* lib/rubygems*: Updated to RubyGems 2.0

* test/rubygems*:  ditto.

* common.mk (prelude):  Updated for RubyGems 2.0 source rearrangement.

* tool/change_maker.rb:  Allow invalid UTF-8 characters in source
  files.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@37976 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

8 files changed, 312 insertions, 469 deletions

diff --git a/lib/rubygems/package/digest_io.rb b/lib/rubygems/package/digest_io.rb
new file mode 100644
index 0000000000..f8bde0f557
--- /dev/null
+++ b/lib/rubygems/package/digest_io.rb
@@ -0,0 +1,64 @@
+##
+# IO wrapper that creates digests of contents written to the IO it wraps.
+
+class Gem::Package::DigestIO
+
+  ##
+  # Collected digests for wrapped writes.
+  #
+  #   {
+  #     'SHA1'   => #<OpenSSL::Digest: [...]>,
+  #     'SHA512' => #<OpenSSL::Digest: [...]>,
+  #   }
+
+  attr_reader :digests
+
+  ##
+  # Wraps +io+ and updates digest for each of the digest algorithms in
+  # the +digests+ Hash.  Returns the digests hash.  Example:
+  #
+  #   io = StringIO.new
+  #   digests = {
+  #     'SHA1'   => OpenSSL::Digest.new('SHA1'),
+  #     'SHA512' => OpenSSL::Digest.new('SHA512'),
+  #   }
+  #
+  #   Gem::Package::DigestIO.wrap io, digests do |digest_io|
+  #     digest_io.write "hello"
+  #   end
+  #
+  #   digests['SHA1'].hexdigest   #=> "aaf4c61d[...]"
+  #   digests['SHA512'].hexdigest #=> "9b71d224[...]"
+
+  def self.wrap io, digests
+    digest_io = new io, digests
+
+    yield digest_io
+
+    return digests
+  end
+
+  ##
+  # Creates a new DigestIO instance.  Using ::wrap is recommended, see the
+  # ::wrap documentation for documentation of +io+ and +digests+.
+
+  def initialize io, digests
+    @io = io
+    @digests = digests
+  end
+
+  ##
+  # Writes +data+ to the underlying IO and updates the digests
+
+  def write data
+    result = @io.write data
+
+    @digests.each do |_, digest|
+      digest << data
+    end
+
+    result
+  end
+
+end
+
diff --git a/lib/rubygems/package/f_sync_dir.rb b/lib/rubygems/package/f_sync_dir.rb
deleted file mode 100644
index f7eb7f3ce3..0000000000
--- a/lib/rubygems/package/f_sync_dir.rb
+++ /dev/null
@@ -1,23 +0,0 @@
-# -*- coding: utf-8 -*-
-#--
-# Copyright (C) 2004 Mauricio Julio Fernández Pradier
-# See LICENSE.txt for additional licensing information.
-#++
-
-module Gem::Package::FSyncDir
-
-  private
-
-  ##
-  # make sure this hits the disc
-
-  def fsync_dir(dirname)
-    dir = open dirname, 'r'
-    dir.fsync
-  rescue # ignore IOError if it's an unpatched (old) Ruby
-  ensure
-    dir.close if dir rescue nil
-  end
-
-end
-
diff --git a/lib/rubygems/package/old.rb b/lib/rubygems/package/old.rb
new file mode 100644
index 0000000000..552a5f3591
--- /dev/null
+++ b/lib/rubygems/package/old.rb
@@ -0,0 +1,147 @@
+#--
+# 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
+
+    @gem      = gem
+    @contents = nil
+    @spec     = nil
+  end
+
+  ##
+  # A list of file names contained in this gem
+
+  def contents
+    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
+    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
+
+        say destination if Gem.configuration.really_verbose
+      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
+
+    YAML.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
+    return @spec if @spec
+
+    yaml = ''
+
+    open @gem, 'rb' do |io|
+      skip_ruby io
+      read_until_dashes io do |line|
+        yaml << line
+      end
+    end
+
+    @spec = Gem::Specification.from_yaml yaml
+  rescue YAML::SyntaxError => e
+    raise Gem::Exception, "Failed to parse gem specification out of gem file"
+  rescue ArgumentError => e
+    raise Gem::Exception, "Failed to parse gem specification out of gem file"
+  end
+
+end
+
diff --git a/lib/rubygems/package/tar_header.rb b/lib/rubygems/package/tar_header.rb
index 4f923b9b5e..28da1db0b5 100644
--- a/lib/rubygems/package/tar_header.rb
+++ b/lib/rubygems/package/tar_header.rb
@@ -102,61 +102,24 @@ class Gem::Package::TarHeader
 
     fields = header.unpack UNPACK_FORMAT
 
-    name     = fields.shift
-    mode     = fields.shift.oct
-    uid      = fields.shift.oct
-    gid      = fields.shift.oct
-    size     = fields.shift.oct
-    mtime    = fields.shift.oct
-    checksum = fields.shift.oct
-    typeflag = fields.shift
-    linkname = fields.shift
-    magic    = fields.shift
-    version  = fields.shift.oct
-    uname    = fields.shift
-    gname    = fields.shift
-    devmajor = fields.shift.oct
-    devminor = fields.shift.oct
-    prefix   = fields.shift
-
-    new :name     => name,
-        :mode     => mode,
-        :uid      => uid,
-        :gid      => gid,
-        :size     => size,
-        :mtime    => mtime,
-        :checksum => checksum,
-        :typeflag => typeflag,
-        :linkname => linkname,
-        :magic    => magic,
-        :version  => version,
-        :uname    => uname,
-        :gname    => gname,
-        :devmajor => devmajor,
-        :devminor => devminor,
-        :prefix   => prefix,
-
-        :empty    => empty
-
-    # HACK unfactor for Rubinius
-    #new :name     => fields.shift,
-    #    :mode     => fields.shift.oct,
-    #    :uid      => fields.shift.oct,
-    #    :gid      => fields.shift.oct,
-    #    :size     => fields.shift.oct,
-    #    :mtime    => fields.shift.oct,
-    #    :checksum => fields.shift.oct,
-    #    :typeflag => fields.shift,
-    #    :linkname => fields.shift,
-    #    :magic    => fields.shift,
-    #    :version  => fields.shift.oct,
-    #    :uname    => fields.shift,
-    #    :gname    => fields.shift,
-    #    :devmajor => fields.shift.oct,
-    #    :devminor => fields.shift.oct,
-    #    :prefix   => fields.shift,
-
-    #    :empty => empty
+    new :name     => fields.shift,
+        :mode     => fields.shift.oct,
+        :uid      => fields.shift.oct,
+        :gid      => fields.shift.oct,
+        :size     => fields.shift.oct,
+        :mtime    => fields.shift.oct,
+        :checksum => fields.shift.oct,
+        :typeflag => fields.shift,
+        :linkname => fields.shift,
+        :magic    => fields.shift,
+        :version  => fields.shift.oct,
+        :uname    => fields.shift,
+        :gname    => fields.shift,
+        :devmajor => fields.shift.oct,
+        :devminor => fields.shift.oct,
+        :prefix   => fields.shift,
+
+        :empty => empty
   end
 
   ##
diff --git a/lib/rubygems/package/tar_input.rb b/lib/rubygems/package/tar_input.rb
deleted file mode 100644
index 77b4d698da..0000000000
--- a/lib/rubygems/package/tar_input.rb
+++ /dev/null
@@ -1,235 +0,0 @@
-# -*- coding: iso-8859-1 -*-
-#++
-# Copyright (C) 2004 Mauricio Julio Fernández Pradier
-# See LICENSE.txt for additional licensing information.
-#--
-
-require 'zlib'
-Gem.load_yaml
-
-class Gem::Package::TarInput
-
-  include Gem::Package::FSyncDir
-  include Enumerable
-
-  attr_reader :metadata
-
-  private_class_method :new
-
-  def self.open(io, security_policy = nil,  &block)
-    is = new io, security_policy
-
-    yield is
-  ensure
-    is.close if is
-  end
-
-  def initialize(io, security_policy = nil)
-    @io = io
-    @tarreader = Gem::Package::TarReader.new @io
-    has_meta = false
-
-    data_sig, meta_sig, data_dgst, meta_dgst = nil, nil, nil, nil
-    dgst_algo = security_policy ? Gem::Security::OPT[:dgst_algo] : nil
-
-    @tarreader.each do |entry|
-      case entry.full_name
-      when "metadata"
-        @metadata = load_gemspec entry.read
-        has_meta = true
-      when "metadata.gz"
-        begin
-          # if we have a security_policy, then pre-read the metadata file
-          # and calculate it's digest
-          sio = nil
-          if security_policy
-            Gem.ensure_ssl_available
-            sio = StringIO.new(entry.read)
-            meta_dgst = dgst_algo.digest(sio.string)
-            sio.rewind
-          end
-
-          # Ruby 1.8 doesn't have encoding and YAML is UTF-8
-          args = [sio || entry]
-          args << { :external_encoding => Encoding::UTF_8 } if
-            Object.const_defined?(:Encoding)
-
-          gzis = Zlib::GzipReader.new(*args)
-
-          # YAML wants an instance of IO
-          @metadata = load_gemspec(gzis)
-          has_meta = true
-        ensure
-          gzis.close unless gzis.nil?
-        end
-      when 'metadata.gz.sig'
-        meta_sig = entry.read
-      when 'data.tar.gz.sig'
-        data_sig = entry.read
-      when 'data.tar.gz'
-        if security_policy
-          Gem.ensure_ssl_available
-          data_dgst = dgst_algo.digest(entry.read)
-        end
-      end
-    end
-
-    if security_policy then
-      Gem.ensure_ssl_available
-
-      # map trust policy from string to actual class (or a serialized YAML
-      # file, if that exists)
-      if String === security_policy then
-        if Gem::Security::Policies.key? security_policy then
-          # load one of the pre-defined security policies
-          security_policy = Gem::Security::Policies[security_policy]
-        elsif File.exist? security_policy then
-          # FIXME: this doesn't work yet
-          security_policy = YAML.load File.read(security_policy)
-        else
-          raise Gem::Exception, "Unknown trust policy '#{security_policy}'"
-        end
-      end
-
-      if data_sig && data_dgst && meta_sig && meta_dgst then
-        # the user has a trust policy, and we have a signed gem
-        # file, so use the trust policy to verify the gem signature
-
-        begin
-          security_policy.verify_gem(data_sig, data_dgst, @metadata.cert_chain)
-        rescue Exception => e
-          raise "Couldn't verify data signature: #{e}"
-        end
-
-        begin
-          security_policy.verify_gem(meta_sig, meta_dgst, @metadata.cert_chain)
-        rescue Exception => e
-          raise "Couldn't verify metadata signature: #{e}"
-        end
-      elsif security_policy.only_signed
-        raise Gem::Exception, "Unsigned gem"
-      else
-        # FIXME: should display warning here (trust policy, but
-        # either unsigned or badly signed gem file)
-      end
-    end
-
-    @tarreader.rewind
-
-    unless has_meta then
-      path = io.path if io.respond_to? :path
-      error = Gem::Package::FormatError.new 'no metadata found', path
-      raise error
-    end
-  end
-
-  def close
-    @io.close
-    @tarreader.close
-  end
-
-  def each(&block)
-    @tarreader.each do |entry|
-      next unless entry.full_name == "data.tar.gz"
-      is = zipped_stream entry
-
-      begin
-        Gem::Package::TarReader.new is do |inner|
-          inner.each(&block)
-        end
-      ensure
-        is.close if is
-      end
-    end
-
-    @tarreader.rewind
-  end
-
-  def extract_entry(destdir, entry, expected_md5sum = nil)
-    if entry.directory? then
-      dest = File.join destdir, entry.full_name
-
-      if File.directory? dest then
-        FileUtils.chmod entry.header.mode, dest, :verbose => false
-      else
-        FileUtils.mkdir_p dest, :mode => entry.header.mode, :verbose => false
-      end
-
-      fsync_dir dest
-      fsync_dir File.join(dest, "..")
-
-      return
-    end
-
-    # it's a file
-    md5 = Digest::MD5.new if expected_md5sum
-    destdir = File.join destdir, File.dirname(entry.full_name)
-    FileUtils.mkdir_p destdir, :mode => 0755, :verbose => false
-    destfile = File.join destdir, File.basename(entry.full_name)
-    FileUtils.chmod 0600, destfile, :verbose => false rescue nil # Errno::ENOENT
-
-    open destfile, "wb", entry.header.mode do |os|
-      loop do
-        data = entry.read 4096
-        break unless data
-        # HACK shouldn't we check the MD5 before writing to disk?
-        md5 << data if expected_md5sum
-        os.write(data)
-      end
-
-      os.fsync
-    end
-
-    FileUtils.chmod entry.header.mode, destfile, :verbose => false
-    fsync_dir File.dirname(destfile)
-    fsync_dir File.join(File.dirname(destfile), "..")
-
-    if expected_md5sum && expected_md5sum != md5.hexdigest then
-      raise Gem::Package::BadCheckSum
-    end
-  end
-
-  # Attempt to YAML-load a gemspec from the given _io_ parameter.  Return
-  # nil if it fails.
-  def load_gemspec(io)
-    Gem::Specification.from_yaml io
-  rescue Gem::Exception
-    nil
-  end
-
-  ##
-  # Return an IO stream for the zipped entry.
-  #
-  # NOTE:  Originally this method used two approaches, Return a GZipReader
-  # directly, or read the GZipReader into a string and return a StringIO on
-  # the string.  The string IO approach was used for versions of ZLib before
-  # 1.2.1 to avoid buffer errors on windows machines.  Then we found that
-  # errors happened with 1.2.1 as well, so we changed the condition.  Then
-  # we discovered errors occurred with versions as late as 1.2.3.  At this
-  # point (after some benchmarking to show we weren't seriously crippling
-  # the unpacking speed) we threw our hands in the air and declared that
-  # this method would use the String IO approach on all platforms at all
-  # times.  And that's the way it is.
-  #
-  # Revisited.  Here's the beginning of the long story.
-  # http://osdir.com/ml/lang.ruby.gems.devel/2007-06/msg00045.html
-  #
-  # StringIO wraping has never worked as a workaround by definition.  Skipping
-  # initial 10 bytes and passing -MAX_WBITS to Zlib::Inflate luckily works as
-  # gzip reader, but it only works if the GZip header is 10 bytes long (see
-  # below) and it does not check inflated stream consistency (CRC value in the
-  # Gzip trailer.)
-  #
-  #   RubyGems generated Gzip Header: 10 bytes
-  #     magic(2) + method(1) + flag(1) + mtime(4) + exflag(1) + os(1) +
-  #     orig_name(0) + comment(0)
-  #
-  # Ideally, it must return a GZipReader without meaningless buffering.  We
-  # have lots of CRuby committers around so let's fix windows build when we
-  # received an error.
-  def zipped_stream(entry)
-    Zlib::GzipReader.new entry
-  end
-
-end
-
diff --git a/lib/rubygems/package/tar_output.rb b/lib/rubygems/package/tar_output.rb
deleted file mode 100644
index fdc8f4fb7c..0000000000
--- a/lib/rubygems/package/tar_output.rb
+++ /dev/null
@@ -1,146 +0,0 @@
-# -*- coding: utf-8 -*-
-#--
-# Copyright (C) 2004 Mauricio Julio Fernández Pradier
-# See LICENSE.txt for additional licensing information.
-#++
-
-##
-# TarOutput is a wrapper to TarWriter that builds gem-format tar file.
-#
-# Gem-format tar files contain the following files:
-# [data.tar.gz] A gzipped tar file containing the files that compose the gem
-#               which will be extracted into the gem/ dir on installation.
-# [metadata.gz] A YAML format Gem::Specification.
-# [data.tar.gz.sig] A signature for the gem's data.tar.gz.
-# [metadata.gz.sig] A signature for the gem's metadata.gz.
-#
-# See TarOutput::open for usage details.
-
-class Gem::Package::TarOutput
-
-  ##
-  # Creates a new TarOutput which will yield a TarWriter object for the
-  # data.tar.gz portion of a gem-format tar file.
-  #
-  # See #initialize for details on +io+ and +signer+.
-  #
-  # See #add_gem_contents for details on adding metadata to the tar file.
-
-  def self.open(io, signer = nil, &block) # :yield: data_tar_writer
-    tar_outputter = new io, signer
-    tar_outputter.add_gem_contents(&block)
-    tar_outputter.add_metadata
-    tar_outputter.add_signatures
-
-  ensure
-    tar_outputter.close
-  end
-
-  ##
-  # Creates a new TarOutput that will write a gem-format tar file to +io+.  If
-  # +signer+ is given, the data.tar.gz and metadata.gz will be signed and
-  # the signatures will be added to the tar file.
-
-  def initialize(io, signer)
-    @io = io
-    @signer = signer
-
-    @tar_writer = Gem::Package::TarWriter.new @io
-
-    @metadata = nil
-
-    @data_signature = nil
-    @meta_signature = nil
-  end
-
-  ##
-  # Yields a TarWriter for the data.tar.gz inside a gem-format tar file.
-  # The yielded TarWriter has been extended with a #metadata= method for
-  # attaching a YAML format Gem::Specification which will be written by
-  # add_metadata.
-
-  def add_gem_contents
-    @tar_writer.add_file "data.tar.gz", 0644 do |inner|
-      sio = @signer ? StringIO.new : nil
-      Zlib::GzipWriter.wrap(sio || inner) do |os|
-
-        Gem::Package::TarWriter.new os do |data_tar_writer|
-          # :stopdoc:
-          def data_tar_writer.metadata() @metadata end
-          def data_tar_writer.metadata=(metadata) @metadata = metadata end
-          # :startdoc:
-
-          yield data_tar_writer
-
-          @metadata = data_tar_writer.metadata
-        end
-      end
-
-      # if we have a signing key, then sign the data
-      # digest and return the signature
-      if @signer then
-        require 'rubygems/security'
-        digest = Gem::Security::OPT[:dgst_algo].digest sio.string
-        @data_signature = @signer.sign digest
-        inner.write sio.string
-      end
-    end
-
-    self
-  end
-
-  ##
-  # Adds metadata.gz to the gem-format tar file which was saved from a
-  # previous #add_gem_contents call.
-
-  def add_metadata
-    return if @metadata.nil?
-
-    @tar_writer.add_file "metadata.gz", 0644 do |io|
-      begin
-        sio = @signer ? StringIO.new : nil
-        gzos = Zlib::GzipWriter.new(sio || io)
-        gzos.write @metadata
-      ensure
-        gzos.flush
-        gzos.finish
-
-        # if we have a signing key, then sign the metadata digest and return
-        # the signature
-        if @signer then
-          require 'rubygems/security'
-          digest = Gem::Security::OPT[:dgst_algo].digest sio.string
-          @meta_signature = @signer.sign digest
-          io.write sio.string
-        end
-      end
-    end
-  end
-
-  ##
-  # Adds data.tar.gz.sig and metadata.gz.sig to the gem-format tar files if
-  # a Gem::Security::Signer was sent to initialize.
-
-  def add_signatures
-    if @data_signature then
-      @tar_writer.add_file 'data.tar.gz.sig', 0644 do |io|
-        io.write @data_signature
-      end
-    end
-
-    if @meta_signature then
-      @tar_writer.add_file 'metadata.gz.sig', 0644 do |io|
-        io.write @meta_signature
-      end
-    end
-  end
-
-  ##
-  # Closes the TarOutput.
-
-  def close
-    @tar_writer.close
-  end
-
-end
-
diff --git a/lib/rubygems/package/tar_reader.rb b/lib/rubygems/package/tar_reader.rb
index e6a71d386c..e257fdd846 100644
--- a/lib/rubygems/package/tar_reader.rb
+++ b/lib/rubygems/package/tar_reader.rb
@@ -9,7 +9,7 @@
 
 class Gem::Package::TarReader
 
-  include Gem::Package
+  include Enumerable
 
   ##
   # Raised if the tar IO is not seekable
@@ -52,9 +52,9 @@ class Gem::Package::TarReader
   # Iterates over files in the tarball yielding each entry
 
   def each
-    loop do
-      return if @io.eof?
+    return enum_for __method__ unless block_given?
 
+    until @io.eof? do
       header = Gem::Package::TarHeader.from @io
       return if header.empty?
 
@@ -100,6 +100,23 @@ class Gem::Package::TarReader
     end
   end
 
+  ##
+  # Seeks through the tar file until it finds the +entry+ with +name+ and
+  # yields it.  Rewinds the tar file to the beginning when the block
+  # terminates.
+
+  def seek name # :yields: entry
+    found = find do |entry|
+      entry.full_name == name
+    end
+
+    return unless found
+
+    return yield found
+  ensure
+    rewind
+  end
+
 end
 
 require 'rubygems/package/tar_reader/entry'
diff --git a/lib/rubygems/package/tar_writer.rb b/lib/rubygems/package/tar_writer.rb
index a73b5e5cab..f2c11e3544 100644
--- a/lib/rubygems/package/tar_writer.rb
+++ b/lib/rubygems/package/tar_writer.rb
@@ -40,12 +40,12 @@ class Gem::Package::TarWriter
     # number of bytes will be more than #limit
 
     def write(data)
-      if data.size + @written > @limit
+      if data.bytesize + @written > @limit
         raise FileOverflow, "You tried to feed more data than fits in the file."
       end
       @io.write data
-      @written += data.size
-      data.size
+      @written += data.bytesize
+      data.bytesize
     end
 
   end
@@ -130,6 +130,62 @@ class Gem::Package::TarWriter
   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, 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,
+      OpenSSL::Digest::SHA512,
+    ].uniq
+
+    digests = add_file_digest name, mode, digest_algorithms do |io|
+      yield io
+    end
+
+    signature_digest = digests.values.find do |digest|
+      digest.name == signer.digest_name
+    end
+
+    signature = signer.sign signature_digest.digest
+
+    add_file_simple "#{name}.sig", 0444, signature.length do |io|
+      io.write signature
+    end if signature
+
+    digests
+  end
+
+  ##
   # Add file +name+ with permissions +mode+ +size+ bytes long.  Yields an IO
   # to write the file to.
 
@@ -211,9 +267,9 @@ class Gem::Package::TarWriter
   # 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
+    raise Gem::Package::TooLongFileName if name.bytesize > 256
 
-    if name.size <= 100 then
+    if name.bytesize <= 100 then
       prefix = ""
     else
       parts = name.split(/\//)
@@ -222,14 +278,14 @@ class Gem::Package::TarWriter
 
       loop do
         nxt = parts.pop
-        break if newname.size + 1 + nxt.size > 100
+        break if newname.bytesize + 1 + nxt.bytesize > 100
         newname = nxt + "/" + newname
       end
 
       prefix = (parts + [nxt]).join "/"
       name = newname
 
-      if name.size > 100 or prefix.size > 155 then
+      if name.bytesize > 100 or prefix.bytesize > 155 then
         raise Gem::Package::TooLongFileName
       end
     end