Bundle Latest REXML

Sam Ruby has been doing a bang-up job fixing the bugs in REXML.
Who knows when these improvements will trickle down to vendor distributions of Ruby.
In the meantime, let's bundle the latest version of REXML with Instiki.
We check the version number of the bundled REXML against that of the System REXML, and use whichever is later.

vendor/plugins/rexml/lib/rexml/parsers/treeparser.rb

@@ -0,0 +1,100 @@
+require 'rexml/validation/validationexception'
+require 'rexml/undefinednamespaceexception'
+
+module REXML
+  module Parsers
+    class TreeParser
+      def initialize( source, build_context = Document.new )
+        @build_context = build_context
+        @parser = Parsers::BaseParser.new( source )
+      end
+
+      def add_listener( listener )
+        @parser.add_listener( listener )
+      end
+
+      def parse
+        tag_stack = []
+        in_doctype = false
+        entities = nil
+        begin
+          while true
+            event = @parser.pull
+            #STDERR.puts "TREEPARSER GOT #{event.inspect}"
+            case event[0]
+            when :end_document
+              unless tag_stack.empty?
+                #raise ParseException.new("No close tag for #{tag_stack.inspect}")
+                raise ParseException.new("No close tag for #{@build_context.xpath}")
+              end
+              return
+            when :start_element
+              tag_stack.push(event[1])
+              el = @build_context = @build_context.add_element( event[1] )
+              event[2].each do |key, value|
+                el.attributes[key]=Attribute.new(key,value,self)
+              end
+            when :end_element
+              tag_stack.pop
+              @build_context = @build_context.parent
+            when :text
+              if not in_doctype
+                if @build_context[-1].instance_of? Text
+                  @build_context[-1] << event[1]
+                else
+                  @build_context.add( 
+                    Text.new(event[1], @build_context.whitespace, nil, true) 
+                  ) unless (
+                    @build_context.ignore_whitespace_nodes and
+                    event[1].strip.size==0
+                  )
+                end
+              end
+            when :comment
+              c = Comment.new( event[1] )
+              @build_context.add( c )
+            when :cdata
+              c = CData.new( event[1] )
+              @build_context.add( c )
+            when :processing_instruction
+              @build_context.add( Instruction.new( event[1], event[2] ) )
+            when :end_doctype
+              in_doctype = false
+              entities.each { |k,v| entities[k] = @build_context.entities[k].value }
+              @build_context = @build_context.parent
+            when :start_doctype
+              doctype = DocType.new( event[1..-1], @build_context )
+              @build_context = doctype
+              entities = {}
+              in_doctype = true
+            when :attlistdecl
+              n = AttlistDecl.new( event[1..-1] )
+              @build_context.add( n )
+            when :externalentity
+              n = ExternalEntity.new( event[1] )
+              @build_context.add( n )
+            when :elementdecl
+              n = ElementDecl.new( event[1] )
+              @build_context.add(n)
+            when :entitydecl
+              entities[ event[1] ] = event[2] unless event[2] =~ /PUBLIC|SYSTEM/
+              @build_context.add(Entity.new(event))
+            when :notationdecl
+              n = NotationDecl.new( *event[1..-1] )
+              @build_context.add( n )
+            when :xmldecl
+              x = XMLDecl.new( event[1], event[2], event[3] )
+              @build_context.add( x )
+            end
+          end
+        rescue REXML::Validation::ValidationException
+          raise
+        rescue REXML::UndefinedNamespaceException
+          raise
+        rescue
+          raise ParseException.new( $!.message, @parser.source, @parser, $! )
+        end
+      end
+    end
+  end
+end