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

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

diff --git a/app/models/node.rb b/app/models/node.rb
index f2fe341aecc2bf6fcc3b82701201fb11eb48f03b..01b0f220e6ed565a1db167ea265d39f85b670ab2 100644 (file)
--- a/app/models/node.rb
+++ b/app/models/node.rb
@@ -64,29 +64,31 @@ class Node < ActiveRecord::Base
   # Read in xml as text and return it's Node object representation
   def self.from_xml(xml, create=false)
     begin
   # Read in xml as text and return it's Node object representation
   def self.from_xml(xml, create=false)
     begin

-      p = XML::Parser.new
-      p.string = xml
+      p = XML::Parser.string(xml)

       doc = p.parse
 
       doc.find('//osm/node').each do |pt|
         return Node.from_xml_node(pt, create)
       end
       doc = p.parse
 
       doc.find('//osm/node').each do |pt|
         return Node.from_xml_node(pt, create)
       end

-    rescue
-      return nil
+    rescue LibXML::XML::Error, ArgumentError => ex
+      raise OSM::APIBadXMLError.new("node", xml, ex.message)

     end
   end
 
   def self.from_xml_node(pt, create=false)
     node = Node.new
     
     end
   end
 
   def self.from_xml_node(pt, create=false)
     node = Node.new
     

+    raise OSM::APIBadXMLError.new("node", pt, "lat missing") if pt['lat'].nil?
+    raise OSM::APIBadXMLError.new("node", pt, "lon missing") if pt['lon'].nil?

     node.lat = pt['lat'].to_f
     node.lon = pt['lon'].to_f
     node.lat = pt['lat'].to_f
     node.lon = pt['lon'].to_f

+    raise OSM::APIBadXMLError.new("node", pt, "changeset id missing") if pt['changeset'].nil?

     node.changeset_id = pt['changeset'].to_i
 
     node.changeset_id = pt['changeset'].to_i
 

-    return nil unless node.in_world?
+    raise OSM::APIBadUserInput.new("The node is outside this world") unless node.in_world?

 
     # version must be present unless creating
 
     # version must be present unless creating

-    return nil unless create or not pt['version'].nil?
+    raise OSM::APIBadXMLError.new("node", pt, "Version is required when updating") unless create or not pt['version'].nil?

     node.version = create ? 0 : pt['version'].to_i
 
     unless create
     node.version = create ? 0 : pt['version'].to_i
 
     unless create


@@ -97,15 +99,10 @@ class Node < ActiveRecord::Base
 
     # visible if it says it is, or as the default if the attribute
     # is missing.
 
     # visible if it says it is, or as the default if the attribute
     # is missing.

-    node.visible = pt['visible'].nil? or pt['visible'] == 'true'
+    # Don't need to set the visibility, when it is set explicitly in the create/update/delete
+    #node.visible = pt['visible'].nil? or pt['visible'] == 'true'

 
 

-    if create
-      node.timestamp = Time.now
-    else
-      if pt['timestamp']
-        node.timestamp = Time.parse(pt['timestamp'])
-      end
-    end
+    # We don't care about the time, as it is explicitly set on create/update/delete

 
     tags = []
 
 
     tags = []
 


@@ -117,81 +114,65 @@ class Node < ActiveRecord::Base
   end
 
   ##
   end
 
   ##

-  # the bounding box around a node
+  # the bounding box around a node, which is used for determining the changeset's
+  # bounding box

   def bbox
     [ longitude, latitude, longitude, latitude ]
   end
 
   def bbox
     [ longitude, latitude, longitude, latitude ]
   end
 

-  def save_with_history!
-    t = Time.now
-    Node.transaction do
-      self.version += 1
-      self.timestamp = t
-      self.save!
-
-      # Create a NodeTag
-      tags = self.tags
-      NodeTag.delete_all(['id = ?', self.id])
-      tags.each do |k,v|
-        tag = NodeTag.new
-        tag.k = k 
-        tag.v = v 
-        tag.id = self.id
-        tag.save!
-      end 
-
-      # Create an OldNode
-      old_node = OldNode.from_node(self)
-      old_node.timestamp = t
-      old_node.save_with_dependencies!
-
-      # tell the changeset we updated one element only
-      changeset.add_changes! 1
-
-      # save the changeset in case of bounding box updates
-      changeset.save!
-    end
-  end
-

   # Should probably be renamed delete_from to come in line with update
   def delete_with_history!(new_node, user)
   # Should probably be renamed delete_from to come in line with update
   def delete_with_history!(new_node, user)

-    if self.visible
+    unless self.visible
+      raise OSM::APIAlreadyDeletedError.new("node", new_node.id)
+    end
+
+    # 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)
       check_consistency(self, new_node, user)

-      if WayNode.find(:first, :joins => "INNER JOIN current_ways ON current_ways.id = current_way_nodes.id", :conditions => [ "current_ways.visible = ? AND current_way_nodes.node_id = ?", true, 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 = ? AND member_type='node' and member_id=? ", true, self.id])
-        raise OSM::APIPreconditionFailedError.new
-      else
-        self.changeset_id = new_node.changeset_id
-        self.visible = false
-
-        # update the changeset with the deleted position
-        changeset.update_bbox!(bbox)
-
-        save_with_history!
-      end
-    else
-      raise OSM::APIAlreadyDeletedError.new
+      way = WayNode.find(:first, :joins => :way, 
+                         :conditions => [ "current_ways.visible = ? AND current_way_nodes.node_id = ?", true, self.id ])
+      raise OSM::APIPreconditionFailedError.new("Node #{self.id} is still used by way #{way.way.id}.") unless way.nil?
+      
+      rel = RelationMember.find(:first, :joins => :relation, 
+                                :conditions => [ "visible = ? AND member_type='Node' and member_id=? ", true, self.id])
+      raise OSM::APIPreconditionFailedError.new("Node #{self.id} is still used by relation #{rel.relation.id}.") unless rel.nil?
+
+      self.changeset_id = new_node.changeset_id
+      self.visible = false
+      
+      # update the changeset with the deleted position
+      changeset.update_bbox!(bbox)
+      
+      save_with_history!

     end
   end
 
   def update_from(new_node, user)
     end
   end
 
   def update_from(new_node, user)

-    check_consistency(self, new_node, user)
-
-    # update changeset with *old* position first
-    changeset.update_bbox!(bbox);
-
-    # FIXME logic needs to be double checked
-    self.changeset_id = new_node.changeset_id
-    self.latitude = new_node.latitude 
-    self.longitude = new_node.longitude
-    self.tags = new_node.tags
-    self.visible = true
-
-    # update changeset with *new* position
-    changeset.update_bbox!(bbox);
-
-    save_with_history!
+    Node.transaction do
+      self.lock!
+      check_consistency(self, new_node, user)
+      
+      # update changeset first
+      self.changeset_id = new_node.changeset_id
+      self.changeset = new_node.changeset
+      
+      # update changeset bbox with *old* position first
+      changeset.update_bbox!(bbox);
+      
+      # FIXME logic needs to be double checked
+      self.latitude = new_node.latitude 
+      self.longitude = new_node.longitude
+      self.tags = new_node.tags
+      self.visible = true
+      
+      # update changeset bbox with *new* position
+      changeset.update_bbox!(bbox);
+      
+      save_with_history!
+    end

   end
   
   def create_with_history(user)
   end
   
   def create_with_history(user)


@@ -211,27 +192,33 @@ class Node < ActiveRecord::Base
     return doc
   end
 
     return doc
   end
 

-  def to_xml_node(user_display_name_cache = nil)
+  def to_xml_node(changeset_cache = {}, user_display_name_cache = {})

     el1 = XML::Node.new 'node'
     el1['id'] = self.id.to_s
     el1['lat'] = self.lat.to_s
     el1['lon'] = self.lon.to_s
     el1['version'] = self.version.to_s
     el1['changeset'] = self.changeset_id.to_s
     el1 = XML::Node.new 'node'
     el1['id'] = self.id.to_s
     el1['lat'] = self.lat.to_s
     el1['lon'] = self.lon.to_s
     el1['version'] = self.version.to_s
     el1['changeset'] = self.changeset_id.to_s

-    
-    user_display_name_cache = {} if user_display_name_cache.nil?

 
 

-    if user_display_name_cache and user_display_name_cache.key?(self.changeset.user_id)
+    if changeset_cache.key?(self.changeset_id)
+      # use the cache if available
+    else
+      changeset_cache[self.changeset_id] = self.changeset.user_id
+    end
+
+    user_id = changeset_cache[self.changeset_id]
+
+    if user_display_name_cache.key?(user_id)

       # use the cache if available
     elsif self.changeset.user.data_public?
       # use the cache if available
     elsif self.changeset.user.data_public?

-      user_display_name_cache[self.changeset.user_id] = self.changeset.user.display_name
+      user_display_name_cache[user_id] = self.changeset.user.display_name

     else
     else

-      user_display_name_cache[self.changeset.user_id] = nil
+      user_display_name_cache[user_id] = nil

     end
 
     end
 

-    if not user_display_name_cache[self.changeset.user_id].nil?
-      el1['user'] = user_display_name_cache[self.changeset.user_id]
-      el1['uid'] = self.changeset.user_id.to_s
+    if not user_display_name_cache[user_id].nil?
+      el1['user'] = user_display_name_cache[user_id]
+      el1['uid'] = user_id.to_s

     end
 
     self.tags.each do |k,v|
     end
 
     self.tags.each do |k,v|


@@ -269,7 +256,7 @@ class Node < ActiveRecord::Base
 
     # duplicate tags are now forbidden, so we can't allow values
     # in the hash to be overwritten.
 
     # duplicate tags are now forbidden, so we can't allow values
     # in the hash to be overwritten.

-    raise OSM::APIDuplicateTagsError.new if @tags.include? k
+    raise OSM::APIDuplicateTagsError.new("node", self.id, k) if @tags.include? k

 
     @tags[k] = v
   end
 
     @tags[k] = v
   end


@@ -284,8 +271,41 @@ class Node < ActiveRecord::Base
   ##
   # dummy method to make the interfaces of node, way and relation
   # more consistent.
   ##
   # dummy method to make the interfaces of node, way and relation
   # more consistent.

-  def fix_placeholders!(id_map)
+  def fix_placeholders!(id_map, placeholder_id = nil)

     # nodes don't refer to anything, so there is nothing to do here
   end
     # nodes don't refer to anything, so there is nothing to do here
   end

+  
+  private
+
+  def save_with_history!
+    t = Time.now.getutc
+    Node.transaction do
+      self.version += 1
+      self.timestamp = t
+      self.save!
+
+      # Create a NodeTag
+      tags = self.tags
+      NodeTag.delete_all(['id = ?', self.id])
+      tags.each do |k,v|
+        tag = NodeTag.new
+        tag.k = k 
+        tag.v = v 
+        tag.id = self.id
+        tag.save!
+      end 

 
 

+      # Create an OldNode
+      old_node = OldNode.from_node(self)
+      old_node.timestamp = t
+      old_node.save_with_dependencies!
+
+      # tell the changeset we updated one element only
+      changeset.add_changes! 1
+
+      # save the changeset in case of bounding box updates
+      changeset.save!
+    end
+  end
+  

 end
 end