feat: added async ticker

Signed-off-by: Yash Pandey (YP) <[email protected]>

Author: EmperorYP7

casbin/casbin.vcxproj

@@ -158,6 +158,7 @@
     <ClCompile Include="effect\default_effector.cpp" />
     <ClCompile Include="enforcer.cpp" />
     <ClCompile Include="enforcer_cached.cpp" />
+    <ClCompile Include="util\ticker.cpp" />
     <ClCompile Include="exception\casbin_adapter_exception.cpp" />
     <ClCompile Include="exception\casbin_enforcer_exception.cpp" />
     <ClCompile Include="exception\casbin_rbac_exception.cpp" />
@@ -288,6 +289,7 @@
     <ClInclude Include="util\built_in_functions.h" />
     <ClInclude Include="util\pch.h" />
     <ClInclude Include="util\util.h" />
+    <ClInclude Include="util\ticker.h" />
   </ItemGroup>
   <ItemGroup>
     <None Include=".clang-format" />

casbin/casbin.vcxproj.filters

@@ -171,6 +171,9 @@
     <ClCompile Include="util\array_equals.cpp">
       <Filter>Source Files\util</Filter>
     </ClCompile>
+    <ClCompile Include="util\ticker.cpp">
+      <Filter>Source Files\util</Filter>
+    </ClCompile>
     <ClCompile Include="util\array_remove_duplicates.cpp">
       <Filter>Source Files\util</Filter>
     </ClCompile>
@@ -473,6 +476,9 @@
     <ClInclude Include="enforcer_synced.h">
        <Filter>Header Files</Filter>
     </ClInclude>
+    <ClInclude Include="util\ticker.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
   </ItemGroup>
   <ItemGroup>
     <None Include=".clang-format" />

casbin/util/ticker.cpp

@@ -0,0 +1,54 @@
+/*
+* Copyright 2020 The casbin Authors. All Rights Reserved.
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+*    http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+#include "pch.h"
+
+#ifndef TICKER_CPP
+#define TICKER_CPP
+
+#include "./ticker.h"
+
+Ticker::Ticker(function<void()> onTick, chrono::duration<int64_t, nano> tickInterval)
+    : _onTick (onTick)
+    , _tickInterval (tickInterval)
+    , _running (false) {}
+
+Ticker::~Ticker () {
+    stop();
+}
+
+void Ticker::start() {
+    if (_running) return;
+    _running = true;
+    _futures1.push_back(async(launch::async, &Ticker::timer_loop, this));
+}
+
+void Ticker::stop() { 
+    _running = false; 
+}
+
+void Ticker::timer_loop()
+{
+    while (_running) {
+        {
+            lock_guard<mutex> lock(_tickIntervalMutex);
+            _futures2.push_back(async(launch::async, _onTick));
+            this_thread::sleep_for( _tickInterval );
+        }
+    }
+}
+
+#endif // TICKER_CPP

casbin/util/ticker.h

@@ -0,0 +1,56 @@
+/*
+ * Copyright 2020 The casbin Authors. All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef TICKER_H
+#define TICKER_H
+
+#include <cstdint>
+#include <functional>
+#include <chrono>
+#include <vector>
+#include <thread>
+#include <future>
+#include <condition_variable>
+#include <iostream>
+#include <mutex>
+
+using namespace std;
+
+class Ticker {
+public:
+    typedef chrono::duration<int64_t, nano> tick_interval_t;
+    typedef function<void()> on_tick_t;
+    typedef vector<future<void>> future_vec;
+
+    Ticker(function<void()> onTick, chrono::duration<int64_t, nano> tickInterval);
+    
+    ~Ticker();
+
+    void start();
+
+    void stop();
+
+private:
+    void timer_loop();
+    on_tick_t           _onTick;
+    tick_interval_t     _tickInterval;
+    atomic_bool    _running;
+    mutex          _tickIntervalMutex;
+    future_vec          _futures1;
+    future_vec          _futures2;
+};
+
+#endif // TICKER_H