use namespace AzJezz\Mutex;
use namespace HH\Asio;

require 'vendor/autoload.hack';

<<__EntryPoint>>
async function main(): Awaitable<void> {
  Facebook\AutoloadMap\initialize();

  $mutex = new Mutex\Memory();
  
  $jobs = vec[
    foo($mutex), // first to acquire the lock
    foo($mutex), // won't be able to acquire the lock
    foo($mutex), // same
  ];

  foreach($jobs as $job) {
    await $job;
  }
}

async function foo(
  Mutex\MutexInterface $mutex
): Awaitable<void> {
  $lock = await $mutex->acquire('foo');
  if ($lock is nonnull) {
    echo "doing things \n";
    await Asio\usleep(10000000);
    echo "finished my job, releasing the lock \n";
    await $mutex->release($lock);
    return;
  }

  echo "someone else have requested the 'foo' lock\n";
}