Initial Commit

include/asio/impl/system_executor.hpp

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+//
+// impl/system_executor.hpp
+// ~~~~~~~~~~~~~~~~~~~~~~~~
+//
+// Copyright (c) 2003-2025 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+//
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef ASIO_IMPL_SYSTEM_EXECUTOR_HPP
+#define ASIO_IMPL_SYSTEM_EXECUTOR_HPP
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1200)
+# pragma once
+#endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
+
+#include "asio/detail/executor_op.hpp"
+#include "asio/detail/global.hpp"
+#include "asio/detail/type_traits.hpp"
+#include "asio/system_context.hpp"
+
+#include "asio/detail/push_options.hpp"
+
+namespace asio {
+
+template <typename Blocking, typename Relationship, typename Allocator>
+inline system_context&
+basic_system_executor<Blocking, Relationship, Allocator>::query(
+    execution::context_t) noexcept
+{
+  return detail::global<system_context>();
+}
+
+template <typename Blocking, typename Relationship, typename Allocator>
+inline std::size_t
+basic_system_executor<Blocking, Relationship, Allocator>::query(
+    execution::occupancy_t) const noexcept
+{
+  return detail::global<system_context>().num_threads_;
+}
+
+template <typename Blocking, typename Relationship, typename Allocator>
+template <typename Function>
+inline void
+basic_system_executor<Blocking, Relationship, Allocator>::do_execute(
+    Function&& f, execution::blocking_t::possibly_t) const
+{
+  // Obtain a non-const instance of the function.
+  detail::non_const_lvalue<Function> f2(f);
+
+#if !defined(ASIO_NO_EXCEPTIONS)
+  try
+  {
+#endif// !defined(ASIO_NO_EXCEPTIONS)
+    detail::fenced_block b(detail::fenced_block::full);
+    static_cast<decay_t<Function>&&>(f2.value)();
+#if !defined(ASIO_NO_EXCEPTIONS)
+  }
+  catch (...)
+  {
+    std::terminate();
+  }
+#endif// !defined(ASIO_NO_EXCEPTIONS)
+}
+
+template <typename Blocking, typename Relationship, typename Allocator>
+template <typename Function>
+inline void
+basic_system_executor<Blocking, Relationship, Allocator>::do_execute(
+    Function&& f, execution::blocking_t::always_t) const
+{
+  // Obtain a non-const instance of the function.
+  detail::non_const_lvalue<Function> f2(f);
+
+#if !defined(ASIO_NO_EXCEPTIONS)
+  try
+  {
+#endif// !defined(ASIO_NO_EXCEPTIONS)
+    detail::fenced_block b(detail::fenced_block::full);
+    static_cast<decay_t<Function>&&>(f2.value)();
+#if !defined(ASIO_NO_EXCEPTIONS)
+  }
+  catch (...)
+  {
+    std::terminate();
+  }
+#endif// !defined(ASIO_NO_EXCEPTIONS)
+}
+
+template <typename Blocking, typename Relationship, typename Allocator>
+template <typename Function>
+void basic_system_executor<Blocking, Relationship, Allocator>::do_execute(
+    Function&& f, execution::blocking_t::never_t) const
+{
+  system_context& ctx = detail::global<system_context>();
+
+  // Allocate and construct an operation to wrap the function.
+  typedef detail::executor_op<decay_t<Function>, Allocator> op;
+  typename op::ptr p = { detail::addressof(allocator_),
+      op::ptr::allocate(allocator_), 0 };
+  p.p = new (p.v) op(static_cast<Function&&>(f), allocator_);
+
+  if (is_same<Relationship, execution::relationship_t::continuation_t>::value)
+  {
+    ASIO_HANDLER_CREATION((ctx, *p.p,
+          "system_executor", &ctx, 0, "execute(blk=never,rel=cont)"));
+  }
+  else
+  {
+    ASIO_HANDLER_CREATION((ctx, *p.p,
+          "system_executor", &ctx, 0, "execute(blk=never,rel=fork)"));
+  }
+
+  ctx.scheduler_.post_immediate_completion(p.p,
+      is_same<Relationship, execution::relationship_t::continuation_t>::value);
+  p.v = p.p = 0;
+}
+
+#if !defined(ASIO_NO_TS_EXECUTORS)
+template <typename Blocking, typename Relationship, typename Allocator>
+inline system_context& basic_system_executor<
+    Blocking, Relationship, Allocator>::context() const noexcept
+{
+  return detail::global<system_context>();
+}
+
+template <typename Blocking, typename Relationship, typename Allocator>
+template <typename Function, typename OtherAllocator>
+void basic_system_executor<Blocking, Relationship, Allocator>::dispatch(
+    Function&& f, const OtherAllocator&) const
+{
+  decay_t<Function>(static_cast<Function&&>(f))();
+}
+
+template <typename Blocking, typename Relationship, typename Allocator>
+template <typename Function, typename OtherAllocator>
+void basic_system_executor<Blocking, Relationship, Allocator>::post(
+    Function&& f, const OtherAllocator& a) const
+{
+  system_context& ctx = detail::global<system_context>();
+
+  // Allocate and construct an operation to wrap the function.
+  typedef detail::executor_op<decay_t<Function>, OtherAllocator> op;
+  typename op::ptr p = { detail::addressof(a), op::ptr::allocate(a), 0 };
+  p.p = new (p.v) op(static_cast<Function&&>(f), a);
+
+  ASIO_HANDLER_CREATION((ctx, *p.p,
+        "system_executor", &this->context(), 0, "post"));
+
+  ctx.scheduler_.post_immediate_completion(p.p, false);
+  p.v = p.p = 0;
+}
+
+template <typename Blocking, typename Relationship, typename Allocator>
+template <typename Function, typename OtherAllocator>
+void basic_system_executor<Blocking, Relationship, Allocator>::defer(
+    Function&& f, const OtherAllocator& a) const
+{
+  system_context& ctx = detail::global<system_context>();
+
+  // Allocate and construct an operation to wrap the function.
+  typedef detail::executor_op<decay_t<Function>, OtherAllocator> op;
+  typename op::ptr p = { detail::addressof(a), op::ptr::allocate(a), 0 };
+  p.p = new (p.v) op(static_cast<Function&&>(f), a);
+
+  ASIO_HANDLER_CREATION((ctx, *p.p,
+        "system_executor", &this->context(), 0, "defer"));
+
+  ctx.scheduler_.post_immediate_completion(p.p, true);
+  p.v = p.p = 0;
+}
+#endif // !defined(ASIO_NO_TS_EXECUTORS)
+
+} // namespace asio
+
+#include "asio/detail/pop_options.hpp"
+
+#endif // ASIO_IMPL_SYSTEM_EXECUTOR_HPP