conditionVarFullWin32Impl.I

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/**
 * PANDA 3D SOFTWARE
 * Copyright (c) Carnegie Mellon University.  All rights reserved.
 *
 * All use of this software is subject to the terms of the revised BSD
 * license.  You should have received a copy of this license along
 * with this source code in a file named "LICENSE."
 *
 * @file conditionVarFullWin32Impl.I
 * @author drose
 * @date 2006-08-28
 */

/**
 *
 */
INLINE ConditionVarFullWin32Impl::
ConditionVarFullWin32Impl(MutexWin32Impl &mutex) {
  _external_mutex = &mutex._lock;

  // Create an auto-reset event and a manual-reset event.
  _event_signal = CreateEvent(nullptr, false, false, nullptr);
  _event_broadcast = CreateEvent(nullptr, true, false, nullptr);

  _waiters_count = 0;
}

/**
 *
 */
INLINE ConditionVarFullWin32Impl::
~ConditionVarFullWin32Impl() {
  CloseHandle(_event_signal);
  CloseHandle(_event_broadcast);
}

/**
 *
 */
INLINE void ConditionVarFullWin32Impl::
wait() {
  AtomicAdjust::inc(_waiters_count);

  // It's ok to release the external_mutex here since Win32 manual-reset
  // events maintain state when used with SetEvent(). This avoids the "lost
  // wakeup" bug...
  LeaveCriticalSection(_external_mutex);

  // Wait for either event to become signaled due to notify() being called or
  // notify_all() being called.
  int result = WaitForMultipleObjects(2, &_event_signal, FALSE, INFINITE);

  bool nonzero = AtomicAdjust::dec(_waiters_count);
  bool last_waiter = (result == WAIT_OBJECT_0 + 1 && !nonzero);

  // Some thread called notify_all().
  if (last_waiter) {
    // We're the last waiter to be notified or to stop waiting, so reset the
    // manual event.
    ResetEvent(_event_broadcast);
  }

  // Reacquire the <external_mutex>.
  EnterCriticalSection(_external_mutex);
}

/**
 *
 */
INLINE void ConditionVarFullWin32Impl::
wait(double timeout) {
  AtomicAdjust::inc(_waiters_count);

  // It's ok to release the external_mutex here since Win32 manual-reset
  // events maintain state when used with SetEvent(). This avoids the "lost
  // wakeup" bug...
  LeaveCriticalSection(_external_mutex);

  // Wait for either event to become signaled due to notify() being called or
  // notify_all() being called.
  int result = WaitForMultipleObjects(2, &_event_signal, FALSE, (DWORD)(timeout * 1000.0));

  bool nonzero = AtomicAdjust::dec(_waiters_count);
  bool last_waiter = (result == WAIT_OBJECT_0 + 1 && !nonzero);

  // Some thread called notify_all().
  if (last_waiter) {
    // We're the last waiter to be notified or to stop waiting, so reset the
    // manual event.
    ResetEvent(_event_broadcast);
  }

  // Reacquire the <external_mutex>.
  EnterCriticalSection(_external_mutex);
}

/**
 *
 */
INLINE void ConditionVarFullWin32Impl::
notify() {
  bool have_waiters = AtomicAdjust::get(_waiters_count) > 0;

  if (have_waiters) {
    SetEvent(_event_signal);
  }
}

/**
 *
 */
INLINE void ConditionVarFullWin32Impl::
notify_all() {
  bool have_waiters = AtomicAdjust::get(_waiters_count) > 0;

  if (have_waiters) {
    SetEvent(_event_broadcast);
  }
}