From f7874bfd672f6061e68be5333625747bd01801e8 Mon Sep 17 00:00:00 2001
From: Vincent Petry <pvince81@owncloud.com>
Date: Tue, 18 Jul 2017 16:09:11 +0200
Subject: [PATCH] Add extra check in case of missing home storage

---
 lib/private/Files/Cache/Scanner.php   |  5 +++
 tests/lib/Files/Cache/ScannerTest.php | 50 +++++++++++++++++++++++++++
 2 files changed, 55 insertions(+)

diff --git a/lib/private/Files/Cache/Scanner.php b/lib/private/Files/Cache/Scanner.php
index 5130676cf849..67e03332dd7a 100644
--- a/lib/private/Files/Cache/Scanner.php
+++ b/lib/private/Files/Cache/Scanner.php
@@ -113,6 +113,11 @@ protected function getData($path) {
 		$data = $this->storage->getMetaData($path);
 		if (is_null($data)) {
 			\OCP\Util::writeLog('OC\Files\Cache\Scanner', "!!! Path '$path' is not accessible or present !!!", \OCP\Util::DEBUG);
+			// Last Line of Defence against potential Metadata-loss
+			if ($this->storage->instanceOfStorage('\OCP\Files\IHomeStorage') && !$this->storage->instanceOfStorage('OCA\Files_Sharing\ISharedStorage') && ($path === '' || $path === 'files')) {
+				\OCP\Util::writeLog('OC\Files\Cache\Scanner', 'Missing important folder "' . $path . '" in home storage!!! - ' . $this->storageId, \OCP\Util::ERROR);
+				throw new \OCP\Files\StorageNotAvailableException('Missing important folder "' . $path . '" in home storage - ' . $this->storageId);
+			}
 		}
 		return $data;
 	}
diff --git a/tests/lib/Files/Cache/ScannerTest.php b/tests/lib/Files/Cache/ScannerTest.php
index 64168a88175e..370f8c03b6fe 100644
--- a/tests/lib/Files/Cache/ScannerTest.php
+++ b/tests/lib/Files/Cache/ScannerTest.php
@@ -343,4 +343,54 @@ public function dataTestIsPartialFile() {
 		];
 	}
 
+	public function failGetDataProvider() {
+		return [
+			// throws for empty path and "files" in home storage
+			[true, false, '', true],
+			[true, true, '', true],
+			[true, false, 'files', true],
+			[true, true, 'files', true],
+
+			// doesn't throw for federated shares (non-home)
+			[false, true, '', false],
+			[false, true, 'files', false],
+
+			// doesn't throw for external storage (non-home)
+			[false, false, '', false],
+			[false, false, 'files', false],
+
+			// doesn't throw for other paths
+			[true, false, 'other', false],
+
+			// doesn't throw if metadata exists
+			[true, false, 'other', false, []],
+		];
+	}
+
+	/**
+	 * @dataProvider failGetDataProvider
+	 */
+	public function testFailGetData($isHomeStorage, $isSharedStorage, $scanPath, $expectedThrown, $metadata = null) {
+		$this->storage = $this->createMock(\OC\Files\Storage\Storage::class);
+		$this->storage->method('getCache')->willReturn($this->createMock(\OCP\Files\Cache\ICache::class));
+		$this->storage->expects($this->any())
+			->method('getMetaData')
+			->willReturn(null);
+		$this->storage->expects($this->any())
+			->method('instanceOfStorage')
+			->will($this->returnValueMap([
+				['\OCP\Files\IHomeStorage', $isHomeStorage],
+				['\OCA\Files_Sharing\ISharedStorage', $isSharedStorage],
+			]));
+		$this->scanner = new \OC\Files\Cache\Scanner($this->storage);
+		$thrown = false;
+		try {
+			$this->scanner->scanFile($scanPath);
+		} catch (\OCP\Files\StorageNotAvailableException $e) {
+			$thrown = true;
+		}
+
+		$this->assertEquals($expectedThrown, $thrown);
+	}
+
 }