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Editing File: /usr/share/rubygems/rubygems/package/old.rb

#--
# Copyright 2006 by Chad Fowler, Rich Kilmer, Jim Weirich and others.
# All rights reserved.
# See LICENSE.txt for permissions.
#++

##
# The format class knows the guts of the ancient .gem file format and provides
# the capability to read such ancient gems.
#
# Please pretend this doesn't exist.

class Gem::Package::Old < Gem::Package

undef_method :spec=

##
  # Creates a new old-format package reader for +gem+.  Old-format packages
  # cannot be written.

def initialize gem
    require 'fileutils'
    require 'zlib'
    Gem.load_yaml

@contents        = nil
    @gem             = gem
    @security_policy = nil
    @spec            = nil
  end

##
  # A list of file names contained in this gem

def contents
    verify

return @contents if @contents

open @gem, 'rb' do |io|
      read_until_dashes io # spec
      header = file_list io

@contents = header.map { |file| file['path'] }
    end
  end

##
  # Extracts the files in this package into +destination_dir+

def extract_files destination_dir
    verify

errstr = "Error reading files from gem"

open @gem, 'rb' do |io|
      read_until_dashes io # spec
      header = file_list io
      raise Gem::Exception, errstr unless header

header.each do |entry|
        full_name = entry['path']

destination = install_location full_name, destination_dir

file_data = ''

read_until_dashes io do |line|
          file_data << line
        end

file_data = file_data.strip.unpack("m")[0]
        file_data = Zlib::Inflate.inflate file_data

raise Gem::Package::FormatError, "#{full_name} in #{@gem} is corrupt" if
          file_data.length != entry['size'].to_i

FileUtils.rm_rf destination

FileUtils.mkdir_p File.dirname destination

open destination, 'wb', entry['mode'] do |out|
          out.write file_data
        end

verbose destination
      end
    end
  rescue Zlib::DataError
    raise Gem::Exception, errstr
  end

##
  # Reads the file list section from the old-format gem +io+

def file_list io # :nodoc:
    header = ''

read_until_dashes io do |line|
      header << line
    end

Gem::SafeYAML.safe_load header
  end

##
  # Reads lines until a "---" separator is found

def read_until_dashes io # :nodoc:
    while (line = io.gets) && line.chomp.strip != "---" do
      yield line if block_given?
    end
  end

##
  # Skips the Ruby self-install header in +io+.

def skip_ruby io # :nodoc:
    loop do
      line = io.gets

return if line.chomp == '__END__'
      break unless line
    end

raise Gem::Exception, "Failed to find end of ruby script while reading gem"
  end

##
  # The specification for this gem

def spec
    verify

return @spec if @spec

yaml = ''

open @gem, 'rb' do |io|
      skip_ruby io
      read_until_dashes io do |line|
        yaml << line
      end
    end

yaml_error = if RUBY_VERSION < '1.9' then
                   YAML::ParseError
                 elsif YAML::ENGINE.yamler == 'syck' then
                   YAML::ParseError
                 else
                   YAML::SyntaxError
                 end

begin
      @spec = Gem::Specification.from_yaml yaml
    rescue yaml_error => e
      raise Gem::Exception, "Failed to parse gem specification out of gem file"
    end
  rescue ArgumentError => e
    raise Gem::Exception, "Failed to parse gem specification out of gem file"
  end

##
  # Raises an exception if a security policy that verifies data is active.
  # Old format gems cannot be verified as signed.

def verify
    return true unless @security_policy

raise Gem::Security::Exception,
          'old format gems do not contain signatures and cannot be verified' if
      @security_policy.verify_data

true
  end

end

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