Add some documentation and add map support back

Part of https://github.com/ElunaLuaEngine/Eluna/issues/167

extensions/ObjectVariables.ext

@@ -6,48 +6,62 @@
 
 -- filename.ext files are loaded before normal .lua files
 
+--
+-- This extension allows saving data to specific object for it's lifetime in current runtime session
+-- Supports Map, Player, Creature, GameObject
+--
+-- SetData sets a value
+--  obj:SetData(key, val)
+--
+-- GetData gets the data table or a specific value by key from it
+--  local tbl = obj:GetData()
+--  local val = obj:GetData(key)
+--
+
 local variableStores = {
+    Map = {},
     Player = {},
     Creature = {},
     GameObject = {},
 }
 
-local function DestroyData(event, obj)
-    if event == 18 or event == 17 then
+local function DestroyMapData(event, obj)
     local map = obj:GetMapId()
     local inst = obj:GetInstanceId()
     for k,v in pairs(variableStores) do
-            if inst == 0 then
-                v[map] = nil
-            else
         local mapdata = v[map]
         if mapdata then
             mapdata[inst] = nil
         end
     end
 end
-        return
-    end
-    local mapdata = variableStores[obj:GetObjectType()][obj:GetMapId()]
+
+local function DestroyObjData(event, obj)
+    local map = self:GetMapId()
+    local inst = self:GetInstanceId()
+    local otype = self:GetObjectType()
+    local guid = otype == "Map" and 1 or self:GetGUIDLow()
+    local mapdata = variableStores[otype][map]
     if mapdata then
-        local instancedata = mapdata[obj:GetInstanceId()]
+        local instancedata = mapdata[inst]
         if instancedata then
-            instancedata[obj:GetGUIDLow()] = nil
+            instancedata[guid] = nil
         end
     end
 end
 
 local function GetData(self, field)
-    local varStore = variableStores[self:GetObjectType()]
-    local guid = self:GetGUIDLow()
     local map = self:GetMapId()
     local inst = self:GetInstanceId()
+    local otype = self:GetObjectType()
+    local guid = otype == "Map" and 1 or self:GetGUIDLow()
+    local varStore = variableStores[otype]
 
     varStore[map] = varStore[map] or {}
     varStore[map][inst] = varStore[map][inst] or {}
     varStore[map][inst][guid] = varStore[map][inst][guid] or {}
 
-    if field then
+    if field ~= nil then
         return varStore[map][inst][guid][field]
     else
         return varStore[map][inst][guid]
@@ -55,10 +69,11 @@ local function GetData(self, field)
 end
 
 local function SetData(self, field, val)
-    local varStore = variableStores[self:GetObjectType()]
-    local guid = self:GetGUIDLow()
     local map = self:GetMapId()
     local inst = self:GetInstanceId()
+    local otype = self:GetObjectType()
+    local guid = otype == "Map" and 1 or self:GetGUIDLow()
+    local varStore = variableStores[otype]
 
     varStore[map] = varStore[map] or {}
     varStore[map][inst] = varStore[map][inst] or {}
@@ -72,9 +87,8 @@ for k,v in pairs(variableStores) do
     _G[k].SetData = SetData
 end
 
-RegisterPlayerEvent(3, DestroyData) -- login
-RegisterPlayerEvent(4, DestroyData) -- logout
-RegisterServerEvent(31, DestroyData) -- creature delete
-RegisterServerEvent(32, DestroyData) -- gameobject delete
-RegisterServerEvent(17, DestroyData) -- map create
-RegisterServerEvent(18, DestroyData) -- map destroy
+RegisterPlayerEvent(4, DestroyObjData) -- logout
+RegisterServerEvent(31, DestroyObjData) -- creature delete
+RegisterServerEvent(32, DestroyObjData) -- gameobject delete
+RegisterServerEvent(17, DestroyMapData) -- map create
+RegisterServerEvent(18, DestroyMapData) -- map destroy