Line data    Source code

       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 "webrtc/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             : 
      19           0 : WeakReference::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           0 :   checker_.Detach();
      24           0 : }
      25             : 
      26           0 : void WeakReference::Flag::Invalidate() {
      27           0 :   RTC_DCHECK(checker_.CalledSequentially())
      28           0 :       << "WeakPtrs must be invalidated on the same sequence.";
      29           0 :   is_valid_ = false;
      30           0 : }
      31             : 
      32           0 : bool WeakReference::Flag::IsValid() const {
      33           0 :   RTC_DCHECK(checker_.CalledSequentially())
      34           0 :       << "WeakPtrs must be checked on the same sequence.";
      35           0 :   return is_valid_;
      36             : }
      37             : 
      38           0 : WeakReference::Flag::~Flag() {}
      39             : 
      40           0 : WeakReference::WeakReference() {}
      41             : 
      42           0 : WeakReference::WeakReference(const Flag* flag) : flag_(flag) {}
      43             : 
      44           0 : WeakReference::~WeakReference() {}
      45             : 
      46             : WeakReference::WeakReference(WeakReference&& other) = default;
      47             : 
      48             : WeakReference::WeakReference(const WeakReference& other) = default;
      49             : 
      50           0 : bool WeakReference::is_valid() const {
      51           0 :   return flag_.get() && flag_->IsValid();
      52             : }
      53             : 
      54           0 : WeakReferenceOwner::WeakReferenceOwner() {
      55           0 :   checker_.Detach();
      56           0 : }
      57             : 
      58           0 : WeakReferenceOwner::~WeakReferenceOwner() {
      59           0 :   RTC_DCHECK(checker_.CalledSequentially());
      60           0 :   Invalidate();
      61           0 : }
      62             : 
      63           0 : WeakReference WeakReferenceOwner::GetRef() const {
      64           0 :   RTC_DCHECK(checker_.CalledSequentially());
      65             :   // If we hold the last reference to the Flag then create a new one.
      66           0 :   if (!HasRefs())
      67           0 :     flag_ = new RefCountedObject<WeakReference::Flag>();
      68             : 
      69           0 :   return WeakReference(flag_.get());
      70             : }
      71             : 
      72           0 : void WeakReferenceOwner::Invalidate() {
      73           0 :   RTC_DCHECK(checker_.CalledSequentially());
      74           0 :   if (flag_.get()) {
      75           0 :     flag_->Invalidate();
      76           0 :     flag_ = NULL;
      77             :   }
      78           0 : }
      79             : 
      80           0 : WeakPtrBase::WeakPtrBase() {}
      81             : 
      82           0 : WeakPtrBase::~WeakPtrBase() {}
      83             : 
      84           0 : WeakPtrBase::WeakPtrBase(const WeakReference& ref) : ref_(ref) {}
      85             : 
      86             : }  // namespace internal
      87             : }  // namespace rtc