Merge pull request #6974 from nextcloud/fix-fseek-on-objectstorage

Fix seeking on object storage

lib/private/Files/View.php

@@ -447,8 +447,28 @@ class View {
 		@ob_end_clean();
 		$handle = $this->fopen($path, 'rb');
 		if ($handle) {
-			if (fseek($handle, $from) === 0) {
-				$chunkSize = 8192; // 8 kB chunks
+			$chunkSize = 8192; // 8 kB chunks
+			$startReading = true;
+
+			if ($from !== 0 && $from !== '0' && fseek($handle, $from) !== 0) {
+				// forward file handle via chunked fread because fseek seem to have failed
+
+				$end = $from + 1;
+				while (!feof($handle) && ftell($handle) < $end) {
+					$len = $from - ftell($handle);
+					if ($len > $chunkSize) {
+						$len = $chunkSize;
+					}
+					$result = fread($handle, $len);
+
+					if ($result === false) {
+						$startReading = false;
+						break;
+					}
+				}
+			}
+
+			if ($startReading) {
 				$end = $to + 1;
 				while (!feof($handle) && ftell($handle) < $end) {
 					$len = $end - ftell($handle);