comparison .svn/pristine/fd/fd672f720e53aab0a0184fd9c83dcdbc26d28825.svn-base @ 1298:4f746d8966dd redmine_2.3_integration

Merge from redmine-2.3 branch to create new branch redmine-2.3-integration

+module CollectiveIdea #:nodoc:
+  module Acts #:nodoc:
+    module NestedSet #:nodoc:
+
+      # 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.
+      #
+      #   item.children.create(:name => "child1")
+      #
+
+      # 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.
+      # * +:counter_cache+ adds a counter cache for the number of children.
+      #   defaults to false.
+      #   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 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',
+          :dependent => :delete_all, # or :destroy
+          :counter_cache => false,
+          :order => 'id'
+        }.merge(options)
+
+        if options[:scope].is_a?(Symbol) && options[:scope].to_s !~ /_id$/
+          options[:scope] = "#{options[:scope]}_id".intern
+        end
+
+        class_attribute :acts_as_nested_set_options
+        self.acts_as_nested_set_options = options
+
+        include CollectiveIdea::Acts::NestedSet::Model
+        include Columns
+        extend Columns
+
+        belongs_to :parent, :class_name => self.base_class.to_s,
+          :foreign_key => parent_column_name,
+          :counter_cache => options[:counter_cache],
+          :inverse_of => :children
+        has_many :children, :class_name => self.base_class.to_s,
+          :foreign_key => parent_column_name, :order => left_column_name,
+          :inverse_of => :parent,
+          :before_add    => options[:before_add],
+          :after_add     => options[:after_add],
+          :before_remove => options[:before_remove],
+          :after_remove  => options[:after_remove]
+
+        attr_accessor :skip_before_destroy
+
+        before_create  :set_default_left_and_right
+        before_save    :store_new_parent
+        after_save     :move_to_new_parent
+        before_destroy :destroy_descendants
+
+        # no assignment to structure fields
+        [left_column_name, right_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
+
+        define_model_callbacks :move
+      end
+
+      module Model
+        extend ActiveSupport::Concern
+
+        module ClassMethods
+          # Returns the first root
+          def root
+            roots.first
+          end
+
+          def roots
+            where(parent_column_name => nil).order(quoted_left_column_name)
+          end
+
+          def leaves
+            where("#{quoted_right_column_name} - #{quoted_left_column_name} = 1").order(quoted_left_column_name)
+          end
+
+          def valid?
+            left_and_rights_valid? && no_duplicates_for_columns? && all_roots_valid?
+          end
+
+          def left_and_rights_valid?
+            joins("LEFT OUTER JOIN #{quoted_table_name} AS parent ON " +
+                "#{quoted_table_name}.#{quoted_parent_column_name} = parent.#{primary_key}").
+            where(
+                "#{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}))"
+            ).count == 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
+              select("#{scope_string}#{column}, COUNT(#{column})").
+                  group("#{scope_string}#{column}").
+                  having("COUNT(#{column}) > 1").
+                  first.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|
+              (root.left > left && root.right > right).tap 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!(validate_nodes = true)
+            # Don't rebuild a valid tree.
+            return true if valid?
+
+            scope = lambda{|node|}
+            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
+              where(["#{quoted_parent_column_name} = ? #{scope.call(node)}", node]).order(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!(:validate => validate_nodes)
+            end
+
+            # Find root node(s)
+            root_nodes = where("#{quoted_parent_column_name} IS NULL").order(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
+
+          # Iterates over tree elements and determines the current level in the tree.
+          # Only accepts default ordering, odering by an other column than lft
+          # does not work. This method is much more efficent than calling level
+          # because it doesn't require any additional database queries.
+          #
+          # Example:
+          #    Category.each_with_level(Category.root.self_and_descendants) do |o, level|
+          #
+          def each_with_level(objects)
+            path = [nil]
+            objects.each do |o|
+              if o.parent_id != path.last
+                # we are on a new level, did we decent or ascent?
+                if path.include?(o.parent_id)
+                  # remove wrong wrong tailing paths elements
+                  path.pop while path.last != o.parent_id
+                else
+                  path << o.parent_id
+                end
+              end
+              yield(o, path.length - 1)
+            end
+          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%'")
+
+        # 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?
+          new_record? || (right - left == 1)
+        end
+
+        # Returns true is this is a child node
+        def child?
+          !parent_id.nil?
+        end
+
+        # Returns root
+        def root
+          self_and_ancestors.where(parent_column_name => nil).first
+        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 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.where(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.where("#{self.class.quoted_table_name}.#{quoted_right_column_name} - #{self.class.quoted_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.where([
+            "#{self.class.quoted_table_name}.#{quoted_left_column_name} >= ? AND #{self.class.quoted_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
+
+        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.where(["#{self.class.quoted_table_name}.#{quoted_left_column_name} < ?", left]).
+                  order("#{self.class.quoted_table_name}.#{quoted_left_column_name} DESC").last
+        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 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.where(["#{self.class.quoted_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 = {})
+          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 store_new_parent
+          @move_to_new_parent_id = send("#{parent_column_name}_changed?") ? parent_id : false
+          true # force callback to return true
+        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
+
+        # 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").limit(1).lock(true).first
+          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
+
+        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
+
+        # 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.
+              select("id").
+              where("#{quoted_left_column_name} >= ?", left).
+              lock(true).
+              all
+
+            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]
+              )
+            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
+          )
+        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
+
+              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
+
+              # 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}]
+              )
+
+              new_parent = case position
+                when :child;  target.id
+                when :root;   nil
+                else          target[parent_column_name]
+              end
+
+              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
+
+      # 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
+
+    end
+  end
+end