Filesystem: add View->getPath to the cache api

lib/files/view.php

@@ -932,4 +932,19 @@ class View {
 			return null;
 		}
 	}
+
+	/**
+	 * Get the path of a file by id, relative to the view
+	 *
+	 * Note that the resulting path is not guarantied to be unique for the id, multiple paths can point to the same file
+	 *
+	 * @param int $id
+	 * @return string
+	 */
+	public function getPath($id) {
+		list($storage, $internalPath) = Cache\Cache::getById($id);
+		$mount = Mount::findById($storage);
+		$fullPath = $mount->getMountPoint() . $internalPath;
+		return $this->getRelativePath($fullPath);
+	}
 }

tests/lib/files/view.php

@@ -98,6 +98,29 @@ class View extends \PHPUnit_Framework_TestCase {
 		$this->assertEquals(array(), $rootView->getDirectoryContent('/non/existing'));
 	}
 
+	function testGetPath() {
+		$storage1 = $this->getTestStorage();
+		$storage2 = $this->getTestStorage();
+		$storage3 = $this->getTestStorage();
+		\OC\Files\Filesystem::mount($storage1, array(), '/');
+		\OC\Files\Filesystem::mount($storage2, array(), '/substorage');
+		\OC\Files\Filesystem::mount($storage3, array(), '/folder/anotherstorage');
+
+		$rootView = new \OC\Files\View('');
+
+		$cachedData = $rootView->getFileInfo('/foo.txt');
+		$id1 = $cachedData['fileid'];
+		$this->assertEquals('/foo.txt', $rootView->getPath($id1));
+
+		$cachedData = $rootView->getFileInfo('/substorage/foo.txt');
+		$id2 = $cachedData['fileid'];
+		$this->assertEquals('/substorage/foo.txt', $rootView->getPath($id2));
+
+		$folderView = new \OC\Files\View('/substorage');
+		$this->assertEquals('/foo.txt', $folderView->getPath($id2));
+		$this->assertNull($folderView->getPath($id1));
+	}
+
 	function testMountPointOverwrite() {
 		$storage1 = $this->getTestStorage(false);
 		$storage2 = $this->getTestStorage();