Fix the case where the browser livelocks if we cannot open a file.

base/file_util_win.cc

 // Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/file_util.h"
 
 #include <windows.h>
 #include <propvarutil.h>
 #include <shellapi.h>
 #include <shlobj.h>
@@ skipping 198 matching lines @@
     // it by now, we don't get better off by deleting the new bits.
   }
   return false;
 }
 
 
 bool PathExists(const FilePath& path) {
   return (GetFileAttributes(path.value().c_str()) != INVALID_FILE_ATTRIBUTES);
 }
 
+bool PathIsReadable(const FilePath& path) {
+  HANDLE dir =
+      CreateFile(path.value().c_str(), FILE_READ_DATA,

[wtc, 2010/01/12 19:51:02]

I'm surprised that we have to test if a file is readable
by trying to open it for reading.  But I couldn't find a
suitable Win32 function for this purpose with a quick
search.

In NSPR we're using the CRT function _access:
http://msdn.microsoft.com/en-us/library/1w06ktdy(VS.80).aspx
Not sure if that's better than our solution here.

[agl, 2010/01/25 14:14:09]

Ah, _access looks good. I've switched to using that. Thanks.

+                 FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
+                 NULL, OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS, NULL);
+
+  if (dir == INVALID_HANDLE_VALUE)
+    return false;
+
+  CloseHandle(dir);
+  return true;
+}
+
 bool PathIsWritable(const FilePath& path) {
   HANDLE dir =
       CreateFile(path.value().c_str(), FILE_ADD_FILE,
                  FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
                  NULL, OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS, NULL);
 
   if (dir == INVALID_HANDLE_VALUE)
     return false;
 
   CloseHandle(dir);
@@ skipping 617 matching lines @@
 }
 
 bool HasFileBeenModifiedSince(const FileEnumerator::FindInfo& find_info,
                               const base::Time& cutoff_time) {
   long result = CompareFileTime(&find_info.ftLastWriteTime,
                                 &cutoff_time.ToFileTime());
   return result == 1 || result == 0;
 }
 
 }  // namespace file_util