Added Task Scheduler

Former-commit-id: ac37f749ae78f364db3d3edfabc8221802579989

src/Nazara/Core/TaskScheduler.cpp

@@ -0,0 +1,150 @@
+// Copyright (C) 2012 Jérôme Leclercq
+// This file is part of the "Nazara Engine - Core module"
+// For conditions of distribution and use, see copyright notice in Config.hpp
+
+
+
+#include <Nazara/Core/TaskScheduler.hpp>
+#include <Nazara/Core/ConditionVariable.hpp>
+#include <Nazara/Core/Error.hpp>
+#include <Nazara/Core/LockGuard.hpp>
+#include <Nazara/Core/Mutex.hpp>
+#include <Nazara/Core/Thread.hpp>
+#include <queue>
+#include <vector>
+#include <Nazara/Core/Debug.hpp>
+
+namespace
+{
+	struct TaskSchedulerImpl
+	{
+		std::queue<NzFunctor*> tasks;
+		std::vector<NzThread*> workers;
+		NzConditionVariable waiterConditionVariable;
+		NzConditionVariable workerConditionVariable;
+		NzMutex taskMutex;
+		NzMutex waiterConditionVariableMutex;
+		NzMutex workerConditionVariableMutex;
+		volatile bool running = true;
+	};
+
+	TaskSchedulerImpl* s_impl = nullptr;
+
+	void WorkerFunc()
+	{
+		do
+		{
+			NzFunctor* task;
+			{
+				NzLockGuard lock(s_impl->taskMutex);
+				if (!s_impl->tasks.empty())
+				{
+					task = s_impl->tasks.front();
+					s_impl->tasks.pop();
+				}
+				else
+					task = nullptr;
+			}
+
+			// Avons-nous une tâche ?
+			if (task)
+				task->Run(); // Chouette ! Allons travailler gaiement
+			else
+			{
+				// On peut signaler à tout le monde qu'il n'y a plus de tâches
+				s_impl->waiterConditionVariableMutex.Lock();
+				s_impl->waiterConditionVariable.SignalAll();
+				s_impl->waiterConditionVariableMutex.Unlock();
+
+				// Dans le cas contraire, nous attendons qu'une nouvelle tâche arrive
+				s_impl->workerConditionVariableMutex.Lock();
+				s_impl->workerConditionVariable.Wait(&s_impl->workerConditionVariableMutex);
+				s_impl->workerConditionVariableMutex.Unlock();
+			}
+		}
+		while (s_impl->running);
+	}
+}
+
+bool NzTaskScheduler::Initialize()
+{
+	if (s_impl)
+		return true; // Déjà initialisé
+
+	s_impl = new TaskSchedulerImpl;
+
+	unsigned int workerCount = NzThread::HardwareConcurrency();
+	for (unsigned int i = 0; i < workerCount; ++i)
+	{
+		NzThread* thread = new NzThread(WorkerFunc);
+		s_impl->workers.push_back(thread);
+	}
+
+	return true;
+}
+
+void NzTaskScheduler::Uninitialize()
+{
+	if (s_impl)
+	{
+		s_impl->running = false;
+
+		s_impl->workerConditionVariableMutex.Lock();
+		s_impl->workerConditionVariable.SignalAll();
+		s_impl->workerConditionVariableMutex.Unlock();
+
+		for (NzThread* thread : s_impl->workers)
+		{
+			thread->Join();
+			delete thread;
+		}
+
+		delete s_impl;
+	}
+}
+
+void NzTaskScheduler::AddTaskFunctor(NzFunctor* taskFunctor)
+{
+	#ifdef NAZARA_CORE_SAFE
+	if (!s_impl)
+	{
+		NazaraError("Task scheduler is not initialized");
+		return;
+	}
+	#endif
+
+	{
+		NzLockGuard lock(s_impl->taskMutex);
+		s_impl->tasks.push(taskFunctor);
+	}
+
+	s_impl->workerConditionVariableMutex.Lock();
+	s_impl->workerConditionVariable.Signal();
+	s_impl->workerConditionVariableMutex.Unlock();
+}
+
+void NzTaskScheduler::WaitForTasks()
+{
+	#ifdef NAZARA_CORE_SAFE
+	if (!s_impl)
+	{
+		NazaraError("Task scheduler is not initialized");
+		return;
+	}
+	#endif
+
+	s_impl->taskMutex.Lock();
+	// Tout d'abord, il y a-t-il des tâches en attente ?
+	if (s_impl->tasks.empty())
+	{
+		s_impl->taskMutex.Unlock();
+		return;
+	}
+
+	// On verrouille d'abord la mutex entourant le signal (Pour ne pas perdre le signal en chemin)
+	s_impl->waiterConditionVariableMutex.Lock();
+	// Et ensuite seulement on déverrouille la mutex des tâches
+	s_impl->taskMutex.Unlock();
+	s_impl->waiterConditionVariable.Wait(&s_impl->waiterConditionVariableMutex);
+	s_impl->waiterConditionVariableMutex.Unlock();
+}