[CSM] Don't load the IO library. (#6087)

* [CSM] Don't load the IO library.

* Rename the function to match the Lua API function name and add a missing `const`

* Add a comment to explain some strange code and fix the other issues pointed out by shadowninja.

src/script/cpp_api/s_async.cpp

@@ -198,6 +198,7 @@ void AsyncEngine::prepareEnvironment(lua_State* L, int top)
 AsyncWorkerThread::AsyncWorkerThread(AsyncEngine* jobDispatcher,
 		const std::string &name) :
 	Thread(name),
+	ScriptApiBase(ScriptingType::Async),
 	jobDispatcher(jobDispatcher)
 {
 	lua_State *L = getStack();

src/script/cpp_api/s_base.cpp

@@ -71,7 +71,8 @@ class ModNameStorer
 	ScriptApiBase
 */
 
-ScriptApiBase::ScriptApiBase()
+ScriptApiBase::ScriptApiBase(ScriptingType type):
+		m_type(type)
 {
 #ifdef SCRIPTAPI_LOCK_DEBUG
 	m_lock_recursion_count = 0;
@@ -82,7 +83,10 @@ ScriptApiBase::ScriptApiBase()
 
 	lua_atpanic(m_luastack, &luaPanic);
 
-	luaL_openlibs(m_luastack);
+	if (m_type == ScriptingType::Client)
+		clientOpenLibs(m_luastack);
+	else
+		luaL_openlibs(m_luastack);
 
 	// Make the ScriptApiBase* accessible to ModApiBase
 	lua_pushlightuserdata(m_luastack, this);
@@ -106,7 +110,10 @@ ScriptApiBase::ScriptApiBase()
 	lua_newtable(m_luastack);
 	lua_setglobal(m_luastack, "core");
 
-	lua_pushstring(m_luastack, DIR_DELIM);
+	if (m_type == ScriptingType::Client)
+		lua_pushstring(m_luastack, "/");
+	else
+		lua_pushstring(m_luastack, DIR_DELIM);
 	lua_setglobal(m_luastack, "DIR_DELIM");
 
 	lua_pushstring(m_luastack, porting::getPlatformName());
@@ -128,6 +135,28 @@ int ScriptApiBase::luaPanic(lua_State *L)
 	return 0;
 }
 
+void ScriptApiBase::clientOpenLibs(lua_State *L)
+{
+	static const std::vector<std::pair<std::string, lua_CFunction>> m_libs = {
+		{ "", luaopen_base },
+		{ LUA_LOADLIBNAME, luaopen_package },
+		{ LUA_TABLIBNAME,  luaopen_table   },
+		{ LUA_OSLIBNAME,   luaopen_os      },
+		{ LUA_STRLIBNAME,  luaopen_string  },
+		{ LUA_MATHLIBNAME, luaopen_math    },
+		{ LUA_DBLIBNAME,   luaopen_debug   },
+#if USE_LUAJIT
+		{ LUA_JITLIBNAME,  luaopen_jit     },
+#endif
+	};
+
+	for (const std::pair<std::string, lua_CFunction> &lib : m_libs) {
+	    lua_pushcfunction(L, lib.second);
+	    lua_pushstring(L, lib.first.c_str());
+	    lua_call(L, 1, 0);
+	}
+}
+
 void ScriptApiBase::loadMod(const std::string &script_path,
 		const std::string &mod_name)
 {

src/script/cpp_api/s_base.h

@@ -23,15 +23,19 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include <string>
 #include <thread>
 #include <mutex>
+#include <unordered_map>
 #include "util/basic_macros.h"
 
 extern "C" {
 #include <lua.h>
+#include <lualib.h>
 }
 
 #include "irrlichttypes.h"
 #include "common/c_types.h"
 #include "common/c_internal.h"
+#include "debug.h"
+#include "cmake_config.h"
 
 #define SCRIPTAPI_LOCK_DEBUG
 #define SCRIPTAPI_DEBUG
@@ -54,9 +58,10 @@ extern "C" {
 	setOriginFromTableRaw(index, __FUNCTION__)
 
 enum class ScriptingType: u8 {
+	Async,
 	Client,
-	Server,
-	MainMenu
+	MainMenu,
+	Server
 };
 
 class Server;
@@ -70,7 +75,12 @@ class ServerActiveObject;
 
 class ScriptApiBase {
 public:
-	ScriptApiBase();
+	ScriptApiBase(ScriptingType type);
+	// fake constructor to allow script API classes (e.g ScriptApiEnv) to virtually inherit from this one.
+	ScriptApiBase()
+	{
+		FATAL_ERROR("ScriptApiBase created without ScriptingType!");
+	}
 	virtual ~ScriptApiBase();
 	DISABLE_CLASS_COPY(ScriptApiBase);
 
@@ -91,7 +101,6 @@ class ScriptApiBase {
 
 	IGameDef *getGameDef() { return m_gamedef; }
 	Server* getServer();
-	void setType(ScriptingType type) { m_type = type; }
 	ScriptingType getType() { return m_type; }
 #ifndef SERVER
 	Client* getClient();
@@ -101,6 +110,8 @@ class ScriptApiBase {
 	void setOriginDirect(const char *origin);
 	void setOriginFromTableRaw(int index, const char *fxn);
 
+	void clientOpenLibs(lua_State *L);
+
 protected:
 	friend class LuaABM;
 	friend class LuaLBM;

src/script/scripting_client.cpp

@@ -33,10 +33,10 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "lua_api/l_localplayer.h"
 #include "lua_api/l_camera.h"
 
-ClientScripting::ClientScripting(Client *client)
+ClientScripting::ClientScripting(Client *client):
+	ScriptApiBase(ScriptingType::Client)
 {
 	setGameDef(client);
-	setType(ScriptingType::Client);
 
 	SCRIPTAPI_PRECHECKHEADER
 
@@ -59,9 +59,6 @@ ClientScripting::ClientScripting(Client *client)
 	lua_pushstring(L, "client");
 	lua_setglobal(L, "INIT");
 
-	lua_pushstring(L, "/");
-	lua_setglobal(L, "DIR_DELIM");
-
 	infostream << "SCRIPTAPI: Initialized client game modules" << std::endl;
 }
 

src/script/scripting_mainmenu.cpp

@@ -34,10 +34,10 @@ extern "C" {
 #define MAINMENU_NUM_ASYNC_THREADS 4
 
 
-MainMenuScripting::MainMenuScripting(GUIEngine* guiengine)
+MainMenuScripting::MainMenuScripting(GUIEngine* guiengine):
+		ScriptApiBase(ScriptingType::MainMenu)
 {
 	setGuiEngine(guiengine);
-	setType(ScriptingType::MainMenu);
 
 	SCRIPTAPI_PRECHECKHEADER
 

src/script/scripting_server.cpp

@@ -48,10 +48,10 @@ extern "C" {
 #include "lualib.h"
 }
 
-ServerScripting::ServerScripting(Server* server)
+ServerScripting::ServerScripting(Server* server):
+		ScriptApiBase(ScriptingType::Server)
 {
 	setGameDef(server);
-	setType(ScriptingType::Server);
 
 	// setEnv(env) is called by ScriptApiEnv::initializeEnvironment()
 	// once the environment has been created