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proc
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self
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root
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opt
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alt
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ruby33
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share
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rubygems
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rubygems
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package
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tar_reader
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Filename :
entry.rb
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# frozen_string_literal: true # rubocop:disable Style/AsciiComments # Copyright (C) 2004 Mauricio Julio Fernández Pradier # See LICENSE.txt for additional licensing information. # rubocop:enable Style/AsciiComments ## # Class for reading entries out of a tar file class Gem::Package::TarReader::Entry ## # 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. def self.open(header, io, &block) entry = new header, io return entry unless block_given? begin yield entry ensure entry.close end end ## # Header for this tar entry attr_reader :header ## # Creates a new tar entry for +header+ that will be read from +io+ def initialize(header, io) @closed = false @header = header @io = io @orig_pos = @io.pos @end_pos = @orig_pos + @header.size @read = 0 end def check_closed # :nodoc: raise IOError, "closed #{self.class}" if closed? end ## # Number of bytes read out of the tar entry def bytes_read @read end ## # Closes the tar entry 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 ## # Is the tar entry closed? def closed? @closed end ## # Are we at the end of the tar entry? def eof? check_closed @read >= @header.size end ## # Full name of the tar entry def full_name if @header.prefix != "" File.join @header.prefix, @header.name else @header.name end rescue ArgumentError => e raise unless e.message == "string contains null byte" raise Gem::Package::TarInvalidError, "tar is corrupt, name contains null byte" end ## # Read one byte from the tar entry def getc return nil if eof? ret = @io.getc @read += 1 if ret ret end ## # Is this tar entry a directory? def directory? @header.typeflag == "5" end ## # Is this tar entry a file? def file? @header.typeflag == "0" end ## # Is this tar entry a symlink? def symlink? @header.typeflag == "2" end ## # The position in the tar entry def pos check_closed bytes_read end ## # Seek to the position in the tar entry def pos=(new_pos) seek(new_pos, IO::SEEK_SET) end def size @header.size end alias_method :length, :size ## # Reads +maxlen+ bytes from the tar file entry, or the rest of the entry if nil 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 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 ## # Seeks to +offset+ bytes into the tar file entry # +whence+ can be IO::SEEK_SET, IO::SEEK_CUR, or IO::SEEK_END 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 ## # Rewinds to the beginning of the tar file entry def rewind check_closed seek(0, IO::SEEK_SET) end end