# Example: <tt>acts_as_nested_set :counter_cache => :children_count</tt>
#
# See CollectiveIdea::Acts::NestedSet::Model::ClassMethods for a list of class methods and
- # CollectiveIdea::Acts::NestedSet::Model::InstanceMethods for a list of instance methods added
+ # CollectiveIdea::Acts::NestedSet::Model for a list of instance methods added
# to acts_as_nested_set models
def acts_as_nested_set(options = {})
options = {
#
# category.self_and_descendants.count
# category.ancestors.find(:all, :conditions => "name like '%foo%'")
- module InstanceMethods
- # Value of the parent column
- def parent_id
- self[parent_column_name]
- end
- # Value of the left column
- def left
- self[left_column_name]
- end
+ # Value of the parent column
+ def parent_id
+ self[parent_column_name]
+ end
- # Value of the right column
- def right
- self[right_column_name]
- end
+ # Value of the left column
+ def left
+ self[left_column_name]
+ end
- # Returns true if this is a root node.
- def root?
- parent_id.nil?
- end
+ # Value of the right column
+ def right
+ self[right_column_name]
+ end
- def leaf?
- new_record? || (right - left == 1)
- end
+ # Returns true if this is a root node.
+ def root?
+ parent_id.nil?
+ end
- # Returns true is this is a child node
- def child?
- !parent_id.nil?
- end
+ def leaf?
+ new_record? || (right - left == 1)
+ end
- # Returns root
- def root
- self_and_ancestors.where(parent_column_name => nil).first
- end
+ # Returns true is this is a child node
+ def child?
+ !parent_id.nil?
+ end
- # Returns the array of all parents and self
- def self_and_ancestors
- nested_set_scope.where([
- "#{self.class.quoted_table_name}.#{quoted_left_column_name} <= ? AND #{self.class.quoted_table_name}.#{quoted_right_column_name} >= ?", left, right
- ])
- end
+ # Returns root
+ def root
+ self_and_ancestors.where(parent_column_name => nil).first
+ end
- # Returns an array of all parents
- def ancestors
- without_self self_and_ancestors
- end
+ # Returns the array of all parents and self
+ def self_and_ancestors
+ nested_set_scope.where([
+ "#{self.class.quoted_table_name}.#{quoted_left_column_name} <= ? AND #{self.class.quoted_table_name}.#{quoted_right_column_name} >= ?", left, right
+ ])
+ end
- # Returns the array of all children of the parent, including self
- def self_and_siblings
- nested_set_scope.where(parent_column_name => parent_id)
- end
+ # Returns an array of all parents
+ def ancestors
+ without_self self_and_ancestors
+ end
- # Returns the array of all children of the parent, except self
- def siblings
- without_self self_and_siblings
- end
+ # Returns the array of all children of the parent, including self
+ def self_and_siblings
+ nested_set_scope.where(parent_column_name => parent_id)
+ end
- # Returns a set of all of its nested children which do not have children
- def leaves
- descendants.where("#{self.class.quoted_table_name}.#{quoted_right_column_name} - #{self.class.quoted_table_name}.#{quoted_left_column_name} = 1")
- end
+ # Returns the array of all children of the parent, except self
+ def siblings
+ without_self self_and_siblings
+ end
- # Returns the level of this object in the tree
- # root level is 0
- def level
- parent_id.nil? ? 0 : ancestors.count
- end
+ # Returns a set of all of its nested children which do not have children
+ def leaves
+ descendants.where("#{self.class.quoted_table_name}.#{quoted_right_column_name} - #{self.class.quoted_table_name}.#{quoted_left_column_name} = 1")
+ end
- # Returns a set of itself and all of its nested children
- def self_and_descendants
- nested_set_scope.where([
- "#{self.class.quoted_table_name}.#{quoted_left_column_name} >= ? AND #{self.class.quoted_table_name}.#{quoted_right_column_name} <= ?", left, right
- ])
- end
+ # Returns the level of this object in the tree
+ # root level is 0
+ def level
+ parent_id.nil? ? 0 : ancestors.count
+ end
- # Returns a set of all of its children and nested children
- def descendants
- without_self self_and_descendants
- end
+ # Returns a set of itself and all of its nested children
+ def self_and_descendants
+ nested_set_scope.where([
+ "#{self.class.quoted_table_name}.#{quoted_left_column_name} >= ? AND #{self.class.quoted_table_name}.#{quoted_right_column_name} <= ?", left, right
+ ])
+ end
- def is_descendant_of?(other)
- other.left < self.left && self.left < other.right && same_scope?(other)
- end
+ # Returns a set of all of its children and nested children
+ def descendants
+ without_self self_and_descendants
+ end
- def is_or_is_descendant_of?(other)
- other.left <= self.left && self.left < other.right && same_scope?(other)
- end
+ def is_descendant_of?(other)
+ other.left < self.left && self.left < other.right && same_scope?(other)
+ end
- def is_ancestor_of?(other)
- self.left < other.left && other.left < self.right && same_scope?(other)
- end
+ def is_or_is_descendant_of?(other)
+ other.left <= self.left && self.left < other.right && same_scope?(other)
+ end
- def is_or_is_ancestor_of?(other)
- self.left <= other.left && other.left < self.right && same_scope?(other)
- end
+ def is_ancestor_of?(other)
+ self.left < other.left && other.left < self.right && same_scope?(other)
+ end
- # Check if other model is in the same scope
- def same_scope?(other)
- Array(acts_as_nested_set_options[:scope]).all? do |attr|
- self.send(attr) == other.send(attr)
- end
- end
+ def is_or_is_ancestor_of?(other)
+ self.left <= other.left && other.left < self.right && same_scope?(other)
+ end
- # Find the first sibling to the left
- def left_sibling
- siblings.where(["#{self.class.quoted_table_name}.#{quoted_left_column_name} < ?", left]).
- order("#{self.class.quoted_table_name}.#{quoted_left_column_name} DESC").last
+ # Check if other model is in the same scope
+ def same_scope?(other)
+ Array(acts_as_nested_set_options[:scope]).all? do |attr|
+ self.send(attr) == other.send(attr)
end
+ end
- # Find the first sibling to the right
- def right_sibling
- siblings.where(["#{self.class.quoted_table_name}.#{quoted_left_column_name} > ?", left]).first
- end
+ # Find the first sibling to the left
+ def left_sibling
+ siblings.where(["#{self.class.quoted_table_name}.#{quoted_left_column_name} < ?", left]).
+ order("#{self.class.quoted_table_name}.#{quoted_left_column_name} DESC").last
+ end
- # Shorthand method for finding the left sibling and moving to the left of it.
- def move_left
- move_to_left_of left_sibling
- end
+ # Find the first sibling to the right
+ def right_sibling
+ siblings.where(["#{self.class.quoted_table_name}.#{quoted_left_column_name} > ?", left]).first
+ end
- # Shorthand method for finding the right sibling and moving to the right of it.
- def move_right
- move_to_right_of right_sibling
- end
+ # Shorthand method for finding the left sibling and moving to the left of it.
+ def move_left
+ move_to_left_of left_sibling
+ end
- # Move the node to the left of another node (you can pass id only)
- def move_to_left_of(node)
- move_to node, :left
- end
+ # Shorthand method for finding the right sibling and moving to the right of it.
+ def move_right
+ move_to_right_of right_sibling
+ end
- # Move the node to the left of another node (you can pass id only)
- def move_to_right_of(node)
- move_to node, :right
- end
+ # Move the node to the left of another node (you can pass id only)
+ def move_to_left_of(node)
+ move_to node, :left
+ end
- # Move the node to the child of another node (you can pass id only)
- def move_to_child_of(node)
- move_to node, :child
- end
+ # Move the node to the left of another node (you can pass id only)
+ def move_to_right_of(node)
+ move_to node, :right
+ end
- # Move the node to root nodes
- def move_to_root
- move_to nil, :root
- end
+ # Move the node to the child of another node (you can pass id only)
+ def move_to_child_of(node)
+ move_to node, :child
+ end
- def move_possible?(target)
- self != target && # Can't target self
- same_scope?(target) && # can't be in different scopes
- # !(left..right).include?(target.left..target.right) # this needs tested more
- # detect impossible move
- !((left <= target.left && right >= target.left) or (left <= target.right && right >= target.right))
- end
+ # Move the node to root nodes
+ def move_to_root
+ move_to nil, :root
+ end
- def to_text
- self_and_descendants.map do |node|
- "#{'*'*(node.level+1)} #{node.id} #{node.to_s} (#{node.parent_id}, #{node.left}, #{node.right})"
- end.join("\n")
- end
+ def move_possible?(target)
+ self != target && # Can't target self
+ same_scope?(target) && # can't be in different scopes
+ # !(left..right).include?(target.left..target.right) # this needs tested more
+ # detect impossible move
+ !((left <= target.left && right >= target.left) or (left <= target.right && right >= target.right))
+ end
- protected
+ def to_text
+ self_and_descendants.map do |node|
+ "#{'*'*(node.level+1)} #{node.id} #{node.to_s} (#{node.parent_id}, #{node.left}, #{node.right})"
+ end.join("\n")
+ end
- def without_self(scope)
- scope.where(["#{self.class.quoted_table_name}.#{self.class.primary_key} != ?", self])
- end
+ protected
- # All nested set queries should use this nested_set_scope, which performs finds on
- # the base ActiveRecord class, using the :scope declared in the acts_as_nested_set
- # declaration.
- def nested_set_scope(options = {})
- options = {:order => "#{self.class.quoted_table_name}.#{quoted_left_column_name}"}.merge(options)
- scopes = Array(acts_as_nested_set_options[:scope])
- options[:conditions] = scopes.inject({}) do |conditions,attr|
- conditions.merge attr => self[attr]
- end unless scopes.empty?
- self.class.base_class.scoped options
- end
+ def without_self(scope)
+ scope.where(["#{self.class.quoted_table_name}.#{self.class.primary_key} != ?", self])
+ end
- def store_new_parent
- @move_to_new_parent_id = send("#{parent_column_name}_changed?") ? parent_id : false
- true # force callback to return true
- end
+ # All nested set queries should use this nested_set_scope, which performs finds on
+ # the base ActiveRecord class, using the :scope declared in the acts_as_nested_set
+ # declaration.
+ def nested_set_scope(options = {})
+ options = {:order => "#{self.class.quoted_table_name}.#{quoted_left_column_name}"}.merge(options)
+ scopes = Array(acts_as_nested_set_options[:scope])
+ options[:conditions] = scopes.inject({}) do |conditions,attr|
+ conditions.merge attr => self[attr]
+ end unless scopes.empty?
+ self.class.base_class.scoped options
+ end
- def move_to_new_parent
- if @move_to_new_parent_id.nil?
- move_to_root
- elsif @move_to_new_parent_id
- move_to_child_of(@move_to_new_parent_id)
- end
- end
+ def store_new_parent
+ @move_to_new_parent_id = send("#{parent_column_name}_changed?") ? parent_id : false
+ true # force callback to return true
+ end
- # on creation, set automatically lft and rgt to the end of the tree
- def set_default_left_and_right
- highest_right_row = nested_set_scope(:order => "#{quoted_right_column_name} desc").find(:first, :limit => 1,:lock => true )
- maxright = highest_right_row ? (highest_right_row[right_column_name] || 0) : 0
- # adds the new node to the right of all existing nodes
- self[left_column_name] = maxright + 1
- self[right_column_name] = maxright + 2
+ def move_to_new_parent
+ if @move_to_new_parent_id.nil?
+ move_to_root
+ elsif @move_to_new_parent_id
+ move_to_child_of(@move_to_new_parent_id)
end
+ end
- def in_tenacious_transaction(&block)
- retry_count = 0
- begin
- transaction(&block)
- rescue ActiveRecord::StatementInvalid => error
- raise unless connection.open_transactions.zero?
- raise unless error.message =~ /Deadlock found when trying to get lock|Lock wait timeout exceeded/
- raise unless retry_count < 10
- retry_count += 1
- logger.info "Deadlock detected on retry #{retry_count}, restarting transaction"
- sleep(rand(retry_count)*0.1) # Aloha protocol
- retry
- end
- end
+ # on creation, set automatically lft and rgt to the end of the tree
+ def set_default_left_and_right
+ highest_right_row = nested_set_scope(:order => "#{quoted_right_column_name} desc").find(:first, :limit => 1,:lock => true )
+ maxright = highest_right_row ? (highest_right_row[right_column_name] || 0) : 0
+ # adds the new node to the right of all existing nodes
+ self[left_column_name] = maxright + 1
+ self[right_column_name] = maxright + 2
+ end
- # Prunes a branch off of the tree, shifting all of the elements on the right
- # back to the left so the counts still work.
- def destroy_descendants
- return if right.nil? || left.nil? || skip_before_destroy
+ def in_tenacious_transaction(&block)
+ retry_count = 0
+ begin
+ transaction(&block)
+ rescue ActiveRecord::StatementInvalid => error
+ raise unless connection.open_transactions.zero?
+ raise unless error.message =~ /Deadlock found when trying to get lock|Lock wait timeout exceeded/
+ raise unless retry_count < 10
+ retry_count += 1
+ logger.info "Deadlock detected on retry #{retry_count}, restarting transaction"
+ sleep(rand(retry_count)*0.1) # Aloha protocol
+ retry
+ end
+ end
- in_tenacious_transaction do
- reload_nested_set
- # select the rows in the model that extend past the deletion point and apply a lock
- self.class.base_class.find(:all,
- :select => "id",
- :conditions => ["#{quoted_left_column_name} >= ?", left],
- :lock => true
- )
+ # Prunes a branch off of the tree, shifting all of the elements on the right
+ # back to the left so the counts still work.
+ def destroy_descendants
+ return if right.nil? || left.nil? || skip_before_destroy
+
+ in_tenacious_transaction do
+ reload_nested_set
+ # select the rows in the model that extend past the deletion point and apply a lock
+ self.class.base_class.find(:all,
+ :select => "id",
+ :conditions => ["#{quoted_left_column_name} >= ?", left],
+ :lock => true
+ )
- if acts_as_nested_set_options[:dependent] == :destroy
- descendants.each do |model|
- model.skip_before_destroy = true
- model.destroy
- end
- else
- nested_set_scope.delete_all(
- ["#{quoted_left_column_name} > ? AND #{quoted_right_column_name} < ?",
- left, right]
- )
+ if acts_as_nested_set_options[:dependent] == :destroy
+ descendants.each do |model|
+ model.skip_before_destroy = true
+ model.destroy
end
-
- # update lefts and rights for remaining nodes
- diff = right - left + 1
- nested_set_scope.update_all(
- ["#{quoted_left_column_name} = (#{quoted_left_column_name} - ?)", diff],
- ["#{quoted_left_column_name} > ?", right]
+ else
+ nested_set_scope.delete_all(
+ ["#{quoted_left_column_name} > ? AND #{quoted_right_column_name} < ?",
+ left, right]
)
- nested_set_scope.update_all(
- ["#{quoted_right_column_name} = (#{quoted_right_column_name} - ?)", diff],
- ["#{quoted_right_column_name} > ?", right]
+ end
+
+ # update lefts and rights for remaining nodes
+ diff = right - left + 1
+ nested_set_scope.update_all(
+ ["#{quoted_left_column_name} = (#{quoted_left_column_name} - ?)", diff],
+ ["#{quoted_left_column_name} > ?", right]
+ )
+ nested_set_scope.update_all(
+ ["#{quoted_right_column_name} = (#{quoted_right_column_name} - ?)", diff],
+ ["#{quoted_right_column_name} > ?", right]
)
reload
# Don't allow multiple calls to destroy to corrupt the set
- self.skip_before_destroy = true
- end
- end
-
- # reload left, right, and parent
- def reload_nested_set
- reload(
- :select => "#{quoted_left_column_name}, #{quoted_right_column_name}, #{quoted_parent_column_name}",
- :lock => true
- )
+ self.skip_before_destroy = true
end
+ end
- def move_to(target, position)
- raise ActiveRecord::ActiveRecordError, "You cannot move a new node" if self.new_record?
- run_callbacks :move do
- in_tenacious_transaction do
- if target.is_a? self.class.base_class
- target.reload_nested_set
- elsif position != :root
- # load object if node is not an object
- target = nested_set_scope.find(target)
- end
- self.reload_nested_set
+ # reload left, right, and parent
+ def reload_nested_set
+ reload(
+ :select => "#{quoted_left_column_name}, #{quoted_right_column_name}, #{quoted_parent_column_name}",
+ :lock => true
+ )
+ end
- unless position == :root || move_possible?(target)
- raise ActiveRecord::ActiveRecordError, "Impossible move, target node cannot be inside moved tree."
- end
+ def move_to(target, position)
+ raise ActiveRecord::ActiveRecordError, "You cannot move a new node" if self.new_record?
+ run_callbacks :move do
+ in_tenacious_transaction do
+ if target.is_a? self.class.base_class
+ target.reload_nested_set
+ elsif position != :root
+ # load object if node is not an object
+ target = nested_set_scope.find(target)
+ end
+ self.reload_nested_set
- bound = case position
- when :child; target[right_column_name]
- when :left; target[left_column_name]
- when :right; target[right_column_name] + 1
- when :root; 1
- else raise ActiveRecord::ActiveRecordError, "Position should be :child, :left, :right or :root ('#{position}' received)."
- end
+ unless position == :root || move_possible?(target)
+ raise ActiveRecord::ActiveRecordError, "Impossible move, target node cannot be inside moved tree."
+ end
- if bound > self[right_column_name]
- bound = bound - 1
- other_bound = self[right_column_name] + 1
- else
- other_bound = self[left_column_name] - 1
- end
+ bound = case position
+ when :child; target[right_column_name]
+ when :left; target[left_column_name]
+ when :right; target[right_column_name] + 1
+ when :root; 1
+ else raise ActiveRecord::ActiveRecordError, "Position should be :child, :left, :right or :root ('#{position}' received)."
+ end
- # there would be no change
- return if bound == self[right_column_name] || bound == self[left_column_name]
+ if bound > self[right_column_name]
+ bound = bound - 1
+ other_bound = self[right_column_name] + 1
+ else
+ other_bound = self[left_column_name] - 1
+ end
- # we have defined the boundaries of two non-overlapping intervals,
- # so sorting puts both the intervals and their boundaries in order
- a, b, c, d = [self[left_column_name], self[right_column_name], bound, other_bound].sort
+ # there would be no change
+ return if bound == self[right_column_name] || bound == self[left_column_name]
- # select the rows in the model between a and d, and apply a lock
- self.class.base_class.select('id').lock(true).where(
- ["#{quoted_left_column_name} >= :a and #{quoted_right_column_name} <= :d", {:a => a, :d => d}]
- )
+ # we have defined the boundaries of two non-overlapping intervals,
+ # so sorting puts both the intervals and their boundaries in order
+ a, b, c, d = [self[left_column_name], self[right_column_name], bound, other_bound].sort
- new_parent = case position
- when :child; target.id
- when :root; nil
- else target[parent_column_name]
- end
+ # select the rows in the model between a and d, and apply a lock
+ self.class.base_class.select('id').lock(true).where(
+ ["#{quoted_left_column_name} >= :a and #{quoted_right_column_name} <= :d", {:a => a, :d => d}]
+ )
- self.nested_set_scope.update_all([
- "#{quoted_left_column_name} = CASE " +
- "WHEN #{quoted_left_column_name} BETWEEN :a AND :b " +
- "THEN #{quoted_left_column_name} + :d - :b " +
- "WHEN #{quoted_left_column_name} BETWEEN :c AND :d " +
- "THEN #{quoted_left_column_name} + :a - :c " +
- "ELSE #{quoted_left_column_name} END, " +
- "#{quoted_right_column_name} = CASE " +
- "WHEN #{quoted_right_column_name} BETWEEN :a AND :b " +
- "THEN #{quoted_right_column_name} + :d - :b " +
- "WHEN #{quoted_right_column_name} BETWEEN :c AND :d " +
- "THEN #{quoted_right_column_name} + :a - :c " +
- "ELSE #{quoted_right_column_name} END, " +
- "#{quoted_parent_column_name} = CASE " +
- "WHEN #{self.class.base_class.primary_key} = :id THEN :new_parent " +
- "ELSE #{quoted_parent_column_name} END",
- {:a => a, :b => b, :c => c, :d => d, :id => self.id, :new_parent => new_parent}
- ])
+ new_parent = case position
+ when :child; target.id
+ when :root; nil
+ else target[parent_column_name]
end
- target.reload_nested_set if target
- self.reload_nested_set
+
+ self.nested_set_scope.update_all([
+ "#{quoted_left_column_name} = CASE " +
+ "WHEN #{quoted_left_column_name} BETWEEN :a AND :b " +
+ "THEN #{quoted_left_column_name} + :d - :b " +
+ "WHEN #{quoted_left_column_name} BETWEEN :c AND :d " +
+ "THEN #{quoted_left_column_name} + :a - :c " +
+ "ELSE #{quoted_left_column_name} END, " +
+ "#{quoted_right_column_name} = CASE " +
+ "WHEN #{quoted_right_column_name} BETWEEN :a AND :b " +
+ "THEN #{quoted_right_column_name} + :d - :b " +
+ "WHEN #{quoted_right_column_name} BETWEEN :c AND :d " +
+ "THEN #{quoted_right_column_name} + :a - :c " +
+ "ELSE #{quoted_right_column_name} END, " +
+ "#{quoted_parent_column_name} = CASE " +
+ "WHEN #{self.class.base_class.primary_key} = :id THEN :new_parent " +
+ "ELSE #{quoted_parent_column_name} END",
+ {:a => a, :b => b, :c => c, :d => d, :id => self.id, :new_parent => new_parent}
+ ])
end
+ target.reload_nested_set if target
+ self.reload_nested_set
end
-
end
end
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