MDL-64658 files: Support constant to avoid file merging

... in file_save_draft_area_files

lib/filelib.php

@@ -29,6 +29,12 @@ defined('MOODLE_INTERNAL') || die();
  */
 define('BYTESERVING_BOUNDARY', 's1k2o3d4a5k6s7');
 
+
+/**
+ * Do not process file merging when working with draft area files.
+ */
+define('IGNORE_FILE_MERGE', -1);
+
 /**
  * Unlimited area size constant
  */
@@ -888,6 +894,7 @@ function file_remove_editor_orphaned_files($editor) {
  *
  * @category files
  * @param int $draftitemid the id of the primary draft area.
+ *            When set to -1 (probably, by a WebService) it won't process file merging, keeping the original state of the file area.
  * @param int $usercontextid the user's context id.
  * @param string $text some html content that needs to have files copied to the correct draft area.
  * @param bool $forcehttps force https urls.
@@ -899,6 +906,11 @@ function file_merge_draft_areas($draftitemid, $usercontextid, $text, $forcehttps
         return null;
     }
 
+    // Do not merge files, leave it as it was.
+    if ($draftitemid === IGNORE_FILE_MERGE) {
+        return null;
+    }
+
     $urls = extract_draft_file_urls_from_text($text, $forcehttps, $usercontextid, 'user', 'draft');
 
     // No draft areas to rewrite.
@@ -1015,6 +1027,7 @@ function file_copy_file_to_file_area($file, $filename, $itemid) {
  * @global stdClass $USER
  * @param int $draftitemid the id of the draft area to use. Normally obtained
  *      from file_get_submitted_draft_itemid('elementname') or similar.
+ *      When set to -1 (probably, by a WebService) it won't process file merging, keeping the original state of the file area.
  * @param int $contextid This parameter and the next two identify the file area to save to.
  * @param string $component
  * @param string $filearea indentifies the file area.
@@ -1028,6 +1041,11 @@ function file_copy_file_to_file_area($file, $filename, $itemid) {
 function file_save_draft_area_files($draftitemid, $contextid, $component, $filearea, $itemid, array $options=null, $text=null, $forcehttps=false) {
     global $USER;
 
+    // Do not merge files, leave it as it was.
+    if ($draftitemid === IGNORE_FILE_MERGE) {
+        return null;
+    }
+
     $usercontext = context_user::instance($USER->id);
     $fs = get_file_storage();
 

lib/tests/filelib_test.php

@@ -807,6 +807,70 @@ class core_filelib_testcase extends advanced_testcase {
         $this->assertEquals($filecontent, $fileref->get_content());
     }
 
+    /**
+     * Test avoid file merging when working with draft areas.
+     */
+    public function test_ignore_file_merging_in_draft_area() {
+        global $USER, $DB;
+
+        $this->resetAfterTest(true);
+
+        $generator = $this->getDataGenerator();
+        $user = $generator->create_user();
+        $usercontext = context_user::instance($user->id);
+        $USER = $DB->get_record('user', array('id' => $user->id));
+
+        $repositorypluginname = 'user';
+
+        $args = array();
+        $args['type'] = $repositorypluginname;
+        $repos = repository::get_instances($args);
+        $userrepository = reset($repos);
+        $this->assertInstanceOf('repository', $userrepository);
+
+        $fs = get_file_storage();
+        $syscontext = context_system::instance();
+
+        $filecontent = 'User file content';
+
+        // Create a user private file.
+        $userfilerecord = new stdClass;
+        $userfilerecord->contextid = $usercontext->id;
+        $userfilerecord->component = 'user';
+        $userfilerecord->filearea  = 'private';
+        $userfilerecord->itemid    = 0;
+        $userfilerecord->filepath  = '/';
+        $userfilerecord->filename  = 'userfile.txt';
+        $userfilerecord->source    = 'test';
+        $userfile = $fs->create_file_from_string($userfilerecord, $filecontent);
+        $userfileref = $fs->pack_reference($userfilerecord);
+        $contenthash = $userfile->get_contenthash();
+
+        $filerecord = array(
+            'contextid' => $syscontext->id,
+            'component' => 'core',
+            'filearea'  => 'phpunit',
+            'itemid'    => 0,
+            'filepath'  => '/',
+            'filename'  => 'test.txt',
+        );
+        // Create a file reference.
+        $fileref = $fs->create_file_from_reference($filerecord, $userrepository->id, $userfileref);
+        $this->assertCount(2, $fs->get_area_files($usercontext->id, 'user', 'private'));    // 2 because includes the '.' file.
+
+        // Save using empty draft item id, all files will be deleted.
+        file_save_draft_area_files(0, $usercontext->id, 'user', 'private', 0);
+        $this->assertCount(0, $fs->get_area_files($usercontext->id, 'user', 'private'));
+
+        // Create a file again.
+        $userfile = $fs->create_file_from_string($userfilerecord, $filecontent);
+        $this->assertCount(2, $fs->get_area_files($usercontext->id, 'user', 'private'));
+
+        // Save without merge.
+        file_save_draft_area_files(IGNORE_FILE_MERGE, $usercontext->id, 'user', 'private', 0);
+        $this->assertCount(2, $fs->get_area_files($usercontext->id, 'user', 'private'));
+    }
+
     /**
      * Tests the strip_double_headers function in the curl class.
      */

lib/upgrade.txt

@@ -22,6 +22,8 @@ attribute on forms to avoid collisions in forms loaded in AJAX requests.
 * Behat timeout constants behat_base::TIMEOUT, EXTENDED_TIMEOUT, and REDUCED_TIMEOUT have been
   deprecated. Please instead use the functions behat_base::get_timeout(), get_extended_timeout(),
   and get_reduced_timeout(). These allow for timeouts to be increased by a setting in config.php.
+* The $draftitemid parameter of file_save_draft_area_files() function now supports the constant IGNORE_FILE_MERGE:
+  When the parameter is set to that constant, the function won't process file merging, keeping the original state of the file area.
 
 === 3.6 ===