files_encryption: Fix getFileSize()

For certain file sizes, we rounded to the wrong chunk number
and the returned bogus results. This should fix
https://github.com/owncloud/mirall/issues/1009

Conflicts:
	apps/files_encryption/tests/util.php

apps/files_encryption/lib/util.php

@@ -508,11 +508,18 @@ class Util {
 		) {
 
 			// get the size from filesystem
-			$fullPath = $this->view->getLocalFile($path);
 			$size = $this->view->filesize($path);
 
+			// fast path, else the calculation for $lastChunkNr is bogus
+			if ($size === 0) {
+				\OC_FileProxy::$enabled = $proxyStatus;
+				return 0;
+			}
+
 			// calculate last chunk nr
-			$lastChunkNr = floor($size / 8192);
+			// next highest is end of chunks, one subtracted is last one
+			// we have to read the last chunk, we can't just calculate it (because of padding etc)
+			$lastChunkNr = ceil($size/ 8192) - 1;
 			$lastChunkSize = $size - ($lastChunkNr * 8192);
 
 			// open stream

apps/files_encryption/tests/util.php

@@ -241,6 +241,34 @@ class Test_Encryption_Util extends \PHPUnit_Framework_TestCase {
 		$this->view->unlink($this->userId . '/files/' . $filename);
 	}
 
+	/**
+<	 * @brief Test that data that is read by the crypto stream wrapper
+	 */
+	function testGetFileSize() {
+		\Test_Encryption_Util::loginHelper(\Test_Encryption_Util::TEST_ENCRYPTION_UTIL_USER1);
+
+		$filename = 'tmp-' . time();
+		$externalFilename = '/' . $this->userId . '/files/' . $filename;
+
+		// Test for 0 byte files
+		$problematicFileSizeData = "";
+		$cryptedFile = $this->view->file_put_contents($externalFilename, $problematicFileSizeData);
+		$this->assertTrue(is_int($cryptedFile));
+		$this->assertEquals($this->util->getFileSize($externalFilename), 0);
+		$decrypt = $this->view->file_get_contents($externalFilename);
+		$this->assertEquals($problematicFileSizeData, $decrypt);
+		$this->view->unlink($this->userId . '/files/' . $filename);
+
+		// Test a file with 18377 bytes as in https://github.com/owncloud/mirall/issues/1009
+		$problematicFileSizeData = str_pad("", 18377, "abc");
+		$cryptedFile = $this->view->file_put_contents($externalFilename, $problematicFileSizeData);
+		$this->assertTrue(is_int($cryptedFile));
+		$this->assertEquals($this->util->getFileSize($externalFilename), 18377);
+		$decrypt = $this->view->file_get_contents($externalFilename);
+		$this->assertEquals($problematicFileSizeData, $decrypt);
+		$this->view->unlink($this->userId . '/files/' . $filename);
+	}
+
 	/**
 	 * @medium
 	 */
@@ -333,7 +361,7 @@ class Test_Encryption_Util extends \PHPUnit_Framework_TestCase {
 	/**
 	 * helper function to set migration status to the right value
 	 * to be able to test the migration path
-	 * 
+	 *
 	 * @param $status needed migration status for test
 	 * @param $user for which user the status should be set
 	 * @return boolean