Patch package.searchers with functions using the patched searchpath

Author: gilzoide

SConstruct

@@ -13,9 +13,11 @@ env.Command(
     [
         "src/generated/global_enums.hpp",
         "src/generated/utility_functions.hpp",
+        "src/generated/package_searcher.h",
     ],
     [
         "src/generate_code.py",
+        "src/luaopen/package_searcher.lua",
         "lib/godot-cpp/gdextension/extension_api.json",
         "lib/godot-cpp/gen/include/godot_cpp/variant/utility_functions.hpp",
     ],

src/generate_code.py

@@ -4,6 +4,7 @@
 SRC_DIR = os.path.dirname(__file__)
 DEST_DIR = os.path.join(SRC_DIR, "generated")
 API_JSON_PATH = os.path.join(SRC_DIR, "..", "lib", "godot-cpp", "gdextension", "extension_api.json")
+PACKAGE_SEARCHER_SRC = os.path.join(SRC_DIR, "luaopen", "package_searcher.lua")
 PRIMITIVE_VARIANTS = [
     "bool",
     "int",
@@ -18,7 +19,8 @@
 
 def generate_utility_functions(utility_functions):
     lines = [
-        "#undef register_utility_functions\n#define register_utility_functions(state)"
+        "// This file was automatically generated by generate_code.py",
+        "#undef register_utility_functions\n#define register_utility_functions(state)",
     ]
     for f in utility_functions:
         name = f["name"]
@@ -39,7 +41,8 @@ def generate_utility_functions(utility_functions):
 
 def generate_enums(global_enums):
     lines = [
-        "#undef register_global_enums\n#define register_global_enums(state)"
+        "// This file was automatically generated by generate_code.py",
+        "#undef register_global_enums\n#define register_global_enums(state)",
     ]
     for enum in global_enums:
         lines.append(f"\t/* {enum['name']} */")
@@ -48,6 +51,19 @@ def generate_enums(global_enums):
     return " \\\n".join(lines) + "\n"
 
 
+def generate_package_searcher():
+    lines = [
+        "// This file was automatically generated by generate_code.py",
+        "const char package_searcher_lua[] = ",
+    ]
+    with open(PACKAGE_SEARCHER_SRC, "r") as f:
+        for line in f:
+            line = line.replace("\\", "\\\\").replace('"', '\\"').rstrip("\r\n")
+            lines.append('"' + line + '\\n"')
+    lines.append(";")
+    return "\n".join(lines)
+
+
 def main():
     with open(API_JSON_PATH) as f:
         api = json.load(f)
@@ -60,6 +76,10 @@ def main():
     with open(os.path.join(DEST_DIR, "global_enums.hpp"), "w") as f:
         code = generate_enums(api["global_enums"])
         f.write(code)
+    
+    with open(os.path.join(DEST_DIR, "package_searcher.h"), "w") as f:
+        code = generate_package_searcher()
+        f.write(code)
 
 
 if __name__ == "__main__":

src/luaopen/local_paths.cpp

@@ -31,18 +31,27 @@
 #include <godot_cpp/classes/os.hpp>
 #include <godot_cpp/classes/project_settings.hpp>
 
+#include "../generated/package_searcher.h"
+
 using namespace luagdextension;
 
-static int searchpath(lua_State *L, const String& name, const String& path, const String& sep, const String& rep) {
-	String template_name = sep.is_empty() ? name : name.replace(sep, rep);
+static int l_searchpath(lua_State *L) {
+	String name = luaL_checkstring(L, 1);
+	String path = luaL_checkstring(L, 2);
+	String sep = luaL_optstring(L, 3, ".");
+	String rep = luaL_optstring(L, 4, "/");
+	if (!sep.is_empty()) {
+		name = name.replace(sep, rep);
+	}
+
 	String execdir_repl = Engine::get_singleton()->is_editor_hint()
 		? ProjectSettings::get_singleton()->globalize_path("res://")
 		: OS::get_singleton()->get_executable_path().get_base_dir();
 
 	PackedStringArray path_list = path.split(";", false);
 	PackedStringArray not_found_list;
 	for (const String& path_template : path_list) {
-		String filename = path_template.replace("?", template_name).replace("!", execdir_repl);
+		String filename = path_template.replace("?", name).replace("!", execdir_repl);
 		if (FileAccess::file_exists(filename)) {
 			sol::stack::push(L, filename);
 			return 1;
@@ -62,10 +71,6 @@ static int searchpath(lua_State *L, const String& name, const String& path, cons
 	return 2;
 }
 
-static int l_searchpath(lua_State *L) {
-	return searchpath(L, luaL_checkstring(L, 1), luaL_checkstring(L, 2), luaL_optstring(L, 3, "."), luaL_optstring(L, 4, "/"));
-}
-
 static int l_loadfile(lua_State *L) {
 	sol::state_view state(L);
 	String filename = luaL_optstring(L, 1, "");
@@ -107,6 +112,7 @@ extern "C" int luaopen_godot_local_paths(lua_State *L) {
 
 	if (auto package = state.get<sol::optional<sol::table>>("package")) {
 		(*package)["searchpath"] = l_searchpath;
+		state.do_string(package_searcher_lua);
 	}
 
 	state["loadfile"] = l_loadfile;

src/luaopen/package_searcher.lua

@@ -0,0 +1,42 @@
+local loadlib, searchpath = package.loadlib, package.searchpath
+
+local function lua_searcher(name)
+	local filename, err = searchpath(name, package.path)
+	if filename then
+		return assert(loadfile(filename))
+	else
+		return err
+	end
+end
+
+local function c_searcher(name, name_override)
+	local filename, err = searchpath(name, package.cpath)
+	if not filename then
+		return err
+	end
+
+	local func_suffix = (name_override or name):replace(".", "_")
+	-- Split module name if a "-" is found
+	local igmark = func_suffix:find("-", 1, false)
+	if igmark then
+		local funcname = "luaopen_" .. func_suffix:sub(1, igmark - 1)
+		local f = loadlib(filename, funcname)
+		if f then return f end
+		func_suffix = func_suffix:sub(igmark + 1)
+	end
+	local f, err = loadlib(filename, "luaopen_" .. func_suffix)
+	return assert(f, ("error loading module %q from file %q:\n\t%s"):format(name_override or name, filename, err))
+end
+
+local function c_root_searcher(name)
+	local root_name = name:match("^([^.]+)%.")
+	if not root_name then
+		return nil
+	end
+	return c_searcher(root_name, name)
+end
+
+local searchers = package.searchers or package.loaders
+searchers[2] = lua_searcher
+searchers[3] = c_searcher
+searchers[4] = c_root_searcher