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#, slurp=true if arg.kind_of? String source = Source.new(arg) elsif arg.kind_of? IO source = IOSource.new(arg) end source 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 def initialize(arg) @orig = @buffer = arg self.encoding = check_encoding( @buffer ) @line = 0 end # Inherited from Encoding # Overridden to support optimized en/decoding def encoding=(enc) super @line_break = encode( '>' ) if enc != UTF_8 @buffer = decode(@buffer) @to_utf = true else @to_utf = false 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 # @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) @er_source = @source = arg @to_utf = false # FIXME # This is broken. If the user puts in enough carriage returns, this can fail # to calculate the correct encoding. super @source.read( 100 ) @line_break = encode( '>' ) 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 @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 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 # @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