skip already decrypted files on decrypt all command

Signed-off-by: Bjoern Schiessle <bjoern@schiessle.org>

lib/private/Encryption/DecryptAll.php

@@ -252,6 +252,12 @@ class DecryptAll {
 	 */
 	protected function decryptFile($path) {
 
+		// skip already decrypted files
+		$fileInfo = $this->rootView->getFileInfo($path);
+		if ($fileInfo !== false && !$fileInfo->isEncrypted()) {
+			return true;
+		}
+
 		$source = $path;
 		$target = $path . '.decrypted.' . $this->getTimestamp();
 

tests/lib/Encryption/DecryptAllTest.php

@@ -311,7 +311,10 @@ class DecryptAllTest extends TestCase {
 
 	}
 
-	public function testDecryptFile() {
+	/**
+	 * @dataProvider dataTrueFalse
+	 */
+	public function testDecryptFile($isEncrypted) {
 
 		$path = 'test.txt';
 
@@ -327,15 +330,26 @@ class DecryptAllTest extends TestCase {
 			->setMethods(['getTimestamp'])
 			->getMock();
 
-		$instance->expects($this->any())->method('getTimestamp')->willReturn(42);
-
-		$this->view->expects($this->once())
-			->method('copy')
-			->with($path, $path . '.decrypted.42');
-		$this->view->expects($this->once())
-			->method('rename')
-			->with($path . '.decrypted.42', $path);
-
+		$fileInfo = $this->createMock(FileInfo::class);
+		$fileInfo->expects($this->any())->method('isEncrypted')
+			->willReturn($isEncrypted);
+		$this->view->expects($this->any())->method('getFileInfo')
+			->willReturn($fileInfo);
+
+		if ($isEncrypted) {
+			$instance->expects($this->any())->method('getTimestamp')->willReturn(42);
+
+			$this->view->expects($this->once())
+				->method('copy')
+				->with($path, $path . '.decrypted.42');
+			$this->view->expects($this->once())
+				->method('rename')
+				->with($path . '.decrypted.42', $path);
+		} else {
+			$instance->expects($this->never())->method('getTimestamp');
+			$this->view->expects($this->never())->method('copy');
+			$this->view->expects($this->never())->method('rename');
+		}
 		$this->assertTrue(
 			$this->invokePrivate($instance, 'decryptFile', [$path])
 		);
@@ -356,6 +370,13 @@ class DecryptAllTest extends TestCase {
 			->setMethods(['getTimestamp'])
 			->getMock();
 
+
+		$fileInfo = $this->createMock(FileInfo::class);
+		$fileInfo->expects($this->any())->method('isEncrypted')
+			->willReturn(true);
+		$this->view->expects($this->any())->method('getFileInfo')
+			->willReturn($fileInfo);
+
 		$instance->expects($this->any())->method('getTimestamp')->willReturn(42);
 
 		$this->view->expects($this->once())