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 * notice, this list of conditions and the following disclaimer.
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 * in the documentation and/or other materials provided with the
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 * this software without specific prior written permission.
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#ifndef GRPCXX_DYNAMIC_THREAD_POOL_H
#define GRPCXX_DYNAMIC_THREAD_POOL_H

#include <grpc++/config.h>

#include <grpc++/impl/sync.h>
#include <grpc++/impl/thd.h>
#include <grpc++/thread_pool_interface.h>

#include <list>
#include <memory>
#include <queue>

namespace grpc {

class DynamicThreadPool GRPC_FINAL : public ThreadPoolInterface {
 public:
  explicit DynamicThreadPool(int reserve_threads);
  ~DynamicThreadPool();

  void Add(const std::function<void()>& callback) GRPC_OVERRIDE;

 private:
  class DynamicThread {
  public:
    DynamicThread(DynamicThreadPool *pool);
    ~DynamicThread();
  private:
    DynamicThreadPool *pool_;
    std::unique_ptr<grpc::thread> thd_;
    void ThreadFunc();
  };
  grpc::mutex mu_;
  grpc::condition_variable cv_;
  grpc::condition_variable shutdown_cv_;
  bool shutdown_;
  std::queue<std::function<void()>> callbacks_;
  int reserve_threads_;
  int nthreads_;
  int threads_waiting_;
  std::list<DynamicThread*> dead_threads_;

  void ThreadFunc();
  static void ReapThreads(std::list<DynamicThread*>* tlist);
};

}  // namespace grpc

#endif  // GRPCXX_DYNAMIC_THREAD_POOL_H