Improve resource load cache

-Added a new method in Resource: reset_state , used for reloading the same resource from disk
-Added a new cache mode "replace" in ResourceLoader, which reuses existing loaded sub-resources but resets their data from disk (or replaces them if they chaged type)
-Because the correct sub-resource paths are always loaded now, this fixes bugs with subresource folding or subresource ordering when saving.

8 files changed, 26 insertions, 18 deletions

diff --git a/editor/editor_audio_buses.cpp b/editor/editor_audio_buses.cpp
index 2eef4636d6..69a13957e6 100644
--- a/editor/editor_audio_buses.cpp
+++ b/editor/editor_audio_buses.cpp
@@ -1193,7 +1193,7 @@ void EditorAudioBuses::_load_layout() {
 void EditorAudioBuses::_load_default_layout() {
 	String layout_path = ProjectSettings::get_singleton()->get("audio/default_bus_layout");
 
-	Ref<AudioBusLayout> state = ResourceLoader::load(layout_path, "", true);
+	Ref<AudioBusLayout> state = ResourceLoader::load(layout_path, "", ResourceFormatLoader::CACHE_MODE_IGNORE);
 	if (state.is_null()) {
 		EditorNode::get_singleton()->show_warning(vformat(TTR("There is no '%s' file."), layout_path));
 		return;
@@ -1209,7 +1209,7 @@ void EditorAudioBuses::_load_default_layout() {
 
 void EditorAudioBuses::_file_dialog_callback(const String &p_string) {
 	if (file_dialog->get_file_mode() == EditorFileDialog::FILE_MODE_OPEN_FILE) {
-		Ref<AudioBusLayout> state = ResourceLoader::load(p_string, "", true);
+		Ref<AudioBusLayout> state = ResourceLoader::load(p_string, "", ResourceFormatLoader::CACHE_MODE_IGNORE);
 		if (state.is_null()) {
 			EditorNode::get_singleton()->show_warning(TTR("Invalid file, not an audio bus layout."));
 			return;
@@ -1330,7 +1330,7 @@ EditorAudioBuses::EditorAudioBuses() {
 void EditorAudioBuses::open_layout(const String &p_path) {
 	EditorNode::get_singleton()->make_bottom_panel_item_visible(this);
 
-	Ref<AudioBusLayout> state = ResourceLoader::load(p_path, "", true);
+	Ref<AudioBusLayout> state = ResourceLoader::load(p_path, "", ResourceFormatLoader::CACHE_MODE_IGNORE);
 	if (state.is_null()) {
 		EditorNode::get_singleton()->show_warning(TTR("Invalid file, not an audio bus layout."));
 		return;
diff --git a/editor/editor_folding.cpp b/editor/editor_folding.cpp
index 9f98795e16..97a2c67c26 100644
--- a/editor/editor_folding.cpp
+++ b/editor/editor_folding.cpp
@@ -259,13 +259,17 @@ void EditorFolding::_do_object_unfolds(Object *p_object, Set<RES> &resources) {
 					}
 				}
 			}
-		}
 
-		if (E->get().type == Variant::OBJECT) {
-			RES res = p_object->get(E->get().name);
-			if (res.is_valid() && !resources.has(res) && res->get_path() != String() && !res->get_path().is_resource_file()) {
-				resources.insert(res);
-				_do_object_unfolds(res.ptr(), resources);
+			if (E->get().type == Variant::OBJECT) {
+				RES res = p_object->get(E->get().name);
+				print_line("res: " + String(E->get().name) + " valid " + itos(res.is_valid()));
+				if (res.is_valid()) {
+					print_line("path " + res->get_path());
+				}
+				if (res.is_valid() && !resources.has(res) && res->get_path() != String() && !res->get_path().is_resource_file()) {
+					resources.insert(res);
+					_do_object_unfolds(res.ptr(), resources);
+				}
 			}
 		}
 	}
diff --git a/editor/editor_node.cpp b/editor/editor_node.cpp
index e7291b014f..dd39a08d1f 100644
--- a/editor/editor_node.cpp
+++ b/editor/editor_node.cpp
@@ -1003,7 +1003,7 @@ Error EditorNode::load_resource(const String &p_resource, bool p_ignore_broken_d
 	dependency_errors.clear();
 
 	Error err;
-	RES res = ResourceLoader::load(p_resource, "", false, &err);
+	RES res = ResourceLoader::load(p_resource, "", ResourceFormatLoader::CACHE_MODE_REUSE, &err);
 	ERR_FAIL_COND_V(!res.is_valid(), ERR_CANT_OPEN);
 
 	if (!p_ignore_broken_deps && dependency_errors.has(p_resource)) {
@@ -3452,7 +3452,7 @@ Error EditorNode::load_scene(const String &p_scene, bool p_ignore_broken_deps, b
 	dependency_errors.clear();
 
 	Error err;
-	Ref<PackedScene> sdata = ResourceLoader::load(lpath, "", true, &err);
+	Ref<PackedScene> sdata = ResourceLoader::load(lpath, "", ResourceFormatLoader::CACHE_MODE_REPLACE, &err);
 	if (!sdata.is_valid()) {
 		_dialog_display_load_error(lpath, err);
 		opening_prev = false;
@@ -5274,6 +5274,8 @@ void EditorNode::_file_access_close_error_notify(const String &p_str) {
 }
 
 void EditorNode::reload_scene(const String &p_path) {
+	/*
+	 * No longer necesary since scenes now reset and reload their internal resource if needed.
 	//first of all, reload internal textures, materials, meshes, etc. as they might have changed on disk
 
 	List<Ref<Resource>> cached;
@@ -5291,6 +5293,8 @@ void EditorNode::reload_scene(const String &p_path) {
 		to_clear.pop_front();
 	}
 
+	*/
+
 	int scene_idx = -1;
 	for (int i = 0; i < editor_data.get_edited_scene_count(); i++) {
 		if (editor_data.get_scene_path(i) == p_path) {
diff --git a/editor/import/resource_importer_scene.cpp b/editor/import/resource_importer_scene.cpp
index 9944712931..d0e5798045 100644
--- a/editor/import/resource_importer_scene.cpp
+++ b/editor/import/resource_importer_scene.cpp
@@ -964,7 +964,7 @@ void ResourceImporterScene::_make_external_resources(Node *p_node, const String
 
 					if (FileAccess::exists(ext_name) && p_keep_animations) {
 						// Copy custom animation tracks from previously imported files.
-						Ref<Animation> old_anim = ResourceLoader::load(ext_name, "Animation", true);
+						Ref<Animation> old_anim = ResourceLoader::load(ext_name, "Animation", ResourceFormatLoader::CACHE_MODE_IGNORE);
 						if (old_anim.is_valid()) {
 							for (int i = 0; i < old_anim->get_track_count(); i++) {
 								if (!old_anim->track_is_imported(i)) {
@@ -1004,7 +1004,7 @@ void ResourceImporterScene::_make_external_resources(Node *p_node, const String
 						p_materials[mat] = ResourceLoader::load(ext_name);
 					} else {
 						ResourceSaver::save(ext_name, mat, ResourceSaver::FLAG_CHANGE_PATH);
-						p_materials[mat] = ResourceLoader::load(ext_name, "", true); // disable loading from the cache.
+						p_materials[mat] = ResourceLoader::load(ext_name, "", ResourceFormatLoader::CACHE_MODE_IGNORE); // disable loading from the cache.
 					}
 				}
 
@@ -1061,7 +1061,7 @@ void ResourceImporterScene::_make_external_resources(Node *p_node, const String
 										p_materials[mat] = ResourceLoader::load(ext_name);
 									} else {
 										ResourceSaver::save(ext_name, mat, ResourceSaver::FLAG_CHANGE_PATH);
-										p_materials[mat] = ResourceLoader::load(ext_name, "", true); // disable loading from the cache.
+										p_materials[mat] = ResourceLoader::load(ext_name, "", ResourceFormatLoader::CACHE_MODE_IGNORE); // disable loading from the cache.
 									}
 								}
 
diff --git a/editor/plugins/packed_scene_translation_parser_plugin.cpp b/editor/plugins/packed_scene_translation_parser_plugin.cpp
index 1f20a87565..0a949c8610 100644
--- a/editor/plugins/packed_scene_translation_parser_plugin.cpp
+++ b/editor/plugins/packed_scene_translation_parser_plugin.cpp
@@ -42,7 +42,7 @@ Error PackedSceneEditorTranslationParserPlugin::parse_file(const String &p_path,
 	// These properties are translated with the tr() function in the C++ code when being set or updated.
 
 	Error err;
-	RES loaded_res = ResourceLoader::load(p_path, "PackedScene", false, &err);
+	RES loaded_res = ResourceLoader::load(p_path, "PackedScene", ResourceFormatLoader::CACHE_MODE_REUSE, &err);
 	if (err) {
 		ERR_PRINT("Failed to load " + p_path);
 		return err;
diff --git a/editor/plugins/script_editor_plugin.cpp b/editor/plugins/script_editor_plugin.cpp
index 216c0c3bef..a6afd45686 100644
--- a/editor/plugins/script_editor_plugin.cpp
+++ b/editor/plugins/script_editor_plugin.cpp
@@ -894,7 +894,7 @@ void ScriptEditor::_reload_scripts() {
 
 		Ref<Script> script = edited_res;
 		if (script != nullptr) {
-			Ref<Script> rel_script = ResourceLoader::load(script->get_path(), script->get_class(), true);
+			Ref<Script> rel_script = ResourceLoader::load(script->get_path(), script->get_class(), ResourceFormatLoader::CACHE_MODE_IGNORE);
 			ERR_CONTINUE(!rel_script.is_valid());
 			script->set_source_code(rel_script->get_source_code());
 			script->set_last_modified_time(rel_script->get_last_modified_time());
diff --git a/editor/plugins/script_text_editor.cpp b/editor/plugins/script_text_editor.cpp
index f57c8fbd6b..71b18497b0 100644
--- a/editor/plugins/script_text_editor.cpp
+++ b/editor/plugins/script_text_editor.cpp
@@ -688,7 +688,7 @@ void ScriptEditor::_update_modified_scripts_for_external_editor(Ref<Script> p_fo
 		uint64_t date = FileAccess::get_modified_time(script->get_path());
 
 		if (last_date != date) {
-			Ref<Script> rel_script = ResourceLoader::load(script->get_path(), script->get_class(), true);
+			Ref<Script> rel_script = ResourceLoader::load(script->get_path(), script->get_class(), ResourceFormatLoader::CACHE_MODE_IGNORE);
 			ERR_CONTINUE(!rel_script.is_valid());
 			script->set_source_code(rel_script->get_source_code());
 			script->set_last_modified_time(rel_script->get_last_modified_time());
diff --git a/editor/plugins/shader_editor_plugin.cpp b/editor/plugins/shader_editor_plugin.cpp
index 05a1561f7d..8be82628cb 100644
--- a/editor/plugins/shader_editor_plugin.cpp
+++ b/editor/plugins/shader_editor_plugin.cpp
@@ -405,7 +405,7 @@ void ShaderEditor::_check_for_external_edit() {
 }
 
 void ShaderEditor::_reload_shader_from_disk() {
-	Ref<Shader> rel_shader = ResourceLoader::load(shader->get_path(), shader->get_class(), true);
+	Ref<Shader> rel_shader = ResourceLoader::load(shader->get_path(), shader->get_class(), ResourceFormatLoader::CACHE_MODE_IGNORE);
 	ERR_FAIL_COND(!rel_shader.is_valid());
 
 	shader->set_code(rel_shader->get_code());