These validation files for REXML need to be included in the main branch.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@6596 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

lib/rexml/validation/validation.rb

@@ -0,0 +1,152 @@
+require 'rexml/validation/validationexception'
+
+module REXML
+  module Validation
+    module Validator
+      NILEVENT = [ nil ]
+      def reset
+        @current = @root
+        @root.reset
+        @root.previous = true
+        @attr_stack = []
+        self
+      end
+      def dump
+        puts @root.inspect
+      end
+      def validate( event ) 
+        #puts "Current: #@current"
+        #puts "Event: #{event.inspect}"
+        @attr_stack = [] unless defined? @attr_stack
+        match = @current.next(event)
+        raise ValidationException.new( "Validation error.  Expected: "+
+          @current.expected.join( " or " )+" from #{@current.inspect} "+
+          " but got #{Event.new( event[0], event[1] ).inspect}" ) unless match
+        @current = match
+
+        # Check for attributes
+        case event[0]
+        when :start_element
+          #puts "Checking attributes"
+          @attr_stack << event[2]
+          begin
+            sattr = [:start_attribute, nil]
+            eattr = [:end_attribute]
+            text = [:text, nil]
+            k,v = event[2].find { |k,v| 
+              sattr[1] = k
+              #puts "Looking for #{sattr.inspect}"
+              m = @current.next( sattr )
+              #puts "Got #{m.inspect}"
+              if m 
+                # If the state has text children...
+                #puts "Looking for #{eattr.inspect}"
+                #puts "Expect #{m.expected}"
+                if m.matches?( eattr )
+                  #puts "Got end"
+                  @current = m
+                else
+                  #puts "Didn't get end"
+                  text[1] = v
+                  #puts "Looking for #{text.inspect}"
+                  m = m.next( text )
+                  #puts "Got #{m.inspect}"
+                  text[1] = nil
+                  return false unless m
+                  @current = m if m
+                end
+                m = @current.next( eattr )
+                if m
+                  @current = m
+                  true
+                else
+                  false
+                end
+              else
+                false
+              end
+            }
+            event[2].delete(k) if k
+          end while k
+        when :end_element
+          attrs = @attr_stack.pop
+          raise ValidationException.new( "Validation error.  Illegal "+
+            " attributes: #{attrs.inspect}") if attrs.length > 0
+        end
+      end
+    end
+
+    class Event
+      def initialize(event_type, event_arg=nil )
+        @event_type = event_type
+        @event_arg = event_arg
+      end
+
+      attr_reader :done?
+      attr_reader :event_type
+      attr_accessor :event_arg
+
+      def single?
+        return (@event_type != :start_element and @event_type != :start_attribute)
+      end
+
+      def matches?( event )
+        #puts "#@event_type =? #{event[0]} && #@event_arg =? #{event[1]} "
+        return false unless event[0] == @event_type
+        case event[0]
+        when nil
+          return true
+        when :start_element
+          return true if event[1] == @event_arg
+        when :end_element
+          return true
+        when :start_attribute
+          return true if event[1] == @event_arg
+        when :end_attribute
+          return true
+        when :end_document
+          return true
+        when :text
+          return (@event_arg.nil? or @event_arg == event[1])
+=begin
+        when :processing_instruction
+          false
+        when :xmldecl
+          false
+        when :start_doctype
+          false
+        when :end_doctype
+          false
+        when :externalentity
+          false
+        when :elementdecl
+          false
+        when :entity
+          false
+        when :attlistdecl
+          false
+        when :notationdecl
+          false
+        when :end_doctype
+          false
+=end
+        else
+          false
+        end
+      end
+
+      def ==( other )
+        return false unless other.kind_of? Event
+        @event_type == other.event_type and @event_arg == other.event_arg
+      end
+
+      def to_s
+        inspect
+      end
+
+      def inspect
+        "#{@event_type.inspect}( #@event_arg )"
+      end
+    end
+  end
+end