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| 1 // Copyright (c) 2016, the Dart project authors. Please see the AUTHORS file | 1 // Copyright (c) 2016, the Dart project authors. Please see the AUTHORS file |
| 2 // for details. All rights reserved. Use of this source code is governed by a | 2 // for details. All rights reserved. Use of this source code is governed by a |
| 3 // BSD-style license that can be found in the LICENSE file. | 3 // BSD-style license that can be found in the LICENSE file. |
| 4 | 4 |
| 5 #ifndef RUNTIME_BIN_REFERENCE_COUNTING_H_ | 5 #ifndef RUNTIME_BIN_REFERENCE_COUNTING_H_ |
| 6 #define RUNTIME_BIN_REFERENCE_COUNTING_H_ | 6 #define RUNTIME_BIN_REFERENCE_COUNTING_H_ |
| 7 | 7 |
| 8 #include "vm/atomic.h" | 8 #include "vm/atomic.h" |
| 9 | 9 |
| 10 namespace dart { | 10 namespace dart { |
| 11 namespace bin { | 11 namespace bin { |
| 12 | 12 |
| 13 // Forward declaration. | 13 // Forward declaration. |
| 14 template <class Target> class RefCntReleaseScope; | 14 template <class Target> |
| 15 class RefCntReleaseScope; |
| 15 | 16 |
| 16 // Inherit from this class where instances of the derived class should be | 17 // Inherit from this class where instances of the derived class should be |
| 17 // reference counted. Reference counts on instances are incremented and | 18 // reference counted. Reference counts on instances are incremented and |
| 18 // decremented explicitly with calls to Retain() and Release(). E.g.: | 19 // decremented explicitly with calls to Retain() and Release(). E.g.: |
| 19 // | 20 // |
| 20 // class Foo : public ReferenceCounted<Foo> { | 21 // class Foo : public ReferenceCounted<Foo> { |
| 21 // public: | 22 // public: |
| 22 // Foo() : ReferenceCounted() {} | 23 // Foo() : ReferenceCounted() {} |
| 23 // ... | 24 // ... |
| 24 // }; | 25 // }; |
| 25 // | 26 // |
| 26 // void DoStuffWithAFoo() { | 27 // void DoStuffWithAFoo() { |
| 27 // Foo* foo = new Foo(); // Reference count starts at 1, so no explicit | 28 // Foo* foo = new Foo(); // Reference count starts at 1, so no explicit |
| 28 // // call to Retain is needed after allocation. | 29 // // call to Retain is needed after allocation. |
| 29 // ... | 30 // ... |
| 30 // foo->Release(); | 31 // foo->Release(); |
| 31 // } | 32 // } |
| 32 template <class Derived> | 33 template <class Derived> |
| 33 class ReferenceCounted { | 34 class ReferenceCounted { |
| 34 public: | 35 public: |
| 35 ReferenceCounted() : | 36 ReferenceCounted() : ref_count_(1) {} |
| 36 ref_count_(1) { | |
| 37 } | |
| 38 | 37 |
| 39 ~ReferenceCounted() { | 38 ~ReferenceCounted() { ASSERT(ref_count_ == 0); } |
| 40 ASSERT(ref_count_ == 0); | |
| 41 } | |
| 42 | 39 |
| 43 void Retain() { | 40 void Retain() { |
| 44 uintptr_t old = AtomicOperations::FetchAndIncrement(&ref_count_); | 41 uintptr_t old = AtomicOperations::FetchAndIncrement(&ref_count_); |
| 45 ASSERT(old > 0); | 42 ASSERT(old > 0); |
| 46 } | 43 } |
| 47 | 44 |
| 48 void Release() { | 45 void Release() { |
| 49 uintptr_t old = AtomicOperations::FetchAndDecrement(&ref_count_); | 46 uintptr_t old = AtomicOperations::FetchAndDecrement(&ref_count_); |
| 50 ASSERT(old > 0); | 47 ASSERT(old > 0); |
| 51 if (old == 1) { | 48 if (old == 1) { |
| (...skipping 19 matching lines...) Expand all Loading... |
| 71 // RefCntReleaseScope<Foo> rs(foo); | 68 // RefCntReleaseScope<Foo> rs(foo); |
| 72 // ... | 69 // ... |
| 73 // } | 70 // } |
| 74 template <class Target> | 71 template <class Target> |
| 75 class RefCntReleaseScope { | 72 class RefCntReleaseScope { |
| 76 public: | 73 public: |
| 77 explicit RefCntReleaseScope(ReferenceCounted<Target>* t) : target_(t) { | 74 explicit RefCntReleaseScope(ReferenceCounted<Target>* t) : target_(t) { |
| 78 ASSERT(target_ != NULL); | 75 ASSERT(target_ != NULL); |
| 79 ASSERT(target_->ref_count() > 0); | 76 ASSERT(target_->ref_count() > 0); |
| 80 } | 77 } |
| 81 ~RefCntReleaseScope() { | 78 ~RefCntReleaseScope() { target_->Release(); } |
| 82 target_->Release(); | |
| 83 } | |
| 84 | 79 |
| 85 private: | 80 private: |
| 86 ReferenceCounted<Target>* target_; | 81 ReferenceCounted<Target>* target_; |
| 87 | 82 |
| 88 DISALLOW_ALLOCATION(); | 83 DISALLOW_ALLOCATION(); |
| 89 DISALLOW_COPY_AND_ASSIGN(RefCntReleaseScope); | 84 DISALLOW_COPY_AND_ASSIGN(RefCntReleaseScope); |
| 90 }; | 85 }; |
| 91 | 86 |
| 92 // Instances of RetainedPointer manage Retaining and Releasing reference counted | 87 // Instances of RetainedPointer manage Retaining and Releasing reference counted |
| 93 // objects. There are two ways to use it. First, it can be used as a field in | 88 // objects. There are two ways to use it. First, it can be used as a field in |
| (...skipping 41 matching lines...) Expand 10 before | Expand all | Expand 10 after Loading... |
| 135 void set(ReferenceCounted<Target>* t) { | 130 void set(ReferenceCounted<Target>* t) { |
| 136 if (target_ != NULL) { | 131 if (target_ != NULL) { |
| 137 target_->Release(); | 132 target_->Release(); |
| 138 } | 133 } |
| 139 target_ = t; | 134 target_ = t; |
| 140 if (target_ != NULL) { | 135 if (target_ != NULL) { |
| 141 target_->Retain(); | 136 target_->Retain(); |
| 142 } | 137 } |
| 143 } | 138 } |
| 144 | 139 |
| 145 Target* get() const { | 140 Target* get() const { return static_cast<Target*>(target_); } |
| 146 return static_cast<Target*>(target_); | |
| 147 } | |
| 148 | 141 |
| 149 private: | 142 private: |
| 150 ReferenceCounted<Target>* target_; | 143 ReferenceCounted<Target>* target_; |
| 151 | 144 |
| 152 DISALLOW_ALLOCATION(); | 145 DISALLOW_ALLOCATION(); |
| 153 DISALLOW_COPY_AND_ASSIGN(RetainedPointer); | 146 DISALLOW_COPY_AND_ASSIGN(RetainedPointer); |
| 154 }; | 147 }; |
| 155 | 148 |
| 156 } // namespace bin | 149 } // namespace bin |
| 157 } // namespace dart | 150 } // namespace dart |
| 158 | 151 |
| 159 #endif // RUNTIME_BIN_REFERENCE_COUNTING_H_ | 152 #endif // RUNTIME_BIN_REFERENCE_COUNTING_H_ |
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