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Class: Gem::Package::TarReader

Relationships & Source Files
Namespace Children
Classes:
Entry
Exceptions:
UnexpectedEOF
Super Chains via Extension / Inclusion / Inheritance
Instance Chain:
self, Enumerable
Inherits: Object
Defined in: lib/rubygems/package/tar_reader.rb

Overview

TarReader reads tar files and allows iteration over their items

Class Method Summary

Instance Method Summary

Constructor Details

.new(io) ⇒ TarReader

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

[ GitHub ] 

  


# File 'lib/rubygems/package/tar_reader.rb', line 23



def self.new(io)
  reader = super

  return reader unless block_given?

  begin
    yield reader
  ensure
    reader.close
  end

  nil
end


  






  

  

    #initialize(io)  ⇒ TarReader 
  



  

    

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


  





  


  [ GitHub ]


  

  


# File 'lib/rubygems/package/tar_reader.rb', line 41



def initialize(io)
  @io = io
  @init_pos = io.pos
end


  







Instance Method Details



  

    #close  
  



  

    

Close the tar file


  



  [ GitHub ]


  

  


# File 'lib/rubygems/package/tar_reader.rb', line 49



def close
end


  








  

    #each  
    Also known as: #each_entry
  



  

    

Iterates over files in the tarball yielding each entry


  



  [ GitHub ]


  

  


# File 'lib/rubygems/package/tar_reader.rb', line 55



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


  








  

    #each_entry  
  



  

    

Alias for #each.


  



  [ GitHub ]


  

  


# File 'lib/rubygems/package/tar_reader.rb', line 95



alias each_entry each


  








  

    #rewind  
  



  

    

NOTE: Do not call #rewind during #each


  



  [ GitHub ]


  

  


# File 'lib/rubygems/package/tar_reader.rb', line 100



def rewind
  if @init_pos == 0
    @io.rewind
  else
    @io.pos = @init_pos
  end
end


  








  

    #seek(name)  
  



  

    

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.


  



  [ GitHub ]


  

  


# File 'lib/rubygems/package/tar_reader.rb', line 113



def seek(name) # :yields: entry
  found = find do |entry|
    entry.full_name == name
  end

  return unless found

  return yield found
ensure
  rewind
end