Optimized ConditionVariable Windows implementation

Former-commit-id: 4f2e582d64e8f3a1f83cea2bd0f7220987aa4332

src/Nazara/Core/Win32/ConditionVariableImpl.cpp

@@ -14,16 +14,16 @@ NzConditionVariableImpl::NzConditionVariableImpl()
 	InitializeConditionVariable(&m_cv);
 	#else
 	m_count = 0;
-	InitializeCriticalSection(&m_countLock);
-	m_events[SIGNAL] = CreateEvent(nullptr, false, false, nullptr); // auto-reset event
 	m_events[BROADCAST] = CreateEvent(nullptr, true, false, nullptr); // manual-reset event
+	m_events[SIGNAL] = CreateEvent(nullptr, false, false, nullptr); // auto-reset event
 	#endif
 }
 
 #if !NAZARA_CORE_WINDOWS_VISTA
 NzConditionVariableImpl::~NzConditionVariableImpl()
 {
-	DeleteCriticalSection(&m_countLock);
+	CloseHandle(m_events[BROADCAST]);
+	CloseHandle(m_events[SIGNAL]);
 }
 #endif
 
@@ -32,12 +32,7 @@ void NzConditionVariableImpl::Signal()
 	#if NAZARA_CORE_WINDOWS_VISTA
 	WakeConditionVariable(&m_cv);
 	#else
-	// Avoid race conditions.
-	EnterCriticalSection(&m_countLock);
-	bool haveWaiters = (m_count > 0);
-	LeaveCriticalSection(&m_countLock);
-
-	if (haveWaiters)
+	if (m_count > 0)
 		SetEvent(m_events[SIGNAL]);
 	#endif
 }
@@ -47,12 +42,7 @@ void NzConditionVariableImpl::SignalAll()
 	#if NAZARA_CORE_WINDOWS_VISTA
 	WakeAllConditionVariable(&m_cv);
 	#else
-	// Avoid race conditions.
-	EnterCriticalSection(&m_countLock);
-	bool haveWaiters = (m_count > 0);
-	LeaveCriticalSection (&m_countLock);
-
-	if (haveWaiters)
+	if (m_count > 0)
 		SetEvent(m_events[BROADCAST]);
 	#endif
 }
@@ -67,10 +57,7 @@ bool NzConditionVariableImpl::Wait(NzMutexImpl* mutex, nzUInt32 timeout)
 	#if NAZARA_CORE_WINDOWS_VISTA
 	return SleepConditionVariableCS(&m_cv, &mutex->m_criticalSection, timeout);
 	#else
-	// Avoid race conditions.
-	EnterCriticalSection(&m_countLock);
 	m_count++;
-	LeaveCriticalSection(&m_countLock);
 
 	// It's ok to release the mutex here since Win32
 	// manual-reset events maintain state when used with SetEvent.
@@ -80,13 +67,8 @@ bool NzConditionVariableImpl::Wait(NzMutexImpl* mutex, nzUInt32 timeout)
 	// Wait for either event to become signaled due to Signal being called or SignalAll being called.
 	int result = WaitForMultipleObjects(2, m_events, false, timeout);
 
-	EnterCriticalSection(&m_countLock);
-	m_count--;
-	bool lastWaiter = (result == WAIT_OBJECT_0 + BROADCAST && m_count == 0);
-	LeaveCriticalSection(&m_countLock);
-
 	// Some thread called SignalAll
-	if (lastWaiter)
+	if (--m_count == 0 && result == WAIT_OBJECT_0 + BROADCAST)
 		// We're the last waiter to be notified or to stop waiting, so reset the manual event.
 		ResetEvent(m_events[BROADCAST]);
 

src/Nazara/Core/Win32/ConditionVariableImpl.hpp

@@ -10,6 +10,7 @@
 #define NAZARA_CONDITIONVARIABLEIMPL_HPP
 
 #include <Nazara/Prerequesites.hpp>
+#include <atomic>
 #include <windows.h>
 
 class NzMutexImpl;
@@ -41,9 +42,8 @@ class NzConditionVariableImpl
 			MAX_EVENTS
 		};
 
-		CRITICAL_SECTION m_countLock;
+		std::atomic_uint m_count;
 		HANDLE m_events[MAX_EVENTS];
-		unsigned int m_count;
 		#endif
 
 };