Bug 373640 - nsIFile.parent throws an exception on reaching top of file system on Windows -- should return null. r=bsmedberg

xpcom/io/nsLocalFileWin.cpp

@@ -2191,9 +2191,13 @@ nsLocalFile::GetParent(nsIFile * *aParent)
 
     NS_ENSURE_ARG_POINTER(aParent);
 
-    nsAutoString parentPath(mWorkingPath);
+    // A two-character path must be a drive such as C:, so it has no parent
+    if (mWorkingPath.Length() == 2) {
+        *aParent = nsnull;
+        return NS_OK;
+    }
 
-    PRInt32 offset = parentPath.RFindChar(PRUnichar('\\'));
+    PRInt32 offset = mWorkingPath.RFindChar(PRUnichar('\\'));
     // adding this offset check that was removed in bug 241708 fixes mail
     // directories that aren't relative to/underneath the profile dir.
     // e.g., on a different drive. Before you remove them, please make
@@ -2201,10 +2205,14 @@ nsLocalFile::GetParent(nsIFile * *aParent)
     if (offset == kNotFound)
       return NS_ERROR_FILE_UNRECOGNIZED_PATH;
 
-    if (offset == 1 && parentPath[0] == L'\\') {
+    // A path of the form \\NAME is a top-level path and has no parent
+    if (offset == 1 && mWorkingPath[0] == L'\\') {
         *aParent = nsnull;
         return NS_OK;
     }
+
+    nsAutoString parentPath(mWorkingPath);
+
     if (offset > 0)
         parentPath.Truncate(offset);
     else

xpcom/tests/unit/test_bug332389.js

@@ -12,13 +12,7 @@ function run_test() {
       terminated = true;
       break;
     }
-    try {
-      f = f.parent;
-    }
-    catch (e) {
-      // Exception means we reached the top of a volume, terminate
-      f = null;
-    }
+    f = f.parent;
   }
 
   do_check_true(terminated);

xpcom/tests/unit/test_localfile.js

@@ -0,0 +1,66 @@
+/* -*- Mode: Java; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:set ts=2 sw=2 sts=2 et: */
+/* ***** BEGIN LICENSE BLOCK *****
+ * Version: MPL 1.1/GPL 2.0/LGPL 2.1
+ *
+ * The contents of this file are subject to the Mozilla Public License Version
+ * 1.1 (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ * http://www.mozilla.org/MPL/
+ *
+ * Software distributed under the License is distributed on an "AS IS" basis,
+ * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
+ * for the specific language governing rights and limitations under the
+ * License.
+ *
+ * The Original Code is XPCOM unit tests.
+ *
+ * The Initial Developer of the Original Code is
+ * Jeff Walden <jwalden+code@mit.edu>.
+ * Portions created by the Initial Developer are Copyright (C) 2007
+ * the Initial Developer. All Rights Reserved.
+ *
+ * Contributor(s):
+ *
+ * Alternatively, the contents of this file may be used under the terms of
+ * either the GNU General Public License Version 2 or later (the "GPL"), or
+ * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
+ * in which case the provisions of the GPL or the LGPL are applicable instead
+ * of those above. If you wish to allow use of your version of this file only
+ * under the terms of either the GPL or the LGPL, and not to allow others to
+ * use your version of this file under the terms of the MPL, indicate your
+ * decision by deleting the provisions above and replace them with the notice
+ * and other provisions required by the GPL or the LGPL. If you do not delete
+ * the provisions above, a recipient may use your version of this file under
+ * the terms of any one of the MPL, the GPL or the LGPL.
+ *
+ * ***** END LICENSE BLOCK ***** */
+
+const Cr = Components.results;
+const CC = Components.Constructor;
+
+var LocalFile = CC("@mozilla.org/file/local;1", "nsILocalFile", "initWithPath");
+
+function run_test()
+{
+  test_toplevel_parent_is_null();
+}
+
+function test_toplevel_parent_is_null()
+{
+  try
+  {
+    var lf = new LocalFile("C:\\");
+
+    // not required by API, but a property on which the implementation of
+    // parent == null relies for correctness
+    do_check_true(lf.path.length == 2);
+
+    do_check_true(lf.parent === null);
+  }
+  catch (e)
+  {
+    // not Windows
+    do_check_eq(e.result, Cr.NS_ERROR_FILE_UNRECOGNIZED_PATH);
+  }
+}