- def delete_with_history(user)
- if self.visible
- if WayNode.find(:first, :joins => "INNER JOIN current_ways ON current_ways.id = current_way_nodes.id", :conditions => [ "current_ways.visible = 1 AND current_way_nodes.node_id = ?", self.id ])
- raise OSM::APIPreconditionFailedError.new
- elsif RelationMember.find(:first, :joins => "INNER JOIN current_relations ON current_relations.id=current_relation_members.id", :conditions => [ "visible = 1 AND member_type='node' and member_id=?", self.id])
- raise OSM::APIPreconditionFailedError.new
- else
- self.user_id = user.id
- self.visible = 0
- save_with_history!
- end
- else
- raise OSM::APIAlreadyDeletedError.new
+ # 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.
+ Node.transaction do
+ self.lock!
+ check_consistency(self, new_node, user)
+ ways = Way.joins(:way_nodes).where(:visible => true, :current_way_nodes => { :node_id => id }).order(:id)
+ raise OSM::APIPreconditionFailedError.new("Node #{self.id} is still used by ways #{ways.collect { |w| w.id }.join(",")}.") unless ways.empty?
+
+ rels = Relation.joins(:relation_members).where(:visible => true, :current_relation_members => { :member_type => "Node", :member_id => id }).order(:id)
+ raise OSM::APIPreconditionFailedError.new("Node #{self.id} is still used by relations #{rels.collect { |r| r.id }.join(",")}.") unless rels.empty?
+
+ self.changeset_id = new_node.changeset_id
+ self.tags = {}
+ self.visible = false
+
+ # update the changeset with the deleted position
+ changeset.update_bbox!(bbox)
+
+ save_with_history!