Allow the creationg of previews of files stored in appdata

To allow us to create previews of files stored in appdata we need to
construct the view differently.

Signed-off-by: Roeland Jago Douma <roeland@famdouma.nl>

lib/private/Preview/GeneratorHelper.php

@@ -26,6 +26,7 @@
 use OCP\Files\File;
 use OCP\Files\IRootFolder;
 use OCP\Files\SimpleFS\ISimpleFile;
+use OCP\IConfig;
 use OCP\IImage;
 use OCP\Image as OCPImage;
 use OCP\Preview\IProvider;
@@ -38,8 +39,12 @@ class GeneratorHelper {
 	/** @var IRootFolder */
 	private $rootFolder;
 
-	public function __construct(IRootFolder $rootFolder) {
+	/** @var IConfig */
+	private $config;
+
+	public function __construct(IRootFolder $rootFolder, IConfig $config) {
 		$this->rootFolder = $rootFolder;
+		$this->config = $config;
 	}
 
 	/**
@@ -63,13 +68,18 @@ private function getViewAndPath(File $file) {
 		$absPath = ltrim($file->getPath(), '/');
 		$owner = explode('/', $absPath)[0];
 
-		$userFolder = $this->rootFolder->getUserFolder($owner)->getParent();
+		if (strpos($owner, 'appdata_' . $this->config->getSystemValue('instanceid')) !== 0) {
+			$userFolder = $this->rootFolder->getUserFolder($owner)->getParent();
 
-		$nodes = $userFolder->getById($file->getId());
-		$file = $nodes[0];
+			$nodes = $userFolder->getById($file->getId());
+			$file = $nodes[0];
 
-		$view = new View($userFolder->getPath());
-		$path = $userFolder->getRelativePath($file->getPath());
+			$view = new View($userFolder->getPath());
+			$path = $userFolder->getRelativePath($file->getPath());
+		} else {
+			$view = new View($file->getParent()->getPath());
+			$path = $file->getName();
+		}
 
 		return [$view, $path];
 	}

lib/private/PreviewManager.php

@@ -195,7 +195,8 @@ public function getPreview(File $file, $width = -1, $height = -1, $crop = false,
 				$this,
 				$this->appData,
 				new GeneratorHelper(
-					$this->rootFolder
+					$this->rootFolder,
+					$this->config
 				),
 				$this->eventDispatcher
 			);