Added tests for changeset upload code. Refactored diff reading code and put it into /lib. Changed the route of a changeset upload to explicitly refer to the changeset it applies to (i.e: resource).

app/controllers/changeset_controller.rb

@@ -2,6 +2,7 @@
 
 class ChangesetController < ApplicationController
   require 'xml/libxml'
+  require 'diff_reader'
 
   before_filter :authorize, :only => [:create, :update, :delete, :upload]
   before_filter :check_write_availability, :only => [:create, :update, :delete, :upload]
@@ -70,102 +71,37 @@ class ChangesetController < ApplicationController
     end
   end
 
+  ##
+  # Upload a diff in a single transaction.
+  #
+  # This means that each change within the diff must succeed, i.e: that
+  # each version number mentioned is still current. Otherwise the entire
+  # transaction *must* be rolled back.
+  #
+  # Furthermore, each element in the diff can only reference the current
+  # changeset.
+  #
+  # Returns: ??? the new document? updated diffs?
   def upload
-    unless request.put?
+    # only allow POST requests, as the upload method is most definitely
+    # not idempotent, as several uploads with placeholder IDs will have
+    # different side-effects.
+    # see http://www.w3.org/Protocols/rfc2616/rfc2616-sec9.html#sec9.1.2
+    unless request.post?
       render :nothing => true, :status => :method_not_allowed
       return
     end
 
-    p = XML::Reader.new request.raw_post
-
-    node_ids, way_ids, rel_ids = {}, {}, {}
-    ids = {"node"=>node_ids, "way"=>way_ids, "relation"=>rel_ids}
-
-    models = {"node"=>Node, "way"=>Way, "relation"=>Relation}
-
-    # FIXME shouldn't this be done through the 
-    # res = OSM::API.new.get_xml_doc
-    # as everything else is?
-    res = XML::Document.new
-    res.encoding = 'UTF-8'
-    root = XML::Node.new 'osm'
-    root['version'] = API_VERSION
-    root['creator'] = 'OpenStreetMap.org'
-    res.root = root
-
-    root << XML::Node.new_comment(" Warning: this is a 0.6 result document, " +
-      "not a normal OSM file. ")
-
+    changeset = Changeset.find(params[:id])
+    
+    diff_reader = DiffReader.new(request.raw_post, changeset)
     Changeset.transaction do
-      while p.read == 1
-        break if p.node_type == 15 # end element
-        next unless p.node_type == 1 # element
-
-        case p.name
-        when 'create':
-            while p.read == 1
-            break if p.node_type == 15 # end element
-            next unless p.node_type == 1 # element
-
-            model = models[p.name]
-            next if model.nil?
-
-            elem = XML::Node.new p.name
-            nd = p.expand; p.next
-            osm = model.from_xml_node(nd, true)
-            elem['old_id'] = nd['id']
-
-            case nd.name
-            when 'way':
-                fix_way(osm, node_ids)
-              raise OSM::APIPreconditionFailedError.new if !osm.preconditions_ok?
-            when 'relation':
-                fix_rel(osm, ids)
-              raise OSM::APIPreconditionFailedError.new if !osm.preconditions_ok?
-            end
-
-            create_prim ids[nd.name], osm, nd
-            elem['new_id'] = osm.id.to_s
-            elem['new_version'] = osm.version.to_s
-            root << elem
-          end
-        when 'modify':
-            while p.read == 1
-            break if p.node_type == 15 # end element
-            next unless p.node_type == 1 # element
-
-            model = models[p.name]
-            next if model.nil?
-
-            elem = XML::Node.new p.name
-            new_osm = model.from_xml_node(p.expand); p.next
-            osm = model.find(new_osm.id)
-            osm.update_from new_osm, @user
-            elem['old_id'] = elem['new_id'] = osm.id.to_s
-            elem['new_version'] = osm.version.to_s
-            root << elem
-          end
-        when 'delete':
-            while p.read == 1
-            break if p.node_type == 15 # end element
-            next unless p.node_type == 1 # element
-
-            model = models[p.name]
-            next if model.nil?
-
-            elem = XML::Node.new p.name
-            osm = model.find(p.expand['id']); p.next
-            osm.delete_with_history(@user)
-            elem['old_id'] = elem['new_id'] = osm.id.to_s
-            elem['new_version'] = osm.version.to_s
-            root << elem
-          end
-        end
-      end
+      result = diff_reader.commit
+      render :text => result.to_s, :content_type => "text/xml"
     end
-
-    render :text => res.to_s, :content_type => "text/xml"
-
+    
+  rescue ActiveRecord::RecordNotFound
+    render :nothing => true, :status => :not_found
   rescue OSM::APIError => ex
     render ex.render_opts
   end

app/models/node.rb

@@ -75,20 +75,25 @@ class Node < ActiveRecord::Base
   def self.from_xml_node(pt, create=false)
     node = Node.new
     
-    node.version = pt['version'].to_i
     node.lat = pt['lat'].to_f
     node.lon = pt['lon'].to_f
     node.changeset_id = pt['changeset'].to_i
 
     return nil unless node.in_world?
 
+    # version must be present unless creating
+    return nil unless create or not pt['version'].nil?
+    node.version = pt['version'].to_i
+
     unless create
       if pt['id'] != '0'
         node.id = pt['id'].to_i
       end
     end
 
-    node.visible = pt['visible'] and pt['visible'] == 'true'
+    # visible if it says it is, or as the default if the attribute
+    # is missing.
+    node.visible = pt['visible'].nil? or pt['visible'] == 'true'
 
     if create
       node.timestamp = Time.now
@@ -235,4 +240,11 @@ class Node < ActiveRecord::Base
     @tags[k] = v
   end
 
+  ##
+  # dummy method to make the interfaces of node, way and relation
+  # more consistent.
+  def fix_placeholders!(id_map)
+    # nodes don't refer to anything, so there is nothing to do here
+  end
+
 end

app/models/relation.rb

@@ -320,4 +320,22 @@ class Relation < ActiveRecord::Base
   def tags_as_hash
     return self.tags
   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)
+    self.members.map! do |type, id, role|
+      old_id = id.to_i
+      if old_id < 0
+        new_id = id_map[type.to_sym][old_id]
+        raise "invalid placeholder" if new_id.nil?
+        [type, new_id, role]
+      else
+        [type, id, role]
+      end
+    end
+  end
+
 end

app/models/way.rb

@@ -299,4 +299,21 @@ class Way < ActiveRecord::Base
   def tags_as_hash
     return self.tags
   end
+
+  ##
+  # if any referenced nodes are placeholder IDs (i.e: are negative) then
+  # this calling this method will fix them using the map from placeholders 
+  # to IDs +id_map+. 
+  def fix_placeholders!(id_map)
+    self.nds.map! do |node_id|
+      if node_id < 0
+        new_id = id_map[:node][node_id]
+        raise "invalid placeholder for #{node_id.inspect}: #{new_id.inspect}" if new_id.nil?
+        new_id
+      else
+        node_id
+      end
+    end
+  end
+
 end