handlers.h

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// Copyright (c) Space-ng, inc. All rights reserved.
 
#pragma once
 
 
#include "sol3/log/except.h"
 
#include <boost/asio/bind_executor.hpp>
#include <boost/asio/dispatch.hpp>
#include <boost/asio/post.hpp>
 
#include <functional>
#include <memory>
#include <tuple>
#include <utility>
 
namespace sol3::asio {
namespace detail {
 
template <typename TDerived, typename TClass, typename TCallable>
auto bind_weak(std::weak_ptr<TClass> weak_ptr, TCallable&& callable) {
  SOL3_EXPECT(
      weak_ptr.use_count() > 0,
      "weakBind requires an initialized weak_ptr. "
      "(Did you call weak_from_this() in a constructor?)");
 
  return [weak = std::move(weak_ptr),
          cb = std::forward<TCallable>(callable)](auto&&... args) mutable {
    if (auto base_self = weak.lock()) {
      auto self = std::static_pointer_cast<TDerived>(std::move(base_self));
      std::invoke(cb, std::move(self), std::forward<decltype(args)>(args)...);
    }
  };
}
 
template <typename TDerived, typename TClass, typename TCallable>
auto bind_shared(std::shared_ptr<TClass> shared_ptr, TCallable&& callable) {
  SOL3_EXPECT(
      shared_ptr.use_count() > 0,
      "bind requires an initialized shared_ptr. "
      "(Did you call shared_from_this() in a constructor?)");
 
  return [self = std::static_pointer_cast<TDerived>(std::move(shared_ptr)),
          cb = std::forward<TCallable>(callable)](auto&&... args) mutable {
    std::invoke(cb, self, std::forward<decltype(args)>(args)...);
  };
}
 
template <typename TMemberFn, typename... TArgs>
auto pack_method(TMemberFn method, TArgs&&... args) {
  return [method, args_tuple = std::make_tuple(std::forward<TArgs>(args)...)](
             auto self, auto&&... asio_args) mutable {
    std::apply(
        [&](auto&&... unpacked_args) {
          (self.get()->*method)(
              std::forward<decltype(unpacked_args)>(unpacked_args)...,
              std::forward<decltype(asio_args)>(asio_args)...);
        },
        std::move(args_tuple));
  };
}
 
}  // namespace detail
 
// =====================================================================
// WEAK_PTR API
// =====================================================================
 
template <typename TClass, typename TCallable>
auto weakHandler(TClass* obj, TCallable&& callable) {
  if constexpr (std::is_member_function_pointer_v<std::decay_t<TCallable>>) {
    return detail::bind_weak<TClass>(
        obj->weak_from_this(), detail::pack_method(callable));
  } else {
    return detail::bind_weak<TClass>(
        obj->weak_from_this(), std::forward<TCallable>(callable));
  }
}
 
template <typename TExecutor, typename TClass, typename TFunc>
void weakDispatch(TExecutor const& ex, TClass* obj, TFunc&& func) {
  boost::asio::dispatch(
      ex,
      detail::bind_weak<TClass>(
          obj->weak_from_this(), std::forward<TFunc>(func)));
}
 
template <
    typename TExecutor,
    typename TClass,
    typename TMemberFn,
    typename... TArgs>
void weakDispatch(
    TExecutor const& ex, TClass* obj, TMemberFn method, TArgs&&... args) {
  boost::asio::dispatch(
      ex,
      detail::bind_weak<TClass>(
          obj->weak_from_this(),
          detail::pack_method(method, std::forward<TArgs>(args)...)));
}
 
template <typename TExecutor, typename TClass, typename TFunc>
void weakPost(TExecutor const& ex, TClass* obj, TFunc&& func) {
  boost::asio::post(
      ex,
      detail::bind_weak<TClass>(
          obj->weak_from_this(), std::forward<TFunc>(func)));
}
 
template <
    typename TExecutor,
    typename TClass,
    typename TMemberFn,
    typename... TArgs>
void weakPost(
    TExecutor const& ex, TClass* obj, TMemberFn method, TArgs&&... args) {
  boost::asio::post(
      ex,
      detail::bind_weak<TClass>(
          obj->weak_from_this(),
          detail::pack_method(method, std::forward<TArgs>(args)...)));
}
 
template <typename TExecutor, typename TClass, typename TFunc>
decltype(auto) weakBindExecutor(
    TExecutor const& ex, TClass* obj, TFunc&& func) {
  return boost::asio::bind_executor(
      ex,
      detail::bind_weak<TClass>(
          obj->weak_from_this(), std::forward<TFunc>(func)));
}
 
template <
    typename TExecutor,
    typename TClass,
    typename TMemberFn,
    typename... TArgs>
decltype(auto) weakBindExecutor(
    TExecutor const& ex, TClass* obj, TMemberFn method, TArgs&&... args) {
  return boost::asio::bind_executor(
      ex,
      detail::bind_weak<TClass>(
          obj->weak_from_this(),
          detail::pack_method(method, std::forward<TArgs>(args)...)));
}
 
// =====================================================================
// SHARED_PTR API
// =====================================================================
 
template <typename TClass, typename TCallable>
auto handler(TClass* obj, TCallable&& callable) {
  if constexpr (std::is_member_function_pointer_v<std::decay_t<TCallable>>) {
    return detail::bind_shared<TClass>(
        obj->shared_from_this(), detail::pack_method(callable));
  } else {
    return detail::bind_shared<TClass>(
        obj->shared_from_this(), std::forward<TCallable>(callable));
  }
}
 
template <typename TExecutor, typename TClass, typename TFunc>
void dispatch(TExecutor const& ex, TClass* obj, TFunc&& func) {
  boost::asio::dispatch(
      ex,
      detail::bind_shared<TClass>(
          obj->shared_from_this(), std::forward<TFunc>(func)));
}
 
template <
    typename TExecutor,
    typename TClass,
    typename TMemberFn,
    typename... TArgs>
void dispatch(
    TExecutor const& ex, TClass* obj, TMemberFn method, TArgs&&... args) {
  boost::asio::dispatch(
      ex,
      detail::bind_shared<TClass>(
          obj->shared_from_this(),
          detail::pack_method(method, std::forward<TArgs>(args)...)));
}
 
template <typename TExecutor, typename TClass, typename TFunc>
void post(TExecutor const& ex, TClass* obj, TFunc&& func) {
  boost::asio::post(
      ex,
      detail::bind_shared<TClass>(
          obj->shared_from_this(), std::forward<TFunc>(func)));
}
 
template <
    typename TExecutor,
    typename TClass,
    typename TMemberFn,
    typename... TArgs>
void post(TExecutor const& ex, TClass* obj, TMemberFn method, TArgs&&... args) {
  boost::asio::post(
      ex,
      detail::bind_shared<TClass>(
          obj->shared_from_this(),
          detail::pack_method(method, std::forward<TArgs>(args)...)));
}
 
template <typename TExecutor, typename TClass, typename TFunc>
decltype(auto) bindExecutor(TExecutor const& ex, TClass* obj, TFunc&& func) {
  return boost::asio::bind_executor(
      ex,
      detail::bind_shared<TClass>(
          obj->shared_from_this(), std::forward<TFunc>(func)));
}
 
template <
    typename TExecutor,
    typename TClass,
    typename TMemberFn,
    typename... TArgs>
decltype(auto) bindExecutor(
    TExecutor const& ex, TClass* obj, TMemberFn method, TArgs&&... args) {
  return boost::asio::bind_executor(
      ex,
      detail::bind_shared<TClass>(
          obj->shared_from_this(),
          detail::pack_method(method, std::forward<TArgs>(args)...)));
}
 
}  // namespace sol3::asio