Added a field extension for SQLite and let the database sort the elements by the given ID order directly

config/packages/doctrine.yaml

@@ -38,6 +38,7 @@ doctrine:
             string_functions:
                 regexp: DoctrineExtensions\Query\Mysql\Regexp
                 ifnull: DoctrineExtensions\Query\Mysql\IfNull
+                field: DoctrineExtensions\Query\Mysql\Field
 
 when@test:
     doctrine:

src/Doctrine/SQLiteRegexExtension.php

@@ -47,14 +47,48 @@ class SQLiteRegexExtension
 
             //Ensure that the function really exists on the connection, as it is marked as experimental according to PHP documentation
             if($native_connection instanceof \PDO && method_exists($native_connection, 'sqliteCreateFunction' )) {
-                $native_connection->sqliteCreateFunction('REGEXP', function ($pattern, $value) {
+                $native_connection->sqliteCreateFunction('REGEXP', $this->regexp(...), 2);
+                $native_connection->sqliteCreateFunction('FIELD', $this->field(...));
+            }
+        }
+    }
+
+    /**
+     * This function emulates the MySQL regexp function for SQLite
+     * @param  string  $pattern
+     * @param  string  $value
+     * @return int
+     */
+    private function regexp(string $pattern, string $value): int
+    {
         try {
             return (mb_ereg($pattern, $value)) ? 1 : 0;
         } catch (\ErrorException $e) {
             throw InvalidRegexException::fromMBRegexError($e);
         }
-                });
-            }
-        }
+    }
+
+    /**
+     * This function emulates the MySQL field function for SQLite
+     * This function returns the index (position) of the first argument in the subsequent arguments.#
+     * If the first argument is not found or is NULL, 0 is returned.
+     * @param  string|int|null  $value
+     * @param  mixed  ...$array
+     * @return int
+     */
+    private function field(string|int|null $value, ...$array): int
+    {
+        if ($value === null) {
+            return 0;
+        }
+
+        //We are loose with the types here
+        $index = array_search($value, $array, false);
+
+        if ($index === false) {
+            return 0;
+        }
+
+        return $index + 1;
     }
 }

src/Repository/AttachmentContainingDBElementRepository.php

@@ -56,13 +56,14 @@ class AttachmentContainingDBElementRepository extends NamedDBElementRepository
         $qb = $this->createQueryBuilder('element');
         $q = $qb->select('element')
             ->where('element.id IN (?1)')
+            //Order the results in the same order as the IDs in the input array (mysql supports this native, for SQLite we emulate it)
+            ->orderBy('FIELD(element.id, ?1)')
             ->setParameter(1, $ids)
             ->getQuery();
 
         $q->setFetchMode($this->getEntityName(), 'master_picture_attachment', ClassMetadataInfo::FETCH_EAGER);
 
         $result = $q->getResult();
-        $this->sortResultArrayByIDArray($result, $ids);
 
         //Cache the result
         $this->elementsAndPreviewAttachmentCache[$cache_key] = $result;

src/Repository/DBElementRepository.php

@@ -113,13 +113,12 @@ class DBElementRepository extends EntityRepository
         $q = $qb->select('element')
             ->where('element.id IN (?1)')
             ->setParameter(1, $ids)
+            //Order the results in the same order as the IDs in the input array (mysql supports this native, for SQLite we emulate it)
+            ->orderBy('FIELD(element.id, ?1)')
             ->getQuery();
 
         $result = $q->getResult();
 
-        //Sort the result so that the elements are in the same order as the input array
-        $this->sortResultArrayByIDArray($result, $ids);
-
         //Cache the result
         $this->find_elements_by_id_cache[$cache_key] = $result;