MDL-62757 themes: validate theme preset files

Preset files need to be validated to ensure compiling SCSS does not break.
2019-12-04 19:12:44 +01:00
parent 800563e415
commit 8040fafaa8
5 changed files with 100 additions and 4 deletions
@@ -11092,3 +11092,95 @@ class admin_settings_sitepolicy_handler_select extends admin_setting_configselec
        return true;
    }
 }
+
+/**
+ * Used to validate theme presets code and ensuring they compile well.
+ *
+ * @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
+ * @copyright 2019 Bas Brands <bas@moodle.com>
+ */
+class admin_setting_configthemepreset extends admin_setting_configselect {
+
+    /** @var string The name of the theme to check for */
+    private $themename;
+
+    /**
+     * Constructor
+     * @param string $name unique ascii name, either 'mysetting' for settings that in config,
+     * or 'myplugin/mysetting' for ones in config_plugins.
+     * @param string $visiblename localised
+     * @param string $description long localised info
+     * @param string|int $defaultsetting
+     * @param array $choices array of $value=>$label for each selection
+     * @param string $themename name of theme to check presets for.
+     */
+    public function __construct($name, $visiblename, $description, $defaultsetting, $choices, $themename) {
+        $this->themename = $themename;
+        parent::__construct($name, $visiblename, $description, $defaultsetting, $choices);
+    }
+
+    /**
+     * Write settings if validated
+     *
+     * @param string $data
+     * @return string
+     */
+    public function write_setting($data) {
+        $validated = $this->validate($data);
+        if ($validated !== true) {
+            return $validated;
+        }
+        return ($this->config_write($this->name, $data) ? '' : get_string('errorsetting', 'admin'));
+    }
+
+    /**
+     * Validate the preset file to ensure its parsable.
+     *
+     * @param string $data The preset file chosen.
+     * @return mixed bool true for success or string:error on failure.
+     */
+    public function validate($data) {
+
+        if (in_array($data, ['default.scss', 'plain.scss'])) {
+            return true;
+        }
+
+        $fs = get_file_storage();
+        $theme = theme_config::load($this->themename);
+        $context = context_system::instance();
+
+        // If the preset has not changed there is no need to validate it.
+        if ($theme->settings->preset == $data) {
+            return true;
+        }
+
+        if ($presetfile = $fs->get_file($context->id, 'theme_' . $this->themename, 'preset', 0, '/', $data)) {
+            // This operation uses a lot of resources.
+            raise_memory_limit(MEMORY_EXTRA);
+            core_php_time_limit::raise(300);
+
+            // TODO: MDL-62757 When changing anything in this method please do not forget to check
+            // if the get_css_content_from_scss() method in class theme_config needs updating too.
+
+            $compiler = new core_scss();
+            $compiler->prepend_raw_scss($theme->get_pre_scss_code());
+            $compiler->append_raw_scss($presetfile->get_content());
+            if ($scssproperties = $theme->get_scss_property()) {
+                $compiler->setImportPaths($scssproperties[0]);
+            }
+            $compiler->append_raw_scss($theme->get_extra_scss_code());
+
+            try {
+                $compiler->to_css();
+            } catch (Exception $e) {
+                return get_string('invalidthemepreset', 'admin', $e->getMessage());
+            }
+
+            // Try to save memory.
+            $compiler = null;
+            unset($compiler);
+        }
+
+        return true;
+    }
+}