class Tar::Minitar::Writer

The class that writes a tar format archive to a data stream.

Constants

WriteBoundaryOverflow

The exception raised when the user attempts to write more data to a BoundedWriteStream than has been allocated.

Public Class Methods

const_missing(c) click to toggle source
Calls superclass method
# File lib/archive/tar/minitar/writer.rb, line 65
def self.const_missing(c)
  case c
  when :BoundedStream
    warn 'BoundedStream has been renamed to BoundedWriteStream'
    const_set(:BoundedStream, BoundedWriteStream)
  else
    super
  end
end
new(io) click to toggle source

Creates and returns a new Writer object.

# File lib/archive/tar/minitar/writer.rb, line 103
def initialize(io)
  @io     = io
  @closed = false
end
w = Archive::Tar::Minitar::Writer.open(STDOUT) click to toggle source
add_file_simple('foo.txt', :size → 3)
close

With no associated block, Writer::open is a synonym for Writer::new. If the optional code block is given, it will be passed the new writer as an argument and the Writer object will automatically be closed when the block terminates. In this instance, Writer::open returns the value of the block.

Archive::Tar::Minitar::Writer.open(STDOUT) do |w|
  w.add_file_simple('foo.txt', :size => 3)
end
# File lib/archive/tar/minitar/writer.rb, line 89
def self.open(io) # :yields Writer:
  writer = new(io)
  return writer unless block_given?

  # This exception context must remain, otherwise the stream closes on open
  # even if a block is not given.
  begin
    yield writer
  ensure
    writer.close
  end
end

Public Instance Methods

add_file(name, opts = {}) { |write_only_stream, opts| ... } click to toggle source

Adds a file to the archive as name. The data can be provided in the opts[:data] or provided to a yielded WriteOnlyStream. The size of the file will be determined from the amount of data written to the stream.

Valid parameters to opts are:

:mode

The Unix file permissions mode value. If not provided, defaults to 0644.

:uid

The Unix file owner user ID number.

:gid

The Unix file owner group ID number.

:mtime

File modification time, interpreted as an integer.

:data

Optional. The data to write to the archive.

If opts[:data] is provided, this acts the same as add_file_simple. Otherwise, the file’s size will be determined from the amount of data written to the stream.

For add_file to be used without opts[:data], the Writer must be wrapping a stream object that is seekable. Otherwise, add_file_simple must be used.

opts may be modified during the writing of the file to the stream.

# File lib/archive/tar/minitar/writer.rb, line 205
def add_file(name, opts = {}, &block) # :yields WriteOnlyStream, +opts+:
  raise ClosedStream if @closed

  return add_file_simple(name, opts, &block) if opts[:data]

  unless Archive::Tar::Minitar.seekable?(@io)
    raise Archive::Tar::Minitar::NonSeekableStream
  end

  init_pos = @io.pos
  @io.write("\0" * 512) # placeholder for the header

  yield WriteOnlyStream.new(@io), opts

  size      = @io.pos - (init_pos + 512)
  remainder = (512 - (size % 512)) % 512
  @io.write("\0" * remainder)

  final_pos, @io.pos = @io.pos, init_pos

  header = {
    :mode => opts[:mode],
    :mtime => opts[:mtime],
    :size => size,
    :gid => opts[:gid],
    :uid => opts[:uid],
  }
  write_header(name, header)
  @io.pos = final_pos
end
add_file_simple('foo.txt', :data → "bar") click to toggle source
add_file_simple('foo.txt', :size → 3) do |w|
write("bar")
end

Adds a file to the archive as name. The data can be provided in the opts[:data] or provided to a BoundedWriteStream that is yielded to the provided block.

If opts[:data] is provided, all other values to opts are optional. If the data is provided to the yielded BoundedWriteStream, opts[:size] must be provided.

Valid parameters to opts are:

:data

Optional. The data to write to the archive.

:mode

The Unix file permissions mode value. If not provided, defaults to 0644.

:size

The size, in bytes. If :data is provided, this parameter may be ignored (if it is less than the size of the data provided) or used to add padding (if it is greater than the size of the data provided).

:uid

The Unix file owner user ID number.

:gid

The Unix file owner group ID number.

:mtime

File modification time, interpreted as an integer.

An exception will be raised if the Writer is already closed, or if more data is written to the BoundedWriteStream than expected.

# File lib/archive/tar/minitar/writer.rb, line 138
def add_file_simple(name, opts = {}) # :yields BoundedWriteStream:
  raise ClosedStream if @closed

  header = {
    :mode   => opts.fetch(:mode, 0o644),
    :mtime  => opts.fetch(:mtime, nil),
    :gid    => opts.fetch(:gid, nil),
    :uid    => opts.fetch(:uid, nil)
  }

  data = opts.fetch(:data, nil)
  size = opts.fetch(:size, nil)

  if block_given?
    if data
      raise ArgumentError,
        'Too much data (opts[:data] and block_given?).'
    end

    raise ArgumentError, 'No size provided' unless size
  else
    raise ArgumentError, 'No data provided' unless data

    bytes = bytesize(data)
    size = bytes if size.nil? || size < bytes
  end

  header[:size] = size

  write_header(name, header)

  os = BoundedWriteStream.new(@io, size)
  if block_given?
    yield os
  else
    os.write(data)
  end

  min_padding = size - os.written
  @io.write("\0" * min_padding)
  remainder = (512 - (size % 512)) % 512
  @io.write("\0" * remainder)
end
close() click to toggle source

Closes the Writer. This does not close the underlying wrapped output stream.

# File lib/archive/tar/minitar/writer.rb, line 266
def close
  return if @closed
  @io.write("\0" * 1024)
  @closed = true
end
closed?() click to toggle source

Returns false if the writer is open.

# File lib/archive/tar/minitar/writer.rb, line 260
def closed?
  @closed
end
flush() click to toggle source

Passes the flush method to the wrapped stream, used for buffered streams.

# File lib/archive/tar/minitar/writer.rb, line 254
def flush
  raise ClosedStream if @closed
  @io.flush if @io.respond_to?(:flush)
end
mkdir(name, opts = {}) click to toggle source

Creates a directory entry in the tar.

# File lib/archive/tar/minitar/writer.rb, line 237
def mkdir(name, opts = {})
  raise ClosedStream if @closed

  header = {
    :mode => opts[:mode],
    :typeflag => '5',
    :size => 0,
    :gid => opts[:gid],
    :uid => opts[:uid],
    :mtime => opts[:mtime],
  }
  write_header(name, header)
  nil
end

Private Instance Methods

split_name(name) click to toggle source
# File lib/archive/tar/minitar/writer.rb, line 294
def split_name(name)
  if bytesize(name) <= 100
    prefix = ''
  else
    parts = name.split(/\//)
    newname = parts.pop

    nxt = ''

    loop do
      nxt = parts.pop || ''
      break if bytesize(newname) + 1 + bytesize(nxt) >= 100
      newname = "#{nxt}/#{newname}"
    end

    prefix = (parts + [nxt]).join('/')

    name = newname
  end

  [ name, prefix, (bytesize(name) > 100 || bytesize(prefix) > 155) ]
end
write_header(long_name, header) click to toggle source
# File lib/archive/tar/minitar/writer.rb, line 274
def write_header(long_name, header)
  short_name, prefix, needs_long_name = split_name(long_name)

  if needs_long_name
    long_name_header = {
      :prefix => '',
      :name => PosixHeader::GNU_EXT_LONG_LINK,
      :typeflag => 'L',
      :size => long_name.length,
      :mode => 0,
    }
    @io.write(PosixHeader.new(long_name_header))
    @io.write(long_name)
    @io.write("\0" * (512 - (long_name.length % 512)))
  end

  new_header = header.merge({ :name => short_name, :prefix => prefix })
  @io.write(PosixHeader.new(new_header))
end