Update 'lib.php'

Synchronizing iAssign Git with the current iAssign stable version (until Moodle 5.0).
Small changes in: ilm_manager.php, lang/*/iassign.php
Bigger changes in: ilm_manager_form.php, lib.php, settings_form.php, settings.php, version.php, backup/moodle2/*.php, ilm_debug/escreva.php, ilm_handlers/java.php
New iLM versions: iassign/ilm/iFractions/, iassign/ilm/iHanoi/, iassign/ilm/iVProg/
New file (was missing): settings_activities.php

lib.php

@@ -174,7 +174,8 @@ function iassign_grade_item ($iassign) {
   $iassign->grade = 0;
   $grades = NULL;
 
-  if (array_key_exists('cmidnumber', $iassign)) { //it may not be always present
+  //RR  if (array_key_exists('cmidnumber', $iassign)) //it may not be always present
+  if (isset($iassign->cmidnumber)) { //it may not be always present
     $params = array('itemname' => $iassign->name, 'idnumber' => $iassign->cmidnumber);
     }
   else {
@@ -454,7 +455,10 @@ function restore_one_submission ($info, $restore, $iassign, $submission) {
   }
 
 
-/// Serves the data attachments. Implements needed access control ;-)
+/// Used by Moodle file system to return iLM file content
+//  It is called under URL http://.../pluginfile.php/2470/mod_iassign/exercise/903/aula5-baricentro_EF_web.geo
+//                                                   (1)  (2)         (3)      (4) (5)
+//  Where (1), (2), (3), (4) and (5) are (respctivelly) field 'contextid', 'component', 'fileare', 'itemid' and 'filename' of {files}
 //  @param object $course
 //  @param object $cm
 //  @param object $context
@@ -462,6 +466,8 @@ function restore_one_submission ($info, $restore, $iassign, $submission) {
 //  @param array $args
 //  @param bool $forcedownload
 //  @return bool false if file not found, does not return if found - justsend the file
+//  @calledby /lib/filelib.php: function file_pluginfile($relativepath, $forcedownload, $preview = null, $offline = false, $embed = false)
+//            $filefunction = $component.'_pluginfile'; if (function_exists($filefunction)) $filefunction($course, $cm, $context, $filearea, $args, $forcedownload, $sendfileoptions);
 function iassign_pluginfile ($course, $cm, $context, $filearea, $args, $forcedownload) {
   global $CFG, $DB;
 
@@ -472,18 +478,41 @@ function iassign_pluginfile ($course, $cm, $context, $filearea, $args, $forcedow
     return false;
     }
 
-
   $fs = get_file_storage();
-  $postid = (int) array_shift($args);
+  $itemid = (int) array_shift($args); // must be {files}.itemid
   $relativepath = implode('/', $args);
-  $fullpath = "/$context->id/mod_iassign/$filearea/$postid/$relativepath";
-
-  if (!$file = $fs->get_file_by_hash(sha1($fullpath)) or $file->is_directory()) {
-    return false;
+  $fullpath = "/" . $context->id . "/mod_iassign/" . $filearea . "/" . $itemid . "/" . $relativepath;
+
+  //D echo "lib.php: iassign_pluginfile(.): context.id=" . $context->id . ": fullpath=" . $fullpath . "<br/>\n"; //exit;
+  //D echo "sha1(" . $fullpath . ")=". sha1($fullpath) . "<br/>";
+  //lib.php: iassign_pluginfile(.): context.id=55853: fullpath=/55853/mod_iassign/exercise/6023/ex4_7_laco_simples_for_imprimir_n_primeiros_termos_pa.ivph
+  //                                                            (1)   (2)         (3)      (4)  (5)
+  // They are {files}'s fields: (1)=contextid ; (2)=component ; (3)=filearea ; (4)=itemid ; (5)=filename
+
+  // ./lib/filestorage/file_storage.php: public function get_file_by_hash($pathnamehash)
+  // Try to recover iLM content file through {files}.pathnamehash
+  $one_file = $fs->get_file_by_hash(sha1($fullpath));
+  if (!$one_file || $one_file->is_directory()) { // if different Moodle version created iAssign {files}...
+    //D echo "Erro: via sha1 falhou!<br/>\n";
+    // ./lib/filestorage/file_storage.php: public function get_area_files($contextid, $component, $filearea, $itemid = false,...)
+    $array_files = $fs->get_area_files($context->id, "mod_iassign", $filearea, $itemid);
+    foreach ($array_files as $one_file) {
+      $filename = $one_file->get_filename();
+      if ($filename!=".")
+        break; // found the {iassign_statement} associated {files}
+      //D echo "{files} : id=" . $one_file->get_id() . ", filename=" . $one_file->get_filename() . "<br/>\n";
+      }
+    if (!$one_file || $one_file->filename == ".") {
+      //D echo "Ops! Not found...<br/>"; exit;
+      return false;
+      }
     }
 
-  // finally send the file
-  send_stored_file($file, 0, 0, false); // download MUST be forced - security!
+  //D echo "one_file: id=" . $one_file->get_id() . ", filename=" . $one_file->get_filename() . "<br/>"; //exit;
+
+  // If error "Object of class stored_file could not be converted to string" => lost reference
+  // Finally send the file
+  send_stored_file($one_file, 0, 0, false); // download MUST be forced - security!
 
   return false;
   }