Class: Gem::Package::TarHeader
Relationships & Source Files | |
Inherits: | Object |
Defined in: | lib/rubygems/package/tar_header.rb |
Overview
A header for a tar file
Constant Summary
-
FIELDS =
Fields in the tar header
[ :checksum, :devmajor, :devminor, :gid, :gname, :linkname, :magic, :mode, :mtime, :name, :prefix, :size, :typeflag, :uid, :uname, :version, ]
-
PACK_FORMAT =
Pack format for a tar header
'a100' + # name 'a8' + # mode 'a8' + # uid 'a8' + # gid 'a12' + # size 'a12' + # mtime 'a7a' + # chksum 'a' + # typeflag 'a100' + # linkname 'a6' + # magic 'a2' + # version 'a32' + # uname 'a32' + # gname 'a8' + # devmajor 'a8' + # devminor 'a155'
-
UNPACK_FORMAT =
Unpack format for a tar header
'A100' + # name 'A8' + # mode 'A8' + # uid 'A8' + # gid 'A12' + # size 'A12' + # mtime 'A8' + # checksum 'A' + # typeflag 'A100' + # linkname 'A6' + # magic 'A2' + # version 'A32' + # uname 'A32' + # gname 'A8' + # devmajor 'A8' + # devminor 'A155'
Class Method Summary
-
.from(stream)
Creates a tar header from IO
stream
-
.new(vals) ⇒ TarHeader
constructor
Creates a new
TarHeader
usingvals
- .strict_oct(str)
Instance Attribute Summary
-
#empty? ⇒ Boolean
readonly
Is the tar entry empty?
Instance Method Summary
-
#update_checksum
Updates the TarHeader's checksum.
- #calculate_checksum(header) private
- #header(checksum = @checksum) private
- #oct(num, len) private
Constructor Details
.new(vals) ⇒ TarHeader
Creates a new TarHeader
using vals
# File 'lib/rubygems/package/tar_header.rb', line 134
def initialize(vals) unless vals[:name] && vals[:size] && vals[:prefix] && vals[:mode] then raise ArgumentError, ":name, :size, :prefix and :mode required" end vals[:uid] ||= 0 vals[:gid] ||= 0 vals[:mtime] ||= 0 vals[:checksum] ||= "" vals[:typeflag] = "0" if vals[:typeflag].nil? || vals[:typeflag].empty? vals[:magic] ||= "ustar" vals[:version] ||= "00" vals[:uname] ||= "wheel" vals[:gname] ||= "wheel" vals[:devmajor] ||= 0 vals[:devminor] ||= 0 FIELDS.each do |name| instance_variable_set "@#{name}", vals[name] end @empty = vals[:empty] end
Class Method Details
.from(stream)
Creates a tar header from IO stream
# File 'lib/rubygems/package/tar_header.rb', line 100
def self.from(stream) header = stream.read 512 empty = (header == "\0" * 512) fields = header.unpack UNPACK_FORMAT new :name => fields.shift, :mode => strict_oct(fields.shift), :uid => strict_oct(fields.shift), :gid => strict_oct(fields.shift), :size => strict_oct(fields.shift), :mtime => strict_oct(fields.shift), :checksum => strict_oct(fields.shift), :typeflag => fields.shift, :linkname => fields.shift, :magic => fields.shift, :version => strict_oct(fields.shift), :uname => fields.shift, :gname => fields.shift, :devmajor => strict_oct(fields.shift), :devminor => strict_oct(fields.shift), :prefix => fields.shift, :empty => empty end
.strict_oct(str)
# File 'lib/rubygems/package/tar_header.rb', line 126
def self.strict_oct(str) return str.oct if str =~ /\A[0-7]*\z/ raise ArgumentError, "#{str.inspect} is not an octal string" end
Instance Attribute Details
#empty? ⇒ Boolean
(readonly)
Is the tar entry empty?
# File 'lib/rubygems/package/tar_header.rb', line 161
def empty? @empty end
Instance Method Details
#calculate_checksum(header) (private)
[ GitHub ]#header(checksum = @checksum) (private)
[ GitHub ]# File 'lib/rubygems/package/tar_header.rb', line 204
def header(checksum = @checksum) header = [ name, oct(mode, 7), oct(uid, 7), oct(gid, 7), oct(size, 11), oct(mtime, 11), checksum, " ", typeflag, linkname, magic, oct(version, 2), uname, gname, oct(devmajor, 7), oct(devminor, 7), prefix ] header = header.pack PACK_FORMAT header << ("\0" * ((512 - header.size) % 512)) end
#oct(num, len) (private)
[ GitHub ]# File 'lib/rubygems/package/tar_header.rb', line 230
def oct(num, len) "%0#{len}o" % num end
#update_checksum
Updates the TarHeader's checksum
# File 'lib/rubygems/package/tar_header.rb', line 193
def update_checksum header = header " " * 8 @checksum = oct calculate_checksum(header), 6 end