MDL-68342 files: Add a faster xsendfile method to avoid db lookups

lib/filelib.php

@@ -2169,7 +2169,7 @@ function readfile_accel($file, $mimetype, $accelerate) {
         if (is_object($file)) {
             $fs = get_file_storage();
             if ($fs->supports_xsendfile()) {
-                if ($fs->xsendfile($file->get_contenthash())) {
+                if ($fs->xsendfile_file($file)) {
                     return;
                 }
             }

lib/filestorage/file_storage.php

@@ -1821,6 +1821,21 @@ class file_storage {
         }
     }
 
+    /**
+     * Serve file content using X-Sendfile header.
+     * Please make sure that all headers are already sent and the all
+     * access control checks passed.
+     *
+     * This alternate method to xsendfile() allows an alternate file system
+     * to use the full file metadata and avoid extra lookups.
+     *
+     * @param stored_file $file The file to send
+     * @return bool success
+     */
+    public function xsendfile_file(stored_file $file): bool {
+        return $this->filesystem->xsendfile_file($file);
+    }
+
     /**
      * Serve file content using X-Sendfile header.
      * Please make sure that all headers are already sent

lib/filestorage/file_system.php

@@ -435,6 +435,21 @@ abstract class file_system {
         return $image;
     }
 
+    /**
+     * Serve file content using X-Sendfile header.
+     * Please make sure that all headers are already sent and the all
+     * access control checks passed.
+     *
+     * This alternate method to xsendfile() allows an alternate file system
+     * to use the full file metadata and avoid extra lookups.
+     *
+     * @param stored_file $file The file to send
+     * @return bool success
+     */
+    public function xsendfile_file(stored_file $file): bool {
+        return $this->xsendfile($file->get_contenthash());
+    }
+
     /**
      * Serve file content using X-Sendfile header.
      * Please make sure that all headers are already sent and the all

lib/upgrade.txt

@@ -43,6 +43,7 @@ information provided here is intended especially for developers.
 * External functions can be called without requiring a session lock if they define 'readonlysession' => true in
   db/services.php. Note - this also requires $CFG->enable_read_only_sessions to be set to true.
 * database_manager::check_database_schema() now checks for missing and extra indexes.
+* Implement a more direct xsendfile_file() method for an alternative_file_system_class
 
 === 3.8 ===
 * Add CLI option to notify all cron tasks to stop: admin/cli/cron.php --stop