diff options
Diffstat (limited to 'ruby_1_8_6/lib/rexml/parsers/pullparser.rb')
| -rw-r--r-- | ruby_1_8_6/lib/rexml/parsers/pullparser.rb | 196 |
1 files changed, 196 insertions, 0 deletions
diff --git a/ruby_1_8_6/lib/rexml/parsers/pullparser.rb b/ruby_1_8_6/lib/rexml/parsers/pullparser.rb new file mode 100644 index 0000000000..36dc7160c3 --- /dev/null +++ b/ruby_1_8_6/lib/rexml/parsers/pullparser.rb @@ -0,0 +1,196 @@ +require 'forwardable' + +require 'rexml/parseexception' +require 'rexml/parsers/baseparser' +require 'rexml/xmltokens' + +module REXML + module Parsers + # = Using the Pull Parser + # <em>This API is experimental, and subject to change.</em> + # parser = PullParser.new( "<a>text<b att='val'/>txet</a>" ) + # while parser.has_next? + # res = parser.next + # puts res[1]['att'] if res.start_tag? and res[0] == 'b' + # end + # See the PullEvent class for information on the content of the results. + # The data is identical to the arguments passed for the various events to + # the StreamListener API. + # + # Notice that: + # parser = PullParser.new( "<a>BAD DOCUMENT" ) + # while parser.has_next? + # res = parser.next + # raise res[1] if res.error? + # end + # + # Nat Price gave me some good ideas for the API. + class PullParser + include XMLTokens + extend Forwardable + + def_delegators( :@parser, :has_next? ) + def_delegators( :@parser, :entity ) + def_delegators( :@parser, :empty? ) + def_delegators( :@parser, :source ) + + def initialize stream + @entities = {} + @listeners = nil + @parser = BaseParser.new( stream ) + @my_stack = [] + end + + def add_listener( listener ) + @listeners = [] unless @listeners + @listeners << listener + end + + def each + while has_next? + yield self.pull + end + end + + def peek depth=0 + if @my_stack.length <= depth + (depth - @my_stack.length + 1).times { + e = PullEvent.new(@parser.pull) + @my_stack.push(e) + } + end + @my_stack[depth] + end + + def pull + return @my_stack.shift if @my_stack.length > 0 + + event = @parser.pull + case event[0] + when :entitydecl + @entities[ event[1] ] = + event[2] unless event[2] =~ /PUBLIC|SYSTEM/ + when :text + unnormalized = @parser.unnormalize( event[1], @entities ) + event << unnormalized + end + PullEvent.new( event ) + end + + def unshift token + @my_stack.unshift token + end + end + + # A parsing event. The contents of the event are accessed as an +Array?, + # and the type is given either by the ...? methods, or by accessing the + # +type+ accessor. The contents of this object vary from event to event, + # but are identical to the arguments passed to +StreamListener+s for each + # event. + class PullEvent + # The type of this event. Will be one of :tag_start, :tag_end, :text, + # :processing_instruction, :comment, :doctype, :attlistdecl, :entitydecl, + # :notationdecl, :entity, :cdata, :xmldecl, or :error. + def initialize(arg) + @contents = arg + end + + def []( start, endd=nil) + if start.kind_of? Range + @contents.slice( start.begin+1 .. start.end ) + elsif start.kind_of? Numeric + if endd.nil? + @contents.slice( start+1 ) + else + @contents.slice( start+1, endd ) + end + else + raise "Illegal argument #{start.inspect} (#{start.class})" + end + end + + def event_type + @contents[0] + end + + # Content: [ String tag_name, Hash attributes ] + def start_element? + @contents[0] == :start_element + end + + # Content: [ String tag_name ] + def end_element? + @contents[0] == :end_element + end + + # Content: [ String raw_text, String unnormalized_text ] + def text? + @contents[0] == :text + end + + # Content: [ String text ] + def instruction? + @contents[0] == :processing_instruction + end + + # Content: [ String text ] + def comment? + @contents[0] == :comment + end + + # Content: [ String name, String pub_sys, String long_name, String uri ] + def doctype? + @contents[0] == :start_doctype + end + + # Content: [ String text ] + def attlistdecl? + @contents[0] == :attlistdecl + end + + # Content: [ String text ] + def elementdecl? + @contents[0] == :elementdecl + end + + # Due to the wonders of DTDs, an entity declaration can be just about + # anything. There's no way to normalize it; you'll have to interpret the + # content yourself. However, the following is true: + # + # * If the entity declaration is an internal entity: + # [ String name, String value ] + # Content: [ String text ] + def entitydecl? + @contents[0] == :entitydecl + end + + # Content: [ String text ] + def notationdecl? + @contents[0] == :notationdecl + end + + # Content: [ String text ] + def entity? + @contents[0] == :entity + end + + # Content: [ String text ] + def cdata? + @contents[0] == :cdata + end + + # Content: [ String version, String encoding, String standalone ] + def xmldecl? + @contents[0] == :xmldecl + end + + def error? + @contents[0] == :error + end + + def inspect + @contents[0].to_s + ": " + @contents[1..-1].inspect + end + end + end +end |