class TrinoSqlParser::SupportProcess

Public Class Methods

new(idle_wait: 2, with_tokens:) click to toggle source
# File lib/trino_sql_parser/support_process.rb, line 5
def initialize(idle_wait: 2, with_tokens:)
  @idle_wait = idle_wait
  @with_tokens = with_tokens
  @mutex = Mutex.new
  @last_used_pid = nil
  @pipe = nil
  @pid = nil
end

Public Instance Methods

kill!() click to toggle source
# File lib/trino_sql_parser/support_process.rb, line 32
def kill!
  @mutex.synchronize do
    if @pid
      Process.kill("KILL", @pid)
      @pipe.close rescue nil
      @pipe = nil
      @pid = nil
    end
  end
end
receive_line() click to toggle source
# File lib/trino_sql_parser/support_process.rb, line 52
def receive_line
  @pipe.gets
end
send_line(line) click to toggle source
# File lib/trino_sql_parser/support_process.rb, line 43
def send_line(line)
  @mutex.synchronize do  # block kill! during execution
    start! unless @pipe
    @pipe.puts line
    @last_used_pid = @pipe.pid
  end
  nil
end
start!() click to toggle source
# File lib/trino_sql_parser/support_process.rb, line 14
def start!
  return if @pipe

  cmd = (
    [TrinoSqlParser.java_cmd] +
    TrinoSqlParser.java_args.map {|arg| Shellwords.escape(arg) } +
    ["-jar", Shellwords.escape(TrinoSqlParser.jar_path)]
  ).join(' ')

  if @with_tokens
    cmd << " --with-tokens"
  end

  @pipe = IO.popen(TrinoSqlParser.java_env, cmd, "r+", external_encoding: 'UTF-8')
  @pid = @pipe.pid
  Thread.new(@pid, &method(:monitor_thread))
end

Private Instance Methods

monitor_thread(pid) click to toggle source
# File lib/trino_sql_parser/support_process.rb, line 58
def monitor_thread(pid)
  while true
    done = Process.waitpid2(pid, Process::WNOHANG) rescue true
    break if done

    sleep @idle_wait
    if @last_used_pid != pid
      kill! rescue nil
    end

    @last_used_pid = nil  # Next check kills the process
  end
end