timers: Add timer::set_interval()

Author: Tectu

examples/timers/CMakeLists.txt

@@ -1,2 +1,3 @@
 add_subdirectory(basic)
+add_subdirectory(modify_interval)
 add_subdirectory(threadpool)

examples/timers/modify_interval/CMakeLists.txt

@@ -0,0 +1,15 @@
+set(TARGET threadpool-example-timers-modify_interval)
+
+add_executable(${TARGET})
+
+target_link_libraries(
+    ${TARGET}
+    PRIVATE
+        threadpool
+)
+
+target_sources(
+    ${TARGET}
+    PRIVATE
+        main.cpp
+)

examples/timers/modify_interval/main.cpp

@@ -0,0 +1,51 @@
+#include <timer.hpp>
+
+#include <chrono>
+#include <iostream>
+
+void
+print_time(std::ostream& out)
+{
+    using clock_type = std::chrono::steady_clock;
+
+    static const auto start = clock_type::now();
+
+    out << std::chrono::duration_cast<std::chrono::milliseconds>(clock_type::now() - start).count();
+}
+
+int
+main()
+{
+    using namespace std::chrono_literals;
+
+    jbo::timers::executors::standalone<1> te(jbo::timers::manager::instance(), 10ms);
+    te.start();
+
+    // Create periodic timer
+    auto t1 = jbo::timers::manager::instance().periodic(1s, []{
+        static std::size_t i = 0;
+        print_time(std::cout);
+        std::cout << " | periodic 1: (" << i++ << ") --- thread: " << std::this_thread::get_id() << std::endl;
+    });
+
+    std::this_thread::sleep_for(5s);
+
+    // Modify interval
+    std::cout << "Modifying interval" << std::endl;
+    t1.set_interval(250ms);
+
+    std::this_thread::sleep_for(5s);
+
+    // Modify interval
+    std::cout << "Modifying interval" << std::endl;
+    t1.set_interval(2500ms);
+
+    std::this_thread::sleep_for(5s);
+
+    std::cout << "stopping timer executor..." << std::endl;
+    te.stop();
+
+    std::cout << "done" << std::endl;
+
+    return EXIT_SUCCESS;
+}

lib/jbo/threadpool/timer.hpp

@@ -62,6 +62,17 @@ namespace jbo::timers
         void
         stop();
 
+        /**
+         * Change the interval of a periodic timer.
+         *
+         * @note This will fail (do nothing and return false) if the timer is not a constant interval type.
+         *
+         * @return Whether the interval was changed successfully.
+         */
+        template<typename Rep, typename Period>
+        bool
+        set_interval(const std::chrono::duration<Rep, Period>& interval);
+
     private:
         data* m_data = nullptr;
     };
@@ -71,6 +82,12 @@ namespace jbo::timers
      */
     struct data
     {
+    private:
+        struct periodic_constant;
+        struct periodic_uniform;
+        struct singleshot;
+
+    public:
         /**
          * The task type.
          *
@@ -94,6 +111,20 @@ namespace jbo::timers
             m_enabled = false;
         }
 
+        template<typename Rep, typename Period>
+        bool
+        set_interval(const std::chrono::duration<Rep, Period>& interval)
+        {
+            std::scoped_lock lock(m_mutex);
+
+            if (auto pc = std::get_if<periodic_constant>(&m_data); pc) {
+                pc->interval = std::chrono::duration_cast<decltype(pc->interval)>(interval);
+                return true;
+            }
+
+            return false;
+        }
+
     private:
         friend struct manager;
 
@@ -194,6 +225,17 @@ namespace jbo::timers
             m_data->stop();
     }
 
+    template<typename Rep, typename Period>
+    inline
+    bool
+    timer::set_interval(const std::chrono::duration<Rep, Period>& interval)
+    {
+        if (!m_data) [[unlikely]]
+            return false;
+
+        return m_data->set_interval(interval);
+    }
+
     /**
      * A manager to manage timers.
      *