# in OsmChange format. All diffs must be limited to a single changeset
# given in +changeset+.
def initialize(data, changeset)
- @reader = XML::Reader.new data
+ @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
##
# Reads the next element from the XML document. Checks the return value
# and throws an exception if an error occurred.
def read_or_die
- # NOTE: XML::Reader#read returns 0 for EOF and -1 for error.
- # we allow an EOF because we are expecting this to always happen
- # at the end of a document.
- if @reader.read < 0
- raise APIBadUserInput.new("Unexpected end of XML document.")
+ # NOTE: XML::Reader#read returns false for EOF and raises an
+ # exception if an error occurs.
+ begin
+ @reader.read
+ rescue LibXML::XML::Error => ex
+ raise OSM::APIBadXMLError.new("changeset", xml, ex.message)
end
end
# read the first element
read_or_die
- begin
+ while @reader.node_type != 15 do # end element
# because we read elements in DOM-style to reuse their DOM
# parsing code, we don't always read an element on each pass
# 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 while @reader.node_type != 15 # end element
+ end
end
read_or_die
end
# 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 "Unexpected element type #{model_name}, " +
- "expected node, way, relation." if model.nil?
- yield model, @reader.expand
+ raise OSM::APIBadUserInput.new("Unexpected element type #{model_name}, " +
+ "expected node, way or relation.") if model.nil?
+ # 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
# 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.
# some elements may have placeholders for other elements in the
# diff, so we must fix these before saving the element.
- new.fix_placeholders!(ids)
+ new.fix_placeholders!(ids, placeholder_id)
# create element given user
new.create_with_history(@changeset.user)
# if the ID is a placeholder then map it to the real ID
model_sym = model.to_s.downcase.to_sym
- is_placeholder = ids[model_sym].include? new.id
- id = is_placeholder ? ids[model_sym][new.id] : new.id
+ client_id = new.id
+ is_placeholder = ids[model_sym].include? client_id
+ id = is_placeholder ? ids[model_sym][client_id] : client_id
# and the old one from the database
old = model.find(id)
+ # translate any placeholder IDs to their true IDs.
new.fix_placeholders!(ids)
+ new.id = id
+
old.update_from(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
+ xml_result["old_id"] = client_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!
# delete action. this takes a payload in API 0.6, so we need to do
# most of the same checks that are done for the modify.
with_model do |model, xml|
- new = model.from_xml_node(xml, false)
- check(model, xml, new)
+ # 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 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
- is_placeholder = ids[model_sym].include? new.id
- id = is_placeholder ? ids[model_sym][new.id] : new.id
+ is_placeholder = ids[model_sym].include? new_id
+ id = is_placeholder ? ids[model_sym][new_id] : new_id
+ # build the "new" element by modifying the existing one
+ new = model.find(id)
+ new.changeset_id = xml['changeset'].to_i
+ new.version = xml['version'].to_i
+ check(model, xml, new)
+
+ # fetch the matching old element from the DB
old = model.find(id)
# 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
+ 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
projects / rails.git / blobdiff