Remove Subscriber and make Listener more safe

There could be not nice situation when bus dies and Listener wants to unlisten. That was easy to
achieve e.g. bad order in class fields. (Order of destruction matters)

lib/CMakeLists.txt

@@ -46,9 +46,8 @@ add_library(EventBus
 	# New version of EventBus 3.0
 	include/dexode/EventBus.hpp
 	include/dexode/eventbus/Listener.hpp
-	include/dexode/eventbus/Subscriber.hpp
 	src/dexode/eventbus/strategy/Protected.cpp include/dexode/eventbus/strategy/Protected.hpp
-	src/dexode/eventbus/strategy/Transaction.cpp include/dexode/eventbus/strategy/Transaction.hpp
+	include/dexode/eventbus/strategy/Transaction.hpp
 	)
 add_library(Dexode::EventBus ALIAS EventBus)
 
@@ -63,7 +62,6 @@ target_include_directories(EventBus PUBLIC
 set(EventBus_PUBLIC_HEADERS
 	include/dexode/EventBus.hpp
 	include/dexode/eventbus/Listener.hpp
-	include/dexode/eventbus/Subscriber.hpp
 	include/dexode/eventbus/strategy/Protected.hpp
 	include/dexode/eventbus/strategy/Transaction.hpp
 	)

lib/include/dexode/EventBus.hpp

@@ -9,7 +9,6 @@
 #include <eventbus/EventBus.h>
 
 #include "eventbus/Listener.hpp"
-#include "eventbus/Subscriber.hpp"
 #include "eventbus/internal/common.h"
 
 namespace dexode
@@ -22,7 +21,6 @@ class EventBus
 
 public:
 	using Listener = eventbus::Listener<EventBus<Strategy>>;
-	using Subscriber = eventbus::Subscriber<EventBus<Strategy>>;
 
 	constexpr EventBus() = default;
 	~EventBus() = default;
@@ -33,11 +31,6 @@ public:
 	EventBus& operator=(EventBus&&) = delete;
 	EventBus& operator=(const EventBus&) = delete;
 
-	Listener createListener()
-	{
-		return Listener{*this};
-	}
-
 	template <typename Event>
 	constexpr void post(const Event& event)
 	{

lib/include/dexode/eventbus/Listener.hpp

@@ -13,20 +13,17 @@ class Listener
 public:
 	explicit Listener() = default; // Dummy listener
 
-	explicit Listener(Bus& bus)
-		: _id{bus.newListenerID()}
-		, _bus{&bus}
+	explicit Listener(std::shared_ptr<Bus> bus)
+		: _id{bus->newListenerID()}
+		, _bus{std::move(bus)}
 	{}
 
 	Listener(const Listener& other) = delete;
 
 	Listener(Listener&& other)
 		: _id(other._id)
-		, _bus(other._bus)
-	{
-		other._id = 0;
-		other._bus = nullptr;
-	}
+		, _bus(std::move(other._bus))
+	{}
 
 	~Listener()
 	{
@@ -38,7 +35,7 @@ public:
 
 	Listener& operator=(const Listener& other) = delete;
 
-	Listener& operator=(Listener&& other)
+	Listener& operator=(Listener&& other) noexcept
 	{
 		if(this == &other)
 		{
@@ -47,12 +44,10 @@ public:
 
 		if(_bus != nullptr)
 		{
-			unlistenAll();
+			unlistenAll(); // remove previous
 		}
 		_id = other._id;
-		other._id = 0;
-		_bus = other._bus;
-		other._bus = nullptr;
+		_bus = std::move(other._bus);
 
 		return *this;
 	}
@@ -68,16 +63,6 @@ public:
 									 std::forward<std::function<void(const Event&)>>(callback));
 	}
 
-	template <class Event>
-	void listen(const std::function<void(const Event&)>& callback)
-	{
-		if(_bus == nullptr)
-		{
-			throw std::runtime_error{"bus is null"};
-		}
-		_bus->template listen<Event>(_id, callback);
-	}
-
 	void unlistenAll()
 	{
 		if(_bus == nullptr)
@@ -99,7 +84,7 @@ public:
 
 private:
 	std::uint32_t _id = 0;
-	Bus* _bus = nullptr;
+	std::shared_ptr<Bus> _bus = nullptr;
 };
 
 } // namespace dexode::eventbus

lib/include/dexode/eventbus/Subscriber.hpp

@@ -1,71 +0,0 @@
-#pragma once
-
-#include "dexode/EventBus.hpp"
-
-namespace dexode::eventbus
-{
-template <class Bus>
-class Subscriber
-{
-public:
-	Subscriber(std::shared_ptr<Bus> retainBus)
-		: _listener{*retainBus}
-		, _bus{std::move(retainBus)}
-	{}
-
-	Subscriber(Subscriber&& other)
-		: _listener(std::move(other._listener))
-		, _bus(std::move(other._bus))
-	{}
-
-	~Subscriber()
-	{
-		unlistenAll(); // extra safety if order of members is inverse
-	}
-
-	Subscriber& operator=(Subscriber&& other)
-	{
-		if(this == &other)
-		{
-			return *this;
-		}
-
-		_listener = std::move(other._listener);
-		_bus = std::move(other._bus);
-
-		return *this;
-	}
-
-	template <class Event>
-	void listen(std::function<void(const Event&)>&& callback)
-	{
-		_listener.template listen<Event>(std::forward<std::function<void(const Event&)>>(callback));
-	}
-
-	template <class Event>
-	void listen(const std::function<void(const Event&)>& callback)
-	{
-		_listener.template listen<Event>(callback);
-	}
-
-	void unlistenAll()
-	{
-		_listener.unlistenAll();
-	}
-
-	template <typename Event>
-	void unlisten()
-	{
-		_listener.template unlisten<Event>();
-	}
-
-	const std::shared_ptr<Bus>& getEventBus() const
-	{
-		return _bus;
-	}
-
-private:
-	Listener<Bus> _listener;
-	std::shared_ptr<Bus> _bus; // own
-};
-} // namespace dexode::eventbus

lib/src/dexode/eventbus/strategy/Transaction.cpp

@@ -1,6 +0,0 @@
-#include "dexode/eventbus/strategy/Transaction.hpp"
-
-namespace dexode::eventbus::strategy
-{
-
-}