From 638d612c6b7c08c1f7be0d4e75e9f8a6dca1ef19 Mon Sep 17 00:00:00 2001
From: Brian Burkhalter <bpb@openjdk.org>
Date: Wed, 8 Feb 2023 19:20:39 +0000
Subject: [PATCH] 8298478: (fs) Path.of should allow input to include long path
 prefix

Reviewed-by: alanb
---
 .../classes/sun/nio/fs/WindowsPathParser.java | 24 +++++++++++++-
 test/jdk/java/nio/file/Path/PathOps.java      | 32 +++++++++++++++++--
 2 files changed, 53 insertions(+), 3 deletions(-)

diff --git a/src/java.base/windows/classes/sun/nio/fs/WindowsPathParser.java b/src/java.base/windows/classes/sun/nio/fs/WindowsPathParser.java
index a7afbbe0274..6198fbfd5b5 100644
--- a/src/java.base/windows/classes/sun/nio/fs/WindowsPathParser.java
+++ b/src/java.base/windows/classes/sun/nio/fs/WindowsPathParser.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2008, 2023, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -92,6 +92,20 @@ class WindowsPathParser {
      *          Indicates if the path requires to be normalized
      */
     private static Result parse(String input, boolean requireToNormalize) {
+        // if a prefix is present, remove it and note the expected path type
+        final WindowsPathType expectedType;
+        if (input.startsWith("\\\\?\\")) {
+            if (input.startsWith("UNC\\", 4)) {
+                expectedType = WindowsPathType.UNC;
+                input = "\\\\" + input.substring(8);
+            } else {
+                expectedType = WindowsPathType.ABSOLUTE;
+                input = input.substring(4);
+            }
+        } else {
+            expectedType = null;
+        }
+
         String root = "";
         WindowsPathType type = null;
 
@@ -147,6 +161,14 @@ class WindowsPathParser {
             }
         }
 
+        if (expectedType != null && type != expectedType) {
+            if (expectedType == WindowsPathType.ABSOLUTE) { // long path prefix
+                throw new InvalidPathException(input, "Long path prefix can only be used with an absolute path");
+            } else if (expectedType == WindowsPathType.UNC) { // long UNC path prefix
+                throw new InvalidPathException(input, "Long UNC path prefix can only be used with a UNC path");
+            }
+        }
+
         if (requireToNormalize) {
             StringBuilder sb = new StringBuilder(input.length());
             sb.append(root);
diff --git a/test/jdk/java/nio/file/Path/PathOps.java b/test/jdk/java/nio/file/Path/PathOps.java
index d6992c8ed2c..aa37ddb84ac 100644
--- a/test/jdk/java/nio/file/Path/PathOps.java
+++ b/test/jdk/java/nio/file/Path/PathOps.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2008, 2023, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -22,7 +22,7 @@
  */
 
 /* @test
- * @bug 4313887 6838333 6925932 7006126 8037945 8072495 8140449 8254876
+ * @bug 4313887 6838333 6925932 7006126 8037945 8072495 8140449 8254876 8298478
  * @summary Unit test for java.nio.file.Path path operations
  */
 
@@ -1437,6 +1437,34 @@ public class PathOps {
         int h2 = test("c:\\FOO").path().hashCode();
         if (h1 != h2)
             throw new RuntimeException("PathOps failed");
+
+        // long path prefixes
+        test("\\\\?\\C:\\mnt\\file.dat")  // absolute
+            .string("C:\\mnt\\file.dat");
+        test("\\\\?\\\\\\server\\share\\dir\\file.dat")  // UNC
+            .invalid();
+        test("\\\\?\\file.dat")           // relative
+            .invalid();
+        test("\\\\?\\\\file.dat")         // directory-relative
+            .invalid();
+        test("\\\\?\\C:file.dat")         // drive-relative
+            .invalid();
+        test("\\\\?\\")                   // empty
+            .invalid();
+
+        // long UNC path prefixes
+        test("\\\\?\\UNC\\server\\share\\dir\\file.dat")      // UNC
+            .string("\\\\server\\share\\dir\\file.dat");
+        test("\\\\?\\UNC\\server\\share\\C:\\file.dat")       // absolute
+            .invalid();
+        test("\\\\?\\UNC\\file.dat")                          // relative
+            .invalid();
+        test("\\\\?\\UNC\\server\\share\\C:file.dat")         // drive-relative
+            .invalid();
+        test("\\\\?\\UNC")                                    // empty
+            .invalid();
+        test("\\\\?\\UNC\\")                                  // empty
+            .invalid();
     }
 
     static void doUnixTests() {