class ActiveStorage::Previewer

def capture(*argv, to:)
  to.binmode
  open_tempfile do |err|
    IO.popen(argv, err: err) { |out| IO.copy_stream(out, to) }
    err.rewind
    unless $?.success?
      raise PreviewError, "#{argv.first} failed (status #{$?.exitstatus}): #{err.read.to_s.chomp}"
    end
  end
  to.rewind
end