Perform URI normalization based on the result of checking for actually existing files & folders instead of request parameters only. This should fixe MOVE requests on Linux

main/filesystem-api/src/main/java/org/cryptomator/filesystem/Folder.java

@@ -48,10 +48,12 @@ public interface Folder extends Node {
 	/**
 	 * Returns a file by resolving a path relative to this folder.
 	 * 
-	 * @param path A unix-style path, which is always relative to this folder, no matter if it starts with a slash or not
+	 * @param path A unix-style path, which is always relative to this folder, no matter if it starts with a slash or not. Path must not be empty.
 	 * @return File with the given path relative to this folder
+	 * @throws IllegalArgumentException
+	 *             if relativePath is empty
 	 */
-	default File resolveFile(String relativePath) throws UncheckedIOException {
+	default File resolveFile(String relativePath) throws UncheckedIOException, IllegalArgumentException {
 		return PathResolver.resolveFile(this, relativePath);
 	}
 
@@ -68,8 +70,8 @@ public interface Folder extends Node {
 	/**
 	 * Returns a folder by resolving a path relative to this folder.
 	 * 
-	 * @param path A unix-style path, which is always relative to this folder, no matter if it starts with a slash or not
-	 * @return Folder with the given path relative to this folder
+	 * @param path A unix-style path, which is always relative to this folder, no matter if it starts with a slash or not. Path may be empty.
+	 * @return Folder with the given path relative to this folder. Returns <code>this</code> if path is empty.
 	 */
 	default Folder resolveFolder(String relativePath) throws UncheckedIOException {
 		return PathResolver.resolveFolder(this, relativePath);

main/filesystem-api/src/main/java/org/cryptomator/filesystem/PathResolver.java

@@ -45,6 +45,16 @@ final class PathResolver {
 	 * </tr>
 	 * <tr>
 	 * <td>/foo/bar</td>
+	 * <td>/</td>
+	 * <td>/foo/bar</td>
+	 * </tr>
+	 * <tr>
+	 * <td>/foo/bar</td>
+	 * <td></td>
+	 * <td>/foo/bar</td>
+	 * </tr>
+	 * <tr>
+	 * <td>/foo/bar</td>
 	 * <td>../../..</td>
 	 * <td>Exception</td>
 	 * </tr>
@@ -58,7 +68,7 @@ final class PathResolver {
 	public static Folder resolveFolder(Folder dir, String relativePath) {
 		final String[] fragments = StringUtils.split(relativePath, '/');
 		if (ArrayUtils.isEmpty(fragments)) {
-			throw new IllegalArgumentException("Empty relativePath");
+			return dir;
 		}
 		return resolveFolder(dir, Arrays.stream(fragments).iterator());
 	}
@@ -69,6 +79,8 @@ final class PathResolver {
 	 * @param dir The directory from which to resolve the path.
 	 * @param relativePath The path relative to a given directory.
 	 * @return The file with the given path relative to the given dir.
+	 * @throws IllegalArgumentException
+	 *             if relativePath is empty, as this path would resolve to the directory itself, which obviously can't be a file.
 	 */
 	public static File resolveFile(Folder dir, String relativePath) {
 		final String[] fragments = StringUtils.split(relativePath, '/');

main/filesystem-api/src/test/java/org/cryptomator/filesystem/PathResolverTest.java

@@ -27,6 +27,13 @@ public class PathResolverTest {
 		Mockito.doReturn(baz).when(bar).file("baz");
 	}
 
+	@Test
+	public void testResolveSameFolder() {
+		Assert.assertEquals(foo, PathResolver.resolveFolder(foo, ""));
+		Assert.assertEquals(foo, PathResolver.resolveFolder(foo, "/"));
+		Assert.assertEquals(foo, PathResolver.resolveFolder(foo, "///"));
+	}
+
 	@Test
 	public void testResolveChildFolder() {
 		Assert.assertEquals(bar, PathResolver.resolveFolder(root, "foo/bar"));
@@ -50,11 +57,6 @@ public class PathResolverTest {
 		PathResolver.resolveFolder(root, "..");
 	}
 
-	@Test(expected = IllegalArgumentException.class)
-	public void testResolveFolderWithEmptyPath() {
-		PathResolver.resolveFolder(root, "");
-	}
-
 	@Test(expected = IllegalArgumentException.class)
 	public void testResolveFileWithEmptyPath() {
 		PathResolver.resolveFile(root, "");