Module: NA::Pager

Defined in:
lib/na/pager.rb

Overview

Pagination

Class Attribute Summary collapse

Class Method Summary collapse

Class Attribute Details

.paginate ⇒ Boolean

Boolean determines whether output is paginated

Returns:

  • (Boolean) —

    true if paginated



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# File 'lib/na/pager.rb', line 12

def paginate
  @paginate ||= false
end

Class Method Details

.page(text) ⇒ Boolean?

Page output. If @paginate is false, just dump to STDOUT

Parameters:

  • text (String) —

    text to paginate

Returns:

  • (Boolean, nil) —

    true if paged, false if not, nil if no pager



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# File 'lib/na/pager.rb', line 25

def page(text)
  unless @paginate
    puts text
    return
  end

  # Skip pagination for small outputs (faster than starting a pager)
  if text.length < 2000 && text.lines.count < 50
    puts text
    return
  end

  pager = which_pager
  return false unless pager

  # Optimized pager execution - use spawn instead of fork+exec
  read_io, write_io = IO.pipe

  # Use spawn for better performance than fork+exec
  pid = spawn(pager, in: read_io, out: $stdout, err: $stderr)
  read_io.close

  begin
    # Write data to pager
    write_io.write(text)
    write_io.close

    # Wait for pager to complete
    _, status = Process.waitpid2(pid)
    status.success?
  rescue SystemCallError
    # Clean up on error
    begin
      write_io.close
    rescue StandardError
      nil
    end
    begin
      Process.kill('TERM', pid)
    rescue StandardError
      nil
    end
    begin
      Process.waitpid(pid)
    rescue StandardError
      nil
    end
    false
  end
end