/usr/share/pyshared/liblarch/tree.py is in python-liblarch 2.1.0-2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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# -----------------------------------------------------------------------------
# Liblarch - a library to handle directed acyclic graphs
# Copyright (c) 2011-2012 - Lionel Dricot & Izidor MatuĊĦov
#
# This program is free software: you can redistribute it and/or modify it under
# the terms of the GNU Lesser General Public License as published by the Free
# Software Foundation, either version 3 of the License, or (at your option) any
# later version.
#
# This program is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
# FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
# details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
# -----------------------------------------------------------------------------
import processqueue
from liblarch.treenode import _Node
class MainTree:
""" Tree which stores and handle all requests """
def __init__(self):
""" Initialize MainTree.
@param root - the "root" node which contains all nodes
"""
self.nodes = {}
self.pending_relationships = []
self.__cllbcks = {}
self.root_id = 'root'
self.root = _Node(self.root_id)
_Node._set_tree(self.root,self)
self._queue = processqueue.SyncQueue()
def __str__(self):
return "<Tree: root = '%s'>" % self.root
def get_root(self):
""" Return root node """
return self.root
####### INTERFACE FOR CALLBACKS ###############################################
def register_callback(self, event, func):
""" Store function and return unique key which can be used to
unregister the callback later """
if not self.__cllbcks.has_key(event):
self.__cllbcks[event] = {}
callbacks = self.__cllbcks[event]
key = 0
while callbacks.has_key(key):
key += 1
callbacks[key] = func
return key
def deregister_callback(self, event, key):
""" Remove the callback identifed by key (from register_cllbck) """
try:
del self.__cllbcks[event][key]
except KeyError:
pass
def _callback(self, event, node_id):
""" Inform others about the event """
#We copy the dict to not loop on it while it could be modified
dic = dict(self.__cllbcks.get(event, {}))
for func in dic.itervalues():
func(node_id)
####### INTERFACE FOR HANDLING REQUESTS #######################################
def add_node(self, node, parent_id=None, priority="low"):
self._queue.push(self._add_node, node, parent_id, priority=priority)
def remove_node(self, node_id, recursive=False):
self._queue.push(self._remove_node, node_id, recursive)
def modify_node(self, node_id, priority="low"):
self._queue.push(self._modify_node, node_id, priority=priority)
def new_relationship(self, parent_id, child_id):
self._queue.push(self._new_relationship, parent_id, child_id)
def break_relationship(self, parent_id, child_id):
self._queue.push(self._break_relationship, parent_id, child_id)
def refresh_all(self):
""" Refresh all nodes """
for node_id in self.nodes.keys():
self.modify_node(node_id)
####### IMPLEMENTATION OF HANDLING REQUESTS ###################################
def _create_relationship(self, parent_id, child_id):
""" Create relationship without any checks """
parent = self.nodes[parent_id]
child = self.nodes[child_id]
if child_id not in parent.children:
parent.children.append(child_id)
if parent_id not in child.parents:
child.parents.append(parent_id)
if child_id in self.root.children:
self.root.children.remove(child_id)
def _destroy_relationship(self, parent_id, child_id):
""" Destroy relationship without any checks """
parent = self.nodes[parent_id]
child = self.nodes[child_id]
if child_id in parent.children:
parent.children.remove(child_id)
if parent_id in child.parents:
child.parents.remove(parent_id)
def _is_circular_relation(self, parent_id, child_id):
""" Would the new relation be circular?
Go over every possible ancestors. If one of them is child_id,
this would be circular relation.
"""
visited = []
ancestors = [parent_id]
while ancestors != []:
node_id = ancestors.pop(0)
if node_id == child_id:
return True
if node_id not in self.nodes:
continue
for ancestor_id in self.nodes[node_id].parents:
if ancestor_id not in visited:
ancestors.append(ancestor_id)
return False
def _add_node(self, node, parent_id):
""" Add a node to the tree
@param node - node to be added
@param parent_id - parent to add or it will be add to root
"""
node_id = node.get_id()
if node_id in self.nodes:
print "Error: Node '%s' already exists" % node_id
return False
_Node._set_tree(node,self)
for relationship in node.pending_relationships:
if relationship not in self.pending_relationships:
self.pending_relationships.append(relationship)
node.pending_relationships = []
self.nodes[node_id] = node
add_to_root = True
parents_to_refresh = []
children_to_refresh = []
# Build pending relationships
for rel_parent_id, rel_child_id in list(self.pending_relationships):
# Adding as a child
if rel_child_id == node_id and rel_parent_id in self.nodes:
if not self._is_circular_relation(rel_parent_id, node_id):
self._create_relationship(rel_parent_id, node_id)
add_to_root = False
parents_to_refresh.append(rel_parent_id)
else:
print "Error: Detected pending circular relationship", \
rel_parent_id, rel_child_id
self.pending_relationships.remove((rel_parent_id, rel_child_id))
# Adding as a parent
if rel_parent_id == node_id and rel_child_id in self.nodes:
if not self._is_circular_relation(node_id, rel_child_id):
self._create_relationship(node_id, rel_child_id)
children_to_refresh.append(rel_child_id)
else:
print "Error: Detected pending circular relationship", \
rel_parent_id, rel_child_id
self.pending_relationships.remove((rel_parent_id, rel_child_id))
# Build relationship with given parent
if parent_id is not None:
if self._is_circular_relation(parent_id, node_id):
raise Exception('Creating circular relationship between %s and %s' % \
(parent_id, node_id))
if parent_id in self.nodes:
self._create_relationship(parent_id, node_id)
add_to_root = False
parents_to_refresh.append(parent_id)
else:
self.pending_relationships.append((parent_id, node_id))
# Add at least to root
if add_to_root:
self.root.children.append(node_id)
# Send callbacks
#updating the parent and the children is handled by the FT
self._callback("node-added", node_id)
# #The following callback is only needed in case we have a
# #Flat filter applied.
# for parent_id in parents_to_refresh:
# self._callback("node-modified", parent_id)
#this callback is really fast. No problem
# for child_id in children_to_refresh:
# #FIXME: why parent_id? this should be a bug!
# #removing this doesn't affect the tests. Why is it useful?
# self._callback("node-modified", child_id)
def _remove_node(self, node_id, recursive=False):
""" Remove node from tree """
if node_id not in self.nodes:
print "*** Warning *** Trying to remove a non-existing node"
return
# Do not remove root node
if node_id is None:
return
# Remove pending relationships with this node
for relation in list(self.pending_relationships):
if node_id in relation:
self.pending_relationships.remove(relation)
node = self.nodes[node_id]
# Handle parents
for parent_id in node.parents:
self._destroy_relationship(parent_id, node_id)
self._callback('node-modified', parent_id)
# Handle children
for child_id in list(node.children):
if recursive:
self._remove_node(child_id, True)
else:
self._destroy_relationship(node_id, child_id)
self._callback('node-modified', child_id)
if self.nodes[child_id].parents == []:
self.root.children.append(child_id)
if node_id in self.root.children:
self.root.children.remove(node_id)
self.nodes.pop(node_id)
self._callback('node-deleted', node_id)
def _modify_node(self, node_id):
""" Force update of a node """
if node_id != self.root_id and node_id in self.nodes:
self._callback('node-modified', node_id)
def _new_relationship(self, parent_id, child_id):
""" Creates a new relationship
This method is used mainly from TreeNode"""
if (parent_id, child_id) in self.pending_relationships:
self.pending_relationships.remove((parent_id, child_id))
if not parent_id or not child_id or parent_id == child_id:
return False
if parent_id not in self.nodes or child_id not in self.nodes:
self.pending_relationships.append((parent_id, child_id))
return True
if self._is_circular_relation(parent_id, child_id):
self._destroy_relationship(parent_id, child_id)
raise Exception('Cannot build circular relationship between %s and %s' % (parent_id, child_id))
self._create_relationship(parent_id, child_id)
# Remove from root when having a new relationship
if child_id in self.root.children:
self.root.children.remove(child_id)
self._callback('node-modified', parent_id)
self._callback('node-modified', child_id)
def _break_relationship(self, parent_id, child_id):
""" Remove a relationship
This method is used mainly from TreeNode """
for rel_parent, rel_child in list(self.pending_relationships):
if rel_parent == parent_id and rel_child == child_id:
self.pending_relationships.remove((rel_parent, rel_child))
if not parent_id or not child_id or parent_id == child_id:
return False
if parent_id not in self.nodes or child_id not in self.nodes:
return False
self._destroy_relationship(parent_id, child_id)
# Move to root if beak the last parent
if self.nodes[child_id].get_parents() == []:
self.root.add_child(child_id)
self._callback('node-modified', parent_id)
self._callback('node-modified', child_id)
####### INTERFACE FOR READING STATE OF TREE ###################################
def has_node(self, node_id):
""" Is this node_id in this tree? """
return node_id in self.nodes
def get_node(self, node_id=None):
""" Return node of tree or root node of this tree """
if node_id in self.nodes:
return self.nodes[node_id]
elif node_id == self.root_id or node_id is None:
return self.root
else:
raise ValueError("Node %s is not in the tree" % node_id)
def get_node_for_path(self, path):
""" Convert path into node_id
@return node_id if path is valid, None otherwise
"""
if not path or path == ():
return None
node_id = path[-1]
if path in self.get_paths_for_node(node_id):
return node_id
else:
return None
return node_id
def get_paths_for_node(self, node_id):
""" Get all paths for node_id """
if not node_id or node_id == self.root_id:
return [()]
elif node_id in self.nodes:
node = self.nodes[node_id]
if node.has_parent():
paths = []
for parent_id in node.get_parents():
if parent_id not in self.nodes:
continue
for path in self.get_paths_for_node(parent_id):
paths.append(path + (node_id,))
return paths
else:
return [(node_id,)]
else:
raise ValueError("Cannot get path for non existing node %s" % node_id)
def get_all_nodes(self):
""" Return list of all nodes in this tree """
return self.nodes.keys()
def next_node(self, node_id, parent_id=None):
""" Return the next sibling node or None if there is none
@param node_id - we look for siblings of this node
@param parent_id - specify which siblings should be used,
if task has more parents. If None, random parent will be used
"""
if node_id is None:
raise ValueError('node_id should be different than None')
node = self.get_node(node_id)
parents_id = node.get_parents()
if len(parents_id) == 0:
parid = self.root_id
elif parent_id in parents_id:
parid = parent_id
else:
parid = parents_id[0]
parent = self.get_node(parid)
if not parent:
raise ValueError('Parent does not exist')
index = parent.get_child_index(node_id)
if index == None:
error = 'children are : %s\n' %parent.get_children()
error += 'node %s is not a child of %s' %(node_id,parid)
raise IndexError(error)
if parent.get_n_children() > index+1:
return parent.get_nth_child(index+1)
else:
return None
def print_tree(self, string=False):
output = self.root_id + "\n"
stack = [(" ", child_id) for child_id in reversed(self.root.children)]
while stack != []:
prefix, node_id = stack.pop()
output += prefix + node_id + "\n"
prefix += " "
for child_id in reversed(self.nodes[node_id].get_children()):
stack.append((prefix, child_id))
if string:
return output
else:
print output,
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