granicus.if.org Git - icinga2/blob - lib/base/threadpool.hpp

   1 /* Icinga 2 | (c) 2012 Icinga GmbH | GPLv2+ */
   2
   3 #ifndef THREADPOOL_H
   4 #define THREADPOOL_H
   5
   6 #include "base/exception.hpp"
   7 #include "base/logger.hpp"
   8 #include <cstddef>
   9 #include <exception>
  10 #include <functional>
  11 #include <memory>
  12 #include <thread>
  13 #include <boost/asio/post.hpp>
  14 #include <boost/asio/thread_pool.hpp>
  15 #include <boost/thread/locks.hpp>
  16 #include <boost/thread/shared_mutex.hpp>
  17
  18 namespace icinga
  19 {
  20
  21 enum SchedulerPolicy
  22 {
  23         DefaultScheduler,
  24         LowLatencyScheduler
  25 };
  26
  27 /**
  28  * A thread pool.
  29  *
  30  * @ingroup base
  31  */
  32 class ThreadPool
  33 {
  34 public:
  35         typedef std::function<void ()> WorkFunction;
  36
  37         ThreadPool(size_t threads = std::thread::hardware_concurrency() * 2u);
  38         ~ThreadPool();
  39
  40         void Start();
  41         void Stop();
  42
  43         /**
  44          * Appends a work item to the work queue. Work items will be processed in FIFO order.
  45          *
  46          * @param callback The callback function for the work item.
  47          * @returns true if the item was queued, false otherwise.
  48          */
  49         template<class T>
  50         bool Post(T callback, SchedulerPolicy)
  51         {
  52                 boost::shared_lock<decltype(m_Mutex)> lock (m_Mutex);
  53
  54                 if (m_Pool) {
  55                         boost::asio::post(*m_Pool, [callback]() {
  56                                 try {
  57                                         callback();
  58                                 } catch (const std::exception& ex) {
  59                                         Log(LogCritical, "ThreadPool")
  60                                                 << "Exception thrown in event handler:\n"
  61                                                 << DiagnosticInformation(ex);
  62                                 } catch (...) {
  63                                         Log(LogCritical, "ThreadPool", "Exception of unknown type thrown in event handler.");
  64                                 }
  65                         });
  66
  67                         return true;
  68                 } else {
  69                         return false;
  70                 }
  71         }
  72
  73 private:
  74         boost::shared_mutex m_Mutex;
  75         std::unique_ptr<boost::asio::thread_pool> m_Pool;
  76         size_t m_Threads;
  77 };
  78
  79 }
  80
  81 #endif /* THREADPOOL_H */