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include/utils/polling.hpp

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+/*
+  Copyright <2018-2022> <scott.e.graves@protonmail.com>
+
+  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 INCLUDE_UTILS_POLLING_HPP_
+#define INCLUDE_UTILS_POLLING_HPP_
+
+#include "common.hpp"
+
+namespace repertory {
+class app_config;
+class polling final {
+public:
+  struct polling_item {
+    std::string name;
+    bool low_frequency;
+    std::function<void()> action;
+  };
+
+public:
+  polling(const polling &) = delete;
+  polling(polling &&) = delete;
+  polling &operator=(const polling &) = delete;
+  polling &operator=(polling &&) = delete;
+
+private:
+  polling() = default;
+
+  ~polling() { stop(); }
+
+private:
+  static polling instance_;
+
+public:
+  static polling &instance() { return instance_; }
+
+private:
+  app_config *config_ = nullptr;
+  std::unique_ptr<std::thread> high_frequency_thread_;
+  std::unordered_map<std::string, polling_item> items_;
+  std::unique_ptr<std::thread> low_frequency_thread_;
+  std::mutex mutex_;
+  std::condition_variable notify_;
+  std::mutex start_stop_mutex_;
+  bool stop_requested_ = false;
+
+private:
+  void frequency_thread(std::function<std::uint32_t()> get_frequency_seconds, bool low_frequency);
+
+public:
+  void remove_callback(const std::string &name);
+
+  void set_callback(const polling_item &item);
+
+  void start(app_config *config);
+
+  void stop();
+};
+} // namespace repertory
+
+#endif // INCLUDE_UTILS_POLLING_HPP_