summaryrefslogtreecommitdiff
path: root/lib/rexml/parsers/baseparser.rb
blob: 614bdc3948a1c792a5a6c4b80b3fe1bbdd781866 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
require 'rexml/parseexception'
require 'rexml/source'

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 BaseParser
			NCNAME_STR= '[\w:][-\w\d.]*'
			NAME_STR= "(?:#{NCNAME_STR}:)?#{NCNAME_STR}"

			NAMECHAR = '[-\w\d\.:]'
			NAME = "([\\w:]#{NAMECHAR}*)"
			NMTOKEN = "(?:#{NAMECHAR})+"
			NMTOKENS = "#{NMTOKEN}(\\s+#{NMTOKEN})*"
			REFERENCE = "(?:&#{NAME};|&#\\d+;|&#x[0-9a-fA-F]+;)"

			DOCTYPE_START = /\A\s*<!DOCTYPE\s/um
			DOCTYPE_PATTERN = /\s*<!DOCTYPE\s+(.*?)(\[|>)/um
			ATTRIBUTE_PATTERN = /\s*(#{NAME_STR})\s*=\s*(["'])(.*?)\2/um
			COMMENT_START = /\A<!--/u
			COMMENT_PATTERN = /<!--(.*?)-->/um
			CDATA_START = /\A<!\[CDATA\[/u
			CDATA_PATTERN = /<!\[CDATA\[(.*?)\]\]>/um
			XMLDECL_START = /\A<\?xml\s/u;
			XMLDECL_PATTERN = /<\?xml\s+(.*?)\?>*/um
			INSTRUCTION_START = /\A<\?/u
			INSTRUCTION_PATTERN = /<\?(.*?)(\s+.*?)?\?>/um
			TAG_MATCH = /^<((?>#{NAME_STR}))\s*((?>\s+#{NAME_STR}\s*=\s*(["']).*?\3)*)\s*(\/)?>/um
			CLOSE_MATCH = /^\s*<\/(#{NAME_STR})\s*>/um

			VERSION = /\bversion\s*=\s*["'](.*?)['"]/um
			ENCODING = /\bencoding=["'](.*?)['"]/um
			STANDALONE = /\bstandalone=["'](.*?)['"]/um

			ENTITY_START = /^\s*<!ENTITY/
			IDENTITY = /^([!\*\w-]+)(\s+#{NCNAME_STR})?(\s+["'].*?['"])?(\s+['"].*?["'])?/u
			ELEMENTDECL_START = /^\s*<!ELEMENT/um
			ELEMENTDECL_PATTERN = /^\s*(<!ELEMENT.*?)>/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}"
			ATTLISTDECL_START = /^\s*<!ATTLIST/um
			ATTLISTDECL_PATTERN = /^\s*<!ATTLIST\s+#{NAME}(?:#{ATTDEF})*\s*>/um
			NOTATIONDECL_START = /^\s*<!NOTATION/um
			PUBLIC = /^\s*<!NOTATION\s+(\w[-\w]*)\s+(PUBLIC)\s+((["']).*?\4)\s*>/um
			SYSTEM = /^\s*<!NOTATION\s+(\w[-\w]*)\s+(SYSTEM)\s+((["']).*?\4)\s*>/um

			TEXT_PATTERN = /\A([^<]*)/um

			# Entity constants
			PUBIDCHAR = "\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;", "'"] 
			}

			def initialize( source )
				self.stream = source
			end

			def stream=( source )
				if source.kind_of? String
					@source = Source.new(source)
				elsif source.kind_of? IO
					@source = IOSource.new(source)
				elsif source.kind_of? Source
					@source = source
				else
					raise "#{source.type} is not a valid input stream.  It must be \n"+
					"either a String, IO, or Source."
				end
				@closed = nil
				@document_status = nil
				@tags = []
				@stack = []
				@entities = []
			end

			# Returns true if there are no more events
			def empty?
				!has_next?
			end

			# Returns true if there are more events.  Synonymous with !empty?
			def has_next?
				@source.read if @source.buffer.size==0 and !@source.empty?
				(!@source.empty? and @source.buffer.strip.size>0) or @stack.size>0 or @closed
			end

			# Push an event back on the head of the stream.  This method
			# has (theoretically) infinite depth.
			def unshift token
				@stack.unshift(token)
			end

			# 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.  
			def peek depth=0
				raise '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

			# Returns the next event.  This is a +PullEvent+ object.
			def pull
				return [ :end_document ] if empty?
				if @closed
					x, @closed = @closed, nil
					return [ :end_element, x ]
				end
				return @stack.shift if @stack.size > 0
				@source.read if @source.buffer.size==0
				if @document_status == nil
					@source.match( /^\s*/um, true )
					word = @source.match( /^\s*(<.*?)>/um )
					word = word[1] unless word.nil?
					case word
					when COMMENT_START
						return [ :comment, @source.match( COMMENT_PATTERN, true )[1] ]
					when XMLDECL_START
						results = @source.match( XMLDECL_PATTERN, true )[1]
						version = VERSION.match( results )
						version = version[1] unless version.nil?
						encoding = ENCODING.match(results)
						encoding = encoding[1] unless encoding.nil?
						@source.encoding = encoding
						standalone = STANDALONE.match(results)
						standalone = standalone[1] unless standalone.nil?
						return [ :xmldecl, version, encoding, standalone]
					when INSTRUCTION_START
						return [ :processing_instruction, *@source.match(INSTRUCTION_PATTERN, true)[1,2] ]
					when DOCTYPE_START
						md = @source.match( DOCTYPE_PATTERN, true )
						identity = md[1]
						close = md[2]
						identity =~ IDENTITY
						name = $1
						raise "DOCTYPE is missing a name" if name.nil?
						pub_sys = $2.nil? ? nil : $2.strip
						long_name = $3.nil? ? nil : $3.strip
						uri = $4.nil? ? nil : $4.strip
						args = [ :start_doctype, name, pub_sys, long_name, uri ]
						if close == ">"
							@document_status = :after_doctype
							@source.read if @source.buffer.size==0
							md = @source.match(/^\s*/um, true)
							@stack << [ :end_doctype ]
						else
							@document_status = :in_doctype
						end
						return args
					else
						@document_status = :after_doctype
						@source.read if @source.buffer.size==0
						md = @source.match(/\s*/um, true)
					end
				end
				if @document_status == :in_doctype
					md = @source.match(/\s*(.*?>)/um)
					case md[1]
					when ELEMENTDECL_START
						return [ :elementdecl, @source.match( ELEMENTDECL_PATTERN, true )[1] ]
					when ENTITY_START
						match = @source.match( ENTITYDECL, true ).to_a.compact
						match[0] = :entitydecl
						ref = false
						if match[1] == '%'
							ref = true
							match.delete_at 1
						end
						# Now we have to sort out what kind of entity reference this is
						if match[2] == 'SYSTEM'
							# External reference
							match[3] = match[3][1..-2] # PUBID
							match.delete_at(4) if match.size > 4 # Chop out NDATA decl
							# match is [ :entity, name, SYSTEM, pubid(, ndata)? ]
						elsif match[2] == 'PUBLIC'
							# External reference
							match[3] = match[3][1..-2] # PUBID
							match[4] = match[4][1..-2] # HREF
							# match is [ :entity, name, PUBLIC, pubid, href ]
						else
							match[2] = match[2][1..-2]
							match.pop if match.size == 4
							# match is [ :entity, name, value ]
						end
						match << '%' if ref
						return match
					when ATTLISTDECL_START
						md = @source.match( ATTLISTDECL_PATTERN, true )
						raise REXML::ParseException.new( "Bad ATTLIST declaration!", @source ) if md.nil?
						element = md[1]
						contents = md[0]

						pairs = {}
						values = md[0].scan( ATTDEF )
						values.each do |attdef|
							unless attdef[3] == "#IMPLIED"
								attdef.compact!
								val = attdef[3]
								val = attdef[4] if val == "#FIXED "
								pairs[attdef[0]] = val
							end
						end
						return [ :attlistdecl, element, pairs, contents ]
					when NOTATIONDECL_START
						md = nil
						if @source.match( PUBLIC )
							md = @source.match( PUBLIC, true )
						elsif @source.match( SYSTEM )
							md = @source.match( SYSTEM, true )
						else
							raise REXML::ParseException.new( "error parsing notation: no matching pattern", @source )
						end
						return [ :notationdecl, md[1], md[2], md[3] ]
					when /^\s*\]\s*>/um
						@document_status = :after_doctype
						@source.match( /^\s*\]\s*>/um, true )
						return [ :end_doctype ]
					end
				end
				begin 
					if @source.buffer[0] == ?<
						if @source.buffer[1] == ?/
							last_tag = @tags.pop
							md = @source.match( CLOSE_MATCH, true )
							raise REXML::ParseException.new( "Missing end tag for '#{last_tag}' "+
								"(got \"#{md[1]}\")", @source) unless last_tag == md[1]
							return [ :end_element, last_tag ]
						elsif @source.buffer[1] == ?!
							md = @source.match(/\A(\s*[^>]*>)/um)
							#puts "SOURCE BUFFER = #{source.buffer}, #{source.buffer.size}"
							raise REXML::ParseException.new("Malformed node", @source) unless md
							case md[1]
							when CDATA_START
								return [ :cdata, @source.match( CDATA_PATTERN, true )[1] ]
							when COMMENT_START
								return [ :comment, @source.match( COMMENT_PATTERN, true )[1] ]
							else
								raise REXML::ParseException.new( "Declarations can only occur "+
								"in the doctype declaration.", @source)
							end
						elsif @source.buffer[1] == ??
							md = @source.match( INSTRUCTION_PATTERN, true )
							return [ :processing_instruction, md[1], md[2] ]
						else
							# Get the next tag
							md = @source.match(TAG_MATCH, true)
							raise REXML::ParseException.new("malformed XML: missing tag start", @source) unless md
							attrs = []
							if md[2].size > 0
								attrs = md[2].scan( ATTRIBUTE_PATTERN )
								raise REXML::ParseException.new( "error parsing attributes: [#{attrs.join ', '}], excess = \"#$'\"", @source) if $' and $'.strip.size > 0
							end
				
							if md[4]
								@closed = md[1]
							else
								@tags.push( md[1] )
							end
							attributes = {}
							attrs.each { |a,b,c| attributes[a] = c }
							return [ :start_element, md[1], attributes ]
						end
					else
						md = @source.match(TEXT_PATTERN, true)
						raise "no text to add" if md[0].length == 0
						# unnormalized = Text::unnormalize( md[1], self )
						# return PullEvent.new( :text, md[1], unnormalized )
						return [ :text, md[1] ]
					end
        rescue REXML::ParseException
          raise $!
				rescue Exception, NameError => error
					raise REXML::ParseException.new( "Exception parsing",
						@source, self, error )
				end
				return [ :dummy ]
			end

			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

			# Escapes all possible entities
			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[2], value[1] )
				end
				copy
			end

			# Unescapes all possible entities
			def unnormalize( string, entities=nil, filter=nil )
				rv = string.clone
				rv.gsub!( /\r\n?/, "\n" )
				matches = rv.scan( REFERENCE)
				return rv if matches.size == 0
				rv.gsub!( /&#0*((?:\d+)|(?:x[a-fA-F0-9]+));/ ) {|m|
					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 )
							end
						end
					end
					matches.each do |entity_reference|
						unless filter and filter.include?(entity_reference)
							er = DEFAULT_ENTITIES[entity_reference]
							rv.gsub!( er[0], er[2] ) if er
						end
					end
					rv.gsub!( /&amp;/, '&' )
				end
				rv
			end
		end
	end
end