openstreetmap-website/app/models/relation.rb
2022-03-02 15:00:25 +00:00

382 lines
14 KiB
Ruby

# == Schema Information
#
# Table name: current_relations
#
# id :bigint(8) not null, primary key
# changeset_id :bigint(8) not null
# timestamp :datetime not null
# visible :boolean not null
# version :bigint(8) not null
#
# Indexes
#
# current_relations_timestamp_idx (timestamp)
#
# Foreign Keys
#
# current_relations_changeset_id_fkey (changeset_id => changesets.id)
#
class Relation < ApplicationRecord
require "xml/libxml"
include ConsistencyValidations
include NotRedactable
self.table_name = "current_relations"
belongs_to :changeset
has_many :old_relations, -> { order(:version) }, :inverse_of => :current_relation
has_many :relation_members, -> { order(:sequence_id) }, :inverse_of => :relation
has_many :relation_tags
has_many :containing_relation_members, :class_name => "RelationMember", :as => :member
has_many :containing_relations, :class_name => "Relation", :through => :containing_relation_members, :source => :relation
validates :id, :uniqueness => true, :presence => { :on => :update },
:numericality => { :on => :update, :only_integer => true }
validates :version, :presence => true,
:numericality => { :only_integer => true }
validates :timestamp, :presence => true
validates :changeset, :associated => true
validates :visible, :inclusion => [true, false]
scope :visible, -> { where(:visible => true) }
scope :invisible, -> { where(:visible => false) }
scope :nodes, ->(*ids) { joins(:relation_members).where(:current_relation_members => { :member_type => "Node", :member_id => ids.flatten }) }
scope :ways, ->(*ids) { joins(:relation_members).where(:current_relation_members => { :member_type => "Way", :member_id => ids.flatten }) }
scope :relations, ->(*ids) { joins(:relation_members).where(:current_relation_members => { :member_type => "Relation", :member_id => ids.flatten }) }
TYPES = %w[node way relation].freeze
def self.from_xml(xml, create: false)
p = XML::Parser.string(xml, :options => XML::Parser::Options::NOERROR)
doc = p.parse
pt = doc.find_first("//osm/relation")
if pt
Relation.from_xml_node(pt, :create => create)
else
raise OSM::APIBadXMLError.new("node", xml, "XML doesn't contain an osm/relation element.")
end
rescue LibXML::XML::Error, ArgumentError => e
raise OSM::APIBadXMLError.new("relation", xml, e.message)
end
def self.from_xml_node(pt, create: false)
relation = Relation.new
raise OSM::APIBadXMLError.new("relation", pt, "Version is required when updating") unless create || !pt["version"].nil?
relation.version = pt["version"]
raise OSM::APIBadXMLError.new("relation", pt, "Changeset id is missing") if pt["changeset"].nil?
relation.changeset_id = pt["changeset"]
unless create
raise OSM::APIBadXMLError.new("relation", pt, "ID is required when updating") if pt["id"].nil?
relation.id = pt["id"].to_i
# .to_i will return 0 if there is no number that can be parsed.
# We want to make sure that there is no id with zero anyway
raise OSM::APIBadUserInput, "ID of relation cannot be zero when updating." if relation.id.zero?
end
# We don't care about the timestamp nor the visibility as these are either
# set explicitly or implicit in the action. The visibility is set to true,
# and manually set to false before the actual delete.
relation.visible = true
# Start with no tags
relation.tags = {}
# Add in any tags from the XML
pt.find("tag").each do |tag|
raise OSM::APIBadXMLError.new("relation", pt, "tag is missing key") if tag["k"].nil?
raise OSM::APIBadXMLError.new("relation", pt, "tag is missing value") if tag["v"].nil?
relation.add_tag_keyval(tag["k"], tag["v"])
end
# need to initialise the relation members array explicitly, as if this
# isn't done for a new relation then @members attribute will be nil,
# and the members will be loaded from the database instead of being
# empty, as intended.
relation.members = []
pt.find("member").each do |member|
# member_type =
raise OSM::APIBadXMLError.new("relation", pt, "The #{member['type']} is not allowed only, #{TYPES.inspect} allowed") unless TYPES.include? member["type"]
# member_ref = member['ref']
# member_role
member["role"] ||= "" # Allow the upload to not include this, in which case we default to an empty string.
relation.add_member(member["type"].classify, member["ref"], member["role"])
end
raise OSM::APIBadUserInput, "Some bad xml in relation" if relation.nil?
relation
end
# FIXME: is this really needed?
def members
@members ||= relation_members.map do |member|
[member.member_type, member.member_id, member.member_role]
end
end
def tags
@tags ||= relation_tags.to_h { |t| [t.k, t.v] }
end
attr_writer :members, :tags
def add_member(type, id, role)
@members ||= []
@members << [type, id.to_i, role]
end
def add_tag_keyval(k, v)
@tags ||= {}
# duplicate tags are now forbidden, so we can't allow values
# in the hash to be overwritten.
raise OSM::APIDuplicateTagsError.new("relation", id, k) if @tags.include? k
@tags[k] = v
end
##
# updates the changeset bounding box to contain the bounding box of
# the element with given +type+ and +id+. this only works with nodes
# and ways at the moment, as they're the only elements to respond to
# the :bbox call.
def update_changeset_element(type, id)
element = Kernel.const_get(type.capitalize).find(id)
changeset.update_bbox! element.bbox
end
def delete_with_history!(new_relation, user)
raise OSM::APIAlreadyDeletedError.new("relation", new_relation.id) unless visible
# 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.
Relation.transaction do
lock!
check_consistency(self, new_relation, user)
# This will check to see if this relation is used by another relation
rel = RelationMember.joins(:relation).find_by("visible = ? AND member_type = 'Relation' and member_id = ? ", true, id)
raise OSM::APIPreconditionFailedError, "The relation #{new_relation.id} is used in relation #{rel.relation.id}." unless rel.nil?
self.changeset_id = new_relation.changeset_id
self.tags = {}
self.members = []
self.visible = false
save_with_history!
end
end
def update_from(new_relation, user)
Relation.transaction do
lock!
check_consistency(self, new_relation, user)
raise OSM::APIPreconditionFailedError, "Cannot update relation #{id}: data or member data is invalid." unless new_relation.preconditions_ok?(members)
self.changeset_id = new_relation.changeset_id
self.changeset = new_relation.changeset
self.tags = new_relation.tags
self.members = new_relation.members
self.visible = true
save_with_history!
end
end
def create_with_history(user)
check_create_consistency(self, user)
raise OSM::APIPreconditionFailedError, "Cannot create relation: data or member data is invalid." unless preconditions_ok?
self.version = 0
self.visible = true
save_with_history!
end
def preconditions_ok?(good_members = [])
raise OSM::APITooManyRelationMembersError.new(id, members.length, Settings.max_number_of_relation_members) if members.length > Settings.max_number_of_relation_members
# These are hastables that store an id in the index of all
# the nodes/way/relations that have already been added.
# If the member is valid and visible then we add it to the
# relevant hash table, with the value true as a cache.
# Thus if you have nodes with the ids of 50 and 1 already in the
# relation, then the hash table nodes would contain:
# => {50=>true, 1=>true}
elements = { :node => {}, :way => {}, :relation => {} }
# pre-set all existing members to good
good_members.each { |m| elements[m[0].downcase.to_sym][m[1]] = true }
members.each do |m|
# find the hash for the element type or die
hash = elements[m[0].downcase.to_sym]
return false unless hash
# unless its in the cache already
next if hash.key? m[1]
# use reflection to look up the appropriate class
model = Kernel.const_get(m[0].capitalize)
# get the element with that ID. and, if found, lock the element to
# ensure it can't be deleted until after the current transaction
# commits.
element = model.lock("for share").find_by(:id => m[1])
# and check that it is OK to use.
raise OSM::APIPreconditionFailedError, "Relation with id #{id} cannot be saved due to #{m[0]} with id #{m[1]}" unless element&.visible? && element&.preconditions_ok?
hash[m[1]] = true
end
true
end
##
# if any members are referenced by placeholder IDs (i.e: negative) then
# this calling this method will fix them using the map from placeholders
# to IDs +id_map+.
def fix_placeholders!(id_map, placeholder_id = nil)
members.map! do |type, id, role|
old_id = id.to_i
if old_id.negative?
new_id = id_map[type.downcase.to_sym][old_id]
raise OSM::APIBadUserInput, "Placeholder #{type} not found for reference #{old_id} in relation #{self.id.nil? ? placeholder_id : self.id}." if new_id.nil?
[type, new_id, role]
else
[type, id, role]
end
end
end
private
def save_with_history!
t = Time.now.utc
self.version += 1
self.timestamp = t
Relation.transaction do
# have to be a little bit clever here - to detect if any tags
# changed then we have to monitor their before and after state.
tags_changed = false
# clone the object before saving it so that the original is
# still marked as dirty if we retry the transaction
clone.save!
tags = self.tags.clone
relation_tags.each do |old_tag|
key = old_tag.k
# if we can match the tags we currently have to the list
# of old tags, then we never set the tags_changed flag. but
# if any are different then set the flag and do the DB
# update.
if tags.key? key
tags_changed |= (old_tag.v != tags[key])
# remove from the map, so that we can expect an empty map
# at the end if there are no new tags
tags.delete key
else
# this means a tag was deleted
tags_changed = true
end
end
# if there are left-over tags then they are new and will have to
# be added.
tags_changed |= !tags.empty?
RelationTag.where(:relation_id => id).delete_all
self.tags.each do |k, v|
tag = RelationTag.new
tag.relation_id = id
tag.k = k
tag.v = v
tag.save!
end
# same pattern as before, but this time we're collecting the
# changed members in an array, as the bounding box updates for
# elements are per-element, not blanked on/off like for tags.
changed_members = []
members = self.members.clone
relation_members.each do |old_member|
key = [old_member.member_type, old_member.member_id, old_member.member_role]
i = members.index key
if i.nil?
changed_members << key
else
members.delete_at i
end
end
# any remaining members must be new additions
changed_members += members
# update the members. first delete all the old members, as the new
# members may be in a different order and i don't feel like implementing
# a longest common subsequence algorithm to optimise this.
members = self.members
RelationMember.where(:relation_id => id).delete_all
members.each_with_index do |m, i|
mem = RelationMember.new
mem.relation_id = id
mem.sequence_id = i
mem.member_type = m[0]
mem.member_id = m[1]
mem.member_role = m[2]
mem.save!
end
old_relation = OldRelation.from_relation(self)
old_relation.timestamp = t
old_relation.save_with_dependencies!
# update the bbox of the changeset and save it too.
# discussion on the mailing list gave the following definition for
# the bounding box update procedure of a relation:
#
# adding or removing nodes or ways from a relation causes them to be
# added to the changeset bounding box. adding a relation member or
# changing tag values causes all node and way members to be added to the
# bounding box. this is similar to how the map call does things and is
# reasonable on the assumption that adding or removing members doesn't
# materially change the rest of the relation.
any_relations =
changed_members.collect { |type, _id, _role| type == "Relation" }
.inject(false) { |acc, elem| acc || elem }
# if the relation is being deleted tags_changed will be true and members empty
# so we need to use changed_members to create a correct bounding box
update_members = if visible && (tags_changed || any_relations)
# add all non-relation bounding boxes to the changeset
# FIXME: check for tag changes along with element deletions and
# make sure that the deleted element's bounding box is hit.
self.members
else
changed_members
end
update_members.each do |type, id, _role|
update_changeset_element(type, id) if type != "Relation"
end
# tell the changeset we updated one element only
changeset.add_changes! 1
# save the (maybe updated) changeset bounding box
changeset.save!
end
end
end