Add initial support for the XDG Base Directory spec

Spec version 0.7 from https://standards.freedesktop.org/basedir-spec/basedir-spec-0.7.html
(latest as of this commit).

Three virtual methods are added to OS for the various XDG paths we will use:
- OS::get_data_path gives XDG_DATA_HOME, or if missing:
  ~/.local/share on X11, ~/Library/Application Support/ on macOS and %APPDATA% on Windows
- OS::get_config_path gives XDG_CONFIG_HOME, or if missing:
  ~/.config on X11, ~/Library/Application Support/ on macOS and %APPDATA% on Windows
- OS::get_cache_path gives XDG_CACHE_HOME, or if missing:
  ~/.cache on X11, ~/Library/Caches on macOS and %APPDATA% on Windows

So for Windows there are no changes, for Linux we follow the full split spec
and for macOS stuff will move from ~/.godot to ~/Library/Application Support/Godot.

Support for system-wide installation of templates on Unix was removed for now,
as it's a bit hackish and I don't think anyone uses it.

user:// will still be OS::get_data_path() + "/godot/app_userdata/$name" by
default, but when using the application/config/use_shared_user_dir option
it will now use XDG_DATA_HOME/$name, e.g. ~/.local/share/MyGame.

For now everything still goes in EditorSettings::get_settings_dir(), but
this will be changed in a later commit to make use of the new splitting
where relevant.

Part of #3513.

3 files changed, 131 insertions, 54 deletions

diff --git a/editor/editor_export.cpp b/editor/editor_export.cpp
index 3d0b09c726..6b94580813 100644
--- a/editor/editor_export.cpp
+++ b/editor/editor_export.cpp
@@ -336,33 +336,18 @@ Error EditorExportPlatform::_save_zip_file(void *p_userdata, const String &p_pat
 
 String EditorExportPlatform::find_export_template(String template_file_name, String *err) const {
 
-	String base_name = itos(VERSION_MAJOR) + "." + itos(VERSION_MINOR) + "-" + _MKSTR(VERSION_STATUS) + "/" + template_file_name;
-	String user_file = EditorSettings::get_singleton()->get_settings_dir() + "/templates/" + base_name;
-	String system_file = OS::get_singleton()->get_installed_templates_path();
-	bool has_system_path = (system_file != "");
-	system_file = system_file.plus_file(base_name);
-
-	// Prefer user file
-	if (FileAccess::exists(user_file)) {
-		return user_file;
-	}
+	String current_version = itos(VERSION_MAJOR) + "." + itos(VERSION_MINOR) + "-" + _MKSTR(VERSION_STATUS) + VERSION_MODULE_CONFIG;
+	String template_path = EditorSettings::get_singleton()->get_templates_dir().plus_file(current_version).plus_file(template_file_name);
 
-	// Now check system file
-	if (has_system_path) {
-		if (FileAccess::exists(system_file)) {
-			return system_file;
-		}
+	if (FileAccess::exists(template_path)) {
+		return template_path;
 	}
 
 	// Not found
 	if (err) {
-		*err += "No export template found at \"" + user_file + "\"";
-		if (has_system_path)
-			*err += "\n or \"" + system_file + "\".";
-		else
-			*err += ".";
+		*err += "No export template found at \"" + template_path + "\".";
 	}
-	return String(); // not found
+	return String();
 }
 
 bool EditorExportPlatform::exists_export_template(String template_file_name, String *err) const {
diff --git a/editor/editor_settings.cpp b/editor/editor_settings.cpp
index b73e7ae4cc..4673600923 100644
--- a/editor/editor_settings.cpp
+++ b/editor/editor_settings.cpp
@@ -640,8 +640,13 @@ void EditorSettings::create() {
 
 	DirAccess *dir = NULL;
 
+	String data_path;
+	String data_dir;
 	String config_path;
 	String config_dir;
+	String cache_path;
+	String cache_dir;
+
 	Ref<ConfigFile> extra_config = memnew(ConfigFile);
 
 	String exe_path = OS::get_singleton()->get_executable_path().get_base_dir();
@@ -658,28 +663,74 @@ void EditorSettings::create() {
 	memdelete(d);
 
 	if (self_contained) {
-		// editor is self contained
+
+		// editor is self contained, all in same folder
+		data_path = exe_path;
+		data_dir = data_path.plus_file("editor_data");
 		config_path = exe_path;
-		config_dir = "editor_data";
+		config_dir = data_dir;
+		cache_path = exe_path;
+		cache_dir = data_dir.plus_file("cache");
 	} else {
 
-		if (OS::get_singleton()->has_environment("APPDATA")) {
-			// Most likely under windows, save here
-			config_path = OS::get_singleton()->get_environment("APPDATA");
-			config_dir = String(_MKSTR(VERSION_SHORT_NAME)).capitalize();
-		} else if (OS::get_singleton()->has_environment("HOME")) {
-
-			config_path = OS::get_singleton()->get_environment("HOME");
-			config_dir = "." + String(_MKSTR(VERSION_SHORT_NAME)).to_lower();
+		// Typically XDG_DATA_HOME or %APPDATA%
+		data_path = OS::get_singleton()->get_data_path();
+		data_dir = data_path.plus_file(OS::get_singleton()->get_godot_dir_name());
+		// Can be different from data_path e.g. on Linux or macOS
+		config_path = OS::get_singleton()->get_config_path();
+		config_dir = config_path.plus_file(OS::get_singleton()->get_godot_dir_name());
+		// Can be different from above paths, otherwise a subfolder of data_dir
+		cache_path = OS::get_singleton()->get_cache_path();
+		if (cache_path == data_path) {
+			cache_dir = data_dir.plus_file("cache");
+		} else {
+			cache_dir = cache_path.plus_file(OS::get_singleton()->get_godot_dir_name());
 		}
-	};
+	}
 
 	ClassDB::register_class<EditorSettings>(); //otherwise it can't be unserialized
+
 	String config_file_path;
 
-	if (config_path != "") {
+	if (data_path != "" && config_path != "" && cache_path != "") {
+
+		// Validate/create data dir and subdirectories
 
 		dir = DirAccess::create(DirAccess::ACCESS_FILESYSTEM);
+		if (dir->change_dir(data_path) != OK) {
+			ERR_PRINT("Cannot find path for data directory!");
+			memdelete(dir);
+			goto fail;
+		}
+
+		if (dir->change_dir(data_dir) != OK) {
+			dir->make_dir(data_dir);
+			if (dir->change_dir(data_dir) != OK) {
+				ERR_PRINT("Cannot create data directory!");
+				memdelete(dir);
+				goto fail;
+			}
+		}
+
+		// Validate/create cache dir
+
+		if (dir->change_dir(cache_path) != OK) {
+			ERR_PRINT("Cannot find path for cache directory!");
+			memdelete(dir);
+			goto fail;
+		}
+
+		if (dir->change_dir(cache_dir) != OK) {
+			dir->make_dir(cache_dir);
+			if (dir->change_dir(cache_dir) != OK) {
+				ERR_PRINT("Cannot create cache directory!");
+				memdelete(dir);
+				goto fail;
+			}
+		}
+
+		// Validate/create config dir and subdirectories
+
 		if (dir->change_dir(config_path) != OK) {
 			ERR_PRINT("Cannot find path for config directory!");
 			memdelete(dir);
@@ -695,10 +746,17 @@ void EditorSettings::create() {
 			}
 		}
 
+		// FIXME: Move to data dir
 		if (dir->change_dir("templates") != OK) {
 			dir->make_dir("templates");
 		} else {
+			dir->change_dir("..");
+		}
 
+		// FIXME: Move to cache dir
+		if (dir->change_dir("tmp") != OK) {
+			dir->make_dir("tmp");
+		} else {
 			dir->change_dir("..");
 		}
 
@@ -715,42 +773,33 @@ void EditorSettings::create() {
 		}
 		_create_script_templates(dir->get_current_dir() + "/script_templates");
 
-		if (dir->change_dir("tmp") != OK) {
-			dir->make_dir("tmp");
-		} else {
-
-			dir->change_dir("..");
-		}
-
+		// FIXME: Rename to "projects"
 		if (dir->change_dir("config") != OK) {
 			dir->make_dir("config");
 		} else {
-
 			dir->change_dir("..");
 		}
 
-		dir->change_dir("config");
+		// Validate/create project-specific config dir
 
+		dir->change_dir("config");
 		String project_config_dir = ProjectSettings::get_singleton()->get_resource_path();
 		if (project_config_dir.ends_with("/"))
 			project_config_dir = config_path.substr(0, project_config_dir.size() - 1);
 		project_config_dir = project_config_dir.get_file() + "-" + project_config_dir.md5_text();
 
-		if (dir->change_dir(project_config_dir)) {
+		if (dir->change_dir(project_config_dir) != OK) {
 			dir->make_dir(project_config_dir);
 		} else {
 			dir->change_dir("..");
 		}
-
 		dir->change_dir("..");
 
-		// path at least is validated, so validate config file
-
-		String config_file_name = "editor_settings-" + String(_MKSTR(VERSION_MAJOR)) + ".tres";
-		config_file_path = config_path + "/" + config_dir + "/" + config_file_name;
+		// Validate editor config file
 
+		String config_file_name = "editor_settings.tres";
+		config_file_path = config_dir.plus_file(config_file_name);
 		if (!dir->file_exists(config_file_name)) {
-
 			goto fail;
 		}
 
@@ -766,7 +815,9 @@ void EditorSettings::create() {
 		singleton->save_changed_setting = true;
 		singleton->config_file_path = config_file_path;
 		singleton->project_config_dir = project_config_dir;
-		singleton->settings_dir = config_path + "/" + config_dir;
+		singleton->settings_dir = config_dir;
+		singleton->data_dir = data_dir;
+		singleton->cache_dir = cache_dir;
 
 		if (OS::get_singleton()->is_stdout_verbose()) {
 
@@ -796,7 +847,9 @@ fail:
 	singleton = Ref<EditorSettings>(memnew(EditorSettings));
 	singleton->save_changed_setting = true;
 	singleton->config_file_path = config_file_path;
-	singleton->settings_dir = config_path + "/" + config_dir;
+	singleton->settings_dir = config_dir;
+	singleton->data_dir = data_dir;
+	singleton->cache_dir = cache_dir;
 	singleton->_load_defaults(extra_config);
 	singleton->setup_language();
 	singleton->setup_network();
@@ -966,7 +1019,19 @@ void EditorSettings::add_property_hint(const PropertyInfo &p_hint) {
 	hints[p_hint.name] = p_hint;
 }
 
-// Settings paths and saved metadata
+// Data directories
+
+String EditorSettings::get_data_dir() const {
+
+	return data_dir;
+}
+
+String EditorSettings::get_templates_dir() const {
+
+	return get_data_dir().plus_file("templates");
+}
+
+// Config directories
 
 String EditorSettings::get_settings_dir() const {
 
@@ -975,9 +1040,29 @@ String EditorSettings::get_settings_dir() const {
 
 String EditorSettings::get_project_settings_dir() const {
 
+	// FIXME: Rename to "projects"
 	return get_settings_dir().plus_file("config").plus_file(project_config_dir);
 }
 
+String EditorSettings::get_text_editor_themes_dir() const {
+
+	return get_settings_dir().plus_file("text_editor_themes");
+}
+
+String EditorSettings::get_script_templates_dir() const {
+
+	return get_settings_dir().plus_file("script_templates");
+}
+
+// Cache directory
+
+String EditorSettings::get_cache_dir() const {
+
+	return cache_dir;
+}
+
+// Metadata
+
 void EditorSettings::set_project_metadata(const String &p_section, const String &p_key, Variant p_data) {
 	Ref<ConfigFile> cf = memnew(ConfigFile);
 	String path = get_project_settings_dir().plus_file("project_metadata.cfg");
diff --git a/editor/editor_settings.h b/editor/editor_settings.h
index 9db7487645..e402f70492 100644
--- a/editor/editor_settings.h
+++ b/editor/editor_settings.h
@@ -93,9 +93,11 @@ private:
 	Map<String, Ref<ShortCut> > shortcuts;
 
 	String resource_path;
+	String settings_dir;
+	String data_dir;
+	String cache_dir;
 	String config_file_path;
-	String settings_path;
-	String project_config_path;
+	String project_config_dir;
 
 	Vector<String> favorite_dirs;
 	Vector<String> recent_dirs;
@@ -147,8 +149,13 @@ public:
 	void set_resource_clipboard(const Ref<Resource> &p_resource) { clipboard = p_resource; }
 	Ref<Resource> get_resource_clipboard() const { return clipboard; }
 
+	String get_data_dir() const;
+	String get_templates_dir() const;
 	String get_settings_dir() const;
 	String get_project_settings_dir() const;
+	String get_text_editor_themes_dir() const;
+	String get_script_templates_dir() const;
+	String get_cache_dir() const;
 
 	void set_project_metadata(const String &p_section, const String &p_key, Variant p_data);
 	Variant get_project_metadata(const String &p_section, const String &p_key, Variant p_default);