From 0915b3ef56dfac3113cce55a59a5765dc94976be Mon Sep 17 00:00:00 2001
From: Daniel Baumann <daniel.baumann@progress-linux.org>
Date: Sun, 28 Apr 2024 14:34:54 +0200
Subject: Adding upstream version 2.13.6.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
---
 lib/base/threadpool.hpp | 98 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 98 insertions(+)
 create mode 100644 lib/base/threadpool.hpp

(limited to 'lib/base/threadpool.hpp')

diff --git a/lib/base/threadpool.hpp b/lib/base/threadpool.hpp
new file mode 100644
index 0000000..af351cd
--- /dev/null
+++ b/lib/base/threadpool.hpp
@@ -0,0 +1,98 @@
+/* Icinga 2 | (c) 2012 Icinga GmbH | GPLv2+ */
+
+#ifndef THREADPOOL_H
+#define THREADPOOL_H
+
+#include "base/atomic.hpp"
+#include "base/exception.hpp"
+#include "base/logger.hpp"
+#include <cstddef>
+#include <exception>
+#include <functional>
+#include <memory>
+#include <thread>
+#include <boost/asio/post.hpp>
+#include <boost/asio/thread_pool.hpp>
+#include <boost/thread/locks.hpp>
+#include <boost/thread/shared_mutex.hpp>
+#include <cstdint>
+
+namespace icinga
+{
+
+enum SchedulerPolicy
+{
+	DefaultScheduler,
+	LowLatencyScheduler
+};
+
+/**
+ * A thread pool.
+ *
+ * @ingroup base
+ */
+class ThreadPool
+{
+public:
+	typedef std::function<void ()> WorkFunction;
+
+	ThreadPool(size_t threads = std::thread::hardware_concurrency() * 2u);
+	~ThreadPool();
+
+	void Start();
+	void Stop();
+
+	/**
+	 * Appends a work item to the work queue. Work items will be processed in FIFO order.
+	 *
+	 * @param callback The callback function for the work item.
+	 * @returns true if the item was queued, false otherwise.
+	 */
+	template<class T>
+	bool Post(T callback, SchedulerPolicy)
+	{
+		boost::shared_lock<decltype(m_Mutex)> lock (m_Mutex);
+
+		if (m_Pool) {
+			m_Pending.fetch_add(1);
+
+			boost::asio::post(*m_Pool, [this, callback]() {
+				m_Pending.fetch_sub(1);
+
+				try {
+					callback();
+				} catch (const std::exception& ex) {
+					Log(LogCritical, "ThreadPool")
+						<< "Exception thrown in event handler:\n"
+						<< DiagnosticInformation(ex);
+				} catch (...) {
+					Log(LogCritical, "ThreadPool", "Exception of unknown type thrown in event handler.");
+				}
+			});
+
+			return true;
+		} else {
+			return false;
+		}
+	}
+
+	/**
+	 * Returns the amount of queued tasks not started yet.
+	 *
+	 * @returns amount of queued tasks.
+	 */
+	inline uint_fast64_t GetPending()
+	{
+		return m_Pending.load();
+	}
+
+private:
+	boost::shared_mutex m_Mutex;
+	std::unique_ptr<boost::asio::thread_pool> m_Pool;
+	size_t m_Threads;
+	Atomic<uint_fast64_t> m_Pending;
+};
+
+}
+
+#endif /* THREADPOOL_H */
-- 
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