1 /* 2 * Copyright 2016 The WebRTC Project Authors. All rights reserved. 3 * 4 * Use of this source code is governed by a BSD-style license 5 * that can be found in the LICENSE file in the root of the source 6 * tree. An additional intellectual property rights grant can be found 7 * in the file PATENTS. All contributing project authors may 8 * be found in the AUTHORS file in the root of the source tree. 9 */ 10 11 #include "rtc_base/weak_ptr.h" 12 13 // The implementation is borrowed from chromium except that it does not 14 // implement SupportsWeakPtr. 15 16 namespace rtc { 17 namespace internal { 18 Flag()19WeakReference::Flag::Flag() : is_valid_(true) { 20 // Flags only become bound when checked for validity, or invalidated, 21 // so that we can check that later validity/invalidation operations on 22 // the same Flag take place on the same sequence. 23 checker_.Detach(); 24 } 25 Invalidate()26void WeakReference::Flag::Invalidate() { 27 RTC_DCHECK(checker_.IsCurrent()) 28 << "WeakPtrs must be invalidated on the same sequence."; 29 is_valid_ = false; 30 } 31 IsValid() const32bool WeakReference::Flag::IsValid() const { 33 RTC_DCHECK(checker_.IsCurrent()) 34 << "WeakPtrs must be checked on the same sequence."; 35 return is_valid_; 36 } 37 ~Flag()38WeakReference::Flag::~Flag() {} 39 WeakReference()40WeakReference::WeakReference() {} 41 WeakReference(const Flag * flag)42WeakReference::WeakReference(const Flag* flag) : flag_(flag) {} 43 ~WeakReference()44WeakReference::~WeakReference() {} 45 46 WeakReference::WeakReference(WeakReference&& other) = default; 47 48 WeakReference::WeakReference(const WeakReference& other) = default; 49 is_valid() const50bool WeakReference::is_valid() const { 51 return flag_.get() && flag_->IsValid(); 52 } 53 WeakReferenceOwner()54WeakReferenceOwner::WeakReferenceOwner() {} 55 ~WeakReferenceOwner()56WeakReferenceOwner::~WeakReferenceOwner() { 57 Invalidate(); 58 } 59 GetRef() const60WeakReference WeakReferenceOwner::GetRef() const { 61 // If we hold the last reference to the Flag then create a new one. 62 if (!HasRefs()) 63 flag_ = new RefCountedObject<WeakReference::Flag>(); 64 65 return WeakReference(flag_.get()); 66 } 67 Invalidate()68void WeakReferenceOwner::Invalidate() { 69 if (flag_.get()) { 70 flag_->Invalidate(); 71 flag_ = nullptr; 72 } 73 } 74 WeakPtrBase()75WeakPtrBase::WeakPtrBase() {} 76 ~WeakPtrBase()77WeakPtrBase::~WeakPtrBase() {} 78 WeakPtrBase(const WeakReference & ref)79WeakPtrBase::WeakPtrBase(const WeakReference& ref) : ref_(ref) {} 80 81 } // namespace internal 82 } // namespace rtc 83