module Archive::Tar::Minitar

Synopsis

Using minitar is easy. The simplest case is:

require 'zlib'
require 'minitar'

# Packs everything that matches Find.find('tests').
# test.tar will automatically be closed by Minitar.pack.
Minitar.pack('tests', File.open('test.tar', 'wb'))

# Unpacks 'test.tar' to 'x', creating 'x' if necessary.
Minitar.unpack('test.tar', 'x')

A gzipped tar can be written with:

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

# test.tgz will be closed automatically.
Minitar.unpack(Zlib::GzipReader.new(File.open('test.tgz', 'rb')), '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 Archive::Tar::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

Constants

ClosedStream: The exception raised when operations are performed on a stream that has previously been closed.
Error: The base class for any minitar error.
FileNameTooLong: The exception raised when a filename exceeds 256 bytes in length, the maximum supported by the standard Tar format.
NonSeekableStream: Raised when a wrapped data stream class is not seekable.
SecureRelativePathError: The exception raised when a file contains a relative path in secure mode (the default for this version).
UnexpectedEOF: The exception raised when a data stream ends before the amount of data expected in the archive’s PosixHeader.

Public Class Methods

dir?(path) click to toggle source

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

# File lib/archive/tar/minitar.rb, line 97
def dir?(path)
  # rubocop:disable Style/CharacterLiteral
  File.directory?(path[-1] == / ? path : "#{path}/")
  # rubocop:enable Style/CharacterLiteral
end

open(dest, mode = 'r', &block) click to toggle source

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/archive/tar/minitar.rb, line 106
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) click to toggle source

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 result of Find.find; all files matching will be packed.

# File lib/archive/tar/minitar.rb, line 221
def pack(src, dest, recurse_dirs = true, &block)
  require 'find'
  Output.open(dest) do |outp|
    if src.kind_of?(Array)
      src.each do |entry|
        if dir?(entry) and recurse_dirs
          Find.find(entry) do |ee|
            pack_file(ee, outp, &block)
          end
        else
          pack_file(entry, outp, &block)
        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| ... } click to toggle source

A convenience method to pack 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 archive. 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/archive/tar/minitar.rb, line 165
def pack_file(entry, outputter) #:yields action, name, stats:
  if outputter.kind_of?(Archive::Tar::Minitar::Output)
    outputter = outputter.tar
  end

  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 windows?
    stats[:uid]  = nil
    stats[:gid]  = nil
  else
    stats[:uid]  ||= stat.uid
    stats[:gid]  ||= stat.gid
  end

  if 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
  elsif dir?(name)
    yield :dir, name, stats if block_given?
    outputter.mkdir(name, stats)
  else
    raise %q(Don't yet know how to pack this type of file.)
  end
end

seekable?(io, methods = nil) click to toggle source

Check whether io can seek without errors.

# File lib/archive/tar/minitar.rb, line 262
def seekable?(io, methods = nil)
  # The IO class throws an exception at runtime if we try to change
  # position on a non-regular file.
  if io.respond_to?(:stat)
    io.stat.file?
  else
    # Duck-type the rest of this.
    methods ||= [ :pos, :pos=, :seek, :rewind ]
    methods = [ methods ] unless methods.kind_of?(Array)
    methods.all? { |m| io.respond_to?(m) }
  end
end

unpack(src, dest, files = [], &block) click to toggle source

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/archive/tar/minitar.rb, line 245
def unpack(src, dest, files = [], &block)
  Input.open(src) do |inp|
    if File.exist?(dest) and !dir?(dest)
      raise %q(Can't unpack to a non-directory.)
    end

    FileUtils.mkdir_p(dest) unless File.exist?(dest)

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