Archive::Tar::Minitar 0.5.1

Archive::Tar::Minitar is a pure-Ruby library and command-line utility that provides the ability to deal with POSIX tar(1) archive files. The implementation is based heavily on Mauricio Fern�dez‘s implementation in rpa-base, but has been reorganised to promote reuse in other projects.

This tar class performs a subset of all tar (POSIX tape archive) operations. We can only deal with typeflags 0, 1, 2, and 5 (see Archive::Tar::PosixHeader). All other typeflags will be treated as normal files.

NOTE::

support for typeflags 1 and 2 is not yet implemented in this version.

This release is version 0.5.1. The library can only handle files and directories at this point. A future version will be expanded to handle symbolic links and hard links in a portable manner. The command line utility, minitar, can only create archives, extract from archives, and list archive contents.

Synopsis

Using this library is easy. The simplest case is:

  require 'zlib'
  require 'archive/tar/minitar'
  include Archive::Tar

    # Packs everything that matches Find.find('tests')
  File.open('test.tar', 'wb') { |tar| Minitar.pack('tests', tar) }
    # Unpacks 'test.tar' to 'x', creating 'x' if necessary.
  Minitar.unpack('test.tar', 'x')

A gzipped tar can be written with:

  tgz = Zlib::GzipWriter.new(File.open('test.tgz', 'wb'))
    # Warning: tgz will be closed!
  Minitar.pack('tests', tgz)

  tgz = Zlib::GzipReader.new(File.open('test.tgz', 'rb'))
    # Warning: tgz will be closed!
  Minitar.unpack(tgz, 'x')

As the case above shows, one need not write to a file. However, it will sometimes require that one dive a little deeper into the API, as in the case of StringIO objects. Note that I‘m not providing a block with Minitar::Output, as Minitar::Output#close automatically closes both the Output object and the wrapped data stream object.

  begin
    sgz = Zlib::GzipWriter.new(StringIO.new(""))
    tar = Output.new(sgz)
    Find.find('tests') do |entry|
      Minitar.pack_file(entry, tar)
    end
  ensure
      # Closes both tar and sgz.
    tar.close
  end

Copyright

This program is based on and incorporates parts of RPA::Package from rpa-base (lib/rpa/package.rb and lib/rpa/util.rb) by Mauricio and has been adapted to be more generic by Austin.

This program is free software. It may be redistributed and/or modified under the terms of the GPL version 2 (or later) or Ruby‘s licence.

Methods

dir? open pack pack_file unpack

Classes and Modules

Class Archive::Tar::Minitar::Input
Class Archive::Tar::Minitar::Output
Class Archive::Tar::Minitar::Reader
Class Archive::Tar::Minitar::Writer

Constants

VERSION

"0.5.1"

Public Class methods

dir?(path)

Tests if path refers to a directory. Fixes an apparently corrupted stat() call on Windows.

[ + ]

# File lib/more/facets/minitar.rb, line 914
    def dir?(path)
      File.directory?((path[-1] == ?/) ? path : "#{path}/")
    end

open(dest, mode = "r", &block)

A convenience method for wrapping Archive::Tar::Minitar::Input.open (mode r) and Archive::Tar::Minitar::Output.open (mode w). No other modes are currently supported.

[ + ]

# File lib/more/facets/minitar.rb, line 921
    def open(dest, mode = "r", &block)
      case mode
      when "r"
        Input.open(dest, &block)
      when "w"
        Output.open(dest, &block)
      else
        raise "Unknown open mode for Archive::Tar::Minitar.open."
      end
    end

pack(src, dest, recurse_dirs = true, &block)

A convenience method to pack files specified by src into dest. If src is an Array, then each file detailed therein will be packed into the resulting Archive::Tar::Minitar::Output stream; if recurse_dirs is true, then directories will be recursed.

If src is an Array, it will be treated as the argument to Find.find; all files matching will be packed.

[ + ]

# File lib/more/facets/minitar.rb, line 1023
    def pack(src, dest, recurse_dirs = true, &block)
      Output.open(dest) do |outp|
        if src.kind_of?(Array)
          src.each do |entry|
            pack_file(entry, outp, &block)
            if dir?(entry) and recurse_dirs
              Dir["#{entry}/**/**"].each do |ee|
                pack_file(ee, outp, &block)
              end
            end
          end
        else
          Find.find(src) do |entry|
            pack_file(entry, outp, &block)
          end
        end
      end
    end

pack_file(entry, outputter) {|:file_start, name, stats if block_given?| ...}

A convenience method to packs the file provided. entry may either be a filename (in which case various values for the file (see below) will be obtained from File#stat(entry) or a Hash with the fields:

`:name`:	The filename to be packed into the tarchive. REQUIRED.
`:mode`:	The mode to be applied.
`:uid`:	The user owner of the file. (Ignored on Windows.)
`:gid`:	The group owner of the file. (Ignored on Windows.)
`:mtime`:	The modification Time of the file.

During packing, if a block is provided, pack_file yields an action Symol, the full name of the file being packed, and a Hash of statistical information, just as with Archive::Tar::Minitar::Input#extract_entry.

The action will be one of:

`:dir`:	The `entry` is a directory.
`:file_start`:	The `entry` is a file; the extract of the file is just beginning.
`:file_progress`:	Yielded every 4096 bytes during the extract of the `entry`.
`:file_done`:	Yielded when the `entry` is completed.

The stats hash contains the following keys:

`:current`:	The current total number of bytes read in the `entry`.
`:currinc`:	The current number of bytes read in this read cycle.
`:name`:	The filename to be packed into the tarchive. REQUIRED.
`:mode`:	The mode to be applied.
`:uid`:	The user owner of the file. (`nil` on Windows.)
`:gid`:	The group owner of the file. (`nil` on Windows.)
`:mtime`:	The modification Time of the file.

[ + ]

# File lib/more/facets/minitar.rb, line 967
    def pack_file(entry, outputter) #:yields action, name, stats:
      outputter = outputter.tar if outputter.kind_of?(Archive::Tar::Minitar::Output)

      stats = {}

      if entry.kind_of?(Hash)
        name = entry[:name]

        entry.each { |kk, vv| stats[kk] = vv unless vv.nil? }
      else
        name = entry
      end

      name = name.sub(%r{\./}, '')
      stat = File.stat(name)
      stats[:mode]   ||= stat.mode
      stats[:mtime]  ||= stat.mtime
      stats[:size]   = stat.size

      if RUBY_PLATFORM =~ /win32/
        stats[:uid]  = nil
        stats[:gid]  = nil
      else
        stats[:uid]  ||= stat.uid
        stats[:gid]  ||= stat.gid
      end

      case
      when File.file?(name)
        outputter.add_file_simple(name, stats) do |os|
          stats[:current] = 0
          yield :file_start, name, stats if block_given?
          File.open(name, "rb") do |ff|
            until ff.eof?
              stats[:currinc] = os.write(ff.read(4096))
              stats[:current] += stats[:currinc]
              yield :file_progress, name, stats if block_given?
            end
          end
          yield :file_done, name, stats if block_given?
        end
      when dir?(name)
        yield :dir, name, stats if block_given?
        outputter.mkdir(name, stats)
      else
        raise "Don't yet know how to pack this type of file."
      end
    end

unpack(src, dest, files = [], &block)

A convenience method to unpack files from src into the directory specified by dest. Only those files named explicitly in files will be extracted.

[ + ]

# File lib/more/facets/minitar.rb, line 1045
    def unpack(src, dest, files = [], &block)
      Input.open(src) do |inp|
        if File.exist?(dest) and (not dir?(dest))
          raise "Can't unpack to a non-directory."
        elsif not File.exist?(dest)
          FileUtils.mkdir_p(dest)
        end

        inp.each do |entry|
          if files.empty? or files.include?(entry.full_name)
            inp.extract_entry(dest, entry, &block)
          end
        end
      end
    end