Class: Gem::Package::TarReader::Entry

Inherits:
Object
  • Object
show all
Defined in:
lib/rubygems/package/tar_reader/entry.rb

Overview

Class for reading entries out of a tar file

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(header, io) ⇒ Entry

Creates a new tar entry for header that will be read from io



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# File 'lib/rubygems/package/tar_reader/entry.rb', line 36

def initialize(header, io)
  @closed = false
  @header = header
  @io = io
  @orig_pos = @io.pos
  @end_pos = @orig_pos + @header.size
  @read = 0
end

Instance Attribute Details

#header ⇒ Object (readonly)

Header for this tar entry



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# File 'lib/rubygems/package/tar_reader/entry.rb', line 31

def header
  @header
end

Class Method Details

.open(header, io, &block) ⇒ Object

Creates a new tar entry for header that will be read from io If a block is given, the entry is yielded and then closed.



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# File 'lib/rubygems/package/tar_reader/entry.rb', line 18

def self.open(header, io, &block)
  entry = new header, io
  return entry unless block_given?
  begin
    yield entry
  ensure
    entry.close
  end
end

Instance Method Details

#bytes_read ⇒ Object

Number of bytes read out of the tar entry



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# File 'lib/rubygems/package/tar_reader/entry.rb', line 52

def bytes_read
  @read
end

#check_closed ⇒ Object

:nodoc:

Raises:

  • (IOError) 


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# File 'lib/rubygems/package/tar_reader/entry.rb', line 45

def check_closed # :nodoc:
  raise IOError, "closed #{self.class}" if closed?
end

#close ⇒ Object

Closes the tar entry



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# File 'lib/rubygems/package/tar_reader/entry.rb', line 59

def close
  return if closed?
  # Seek to the end of the entry if it wasn't fully read
  seek(0, IO::SEEK_END)
  # discard trailing zeros
  skip = (512 - (@header.size % 512)) % 512
  @io.read(skip)
  @closed = true
  nil
end

#closed? ⇒ Boolean

Is the tar entry closed?

Returns:

  • (Boolean) 


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# File 'lib/rubygems/package/tar_reader/entry.rb', line 73

def closed?
  @closed
end

#directory? ⇒ Boolean

Is this tar entry a directory?

Returns:

  • (Boolean) 


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# File 'lib/rubygems/package/tar_reader/entry.rb', line 112

def directory?
  @header.typeflag == "5"
end

#eof? ⇒ Boolean

Are we at the end of the tar entry?

Returns:

  • (Boolean) 


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# File 'lib/rubygems/package/tar_reader/entry.rb', line 80

def eof?
  check_closed

  @read >= @header.size
end

#file? ⇒ Boolean

Is this tar entry a file?

Returns:

  • (Boolean) 


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# File 'lib/rubygems/package/tar_reader/entry.rb', line 119

def file?
  @header.typeflag == "0"
end

#full_name ⇒ Object

Full name of the tar entry



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# File 'lib/rubygems/package/tar_reader/entry.rb', line 89

def full_name
  @header.full_name.force_encoding(Encoding::UTF_8)
rescue ArgumentError => e
  raise unless e.message == "string contains null byte"
  raise Gem::Package::TarInvalidError,
        "tar is corrupt, name contains null byte"
end

#getc ⇒ Object

Read one byte from the tar entry



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

def getc
  return nil if eof?

  ret = @io.getc
  @read += 1 if ret

  ret
end

#pos ⇒ Object

The position in the tar entry



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# File 'lib/rubygems/package/tar_reader/entry.rb', line 133

def pos
  check_closed

  bytes_read
end

#pos=(new_pos) ⇒ Object

Seek to the position in the tar entry



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# File 'lib/rubygems/package/tar_reader/entry.rb', line 142

def pos=(new_pos)
  seek(new_pos, IO::SEEK_SET)
end

#read(maxlen = nil) ⇒ Object

Reads maxlen bytes from the tar file entry, or the rest of the entry if nil



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# File 'lib/rubygems/package/tar_reader/entry.rb', line 155

def read(maxlen = nil)
  if eof?
    return maxlen.to_i.zero? ? "" : nil
  end

  max_read = [maxlen, @header.size - @read].compact.min

  ret = @io.read max_read
  if ret.nil?
    return maxlen ? nil : "" # IO.read returns nil on EOF with len argument
  end
  @read += ret.size

  ret
end

#readpartial(maxlen, outbuf = "".b) ⇒ Object 



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# File 'lib/rubygems/package/tar_reader/entry.rb', line 171

def readpartial(maxlen, outbuf = "".b)
  if eof? && maxlen > 0
    raise EOFError, "end of file reached"
  end

  max_read = [maxlen, @header.size - @read].min

  @io.readpartial(max_read, outbuf)
  @read += outbuf.size

  outbuf
end

#rewind ⇒ Object

Rewinds to the beginning of the tar file entry



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# File 'lib/rubygems/package/tar_reader/entry.rb', line 240

def rewind
  check_closed
  seek(0, IO::SEEK_SET)
end

#seek(offset, whence = IO::SEEK_SET) ⇒ Object

Seeks to offset bytes into the tar file entry whence can be IO::SEEK_SET, IO::SEEK_CUR, or IO::SEEK_END



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# File 'lib/rubygems/package/tar_reader/entry.rb', line 188

def seek(offset, whence = IO::SEEK_SET)
  check_closed

  new_pos =
    case whence
    when IO::SEEK_SET then @orig_pos + offset
    when IO::SEEK_CUR then @io.pos + offset
    when IO::SEEK_END then @end_pos + offset
    else
      raise ArgumentError, "invalid whence"
    end

  if new_pos < @orig_pos
    new_pos = @orig_pos
  elsif new_pos > @end_pos
    new_pos = @end_pos
  end

  pending = new_pos - @io.pos

  return 0 if pending == 0

  if @io.respond_to?(:seek)
    begin
      # avoid reading if the @io supports seeking
      @io.seek new_pos, IO::SEEK_SET
      pending = 0
    rescue Errno::EINVAL
    end
  end

  # if seeking isn't supported or failed
  # negative seek requires that we rewind and read
  if pending < 0
    @io.rewind
    pending = new_pos
  end

  while pending > 0 do
    size_read = @io.read([pending, 4096].min)&.size
    raise(EOFError, "end of file reached") if size_read.nil?
    pending -= size_read
  end

  @read = @io.pos - @orig_pos

  0
end

#size ⇒ Object Also known as: length 



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# File 'lib/rubygems/package/tar_reader/entry.rb', line 146

def size
  @header.size
end

#symlink? ⇒ Boolean

Is this tar entry a symlink?

Returns:

  • (Boolean) 


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# File 'lib/rubygems/package/tar_reader/entry.rb', line 126

def symlink?
  @header.typeflag == "2"
end