first commit

ext/crow/dumb_timer_queue.h

@@ -0,0 +1,81 @@
+#pragma once
+
+#include <boost/asio.hpp>
+#include <deque>
+#include <functional>
+#include <chrono>
+#include <thread>
+
+#include "logging.h"
+
+namespace crow
+{
+    namespace detail 
+    {
+        // fast timer queue for fixed tick value.
+        class dumb_timer_queue
+        {
+        public:
+            using key = std::pair<dumb_timer_queue*, int>;
+
+            void cancel(key& k)
+            {
+                auto self = k.first;
+                k.first = nullptr;
+                if (!self)
+                    return;
+
+                unsigned int index = (unsigned int)(k.second - self->step_);
+                if (index < self->dq_.size())
+                    self->dq_[index].second = nullptr;
+            }
+
+            key add(std::function<void()> f)
+            {
+                dq_.emplace_back(std::chrono::steady_clock::now(), std::move(f));
+                int ret = step_+dq_.size()-1;
+
+                CROW_LOG_DEBUG << "timer add inside: " << this << ' ' << ret ;
+                return {this, ret};
+            }
+
+            void process()
+            {
+                if (!io_service_)
+                    return;
+
+                auto now = std::chrono::steady_clock::now();
+                while(!dq_.empty())
+                {
+                    auto& x = dq_.front();
+                    if (now - x.first < std::chrono::seconds(tick))
+                        break;
+                    if (x.second)
+                    {
+                        CROW_LOG_DEBUG << "timer call: " << this << ' ' << step_;
+                        // we know that timer handlers are very simple currenty; call here
+                        x.second();
+                    }
+                    dq_.pop_front();
+                    step_++;
+                }
+            }
+
+            void set_io_service(boost::asio::io_service& io_service)
+            {
+                io_service_ = &io_service;
+            }
+
+            dumb_timer_queue() noexcept
+            {
+            }
+
+        private:
+
+            int tick{5};
+            boost::asio::io_service* io_service_{};
+            std::deque<std::pair<decltype(std::chrono::steady_clock::now()), std::function<void()>>> dq_;
+            int step_{};
+        };
+    }
+}