ThreadRestrictions: disallow blocking IO on the UI thread

base/nss_util.cc

 // 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.
 
 #include "base/nss_util.h"
 #include "base/nss_util_internal.h"
 
 #include <nss.h>
 #include <plarena.h>
 #include <prerror.h>
 #include <prinit.h>
 #include <prtime.h>
 #include <pk11pub.h>
 #include <secmod.h>
 
 #if defined(OS_LINUX)
 #include <linux/magic.h>
 #include <sys/vfs.h>
 #endif
 
 #include "base/file_util.h"
 #include "base/logging.h"
 #include "base/singleton.h"
 #include "base/stringprintf.h"
+#include "base/thread_restrictions.h"
 
 // USE_NSS means we use NSS for everything crypto-related.  If USE_NSS is not
 // defined, such as on Mac and Windows, we use NSS for SSL only -- we don't
 // use NSS for crypto or certificate verification, and we don't use the NSS
 // certificate and key databases.
 #if defined(USE_NSS)
 #include "base/environment.h"
 #include "base/lock.h"
 #include "base/scoped_ptr.h"
 #endif  // defined(USE_NSS)
@@ skipping 268 matching lines @@
 #endif  // defined(USE_NSS)
 };
 
 }  // namespace
 
 void EnsureNSPRInit() {
   Singleton<NSPRInitSingleton>::get();
 }
 
 void EnsureNSSInit() {
+  // Initializing SSL causes us to do blocking IO.
+  // Temporarily allow it until we fix
+  //   http://code.google.com/p/chromium/issues/detail?id=59847

[willchan no longer on Chromium, 2010/10/27 00:06:18]

The referenced bug is for this happening on the IO thread, which disagrees with
your changelist description.  if this happens on the IO thread, then that's
fine, it's a known bug and it'll be hard to work around.  If it's the UI thread,
then I'm a bit more disturbed.  Can you clarify?

A more anal approach would be to add the ScopedAllowIO higher up so we aren't
allowed to call EnsureNSSInit() on both the UI and IO thread, just whatever code
is calling this from the IO thread.

+  base::ThreadRestrictions::ScopedAllowIO allow_io;
   Singleton<NSSInitSingleton>::get();
 }
 
 #if defined(USE_NSS)
 bool OpenTestNSSDB(const FilePath& path, const char* description) {
   return Singleton<NSSInitSingleton>::get()->OpenTestNSSDB(path, description);
 }
 
 void CloseTestNSSDB() {
   Singleton<NSSInitSingleton>::get()->CloseTestNSSDB();
@@ skipping 40 matching lines @@
   exploded.millisecond  = prxtime.tm_usec / 1000;
 
   return Time::FromUTCExploded(exploded);
 }
 
 PK11SlotInfo* GetDefaultNSSKeySlot() {
   return Singleton<NSSInitSingleton>::get()->GetDefaultKeySlot();
 }
 
 }  // namespace base