The very first step in resolving #71.

A draft version of agent_t::so_this_agent_disp_binder() and a unit-test
for it.

dev/so_5/agent.hpp

@@ -2604,6 +2604,14 @@ class SO_5_TYPE agent_t
 				return lambda();
 			}
 
+		//FIXME: document this!
+		[[nodiscard]]
+		disp_binder_shptr_t
+		so_this_agent_disp_binder() const
+			{
+				return m_disp_binder;
+			}
+
 	private:
 		const state_t st_default{ self_ptr(), "<DEFAULT>" };
 

dev/test/so_5/coop/CMakeLists.txt

@@ -25,3 +25,4 @@ add_subdirectory(child_coop_map)
 add_subdirectory(issue_28)
 add_subdirectory(msg_loss_at_registration)
 add_subdirectory(destruction_order_1)
+add_subdirectory(this_agent_disp_binder)

dev/test/so_5/coop/build_tests.rb

@@ -32,5 +32,6 @@
 	required_prj( "#{path}/issue_28/prj.ut.rb" )
 	required_prj( "#{path}/msg_loss_at_registration/prj.ut.rb" )
 	required_prj( "#{path}/destruction_order_1/prj.ut.rb" )
+	required_prj( "#{path}/this_agent_disp_binder/prj.ut.rb" )
 }
 

dev/test/so_5/coop/this_agent_disp_binder/CMakeLists.txt

@@ -0,0 +1,2 @@
+set(UNITTEST _unit.test.coop.this_agent_disp_binder)
+include(${CMAKE_SOURCE_DIR}/cmake/unittest.cmake)

dev/test/so_5/coop/this_agent_disp_binder/main.cpp

@@ -0,0 +1,145 @@
+/*
+ * A unit-test for agent_t::so_this_agent_disp_binder().
+ */
+
+#include <so_5/all.hpp>
+
+#include <test/3rd_party/various_helpers/ensure.hpp>
+#include <test/3rd_party/various_helpers/time_limited_execution.hpp>
+
+namespace test
+{
+
+struct msg_done final : public so_5::signal_t {};
+
+struct msg_take_tid final : public so_5::message_t
+	{
+		so_5::current_thread_id_t m_tid;
+
+		explicit msg_take_tid( so_5::current_thread_id_t tid )
+			:	m_tid{ tid }
+			{}
+	};
+
+class a_collector_t final : public so_5::agent_t
+	{
+		std::set< so_5::current_thread_id_t > m_tids;
+
+	public:
+		using so_5::agent_t::agent_t;
+
+		void
+		so_define_agent() override
+			{
+				so_subscribe_self()
+					.event( &a_collector_t::evt_done )
+					.event( &a_collector_t::evt_take_tid )
+					;
+			}
+
+		void
+		so_evt_start() override
+			{
+				so_5::send< msg_take_tid >( *this, so_5::query_current_thread_id() );
+			}
+
+		void
+		so_evt_finish() override
+			{
+				ensure_or_die( 3u == m_tids.size(),
+						"unexpected number of collected TIDs: " +
+						std::to_string( m_tids.size() ) );
+			}
+
+	private:
+		void
+		evt_done( mhood_t< msg_done > )
+			{
+				so_deregister_agent_coop_normally();
+			}
+
+		void
+		evt_take_tid( mhood_t< msg_take_tid > cmd )
+			{
+				m_tids.insert( cmd->m_tid );
+			}
+	};
+
+class a_child_t final : public so_5::agent_t
+	{
+		const so_5::mbox_t m_collector_mbox;
+
+	public:
+		a_child_t( context_t ctx, so_5::mbox_t collector_mbox )
+			:	so_5::agent_t{ std::move(ctx) }
+			,	m_collector_mbox{ std::move(collector_mbox) }
+			{}
+
+		void
+		so_evt_start() override
+			{
+				so_5::send< msg_take_tid >( m_collector_mbox,
+						so_5::query_current_thread_id() );
+				so_5::send< msg_done >( m_collector_mbox );
+			}
+	};
+
+class a_parent_t final : public so_5::agent_t
+	{
+		const so_5::mbox_t m_collector_mbox;
+
+	public:
+		a_parent_t( context_t ctx, so_5::mbox_t collector_mbox )
+			:	so_5::agent_t{ std::move(ctx) }
+			,	m_collector_mbox{ std::move(collector_mbox) }
+			{}
+
+		void
+		so_evt_start() override
+			{
+				so_5::send< msg_take_tid >( m_collector_mbox,
+						so_5::query_current_thread_id() );
+
+				so_5::introduce_child_coop(
+						*this,
+						so_this_agent_disp_binder(),
+						[this]( so_5::coop_t & coop ) {
+							coop.make_agent< a_child_t >( m_collector_mbox );
+						} );
+			}
+	};
+
+void
+init( so_5::environment_t & env )
+{
+	env.introduce_coop( [&]( so_5::coop_t & coop ) {
+			// The collector will use the default dispatcher
+			// (because it's automatically selected for the coop).
+			auto mbox = coop.make_agent< a_collector_t >()->so_direct_mbox();
+
+			// The parent agent will use active_obj dispatcher.
+			coop.make_agent_with_binder< a_parent_t >(
+					so_5::disp::active_obj::make_dispatcher( env ).binder(),
+					mbox );
+		} );
+}
+
+} /* namespace test */
+
+int
+main()
+{
+	try
+	{
+		run_with_time_limit( []{ so_5::launch( test::init ); }, 5 );
+
+		return 0;
+	}
+	catch( const std::exception & x )
+	{
+		std::cerr << "Exception: " << x.what() << std::endl;
+	}
+
+	return 2;
+}
+

dev/test/so_5/coop/this_agent_disp_binder/prj.rb

@@ -0,0 +1,11 @@
+require 'mxx_ru/cpp'
+
+MxxRu::Cpp::exe_target {
+
+	required_prj 'so_5/prj.rb'
+
+	target '_unit.test.coop.this_agent_disp_binder'
+
+	cpp_source 'main.cpp'
+}
+

dev/test/so_5/coop/this_agent_disp_binder/prj.ut.rb

@@ -0,0 +1,9 @@
+require 'mxx_ru/binary_unittest'
+
+path = 'test/so_5/coop/this_agent_disp_binder'
+
+MxxRu::setup_target(
+	MxxRu::BinaryUnittestTarget.new(
+		"#{path}/prj.ut.rb",
+		"#{path}/prj.rb" )
+)