Current File : //proc/thread-self/root/opt/alt/ruby19/lib64/ruby/1.9.1/rubygems/package/tar_reader.rb
# -*- coding: utf-8 -*-
#--
# Copyright (C) 2004 Mauricio Julio Fernández Pradier
# See LICENSE.txt for additional licensing information.
#++
##
# TarReader reads tar files and allows iteration over their items
class Gem::Package::TarReader
include Gem::Package
##
# Raised if the tar IO is not seekable
class UnexpectedEOF < StandardError; end
##
# Creates a new TarReader on +io+ and yields it to the block, if given.
def self.new(io)
reader = super
return reader unless block_given?
begin
yield reader
ensure
reader.close
end
nil
end
##
# Creates a new tar file reader on +io+ which needs to respond to #pos,
# #eof?, #read, #getc and #pos=
def initialize(io)
@io = io
@init_pos = io.pos
end
##
# Close the tar file
def close
end
##
# Iterates over files in the tarball yielding each entry
def each
loop do
return if @io.eof?
header = Gem::Package::TarHeader.from @io
return if header.empty?
entry = Gem::Package::TarReader::Entry.new header, @io
size = entry.header.size
yield entry
skip = (512 - (size % 512)) % 512
pending = size - entry.bytes_read
begin
# avoid reading...
@io.seek pending, IO::SEEK_CUR
pending = 0
rescue Errno::EINVAL, NameError
while pending > 0 do
bytes_read = @io.read([pending, 4096].min).size
raise UnexpectedEOF if @io.eof?
pending -= bytes_read
end
end
@io.read skip # discard trailing zeros
# make sure nobody can use #read, #getc or #rewind anymore
entry.close
end
end
alias each_entry each
##
# NOTE: Do not call #rewind during #each
def rewind
if @init_pos == 0 then
raise Gem::Package::NonSeekableIO unless @io.respond_to? :rewind
@io.rewind
else
raise Gem::Package::NonSeekableIO unless @io.respond_to? :pos=
@io.pos = @init_pos
end
end
end
require 'rubygems/package/tar_reader/entry'
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