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Diffstat (limited to 'ruby/lib/rexml/source.rb')
| -rw-r--r-- | ruby/lib/rexml/source.rb | 258 |
1 files changed, 258 insertions, 0 deletions
diff --git a/ruby/lib/rexml/source.rb b/ruby/lib/rexml/source.rb new file mode 100644 index 0000000..d433513 --- /dev/null +++ b/ruby/lib/rexml/source.rb @@ -0,0 +1,258 @@ +require 'rexml/encoding' + +module REXML + # Generates Source-s. USE THIS CLASS. + class SourceFactory + # Generates a Source object + # @param arg Either a String, or an IO + # @return a Source, or nil if a bad argument was given + def SourceFactory::create_from(arg) + if arg.respond_to? :read and + arg.respond_to? :readline and + arg.respond_to? :nil? and + arg.respond_to? :eof? + IOSource.new(arg) + elsif arg.respond_to? :to_str + require 'stringio' + IOSource.new(StringIO.new(arg)) + elsif arg.kind_of? Source + arg + else + raise "#{arg.class} is not a valid input stream. It must walk \n"+ + "like either a String, an IO, or a Source." + end + end + end + + # A Source can be searched for patterns, and wraps buffers and other + # objects and provides consumption of text + class Source + include Encoding + # The current buffer (what we're going to read next) + attr_reader :buffer + # The line number of the last consumed text + attr_reader :line + attr_reader :encoding + + # Constructor + # @param arg must be a String, and should be a valid XML document + # @param encoding if non-null, sets the encoding of the source to this + # value, overriding all encoding detection + def initialize(arg, encoding=nil) + @orig = @buffer = arg + if encoding + self.encoding = encoding + else + self.encoding = check_encoding( @buffer ) + end + @line = 0 + end + + + # Inherited from Encoding + # Overridden to support optimized en/decoding + def encoding=(enc) + return unless super + @line_break = encode( '>' ) + if enc != UTF_8 + @buffer = decode(@buffer) + @to_utf = true + else + @to_utf = false + if @buffer.respond_to? :force_encoding + @buffer.force_encoding Encoding::UTF_8 + end + end + end + + # Scans the source for a given pattern. Note, that this is not your + # usual scan() method. For one thing, the pattern argument has some + # requirements; for another, the source can be consumed. You can easily + # confuse this method. Originally, the patterns were easier + # to construct and this method more robust, because this method + # generated search regexes on the fly; however, this was + # computationally expensive and slowed down the entire REXML package + # considerably, since this is by far the most commonly called method. + # @param pattern must be a Regexp, and must be in the form of + # /^\s*(#{your pattern, with no groups})(.*)/. The first group + # will be returned; the second group is used if the consume flag is + # set. + # @param consume if true, the pattern returned will be consumed, leaving + # everything after it in the Source. + # @return the pattern, if found, or nil if the Source is empty or the + # pattern is not found. + def scan(pattern, cons=false) + return nil if @buffer.nil? + rv = @buffer.scan(pattern) + @buffer = $' if cons and rv.size>0 + rv + end + + def read + end + + def consume( pattern ) + @buffer = $' if pattern.match( @buffer ) + end + + def match_to( char, pattern ) + return pattern.match(@buffer) + end + + def match_to_consume( char, pattern ) + md = pattern.match(@buffer) + @buffer = $' + return md + end + + def match(pattern, cons=false) + md = pattern.match(@buffer) + @buffer = $' if cons and md + return md + end + + # @return true if the Source is exhausted + def empty? + @buffer == "" + end + + def position + @orig.index( @buffer ) + end + + # @return the current line in the source + def current_line + lines = @orig.split + res = lines.grep @buffer[0..30] + res = res[-1] if res.kind_of? Array + lines.index( res ) if res + end + end + + # A Source that wraps an IO. See the Source class for method + # documentation + class IOSource < Source + #attr_reader :block_size + + # block_size has been deprecated + def initialize(arg, block_size=500, encoding=nil) + @er_source = @source = arg + @to_utf = false + + # Determining the encoding is a deceptively difficult issue to resolve. + # First, we check the first two bytes for UTF-16. Then we + # assume that the encoding is at least ASCII enough for the '>', and + # we read until we get one of those. This gives us the XML declaration, + # if there is one. If there isn't one, the file MUST be UTF-8, as per + # the XML spec. If there is one, we can determine the encoding from + # it. + @buffer = "" + str = @source.read( 2 ) || '' + if encoding + self.encoding = encoding + elsif str[0,2] == "\xfe\xff" + @line_break = "\000>" + elsif str[0,2] == "\xff\xfe" + @line_break = ">\000" + elsif str[0,2] == "\xef\xbb" + str += @source.read(1) + str = '' if (str[2,1] == "\xBF") + @line_break = ">" + else + @line_break = ">" + end + super( @source.eof? ? str : str+@source.readline( @line_break ) ) + end + + def scan(pattern, cons=false) + rv = super + # You'll notice that this next section is very similar to the same + # section in match(), but just a liiittle different. This is + # because it is a touch faster to do it this way with scan() + # than the way match() does it; enough faster to warrent duplicating + # some code + if rv.size == 0 + until @buffer =~ pattern or @source.nil? + begin + # READLINE OPT + #str = @source.read(@block_size) + str = @source.readline(@line_break) + str = decode(str) if @to_utf and str + @buffer << str + rescue Iconv::IllegalSequence + raise + rescue + @source = nil + end + end + rv = super + end + rv.taint + rv + end + + def read + begin + str = @source.readline(@line_break) + str = decode(str) if @to_utf and str + @buffer << str + if not @to_utf and @buffer.respond_to? :force_encoding + @buffer.force_encoding Encoding::UTF_8 + end + rescue Exception, NameError + @source = nil + end + end + + def consume( pattern ) + match( pattern, true ) + end + + def match( pattern, cons=false ) + rv = pattern.match(@buffer) + @buffer = $' if cons and rv + while !rv and @source + begin + str = @source.readline(@line_break) + str = decode(str) if @to_utf and str + @buffer << str + rv = pattern.match(@buffer) + @buffer = $' if cons and rv + rescue + @source = nil + end + end + rv.taint + rv + end + + def empty? + super and ( @source.nil? || @source.eof? ) + end + + def position + @er_source.pos rescue 0 + end + + # @return the current line in the source + def current_line + begin + pos = @er_source.pos # The byte position in the source + lineno = @er_source.lineno # The XML < position in the source + @er_source.rewind + line = 0 # The \r\n position in the source + begin + while @er_source.pos < pos + @er_source.readline + line += 1 + end + rescue + end + rescue IOError + pos = -1 + line = -1 + end + [pos, lineno, line] + end + end +end |