diff options
Diffstat (limited to 'vendor/plugins/awesome_nested_set/lib/awesome_nested_set.rb')
| -rw-r--r-- | vendor/plugins/awesome_nested_set/lib/awesome_nested_set.rb | 547 |
1 files changed, 547 insertions, 0 deletions
diff --git a/vendor/plugins/awesome_nested_set/lib/awesome_nested_set.rb b/vendor/plugins/awesome_nested_set/lib/awesome_nested_set.rb new file mode 100644 index 000000000..fb67341b6 --- /dev/null +++ b/vendor/plugins/awesome_nested_set/lib/awesome_nested_set.rb @@ -0,0 +1,547 @@ +module CollectiveIdea #:nodoc: + module Acts #:nodoc: + module NestedSet #:nodoc: + def self.included(base) + base.extend(SingletonMethods) + end + + # This acts provides Nested Set functionality. Nested Set is a smart way to implement + # an _ordered_ tree, with the added feature that you can select the children and all of their + # descendants with a single query. The drawback is that insertion or move need some complex + # sql queries. But everything is done here by this module! + # + # Nested sets are appropriate each time you want either an orderd tree (menus, + # commercial categories) or an efficient way of querying big trees (threaded posts). + # + # == API + # + # Methods names are aligned with acts_as_tree as much as possible, to make replacment from one + # by another easier, except for the creation: + # + # in acts_as_tree: + # item.children.create(:name => "child1") + # + # in acts_as_nested_set: + # # adds a new item at the "end" of the tree, i.e. with child.left = max(tree.right)+1 + # child = MyClass.new(:name => "child1") + # child.save + # # now move the item to its right place + # child.move_to_child_of my_item + # + # You can pass an id or an object to: + # * <tt>#move_to_child_of</tt> + # * <tt>#move_to_right_of</tt> + # * <tt>#move_to_left_of</tt> + # + module SingletonMethods + # Configuration options are: + # + # * +:parent_column+ - specifies the column name to use for keeping the position integer (default: parent_id) + # * +:left_column+ - column name for left boundry data, default "lft" + # * +:right_column+ - column name for right boundry data, default "rgt" + # * +:scope+ - restricts what is to be considered a list. Given a symbol, it'll attach "_id" + # (if it hasn't been already) and use that as the foreign key restriction. You + # can also pass an array to scope by multiple attributes. + # Example: <tt>acts_as_nested_set :scope => [:notable_id, :notable_type]</tt> + # * +:dependent+ - behavior for cascading destroy. If set to :destroy, all the + # child objects are destroyed alongside this object by calling their destroy + # method. If set to :delete_all (default), all the child objects are deleted + # without calling their destroy method. + # + # See CollectiveIdea::Acts::NestedSet::ClassMethods for a list of class methods and + # CollectiveIdea::Acts::NestedSet::InstanceMethods for a list of instance methods added + # to acts_as_nested_set models + def acts_as_nested_set(options = {}) + options = { + :parent_column => 'parent_id', + :left_column => 'lft', + :right_column => 'rgt', + :order => 'id', + :dependent => :delete_all, # or :destroy + }.merge(options) + + if options[:scope].is_a?(Symbol) && options[:scope].to_s !~ /_id$/ + options[:scope] = "#{options[:scope]}_id".intern + end + + write_inheritable_attribute :acts_as_nested_set_options, options + class_inheritable_reader :acts_as_nested_set_options + + include Comparable + include Columns + include InstanceMethods + extend Columns + extend ClassMethods + + # no bulk assignment + attr_protected left_column_name.intern, + right_column_name.intern, + parent_column_name.intern + + before_create :set_default_left_and_right + before_destroy :prune_from_tree + + # no assignment to structure fields + [left_column_name, right_column_name, parent_column_name].each do |column| + module_eval <<-"end_eval", __FILE__, __LINE__ + def #{column}=(x) + raise ActiveRecord::ActiveRecordError, "Unauthorized assignment to #{column}: it's an internal field handled by acts_as_nested_set code, use move_to_* methods instead." + end + end_eval + end + + named_scope :roots, :conditions => {parent_column_name => nil}, :order => quoted_left_column_name + named_scope :leaves, :conditions => "#{quoted_right_column_name} - #{quoted_left_column_name} = 1", :order => quoted_left_column_name + if self.respond_to?(:define_callbacks) + define_callbacks("before_move", "after_move") + end + + + end + + end + + module ClassMethods + + # Returns the first root + def root + roots.find(:first) + end + + def valid? + left_and_rights_valid? && no_duplicates_for_columns? && all_roots_valid? + end + + def left_and_rights_valid? + count( + :joins => "LEFT OUTER JOIN #{quoted_table_name} AS parent ON " + + "#{quoted_table_name}.#{quoted_parent_column_name} = parent.#{primary_key}", + :conditions => + "#{quoted_table_name}.#{quoted_left_column_name} IS NULL OR " + + "#{quoted_table_name}.#{quoted_right_column_name} IS NULL OR " + + "#{quoted_table_name}.#{quoted_left_column_name} >= " + + "#{quoted_table_name}.#{quoted_right_column_name} OR " + + "(#{quoted_table_name}.#{quoted_parent_column_name} IS NOT NULL AND " + + "(#{quoted_table_name}.#{quoted_left_column_name} <= parent.#{quoted_left_column_name} OR " + + "#{quoted_table_name}.#{quoted_right_column_name} >= parent.#{quoted_right_column_name}))" + ) == 0 + end + + def no_duplicates_for_columns? + scope_string = Array(acts_as_nested_set_options[:scope]).map do |c| + connection.quote_column_name(c) + end.push(nil).join(", ") + [quoted_left_column_name, quoted_right_column_name].all? do |column| + # No duplicates + find(:first, + :select => "#{scope_string}#{column}, COUNT(#{column})", + :group => "#{scope_string}#{column} + HAVING COUNT(#{column}) > 1").nil? + end + end + + # Wrapper for each_root_valid? that can deal with scope. + def all_roots_valid? + if acts_as_nested_set_options[:scope] + roots(:group => scope_column_names).group_by{|record| scope_column_names.collect{|col| record.send(col.to_sym)}}.all? do |scope, grouped_roots| + each_root_valid?(grouped_roots) + end + else + each_root_valid?(roots) + end + end + + def each_root_valid?(roots_to_validate) + left = right = 0 + roots_to_validate.all? do |root| + returning(root.left > left && root.right > right) do + left = root.left + right = root.right + end + end + end + + # Rebuilds the left & rights if unset or invalid. Also very useful for converting from acts_as_tree. + def rebuild! + # Don't rebuild a valid tree. + return true if valid? + + scope = lambda{} + if acts_as_nested_set_options[:scope] + scope = lambda{|node| + scope_column_names.inject(""){|str, column_name| + str << "AND #{connection.quote_column_name(column_name)} = #{connection.quote(node.send(column_name.to_sym))} " + } + } + end + indices = {} + + set_left_and_rights = lambda do |node| + # set left + node[left_column_name] = indices[scope.call(node)] += 1 + # find + find(:all, :conditions => ["#{quoted_parent_column_name} = ? #{scope.call(node)}", node], :order => "#{quoted_left_column_name}, #{quoted_right_column_name}, #{acts_as_nested_set_options[:order]}").each{|n| set_left_and_rights.call(n) } + # set right + node[right_column_name] = indices[scope.call(node)] += 1 + node.save! + end + + # Find root node(s) + root_nodes = find(:all, :conditions => "#{quoted_parent_column_name} IS NULL", :order => "#{quoted_left_column_name}, #{quoted_right_column_name}, #{acts_as_nested_set_options[:order]}").each do |root_node| + # setup index for this scope + indices[scope.call(root_node)] ||= 0 + set_left_and_rights.call(root_node) + end + end + end + + # Mixed into both classes and instances to provide easy access to the column names + module Columns + def left_column_name + acts_as_nested_set_options[:left_column] + end + + def right_column_name + acts_as_nested_set_options[:right_column] + end + + def parent_column_name + acts_as_nested_set_options[:parent_column] + end + + def scope_column_names + Array(acts_as_nested_set_options[:scope]) + end + + def quoted_left_column_name + connection.quote_column_name(left_column_name) + end + + def quoted_right_column_name + connection.quote_column_name(right_column_name) + end + + def quoted_parent_column_name + connection.quote_column_name(parent_column_name) + end + + def quoted_scope_column_names + scope_column_names.collect {|column_name| connection.quote_column_name(column_name) } + end + end + + # Any instance method that returns a collection makes use of Rails 2.1's named_scope (which is bundled for Rails 2.0), so it can be treated as a finder. + # + # 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 right column + def right + self[right_column_name] + end + + # Returns true if this is a root node. + def root? + parent_id.nil? + end + + def leaf? + right - left == 1 + end + + # Returns true is this is a child node + def child? + !parent_id.nil? + end + + # order by left column + def <=>(x) + left <=> x.left + end + + # Redefine to act like active record + def ==(comparison_object) + comparison_object.equal?(self) || + (comparison_object.instance_of?(self.class) && + comparison_object.id == id && + !comparison_object.new_record?) + end + + # Returns root + def root + self_and_ancestors.find(:first) + end + + # Returns the immediate parent + def parent + nested_set_scope.find_by_id(parent_id) if parent_id + end + + # Returns the array of all parents and self + def self_and_ancestors + nested_set_scope.scoped :conditions => [ + "#{self.class.table_name}.#{quoted_left_column_name} <= ? AND #{self.class.table_name}.#{quoted_right_column_name} >= ?", left, right + ] + end + + # Returns an array of all parents + def ancestors + without_self self_and_ancestors + end + + # Returns the array of all children of the parent, including self + def self_and_siblings + nested_set_scope.scoped :conditions => {parent_column_name => parent_id} + end + + # Returns the array of all children of the parent, except self + def siblings + without_self self_and_siblings + end + + # Returns a set of all of its nested children which do not have children + def leaves + descendants.scoped :conditions => "#{self.class.table_name}.#{quoted_right_column_name} - #{self.class.table_name}.#{quoted_left_column_name} = 1" + 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 itself and all of its nested children + def self_and_descendants + nested_set_scope.scoped :conditions => [ + "#{self.class.table_name}.#{quoted_left_column_name} >= ? AND #{self.class.table_name}.#{quoted_right_column_name} <= ?", left, right + ] + end + + # Returns a set of all of its children and nested children + def descendants + without_self self_and_descendants + end + + # Returns a set of only this entry's immediate children + def children + nested_set_scope.scoped :conditions => {parent_column_name => self} + end + + def is_descendant_of?(other) + other.left < self.left && self.left < other.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_ancestor_of?(other) + self.left < other.left && other.left < self.right && same_scope?(other) + end + + def is_or_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 + + # Find the first sibling to the left + def left_sibling + siblings.find(:first, :conditions => ["#{self.class.table_name}.#{quoted_left_column_name} < ?", left], + :order => "#{self.class.table_name}.#{quoted_left_column_name} DESC") + end + + # Find the first sibling to the right + def right_sibling + siblings.find(:first, :conditions => ["#{self.class.table_name}.#{quoted_left_column_name} > ?", left]) + 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 + + # 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_left_of(node) + move_to node, :left + 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 child of another node (you can pass id only) + def move_to_child_of(node) + move_to node, :child + end + + # Move the node to root nodes + def move_to_root + move_to nil, :root + 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 + + 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 + + protected + + def without_self(scope) + scope.scoped :conditions => ["#{self.class.table_name}.#{self.class.primary_key} != ?", self] + 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 = {:order => quoted_left_column_name} + 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 + + # on creation, set automatically lft and rgt to the end of the tree + def set_default_left_and_right + maxright = nested_set_scope.maximum(right_column_name) || 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 prune_from_tree + return if right.nil? || left.nil? + diff = right - left + 1 + + delete_method = acts_as_nested_set_options[:dependent] == :destroy ? + :destroy_all : :delete_all + + self.class.base_class.transaction do + nested_set_scope.send(delete_method, + ["#{quoted_left_column_name} > ? AND #{quoted_right_column_name} < ?", + left, right] + ) + 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] + ) + 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}") + end + + def move_to(target, position) + raise ActiveRecord::ActiveRecordError, "You cannot move a new node" if self.new_record? + return if callback(:before_move) == false + 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 + + unless position == :root || move_possible?(target) + raise ActiveRecord::ActiveRecordError, "Impossible move, target node cannot be inside moved tree." + 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 + + 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 + + # there would be no change + return if bound == self[right_column_name] || bound == self[left_column_name] + + # 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 + + self.class.base_class.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} + ], nested_set_scope.proxy_options[:conditions]) + end + target.reload_nested_set if target + self.reload_nested_set + callback(:after_move) + end + + end + + end + end +end |