From a0d5133f108085e9923d051d5fd85d311a5989eb Mon Sep 17 00:00:00 2001
From: Paul Holden <paulh@moodle.com>
Date: Tue, 7 May 2024 17:14:26 +0100
Subject: [PATCH] MDL-81781 dataformat: public helper method to get writer
 instance.

---
 .upgradenotes/MDL-81781-2024060309073788.yml |  7 +++++
 lib/classes/dataformat.php                   |  9 +++---
 lib/tablelib.php                             |  7 ++---
 lib/tests/dataformat_test.php                | 32 +++++++++++++-------
 4 files changed, 35 insertions(+), 20 deletions(-)
 create mode 100644 .upgradenotes/MDL-81781-2024060309073788.yml

diff --git a/.upgradenotes/MDL-81781-2024060309073788.yml b/.upgradenotes/MDL-81781-2024060309073788.yml
new file mode 100644
index 00000000000..dd76955e05a
--- /dev/null
+++ b/.upgradenotes/MDL-81781-2024060309073788.yml
@@ -0,0 +1,7 @@
+issueNumber: MDL-81781
+notes:
+  core:
+    - message: >
+        The `\core\dataformat::get_format_instance` method is now public, and
+        can be used to retrieve a writer instance for a given dataformat
+      type: changed
diff --git a/lib/classes/dataformat.php b/lib/classes/dataformat.php
index 70bdcec5a6b..99b92e70428 100644
--- a/lib/classes/dataformat.php
+++ b/lib/classes/dataformat.php
@@ -25,6 +25,7 @@
 namespace core;
 
 use coding_exception;
+use core\dataformat\base;
 use core_php_time_limit;
 use stored_file;
 
@@ -41,15 +42,15 @@ class dataformat {
      * Return an instance of a dataformat writer from given dataformat type
      *
      * @param string $dataformat
-     * @return dataformat\base
-     * @throws coding_exception
+     * @return base
+     *
+     * @throws coding_exception For unknown dataformat
      */
-    protected static function get_format_instance(string $dataformat): \core\dataformat\base {
+    public static function get_format_instance(string $dataformat): base {
         $classname = 'dataformat_' . $dataformat . '\writer';
         if (!class_exists($classname)) {
             throw new coding_exception('Invalid dataformat', $dataformat);
         }
-
         return new $classname();
     }
 
diff --git a/lib/tablelib.php b/lib/tablelib.php
index 463ac019897..4954b4fd802 100644
--- a/lib/tablelib.php
+++ b/lib/tablelib.php
@@ -51,6 +51,7 @@ define('TABLE_P_BOTTOM', 2);
  */
 define('TABLE_SHOW_ALL_PAGE_SIZE', 5000);
 
+use core\dataformat;
 use core_table\local\filter\filterset;
 
 /**
@@ -2315,11 +2316,7 @@ class table_dataformat_export_format extends table_default_export_format_parent
             throw new coding_exception("Output can not be buffered before instantiating table_dataformat_export_format");
         }
 
-        $classname = 'dataformat_' . $dataformat . '\writer';
-        if (!class_exists($classname)) {
-            throw new coding_exception("Unable to locate dataformat/$dataformat/classes/writer.php");
-        }
-        $this->dataformat = new $classname;
+        $this->dataformat = dataformat::get_format_instance($dataformat);
 
         // The dataformat export time to first byte could take a while to generate...
         set_time_limit(0);
diff --git a/lib/tests/dataformat_test.php b/lib/tests/dataformat_test.php
index ebd10b0910a..27dc12ef4da 100644
--- a/lib/tests/dataformat_test.php
+++ b/lib/tests/dataformat_test.php
@@ -14,35 +14,45 @@
 // You should have received a copy of the GNU General Public License
 // along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
 
-/**
- * Tests for the dataformat plugins
- *
- * @package    core
- * @copyright  2020 Paul Holden <paulh@moodle.com>
- * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
- */
-
 namespace core;
 
+use coding_exception;
 use context_system;
 use core_component;
 
 /**
- * Dataformat tests
+ * Tests for the dataformat plugins
  *
  * @package    core
  * @covers     \core\dataformat
  * @copyright  2020 Paul Holden <paulh@moodle.com>
  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  */
-class dataformat_test extends \advanced_testcase {
+final class dataformat_test extends \advanced_testcase {
+
+    /**
+     * Test getting writer instance for given dataformat
+     */
+    public function test_get_format_instance(): void {
+        $instance = dataformat::get_format_instance('pdf');
+        $this->assertInstanceOf(\dataformat_pdf\writer::class, $instance);
+    }
+
+    /**
+     * Test getting writer instance for invalid dataformat
+     */
+    public function test_get_format_instance_invalid(): void {
+        $this->expectException(coding_exception::class);
+        $this->expectExceptionMessage('Invalid dataformat (weird)');
+        dataformat::get_format_instance('weird');
+    }
 
     /**
      * Data provider to return array of dataformat types
      *
      * @return array
      */
-    public function write_data_provider(): array {
+    public static function write_data_provider(): array {
         $data = [];
 
         $dataformats = core_component::get_plugin_list('dataformat');