update boost

linx64/include/boost/asio/executor_work_guard.hpp

@@ -1,8 +1,8 @@
 //
 // executor_work_guard.hpp
-// ~~~~~~~~~~~~~~~~~
+// ~~~~~~~~~~~~~~~~~~~~~~~
 //
-// Copyright (c) 2003-2019 Christopher M. Kohlhoff (chris at kohlhoff dot com)
+// Copyright (c) 2003-2023 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)
@@ -16,8 +16,10 @@
 #endif // defined(_MSC_VER) && (_MSC_VER >= 1200)
 
 #include <boost/asio/detail/config.hpp>
+
 #include <boost/asio/associated_executor.hpp>
 #include <boost/asio/detail/type_traits.hpp>
+#include <boost/asio/execution.hpp>
 #include <boost/asio/is_executor.hpp>
 
 #include <boost/asio/detail/push_options.hpp>
@@ -25,8 +27,18 @@
 namespace boost {
 namespace asio {
 
-/// An object of type @c executor_work_guard controls ownership of executor work
-/// within a scope.
+#if !defined(BOOST_ASIO_EXECUTOR_WORK_GUARD_DECL)
+#define BOOST_ASIO_EXECUTOR_WORK_GUARD_DECL
+
+template <typename Executor, typename = void, typename = void>
+class executor_work_guard;
+
+#endif // !defined(BOOST_ASIO_EXECUTOR_WORK_GUARD_DECL)
+
+#if defined(GENERATING_DOCUMENTATION)
+
+/// An object of type @c executor_work_guard controls ownership of outstanding
+/// executor work within a scope.
 template <typename Executor>
 class executor_work_guard
 {
@@ -38,6 +50,50 @@ public:
   /**
    * Stores a copy of @c e and calls <tt>on_work_started()</tt> on it.
    */
+  explicit executor_work_guard(const executor_type& e) BOOST_ASIO_NOEXCEPT;
+
+  /// Copy constructor.
+  executor_work_guard(const executor_work_guard& other) BOOST_ASIO_NOEXCEPT;
+
+  /// Move constructor.
+  executor_work_guard(executor_work_guard&& other) BOOST_ASIO_NOEXCEPT;
+
+  /// Destructor.
+  /**
+   * Unless the object has already been reset, or is in a moved-from state,
+   * calls <tt>on_work_finished()</tt> on the stored executor.
+   */
+  ~executor_work_guard();
+
+  /// Obtain the associated executor.
+  executor_type get_executor() const BOOST_ASIO_NOEXCEPT;
+
+  /// Whether the executor_work_guard object owns some outstanding work.
+  bool owns_work() const BOOST_ASIO_NOEXCEPT;
+
+  /// Indicate that the work is no longer outstanding.
+  /**
+   * Unless the object has already been reset, or is in a moved-from state,
+   * calls <tt>on_work_finished()</tt> on the stored executor.
+   */
+  void reset() BOOST_ASIO_NOEXCEPT;
+};
+
+#endif // defined(GENERATING_DOCUMENTATION)
+
+#if !defined(GENERATING_DOCUMENTATION)
+
+#if !defined(BOOST_ASIO_NO_TS_EXECUTORS)
+
+template <typename Executor>
+class executor_work_guard<Executor,
+    typename enable_if<
+      is_executor<Executor>::value
+    >::type>
+{
+public:
+  typedef Executor executor_type;
+
   explicit executor_work_guard(const executor_type& e) BOOST_ASIO_NOEXCEPT
     : executor_(e),
       owns_(true)
@@ -45,7 +101,6 @@ public:
     executor_.on_work_started();
   }
 
-  /// Copy constructor.
   executor_work_guard(const executor_work_guard& other) BOOST_ASIO_NOEXCEPT
     : executor_(other.executor_),
       owns_(other.owns_)
@@ -54,44 +109,31 @@ public:
       executor_.on_work_started();
   }
 
-#if defined(BOOST_ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
-  /// Move constructor.
+#if defined(BOOST_ASIO_HAS_MOVE)
   executor_work_guard(executor_work_guard&& other) BOOST_ASIO_NOEXCEPT
     : executor_(BOOST_ASIO_MOVE_CAST(Executor)(other.executor_)),
       owns_(other.owns_)
   {
     other.owns_ = false;
   }
-#endif //  defined(BOOST_ASIO_HAS_MOVE) || defined(GENERATING_DOCUMENTATION)
+#endif // defined(BOOST_ASIO_HAS_MOVE)
 
-  /// Destructor.
-  /**
-   * Unless the object has already been reset, or is in a moved-from state,
-   * calls <tt>on_work_finished()</tt> on the stored executor.
-   */
   ~executor_work_guard()
   {
     if (owns_)
       executor_.on_work_finished();
   }
 
-  /// Obtain the associated executor.
   executor_type get_executor() const BOOST_ASIO_NOEXCEPT
   {
     return executor_;
   }
 
-  /// Whether the executor_work_guard object owns some outstanding work.
   bool owns_work() const BOOST_ASIO_NOEXCEPT
   {
     return owns_;
   }
 
-  /// Indicate that the work is no longer outstanding.
-  /*
-   * Unless the object has already been reset, or is in a moved-from state,
-   * calls <tt>on_work_finished()</tt> on the stored executor.
-   */
   void reset() BOOST_ASIO_NOEXCEPT
   {
     if (owns_)
@@ -109,54 +151,209 @@ private:
   bool owns_;
 };
 
-/// Create an @ref executor_work_guard object.
+#endif // !defined(BOOST_ASIO_NO_TS_EXECUTORS)
+
 template <typename Executor>
-inline executor_work_guard<Executor> make_work_guard(const Executor& ex,
-    typename enable_if<is_executor<Executor>::value>::type* = 0)
+class executor_work_guard<Executor,
+    typename enable_if<
+      !is_executor<Executor>::value
+    >::type,
+    typename enable_if<
+      execution::is_executor<Executor>::value
+    >::type>
+{
+public:
+  typedef Executor executor_type;
+
+  explicit executor_work_guard(const executor_type& e) BOOST_ASIO_NOEXCEPT
+    : executor_(e),
+      owns_(true)
+  {
+    new (&work_) work_type(boost::asio::prefer(executor_,
+          execution::outstanding_work.tracked));
+  }
+
+  executor_work_guard(const executor_work_guard& other) BOOST_ASIO_NOEXCEPT
+    : executor_(other.executor_),
+      owns_(other.owns_)
+  {
+    if (owns_)
+    {
+      new (&work_) work_type(boost::asio::prefer(executor_,
+            execution::outstanding_work.tracked));
+    }
+  }
+
+#if defined(BOOST_ASIO_HAS_MOVE)
+  executor_work_guard(executor_work_guard&& other) BOOST_ASIO_NOEXCEPT
+    : executor_(BOOST_ASIO_MOVE_CAST(Executor)(other.executor_)),
+      owns_(other.owns_)
+  {
+    if (owns_)
+    {
+      new (&work_) work_type(
+          BOOST_ASIO_MOVE_CAST(work_type)(
+            *static_cast<work_type*>(
+              static_cast<void*>(&other.work_))));
+      other.owns_ = false;
+    }
+  }
+#endif //  defined(BOOST_ASIO_HAS_MOVE)
+
+  ~executor_work_guard()
+  {
+    if (owns_)
+      static_cast<work_type*>(static_cast<void*>(&work_))->~work_type();
+  }
+
+  executor_type get_executor() const BOOST_ASIO_NOEXCEPT
+  {
+    return executor_;
+  }
+
+  bool owns_work() const BOOST_ASIO_NOEXCEPT
+  {
+    return owns_;
+  }
+
+  void reset() BOOST_ASIO_NOEXCEPT
+  {
+    if (owns_)
+    {
+      static_cast<work_type*>(static_cast<void*>(&work_))->~work_type();
+      owns_ = false;
+    }
+  }
+
+private:
+  // Disallow assignment.
+  executor_work_guard& operator=(const executor_work_guard&);
+
+  typedef typename decay<
+      typename prefer_result<
+        const executor_type&,
+        execution::outstanding_work_t::tracked_t
+      >::type
+    >::type work_type;
+
+  executor_type executor_;
+  typename aligned_storage<sizeof(work_type),
+      alignment_of<work_type>::value>::type work_;
+  bool owns_;
+};
+
+#endif // !defined(GENERATING_DOCUMENTATION)
+
+/// Create an @ref executor_work_guard object.
+/**
+ * @param ex An executor.
+ *
+ * @returns A work guard constructed with the specified executor.
+ */
+template <typename Executor>
+BOOST_ASIO_NODISCARD inline executor_work_guard<Executor>
+make_work_guard(const Executor& ex,
+    typename constraint<
+      is_executor<Executor>::value || execution::is_executor<Executor>::value
+    >::type = 0)
 {
   return executor_work_guard<Executor>(ex);
 }
 
 /// Create an @ref executor_work_guard object.
+/**
+ * @param ctx An execution context, from which an executor will be obtained.
+ *
+ * @returns A work guard constructed with the execution context's executor,
+ * obtained by performing <tt>ctx.get_executor()</tt>.
+ */
 template <typename ExecutionContext>
-inline executor_work_guard<typename ExecutionContext::executor_type>
+BOOST_ASIO_NODISCARD inline
+executor_work_guard<typename ExecutionContext::executor_type>
 make_work_guard(ExecutionContext& ctx,
-    typename enable_if<
-      is_convertible<ExecutionContext&, execution_context&>::value>::type* = 0)
+    typename constraint<
+      is_convertible<ExecutionContext&, execution_context&>::value
+    >::type = 0)
 {
   return executor_work_guard<typename ExecutionContext::executor_type>(
       ctx.get_executor());
 }
 
 /// Create an @ref executor_work_guard object.
+/**
+ * @param t An arbitrary object, such as a completion handler, for which the
+ * associated executor will be obtained.
+ *
+ * @returns A work guard constructed with the associated executor of the object
+ * @c t, which is obtained as if by calling <tt>get_associated_executor(t)</tt>.
+ */
 template <typename T>
-inline executor_work_guard<typename associated_executor<T>::type>
-make_work_guard(const T& t,
-    typename enable_if<!is_executor<T>::value &&
-      !is_convertible<T&, execution_context&>::value>::type* = 0)
+BOOST_ASIO_NODISCARD inline
+executor_work_guard<
+    typename constraint<
+      !is_executor<T>::value
+        && !execution::is_executor<T>::value
+        && !is_convertible<T&, execution_context&>::value,
+      associated_executor<T>
+    >::type::type>
+make_work_guard(const T& t)
 {
   return executor_work_guard<typename associated_executor<T>::type>(
       associated_executor<T>::get(t));
 }
 
 /// Create an @ref executor_work_guard object.
+/**
+ * @param t An arbitrary object, such as a completion handler, for which the
+ * associated executor will be obtained.
+ *
+ * @param ex An executor to be used as the candidate object when determining the
+ * associated executor.
+ *
+ * @returns A work guard constructed with the associated executor of the object
+ * @c t, which is obtained as if by calling <tt>get_associated_executor(t,
+ * ex)</tt>.
+ */
 template <typename T, typename Executor>
-inline executor_work_guard<typename associated_executor<T, Executor>::type>
+BOOST_ASIO_NODISCARD inline
+executor_work_guard<typename associated_executor<T, Executor>::type>
 make_work_guard(const T& t, const Executor& ex,
-    typename enable_if<is_executor<Executor>::value>::type* = 0)
+    typename constraint<
+      is_executor<Executor>::value || execution::is_executor<Executor>::value
+    >::type = 0)
 {
   return executor_work_guard<typename associated_executor<T, Executor>::type>(
       associated_executor<T, Executor>::get(t, ex));
 }
 
 /// Create an @ref executor_work_guard object.
+/**
+ * @param t An arbitrary object, such as a completion handler, for which the
+ * associated executor will be obtained.
+ *
+ * @param ctx An execution context, from which an executor is obtained to use as
+ * the candidate object for determining the associated executor.
+ *
+ * @returns A work guard constructed with the associated executor of the object
+ * @c t, which is obtained as if by calling <tt>get_associated_executor(t,
+ * ctx.get_executor())</tt>.
+ */
 template <typename T, typename ExecutionContext>
-inline executor_work_guard<typename associated_executor<T,
+BOOST_ASIO_NODISCARD inline executor_work_guard<typename associated_executor<T,
   typename ExecutionContext::executor_type>::type>
 make_work_guard(const T& t, ExecutionContext& ctx,
-    typename enable_if<!is_executor<T>::value &&
-      !is_convertible<T&, execution_context&>::value &&
-      is_convertible<ExecutionContext&, execution_context&>::value>::type* = 0)
+    typename constraint<
+      !is_executor<T>::value
+    >::type = 0,
+    typename constraint<
+      !execution::is_executor<T>::value
+    >::type = 0,
+    typename constraint<
+      !is_convertible<T&, execution_context&>::value
+    >::type = 0,
+    typename constraint<
+      is_convertible<ExecutionContext&, execution_context&>::value
+    >::type = 0)
 {
   return executor_work_guard<typename associated_executor<T,
     typename ExecutionContext::executor_type>::type>(