Added locking around update and delete methods on main API objects. This should remov...

[rails.git] / app / models / relation.rb

diff --git a/app/models/relation.rb b/app/models/relation.rb
index 787c167197abf5add81f61df51c631f42047bbfe..32dab6254532278a8d9a182717907aa26cb974b4 100644 (file)
--- a/app/models/relation.rb
+++ b/app/models/relation.rb
@@ -87,7 +87,7 @@ class Relation < ActiveRecord::Base
     return doc
   end
 
-  def to_xml_node(changeset_cache = {}, user_display_name_cache = {})
+  def to_xml_node(visible_members = nil, changeset_cache = {}, user_display_name_cache = {})
     el1 = XML::Node.new 'relation'
     el1['id'] = self.id.to_s
     el1['visible'] = self.visible.to_s
@@ -118,17 +118,17 @@ class Relation < ActiveRecord::Base
 
     self.relation_members.each do |member|
       p=0
-      #if visible_members
-      #  # if there is a list of visible members then use that to weed out deleted segments
-      #  if visible_members[member.member_type][member.member_id]
-      #    p=1
-      #  end
-      #else
+      if visible_members
+        # if there is a list of visible members then use that to weed out deleted segments
+        if visible_members[member.member_type][member.member_id]
+          p=1
+        end
+      else
         # otherwise, manually go to the db to check things
         if member.member.visible?
           p=1
         end
-      #end
+      end
       if p
         e = XML::Node.new 'member'
         e['type'] = member.member_type.downcase
@@ -240,6 +240,7 @@ class Relation < ActiveRecord::Base
     # provide repeatable reads for the used-by checks. this means it
     # shouldn't be possible to get race conditions.
     Relation.transaction do
+      self.lock!
       check_consistency(self, new_relation, user)
       # This will check to see if this relation is used by another relation
       rel = RelationMember.find(:first, :joins => :relation, 
@@ -255,16 +256,19 @@ class Relation < ActiveRecord::Base
   end
 
   def update_from(new_relation, user)
-    check_consistency(self, new_relation, user)
-    unless new_relation.preconditions_ok?
-      raise OSM::APIPreconditionFailedError.new("Cannot update relation #{self.id}: data or member data is invalid.")
+    Relation.transaction do
+      self.lock!
+      check_consistency(self, new_relation, user)
+      unless new_relation.preconditions_ok?(self.members)
+        raise OSM::APIPreconditionFailedError.new("Cannot update relation #{self.id}: data or member data is invalid.")
+      end
+      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
-    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
   
   def create_with_history(user)
@@ -277,7 +281,7 @@ class Relation < ActiveRecord::Base
     save_with_history!
   end
 
-  def preconditions_ok?
+  def preconditions_ok?(good_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 
@@ -286,6 +290,10 @@ class Relation < ActiveRecord::Base
     # relation, then the hash table nodes would contain:
     # => {50=>true, 1=>true}
     elements = { :node => Hash.new, :way => Hash.new, :relation => Hash.new }
+
+    # pre-set all existing members to good
+    good_members.each { |m| elements[m[0].downcase.to_sym][m[1]] = true }
+
     self.members.each do |m|
       # find the hash for the element type or die
       hash = elements[m[0].downcase.to_sym] or return false
@@ -294,20 +302,17 @@ class Relation < ActiveRecord::Base
         # use reflection to look up the appropriate class
         model = Kernel.const_get(m[0].capitalize)
         # get the element with that ID
-        element = model.find(m[1])
+        element = model.find(:first, :conditions =>["id = ?", m[1]])
 
         # and check that it is OK to use.
         unless element and element.visible? and element.preconditions_ok?
-          raise OSM::APIPreconditionFailedError.new("Relation with id #{self.id} cannot be saved due to #{m[0]} with id #{element.id}")
-          return false
+          raise OSM::APIPreconditionFailedError.new("Relation with id #{self.id} cannot be saved due to #{m[0]} with id #{m[1]}")
         end
         hash[m[1]] = true
       end
     end
 
     return true
-  rescue
-    return false
   end
 
   # Temporary method to match interface to nodes