Method: File.rollbackup

Defined in:
lib/rwd/ftools.rb

.rollbackup(file, mode = nil) ⇒ Object 



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# File 'lib/rwd/ftools.rb', line 92

def self.rollbackup(file, mode=nil)
  backupfile	= file + ".RB.BACKUP"
  controlfile	= file + ".RB.CONTROL"
  res		= nil

  File.touch(file)    unless File.file?(file)

	# Rollback

  if File.file?(backupfile) and File.file?(controlfile)
    $stderr.puts "Restoring #{file}..."

    File.copy(backupfile, file)				# Rollback from phase 3
  end

	# Reset

  File.delete(backupfile)	if File.file?(backupfile)	# Reset from phase 2 or 3
  File.delete(controlfile)	if File.file?(controlfile)	# Reset from phase 3 or 4

	# Backup

  File.copy(file, backupfile)					# Enter phase 2
  File.touch(controlfile)					# Enter phase 3

	# The real thing

  if block_given?
    if mode.nil?
      res	= yield
    else
      File.open(file, mode) do |f|
        res	= yield(f)
      end
    end
  end

	# Cleanup

  File.delete(backupfile)					# Enter phase 4
  File.delete(controlfile)					# Enter phase 5

	# Return, like File.open

  res	= File.open(file, (mode or "r"))	unless block_given?

  res
end