Class: REXML::Parsers::BaseParser

Inherits:
Object
  • Object
show all
Defined in:
lib/rexml/parsers/baseparser.rb

Overview

Using the Pull Parser

This API is experimental, and subject to change.

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.

Constant Summary collapse

LETTER = 
'[:alpha:]'
DIGIT = 
'[:digit:]'
COMBININGCHAR =

TODO

''
EXTENDER =

TODO

''
NCNAME_STR = 
"[#{LETTER}_][-[:alnum:]._#{COMBININGCHAR}#{EXTENDER}]*"
QNAME_STR = 
"(?:(#{NCNAME_STR}):)?(#{NCNAME_STR})"
QNAME = 
/(#{QNAME_STR})/
UNAME_STR =

Just for backward compatibility. For example, kramdown uses this. It’s not used in REXML.

"(?:#{NCNAME_STR}:)?#{NCNAME_STR}"
NAMECHAR = 
'[\-\w\.:]'
NAME = 
"([\\w:]#{NAMECHAR}*)"
NMTOKEN = 
"(?:#{NAMECHAR})+"
NMTOKENS = 
"#{NMTOKEN}(\\s+#{NMTOKEN})*"
REFERENCE = 
"&(?:#{NAME};|#\\d+;|#x[0-9a-fA-F]+;)"
REFERENCE_RE = 
/#{REFERENCE}/
DOCTYPE_START = 
/\A\s*<!DOCTYPE\s/um
DOCTYPE_END = 
/\A\s*\]\s*>/um
DOCTYPE_PATTERN = 
/\s*<!DOCTYPE\s+(.*?)(\[|>)/um
ATTRIBUTE_PATTERN = 
/\s*(#{QNAME_STR})\s*=\s*(["'])(.*?)\4/um
COMMENT_START = 
/\A<!--/u
COMMENT_PATTERN = 
/<!--(.*?)-->/um
CDATA_START = 
/\A<!\[CDATA\[/u
CDATA_END = 
/\A\s*\]\s*>/um
CDATA_PATTERN = 
/<!\[CDATA\[(.*?)\]\]>/um
XMLDECL_START = 
/\A<\?xml\s/u
XMLDECL_PATTERN = 
/<\?xml\s+(.*?)\?>/um
INSTRUCTION_START = 
/\A<\?/u
INSTRUCTION_PATTERN = 
/<\?#{NAME}(\s+.*?)?\?>/um
TAG_MATCH = 
/^<((?>#{QNAME_STR}))/um
CLOSE_MATCH = 
/^\s*<\/(#{QNAME_STR})\s*>/um
VERSION = 
/\bversion\s*=\s*["'](.*?)['"]/um
ENCODING = 
/\bencoding\s*=\s*["'](.*?)['"]/um
STANDALONE = 
/\bstandalone\s*=\s*["'](.*?)['"]/um
ENTITY_START = 
/\A\s*<!ENTITY/
IDENTITY = 
/^([!\*\w\-]+)(\s+#{NCNAME_STR})?(\s+["'](.*?)['"])?(\s+['"](.*?)["'])?/u
ELEMENTDECL_START = 
/\A\s*<!ELEMENT/um
ELEMENTDECL_PATTERN = 
/\A\s*(<!ELEMENT.*?)>/um
SYSTEMENTITY = 
/\A\s*(%.*?;)\s*$/um
ENUMERATION = 
"\\(\\s*#{NMTOKEN}(?:\\s*\\|\\s*#{NMTOKEN})*\\s*\\)"
NOTATIONTYPE = 
"NOTATION\\s+\\(\\s*#{NAME}(?:\\s*\\|\\s*#{NAME})*\\s*\\)"
ENUMERATEDTYPE = 
"(?:(?:#{NOTATIONTYPE})|(?:#{ENUMERATION}))"
ATTTYPE = 
"(CDATA|ID|IDREF|IDREFS|ENTITY|ENTITIES|NMTOKEN|NMTOKENS|#{ENUMERATEDTYPE})"
ATTVALUE = 
"(?:\"((?:[^<&\"]|#{REFERENCE})*)\")|(?:'((?:[^<&']|#{REFERENCE})*)')"
DEFAULTDECL = 
"(#REQUIRED|#IMPLIED|(?:(#FIXED\\s+)?#{ATTVALUE}))"
ATTDEF = 
"\\s+#{NAME}\\s+#{ATTTYPE}\\s+#{DEFAULTDECL}"
ATTDEF_RE = 
/#{ATTDEF}/
ATTLISTDECL_START = 
/\A\s*<!ATTLIST/um
ATTLISTDECL_PATTERN = 
/\A\s*<!ATTLIST\s+#{NAME}(?:#{ATTDEF})*\s*>/um
NOTATIONDECL_START = 
/\A\s*<!NOTATION/um
PUBLIC = 
/\A\s*<!NOTATION\s+(\w[\-\w]*)\s+(PUBLIC)\s+(["'])(.*?)\3(?:\s+(["'])(.*?)\5)?\s*>/um
SYSTEM = 
/\A\s*<!NOTATION\s+(\w[\-\w]*)\s+(SYSTEM)\s+(["'])(.*?)\3\s*>/um
TEXT_PATTERN = 
/\A([^<]*)/um
PUBIDCHAR =

Entity constants

"\x20\x0D\x0Aa-zA-Z0-9\\-()+,./:=?;!*@$_%#"
SYSTEMLITERAL = 
%Q{((?:"[^"]*")|(?:'[^']*'))}
PUBIDLITERAL = 
%Q{("[#{PUBIDCHAR}']*"|'[#{PUBIDCHAR}]*')}
EXTERNALID = 
"(?:(?:(SYSTEM)\\s+#{SYSTEMLITERAL})|(?:(PUBLIC)\\s+#{PUBIDLITERAL}\\s+#{SYSTEMLITERAL}))"
NDATADECL = 
"\\s+NDATA\\s+#{NAME}"
PEREFERENCE = 
"%#{NAME};"
ENTITYVALUE = 
%Q{((?:"(?:[^%&"]|#{PEREFERENCE}|#{REFERENCE})*")|(?:'([^%&']|#{PEREFERENCE}|#{REFERENCE})*'))}
PEDEF = 
"(?:#{ENTITYVALUE}|#{EXTERNALID})"
ENTITYDEF = 
"(?:#{ENTITYVALUE}|(?:#{EXTERNALID}(#{NDATADECL})?))"
PEDECL = 
"<!ENTITY\\s+(%)\\s+#{NAME}\\s+#{PEDEF}\\s*>"
GEDECL = 
"<!ENTITY\\s+#{NAME}\\s+#{ENTITYDEF}\\s*>"
ENTITYDECL = 
/\s*(?:#{GEDECL})|(?:#{PEDECL})/um
EREFERENCE = 
/&(?!#{NAME};)/
DEFAULT_ENTITIES = 
{
  'gt' => [/&gt;/, '&gt;', '>', />/],
  'lt' => [/&lt;/, '&lt;', '<', /</],
  'quot' => [/&quot;/, '&quot;', '"', /"/],
  "apos" => [/&apos;/, "&apos;", "'", /'/]
}

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(source) ⇒ BaseParser

Returns a new instance of BaseParser.



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# File 'lib/rexml/parsers/baseparser.rb', line 115

def initialize( source )
  self.stream = source
  @listeners = []
end

Instance Attribute Details

#source ⇒ Object (readonly)

Returns the value of attribute source



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# File 'lib/rexml/parsers/baseparser.rb', line 124

def source
  @source
end

Instance Method Details

#add_listener(listener) ⇒ Object 



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# File 'lib/rexml/parsers/baseparser.rb', line 120

def add_listener( listener )
  @listeners << listener
end

#empty? ⇒ Boolean

Returns true if there are no more events

Returns:

  • (Boolean) 


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# File 'lib/rexml/parsers/baseparser.rb', line 146

def empty?
  return (@source.empty? and @stack.empty?)
end

#entity(reference, entities) ⇒ Object 



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# File 'lib/rexml/parsers/baseparser.rb', line 417

def entity( reference, entities )
  value = nil
  value = entities[ reference ] if entities
  if not value
    value = DEFAULT_ENTITIES[ reference ]
    value = value[2] if value
  end
  unnormalize( value, entities ) if value
end

#has_next? ⇒ Boolean

Returns true if there are more events. Synonymous with !empty?

Returns:

  • (Boolean) 


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# File 'lib/rexml/parsers/baseparser.rb', line 151

def has_next?
  return !(@source.empty? and @stack.empty?)
end

#normalize(input, entities = nil, entity_filter = nil) ⇒ Object

Escapes all possible entities



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# File 'lib/rexml/parsers/baseparser.rb', line 428

def normalize( input, entities=nil, entity_filter=nil )
  copy = input.clone
  # Doing it like this rather than in a loop improves the speed
  copy.gsub!( EREFERENCE, '&amp;' )
  entities.each do |key, value|
    copy.gsub!( value, "&#{key};" ) unless entity_filter and
                                entity_filter.include?(entity)
  end if entities
  copy.gsub!( EREFERENCE, '&amp;' )
  DEFAULT_ENTITIES.each do |key, value|
    copy.gsub!( value[3], value[1] )
  end
  copy
end

#peek(depth = 0) ⇒ Object

Peek at the depth event in the stack. The first element on the stack is at depth 0. If depth is -1, will parse to the end of the input stream and return the last event, which is always :end_document. Be aware that this causes the stream to be parsed up to the depth event, so you can effectively pre-parse the entire document (pull the entire thing into memory) using this method.



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# File 'lib/rexml/parsers/baseparser.rb', line 167

def peek depth=0
  raise %Q[Illegal argument "#{depth}"] if depth < -1
  temp = []
  if depth == -1
    temp.push(pull()) until empty?
  else
    while @stack.size+temp.size < depth+1
      temp.push(pull())
    end
  end
  @stack += temp if temp.size > 0
  @stack[depth]
end

#position ⇒ Object 



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# File 'lib/rexml/parsers/baseparser.rb', line 136

def position
  if @source.respond_to? :position
    @source.position
  else
    # FIXME
    0
  end
end

#pull ⇒ Object

Returns the next event. This is a PullEvent object.



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# File 'lib/rexml/parsers/baseparser.rb', line 182

def pull
  pull_event.tap do |event|
    @listeners.each do |listener|
      listener.receive event
    end
  end
end

#stream=(source) ⇒ Object 



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# File 'lib/rexml/parsers/baseparser.rb', line 126

def stream=( source )
  @source = SourceFactory.create_from( source )
  @closed = nil
  @document_status = nil
  @tags = []
  @stack = []
  @entities = []
  @nsstack = []
end

#unnormalize(string, entities = nil, filter = nil) ⇒ Object

Unescapes all possible entities



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# File 'lib/rexml/parsers/baseparser.rb', line 444

def unnormalize( string, entities=nil, filter=nil )
  rv = string.clone
  rv.gsub!( /\r\n?/, "\n" )
  matches = rv.scan( REFERENCE_RE )
  return rv if matches.size == 0
  rv.gsub!( /&#0*((?:\d+)|(?:x[a-fA-F0-9]+));/ ) {
    m=$1
    m = "0#{m}" if m[0] == ?x
    [Integer(m)].pack('U*')
  }
  matches.collect!{|x|x[0]}.compact!
  if matches.size > 0
    matches.each do |entity_reference|
      unless filter and filter.include?(entity_reference)
        entity_value = entity( entity_reference, entities )
        if entity_value
          re = /&#{entity_reference};/
          rv.gsub!( re, entity_value )
        else
          er = DEFAULT_ENTITIES[entity_reference]
          rv.gsub!( er[0], er[2] ) if er
        end
      end
    end
    rv.gsub!( /&amp;/, '&' )
  end
  rv
end

#unshift(token) ⇒ Object

Push an event back on the head of the stream. This method has (theoretically) infinite depth.



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# File 'lib/rexml/parsers/baseparser.rb', line 157

def unshift token
  @stack.unshift(token)
end