Add try_send_via_dispatch/try_send_n_via_dispatch functions to channels.

include/boost/asio/experimental/basic_channel.hpp

@@ -338,13 +338,37 @@ class basic_channel
   template <typename... Args>
   bool try_send(Args&&... args);
 
+  /// Try to send a message without blocking, using dispatch semantics to call
+  /// the receive operation's completion handler.
+  /**
+   * Fails if the buffer is full and there are no waiting receive operations.
+   *
+   * The receive operation's completion handler may be called from inside this
+   * function.
+   *
+   * @returns @c true on success, @c false on failure.
+   */
+  template <typename... Args>
+  bool try_send_via_dispatch(Args&&... args);
+
   /// Try to send a number of messages without blocking.
   /**
    * @returns The number of messages that were sent.
    */
   template <typename... Args>
   std::size_t try_send_n(std::size_t count, Args&&... args);
 
+  /// Try to send a number of messages without blocking, using dispatch
+  /// semantics to call the receive operations' completion handlers.
+  /**
+   * The receive operations' completion handlers may be called from inside this
+   * function.
+   *
+   * @returns The number of messages that were sent.
+   */
+  template <typename... Args>
+  std::size_t try_send_n_via_dispatch(std::size_t count, Args&&... args);
+
   /// Asynchronously send a message.
   /**
    * @par Completion Signature

include/boost/asio/experimental/basic_concurrent_channel.hpp

@@ -345,13 +345,37 @@ class basic_concurrent_channel
   template <typename... Args>
   bool try_send(Args&&... args);
 
+  /// Try to send a message without blocking, using dispatch semantics to call
+  /// the receive operation's completion handler.
+  /**
+   * Fails if the buffer is full and there are no waiting receive operations.
+   *
+   * The receive operation's completion handler may be called from inside this
+   * function.
+   *
+   * @returns @c true on success, @c false on failure.
+   */
+  template <typename... Args>
+  bool try_send_via_dispatch(Args&&... args);
+
   /// Try to send a number of messages without blocking.
   /**
    * @returns The number of messages that were sent.
    */
   template <typename... Args>
   std::size_t try_send_n(std::size_t count, Args&&... args);
 
+  /// Try to send a number of messages without blocking, using dispatch
+  /// semantics to call the receive operations' completion handlers.
+  /**
+   * The receive operations' completion handlers may be called from inside this
+   * function.
+   *
+   * @returns The number of messages that were sent.
+   */
+  template <typename... Args>
+  std::size_t try_send_n_via_dispatch(std::size_t count, Args&&... args);
+
   /// Asynchronously send a message.
   template <typename... Args,
       BOOST_ASIO_COMPLETION_TOKEN_FOR(void (boost::system::error_code))

include/boost/asio/experimental/detail/channel_operation.hpp

@@ -56,9 +56,10 @@ class channel_operation BOOST_ASIO_INHERIT_TRACKED_HANDLER
   {
     destroy_op = 0,
     immediate_op = 1,
-    complete_op = 2,
-    cancel_op = 3,
-    close_op = 4
+    post_op = 2,
+    dispatch_op = 3,
+    cancel_op = 4,
+    close_op = 5
   };
 
   typedef void (*func_type)(channel_operation*, action, void*);
@@ -116,6 +117,17 @@ class channel_operation::handler_work_base
       ).execute(static_cast<Function&&>(function));
   }
 
+  template <typename Function, typename Handler>
+  void dispatch(Function& function, Handler& handler)
+  {
+    associated_allocator_t<Handler> allocator =
+      (get_associated_allocator)(handler);
+
+    boost::asio::prefer(executor_,
+        execution::allocator(allocator)
+      ).execute(static_cast<Function&&>(function));
+  }
+
 private:
   executor_type executor_;
 };
@@ -151,6 +163,16 @@ class channel_operation::handler_work_base<Executor,
         static_cast<Function&&>(function), allocator);
   }
 
+  template <typename Function, typename Handler>
+  void dispatch(Function& function, Handler& handler)
+  {
+    associated_allocator_t<Handler> allocator =
+      (get_associated_allocator)(handler);
+
+    work_.get_executor().dispatch(
+        static_cast<Function&&>(function), allocator);
+  }
+
 private:
   executor_work_guard<Executor> work_;
 };
@@ -177,11 +199,17 @@ class channel_operation::handler_work :
   }
 
   template <typename Function>
-  void complete(Function& function, Handler& handler)
+  void post(Function& function, Handler& handler)
   {
     base2_type::post(function, handler);
   }
 
+  template <typename Function>
+  void dispatch(Function& function, Handler& handler)
+  {
+    base2_type::dispatch(function, handler);
+  }
+
   template <typename Function>
   void immediate(Function& function, Handler& handler, ...)
   {
@@ -234,11 +262,17 @@ class channel_operation::handler_work<
   }
 
   template <typename Function>
-  void complete(Function& function, Handler& handler)
+  void post(Function& function, Handler& handler)
   {
     base1_type::post(function, handler);
   }
 
+  template <typename Function>
+  void dispatch(Function& function, Handler& handler)
+  {
+    base1_type::dispatch(function, handler);
+  }
+
   template <typename Function>
   void immediate(Function& function, Handler& handler, ...)
   {

include/boost/asio/experimental/detail/channel_receive_op.hpp

@@ -39,9 +39,14 @@ class channel_receive : public channel_operation
     func_(this, immediate_op, &payload);
   }
 
-  void complete(Payload payload)
+  void post(Payload payload)
   {
-    func_(this, complete_op, &payload);
+    func_(this, post_op, &payload);
+  }
+
+  void dispatch(Payload payload)
+  {
+    func_(this, dispatch_op, &payload);
   }
 
 protected:
@@ -95,8 +100,10 @@ class channel_receive_op : public channel_receive<Payload>
       BOOST_ASIO_HANDLER_INVOCATION_BEGIN(());
       if (a == channel_operation::immediate_op)
         w.immediate(handler, handler.handler_, 0);
+      else if (a == channel_operation::dispatch_op)
+        w.dispatch(handler, handler.handler_);
       else
-        w.complete(handler, handler.handler_);
+        w.post(handler, handler.handler_);
       BOOST_ASIO_HANDLER_INVOCATION_END;
     }
     else

include/boost/asio/experimental/detail/channel_send_functions.hpp

@@ -44,7 +44,19 @@ class channel_send_functions<Derived, Executor, R(Args...)>
     typedef typename detail::channel_message<R(Args...)> message_type;
     Derived* self = static_cast<Derived*>(this);
     return self->service_->template try_send<message_type>(
-        self->impl_, static_cast<Args2&&>(args)...);
+        self->impl_, false, static_cast<Args2&&>(args)...);
+  }
+
+  template <typename... Args2>
+  enable_if_t<
+    is_constructible<detail::channel_message<R(Args...)>, int, Args2...>::value,
+    bool
+  > try_send_via_dispatch(Args2&&... args)
+  {
+    typedef typename detail::channel_message<R(Args...)> message_type;
+    Derived* self = static_cast<Derived*>(this);
+    return self->service_->template try_send<message_type>(
+        self->impl_, true, static_cast<Args2&&>(args)...);
   }
 
   template <typename... Args2>
@@ -56,7 +68,19 @@ class channel_send_functions<Derived, Executor, R(Args...)>
     typedef typename detail::channel_message<R(Args...)> message_type;
     Derived* self = static_cast<Derived*>(this);
     return self->service_->template try_send_n<message_type>(
-        self->impl_, count, static_cast<Args2&&>(args)...);
+        self->impl_, count, false, static_cast<Args2&&>(args)...);
+  }
+
+  template <typename... Args2>
+  enable_if_t<
+    is_constructible<detail::channel_message<R(Args...)>, int, Args2...>::value,
+    std::size_t
+  > try_send_n_via_dispatch(std::size_t count, Args2&&... args)
+  {
+    typedef typename detail::channel_message<R(Args...)> message_type;
+    Derived* self = static_cast<Derived*>(this);
+    return self->service_->template try_send_n<message_type>(
+        self->impl_, count, true, static_cast<Args2&&>(args)...);
   }
 
   template <
@@ -99,7 +123,19 @@ class channel_send_functions<Derived, Executor, R(Args...), Signatures...> :
     typedef typename detail::channel_message<R(Args...)> message_type;
     Derived* self = static_cast<Derived*>(this);
     return self->service_->template try_send<message_type>(
-        self->impl_, static_cast<Args2&&>(args)...);
+        self->impl_, false, static_cast<Args2&&>(args)...);
+  }
+
+  template <typename... Args2>
+  enable_if_t<
+    is_constructible<detail::channel_message<R(Args...)>, int, Args2...>::value,
+    bool
+  > try_send_via_dispatch(Args2&&... args)
+  {
+    typedef typename detail::channel_message<R(Args...)> message_type;
+    Derived* self = static_cast<Derived*>(this);
+    return self->service_->template try_send<message_type>(
+        self->impl_, true, static_cast<Args2&&>(args)...);
   }
 
   template <typename... Args2>
@@ -111,7 +147,19 @@ class channel_send_functions<Derived, Executor, R(Args...), Signatures...> :
     typedef typename detail::channel_message<R(Args...)> message_type;
     Derived* self = static_cast<Derived*>(this);
     return self->service_->template try_send_n<message_type>(
-        self->impl_, count, static_cast<Args2&&>(args)...);
+        self->impl_, count, false, static_cast<Args2&&>(args)...);
+  }
+
+  template <typename... Args2>
+  enable_if_t<
+    is_constructible<detail::channel_message<R(Args...)>, int, Args2...>::value,
+    std::size_t
+  > try_send_n_via_dispatch(std::size_t count, Args2&&... args)
+  {
+    typedef typename detail::channel_message<R(Args...)> message_type;
+    Derived* self = static_cast<Derived*>(this);
+    return self->service_->template try_send_n<message_type>(
+        self->impl_, count, true, static_cast<Args2&&>(args)...);
   }
 
   template <

include/boost/asio/experimental/detail/channel_send_op.hpp

@@ -44,9 +44,9 @@ class channel_send : public channel_operation
     func_(this, immediate_op, 0);
   }
 
-  void complete()
+  void post()
   {
-    func_(this, complete_op, 0);
+    func_(this, post_op, 0);
   }
 
   void cancel()
@@ -130,7 +130,7 @@ class channel_send_op : public channel_send<Payload>
       if (a == channel_operation::immediate_op)
         w.immediate(handler, handler.handler_, 0);
       else
-        w.complete(handler, handler.handler_);
+        w.post(handler, handler.handler_);
       BOOST_ASIO_HANDLER_INVOCATION_END;
     }
   }

include/boost/asio/experimental/detail/channel_service.hpp

@@ -138,13 +138,13 @@ class channel_service
   template <typename Message, typename Traits,
       typename... Signatures, typename... Args>
   bool try_send(implementation_type<Traits, Signatures...>& impl,
-      Args&&... args);
+      bool via_dispatch, Args&&... args);
 
   // Synchronously send a number of new values into the channel.
   template <typename Message, typename Traits,
       typename... Signatures, typename... Args>
   std::size_t try_send_n(implementation_type<Traits, Signatures...>& impl,
-      std::size_t count, Args&&... args);
+      std::size_t count, bool via_dispatch, Args&&... args);
 
   // Asynchronously send a new value into the channel.
   template <typename Traits, typename... Signatures,
@@ -221,17 +221,17 @@ class channel_service
 private:
   // Helper function object to handle a closed notification.
   template <typename Payload, typename Signature>
-  struct complete_receive
+  struct post_receive
   {
-    explicit complete_receive(channel_receive<Payload>* op)
+    explicit post_receive(channel_receive<Payload>* op)
       : op_(op)
     {
     }
 
     template <typename... Args>
     void operator()(Args&&... args)
     {
-      op_->complete(
+      op_->post(
           channel_message<Signature>(0,
             static_cast<Args&&>(args)...));
     }