processor.hpp

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#pragma once
 
/// @file userver/os_signals/processor.hpp
/// @brief @copybrief os_signals::Processor
 
#include <userver/concurrent/async_event_channel.hpp>
#include <userver/engine/task/task_processor_fwd.hpp>
#include <userver/os_signals/subscriber.hpp>
#include <userver/utils/internal_tag_fwd.hpp>
 
USERVER_NAMESPACE_BEGIN
 
namespace os_signals {
 
#if !defined(__APPLE__)
 
/// @brief Constant for SIGUSR1
inline constexpr int kSigUsr1 = 10;
 
/// @brief Constant for SIGUSR2
inline constexpr int kSigUsr2 = 12;
 
#else
inline constexpr int kSigUsr1 = 30;
inline constexpr int kSigUsr2 = 31;
#endif
 
/// @ingroup userver_clients
///
/// @brief A client that allows to subscribe
/// to OS signals `SIGUSR1 and `SIGUSR2`.
///
/// Usually retrieved from os_signals::ProcessorComponent component. For tests
/// use os_signals::ProcessorMock.
///
/// @see @ref scripts/docs/en/userver/os_signals.md
class Processor final {
 public:
  explicit Processor(engine::TaskProcessor& task_processor);
 
  /// Listen for a specific signal `signum`. See the other overload for
  /// subscription to both signals.
  template <class Class>
  Subscriber AddListener(Class* obj, std::string_view name, int signum,
                         void (Class::*func)()) {
    auto execute = [obj, func, signum](int sig) {
      if (sig == signum) {
        (obj->*func)();
      }
    };
 
    return channel_.AddListener(concurrent::FunctionId(obj), name,
                                std::move(execute));
  }
 
  /// Listen for all the OS signals.
  template <class Class>
  Subscriber AddListener(Class* obj, std::string_view name,
                         void (Class::*func)(int /*signum*/)) {
    auto execute = [obj, func](int sig) { (obj->*func)(sig); };
    return channel_.AddListener(concurrent::FunctionId(obj), name,
                                std::move(execute));
  }
 
  /// @cond
  // For internal use
  void Notify(int signum, utils::InternalTag);
  /// @endcond
 private:
  concurrent::AsyncEventChannel<int> channel_;
  engine::TaskProcessor& task_processor_;
};
 
}  // namespace os_signals
 
USERVER_NAMESPACE_END