From 24b69b2402de3721d4ac5bbe60b7d21086fc5d99 Mon Sep 17 00:00:00 2001
From: Roeland Jago Douma <roeland@famdouma.nl>
Date: Mon, 7 Sep 2020 20:53:56 +0200
Subject: [PATCH] Fix reading empty files from objectstorage

Since we try to do range requests this will fail hard.
However since empty files are not that interesting to read anyways we
just read from an emptry memory stream.

Signed-off-by: Roeland Jago Douma <roeland@famdouma.nl>
---
 apps/files_external/lib/Lib/Storage/AmazonS3.php     | 10 ++++++++--
 lib/private/Files/ObjectStore/ObjectStoreStorage.php |  5 +++++
 2 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/apps/files_external/lib/Lib/Storage/AmazonS3.php b/apps/files_external/lib/Lib/Storage/AmazonS3.php
index 4a49f70dd5..23f6592581 100644
--- a/apps/files_external/lib/Lib/Storage/AmazonS3.php
+++ b/apps/files_external/lib/Lib/Storage/AmazonS3.php
@@ -404,12 +404,12 @@ class AmazonS3 extends \OC\Files\Storage\Common {
 	 */
 	private function getContentLength($path) {
 		if (isset($this->filesCache[$path])) {
-			return $this->filesCache[$path]['ContentLength'];
+			return (int)$this->filesCache[$path]['ContentLength'];
 		}
 
 		$result = $this->headObject($path);
 		if (isset($result['ContentLength'])) {
-			return $result['ContentLength'];
+			return (int)$result['ContentLength'];
 		}
 
 		return 0;
@@ -506,6 +506,12 @@ class AmazonS3 extends \OC\Files\Storage\Common {
 		switch ($mode) {
 			case 'r':
 			case 'rb':
+				// Don't try to fetch empty files
+				$stat = $this->stat($path);
+				if (is_array($stat) && isset($stat['size']) && $stat['size'] === 0) {
+					return fopen('php://memory', $mode);
+				}
+
 				try {
 					return $this->readObject($path);
 				} catch (S3Exception $e) {
diff --git a/lib/private/Files/ObjectStore/ObjectStoreStorage.php b/lib/private/Files/ObjectStore/ObjectStoreStorage.php
index faa0342935..3a48efcb31 100644
--- a/lib/private/Files/ObjectStore/ObjectStoreStorage.php
+++ b/lib/private/Files/ObjectStore/ObjectStoreStorage.php
@@ -286,6 +286,11 @@ class ObjectStoreStorage extends \OC\Files\Storage\Common {
 			case 'rb':
 				$stat = $this->stat($path);
 				if (is_array($stat)) {
+					// Reading 0 sized files is a waste of time
+					if (isset($stat['size']) && $stat['size'] === 0) {
+						return fopen('php://memory', $mode);
+					}
+
 					try {
 						return $this->objectStore->readObject($this->getURN($stat['fileid']));
 					} catch (NotFoundException $e) {