From dff522fbaa8775ed983f6a2b83409addef7d112d Mon Sep 17 00:00:00 2001
From: Insality <insality@gmail.com>
Date: Tue, 5 Apr 2022 18:57:40 +0300
Subject: [PATCH] Solve #182 add table pool for events

---
 druid/base/back_handler.lua       |  6 +++
 druid/base/button.lua             | 11 +++++
 druid/base/drag.lua               | 10 +++++
 druid/base/hover.lua              |  7 +++
 druid/base/scroll.lua             |  8 ++++
 druid/base/static_grid.lua        | 10 +++++
 druid/base/swipe.lua              |  6 +++
 druid/base/text.lua               |  8 ++++
 druid/component.lua               |  6 +++
 druid/const.lua                   |  2 +
 druid/event.lua                   | 22 ++++++---
 druid/extended/checkbox.lua       |  6 +++
 druid/extended/checkbox_group.lua |  7 +++
 druid/extended/data_list.lua      |  6 +++
 druid/extended/dynamic_grid.lua   | 10 +++++
 druid/extended/input.lua          | 11 +++++
 druid/extended/lang_text.lua      |  6 +++
 druid/extended/layout.lua         |  6 +++
 druid/extended/progress.lua       |  6 +++
 druid/extended/radio_group.lua    |  6 +++
 druid/extended/slider.lua         |  6 +++
 druid/extended/timer.lua          |  8 ++++
 druid/system/druid_instance.lua   |  1 +
 druid/system/tablepool.lua        | 75 +++++++++++++++++++++++++++++++
 24 files changed, 244 insertions(+), 6 deletions(-)
 create mode 100644 druid/system/tablepool.lua

diff --git a/druid/base/back_handler.lua b/druid/base/back_handler.lua
index a97c7d8..e3e19c8 100644
--- a/druid/base/back_handler.lua
+++ b/druid/base/back_handler.lua
@@ -30,6 +30,12 @@ function BackHandler.init(self, callback, params)
 end
 
 
+function BackHandler.on_internal_remove(self)
+	component.on_internal_remove(self)
+	self.on_back:clear()
+end
+
+
 --- Input handler for component
 -- @tparam BackHandler self @{BackHandler}
 -- @tparam string action_id on_input action id
diff --git a/druid/base/button.lua b/druid/base/button.lua
index 61c4db2..fe41c4d 100755
--- a/druid/base/button.lua
+++ b/druid/base/button.lua
@@ -239,6 +239,17 @@ function Button.on_late_init(self)
 end
 
 
+function Button.on_internal_remove(self)
+	component.on_internal_remove(self)
+	self.on_click:clear()
+	self.on_repeated_click:clear()
+	self.on_long_click:clear()
+	self.on_double_click:clear()
+	self.on_hold_callback:clear()
+	self.on_click_outside:clear()
+end
+
+
 function Button.on_input(self, action_id, action)
 	if not is_input_match(self, action_id) then
 		return false
diff --git a/druid/base/drag.lua b/druid/base/drag.lua
index b51c1af..c9c2e98 100644
--- a/druid/base/drag.lua
+++ b/druid/base/drag.lua
@@ -189,6 +189,16 @@ function Drag.init(self, node, on_drag_callback)
 end
 
 
+function Drag.on_internal_remove(self)
+	component.on_internal_remove(self)
+	self.on_touch_start:clear()
+	self.on_touch_end:clear()
+	self.on_drag_start:clear()
+	self.on_drag:clear()
+	self.on_drag_end:clear()
+end
+
+
 function Drag.on_late_init(self)
 	if not self.click_zone and const.IS_STENCIL_CHECK then
 		local stencil_node = helper.get_closest_stencil_node(self.node)
diff --git a/druid/base/hover.lua b/druid/base/hover.lua
index 05aa0ac..9c71b18 100644
--- a/druid/base/hover.lua
+++ b/druid/base/hover.lua
@@ -38,6 +38,13 @@ function Hover.init(self, node, on_hover_callback)
 end
 
 
+function Hover.on_internal_remove(self)
+	component.on_internal_remove(self)
+	self.on_hover:clear()
+	self.on_mouse_hover:clear()
+end
+
+
 function Hover.on_late_init(self)
 	if not self.click_zone and const.IS_STENCIL_CHECK then
 		local stencil_node = helper.get_closest_stencil_node(self.node)
diff --git a/druid/base/scroll.lua b/druid/base/scroll.lua
index 01fbdd4..796335f 100755
--- a/druid/base/scroll.lua
+++ b/druid/base/scroll.lua
@@ -174,6 +174,14 @@ function Scroll.init(self, view_node, content_node)
 end
 
 
+function Scroll.on_internal_remove(self)
+	component.on_internal_remove(self)
+	self.on_scroll:clear()
+	self.on_scroll_to:clear()
+	self.on_point_scroll:clear()
+end
+
+
 function Scroll.on_late_init(self)
 	if not self.click_zone and const.IS_STENCIL_CHECK then
 		local stencil_node = helper.get_closest_stencil_node(self.node)
diff --git a/druid/base/static_grid.lua b/druid/base/static_grid.lua
index c32d4c0..30f47ce 100644
--- a/druid/base/static_grid.lua
+++ b/druid/base/static_grid.lua
@@ -115,6 +115,16 @@ function StaticGrid.init(self, parent, element, in_row)
 end
 
 
+function StaticGrid.on_internal_remove(self)
+	component.on_internal_remove(self)
+	self.on_add_item:clear()
+	self.on_remove_item:clear()
+	self.on_change_items:clear()
+	self.on_clear:clear()
+	self.on_update_positions:clear()
+end
+
+
 local _temp_pos = vmath.vector3(0)
 --- Return pos for grid node index
 -- @tparam StaticGrid self @{StaticGrid}
diff --git a/druid/base/swipe.lua b/druid/base/swipe.lua
index d4ecc27..69e9b3a 100644
--- a/druid/base/swipe.lua
+++ b/druid/base/swipe.lua
@@ -99,6 +99,12 @@ function Swipe.init(self, node, on_swipe_callback)
 end
 
 
+function Swipe.on_internal_remove(self)
+	component.on_internal_remove(self)
+	self.on_swipe:clear()
+end
+
+
 function Swipe.on_late_init(self)
 	if not self.click_zone and const.IS_STENCIL_CHECK then
 		local stencil_node = helper.get_closest_stencil_node(self.node)
diff --git a/druid/base/text.lua b/druid/base/text.lua
index 8981ccc..13ce80d 100755
--- a/druid/base/text.lua
+++ b/druid/base/text.lua
@@ -217,6 +217,14 @@ function Text.init(self, node, value, adjust_type)
 end
 
 
+function Text.on_internal_remove(self)
+	component.on_internal_remove(self)
+	self.on_set_text:clear()
+	self.on_set_pivot:clear()
+	self.on_update_text_scale:clear()
+end
+
+
 function Text.on_layout_change(self)
 	self:set_to(self.last_value)
 end
diff --git a/druid/component.lua b/druid/component.lua
index 02d351a..6374344 100644
--- a/druid/component.lua
+++ b/druid/component.lua
@@ -8,6 +8,7 @@
 local const = require("druid.const")
 local class = require("druid.system.middleclass")
 local helper = require("druid.helper")
+local tablepool = require("druid.system.tablepool")
 
 
 local BaseComponent = class("druid.component")
@@ -348,6 +349,11 @@ function BaseComponent.set_debug(self, is_debug)
 end
 
 
+--- On remove method on druid:remove or druid:final (protected)
+function BaseComponent:on_internal_remove()
+end
+
+
 --- Return true, if input priority was changed
 -- @tparam BaseComponent self @{BaseComponent}
 -- @local
diff --git a/druid/const.lua b/druid/const.lua
index 3e8c0d9..2d23a60 100755
--- a/druid/const.lua
+++ b/druid/const.lua
@@ -7,6 +7,8 @@
 
 local M = {}
 
+M.POOL_ID = "druid_table_pool"
+
 M.ACTION_TEXT = hash(sys.get_config("druid.input_text", "text"))
 M.ACTION_TOUCH = hash(sys.get_config("druid.input_touch", "touch"))
 M.ACTION_MARKED_TEXT = hash(sys.get_config("druid.input_marked_text", "marked_text"))
diff --git a/druid/event.lua b/druid/event.lua
index e540de8..11bc2f3 100644
--- a/druid/event.lua
+++ b/druid/event.lua
@@ -5,6 +5,8 @@
 -- @alias druid.event
 
 local class = require("druid.system.middleclass")
+local const = require("druid.const")
+local tablepool = require("druid.system.tablepool")
 
 local DruidEvent = class("druid.event")
 
@@ -29,11 +31,12 @@ function DruidEvent.subscribe(self, callback, context)
 	assert(type(self) == "table", "You should subscribe to event with : syntax")
 	assert(type(callback) == "function", "Callback should be function")
 
-	self._callbacks = self._callbacks or {}
-	table.insert(self._callbacks, {
-		callback = callback,
-		context = context
-	})
+	self._callbacks = self._callbacks or tablepool.fetch(const.POOL_ID)
+	local callback_table = tablepool.fetch(const.POOL_ID, 0, 2)
+	callback_table.callback = callback
+	callback_table.context = context
+
+	table.insert(self._callbacks, callback_table)
 
 	return callback
 end
@@ -50,6 +53,7 @@ function DruidEvent.unsubscribe(self, callback, context)
 
 	for index, callback_info in ipairs(self._callbacks) do
 		if callback_info.callback == callback and callback_info.context == context then
+			tablepool.release(self._callbacks[index])
 			table.remove(self._callbacks, index)
 			return
 		end
@@ -71,6 +75,12 @@ end
 --- Clear the all event handlers
 -- @tparam DruidEvent self @{DruidEvent}
 function DruidEvent.clear(self)
+	if self._callbacks then
+		for index = #self._callbacks, 1, -1 do
+			tablepool.release(self._callbacks[index])
+		end
+	end
+	tablepool.release(self._callbacks)
 	self._callbacks = nil
 end
 
@@ -83,7 +93,7 @@ function DruidEvent.trigger(self, ...)
 		return false
 	end
 
-	for index, callback_info in ipairs(self._callbacks) do
+	for _, callback_info in ipairs(self._callbacks) do
 		if callback_info.context then
 			callback_info.callback(callback_info.context, ...)
 		else
diff --git a/druid/extended/checkbox.lua b/druid/extended/checkbox.lua
index ef1b295..f7d4c82 100755
--- a/druid/extended/checkbox.lua
+++ b/druid/extended/checkbox.lua
@@ -67,6 +67,12 @@ function Checkbox.on_layout_change(self)
 end
 
 
+function Checkbox.on_internal_remove(self)
+	component.on_internal_remove(self)
+	self.on_change_state:clear()
+end
+
+
 --- Set checkbox state
 -- @tparam Checkbox self @{Checkbox}
 -- @tparam bool state Checkbox state
diff --git a/druid/extended/checkbox_group.lua b/druid/extended/checkbox_group.lua
index 2ca9561..493e5ab 100644
--- a/druid/extended/checkbox_group.lua
+++ b/druid/extended/checkbox_group.lua
@@ -41,6 +41,13 @@ function CheckboxGroup.init(self, nodes, callback, click_nodes)
 end
 
 
+function CheckboxGroup.on_internal_remove(self)
+	component.on_internal_remove(self)
+	self.on_checkbox_click:clear()
+end
+
+
+
 --- Set checkbox group state
 -- @tparam CheckboxGroup self @{CheckboxGroup}
 -- @tparam bool[] indexes Array of checkbox state
diff --git a/druid/extended/data_list.lua b/druid/extended/data_list.lua
index e8e95c6..05f21e6 100644
--- a/druid/extended/data_list.lua
+++ b/druid/extended/data_list.lua
@@ -76,6 +76,12 @@ function DataList.on_remove(self)
 end
 
 
+function DataList.on_internal_remove(self)
+	component.on_internal_remove(self)
+	self.on_scroll_progress_change:clear()
+end
+
+
 --- Set new data set for DataList component
 -- @tparam DataList self @{DataList}
 -- @tparam table data The new data array
diff --git a/druid/extended/dynamic_grid.lua b/druid/extended/dynamic_grid.lua
index 0593715..a9da0ae 100644
--- a/druid/extended/dynamic_grid.lua
+++ b/druid/extended/dynamic_grid.lua
@@ -89,6 +89,16 @@ function DynamicGrid.init(self, parent)
 end
 
 
+function DynamicGrid.on_internal_remove(self)
+	component.on_internal_remove(self)
+	self.on_add_item:clear()
+	self.on_remove_item:clear()
+	self.on_change_items:clear()
+	self.on_clear:clear()
+	self.on_update_positions:clear()
+end
+
+
 function DynamicGrid.on_layout_change(self)
 	self:_update(true)
 end
diff --git a/druid/extended/input.lua b/druid/extended/input.lua
index d463871..d8f43b3 100755
--- a/druid/extended/input.lua
+++ b/druid/extended/input.lua
@@ -154,6 +154,17 @@ function Input.init(self, click_node, text_node, keyboard_type)
 end
 
 
+function Input.on_internal_remove(self)
+	component.on_internal_remove(self)
+	self.on_input_select:clear()
+	self.on_input_unselect:clear()
+	self.on_input_text:clear()
+	self.on_input_empty:clear()
+	self.on_input_full:clear()
+	self.on_input_wrong:clear()
+end
+
+
 function Input.on_input(self, action_id, action)
 	if self.is_selected then
 		local input_text = nil
diff --git a/druid/extended/lang_text.lua b/druid/extended/lang_text.lua
index f78b70b..fec0c7d 100755
--- a/druid/extended/lang_text.lua
+++ b/druid/extended/lang_text.lua
@@ -41,6 +41,12 @@ function LangText.init(self, node, locale_id, no_adjust)
 end
 
 
+function LangText.on_internal_remove(self)
+	component.on_internal_remove(self)
+	self.on_change:clear()
+end
+
+
 function LangText.on_language_change(self)
 	if self.last_locale then
 		self:translate(self.last_locale, unpack(self.last_locale_args))
diff --git a/druid/extended/layout.lua b/druid/extended/layout.lua
index 37963f0..719e2ae 100644
--- a/druid/extended/layout.lua
+++ b/druid/extended/layout.lua
@@ -39,6 +39,12 @@ function Layout:init(node, mode, on_size_changed_callback)
 end
 
 
+function Layout.on_internal_remove(self)
+	component.on_internal_remove(self)
+	self.on_size_changed:clear()
+end
+
+
 function Layout:on_window_resized()
     local window_x, window_y = window.get_size()
     local stretch_x = window_x / self.window_size.x
diff --git a/druid/extended/progress.lua b/druid/extended/progress.lua
index 509e57b..99ef6b2 100644
--- a/druid/extended/progress.lua
+++ b/druid/extended/progress.lua
@@ -121,6 +121,12 @@ function Progress.init(self, node, key, init_value)
 end
 
 
+function Progress.on_internal_remove(self)
+	component.on_internal_remove(self)
+	self.on_change:clear()
+end
+
+
 -- @tparam Progress self @{Progress}
 function Progress.on_late_init(self)
 	self:set_to(self._init_value)
diff --git a/druid/extended/radio_group.lua b/druid/extended/radio_group.lua
index fef1d00..768959d 100644
--- a/druid/extended/radio_group.lua
+++ b/druid/extended/radio_group.lua
@@ -50,6 +50,12 @@ function RadioGroup.init(self, nodes, callback, click_nodes)
 end
 
 
+function RadioGroup.on_internal_remove(self)
+	component.on_internal_remove(self)
+	self.on_radio_click:clear()
+end
+
+
 --- Set radio group state
 -- @tparam RadioGroup self @{RadioGroup}
 -- @tparam number index Index in radio group
diff --git a/druid/extended/slider.lua b/druid/extended/slider.lua
index 4a8c90c..ea5470b 100644
--- a/druid/extended/slider.lua
+++ b/druid/extended/slider.lua
@@ -77,6 +77,12 @@ function Slider.init(self, node, end_pos, callback)
 end
 
 
+function Slider.on_internal_remove(self)
+	component.on_internal_remove(self)
+	self.on_change_value:clear()
+end
+
+
 function Slider.on_layout_change(self)
 	self:set(self.value)
 end
diff --git a/druid/extended/timer.lua b/druid/extended/timer.lua
index 21ac56b..e31bdb7 100644
--- a/druid/extended/timer.lua
+++ b/druid/extended/timer.lua
@@ -65,6 +65,14 @@ function Timer.init(self, node, seconds_from, seconds_to, callback)
 end
 
 
+function Timer.on_internal_remove(self)
+	component.on_internal_remove(self)
+	self.on_tick:clear()
+	self.on_set_enabled:clear()
+	self.on_timer_end:clear()
+end
+
+
 function Timer.update(self, dt)
 	if not self.is_on then
 		return
diff --git a/druid/system/druid_instance.lua b/druid/system/druid_instance.lua
index e286e78..d2f2c99 100755
--- a/druid/system/druid_instance.lua
+++ b/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
diff --git a/druid/system/tablepool.lua b/druid/system/tablepool.lua
new file mode 100644
index 0000000..2c8a803
--- /dev/null
+++ b/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