Solve #182 add table pool for events

druid/system/druid_instance.lua

@@ -289,6 +289,7 @@ function DruidInstance.remove(self, component)
 	local all_components = self.components_all
 	for i = #all_components, 1, -1 do
 		if all_components[i] == component then
+			component:on_internal_remove()
 			if component.on_remove then
 				component:on_remove()
 			end

druid/system/tablepool.lua

@@ -0,0 +1,75 @@
+-- Source: https://github.com/openresty/lua-tablepool/blob/master/lib/tablepool.lua
+
+local setmetatable = setmetatable
+
+local _M = {}
+local max_pool_size = 500
+local pools = {}
+
+
+function _M.fetch(tag)
+    local pool = pools[tag]
+    if not pool then
+        pool = {}
+        pools[tag] = pool
+        pool.c = 0
+        pool[0] = 0
+
+    else
+        local len = pool[0]
+        if len > 0 then
+            local obj = pool[len]
+            pool[len] = nil
+            pool[0] = len - 1
+            return obj
+        end
+    end
+
+    return {}
+end
+
+
+function _M.release(tag, obj, noclear)
+    if not obj then
+        error("object empty", 2)
+    end
+
+    local pool = pools[tag]
+    if not pool then
+        pool = {}
+        pools[tag] = pool
+        pool.c = 0
+        pool[0] = 0
+    end
+
+    if not noclear then
+        setmetatable(obj, nil)
+        for k in pairs(obj) do
+            obj[k] = nil
+        end
+    end
+
+    do
+        local cnt = pool.c + 1
+        if cnt >= 20000 then
+            pool = {}
+            pools[tag] = pool
+            pool.c = 0
+            pool[0] = 0
+            return
+        end
+        pool.c = cnt
+    end
+
+    local len = pool[0] + 1
+    if len > max_pool_size then
+        -- discard it simply
+        return
+    end
+
+    pool[len] = obj
+    pool[0] = len
+end
+
+
+return _M