MDL-83986 file: Add replace file methods to file_storage.

Author: micaherne

.upgradenotes/MDL-83986-2024121102442582.yml

@@ -0,0 +1,11 @@
+issueNumber: MDL-83986
+notes:
+  core_files:
+    - message: >
+        The file_storage class now has two methods to enable updating the
+        content of a file:
+
+        - `replace_file_from_file()`
+
+        - `replace_file_from_string()`
+      type: improved

public/lib/filestorage/file_storage.php

@@ -2467,6 +2467,60 @@ public function update_references($referencefileid, $lastsync, $lifetime, $conte
         $DB->update_record('files_reference', (object)$data);
     }
 
+    /**
+     * Replace the content of an existing file with that from a given real file.
+     *
+     * @param stored_file $file The file to replace
+     * @param string $filepath The path to the file on disk
+     *
+     * @return stored_file The new file
+     *
+     * @throws moodle_exception
+     */
+    public function replace_file_from_file(stored_file $file, string $filepath): stored_file {
+        global $DB;
+
+        $tx = $DB->start_delegated_transaction();
+        try {
+            $filerecord = $DB->get_record('files', ['id' => $file->get_id()], '*', MUST_EXIST);
+            $file->delete();
+            $newfile = $this->create_file_from_pathname($filerecord, $filepath);
+        } catch (file_exception $e) {
+            $tx->rollback($e);
+        }
+
+        $tx->allow_commit();
+
+        return $newfile;
+    }
+
+    /**
+     * Replace the content of an existing file with a given string.
+     *
+     * @param stored_file $file The file to replace
+     * @param string $content The new content
+     *
+     * @return stored_file The new file
+     *
+     * @throws moodle_exception
+     */
+    public function replace_file_from_string(stored_file $file, string $content): stored_file {
+        global $DB;
+
+        $tx = $DB->start_delegated_transaction();
+        try {
+            $filerecord = $DB->get_record('files', ['id' => $file->get_id()], '*', MUST_EXIST);
+            $file->delete();
+            $newfile = $this->create_file_from_string($filerecord, $content);
+        } catch (file_exception $e) {
+            $tx->rollback($e);
+        }
+
+        $tx->allow_commit();
+
+        return $newfile;
+    }
+
     /**
      * Calculate and return the contenthash of the supplied file.
      *

public/lib/filestorage/tests/file_storage_test.php

@@ -2367,6 +2367,46 @@ public function test_before_file_created_hook_executed_filecontent(): void {
             $file->get_contenthash(),
         );
     }
+
+    /**
+     * Tests the replace_file_from_file method.
+     *
+     * @covers \file_storage::replace_file_from_file
+     *
+     * @return void
+     */
+    public function test_replace_file_from_file() {
+        $this->resetAfterTest(true);
+        $fs = get_file_storage();
+
+        $record = $this->generate_file_record();
+
+        $file1 = $fs->create_file_from_string($record, 'text contents');
+        $newfile1 = $fs->replace_file_from_file($file1, __DIR__ . '/fixtures/test.txt');
+
+        $this->assertEquals('test', $newfile1->get_content());
+        $this->assertEquals($file1->get_timecreated(), $newfile1->get_timecreated());
+    }
+
+    /**
+     * Tests the replace_file_from_string method.
+     *
+     * @covers \file_storage::replace_file_from_string
+     *
+     * @return void
+     */
+    public function test_replace_file_from_string() {
+        $this->resetAfterTest(true);
+        $fs = get_file_storage();
+
+        $record = $this->generate_file_record();
+
+        $file1 = $fs->create_file_from_string($record, 'text contents');
+        $newfile1 = $fs->replace_file_from_string($file1, 'new text contents');
+
+        $this->assertEquals('new text contents', $newfile1->get_content());
+        $this->assertEquals($file1->get_timecreated(), $newfile1->get_timecreated());
+    }
 }
 
 class test_stored_file_inspection extends stored_file {