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EDIT :: tar_writer.rb

# -*- coding: utf-8 -*- #-- # Copyright (C) 2004 Mauricio Julio Fernández Pradier # See LICENSE.txt for additional licensing information. #++ ## # Allows writing of tar files class Gem::Package::TarWriter class FileOverflow < StandardError; end ## # IO wrapper that allows writing a limited amount of data class BoundedStream ## # Maximum number of bytes that can be written attr_reader :limit ## # Number of bytes written attr_reader :written ## # Wraps +io+ and allows up to +limit+ bytes to be written def initialize(io, limit) @io = io @limit = limit @written = 0 end ## # Writes +data+ onto the IO, raising a FileOverflow exception if the # number of bytes will be more than #limit def write(data) if data.size + @written > @limit raise FileOverflow, "You tried to feed more data than fits in the file." end @io.write data @written += data.size data.size end end ## # IO wrapper that provides only #write class RestrictedStream ## # Creates a new RestrictedStream wrapping +io+ def initialize(io) @io = io end ## # Writes +data+ onto the IO def write(data) @io.write data end end ## # Creates a new TarWriter, yielding it if a block is given def self.new(io) writer = super return writer unless block_given? begin yield writer ensure writer.close end nil end ## # Creates a new TarWriter that will write to +io+ def initialize(io) @io = io @closed = false end ## # Adds file +name+ with permissions +mode+, and yields an IO for writing the # file to def add_file(name, mode) # :yields: io check_closed raise Gem::Package::NonSeekableIO unless @io.respond_to? :pos= name, prefix = split_name name init_pos = @io.pos @io.write "\0" * 512 # placeholder for the header yield RestrictedStream.new(@io) if block_given? size = @io.pos - init_pos - 512 remainder = (512 - (size % 512)) % 512 @io.write "\0" * remainder final_pos = @io.pos @io.pos = init_pos header = Gem::Package::TarHeader.new :name => name, :mode => mode, :size => size, :prefix => prefix @io.write header @io.pos = final_pos self end ## # Add file +name+ with permissions +mode+ +size+ bytes long. Yields an IO # to write the file to. def add_file_simple(name, mode, size) # :yields: io check_closed name, prefix = split_name name header = Gem::Package::TarHeader.new(:name => name, :mode => mode, :size => size, :prefix => prefix).to_s @io.write header os = BoundedStream.new @io, size yield os if block_given? min_padding = size - os.written @io.write("\0" * min_padding) remainder = (512 - (size % 512)) % 512 @io.write("\0" * remainder) self end ## # Raises IOError if the TarWriter is closed def check_closed raise IOError, "closed #{self.class}" if closed? end ## # Closes the TarWriter def close check_closed @io.write "\0" * 1024 flush @closed = true end ## # Is the TarWriter closed? def closed? @closed end ## # Flushes the TarWriter's IO def flush check_closed @io.flush if @io.respond_to? :flush end ## # Creates a new directory in the tar file +name+ with +mode+ def mkdir(name, mode) check_closed name, prefix = split_name(name) header = Gem::Package::TarHeader.new :name => name, :mode => mode, :typeflag => "5", :size => 0, :prefix => prefix @io.write header self end ## # Splits +name+ into a name and prefix that can fit in the TarHeader def split_name(name) # :nodoc: raise Gem::Package::TooLongFileName if name.size > 256 if name.size <= 100 then prefix = "" else parts = name.split(/\//) newname = parts.pop nxt = "" loop do nxt = parts.pop break if newname.size + 1 + nxt.size > 100 newname = nxt + "/" + newname end prefix = (parts + [nxt]).join "/" name = newname if name.size > 100 or prefix.size > 155 then raise Gem::Package::TooLongFileName end end return name, prefix end end

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