Module: PtySupport

Included in:
VTParser
Defined in:
lib/vtparser/pty_support.rb

Overview

This module can only be included in class which has a parse method to receive the next character read.

Instance Method Summary collapse

Instance Method Details

#spawn(command, &block) ⇒ Object

Spawn the given command using PTY::spawn, connect pipes and calls parse for each character read.

Caution: While this command is running, STDIN will be in raw mode.

If a block is given, it will be called for each character read, and the character will be replaced by the block’s return value. If nil is returned by block, the character will be dropped.



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# File 'lib/vtparser/pty_support.rb', line 14

def spawn(command, &block)

  begin
    PTY.spawn(command) do |stdout_and_stderr, stdin, pid|

      # Input Thread
      input_thread = Thread.new do

        STDIN.raw do |io|
          loop do
            break if pid.nil?
            begin
              if io.wait_readable(0.1)
                data = io.read_nonblock(1024)
                stdin.write data
              end
            rescue IO::WaitReadable
              # No input available right now
            rescue EOFError
              break
            rescue Errno::EIO
              break
            end
          end
        end
      end

      # Pipe stdout and stderr to the parser
      begin

        begin
          winsize = $stdout.winsize
        rescue Errno::ENOTTY
          winsize = [0, 120] # Default to 120 columns
        end
        # Ensure the child process has the proper window size, because 
        #  - tools such as yarn use it to identify tty mode
        #  - some tools use it to determine the width of the terminal for formatting
        stdout_and_stderr.winsize = winsize
        
        stdout_and_stderr.each_char do |char|

          char = block.call(char) if block_given?
          next if char.nil?
          
          # puts Action.inspect_char(char) + "\r\n"  
          # Pass to parser
          parse(char)

        end
      rescue Errno::EIO
        # End of output
      end

      # Wait for the child process to exit
      Process.wait(pid)
      pid = nil
      input_thread.join
      return exit_status = $?.exitstatus

  end

  rescue PTY::ChildExited => e
    puts "The child process exited: #{e}"
  end
end