MDL-35434 add support for theme setting files

This patch is based on work by Gareth J Barnard, Pau Ferrer Ocaña (crazyserver) and others.

lib/outputlib.php

@@ -43,7 +43,7 @@ require_once($CFG->libdir.'/outputrequirementslib.php');
  * this function.
  */
 function theme_reset_all_caches() {
-    global $CFG;
+    global $CFG, $PAGE;
     require_once("$CFG->libdir/filelib.php");
 
     $next = time();
@@ -56,6 +56,10 @@ function theme_reset_all_caches() {
 
     set_config('themerev', $next); // time is unique even when you reset/switch database
     fulldelete("$CFG->cachedir/theme");
+
+    if ($PAGE) {
+        $PAGE->reload_theme();
+    }
 }
 
 /**
@@ -1074,6 +1078,74 @@ class theme_config {
         return $url;
     }
 
+    /**
+     * Returns URL to the stored file via pluginfile.php.
+     *
+     * Note the theme must also implement pluginfile.php handler,
+     * theme revision is used instead of the itemid.
+     *
+     * @param string $setting
+     * @param string $filearea
+     * @return string protocol relative URL or null if not present
+     */
+    public function setting_file_url($setting, $filearea) {
+        global $CFG;
+
+        if (empty($this->settings->$setting)) {
+            return null;
+        }
+
+        $component = 'theme_'.$this->name;
+        $itemid = theme_get_revision();
+        $filepath = $this->settings->$setting;
+        $syscontext = context_system::instance();
+
+        $url = moodle_url::make_file_url("$CFG->wwwroot/pluginfile.php", "/$syscontext->id/$component/$filearea/$itemid".$filepath);
+
+        // Now this is tricky because the we can not hardcode http or https here, lets use the relative link.
+        // Note: unfortunately moodle_url does not support //urls yet.
+
+        $url = preg_replace('|^https?://|i', '//', $url->out(false));
+
+        return $url;
+    }
+
+    /**
+     * Serve the theme setting file.
+     *
+     * @param string $filearea
+     * @param array $args
+     * @param bool $forcedownload
+     * @param array $options
+     * @return bool may terminate if file not found or donotdie not specified
+     */
+    public function setting_file_serve($filearea, $args, $forcedownload, $options) {
+        global $CFG;
+        require_once("$CFG->libdir/filelib.php");
+
+        $syscontext = context_system::instance();
+        $component = 'theme_'.$this->name;
+
+        $revision = array_shift($args);
+        if ($revision < 0) {
+            $lifetime = 0;
+        } else {
+            $lifetime = 60*60*24*60;
+        }
+
+        $fs = get_file_storage();
+        $relativepath = implode('/', $args);
+
+        $fullpath = "/{$syscontext->id}/{$component}/{$filearea}/0/{$relativepath}";
+        $fullpath = rtrim($fullpath, '/');
+        if ($file = $fs->get_file_by_hash(sha1($fullpath))) {
+            send_stored_file($file, $lifetime, 0, $forcedownload, $options);
+            return true;
+        } else {
+            send_file_not_found();
+        }
+    }
+
     /**
      * Resolves the real image location.
      *

lib/pagelib.php

@@ -1296,6 +1296,18 @@ class moodle_page {
         $this->_theme = theme_config::load($themename);
     }
 
+    /**
+     * Reload theme settings.
+     *
+     * This is used when we need to reset settings
+     * because they are now double cached in theme.
+     */
+    public function reload_theme() {
+        if (!is_null($this->_theme)) {
+            $this->_theme = theme_config::load($this->_theme->name);
+        }
+    }
+
     /**
      * This function indicates that current page requires the https
      * when $CFG->loginhttps enabled.