scanner: give more percision about what data is reused during scanning

diff --git a/lib/files/cache/scanner.php b/lib/files/cache/scanner.php
index b94a078bd597e499513b06de8c38481acbbe68d5..4cb856bfaec8719e2fb05839cce48525d2189a33 100644 (file)
--- a/lib/files/cache/scanner.php
+++ b/lib/files/cache/scanner.php
@@ -29,6 +29,9 @@ class Scanner {
        const SCAN_RECURSIVE = true;
        const SCAN_SHALLOW = false;
 
+       const REUSE_ETAG = 1;
+       const REUSE_SIZE = 2;
+
        public function __construct(\OC\Files\Storage\Storage $storage) {
                $this->storage = $storage;
                $this->storageId = $this->storage->getId();
@@ -60,10 +63,10 @@ class Scanner {
         * scan a single file and store it in the cache
         *
         * @param string $file
-        * @param bool $checkExisting check existing folder sizes in the cache instead of always using -1 for folder size
+        * @param int $reuseExisting
         * @return array with metadata of the scanned file
         */
-       public function scanFile($file, $checkExisting = false) {
+       public function scanFile($file, $reuseExisting = 0) {
                if (!self::isPartialFile($file)
                        and !Filesystem::isFileBlacklisted($file)
                ) {
@@ -80,21 +83,22 @@ class Scanner {
                                        }
                                }
                                $newData = $data;
-                               if ($cacheData = $this->cache->get($file)) {
-                                       if ($checkExisting && $data['size'] === -1) {
-                                               $data['size'] = $cacheData['size'];
-                                       }
-                                       if ($data['mtime'] === $cacheData['mtime'] &&
-                                               $data['size'] === $cacheData['size']
-                                       ) {
-                                               $data['etag'] = $cacheData['etag'];
+                               if ($reuseExisting and $cacheData = $this->cache->get($file)) {
+                                       // only reuse data if the file hasn't explicitly changed
+                                       if ($data['mtime'] === $cacheData['mtime']) {
+                                               if (($reuseExisting & self::REUSE_SIZE) && ($data['size'] === -1)) {
+                                                       $data['size'] = $cacheData['size'];
+                                               }
+                                               if ($reuseExisting & self::REUSE_ETAG) {
+                                                       $data['etag'] = $cacheData['etag'];
+                                               }
                                        }
                                        // Only update metadata that has changed
                                        $newData = array_diff($data, $cacheData);
                                }
-                               if (!empty($newData)) {
-                                       $this->cache->put($file, $newData);
-                               }
+                       }
+                       if (!empty($newData)) {
+                               $this->cache->put($file, $newData);
                        }
                        return $data;
                }
@@ -106,10 +110,14 @@ class Scanner {
         *
         * @param string $path
         * @param bool $recursive
+        * @param int $reuse
         * @return int the size of the scanned folder or -1 if the size is unknown at this stage
         */
-       public function scan($path, $recursive = self::SCAN_RECURSIVE) {
-               $this->scanFile($path);
+       public function scan($path, $recursive = self::SCAN_RECURSIVE, $reuse = -1) {
+               if ($reuse === -1) {
+                       $reuse = ($recursive === self::SCAN_SHALLOW) ? self::REUSE_ETAG | self::REUSE_SIZE : 0;
+               }
+               $this->scanFile($path, $reuse);
                return $this->scanChildren($path, $recursive);
        }
 
@@ -118,9 +126,13 @@ class Scanner {
         *
         * @param string $path
         * @param bool $recursive
+        * @param int $reuse
         * @return int the size of the scanned folder or -1 if the size is unknown at this stage
         */
-       public function scanChildren($path, $recursive = self::SCAN_RECURSIVE) {
+       public function scanChildren($path, $recursive = self::SCAN_RECURSIVE, $reuse = -1) {
+               if ($reuse === -1) {
+                       $reuse = ($recursive === self::SCAN_SHALLOW) ? self::REUSE_ETAG | self::REUSE_SIZE : 0;
+               }
                \OC_Hook::emit('\OC\Files\Cache\Scanner', 'scan_folder', array('path' => $path, 'storage' => $this->storageId));
                $size = 0;
                $childQueue = array();
@@ -129,7 +141,7 @@ class Scanner {
                        while ($file = readdir($dh)) {
                                $child = ($path) ? $path . '/' . $file : $file;
                                if (!Filesystem::isIgnoredDir($file)) {
-                                       $data = $this->scanFile($child, $recursive === self::SCAN_SHALLOW);
+                                       $data = $this->scanFile($child, $reuse);
                                        if ($data) {
                                                if ($data['size'] === -1) {
                                                        if ($recursive === self::SCAN_RECURSIVE) {