add gs

RCCService2018/content/LuaPackages/OtterImpl/createSignal.lua

@@ -0,0 +1,61 @@
+local function addToMap(map, addKey, addValue)
+	local new = {}
+
+	for key, value in pairs(map) do
+		new[key] = value
+	end
+
+	new[addKey] = addValue
+
+	return new
+end
+
+local function removeFromMap(map, removeKey)
+	local new = {}
+
+	for key, value in pairs(map) do
+		if key ~= removeKey then
+			new[key] = value
+		end
+	end
+
+	return new
+end
+
+local function createSignal()
+	local connections = {}
+
+	local function subscribe(self, callback)
+		assert(typeof(callback) == "function", "Can only subscribe to signals with a function.")
+
+		local connection = {
+			callback = callback,
+		}
+
+		connections = addToMap(connections, callback, connection)
+
+		local function disconnect()
+			assert(not connection.disconnected, "Listeners can only be disconnected once.")
+
+			connection.disconnected = true
+			connections = removeFromMap(connections, callback)
+		end
+
+		return disconnect
+	end
+
+	local function fire(self, ...)
+		for callback, connection in pairs(connections) do
+			if not connection.disconnected then
+				callback(...)
+			end
+		end
+	end
+
+	return {
+		subscribe = subscribe,
+		fire = fire,
+	}
+end
+
+return createSignal