import time

class Timing(object):
  def __init__(self, prefix="", on_exit=None, enabled=True): self.prefix, self.on_exit, self.enabled = prefix, on_exit, enabled
  def __enter__(self): self.st = time.perf_counter_ns()
  def __exit__(self, exc_type, exc_val, exc_tb):
    self.et = time.perf_counter_ns() - self.st
    if self.enabled: print(f"{self.prefix}{self.et*1e-6:.2f} ms"+(self.on_exit(self.et) if self.on_exit else ""))

def enable_early_exec():
  import subprocess, multiprocessing
  qin: multiprocessing.Queue = multiprocessing.Queue()
  qout: multiprocessing.Queue = multiprocessing.Queue()
  def _early_exec_process(qin, qout):
    while 1:
      path, inp = qin.get()
      qout.put(subprocess.check_output(path, input=inp))
  p = multiprocessing.Process(target=_early_exec_process, args=(qin, qout))
  p.daemon = True
  p.start()
  def early_exec(x):
    qin.put(x)
    return qout.get()
  return early_exec