diff -r 83c0eed6db19 -r 9e127bf6e84f chunker/lib/chunker.rb --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/chunker/lib/chunker.rb Sat Nov 08 18:59:05 2008 +0000 @@ -0,0 +1,125 @@ +# +# Chunker! +# +# Mahlon E. Smith +# + + +### Namespace for the datablock parser. +### +module Chunker + + require 'strscan' + require 'stringio' + + # SVN Revision + # + SVNRev = %q$Rev$ + + # SVN Id + # + SVNId = %q$Id$ + + # Package version + # + VERSION = '0.1' + + + ### Parser class for __END__ data blocks. + ### Find each __MARKER__ within the __END__, and put each into a + ### DATA_MARKER constant within the namespace that included us. + ### + class DataParser + + # The mark for a DATA block. + # + END_MARKER = /^__END__\r?\n/ + + # The mark for a 'sub' block. + # + CHUNK_MARKER = /^__([A-Z\_0-9]+)__\r?\n/ + + + ### Constructor: Given a +klass+ and an +io+ to the class file, + ### extract the data blocks and install constants. + ### + def initialize( klass, io ) + io.open if io.closed? + end_string = io.read.split( END_MARKER, 2 ).last + + @klass = klass + @scanner = StringScanner.new( end_string ) + io.close + + if @scanner.check_until( CHUNK_MARKER ) + # put each chunk into its own constant + self.extract_blocks + else + # no sub blocks, put the whole mess into DATA_END + @klass.const_set( :DATA_END, StringIO.new( end_string ) ) + end + end + + + ######### + protected + ######### + + ### Parse the current +io+ for data blocks, set contents to + ### IO constants in the including class. + ### + def extract_blocks + label = nil + + while @scanner.scan_until( CHUNK_MARKER ) and ! @scanner.eos? + data = '' + + # First pass, __END__ contents (until next marker, instead + # of entire data block.) + # + if label.nil? + label = 'END' + data = @scanner.pre_match + + @scanner.pos = self.next_position + else + label = @scanner[1] + + if data = @scanner.scan_until( CHUNK_MARKER ) + # Pull the next marker text out of the data, set up the next pass + # + data = data[ 0, data.length - @scanner[0].length ] + @scanner.pos = self.next_position + else + # No additional blocks + # + data = @scanner.rest + end + end + + # Add the IO constant to the class that included me. + # + @klass.const_set( "DATA_#{label}".to_sym, StringIO.new( data ) ) + end + end + + + ### Return the next scanner position for searching. + ### + def next_position + return @scanner.pos - @scanner[0].length + end + end + + + ### Included hook: Find the file path for how we arrived here, and open + ### it as an IO object. __FILE__ won't work, so we find it via caller(). + ### Start parsing this file for data blocks. + ### + def self.included( klass ) + # klass.instance_eval{ __FILE__ } awww, nope. + io = File.open( caller(1).last.sub(/:.*?$/, ''), 'r' ) + DataParser.new( klass, io ) + end +end +