so_5::mhood_t< M > Class Template Reference

A message wrapped to be used as type of argument for event handlers. More...

#include <mhood.hpp>

Inheritance diagram for so_5::mhood_t< M >:

Public Member Functions
	mhood_t (message_ref_t &mf)

Private Types
using	base_type_t = details::actual_mhood_base_type<M>

Detailed Description

template<typename M>
class so_5::mhood_t< M >

A message wrapped to be used as type of argument for event handlers.

Since

v.5.5.14

Template Parameters

M	type of message or signal.

Note

This class provides different sets of methods in dependency of type M. If M is a type derived from so_5::message_t, then there will be the following methods for immutable message M:

const M * get() const;
const M * operator->() const;
const M & operator*() const;
so_5::intrusive_ptr_t< M > make_reference() const;
so_5::message_holder_t< M, Ownership > make_holder<Ownership>() const;

If M is a type derived from so_5::signal_t, then there will no be methods at all. It is because there is no actual message object for a signal. If M is user-type message then there will be the following methods for immutable message M:

const M * get() const;
const M * operator->() const;
const M & operator*() const;
so_5::intrusive_ptr_t< so_5::user_type_message_t<M> > make_reference() const;
so_5::message_holder_t< M, Ownership > make_holder<Ownership>() const;

For mutable message M there will be the following methods is M is derived from so_5::message_t:

M * get();
M * operator->();
M & operator*();
so_5::intrusive_ptr_t< M > make_reference();
so_5::message_holder_t< M, Ownership > make_holder<Ownership>();

If mutable message M is not derived from so_5::message_t then there will be the following methods:

M * get();
M * operator->();
M & operator*();
so_5::intrusive_ptr_t< so_5::user_type_message_t<M> > make_reference();
so_5::message_holder_t< M, Ownership > make_holder<Ownership>();

Method make_holder() uses so_5::message_ownership_t::autodetected by default.

Attention

Methods make_reference() for mhood_t<mutable_msg<M>> will leave mhood object in nullptr state. It means that mhood must not be used after calling make_reference().

Methods make_holder() for mhood_t<mutable_msg<M>> will leave the mhood object empty always. Regardless of Ownership parameter. Methods make_holder() for mhood_t<M> and mhood_t<immutable_msg<M>> will leave value for mhood object regardless of Ownership parameter. For example:

class demo : public agent_t {
 void on_immutable_msg(mhood_t<some_msg> cmd) {
   auto unique_holder = cmd.make_holder<so_5::message_ownership_t::unique>();
   auto v = cmd->some_value(); // cmd still has its value.
   ...
 }
   ...
   void on_mutable_msg(mhood_t< mutable_msg<another_msg> > cmd) {
   auto shared_holder = cmd.make_holder<so_5::message_ownership_t::shared>();
   // Now cmd is empty!
   auto v = cmd->some_value(); // THIS IS UB!  
   }
};

Note

Class mhood_t can be used for redirection of messages of user types. For example (since v.5.5.19):

class redirector : public so_5::agent_t
{
  ...
  void some_event( mhood_t< std::string > evt ) {
    // Redirection of message to the different mbox.
    so_5::send(m_another_mbox, evt);
  }
};

If mhood_t<mutable_msg<M>> is used then a redirection must be done this way:

class redirector : public so_5::agent_t
{
  ...
  void some_event( mhood_t< mutable_msg<std::string> > evt ) {
    // Redirection of message to the different mbox.
    so_5::send(m_another_mbox, std::move(evt));
    // NOTE: evt is nullptr at this point. It must not be used anymore.
  }
};

Examples

so_5/delivery_filters/main.cpp, so_5/make_pipeline/main.cpp, so_5/mchain_handler_formats/main.cpp, so_5/news_board/main.cpp, so_5/prio_work_stealing/main.cpp, so_5/queue_size_stats/main.cpp, and so_5/wrapped_env_demo_3/main.cpp.

Definition at line 568 of file mhood.hpp.

Member Typedef Documentation

base_type_t

template<typename M >

using so_5::mhood_t< M >::base_type_t = details::actual_mhood_base_type<M>

private

Definition at line 571 of file mhood.hpp.

Constructor & Destructor Documentation

mhood_t()

template<typename M >

so_5::mhood_t< M >::mhood_t ( message_ref_t & mf )

inline

Definition at line 574 of file mhood.hpp.

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The documentation for this class was generated from the following file:

• mhood.hpp