/**

 * WinPR: Windows Portable Runtime

 * Countdown Event

 *

 * Copyright 2012 Marc-Andre Moreau <marcandre.moreau@gmail.com>

 *

 * Licensed under the Apache License, Version 2.0 (the "License");

 * you may not use this file except in compliance with the License.

 * You may obtain a copy of the License at

 *

 *     http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

#include <winpr/config.h>

#include <winpr/assert.h>

#include <winpr/crt.h>

#include <winpr/collections.h>

struct CountdownEvent

{

  size_t count;

  CRITICAL_SECTION lock;

  HANDLE event;

  size_t initialCount;

};

/**

 * C equivalent of the C# CountdownEvent Class

 * http://msdn.microsoft.com/en-us/library/dd235708/

 */

/**

 * Properties

 */

/**

 * Gets the number of remaining signals required to set the event.

 */

size_t CountdownEvent_CurrentCount(wCountdownEvent* countdown)

{

  WINPR_ASSERT(countdown);

  EnterCriticalSection(&countdown->lock);

  const size_t rc = countdown->count;

  LeaveCriticalSection(&countdown->lock);

  return rc;

}

/**

 * Gets the numbers of signals initially required to set the event.

 */

size_t CountdownEvent_InitialCount(wCountdownEvent* countdown)

{

  WINPR_ASSERT(countdown);

  EnterCriticalSection(&countdown->lock);

  const size_t rc = countdown->initialCount;

  LeaveCriticalSection(&countdown->lock);

  return rc;

}

/**

 * Determines whether the event is set.

 */

BOOL CountdownEvent_IsSet(wCountdownEvent* countdown)

{

  BOOL status = FALSE;

  WINPR_ASSERT(countdown);

  if (WaitForSingleObject(countdown->event, 0) == WAIT_OBJECT_0)

    status = TRUE;

  return status;

}

/**

 * Gets a WaitHandle that is used to wait for the event to be set.

 */

HANDLE CountdownEvent_WaitHandle(wCountdownEvent* countdown)

{

  WINPR_ASSERT(countdown);

  return countdown->event;

}

/**

 * Methods

 */

/**

 * Increments the CountdownEvent's current count by a specified value.

 */

void CountdownEvent_AddCount(wCountdownEvent* countdown, size_t signalCount)

{

  WINPR_ASSERT(countdown);

  EnterCriticalSection(&countdown->lock);

  const BOOL signalSet = countdown->count == 0;

  countdown->count += signalCount;

  if (signalSet)

    (void)ResetEvent(countdown->event);

  LeaveCriticalSection(&countdown->lock);

}

/**

 * Registers multiple signals with the CountdownEvent, decrementing the value of CurrentCount by the

 * specified amount.

 */

BOOL CountdownEvent_Signal(wCountdownEvent* countdown, size_t signalCount)

{

  BOOL status = FALSE;

  BOOL newStatus = FALSE;

  BOOL oldStatus = FALSE;

  WINPR_ASSERT(countdown);

  EnterCriticalSection(&countdown->lock);

  if (WaitForSingleObject(countdown->event, 0) == WAIT_OBJECT_0)

    oldStatus = TRUE;

  if (signalCount <= countdown->count)

    countdown->count -= signalCount;

  else

    countdown->count = 0;

  if (countdown->count == 0)

    newStatus = TRUE;

  if (newStatus && (!oldStatus))

  {

    (void)SetEvent(countdown->event);

    status = TRUE;

  }

  LeaveCriticalSection(&countdown->lock);

  return status;

}

/**

 * Resets the InitialCount property to a specified value.

 */

void CountdownEvent_Reset(wCountdownEvent* countdown, size_t count)

{

  WINPR_ASSERT(countdown);

  countdown->initialCount = count;

}

/**

 * Construction, Destruction

 */

wCountdownEvent* CountdownEvent_New(size_t initialCount)

{

  wCountdownEvent* countdown = (wCountdownEvent*)calloc(1, sizeof(wCountdownEvent));

  if (!countdown)

    return NULL;

  countdown->count = initialCount;

  countdown->initialCount = initialCount;

  if (!InitializeCriticalSectionAndSpinCount(&countdown->lock, 4000))

    goto fail;

  countdown->event = CreateEvent(NULL, TRUE, FALSE, NULL);

  if (!countdown->event)

    goto fail;

  if (countdown->count == 0)

  {

    if (!SetEvent(countdown->event))

      goto fail;

  }

  return countdown;

fail:

  WINPR_PRAGMA_DIAG_PUSH

  WINPR_PRAGMA_DIAG_IGNORED_MISMATCHED_DEALLOC

  CountdownEvent_Free(countdown);

  WINPR_PRAGMA_DIAG_POP

  return NULL;

}

void CountdownEvent_Free(wCountdownEvent* countdown)

{

  if (!countdown)

    return;

  DeleteCriticalSection(&countdown->lock);

  (void)CloseHandle(countdown->event);

  free(countdown);

}