/*-------------------------------------------------------------------------
 * drawElements Thread Library
 * ---------------------------
 *
 * Copyright 2014 The Android Open Source Project
 *
 * 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.
 *
 *//*!
 * \file
 * \brief Win32 implementation of mutex.
 *//*--------------------------------------------------------------------*/

#include "deMutex.h"

#if (DE_OS == DE_OS_WIN32 || DE_OS == DE_OS_WINCE)

#include "deMemory.h"

#define VC_EXTRALEAN
#define WIN32_LEAN_AND_MEAN
#define NOMINMAX
#include <windows.h>

/* Critical section objects are more lightweight than mutexes on Win32. */
#define USE_CRITICAL_SECTION 1

#if defined(USE_CRITICAL_SECTION)

enum
{
	CRITICAL_SECTION_SPIN_COUNT	= 2048
};

DE_STATIC_ASSERT(sizeof(deMutex) >= sizeof(CRITICAL_SECTION*));

deMutex deMutex_create (const deMutexAttributes* attributes)
{
	CRITICAL_SECTION* criticalSection = (CRITICAL_SECTION*)deMalloc(sizeof(CRITICAL_SECTION));
	if (!criticalSection)
		return 0;

	DE_UNREF(attributes);
	/* \note [2012-11-05 pyry] Critical sections are always recursive. */

	if (!InitializeCriticalSectionAndSpinCount(criticalSection, CRITICAL_SECTION_SPIN_COUNT))
	{
		deFree(criticalSection);
		return 0;
	}

	return (deMutex)criticalSection;
}

void deMutex_destroy (deMutex mutex)
{
	DeleteCriticalSection((CRITICAL_SECTION*)mutex);
	deFree((CRITICAL_SECTION*)mutex);
}

void deMutex_lock (deMutex mutex)
{
	EnterCriticalSection((CRITICAL_SECTION*)mutex);
}

void deMutex_unlock (deMutex mutex)
{
	LeaveCriticalSection((CRITICAL_SECTION*)mutex);
}

deBool deMutex_tryLock (deMutex mutex)
{
	return TryEnterCriticalSection((CRITICAL_SECTION*)mutex) == TRUE;
}

#else

DE_STATIC_ASSERT(sizeof(deMutex) >= sizeof(HANDLE));

deMutex deMutex_create (const deMutexAttributes* attributes)
{
	HANDLE handle = DE_NULL;
	
	DE_UNREF(attributes);
	/* \note [2009-11-12 pyry] Created mutex is always recursive. */
	
	handle = CreateMutex(DE_NULL, FALSE, DE_NULL);
	return (deMutex)handle;
}

void deMutex_destroy (deMutex mutex)
{
	HANDLE handle = (HANDLE)mutex;
	CloseHandle(handle);
}

void deMutex_lock (deMutex mutex)
{
	HANDLE	handle	= (HANDLE)mutex;
	DWORD	ret		= WaitForSingleObject(handle, INFINITE);
	DE_ASSERT(ret == WAIT_OBJECT_0);
}

void deMutex_unlock (deMutex mutex)
{
	HANDLE	handle	= (HANDLE)mutex;
	BOOL	ret		= ReleaseMutex(handle);
	DE_ASSERT(ret == TRUE);
}

deBool deMutex_tryLock (deMutex mutex)
{
	HANDLE	handle	= (HANDLE)mutex;
	DWORD	ret		= WaitForSingleObject(handle, 0);
	return (ret == WAIT_OBJECT_0);
}

#endif /* USE_CRITICAL_SECTION */

#endif /* DE_OS */