grpc/include/grpc++/impl/sync_no_cxx11.h

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 *
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#ifndef GRPCXX_IMPL_SYNC_NO_CXX11_H
#define GRPCXX_IMPL_SYNC_NO_CXX11_H

#include <grpc/support/sync.h>

namespace grpc {

template<class mutex>
class lock_guard;
class condition_variable;

class mutex {
 public:
  mutex() { gpr_mu_init(&mu_); }
  ~mutex() { gpr_mu_destroy(&mu_); }
 private:
  ::gpr_mu mu_;
  template <class mutex>
  friend class lock_guard;
  friend class condition_variable;
};

template <class mutex>
class lock_guard {
 public:
  lock_guard(mutex &mu) : mu_(mu), locked(true) { gpr_mu_lock(&mu.mu_); }
  ~lock_guard() { unlock_internal(); }
 protected:
  void lock_internal() {
    if (!locked) gpr_mu_lock(&mu_.mu_);
    locked = true;
  }
  void unlock_internal() {
    if (locked) gpr_mu_unlock(&mu_.mu_);
    locked = false;
  }
 private:
  mutex &mu_;
  bool locked;
  friend class condition_variable;
};

template <class mutex>
class unique_lock : public lock_guard<mutex> {
 public:
  unique_lock(mutex &mu) : lock_guard(mu) { }
  void lock() { lock_internal(); }
  void unlock() { unlock_internal(); }
};

class condition_variable {
 public:
  condition_variable() { gpr_cv_init(&cv_); }
  ~condition_variable() { gpr_cv_destroy(&cv_); }
  void wait(lock_guard<mutex> &mu) {
    mu.locked = false;
    gpr_cv_wait(&cv_, &mu.mu_.mu_, gpr_inf_future);
    mu.locked = true;
  }
  void notify_one() { gpr_cv_signal(&cv_); }
  void notify_all() { gpr_cv_broadcast(&cv_); }
 private:
  gpr_cv cv_;
};

}  // namespace grpc

#endif  // GRPCXX_IMPL_SYNC_NO_CXX11_H