Add SimpleTimer class: A simple timer for timeout and interval applications, using one dedicated service_runner thread per instance.

1 files changed, 147 insertions, 0 deletions

diff --git a/include/jau/simple_timer.hpp b/include/jau/simple_timer.hpp
new file mode 100644
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+++ b/include/jau/simple_timer.hpp
@@ -0,0 +1,147 @@
+/*
+ * Author: Sven Gothel <[email protected]>
+ * Copyright (c) 2022 Gothel Software e.K.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sublicense, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be
+ * included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#ifndef JAU_SIMPLE_TIMER_HPP_
+#define JAU_SIMPLE_TIMER_HPP_
+
+#include <cstdint>
+#include <mutex>
+#include <condition_variable>
+#include <thread>
+
+#include <jau/ordered_atomic.hpp>
+#include <jau/function_def.hpp>
+#include <jau/service_runner.hpp>
+
+namespace jau {
+
+    /**
+     * A simple timer for timeout and interval applications,
+     * using one dedicated service_runner thread per instance.
+     *
+     * Discussion: It is contemplated to add an implementation using a unique singleton service_runner
+     * for multiple timer instances via event loops.
+     */
+    class SimpleTimer {
+        public:
+            typedef SimpleTimer& Timer0_ref;
+
+            /**
+             * User defined timer function using millisecond granularity.
+             *
+             * Function gets invoked for each timer event,
+             * i.e. after reaching the duration in milliseconds set earlier.
+             *
+             * @return duration in milliseconds for the next timer event or zero to end the timer thread.
+             */
+            typedef FunctionDef<nsize_t, Timer0_ref> Timer_func_ms;
+
+        private:
+            service_runner timer_service;
+            std::mutex mtx_timerfunc;
+            Timer_func_ms timer_func_ms;
+            jau::relaxed_atomic_nsize_t duration_ms;
+
+            void timer_worker(service_runner& sr_ref) {
+                do {
+                    std::this_thread::sleep_for(std::chrono::milliseconds(duration_ms));
+                    Timer_func_ms tf;
+                    {
+                        std::unique_lock<std::mutex> lockReader(mtx_timerfunc); // RAII-style acquire and relinquish via destructor
+                        tf = timer_func_ms;
+                    }
+                    if( FunctionType::Null != tf.getType() && !sr_ref.get_shall_stop() ) {
+                        duration_ms = tf.invoke(*this);
+                    } else {
+                        duration_ms = 0;
+                    }
+                } while ( 0 < duration_ms );
+            }
+
+        public:
+            SimpleTimer(const std::string& name, const nsize_t service_shutdown_timeout_ms) noexcept
+            : timer_service(name, service_shutdown_timeout_ms, jau::bindMemberFunc(this, &SimpleTimer::timer_worker)),
+              timer_func_ms(), duration_ms(0)
+            {}
+
+            /**
+             * No copy constructor nor move constructor.
+             * @param o
+             */
+            SimpleTimer(const SimpleTimer& o) = delete;
+
+            /**
+             * Returns true if timer is running
+             */
+            bool is_running() const { return timer_service.is_running(); }
+
+            /**
+             * Start the timer with given user Timer_func_ms function and initial duration in milliseconds.
+             *
+             * @param duration_ms_ initial timer duration until next timer event in milliseconds
+             * @param tofunc user Timer_func_ms to be called on next timer event
+             * @return true if timer has been started, otherwise false implies timer is already running.
+             */
+            bool start(nsize_t duration_ms_, Timer_func_ms tofunc) {
+                if( timer_service.is_running() ) {
+                    return false;
+                }
+                timer_func_ms = tofunc;
+                duration_ms = duration_ms_;
+                timer_service.start();
+                return true;
+            }
+
+            /**
+             * Start or update the timer with given user Timer_func_ms function and initial duration in milliseconds.
+             *
+             * This is faster than calling stop() and start(), however,
+             * an already started timer user Timer_func_ms will proceed.
+             *
+             * @param duration_ms_ initial timer duration until next timer event in milliseconds
+             * @param tofunc user Timer_func_ms to be called on next timer event
+             */
+            void start_or_update(nsize_t duration_ms_, Timer_func_ms tofunc) {
+                if( timer_service.is_running() ) {
+                    std::unique_lock<std::mutex> lockReader(mtx_timerfunc); // RAII-style acquire and relinquish via destructor
+                    timer_func_ms = tofunc;
+                    duration_ms = duration_ms_;
+                } else {
+                    timer_func_ms = tofunc;
+                    duration_ms = duration_ms_;
+                    timer_service.start();
+                }
+            }
+
+            /**
+             * Stop timer
+             */
+            void stop() {
+                timer_service.stop();
+            }
+    };
+
+} /* namespace jau */
+
+#endif /* JAU_SIMPLE_TIMER_HPP_ */