add gs

RCCService2018/content/LuaPackages/RoduxImpl/Signal.lua

@@ -0,0 +1,75 @@
+--[[
+	A limited, simple implementation of a Signal.
+
+	Handlers are fired in order, and (dis)connections are properly handled when
+	executing an event.
+]]
+
+local function immutableAppend(list, ...)
+	local new = {}
+	local len = #list
+
+	for key = 1, len do
+		new[key] = list[key]
+	end
+
+	for i = 1, select("#", ...) do
+		new[len + i] = select(i, ...)
+	end
+
+	return new
+end
+
+local function immutableRemoveValue(list, removeValue)
+	local new = {}
+
+	for i = 1, #list do
+		if list[i] ~= removeValue then
+			table.insert(new, list[i])
+		end
+	end
+
+	return new
+end
+
+local Signal = {}
+
+Signal.__index = Signal
+
+function Signal.new()
+	local self = {
+		_listeners = {}
+	}
+
+	setmetatable(self, Signal)
+
+	return self
+end
+
+function Signal:connect(callback)
+	local listener = {
+		callback = callback,
+		disconnected = false,
+	}
+
+	self._listeners = immutableAppend(self._listeners, listener)
+
+	local function disconnect()
+		listener.disconnected = true
+		self._listeners = immutableRemoveValue(self._listeners, listener)
+	end
+
+	return {
+		disconnect = disconnect
+	}
+end
+
+function Signal:fire(...)
+	for _, listener in ipairs(self._listeners) do
+		if not listener.disconnected then
+			listener.callback(...)
+		end
+	end
+end
+
+return Signal