X-Git-Url: https://git.openstreetmap.org/rails.git/blobdiff_plain/52395b3cdf4d3cfae95730158edeeccf3d062a8e..34e3e51456774127d43408b7ab65c24f41373f62:/lib/diff_reader.rb

diff --git a/lib/diff_reader.rb b/lib/diff_reader.rb
index 9b3e01b86..40b43c5cd 100644
--- a/lib/diff_reader.rb
+++ b/lib/diff_reader.rb
@@ -7,9 +7,9 @@ class DiffReader
   include ConsistencyValidations
 
   # maps each element type to the model class which handles it
-  MODELS = { 
-    "node"     => Node, 
-    "way"      => Way, 
+  MODELS = {
+    "node"     => Node,
+    "way"      => Way,
     "relation" => Relation
   }
 
@@ -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
 
   ##
@@ -36,7 +40,7 @@ class DiffReader
   end
 
   ##
-  # An element-block mapping for using the LibXML reader interface. 
+  # An element-block mapping for using the LibXML reader interface.
   #
   # Since a lot of LibXML reader usage is boilerplate iteration through
   # elements, it would be better to DRY and do this in a block. This
@@ -54,28 +58,52 @@ 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
-      end 
+      end
     end
     read_or_die
   end
 
   ##
-  # An element-block mapping for using the LibXML reader interface. 
+  # An element-block mapping for using the LibXML reader interface.
   #
   # Since a lot of LibXML reader usage is boilerplate iteration through
   # 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
 
@@ -84,7 +112,7 @@ class DiffReader
   # such as save_ and delete_with_history.
   def check(model, xml, new)
     raise OSM::APIBadXMLError.new(model, xml) if new.nil?
-    unless new.changeset_id == @changeset.id 
+    unless new.changeset_id == @changeset.id
       raise OSM::APIChangesetMismatchError.new(new.changeset_id, @changeset.id)
     end
   end
@@ -94,7 +122,7 @@ class DiffReader
   # is *not* transactional, so code which calls it should ensure that the
   # appropriate transaction block is in place.
   #
-  # On a failure to meet preconditions (e.g: optimistic locking fails) 
+  # On a failure to meet preconditions (e.g: optimistic locking fails)
   # an exception subclassing OSM::APIError will be thrown.
   def commit
 
@@ -110,7 +138,7 @@ class DiffReader
     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.
@@ -134,7 +162,7 @@ class DiffReader
 
           # create element given user
           new.create_with_history(@changeset.user)
-          
+
           # save placeholder => allocated ID map
           ids[model_sym][placeholder_id] = new.id
 
@@ -145,7 +173,7 @@ class DiffReader
           xml_result["new_version"] = new.version.to_s
           result.root << xml_result
         end
-        
+
       elsif action_name == 'modify'
         # modify an existing element. again, this code doesn't directly deal
         # with types, but uses duck typing to handle them transparently.
@@ -171,7 +199,7 @@ class DiffReader
 
           xml_result = XML::Node.new model.to_s.downcase
           xml_result["old_id"] = client_id.to_s
-          xml_result["new_id"] = id.to_s 
+          xml_result["new_id"] = id.to_s
           # version is updated in "old" through the update, so we must not
           # return new.version here but old.version!
           xml_result["new_version"] = old.version.to_s
@@ -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::APIAlreadyDeletedError, 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