def _manage_space(self, size, target, tree_id):
"""
Manages spaces in the tree identified by ``tree_id`` by changing
the values of the left and right columns by ``size`` after the
given ``target`` point.
"""
if self.tree_model._mptt_is_tracking:
self.tree_model._mptt_track_tree_modified(tree_id)
else:
connection = self._get_connection()
qn = connection.ops.quote_name
opts = self.model._meta
root_ordering = self.model._mptt_meta.root_node_ordering
space_query = """
UPDATE %(table)s
SET %(left)s = CASE
WHEN %(left)s > %%s
THEN %(left)s + %%s
ELSE %(left)s END,
%(right)s = CASE
WHEN %(right)s > %%s
THEN %(right)s + %%s
ELSE %(right)s END
WHERE %(tree_id)s = %%s
AND (%(left)s > %%s OR %(right)s > %%s)""" % {
'table': qn(self.tree_model._meta.db_table),
'left': qn(opts.get_field(self.left_attr).column),
'right': qn(opts.get_field(self.right_attr).column),
'tree_id': qn(opts.get_field(self.tree_id_attr).column),
}
cursor = connection.cursor()
cursor.execute(space_query, [target, size, target, size,
clean_tree_ids(tree_id, root_ordering=root_ordering, vendor=connection.vendor),
target, target])
def _inter_tree_move_and_close_gap(self, node, level_change,
left_right_change, new_tree_id):
"""
Removes ``node`` from its current tree, with the given set of
changes being applied to ``node`` and its descendants, closing
the gap left by moving ``node`` as it does so.
"""
connection = self._get_connection(instance=node)
qn = connection.ops.quote_name
opts = self.model._meta
root_ordering = self.model._mptt_meta.root_node_ordering
inter_tree_move_query = """
UPDATE %(table)s
SET %(level)s = CASE
WHEN %(left)s >= %%s AND %(left)s <= %%s
THEN %(level)s - %%s
ELSE %(level)s END,
%(tree_id)s = CASE
WHEN %(left)s >= %%s AND %(left)s <= %%s
THEN %%s
ELSE %(tree_id)s END,
%(left)s = CASE
WHEN %(left)s >= %%s AND %(left)s <= %%s
THEN %(left)s - %%s
WHEN %(left)s > %%s
THEN %(left)s - %%s
ELSE %(left)s END,
%(right)s = CASE
WHEN %(right)s >= %%s AND %(right)s <= %%s
THEN %(right)s - %%s
WHEN %(right)s > %%s
THEN %(right)s - %%s
ELSE %(right)s END
WHERE %(tree_id)s = %%s""" % {
'table': qn(self.tree_model._meta.db_table),
'level': qn(opts.get_field(self.level_attr).column),
'left': qn(opts.get_field(self.left_attr).column),
'tree_id': qn(opts.get_field(self.tree_id_attr).column),
'right': qn(opts.get_field(self.right_attr).column),
}
left = getattr(node, self.left_attr)
right = getattr(node, self.right_attr)
gap_size = right - left + 1
gap_target_left = left - 1
new_tree_id, current_tree_id = clean_tree_ids(
new_tree_id,
getattr(node, self.tree_id_attr),
root_ordering=root_ordering,
vendor=connection.vendor)
params = [
left, right, level_change, left, right, new_tree_id, left, right,
left_right_change, gap_target_left, gap_size, left, right,
left_right_change, gap_target_left, gap_size, current_tree_id
]
cursor = connection.cursor()
cursor.execute(inter_tree_move_query, params)
def _make_sibling_of_root_node(self, node, target, position):
"""
Moves ``node``, making it a sibling of the given ``target`` root
node as specified by ``position``.
``node`` will be modified to reflect its new tree state in the
database.
Since we use tree ids to reduce the number of rows affected by
tree mangement during insertion and deletion, root nodes are not
true siblings; thus, making an item a sibling of a root node is
a special case which involves shuffling tree ids around.
"""
if node == target:
raise InvalidMove(_('A node may not be made a sibling of itself.'))
opts = self.model._meta
root_ordering = self.model._mptt_meta.root_node_ordering
tree_id = getattr(node, self.tree_id_attr)
target_tree_id = getattr(target, self.tree_id_attr)
if node.is_child_node():
if position == 'left':
space_target = target_tree_id - 1
new_tree_id = target_tree_id
elif position == 'right':
space_target = target_tree_id
new_tree_id = target_tree_id + 1
else:
raise ValueError(
_('An invalid position was given: %s.') % position)
self._create_tree_space(space_target)
if tree_id > space_target:
# The node's tree id has been incremented in the
# database - this change must be reflected in the node
# object for the method call below to operate on the
# correct tree.
setattr(node, self.tree_id_attr, tree_id + 1)
self._make_child_root_node(node, new_tree_id)
else:
if position == 'left':
if target_tree_id > tree_id:
left_sibling = target.get_previous_sibling()
if node == left_sibling:
return
new_tree_id = getattr(left_sibling, self.tree_id_attr)
lower_bound, upper_bound = tree_id, new_tree_id
shift = -1
else:
new_tree_id = target_tree_id
lower_bound, upper_bound = new_tree_id, tree_id
shift = 1
elif position == 'right':
if target_tree_id > tree_id:
new_tree_id = target_tree_id
lower_bound, upper_bound = tree_id, target_tree_id
shift = -1
else:
right_sibling = target.get_next_sibling()
if node == right_sibling:
return
new_tree_id = getattr(right_sibling, self.tree_id_attr)
lower_bound, upper_bound = new_tree_id, tree_id
shift = 1
else:
raise ValueError(
_('An invalid position was given: %s.') % position)
connection = self._get_connection(instance=node)
qn = connection.ops.quote_name
root_sibling_query = """
UPDATE %(table)s
SET %(tree_id)s = CASE
WHEN %(tree_id)s = %%s
THEN %%s
ELSE %(tree_id)s + %%s END
WHERE %(tree_id)s >= %%s AND %(tree_id)s <= %%s""" % {
'table': qn(self.tree_model._meta.db_table),
'tree_id': qn(opts.get_field(self.tree_id_attr).column),
}
cleaned_tree_id, cleaned_new_tree_id = clean_tree_ids(
tree_id,
new_tree_id,
root_ordering=root_ordering,
vendor=connection.vendor)
cursor = connection.cursor()
cursor.execute(root_sibling_query, [
cleaned_tree_id, cleaned_new_tree_id, shift, lower_bound,
upper_bound
])
setattr(node, self.tree_id_attr, new_tree_id)
def _move_root_node(self, node, target, position):
"""
Moves root node``node`` to a different tree, inserting it
relative to the given ``target`` node as specified by
``position``.
``node`` will be modified to reflect its new tree state in the
database.
"""
left = getattr(node, self.left_attr)
right = getattr(node, self.right_attr)
level = getattr(node, self.level_attr)
tree_id = getattr(node, self.tree_id_attr)
new_tree_id = getattr(target, self.tree_id_attr)
width = right - left + 1
if node == target:
raise InvalidMove(_('A node may not be made a child of itself.'))
elif tree_id == new_tree_id:
raise InvalidMove(
_('A node may not be made a child of any of its descendants.'))
space_target, level_change, left_right_change, parent, right_shift = \
self._calculate_inter_tree_move_values(node, target, position)
# Create space for the tree which will be inserted
self._create_space(width, space_target, new_tree_id)
# Move the root node, making it a child node
connection = self._get_connection(instance=node)
qn = connection.ops.quote_name
opts = self.model._meta
root_ordering = self.model._mptt_meta.root_node_ordering
move_tree_query = """
UPDATE %(table)s
SET %(level)s = %(level)s - %%s,
%(left)s = %(left)s - %%s,
%(right)s = %(right)s - %%s,
%(tree_id)s = %%s
WHERE %(left)s >= %%s AND %(left)s <= %%s
AND %(tree_id)s = %%s""" % {
'table': qn(self.tree_model._meta.db_table),
'level': qn(opts.get_field(self.level_attr).column),
'left': qn(opts.get_field(self.left_attr).column),
'right': qn(opts.get_field(self.right_attr).column),
'tree_id': qn(opts.get_field(self.tree_id_attr).column),
}
cleaned_tree_id, cleaned_new_tree_id = \
clean_tree_ids(tree_id, new_tree_id, root_ordering=root_ordering, vendor=connection.vendor)
cursor = connection.cursor()
cursor.execute(move_tree_query, [
level_change, left_right_change, left_right_change,
cleaned_new_tree_id, left, right, cleaned_tree_id
])
# Update the former root node to be consistent with the updated
# tree in the database.
setattr(node, self.left_attr, left - left_right_change)
setattr(node, self.right_attr, right - left_right_change)
setattr(node, self.level_attr, level - level_change)
setattr(node, self.tree_id_attr, new_tree_id)
setattr(node, self.parent_attr, parent)
node._mptt_cached_fields[self.parent_attr] = parent.pk
def _move_child_within_tree(self, node, target, position):
"""
Moves child node ``node`` within its current tree relative to
the given ``target`` node as specified by ``position``.
``node`` will be modified to reflect its new tree state in the
database.
"""
left = getattr(node, self.left_attr)
right = getattr(node, self.right_attr)
level = getattr(node, self.level_attr)
width = right - left + 1
tree_id = getattr(node, self.tree_id_attr)
target_left = getattr(target, self.left_attr)
target_right = getattr(target, self.right_attr)
target_level = getattr(target, self.level_attr)
if position == 'last-child' or position == 'first-child':
if node == target:
raise InvalidMove(
_('A node may not be made a child of itself.'))
elif left < target_left < right:
raise InvalidMove(
_('A node may not be made a child of any of its descendants.'
))
if position == 'last-child':
if target_right > right:
new_left = target_right - width
new_right = target_right - 1
else:
new_left = target_right
new_right = target_right + width - 1
else:
if target_left > left:
new_left = target_left - width + 1
new_right = target_left
else:
new_left = target_left + 1
new_right = target_left + width
level_change = level - target_level - 1
parent = target
elif position == 'left' or position == 'right':
if node == target:
raise InvalidMove(
_('A node may not be made a sibling of itself.'))
elif left < target_left < right:
raise InvalidMove(
_('A node may not be made a sibling of any of its descendants.'
))
if position == 'left':
if target_left > left:
new_left = target_left - width
new_right = target_left - 1
else:
new_left = target_left
new_right = target_left + width - 1
else:
if target_right > right:
new_left = target_right - width + 1
new_right = target_right
else:
new_left = target_right + 1
new_right = target_right + width
level_change = level - target_level
parent = getattr(target, self.parent_attr)
else:
raise ValueError(
_('An invalid position was given: %s.') % position)
left_boundary = min(left, new_left)
right_boundary = max(right, new_right)
left_right_change = new_left - left
gap_size = width
if left_right_change > 0:
gap_size = -gap_size
connection = self._get_connection(instance=node)
qn = connection.ops.quote_name
opts = self.model._meta
root_ordering = self.model._mptt_meta.root_node_ordering
# The level update must come before the left update to keep
# MySQL happy - left seems to refer to the updated value
# immediately after its update has been specified in the query
# with MySQL, but not with SQLite or Postgres.
move_subtree_query = """
UPDATE %(table)s
SET %(level)s = CASE
WHEN %(left)s >= %%s AND %(left)s <= %%s
THEN %(level)s - %%s
ELSE %(level)s END,
%(left)s = CASE
WHEN %(left)s >= %%s AND %(left)s <= %%s
THEN %(left)s + %%s
WHEN %(left)s >= %%s AND %(left)s <= %%s
THEN %(left)s + %%s
ELSE %(left)s END,
%(right)s = CASE
WHEN %(right)s >= %%s AND %(right)s <= %%s
THEN %(right)s + %%s
WHEN %(right)s >= %%s AND %(right)s <= %%s
THEN %(right)s + %%s
ELSE %(right)s END
WHERE %(tree_id)s = %%s""" % {
'table': qn(self.tree_model._meta.db_table),
'level': qn(opts.get_field(self.level_attr).column),
'left': qn(opts.get_field(self.left_attr).column),
'right': qn(opts.get_field(self.right_attr).column),
'tree_id': qn(opts.get_field(self.tree_id_attr).column),
}
cursor = connection.cursor()
cursor.execute(move_subtree_query, [
left, right, level_change, left, right, left_right_change,
left_boundary, right_boundary, gap_size, left, right,
left_right_change, left_boundary, right_boundary, gap_size,
clean_tree_ids(
tree_id, root_ordering=root_ordering, vendor=connection.vendor)
])
# Update the node to be consistent with the updated
# tree in the database.
setattr(node, self.left_attr, new_left)
setattr(node, self.right_attr, new_right)
setattr(node, self.level_attr, level - level_change)
setattr(node, self.parent_attr, parent)
node._mptt_cached_fields[self.parent_attr] = parent.pk