Add a unit test to check KeygenHandler's thread-safety

base/nss_util.h

 // Copyright (c) 2010 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.
 
 #ifndef BASE_NSS_UTIL_H_
 #define BASE_NSS_UTIL_H_
 
 #include "base/basictypes.h"
 
+#if defined(USE_NSS)
+class Lock;
+#endif // defined(USE_NSS)

[wtc, 2010/06/21 22:40:53]

Nit: two spaces before the comment.  See the Style Guide under
"Line Comments":
http://google-styleguide.googlecode.com/svn/trunk/cppguide.xml#Implementation...

[davidben, 2010/06/22 02:54:56]

Done.

+
 // This file specifically doesn't depend on any NSS or NSPR headers because it
 // is included by various (non-crypto) parts of chrome to call the
 // initialization functions.
 namespace base {
 
 class Time;
 
 // Initialize NRPR if it isn't already initialized.  This function is
 // thread-safe, and NSPR will only ever be initialized once.  NSPR will be
 // properly shut down on program exit.
 void EnsureNSPRInit();
 
 // Initialize NSS if it isn't already initialized.  This must be called before
 // any other NSS functions.  This function is thread-safe, and NSS will only
 // ever be initialized once.  NSS will be properly shut down on program exit.
 void EnsureNSSInit();
 
 #if defined(OS_CHROMEOS)
 // Open the r/w nssdb that's stored inside the user's encrypted home directory.
 void OpenPersistentNSSDB();
 #endif
 
 // Convert a NSS PRTime value into a base::Time object.
 // We use a int64 instead of PRTime here to avoid depending on NSPR headers.
 Time PRTimeToBaseTime(int64 prtime);
 
+#if defined(USE_NSS)
+// NSS has a bug which can cause a deadlock or stall in some cases when writing
+// to the certDB. It also has a bug which causes concurrent key pair
+// generations to scribble over each other. To work around this, we synchronize
+// writes to the NSS databases with a global lock. The lock is hidden beneath a
+// function for easy disabling when the bug is fixed. Callers should allow for
+// it to return NULL in the future.
+//
+// See https://bugzilla.mozilla.org/show_bug.cgi?id=564011
+Lock* GetNSSWriteLock();
+
+// A helper class that acquires the NSS write Lock while the AutoNSSWriteLock
+// is in scope.
+class AutoNSSWriteLock {
+ public:
+  AutoNSSWriteLock();
+  ~AutoNSSWriteLock();
+ private:
+  Lock *lock_;
+  DISALLOW_COPY_AND_ASSIGN(AutoNSSWriteLock);
+};
+
+#endif // defined(USE_NSS)

[davidben, 2010/06/22 02:54:56]

Also added a space here.

+
 }  // namespace base
 
 #endif  // BASE_NSS_UTIL_H_