JezK
Edit File: tar_writer.rb
# -*- coding: utf-8 -*- # frozen_string_literal: true #-- # Copyright (C) 2004 Mauricio Julio Fernández Pradier # See LICENSE.txt for additional licensing information. #++ require 'digest' ## # 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.bytesize + @written > @limit raise FileOverflow, "You tried to feed more data than fits in the file." end @io.write data @written += data.bytesize data.bytesize 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 name, prefix = split_name name init_pos = @io.pos @io.write Gem::Package::TarHeader::EMPTY_HEADER # 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, :mtime => Gem.source_date_epoch @io.write header @io.pos = final_pos self end ## # Adds +name+ with permissions +mode+ to the tar, yielding +io+ for writing # the file. The +digest_algorithm+ is written to a read-only +name+.sum # file following the given file contents containing the digest name and # hexdigest separated by a tab. # # The created digest object is returned. def add_file_digest(name, mode, digest_algorithms) # :yields: io digests = digest_algorithms.map do |digest_algorithm| digest = digest_algorithm.new digest_name = if digest.respond_to? :name digest.name else /::([^:]+)$/ =~ digest_algorithm.name $1 end [digest_name, digest] end digests = Hash[*digests.flatten] add_file name, mode do |io| Gem::Package::DigestIO.wrap io, digests do |digest_io| yield digest_io end end digests end ## # Adds +name+ with permissions +mode+ to the tar, yielding +io+ for writing # the file. The +signer+ is used to add a digest file using its # digest_algorithm per add_file_digest and a cryptographic signature in # +name+.sig. If the signer has no key only the checksum file is added. # # Returns the digest. def add_file_signed(name, mode, signer) digest_algorithms = [ signer.digest_algorithm, Digest::SHA512, ].compact.uniq digests = add_file_digest name, mode, digest_algorithms do |io| yield io end signature_digest = digests.values.compact.find do |digest| digest_name = if digest.respond_to? :name digest.name else digest.class.name[/::([^:]+)\z/, 1] end digest_name == signer.digest_name end raise "no #{signer.digest_name} in #{digests.values.compact}" unless signature_digest if signer.key signature = signer.sign signature_digest.digest add_file_simple "#{name}.sig", 0444, signature.length do |io| io.write signature end end digests 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, :mtime => Gem.source_date_epoch).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 ## # Adds symlink +name+ with permissions +mode+, linking to +target+. def add_symlink(name, target, mode) check_closed name, prefix = split_name name header = Gem::Package::TarHeader.new(:name => name, :mode => mode, :size => 0, :typeflag => "2", :linkname => target, :prefix => prefix, :mtime => Gem.source_date_epoch).to_s @io.write header 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, :mtime => Gem.source_date_epoch @io.write header self end ## # Splits +name+ into a name and prefix that can fit in the TarHeader def split_name(name) # :nodoc: if name.bytesize > 256 raise Gem::Package::TooLongFileName.new("File \"#{name}\" has a too long path (should be 256 or less)") end prefix = '' if name.bytesize > 100 parts = name.split('/', -1) # parts are never empty here name = parts.pop # initially empty for names with a trailing slash ("foo/.../bar/") prefix = parts.join('/') # if empty, then it's impossible to split (parts is empty too) while !parts.empty? && (prefix.bytesize > 155 || name.empty?) name = parts.pop + '/' + name prefix = parts.join('/') end if name.bytesize > 100 or prefix.empty? raise Gem::Package::TooLongFileName.new("File \"#{prefix}/#{name}\" has a too long name (should be 100 or less)") end if prefix.bytesize > 155 raise Gem::Package::TooLongFileName.new("File \"#{prefix}/#{name}\" has a too long base path (should be 155 or less)") end end return name, prefix end end