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| 1 // Copyright (c) 2008 The Chromium Authors. All rights reserved. | 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 | 2 // Use of this source code is governed by a BSD-style license that can be |
| 3 // found in the LICENSE file. | 3 // found in the LICENSE file. |
| 4 | 4 |
| 5 #include "base/lazy_instance.h" | 5 #include "base/lazy_instance.h" |
| 6 | 6 |
| 7 #include "base/at_exit.h" | 7 #include "base/at_exit.h" |
| 8 #include "base/atomicops.h" | 8 #include "base/atomicops.h" |
| 9 #include "base/dynamic_annotations.h" |
| 9 #include "base/basictypes.h" | 10 #include "base/basictypes.h" |
| 10 #include "base/platform_thread.h" | 11 #include "base/platform_thread.h" |
| 11 | 12 |
| 12 namespace base { | 13 namespace base { |
| 13 | 14 |
| 14 void LazyInstanceHelper::EnsureInstance(void* instance, | 15 void LazyInstanceHelper::EnsureInstance(void* instance, |
| 15 void (*ctor)(void*), | 16 void (*ctor)(void*), |
| 16 void (*dtor)(void*)) { | 17 void (*dtor)(void*)) { |
| 17 // Try to create the instance, if we're the first, will go from EMPTY | 18 // 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 // to CREATING, otherwise we've already been beaten here. |
| 19 if (base::subtle::Acquire_CompareAndSwap( | 20 if (base::subtle::Acquire_CompareAndSwap( |
| 20 &state_, STATE_EMPTY, STATE_CREATING) == STATE_EMPTY) { | 21 &state_, STATE_EMPTY, STATE_CREATING) == STATE_EMPTY) { |
| 21 // Created the instance in the space provided by |instance|. | 22 // Created the instance in the space provided by |instance|. |
| 22 ctor(instance); | 23 ctor(instance); |
| 24 |
| 25 // See the comment to the corresponding HAPPENS_AFTER in Pointer(). |
| 26 ANNOTATE_HAPPENS_BEFORE(&state_); |
| 27 |
| 23 // Instance is created, go from CREATING to CREATED. | 28 // Instance is created, go from CREATING to CREATED. |
| 24 base::subtle::Release_Store(&state_, STATE_CREATED); | 29 base::subtle::Release_Store(&state_, STATE_CREATED); |
| 25 // Register the destructor callback with AtExitManager. | 30 // Register the destructor callback with AtExitManager. |
| 26 base::AtExitManager::RegisterCallback(dtor, instance); | 31 base::AtExitManager::RegisterCallback(dtor, instance); |
| 27 } else { | 32 } else { |
| 28 // It's either in the process of being created, or already created. Spin. | 33 // It's either in the process of being created, or already created. Spin. |
| 29 while (base::subtle::NoBarrier_Load(&state_) != STATE_CREATED) | 34 while (base::subtle::NoBarrier_Load(&state_) != STATE_CREATED) |
| 30 PlatformThread::YieldCurrentThread(); | 35 PlatformThread::YieldCurrentThread(); |
| 31 } | 36 } |
| 32 } | 37 } |
| 33 | 38 |
| 34 } // namespace base | 39 } // namespace base |
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