+ # check only the new nodes, for efficiency - old nodes having been checked last time and can't
+ # be deleted when they're in-use.
+ new_nds = (self.nds - old_nodes).sort.uniq
+
+ unless new_nds.empty?
+ db_nds = Node.where(:id => new_nds, :visible => true)
+
+ if db_nds.length < new_nds.length
+ missing = new_nds - db_nds.collect { |n| n.id }
+ raise OSM::APIPreconditionFailedError.new("Way #{self.id} requires the nodes with id in (#{missing.join(',')}), which either do not exist, or are not visible.")
+ end
+ end
+
+ return true
+ end
+
+ def delete_with_history!(new_way, user)
+ unless self.visible
+ raise OSM::APIAlreadyDeletedError.new("way", new_way.id)
+ end
+
+ # need to start the transaction here, so that the database can
+ # provide repeatable reads for the used-by checks. this means it
+ # shouldn't be possible to get race conditions.
+ Way.transaction do
+ self.lock!
+ check_consistency(self, new_way, user)
+ rels = Relation.joins(:relation_members).where(:visible => true, :current_relation_members => { :member_type => "Way", :member_id => id }).order(:id)
+ raise OSM::APIPreconditionFailedError.new("Way #{self.id} is still used by relations #{rels.collect { |r| r.id }.join(",")}.") unless rels.empty?
+
+ self.changeset_id = new_way.changeset_id
+ self.changeset = new_way.changeset
+
+ self.tags = []
+ self.nds = []
+ self.visible = false
+ save_with_history!