MDL-51306 mod_folder: Use context_module to find details

renderable should not be used for extracting
details. Use cm to get context and dir information

mod/folder/download_folder.php

@@ -35,8 +35,7 @@
 
 $folder = $DB->get_record('folder', array('id' => $cm->instance), '*', MUST_EXIST);
 
-$foldertree = new folder_tree($folder, $cm);
-$downloadable = folder_archive_available($folder, $foldertree);
+$downloadable = folder_archive_available($folder, $cm);
 if (!$downloadable) {
     print_error('cannotdownloaddir', 'repository');
 }

mod/folder/lib.php

@@ -486,16 +486,20 @@ function folder_view($folder, $course, $cm, $context) {
 /**
  * Check if the folder can be zipped and downloaded.
  * @param stdClass $folder
- * @param folder_tree $foldertree
+ * @param context_module $cm
  * @return bool True if the folder can be zipped and downloaded.
  * @throws \dml_exception
  */
-function folder_archive_available($folder, $foldertree) {
+function folder_archive_available($folder, $cm) {
     if (!$folder->showdownloadfolder) {
         return false;
     }
 
-    $size = folder_get_directory_size($foldertree->dir);
+    $context = context_module::instance($cm->id);
+    $fs = get_file_storage();
+    $dir = $fs->get_area_tree($context->id, 'mod_folder', 'content', 0);
+
+    $size = folder_get_directory_size($dir);
     $maxsize = get_config('folder', 'maxsizetodownload') * 1024 * 1024;
 
     if ($size == 0) {

mod/folder/renderer.php

@@ -67,7 +67,7 @@ public function display_folder(stdClass $folder) {
         // Do not append the edit button on the course page.
         if ($folder->display != FOLDER_DISPLAY_INLINE) {
             $containercontents = '';
-            $downloadable = folder_archive_available($folder, $foldertree);
+            $downloadable = folder_archive_available($folder, $cm);
 
             if ($downloadable) {
                 $containercontents .= $this->output->single_button(