tree changes

libs/main/thread/pithreadpoolexecutor.cpp

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+/*
+	PIP - Platform Independent Primitives
+
+	Stephan Fomenko
+
+	This program is free software: you can redistribute it and/or modify
+	it under the terms of the GNU Lesser General Public License as published by
+	the Free Software Foundation, either version 3 of the License, or
+	(at your option) any later version.
+
+	This program is distributed in the hope that it will be useful,
+	but WITHOUT ANY WARRANTY; without even the implied warranty of
+	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+	GNU Lesser General Public License for more details.
+
+	You should have received a copy of the GNU Lesser General Public License
+	along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "pithreadpoolexecutor.h"
+
+/*! \class PIThreadPoolExecutor
+ * @brief Thread pools address two different problems: they usually provide improved performance when executing large
+ * numbers of asynchronous tasks, due to reduced per-task invocation overhead, and they provide a means of bounding and
+ * managing the resources, including threads, consumed when executing a collection of tasks.
+ */
+
+
+PIThreadPoolExecutor::PIThreadPoolExecutor(int corePoolSize) : isShutdown_(false) {
+	for (int i = 0; i < corePoolSize; ++i) {
+		PIThread * thread = new PIThread([&, i](){
+			auto runnable = taskQueue.poll(100, std::function<void()>());
+			if (runnable) {
+				runnable();
+			}
+			if (isShutdown_ && taskQueue.size() == 0) threadPool[i]->stop();
+		});
+		threadPool.push_back(thread);
+		thread->start();
+	}
+}
+
+
+bool PIThreadPoolExecutor::awaitTermination(int timeoutMs) {
+	PITimeMeasurer measurer;
+	for (size_t i = 0; i < threadPool.size(); ++i) {
+		int dif = timeoutMs - (int)measurer.elapsed_m();
+		if (dif < 0) return false;
+		if (!threadPool[i]->waitForFinish(dif)) return false;
+	}
+	return true;
+}
+
+
+void PIThreadPoolExecutor::shutdownNow() {
+	isShutdown_ = true;
+	for (size_t i = 0; i < threadPool.size(); ++i) threadPool[i]->stop();
+}
+
+
+PIThreadPoolExecutor::~PIThreadPoolExecutor() {
+	shutdownNow();
+	while (threadPool.size() > 0) delete threadPool.take_back();
+}
+
+
+void PIThreadPoolExecutor::execute(const std::function<void()> & runnable) {
+	if (!isShutdown_) taskQueue.offer(runnable);
+}
+
+
+bool PIThreadPoolExecutor::isShutdown() const {
+	return isShutdown_;
+}
+
+
+void PIThreadPoolExecutor::shutdown() {
+	isShutdown_ = true;
+}