MDL-71981 dataformat: indicate HTML support in writer callback.

dataformat/upgrade.txt

@@ -1,6 +1,13 @@
 This files describes API changes in /dataformat/ download system,
 information provided here is intended especially for developers.
 
+=== 3.11.1 ===
+* Optional $callback for the following \core\dataformat methods now receive a second argument to define
+  whether the current format writer supports HTML:
+  - download_data()
+  - write_data()
+  - write_data_to_filearea()
+
 === 3.9 ===
 * The following methods have been added to the base dataformat class to allow instances to export to a local
   file. They can be overridden in extending classes to define how files should be created:

lib/classes/dataformat.php

@@ -60,7 +60,8 @@ protected static function get_format_instance(string $dataformat): \core\datafor
      * @param string $dataformat
      * @param array $columns
      * @param Iterable $iterator
-     * @param callable|null $callback
+     * @param callable|null $callback Optional callback method to apply to each record prior to writing, which accepts two
+     *      parameters as such: function($record, bool $supportshtml) returning formatted record
      * @throws coding_exception
      */
     public static function download_data(string $filename, string $dataformat, array $columns, Iterable $iterator,
@@ -90,7 +91,7 @@ public static function download_data(string $filename, string $dataformat, array
         $rownum = 0;
         foreach ($iterator as $row) {
             if (is_callable($callback)) {
-                $row = $callback($row);
+                $row = $callback($row, $format->supports_html());
             }
             if ($row === null) {
                 continue;
@@ -132,7 +133,7 @@ public static function write_data(string $filename, string $dataformat, array $c
         $rownum = 0;
         foreach ($iterator as $row) {
             if (is_callable($callback)) {
-                $row = $callback($row);
+                $row = $callback($row, $format->supports_html());
             }
             if ($row === null) {
                 continue;