Simplify a number of object model methods

[rails.git] / lib / diff_reader.rb

diff --git a/lib/diff_reader.rb b/lib/diff_reader.rb
index 0b159315830e25a6eb6c56c98c2295fbcac3ee36..de2da3c6bfd3c55c705918c8e79e2e3b27a3226b 100644 (file)
--- a/lib/diff_reader.rb
+++ b/lib/diff_reader.rb
@@ -20,6 +20,10 @@ class DiffReader
   def initialize(data, changeset)
     @reader = XML::Reader.string(data)
     @changeset = changeset
+    # document that's (re-)used to handle elements expanded out of the
+    # diff processing stream.
+    @doc = XML::Document.new
+    @doc.root = XML::Node.new("osm")
   end
 
   ##
@@ -54,7 +58,18 @@ class DiffReader
         # as the call to @reader.next in the innermost loop will take
         # care of that for us.
         if @reader.node_type == 1 # element
-          yield @reader.name
+          name = @reader.name
+          attributes =  {}
+
+          if @reader.has_attributes?
+            while @reader.move_to_next_attribute == 1
+              attributes[@reader.name] = @reader.value
+            end
+
+            @reader.move_to_element
+          end
+
+          yield name, attributes
         else
           read_or_die
         end
@@ -70,12 +85,25 @@ class DiffReader
   # elements, it would be better to DRY and do this in a block. This
   # could also help with error handling...?
   def with_model
-    with_element do |model_name|
+    with_element do |model_name,model_attributes|
       model = MODELS[model_name]
       raise OSM::APIBadUserInput.new("Unexpected element type #{model_name}, " +
                                      "expected node, way or relation.") if model.nil?
-      yield model, @reader.expand
+      # new in libxml-ruby >= 2, expand returns an element not associated 
+      # with a document. this means that there's no encoding parameter,
+      # which means basically nothing works.
+      expanded = @reader.expand
+
+      # create a new, empty document to hold this expanded node
+      new_node = @doc.import(expanded)
+      @doc.root << new_node
+
+      yield model, new_node
       @reader.next
+
+      # remove element from doc - it will be garbage collected and the
+      # rest of the document is re-used in the next iteration.
+      @doc.root.child.remove!
     end
   end
 
@@ -104,13 +132,13 @@ class DiffReader
 
     # take the first element and check that it is an osmChange element
     @reader.read
-    raise APIBadUserInput.new("Document element should be 'osmChange'.") if @reader.name != 'osmChange'
+    raise OSM::APIBadUserInput.new("Document element should be 'osmChange'.") if @reader.name != 'osmChange'
 
     result = OSM::API.new.get_xml_doc
     result.root.name = "diffResult"
 
     # loop at the top level, within the <osmChange> element
-    with_element do |action_name|
+    with_element do |action_name,action_attributes|
       if action_name == 'create'
         # create a new element. this code is agnostic of the element type
         # because all the elements support the methods that we're using.
@@ -185,7 +213,7 @@ class DiffReader
           # delete doesn't have to contain a full payload, according to
           # the wiki docs, so we just extract the things we need.
           new_id = xml['id'].to_i
-          raise API::APIBadXMLError.new(model, xml, "ID attribute is required") if new_id.nil?
+          raise OSM::APIBadXMLError.new(model, xml, "ID attribute is required") if new_id.nil?
 
           # if the ID is a placeholder then map it to the real ID
           model_sym = model.to_s.downcase.to_sym
@@ -204,12 +232,23 @@ class DiffReader
           # can a delete have placeholders under any circumstances?
           # if a way is modified, then deleted is that a valid diff?
           new.fix_placeholders!(ids)
-          old.delete_with_history!(new, @changeset.user)
 
           xml_result = XML::Node.new model.to_s.downcase
           # oh, the irony... the "new" element actually contains the "old" ID
           # a better name would have been client/server, but anyway...
           xml_result["old_id"] = new_id.to_s
+
+          if action_attributes["if-unused"]
+            begin
+              old.delete_with_history!(new, @changeset.user)
+            rescue OSM::APIPreconditionFailedError => ex
+              xml_result["new_id"] = old.id.to_s
+              xml_result["new_version"] = old.version.to_s
+            end
+          else
+            old.delete_with_history!(new, @changeset.user)
+          end
+
           result.root << xml_result
         end