8011128: (fs) Files.createDirectory fails if the resolved path is exactly 248 characters long

Reviewed-by: khazra, chegar

src/windows/classes/sun/nio/fs/WindowsFileCopy.java

@@ -224,7 +224,7 @@ class WindowsFileCopy {
                 String linkTarget = WindowsLinkSupport.readLink(source);
                 int flags = SYMBOLIC_LINK_FLAG_DIRECTORY;
                 CreateSymbolicLink(targetPath,
-                                   addPrefixIfNeeded(linkTarget),
+                                   WindowsPath.addPrefixIfNeeded(linkTarget),
                                    flags);
             }
         } catch (WindowsException x) {
@@ -414,7 +414,7 @@ class WindowsFileCopy {
             } else {
                 String linkTarget = WindowsLinkSupport.readLink(source);
                 CreateSymbolicLink(targetPath,
-                                   addPrefixIfNeeded(linkTarget),
+                                   WindowsPath.addPrefixIfNeeded(linkTarget),
                                    SYMBOLIC_LINK_FLAG_DIRECTORY);
             }
         } catch (WindowsException x) {
@@ -502,18 +502,4 @@ class WindowsFileCopy {
             priv.drop();
         }
     }
-
-    /**
-     * Add long path prefix to path if required
-     */
-    private static String addPrefixIfNeeded(String path) {
-        if (path.length() > 248) {
-            if (path.startsWith("\\\\")) {
-                path = "\\\\?\\UNC" + path.substring(1, path.length());
-            } else {
-                path = "\\\\?\\" + path;
-            }
-        }
-        return path;
-    }
 }

src/windows/classes/sun/nio/fs/WindowsLinkSupport.java

@@ -231,7 +231,7 @@ class WindowsLinkSupport {
             int end = (next == -1) ? path.length() : next;
             String search = sb.toString() + path.substring(curr, end);
             try {
-                FirstFile fileData = FindFirstFile(addLongPathPrefixIfNeeded(search));
+                FirstFile fileData = FindFirstFile(WindowsPath.addPrefixIfNeeded(search));
                 FindClose(fileData.handle());
 
                 // if a reparse point is encountered then we must return the
@@ -405,20 +405,6 @@ class WindowsLinkSupport {
         return path;
     }
 
-    /**
-     * Add long path prefix to path if required.
-     */
-    private static String addLongPathPrefixIfNeeded(String path) {
-        if (path.length() > 248) {
-            if (path.startsWith("\\\\")) {
-                path = "\\\\?\\UNC" + path.substring(1, path.length());
-            } else {
-                path = "\\\\?\\" + path;
-            }
-        }
-        return path;
-    }
-
     /**
      * Strip long path or symbolic link prefix from path
      */

src/windows/classes/sun/nio/fs/WindowsPath.java

@@ -283,7 +283,7 @@ class WindowsPath extends AbstractPath {
 
     // Add long path prefix to path if required
     static String addPrefixIfNeeded(String path) {
-        if (path.length() > 248) {
+        if (path.length() > MAX_PATH) {
             if (path.startsWith("\\\\")) {
                 path = "\\\\?\\UNC" + path.substring(1, path.length());
             } else {

test/java/nio/file/Files/NameLimits.java

+/*
+ * Copyright (c) 2013, 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
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/* @test
+ * @bug 8011128
+ * @summary Test file and directory name limits. This test is primarily
+ *   intended to test Files.createDirectory on resolved paths at or around
+ *   the short path limit of 248 on Windows.
+ */
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+
+public class NameLimits {
+
+    static final int MAX_PATH = 255;
+    static final int MIN_PATH = 8;     // arbitrarily chosen
+
+    static Path generatePath(int len) {
+        if (len < MIN_PATH)
+            throw new RuntimeException("Attempting to generate path less than MIN_PATH");
+        StringBuilder sb = new StringBuilder(len);
+        sb.append("name");
+        while (sb.length() < len) {
+            sb.append('X');
+        }
+        return Paths.get(sb.toString());
+    }
+
+    static boolean tryCreateFile(int len) throws IOException {
+        Path name = generatePath(len);
+        try {
+            Files.createFile(name);
+        } catch (IOException ioe) {
+            System.err.format("Unable to create file of length %d (full path %d), %s%n",
+                name.toString().length(), name.toAbsolutePath().toString().length(), ioe);
+            return false;
+        }
+        Files.delete(name);
+        return true;
+    }
+
+    static boolean tryCreateDirectory(int len) throws IOException {
+        Path name = generatePath(len);
+        try {
+            Files.createDirectory(name);
+        } catch (IOException ioe) {
+            System.err.format("Unable to create directory of length %d (full path %d), %s%n",
+                name.toString().length(), name.toAbsolutePath().toString().length(), ioe);
+            return false;
+        }
+        Files.delete(name);
+        return true;
+    }
+
+    public static void main(String[] args) throws Exception {
+        int len;
+
+        // find the maximum file name if MAX_PATH or less
+        len = MAX_PATH;
+        while (!tryCreateFile(len)) {
+            len--;
+        }
+        System.out.format("Testing createFile on paths %d .. %d%n", MIN_PATH, len);
+        while (len >= MIN_PATH) {
+            if (!tryCreateFile(len--))
+                throw new RuntimeException("Test failed");
+        }
+
+        // find the maximum directory name if MAX_PATH or less
+        len = MAX_PATH;
+        while (!tryCreateDirectory(len)) {
+            len--;
+        }
+        System.out.format("Testing createDirectory on paths %d .. %d%n", MIN_PATH, len);
+        while (len >= MIN_PATH) {
+            if (!tryCreateDirectory(len--))
+                throw new RuntimeException("Test failed");
+        }
+    }
+}