNewFlags: boolean"""
-
-		def __remove (type, cpv):
-			del self.iters[type][cpv]
-			try:
-				del self.deps[type][cpv]
-			except KeyError: # this seems to be removed due to a BlockedException - so no deps here atm ;)
-				debug("Catched KeyError => %s seems not to be in self.deps. Should be no harm in normal cases.", cpv)
-
-			for key in self.blocks[type].keys():
-				if cpv in self.blocks[type][key]:
-					self.blocks[type][key].remove(cpv)
-
-				if not self.blocks[type][key]: # list is empty -> remove the whole key
-					del self.blocks[type][key]
-			
-			if removeNewFlags: # remove the changed flags
-				flags.remove_new_use_flags(cpv)
-				flags.remove_new_masked(cpv)
-				flags.remove_new_testing(cpv)
-		
-		if self.tree.iter_has_parent(it):
-			cpv = self.tree.get_value(it, self.tree.get_cpv_column())
-			if self.tree.is_in_emerge(it): # Emerge
-				
-				__remove("install", cpv)
-
-				try:
-					self.mergequeue.remove(cpv)
-				except ValueError: # this is a dependency - ignore
-					try:
-						self.oneshotmerge.remove(cpv)
-					except ValueError:
-						debug("Catched ValueError => %s seems not to be in merge-queue. Should be no harm.", cpv)
-			
-			elif self.tree.is_in_unmerge(it): # in Unmerge
-				del self.iters["uninstall"][cpv]
-				self.unmergequeue.remove(cpv)
-			
-			elif self.tree.is_in_update(it):
-				__remove("update", cpv)
-
-			
-		self.tree.remove(it)
-
-	def is_empty (self):
-		"""Checks whether the current queue is empty and not working. Therefore it looks, whether the queues are empty,
-		and the process is not running.
-
-		@returns: True if everything is empty and the process is not running.
-		@rtype: bool"""
-
-		return not (self.process or any(map(len, self.iters.itervalues())))
+    """This class manages the emerge queue."""
+    
+    def __init__ (self, tree = None, console = None, db = None, title_update = None, threadClass = threading.Thread):
+        """Constructor.
+        
+        @param tree: Tree to append all the items to.
+        @type tree: GtkTree
+        @param console: Output is shown here.
+        @type console: GtkConsole
+        @param db: A database instance.
+        @type db: Database
+        @param title_update: A function, which will be called whenever there is a title update.
+        @type title_update: function(string)"""
+        
+        # the different queues
+        self.mergequeue = [] # for emerge
+        self.unmergequeue = [] # for emerge -C
+        self.oneshotmerge = [] # for emerge --oneshot
+        
+        # the emerge process
+        self.process = None
+        self.threadQueue = WaitingQueue(threadClass = threadClass)
+        self.pty = None
+
+        # dictionaries with data about the packages in the queue
+        self.iters = {"install" : {}, "uninstall" : {}, "update" : {}} # iterator in the tree
+        self.deps = {"install" : {}, "update" : {}} # all the deps of the package
+        self.blocks = {"install" : OrderedDict(), "update" : OrderedDict()}
+        
+        # member vars
+        self.tree = tree
+        if self.tree and not isinstance(self.tree, GtkTree): raise TypeError, "tree passed is not a GtkTree-object"
+        
+        self.console = console
+        if self.console and not isinstance(self.console, GtkConsole): raise TypeError, "console passed is not a GtkConsole-object"
+        
+        self.db = db
+        self.title_update = title_update
+        self.threadClass = threadClass
+        
+        if self.console:
+            self.pty = pty.openpty()
+            self.console.set_pty(self.pty[0])
+
+    def _get_pkg_from_cpv (self, cpv, unmask = False):
+        """Gets a L{backend.Package}-object from a cpv.
+
+        @param cpv: the cpv to get the package for
+        @type cpv: string (cpv)
+        @param unmask: if True we will look for masked packages if we cannot find unmasked ones
+        @type unmask: boolean
+        @return: created package
+        @rtype: backend.Package
+        
+        @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 = 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 = 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 = system.find_packages("="+cpv, masked = True)
+
+            if not pkg:
+                raise backend.PackageNotFoundException(cpv) # also not found
+            else:
+                pkg = pkg[0]
+
+            if pkg.is_testing(use_keywords = True):
+                pkg.set_testing(True)
+            if pkg.is_masked():
+                pkg.set_masked()
+        
+        else: # no pkg returned - and we are not allowed to unmask
+            raise backend.PackageNotFoundException(cpv)
+        
+        return pkg
+    
+    def update_tree (self, it, cpv, unmask = False, oneshot = False, type = "install"):
+        """This updates the tree recursivly, or? Isn't it? Bjorn!
+
+        @param it: iterator where to append
+        @type it: Iterator
+        @param cpv: The package to append.
+        @type cpv: string (cat/pkg-ver)
+        @param unmask: True if we are allowed to look for masked packages
+        @type unmask: boolean
+        @param oneshot: True if we want to emerge is oneshot
+        @type oneshot: boolean
+        @param type: the type of the updating
+        @type type: string
+        
+        @raises backend.BlockedException: When occured during dependency-calculation.
+        @raises backend.PackageNotFoundException: If no package could be found - normally it is existing but masked."""
+        
+        if cpv in self.deps[type]:
+            return # in list already and therefore it's already in the tree too    
+        
+        # try to find an already installed instance
+        update = False
+        downgrade = False
+        uVersion = None
+        changedUse = []
+        try:
+            pkg = self._get_pkg_from_cpv(cpv, unmask)
+            if not pkg.is_installed():
+                old = system.find_packages(pkg.get_slot_cp(), system.SET_INSTALLED)
+                if old: 
+                    old = old[0] # assume we have only one there
+                    cmp = pkg.compare_version(old)
+                    if cmp > 0:
+                        update = True
+                    elif cmp < 0:
+                        downgrade = True
+
+                    uVersion = old.get_version()
+
+                    old_iuse = set(old.get_iuse_flags())
+                    new_iuse = set(pkg.get_iuse_flags())
+
+                    for i in old_iuse.difference(new_iuse):
+                        changedUse.append("-"+i)
+
+                    for i in new_iuse.difference(old_iuse):
+                        changedUse.append("+"+i)
+            else:
+                old_iuse = set(pkg.get_iuse_flags(installed = True))
+                new_iuse = set(pkg.get_iuse_flags(installed = False))
+
+                for i in old_iuse.difference(new_iuse):
+                    changedUse.append("-"+i)
+
+                for i in new_iuse.difference(old_iuse):
+                    changedUse.append("+"+i)
+
+        except backend.PackageNotFoundException, e: # package not found / package is masked -> delete current tree and re-raise the exception
+            if type == "update": # remove complete tree
+                self.remove_with_children(self.tree.first_iter(it), removeNewFlags = False)
+            
+            elif type == "install": # remove only the intentionally added package
+                top = self.tree.first_iter(it)
+                parent = self.tree.parent_iter(it)
+                
+                if parent:
+                    while not self.tree.iter_equal(top, parent):
+                        parent = self.tree.parent_iter(parent)
+                        it = self.tree.parent_iter(it)
+
+                    self.remove_with_children(it, removeNewFlags = False)
+
+                if not self.tree.iter_has_children(top): # remove completely if nothing left
+                    self.remove(top)
+            raise
+
+        # add iter
+        subIt = self.tree.append(it, self.tree.build_append_value(cpv, oneshot = oneshot, update = update, downgrade = downgrade, version = uVersion, useChange = changedUse))
+        self.iters[type][cpv] = subIt
+        
+        # get dependencies
+        deps = pkg.get_dep_packages(return_blocks = True)
+        self.deps[type][cpv] = deps
+        
+        for d in deps:
+            if d[0] == "!": # block
+                dep = d[1:]
+                if not dep in self.blocks[type]:
+                    self.blocks[type][dep] = set()
+
+                self.blocks[type][dep].add(cpv)
+            else: # recursive call
+                self.update_tree(subIt, d, unmask, type = type)
+        
+    def append (self, cpv, type = "install", update = False, forceUpdate = False, unmask = False, oneshot = False):
+        """Appends a cpv either to the merge queue or to the unmerge-queue.
+        Also updates the tree-view.
+        
+        @param cpv: Package to add
+        @type cpv: string (cat/pkg-ver)
+        @param type: The type of this append process. Possible values are "install", "uninstall", "update".
+        @type type: string        
+        @param update: Set to True if a package is going to be updated (e.g. if the use-flags changed).
+        @type update: boolean
+        @param forceUpdate: Set to True if the update should be forced.
+        @type forceUpdate: boolean
+        @param unmask: True if we are allowed to look for masked packages
+        @type unmask: boolean
+        @param oneshot: True if this package should not be added to the world-file.
+        @type oneshot: boolean
+        
+        @raises portato.backend.PackageNotFoundException: if trying to add a package which does not exist"""
+        
+        if type in ("install", "update"): # emerge
+            if update:
+                pkg = self._get_pkg_from_cpv(cpv, unmask)
+                deps = pkg.get_dep_packages(return_blocks = True)
+                
+                if not forceUpdate and cpv in self.deps[type] and deps == self.deps[type][cpv]:
+                    return # nothing changed - return
+                else:
+                    hasBeenInQueue = (cpv in self.mergequeue or cpv in self.oneshotmerge)
+                    parentIt = self.tree.parent_iter(self.iters[type][cpv])
+
+                    # delete it out of the tree - but NOT the changed flags
+                    self.remove_with_children(self.iters[type][cpv], removeNewFlags = False)
+                    
+                    if hasBeenInQueue: # package has been in queue before
+                        self._queue_append(cpv, oneshot)
+                    
+                    self.update_tree(parentIt, cpv, unmask, oneshot = oneshot, type = type)
+            else: # not update
+                if type == "install":
+                    if self.tree:
+                        self.update_tree(self.tree.get_emerge_it(), cpv, unmask, type = type, oneshot = oneshot)
+                    self._queue_append(cpv, oneshot)
+                elif type == "update" and self.tree:
+                    self.update_tree(self.tree.get_update_it(), cpv, unmask, type = type, oneshot = oneshot)
+
+            # handle blocks
+            if self.blocks[type]:
+                # check whether anything blocks something in the queue
+                for block in self.blocks[type]:
+                    for c in self.iters[type]:
+                        if system.cpv_matches(c, block):
+                            blocked = ", ".join(self.blocks[type][block]) 
+                            warning("'%s' is blocked by: %s", c, blocked)
+                            self.remove_with_children(self.iters[type][c], False)
+                            raise BlockedException(c, blocked)
+
+                #
+                # check whether we block a version that we are going to replace nevertheless
+                #
+                
+                # get the blocks that block an installed package
+                inst = []
+                for block in self.blocks[type]:
+                    pkgs = system.find_packages(block, system.SET_INSTALLED)
+                    if pkgs:
+                        inst.append((pkgs, block))
+
+                # the slot-cp's of the packages in the queue
+                slots = {}
+                for c in self.iters[type]:
+                    slots[system.new_package(c).get_slot_cp()] = cpv
+
+                # check the installed blocks against the slot-cp's
+                for pkgs, block in inst[:]:
+                    done = False
+                    for pkg in pkgs:
+                        done = False
+                        if pkg.get_slot_cp() in slots:
+                            debug("Block '%s' can be ignored, because the blocking package is going to be replaced with '%s'.", block, slots[pkg.get_slot_cp()])
+                            done = True
+                    if done:
+                        inst.remove((pkgs,block))
+
+                if inst: # there is still something left to block
+                    for pkgs, block in inst:
+                        blocked = ", ".join(self.blocks[type][block])
+                        warning("'%s' blocks the installation of: %s", pkgs[0].get_cpv(), blocked)
+                        self.remove_with_children(self.iters[type][cpv], False)
+                        raise BlockedException(blocked, pkgs[0].get_cpv())
+            
+        else: # unmerge
+            self.unmergequeue.append(cpv)
+            if self.tree: # update tree
+                self.iters["uninstall"].update({cpv: self.tree.append(self.tree.get_unmerge_it(), self.tree.build_append_value(cpv))})
+
+    def _queue_append (self, cpv, oneshot = False):
+        """Convenience function appending a cpv either to self.mergequeue or to self.oneshotmerge.
+
+        @param cpv: cpv to add
+        @type cpv: string (cpv)
+        @param oneshot: True if this package should not be added to the world-file.
+        @type oneshot: boolean"""
+
+        if not oneshot:
+            if cpv not in self.mergequeue:
+                self.mergequeue.append(cpv)
+        else:
+            if cpv not in self.oneshotmerge:
+                self.oneshotmerge.append(cpv)
+
+    def doEmerge (self, options, packages, it, *args, **kwargs):
+        top = None
+        if self.tree and it:
+            for v in it.itervalues():
+                self.tree.set_in_progress(v)
+                top = self.tree.first_iter(v)
+                break
+
+        self.threadQueue.put(self.__emerge, options, packages, it, top, *args, **kwargs)
+    
+    def __emerge (self, options, packages, it, top, command = None):
+        """Calls emerge and updates the terminal.
+        
+        @param options: options to send to emerge
+        @type options: string[]
+        @param packages: packages to emerge
+        @type packages: string[]
+        @param it: Iterators which point to these entries whose children will be removed after completion.
+        @type it: dict(string -> Iterator)
+        @param top: The top iterator
+        @type top: Iterator
+        @param command: the command to execute - default is "/usr/bin/python /usr/bin/emerge"
+        @type command: string[]"""
+
+        @plugin.hook("emerge", packages = packages, command = command, console = self.console, title_update = self.title_update)
+        def sub_emerge(command):
+            if command is None:
+                command = system.get_merge_command()
+
+            # open tty
+            if self.console:
+                self.console.reset()
+
+            def pre ():
+                os.setsid() # new session
+                if self.console:
+                    import fcntl, termios
+                    fcntl.ioctl(self.pty[1], termios.TIOCSCTTY, 0) # set pty-slave as session tty
+                    os.dup2(self.pty[1], 0)
+                    os.dup2(self.pty[1], 1)
+                    os.dup2(self.pty[1], 2)
+
+            # get all categories that are being touched during the emerge process
+            cats = set(map(lambda x: x.split("/")[0], it.iterkeys()))
+
+            # start emerge
+            self.process = Popen(command+options+packages, shell = False, env = system.get_environment(), preexec_fn = pre)
+
+            # remove packages from queue
+            if self.tree and it and not self.tree.is_in_unmerge(top):
+                self.up = Updater(self, it, self.threadClass)
+            else:
+                self.up = None
+            
+            # update title
+            if self.console:
+                old_title = self.