The Tor Browser: ipc/chromium/src/base/lazy

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

     1 // Copyright (c) 2008 The Chromium Authors. All rights reserved.

     2 // Use of this source code is governed by a BSD-style license that can be

     3 // found in the LICENSE file.

     5 #include "base/lazy_instance.h"

     7 #include "base/at_exit.h"

     8 #include "base/atomicops.h"

     9 #include "base/basictypes.h"

    10 #include "base/platform_thread.h"

    12 namespace base {

    14 void LazyInstanceHelper::EnsureInstance(void* instance,

    15                                         void (*ctor)(void*),

    16                                         void (*dtor)(void*)) {

    17   // Try to create the instance, if we're the first, will go from EMPTY

    18   // to CREATING, otherwise we've already been beaten here.

    19   if (base::subtle::Acquire_CompareAndSwap(

    20           &state_, STATE_EMPTY, STATE_CREATING) == STATE_EMPTY) {

    21     // Created the instance in the space provided by |instance|.

    22     ctor(instance);

    23     // Instance is created, go from CREATING to CREATED.

    24     base::subtle::Release_Store(&state_, STATE_CREATED);

    25     // Register the destructor callback with AtExitManager.

    26     base::AtExitManager::RegisterCallback(dtor, instance);

    27   } else {

    28     // It's either in the process of being created, or already created.  Spin.

    29     while (base::subtle::NoBarrier_Load(&state_) != STATE_CREATED)

    30       PlatformThread::YieldCurrentThread();

    31   }

    32 }

    34 }  // namespace base

The Tor Browser / file revision