Add export plugin that minifies Lua scripts on release

Author: gilzoide

CHANGELOG.md

@@ -1,5 +1,10 @@
 # Changelog
 ## [Unreleased]
+### Added
+- `EditorExportPlugin` for minifying Lua scripts with `LuaSrcDiet` on
+  release exports. Minification may be turned off with the
+  `Lua PluginScript/Export/Minify On Release Export` project setting.
+
 ### Changed
 - Release builds' init Lua script are minified with `LuaSrcDiet` and libraries
   are now `strip`ed, resulting in smaller dynamic libraries

README.md

@@ -43,17 +43,20 @@ In the `Project -> Project Settings...` window, some settings are available:
 - **Lua PluginScript/Package Path/Behavior**: Whether templates will replace
   [package.path](https://www.lua.org/manual/5.1/manual.html#pdf-package.path),
   be appended to it or prepended to it.
-  Default behavior: replace.
+  Default behavior: `replace`.
 - **Lua PluginScript/Package Path/Templates**: String array of templates to be
   injected into `package.path`.
   Default templates: `res://?.lua` and `res://?/init.lua`.
 - **Lua PluginScript/Package C Path/Behavior**: Whether templates will replace
   [package.cpath](https://www.lua.org/manual/5.1/manual.html#pdf-package.cpath),
   be appended to it or prepended to it.
-  Default behavior: replace.
+  Default behavior: `replace`.
 - **Lua PluginScript/Package C Path/Templates**: String array of templates to be
   injected into `package.cpath`.
   Default templates: `!/?.dll` and `!/loadall.dll` on Windows, `!/?.so` and `!/loadall.so` elsewhere.
+- **Lua PluginScript/Export/Minify On Release Export**: Whether Lua scritps
+  should be minified on release exports.
+  Defaults to `true`.
 
 Also, an editor plugin is included, currently with a barebones REPL for Lua
 expressions, located in the bottom panel of the editor.
@@ -196,7 +199,7 @@ return MyClass
 - [X] API documentation
 - [ ] Unit tests
 - [ ] Example projects
-- [ ] Export plugin to minify Lua scripts
+- [X] Export plugin to minify Lua scripts
 - [X] Drop-in binary release in GitHub
 - [X] Submit to Asset Library
 

plugin/export_plugin.lua

@@ -0,0 +1,73 @@
+-- @file plugin/export_plugin.lua  EditorExportPlugin for minifying Lua scripts on release exports
+-- This file is part of Godot Lua PluginScript: https://github.com/gilzoide/godot-lua-pluginscript
+--
+-- Copyright (C) 2021 Gil Barbosa Reis.
+-- 
+-- Permission is hereby granted, free of charge, to any person obtaining a copy
+-- of this software and associated documentation files (the “Software”), to
+-- deal in the Software without restriction, including without limitation the
+-- rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+-- sell copies of the Software, and to permit persons to whom the Software is
+-- furnished to do so, subject to the following conditions:
+-- 
+-- The above copyright notice and this permission notice shall be included in
+-- all copies or substantial portions of the Software.
+-- 
+-- THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+-- IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+-- FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+-- AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+-- LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+-- FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+-- IN THE SOFTWARE.
+local package_path = package.path
+package.path = 'res://addons/godot-lua-pluginscript/plugin/?.lua;res://addons/godot-lua-pluginscript/plugin/?/init.lua;' .. package_path
+local luasrcdiet = require 'luasrcdiet'
+package.path = package_path
+
+local LuaExportPlugin = {
+	is_tool = true,
+	extends = 'EditorExportPlugin',
+}
+
+local SHOULD_MINIFY_RELEASE_SETTING = 'lua_pluginscript/export/minify_on_release_export'
+
+local function add_project_setting(name, initial_value)
+	if not ProjectSettings:has_setting(name) then
+		ProjectSettings:set_setting(name, initial_value)
+	end
+	ProjectSettings:set_initial_value(name, initial_value)
+end
+add_project_setting(SHOULD_MINIFY_RELEASE_SETTING, true)
+
+function LuaExportPlugin:_export_begin(features, is_debug, path, flags)
+	self.ignore_path = self:get_script().resource_path:get_base_dir()
+	self.should_minify = not is_debug and ProjectSettings:get_setting(SHOULD_MINIFY_RELEASE_SETTING)
+	self.file = File:new()
+end
+
+function LuaExportPlugin:_export_file(path, type, features)
+	if path:begins_with(self.ignore_path) then
+		self:skip()
+	elseif self.should_minify and path:ends_with('.lua') then
+		if self.file:open(path, File.READ) == GD.OK then
+			local source = tostring(self.file:get_as_text())
+			self.file:close()
+			local optsource = luasrcdiet.optimize(luasrcdiet.MAXIMUM_OPTS, source)
+			print(string.format('[LuaPluginScript] Minified %s: %s -> %s (%d%% reduction)',
+				path,
+				String.humanize_size(#source),
+				String.humanize_size(#optsource),
+				100 - math.floor(#optsource / #source * 100))
+			)
+			self:add_file(path, PoolByteArray.from(optsource), false)
+		end
+	end
+end
+
+function LuaExportPlugin:_export_end()
+	self.ignore_path = nil
+	self.file = nil
+end
+
+return LuaExportPlugin

plugin/plugin.gd

@@ -24,14 +24,22 @@ tool
 extends EditorPlugin
 
 var _lua_repl
+var _lua_export_plugin
 
 func _enter_tree() -> void:
 	_lua_repl = preload("lua_repl.tscn").instance()
-	var repl_button = add_control_to_bottom_panel(_lua_repl, "Lua REPL")
+	add_control_to_bottom_panel(_lua_repl, "Lua REPL")
+
+	_lua_export_plugin = preload("export_plugin.lua").new()
+	add_export_plugin(_lua_export_plugin)
 
 
 func _exit_tree() -> void:
 	if _lua_repl:
 		remove_control_from_bottom_panel(_lua_repl)
 		_lua_repl.free()
 		_lua_repl = null
+	if _lua_export_plugin:
+		remove_export_plugin(_lua_export_plugin)
+		_lua_export_plugin.unreference()
+		_lua_export_plugin = null