Introduce `ObjectNamesMutex` helper class

lib/remote/apilistener-configsync.cpp

@@ -462,3 +462,37 @@ void ApiListener::SendRuntimeConfigObjects(const JsonRpcConnection::Ptr& aclient
 	Log(LogInformation, "ApiListener")
 		<< "Finished syncing runtime objects to endpoint '" << endpoint->GetName() << "'.";
 }
+
+/**
+ * Locks the specified object name of the given type. If it is already locked, the call blocks until the lock is released.
+ *
+ * @param Type::Ptr ptype The type of the object you want to lock
+ * @param String objName The object name you want to lock
+ */
+void ObjectNameMutex::Lock(const Type::Ptr& ptype, const String& objName)
+{
+	std::unique_lock<std::mutex> lock(m_Mutex);
+	m_CV.wait(lock, [this, &ptype, &objName]{
+		auto& locked = m_LockedObjectNames[ptype.get()];
+		return locked.find(objName) == locked.end();
+	});
+
+	// Add object name to the locked list again to block all other threads that try
+	// to process a message affecting the same object.
+	m_LockedObjectNames[ptype.get()].emplace(objName);
+}
+
+/**
+ * Unlocks the specified object name of the given type.
+ *
+ * @param Type::Ptr ptype The type of the object you want to unlock
+ * @param String objName The name of the object you want to unlock
+ */
+void ObjectNameMutex::Unlock(const Type::Ptr& ptype, const String& objName)
+{
+	{
+		std::unique_lock<std::mutex> lock(m_Mutex);
+		m_LockedObjectNames[ptype.get()].erase(objName);
+	}
+	m_CV.notify_all();
+}

lib/remote/apilistener.hpp

@@ -71,6 +71,26 @@ enum class ApiCapabilities : uint_fast64_t
 	IfwApiCheckCommand = 1u << 1u,
 };
 
+/**
+ * Allows you to easily lock/unlock a specific object of a given type by its name.
+ *
+ * That way, locking an object "this" of type Host does not affect an object "this" of
+ * type "Service" nor an object "other" of type "Host".
+ *
+ * @ingroup remote
+ */
+class ObjectNameMutex
+{
+public:
+	void Lock(const Type::Ptr& ptype, const String& objName);
+	void Unlock(const Type::Ptr& ptype, const String& objName);
+
+private:
+	std::mutex m_Mutex;
+	std::condition_variable m_CV;
+	std::map<Type*, std::set<String>> m_LockedObjectNames;
+};
+
 /**
 * @ingroup remote
 */