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

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

diff --git a/app/models/way.rb b/app/models/way.rb
index 64b3991336c7d9bf21664f4c0979405550a805ab..4f988dc9ddfc2b8d13ca28d0553693f499633f5e 100644 (file)
--- a/app/models/way.rb
+++ b/app/models/way.rb
@@ -204,17 +204,20 @@ class Way < ActiveRecord::Base
   end
 
   def update_from(new_way, user)
-    check_consistency(self, new_way, user)
-    unless new_way.preconditions_ok?
-      raise OSM::APIPreconditionFailedError.new("Cannot update way #{self.id}: data is invalid.")
+    Way.transaction do
+      self.lock!
+      check_consistency(self, new_way, user)
+      unless new_way.preconditions_ok?(self.nds)
+        raise OSM::APIPreconditionFailedError.new("Cannot update way #{self.id}: data is invalid.")
+      end
+      
+      self.changeset_id = new_way.changeset_id
+      self.changeset = new_way.changeset
+      self.tags = new_way.tags
+      self.nds = new_way.nds
+      self.visible = true
+      save_with_history!
     end
-
-    self.changeset_id = new_way.changeset_id
-    self.changeset = new_way.changeset
-    self.tags = new_way.tags
-    self.nds = new_way.nds
-    self.visible = true
-    save_with_history!
   end
 
   def create_with_history(user)
@@ -227,17 +230,25 @@ class Way < ActiveRecord::Base
     save_with_history!
   end
 
-  def preconditions_ok?
+  def preconditions_ok?(old_nodes = [])
     return false if self.nds.empty?
     if self.nds.length > APP_CONFIG['max_number_of_way_nodes']
       raise OSM::APITooManyWayNodesError.new(self.nds.length, APP_CONFIG['max_number_of_way_nodes'])
     end
-    self.nds.each do |n|
-      node = Node.find(:first, :conditions => ["id = ?", n])
-      unless node and node.visible
-        raise OSM::APIPreconditionFailedError.new("The node with id #{n} either does not exist, or is not visible")
+
+    # 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.find(:all, :conditions => { :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
 
@@ -250,19 +261,19 @@ class Way < ActiveRecord::Base
     # 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)
-      if RelationMember.find(:first, :joins => :relation,
+      rel = RelationMember.find(:first, :joins => :relation,
                              :conditions => [ "visible = ? AND member_type='Way' and member_id=? ", true, self.id])
-        raise OSM::APIPreconditionFailedError.new("You need to make sure that the way with id: #{self.id} is not a member of a relation.")
-      else
-        self.changeset_id = new_way.changeset_id
-        self.changeset = new_way.changeset
-
-        self.tags = []
-        self.nds = []
-        self.visible = false
-        save_with_history!
-      end
+      raise OSM::APIPreconditionFailedError.new("Way #{self.id} still used by relation #{rel.relation.id}.") if rel
+      
+      self.changeset_id = new_way.changeset_id
+      self.changeset = new_way.changeset
+
+      self.tags = []
+      self.nds = []
+      self.visible = false
+      save_with_history!
     end
   end