logic: fixed crash when calling message listeners that already have been destroyed

* prevented lambda created by MessageQueue::sendMessageAsTask to call functions on message listeners that already have been destroyed.

src/lib/CMakeLists.txt

@@ -283,6 +283,7 @@ add_files(
 	utility/messaging/Message.h
 	utility/messaging/MessageBase.h
 	utility/messaging/MessageListener.h
+	utility/messaging/MessageListenerBase.cpp
 	utility/messaging/MessageListenerBase.h
 	utility/messaging/MessageQueue.cpp
 	utility/messaging/MessageQueue.h

src/lib/utility/messaging/MessageListenerBase.cpp

@@ -0,0 +1,3 @@
+#include "utility/messaging/MessageListenerBase.h"
+
+uint MessageListenerBase::s_nextId = 0;

src/lib/utility/messaging/MessageListenerBase.h

@@ -5,11 +5,13 @@
 
 #include "utility/messaging/MessageBase.h"
 #include "utility/messaging/MessageQueue.h"
+#include "utility/types.h"
 
 class MessageListenerBase
 {
 public:
 	MessageListenerBase()
+		: m_id(s_nextId++)
 	{
 		MessageQueue::getInstance()->registerListener(this);
 	}
@@ -19,9 +21,19 @@ public:
 		MessageQueue::getInstance()->unregisterListener(this);
 	}
 
+	uint getId() const
+	{
+		return m_id;
+	}
+
 	virtual std::string getType() const = 0;
 
 	virtual void handleMessageBase(MessageBase*) = 0;
+
+private:
+	static uint s_nextId;
+
+	uint m_id;
 };
 
 #endif // MESSAGE_LISTENER_BASE_H

src/lib/utility/messaging/MessageQueue.cpp

@@ -53,6 +53,19 @@ void MessageQueue::unregisterListener(MessageListenerBase* listener)
 	LOG_ERROR("Listener was not found");
 }
 
+MessageListenerBase* MessageQueue::getListenerById(const uint id) const
+{
+	std::lock_guard<std::mutex> lock(m_listenersMutex);
+	for (size_t i = 0; i < m_listeners.size(); i++)
+	{
+		if (m_listeners[i]->getId() == id)
+		{
+			return m_listeners[i];
+		}
+	}
+	return nullptr;
+}
+
 void MessageQueue::pushMessage(std::shared_ptr<MessageBase> message)
 {
 	std::lock_guard<std::mutex> lock(m_backMessageBufferMutex);
@@ -240,10 +253,15 @@ void MessageQueue::sendMessageAsTask(std::shared_ptr<MessageBase> message, bool
 
 		if (listener->getType() == message->getType())
 		{
+			uint listenerId = listener->getId();
 			taskGroup->addTask(std::make_shared<LambdaTask>(
-				[listener, message]()
+				[listenerId, message]()
 				{
-					listener->handleMessageBase(message.get());
+					MessageListenerBase* listener = MessageQueue::getInstance()->getListenerById(listenerId);
+					if (listener)
+					{
+						listener->handleMessageBase(message.get());
+					}
 				}
 			));
 		}

src/lib/utility/messaging/MessageQueue.h

@@ -5,6 +5,8 @@
 #include <mutex>
 #include <queue>
 
+#include "utility/types.h"
+
 class MessageBase;
 class MessageListenerBase;
 
@@ -16,6 +18,8 @@ public:
 	void registerListener(MessageListenerBase* listener);
 	void unregisterListener(MessageListenerBase* listener);
 
+	MessageListenerBase* getListenerById(const uint id) const;
+
 	void pushMessage(std::shared_ptr<MessageBase> message);
 	void processMessage(std::shared_ptr<MessageBase> message, bool asNextTask);