app/models/relation.rb

   1 class Relation < ActiveRecord::Base
   2   require 'xml/libxml'
   3
   4   include ConsistencyValidations
   5
   6   set_table_name 'current_relations'
   7
   8   belongs_to :changeset
   9
  10   has_many :old_relations, :foreign_key => 'id', :order => 'version'
  11
  12   has_many :relation_members, :foreign_key => 'id'
  13   has_many :relation_tags, :foreign_key => 'id'
  14
  15   has_many :containing_relation_members, :class_name => "RelationMember", :as => :member
  16   has_many :containing_relations, :class_name => "Relation", :through => :containing_relation_members, :source => :relation, :extend => ObjectFinder
  17
  18   def self.from_xml(xml, create=false)
  19     begin
  20       p = XML::Parser.new
  21       p.string = xml
  22       doc = p.parse
  23
  24       doc.find('//osm/relation').each do |pt|
  25         return Relation.from_xml_node(pt, create)
  26       end
  27     rescue
  28       return nil
  29     end
  30   end
  31
  32   def self.from_xml_node(pt, create=false)
  33     relation = Relation.new
  34
  35     if !create and pt['id'] != '0'
  36       relation.id = pt['id'].to_i
  37     end
  38
  39     relation.version = pt['version']
  40     relation.changeset_id = pt['changeset']
  41
  42     if create
  43       relation.timestamp = Time.now
  44       relation.visible = true
  45     else
  46       if pt['timestamp']
  47         relation.timestamp = Time.parse(pt['timestamp'])
  48       end
  49     end
  50
  51     pt.find('tag').each do |tag|
  52       relation.add_tag_keyval(tag['k'], tag['v'])
  53     end
  54
  55     pt.find('member').each do |member|
  56       relation.add_member(member['type'], member['ref'], member['role'])
  57     end
  58
  59     return relation
  60   end
  61
  62   def to_xml
  63     doc = OSM::API.new.get_xml_doc
  64     doc.root << to_xml_node()
  65     return doc
  66   end
  67
  68   def to_xml_node(user_display_name_cache = nil)
  69     el1 = XML::Node.new 'relation'
  70     el1['id'] = self.id.to_s
  71     el1['visible'] = self.visible.to_s
  72     el1['timestamp'] = self.timestamp.xmlschema
  73     el1['version'] = self.version.to_s
  74     el1['changeset'] = self.changeset_id.to_s
  75
  76     user_display_name_cache = {} if user_display_name_cache.nil?
  77
  78     if user_display_name_cache and user_display_name_cache.key?(self.changeset.user_id)
  79       # use the cache if available
  80     elsif self.changeset.user.data_public?
  81       user_display_name_cache[self.changeset.user_id] = self.changeset.user.display_name
  82     else
  83       user_display_name_cache[self.changeset.user_id] = nil
  84     end
  85
  86     el1['user'] = user_display_name_cache[self.changeset.user_id] unless user_display_name_cache[self.changeset.user_id].nil?
  87
  88     self.relation_members.each do |member|
  89       p=0
  90       #if visible_members
  91       #  # if there is a list of visible members then use that to weed out deleted segments
  92       #  if visible_members[member.member_type][member.member_id]
  93       #    p=1
  94       #  end
  95       #else
  96         # otherwise, manually go to the db to check things
  97         if member.member.visible?
  98           p=1
  99         end
 100       #end
 101       if p
 102         e = XML::Node.new 'member'
 103         e['type'] = member.member_type
 104         e['ref'] = member.member_id.to_s
 105         e['role'] = member.member_role
 106         el1 << e
 107        end
 108     end
 109
 110     self.relation_tags.each do |tag|
 111       e = XML::Node.new 'tag'
 112       e['k'] = tag.k
 113       e['v'] = tag.v
 114       el1 << e
 115     end
 116     return el1
 117   end
 118
 119   def self.find_for_nodes(ids, options = {})
 120     if ids.empty?
 121       return []
 122     else
 123       self.with_scope(:find => { :joins => "INNER JOIN current_relation_members ON current_relation_members.id = current_relations.id", :conditions => "current_relation_members.member_type = 'node' AND current_relation_members.member_id IN (#{ids.join(',')})" }) do
 124         return self.find(:all, options)
 125       end
 126     end
 127   end
 128
 129   def self.find_for_ways(ids, options = {})
 130     if ids.empty?
 131       return []
 132     else
 133       self.with_scope(:find => { :joins => "INNER JOIN current_relation_members ON current_relation_members.id = current_relations.id", :conditions => "current_relation_members.member_type = 'way' AND current_relation_members.member_id IN (#{ids.join(',')})" }) do
 134         return self.find(:all, options)
 135       end
 136     end
 137   end
 138
 139   def self.find_for_relations(ids, options = {})
 140     if ids.empty?
 141       return []
 142     else
 143       self.with_scope(:find => { :joins => "INNER JOIN current_relation_members ON current_relation_members.id = current_relations.id", :conditions => "current_relation_members.member_type = 'relation' AND current_relation_members.member_id IN (#{ids.join(',')})" }) do
 144         return self.find(:all, options)
 145       end
 146     end
 147   end
 148
 149   # FIXME is this really needed?
 150   def members
 151     unless @members
 152       @members = Array.new
 153       self.relation_members.each do |member|
 154         @members += [[member.member_type,member.member_id,member.member_role]]
 155       end
 156     end
 157     @members
 158   end
 159
 160   def tags
 161     unless @tags
 162       @tags = Hash.new
 163       self.relation_tags.each do |tag|
 164         @tags[tag.k] = tag.v
 165       end
 166     end
 167     @tags
 168   end
 169
 170   def members=(m)
 171     @members = m
 172   end
 173
 174   def tags=(t)
 175     @tags = t
 176   end
 177
 178   def add_member(type,id,role)
 179     @members = Array.new unless @members
 180     @members += [[type,id,role]]
 181   end
 182
 183   def add_tag_keyval(k, v)
 184     @tags = Hash.new unless @tags
 185
 186     # duplicate tags are now forbidden, so we can't allow values
 187     # in the hash to be overwritten.
 188     raise OSM::APIDuplicateTagsError.new if @tags.include? k
 189
 190     @tags[k] = v
 191   end
 192
 193   def save_with_history!
 194     Relation.transaction do
 195       t = Time.now
 196       self.version += 1
 197       self.timestamp = t
 198       self.save!
 199
 200       tags = self.tags
 201       RelationTag.delete_all(['id = ?', self.id])
 202       tags.each do |k,v|
 203         tag = RelationTag.new
 204         tag.k = k
 205         tag.v = v
 206         tag.id = self.id
 207         tag.save!
 208       end
 209
 210       members = self.members
 211       RelationMember.delete_all(['id = ?', self.id])
 212       members.each do |n|
 213         mem = RelationMember.new
 214         mem.id = self.id
 215         mem.member_type = n[0];
 216         mem.member_id = n[1];
 217         mem.member_role = n[2];
 218         mem.save!
 219       end
 220
 221       old_relation = OldRelation.from_relation(self)
 222       old_relation.timestamp = t
 223       old_relation.save_with_dependencies!
 224
 225       # update the bbox of the changeset and save it too.
 226       # FIXME: what is the bounding box of a relation?
 227     end
 228   end
 229
 230   def delete_with_history!(new_relation, user)
 231     if self.visible
 232       check_consistency(self, new_relation, user)
 233       if RelationMember.find(:first, :joins => "INNER JOIN current_relations ON current_relations.id=current_relation_members.id", :conditions => [ "visible = 1 AND member_type='relation' and member_id=? ", self.id ])
 234         raise OSM::APIPreconditionFailedError.new
 235       else
 236         self.changeset_id = new_relation.changeset_id
 237         self.tags = []
 238         self.members = []
 239         self.visible = false
 240         save_with_history!
 241       end
 242     else
 243       raise OSM::APIAlreadyDeletedError.new
 244     end
 245   end
 246
 247   def update_from(new_relation, user)
 248     check_consistency(self, new_relation, user)
 249     if !new_relation.preconditions_ok?
 250       raise OSM::APIPreconditionFailedError.new
 251     end
 252     self.changeset_id = new_relation.changeset_id
 253     self.tags = new_relation.tags
 254     self.members = new_relation.members
 255     self.visible = true
 256     save_with_history!
 257   end
 258
 259   def create_with_history(user)
 260     check_create_consistency(self, user)
 261     if !self.preconditions_ok?
 262       raise OSM::APIPreconditionFailedError.new
 263     end
 264     self.version = 0
 265     self.visible = true
 266     save_with_history!
 267   end
 268
 269   def preconditions_ok?
 270     # These are hastables that store an id in the index of all
 271     # the nodes/way/relations that have already been added.
 272     # Once we know the id of the node/way/relation exists
 273     # we check to see if it is already existing in the hashtable
 274     # if it does, then we return false. Otherwise
 275     # we add it to the relevant hash table, with the value true..
 276     # Thus if you have nodes with the ids of 50 and 1 already in the
 277     # relation, then the hash table nodes would contain:
 278     # => {50=>true, 1=>true}
 279     nodes = Hash.new
 280     ways = Hash.new
 281     relations = Hash.new
 282     self.members.each do |m|
 283       if (m[0] == "node")
 284         n = Node.find(:first, :conditions => ["id = ?", m[1]])
 285         unless n and n.visible
 286           return false
 287         end
 288         if nodes[m[1]]
 289           return false
 290         else
 291           nodes[m[1]] = true
 292         end
 293       elsif (m[0] == "way")
 294         w = Way.find(:first, :conditions => ["id = ?", m[1]])
 295         unless w and w.visible and w.preconditions_ok?
 296           return false
 297         end
 298         if ways[m[1]]
 299           return false
 300         else
 301           ways[m[1]] = true
 302         end
 303       elsif (m[0] == "relation")
 304         e = Relation.find(:first, :conditions => ["id = ?", m[1]])
 305         unless e and e.visible and e.preconditions_ok?
 306           return false
 307         end
 308         if relations[m[1]]
 309           return false
 310         else
 311           relations[m[1]] = true
 312         end
 313       else
 314         return false
 315       end
 316     end
 317     return true
 318   rescue
 319     return false
 320   end
 321
 322   # Temporary method to match interface to nodes
 323   def tags_as_hash
 324     return self.tags
 325   end
 326
 327   ##
 328   # if any members are referenced by placeholder IDs (i.e: negative) then
 329   # this calling this method will fix them using the map from placeholders
 330   # to IDs +id_map+.
 331   def fix_placeholders!(id_map)
 332     self.members.map! do |type, id, role|
 333       old_id = id.to_i
 334       if old_id < 0
 335         new_id = id_map[type.to_sym][old_id]
 336         raise "invalid placeholder" if new_id.nil?
 337         [type, new_id, role]
 338       else
 339         [type, id, role]
 340       end
 341     end
 342   end
 343
 344 end