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1 // Copyright 2016 The Chromium Authors. All rights reserved. | 1 // Copyright 2016 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/threading/thread_task_runner_handle.h" | 5 #include "base/threading/thread_task_runner_handle.h" |
6 | 6 |
7 #include <utility> | 7 #include <utility> |
8 | 8 |
9 #include "base/lazy_instance.h" | 9 #include "base/lazy_instance.h" |
10 #include "base/logging.h" | 10 #include "base/logging.h" |
| 11 #include "base/memory/ptr_util.h" |
11 #include "base/threading/sequenced_task_runner_handle.h" | 12 #include "base/threading/sequenced_task_runner_handle.h" |
12 #include "base/threading/thread_local.h" | 13 #include "base/threading/thread_local.h" |
13 | 14 |
14 namespace base { | 15 namespace base { |
15 | 16 |
16 namespace { | 17 namespace { |
17 | 18 |
18 base::LazyInstance<base::ThreadLocalPointer<ThreadTaskRunnerHandle>>::Leaky | 19 base::LazyInstance<base::ThreadLocalPointer< |
19 lazy_tls_ptr = LAZY_INSTANCE_INITIALIZER; | 20 const ThreadTaskRunnerHandle::NestedForTesting>>::Leaky lazy_tls_ptr = |
| 21 LAZY_INSTANCE_INITIALIZER; |
20 | 22 |
21 } // namespace | 23 } // namespace |
22 | 24 |
23 // static | 25 // static |
24 scoped_refptr<SingleThreadTaskRunner> ThreadTaskRunnerHandle::Get() { | 26 scoped_refptr<SingleThreadTaskRunner> ThreadTaskRunnerHandle::Get() { |
25 ThreadTaskRunnerHandle* current = lazy_tls_ptr.Pointer()->Get(); | 27 const ThreadTaskRunnerHandle::NestedForTesting* current = |
| 28 lazy_tls_ptr.Pointer()->Get(); |
26 DCHECK(current); | 29 DCHECK(current); |
27 return current->task_runner_; | 30 return current->task_runner_; |
28 } | 31 } |
29 | 32 |
30 // static | 33 // static |
31 bool ThreadTaskRunnerHandle::IsSet() { | 34 bool ThreadTaskRunnerHandle::IsSet() { |
32 return !!lazy_tls_ptr.Pointer()->Get(); | 35 return !!lazy_tls_ptr.Pointer()->Get(); |
33 } | 36 } |
34 | 37 |
35 ThreadTaskRunnerHandle::ThreadTaskRunnerHandle( | 38 ThreadTaskRunnerHandle::ThreadTaskRunnerHandle( |
| 39 scoped_refptr<SingleThreadTaskRunner> task_runner) { |
| 40 // No SequencedTaskRunnerHandle (which includes ThreadTaskRunnerHandles) |
| 41 // should already be set for this thread. Nesting isn't allowed outside of |
| 42 // tests (ref. NestedForTesting). |
| 43 DCHECK(!SequencedTaskRunnerHandle::IsSet()); |
| 44 |
| 45 // After checking that nesting wasn't used outside of tests above, use |
| 46 // NestedForTesting for the assignement logic. |
| 47 handle_ = MakeUnique<NestedForTesting>(std::move(task_runner)); |
| 48 } |
| 49 |
| 50 ThreadTaskRunnerHandle::~ThreadTaskRunnerHandle() = default; |
| 51 |
| 52 ThreadTaskRunnerHandle::NestedForTesting::NestedForTesting( |
36 scoped_refptr<SingleThreadTaskRunner> task_runner) | 53 scoped_refptr<SingleThreadTaskRunner> task_runner) |
37 : task_runner_(std::move(task_runner)) { | 54 : task_runner_(std::move(task_runner)), |
| 55 previous_handle_(lazy_tls_ptr.Pointer()->Get()) { |
38 DCHECK(task_runner_->BelongsToCurrentThread()); | 56 DCHECK(task_runner_->BelongsToCurrentThread()); |
39 // No SequencedTaskRunnerHandle (which includes ThreadTaskRunnerHandles) | |
40 // should already be set for this thread. | |
41 DCHECK(!SequencedTaskRunnerHandle::IsSet()); | |
42 lazy_tls_ptr.Pointer()->Set(this); | 57 lazy_tls_ptr.Pointer()->Set(this); |
43 } | 58 } |
44 | 59 |
45 ThreadTaskRunnerHandle::~ThreadTaskRunnerHandle() { | 60 ThreadTaskRunnerHandle::NestedForTesting::~NestedForTesting() { |
46 DCHECK(task_runner_->BelongsToCurrentThread()); | 61 DCHECK(task_runner_->BelongsToCurrentThread()); |
47 DCHECK_EQ(lazy_tls_ptr.Pointer()->Get(), this); | 62 DCHECK_EQ(lazy_tls_ptr.Pointer()->Get(), this); |
48 lazy_tls_ptr.Pointer()->Set(nullptr); | 63 lazy_tls_ptr.Pointer()->Set(previous_handle_); |
49 } | 64 } |
50 | 65 |
51 } // namespace base | 66 } // namespace base |
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