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1 // Copyright (c) 2011 The Chromium Authors. All rights reserved. | 1 // Copyright (c) 2011 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/memory/weak_ptr.h" | 5 #include "base/memory/weak_ptr.h" |
6 | 6 |
7 #include "base/debug/leak_annotations.h" | |
8 | |
7 namespace base { | 9 namespace base { |
8 namespace internal { | 10 namespace internal { |
9 | 11 |
10 WeakReference::Flag::Flag() : is_valid_(true) { | 12 static constexpr uintptr_t kTrueMask = ~static_cast<uintptr_t>(0); |
gab
2017/07/18 20:31:08
rm "static": it's redundant at file-scope level
hans
2017/07/19 08:08:23
Done.
| |
13 | |
14 WeakReference::Flag::Flag() : is_valid_(kTrueMask) { | |
15 #if DCHECK_IS_ON() | |
11 // Flags only become bound when checked for validity, or invalidated, | 16 // Flags only become bound when checked for validity, or invalidated, |
12 // so that we can check that later validity/invalidation operations on | 17 // so that we can check that later validity/invalidation operations on |
13 // the same Flag take place on the same sequenced thread. | 18 // the same Flag take place on the same sequenced thread. |
14 sequence_checker_.DetachFromSequence(); | 19 sequence_checker_.DetachFromSequence(); |
20 #endif | |
21 } | |
22 | |
23 WeakReference::Flag::Flag(WeakReference::Flag::NullFlagTag) : is_valid_(false) { | |
24 // There is no need for sequence_checker_.DetachFromSequence() because the | |
25 // null flag doesn't participate in the sequence checks. See DCHECK in | |
26 // Invalidate() and IsValid(). | |
27 | |
28 // Keep the object alive perpetually, even when there are no references to it. | |
29 AddRef(); | |
30 } | |
31 | |
32 WeakReference::Flag* WeakReference::Flag::NullFlag() { | |
33 ANNOTATE_SCOPED_MEMORY_LEAK; | |
34 static Flag* g_null_flag = new Flag(kNullFlagTag); | |
35 return g_null_flag; | |
15 } | 36 } |
16 | 37 |
17 void WeakReference::Flag::Invalidate() { | 38 void WeakReference::Flag::Invalidate() { |
39 #if DCHECK_IS_ON() | |
40 if (this == NullFlag()) { | |
41 // The Null Flag does not participate in the sequence checks below. | |
42 // Since its state never changes, it can be accessed from any thread. | |
43 DCHECK(!is_valid_); | |
44 return; | |
45 } | |
18 // The flag being invalidated with a single ref implies that there are no | 46 // The flag being invalidated with a single ref implies that there are no |
19 // weak pointers in existence. Allow deletion on other thread in this case. | 47 // weak pointers in existence. Allow deletion on other thread in this |
48 // case. | |
20 DCHECK(sequence_checker_.CalledOnValidSequence() || HasOneRef()) | 49 DCHECK(sequence_checker_.CalledOnValidSequence() || HasOneRef()) |
21 << "WeakPtrs must be invalidated on the same sequenced thread."; | 50 << "WeakPtrs must be invalidated on the same sequenced thread."; |
22 is_valid_ = false; | 51 #endif |
52 is_valid_ = 0; | |
23 } | 53 } |
24 | 54 |
25 bool WeakReference::Flag::IsValid() const { | 55 WeakReference::Flag::~Flag() {} |
26 DCHECK(sequence_checker_.CalledOnValidSequence()) | 56 |
27 << "WeakPtrs must be checked on the same sequenced thread."; | 57 WeakReference::WeakReference() : flag_(Flag::NullFlag()) {} |
28 return is_valid_; | 58 |
59 WeakReference::~WeakReference() {} | |
60 | |
61 WeakReference::WeakReference(const Flag* flag) : flag_(flag) {} | |
62 | |
63 WeakReference::WeakReference(WeakReference&& other) | |
64 : flag_(std::move(other.flag_)) { | |
65 other.flag_ = Flag::NullFlag(); | |
29 } | 66 } |
30 | 67 |
31 WeakReference::Flag::~Flag() { | |
32 } | |
33 | |
34 WeakReference::WeakReference() { | |
35 } | |
36 | |
37 WeakReference::WeakReference(const Flag* flag) : flag_(flag) { | |
38 } | |
39 | |
40 WeakReference::~WeakReference() { | |
41 } | |
42 | |
43 WeakReference::WeakReference(WeakReference&& other) = default; | |
44 | |
45 WeakReference::WeakReference(const WeakReference& other) = default; | 68 WeakReference::WeakReference(const WeakReference& other) = default; |
46 | 69 |
47 bool WeakReference::is_valid() const { return flag_.get() && flag_->IsValid(); } | 70 WeakReferenceOwner::WeakReferenceOwner() |
48 | 71 : flag_(WeakReference::Flag::NullFlag()) {} |
49 WeakReferenceOwner::WeakReferenceOwner() { | |
50 } | |
51 | 72 |
52 WeakReferenceOwner::~WeakReferenceOwner() { | 73 WeakReferenceOwner::~WeakReferenceOwner() { |
53 Invalidate(); | 74 Invalidate(); |
54 } | 75 } |
55 | 76 |
56 WeakReference WeakReferenceOwner::GetRef() const { | 77 WeakReference WeakReferenceOwner::GetRef() const { |
57 // If we hold the last reference to the Flag then create a new one. | 78 // If we hold the last reference to the Flag then create a new one. |
58 if (!HasRefs()) | 79 if (!HasRefs()) |
59 flag_ = new WeakReference::Flag(); | 80 flag_ = new WeakReference::Flag(); |
60 | 81 |
61 return WeakReference(flag_.get()); | 82 return WeakReference(flag_.get()); |
62 } | 83 } |
63 | 84 |
64 void WeakReferenceOwner::Invalidate() { | 85 void WeakReferenceOwner::Invalidate() { |
65 if (flag_.get()) { | 86 if (flag_ != WeakReference::Flag::NullFlag()) { |
66 flag_->Invalidate(); | 87 flag_->Invalidate(); |
67 flag_ = NULL; | 88 flag_ = WeakReference::Flag::NullFlag(); |
68 } | 89 } |
69 } | 90 } |
70 | 91 |
71 WeakPtrBase::WeakPtrBase() : ptr_(0) {} | 92 WeakPtrBase::WeakPtrBase() : ptr_(0) {} |
72 | 93 |
73 WeakPtrBase::~WeakPtrBase() {} | 94 WeakPtrBase::~WeakPtrBase() {} |
74 | 95 |
75 WeakPtrBase::WeakPtrBase(const WeakReference& ref, uintptr_t ptr) | 96 WeakPtrBase::WeakPtrBase(const WeakReference& ref, uintptr_t ptr) |
76 : ref_(ref), ptr_(ptr) {} | 97 : ref_(ref), ptr_(ptr) {} |
77 | 98 |
78 WeakPtrFactoryBase::WeakPtrFactoryBase(uintptr_t ptr) : ptr_(ptr) {} | 99 WeakPtrFactoryBase::WeakPtrFactoryBase(uintptr_t ptr) : ptr_(ptr) {} |
79 | 100 |
80 WeakPtrFactoryBase::~WeakPtrFactoryBase() { | 101 WeakPtrFactoryBase::~WeakPtrFactoryBase() { |
81 ptr_ = 0; | 102 ptr_ = 0; |
82 } | 103 } |
83 | 104 |
84 } // namespace internal | 105 } // namespace internal |
85 } // namespace base | 106 } // namespace base |
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