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include/utils/throttle.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_THROTTLE_HPP_
+#define INCLUDE_UTILS_THROTTLE_HPP_
+
+#include "common.hpp"
+
+namespace repertory {
+class throttle final {
+public:
+  throttle() : max_size_(10u) {}
+
+  explicit throttle(const std::size_t &max_size) : max_size_(max_size) {}
+
+public:
+  throttle(const throttle &) noexcept = delete;
+  throttle(throttle &&) noexcept = delete;
+  throttle &operator=(const throttle &) = delete;
+  throttle &operator=(throttle &&) = delete;
+
+public:
+  ~throttle() { shutdown(); }
+
+private:
+  const std::size_t max_size_;
+  std::size_t count_ = 0u;
+  bool shutdown_ = false;
+  std::mutex mutex_;
+  std::condition_variable notify_;
+
+public:
+  void decrement();
+
+  void increment_or_wait();
+
+  void reset();
+
+  void shutdown();
+};
+} // namespace repertory
+
+#endif // INCLUDE_UTILS_THROTTLE_HPP_