探究 ACE 的 Proactor_Test 示例中的 Acceptor 和 Connector 分别如何与 Proactor 关联。

在 ACE 提供的 Proactor_Test 示例中，整篇代码看不出  Acceptor 和 Connector 是如何与创建的 Proactor 实例关联的，深入ACE源码，顺藤摸瓜，发现这些关联是在ACE内部建立起来的。

Proactor_Test 示例代码在 \ACE-6.0.0\ACE_wrappers\tests 目录下。

Proactor_Test.cpp 文件（文件太长，有删减）：

// $Id: Proactor_Test.cpp 91673 2010-09-08 18:49:47Z johnnyw $

// ============================================================================
/**
 *  @file Proactor_Test.cpp
 *
 *  $Id: Proactor_Test.cpp 91673 2010-09-08 18:49:47Z johnnyw $
 *
 *  This program illustrates how the ACE_Proactor can be used to
 *  implement an application that does various asynchronous
 *  operations.
 *
 *  @author Alexander Libman <[email protected]>
 */
// ============================================================================

int
MyTask::create_proactor (ProactorType type_proactor, size_t max_op)
{
  ACE_GUARD_RETURN (ACE_SYNCH_RECURSIVE_MUTEX,
                    monitor,
                    this->lock_,
                    -1);

  ACE_ASSERT (this->proactor_ == 0);

#if defined (ACE_WIN32)

  ACE_UNUSED_ARG (type_proactor);
  ACE_UNUSED_ARG (max_op);

  ACE_WIN32_Proactor *proactor_impl = 0;

  ACE_NEW_RETURN (proactor_impl,
                  ACE_WIN32_Proactor,
                  -1);

  ACE_DEBUG ((LM_DEBUG,
              ACE_TEXT("(%t) Create Proactor Type = WIN32\n")));

#elif defined (ACE_HAS_AIO_CALLS)

  ACE_POSIX_Proactor * proactor_impl = 0;

  switch (type_proactor)
    {
    case AIOCB:
      ACE_NEW_RETURN (proactor_impl,
                      ACE_POSIX_AIOCB_Proactor (max_op),
                      -1);
      ACE_DEBUG ((LM_DEBUG,
                  ACE_TEXT ("(%t) Create Proactor Type = AIOCB\n")));
      break;

#if defined(ACE_HAS_POSIX_REALTIME_SIGNALS)
    case SIG:
      ACE_NEW_RETURN (proactor_impl,
                      ACE_POSIX_SIG_Proactor (max_op),
                      -1);
      ACE_DEBUG ((LM_DEBUG,
                  ACE_TEXT ("(%t) Create Proactor Type = SIG\n")));
      break;
#endif /* ACE_HAS_POSIX_REALTIME_SIGNALS */

#  if defined (sun)
    case SUN:
      ACE_NEW_RETURN (proactor_impl,
                      ACE_SUN_Proactor (max_op),
                      -1);
      ACE_DEBUG ((LM_DEBUG,
                  ACE_TEXT("(%t) Create Proactor Type = SUN\n")));
      break;
#  endif /* sun */

#  if !defined(ACE_HAS_BROKEN_SIGEVENT_STRUCT)
    case CB:
      ACE_NEW_RETURN (proactor_impl,
                      ACE_POSIX_CB_Proactor (max_op),
                      -1);
      ACE_DEBUG ((LM_DEBUG,
                  ACE_TEXT ("(%t) Create Proactor Type = CB\n")));
      break;
#  endif /* !ACE_HAS_BROKEN_SIGEVENT_STRUCT */

    default:
      ACE_DEBUG ((LM_DEBUG,
                  ACE_TEXT ("(%t) Create Proactor Type = DEFAULT\n")));
      break;
  }

#endif /* ACE_WIN32 */

  // always delete implementation  1 , not  !(proactor_impl == 0)
  ACE_NEW_RETURN (this->proactor_,
                  ACE_Proactor (proactor_impl, 1 ),
                  -1);
  // Set new singleton and delete it in close_singleton()
  ACE_Proactor::instance (this->proactor_, 1); 
  return 0;
}

int
MyTask::delete_proactor (void)
{
  ACE_GUARD_RETURN (ACE_SYNCH_RECURSIVE_MUTEX,
                    monitor,
                    this->lock_,
                    -1);

  ACE_DEBUG ((LM_DEBUG,
              ACE_TEXT ("(%t) Delete Proactor\n")));

  ACE_Proactor::close_singleton ();
  this->proactor_ = 0;

  return 0;
}

int
MyTask::start (int num_threads,
               ProactorType type_proactor,
               size_t max_op)
{
  if (this->create_proactor (type_proactor, max_op) == -1)
    ACE_ERROR_RETURN ((LM_ERROR,
                       ACE_TEXT ("%p.\n"),
                       ACE_TEXT ("unable to create proactor")),
                      -1);

  if (this->activate (THR_NEW_LWP, num_threads) == -1)
    ACE_ERROR_RETURN ((LM_ERROR,
                       ACE_TEXT ("%p.\n"),
                       ACE_TEXT ("unable to activate thread pool")),
                      -1);

  for (; num_threads > 0; num_threads--)
    {
      sem_.acquire ();
    }

  return 0;
}


int
MyTask::stop ()
{
  if (this->proactor_ != 0)
    {
      ACE_DEBUG ((LM_DEBUG,
                  ACE_TEXT ("(%t) Calling End Proactor event loop\n")));

      this->proactor_->proactor_end_event_loop ();
    }

  if (this->wait () == -1)
    ACE_ERROR ((LM_ERROR,
                ACE_TEXT ("%p.\n"),
                ACE_TEXT ("unable to stop thread pool")));

  return 0;
}

int
MyTask::svc (void)
{
  ACE_DEBUG ((LM_DEBUG, ACE_TEXT ("(%t) MyTask started\n")));

  disable_signal (ACE_SIGRTMIN, ACE_SIGRTMAX);
  disable_signal (SIGPIPE, SIGPIPE);

  // signal that we are ready
  sem_.release (1);

  ACE_Proactor::run_event_loop ();

  ACE_DEBUG ((LM_DEBUG, ACE_TEXT ("(%t) MyTask finished\n")));
  return 0;
}

class Acceptor : public ACE_Asynch_Acceptor<Server>
{
public:
  Acceptor (TestData *tester);
  virtual ~Acceptor (void);

  // Virtual from ACE_Asynch_Acceptor
  Server *make_handler (void);

private:
  TestData *tester_;
};

// *************************************************************
Acceptor::Acceptor (TestData *tester)
  : tester_ (tester)
{
}

Acceptor::~Acceptor (void)
{
  this->cancel ();
}

Server *
Acceptor::make_handler (void)
{
  return this->tester_->server_up ();
}

// *******************************************
//  Connector
// *******************************************

class Connector : public ACE_Asynch_Connector<Client>
{
public:
  Connector (TestData *tester);
  virtual ~Connector (void);

  int  start (const ACE_INET_Addr &addr, int num);

  // Virtual from ACE_Asynch_Connector
  Client *make_handler (void);

private:
  TestData *tester_;
};

// *************************************************************

Connector::Connector (TestData *tester)
  : tester_ (tester)
{
}

Connector::~Connector (void)
{
  this->cancel ();
}

Client *
Connector::make_handler (void)
{
  return this->tester_->client_up ();
}


int
Connector::start (const ACE_INET_Addr& addr, int num)
{
  if (num > MAX_CLIENTS)
    num = MAX_CLIENTS;

  if (num < 0)
    num = 1;

  int rc = 0;

  // int open  ( int pass_addresses = 0,
  //             ACE_Proactor *proactor = 0,
  //             int validate_new_connection = 0 );

  if (this->open (1, 0, 1) != 0)
  {
     ACE_ERROR ((LM_ERROR,
                 ACE_TEXT ("(%t) %p\n"),
                 ACE_TEXT ("Connector::open failed")));
     return rc;
  }

  for (; rc < num;  rc++)
    {
      if (this->connect (addr) != 0)
        {
          ACE_ERROR ((LM_ERROR,
                      ACE_TEXT ("(%t) %p\n"),
                      ACE_TEXT ("Connector::connect failed")));
          break;
        }
    }
  return rc;
}


int
run_main (int argc, ACE_TCHAR *argv[])
{
  ACE_START_TEST (ACE_TEXT ("Proactor_Test"));

  if (::parse_args (argc, argv) == -1)
    return -1;

  disable_signal (ACE_SIGRTMIN, ACE_SIGRTMAX);
  disable_signal (SIGPIPE, SIGPIPE);

  MyTask    task1;
  TestData  test;

  if (task1.start (threads, proactor_type, max_aio_operations) == 0)
    {
      Acceptor  acceptor (&test);
      Connector connector (&test);
      ACE_INET_Addr addr (port);

      int rc = 0;

      if (both != 0 || host == 0) // Acceptor
        {
          // Simplify, initial read with zero size
          if (acceptor.open (addr, 0, 1) == 0)
            rc = 1;
        }

      if (both != 0 || host != 0)
        {
          if (host == 0)
            host = ACE_LOCALHOST;

          if (addr.set (port, host, 1, addr.get_type ()) == -1)
            ACE_ERROR ((LM_ERROR, ACE_TEXT ("%p\n"), host));
          else
            rc += connector.start (addr, clients);
        }

      // Wait a few seconds to let things get going, then poll til
      // all sessions are done. Note that when we exit this scope, the
      // Acceptor and Connector will be destroyed, which should prevent
      // further connections and also test how well destroyed handlers
      // are handled.
      ACE_OS::sleep (3);
    }
  ACE_DEBUG ((LM_DEBUG, ACE_TEXT ("(%t) Sleeping til sessions run down.\n")));
  while (!test.testing_done ())
    ACE_OS::sleep (1);

  test.stop_all ();

  ACE_DEBUG ((LM_DEBUG, ACE_TEXT ("(%t) Stop Thread Pool Task\n")));
  task1.stop ();

  ACE_END_TEST;

  return 0;
}

#else

int
run_main (int, ACE_TCHAR *[])
{
  ACE_START_TEST (ACE_TEXT ("Proactor_Test"));

  ACE_DEBUG ((LM_INFO,
              ACE_TEXT ("Threads or Asynchronous IO is unsupported.\n")
              ACE_TEXT ("Proactor_Test will not be run.")));

  ACE_END_TEST;

  return 0;
}

#endif  /* ACE_HAS_WIN32_OVERLAPPED_IO || ACE_HAS_AIO_CALLS */

分析如下：

1. ACE_Proactor::instance (this->proactor_, 1);  // 把创建的Proactor实例传入ACE_Proactor类中保存。

2. 
int run_main (int argc, ACE_TCHAR *argv[])
{
  ...

  if (both != 0 || host == 0) // Acceptor
  {
      // Simplify, initial read with zero size
      // 调用Acceptor的open函数，看似与创建的proactor实例没有一点关系，但深入ACE代码内部就知道，Acceptor和Proactor是在内部关联了。
      if (acceptor.open (addr, 0, 1) == 0)
         rc = 1;
   }
   ...
}

 

3.
int Connector::start (const ACE_INET_Addr& addr, int num)
{
   ...

  // 与Acceptor类似，调用Connector的open函数，看似与创建的proactor实例没有一点关系，但深入ACE代码内部就知道，Connector和Proactor是在内部关联了。
  if (this->open (1, 0, 1) != 0) 
  {
     ACE_ERROR ((LM_ERROR,
                 ACE_TEXT ("(%t) %p\n"),
                 ACE_TEXT ("Connector::open failed")));
     return rc;
  }
  ...
}