Make the plugin support non-primitive types

plugin/src/InstanceMap.lua

@@ -0,0 +1,71 @@
+local Logging = require(script.Parent.Logging)
+
+--[[
+	A bidirectional map between instance IDs and Roblox instances. It lets us
+	keep track of every instance we know about.
+
+	TODO: Track ancestry to catch when stuff moves?
+]]
+local InstanceMap = {}
+InstanceMap.__index = InstanceMap
+
+function InstanceMap.new()
+	local self = {
+		fromIds = {},
+		fromInstances = {},
+	}
+
+	return setmetatable(self, InstanceMap)
+end
+
+function InstanceMap:insert(id, instance)
+	self.fromIds[id] = instance
+	self.fromInstances[instance] = id
+end
+
+function InstanceMap:removeId(id)
+	local instance = self.fromIds[id]
+
+	if instance ~= nil then
+		self.fromIds[id] = nil
+		self.fromInstances[instance] = nil
+	else
+		Logging.warn("Attempted to remove nonexistant ID %s", tostring(id))
+	end
+end
+
+function InstanceMap:removeInstance(instance)
+	local id = self.fromInstances[instance]
+
+	if id ~= nil then
+		self.fromInstances[instance] = nil
+		self.fromIds[id] = nil
+	else
+		Logging.warn("Attempted to remove nonexistant instance %s", tostring(instance))
+	end
+end
+
+function InstanceMap:destroyId(id)
+	local instance = self.fromIds[id]
+	self:removeId(id)
+
+	if instance ~= nil then
+		local descendantsToDestroy = {}
+
+		for otherInstance in pairs(self.fromInstances) do
+			if otherInstance:IsDescendantOf(instance) then
+				table.insert(descendantsToDestroy, otherInstance)
+			end
+		end
+
+		for _, otherInstance in ipairs(descendantsToDestroy) do
+			self:removeInstance(otherInstance)
+		end
+
+		instance:Destroy()
+	else
+		Logging.warn("Attempted to destroy nonexistant ID %s", tostring(id))
+	end
+end
+
+return InstanceMap