utils.js

const Gio = imports.gi.Gio;
const Config = imports.misc.config;
const ExtensionUtils = imports.misc.extensionUtils;

/**
 * getSettings:
 * @schema: (optional): the GSettings schema id
 *
 * Builds and return a GSettings schema for @schema, using schema files
 * in extensionsdir/schemas. If @schema is not provided, it is taken from
 * metadata['settings-schema'].
 */
function getSettings(schema) {
    let extension = ExtensionUtils.getCurrentExtension();

    schema = schema || extension.metadata['settings-schema'];

    const GioSSS = Gio.SettingsSchemaSource;

    // check if this extension was built with "make zip-file", and thus
    // has the schema files in a subfolder
    // otherwise assume that extension has been installed in the
    // same prefix as gnome-shell (and therefore schemas are available
    // in the standard folders)
    let schemaDir = extension.dir.get_child('schemas');
    let schemaSource;
    if (schemaDir.query_exists(null))
        schemaSource = GioSSS.new_from_directory(schemaDir.get_path(),
                                                 GioSSS.get_default(),
                                                 false);
    else
        schemaSource = GioSSS.get_default();

    let schemaObj = schemaSource.lookup(schema, true);
    if (!schemaObj)
        throw new Error('Schema ' + schema + ' could not be found for extension ' +
                        extension.metadata.uuid + '. Please check your installation.');

    return new Gio.Settings({ settings_schema: schemaObj });
}