Gem::Package::TarReader

TarReader reads tar files and allows iteration over their items

Public Class Methods

new(io) click to toggle source

Creates a new TarReader on io and yields it to the block, if given.

 
               # File rubygems/package/tar_reader.rb, line 21
def self.new(io)
  reader = super

  return reader unless block_given?

  begin
    yield reader
  ensure
    reader.close
  end

  nil
end

new(io) click to toggle source

Creates a new tar file reader on io which needs to respond to pos, eof?, read, getc and pos=

 
               # File rubygems/package/tar_reader.rb, line 39
def initialize(io)
  @io = io
  @init_pos = io.pos
end

Public Instance Methods

close() click to toggle source

Close the tar file

 
               # File rubygems/package/tar_reader.rb, line 47
def close
end

each() click to toggle source

Iterates over files in the tarball yielding each entry

 
               # File rubygems/package/tar_reader.rb, line 53
def each
  return enum_for __method__ unless block_given?

  use_seek = @io.respond_to?(:seek)

  until @io.eof? do
    header = Gem::Package::TarHeader.from @io
    return if header.empty?

    entry = Gem::Package::TarReader::Entry.new header, @io
    size = entry.header.size

    yield entry

    skip = (512 - (size % 512)) % 512
    pending = size - entry.bytes_read

    if use_seek
      begin
        # avoid reading if the @io supports seeking
        @io.seek pending, IO::SEEK_CUR
        pending = 0
      rescue Errno::EINVAL
      end
    end

    # if seeking isn't supported or failed
    while pending > 0 do
      bytes_read = @io.read([pending, 4096].min).size
      raise UnexpectedEOF if @io.eof?
      pending -= bytes_read
    end

    @io.read skip # discard trailing zeros

    # make sure nobody can use #read, #getc or #rewind anymore
    entry.close
  end
end

Also aliased as: each_entry

each_entry() click to toggle source

Alias for: each

rewind() click to toggle source

NOTE: Do not call rewind during each

 
               # File rubygems/package/tar_reader.rb, line 98
def rewind
  if @init_pos == 0
    @io.rewind
  else
    @io.pos = @init_pos
  end
end

seek(name) click to toggle source

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.

 
               # File rubygems/package/tar_reader.rb, line 111
def seek(name) # :yields: entry
  found = find do |entry|
    entry.full_name == name
  end

  return unless found

  return yield found
ensure
  rewind
end