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/*
* Copyright 2016 The WebRTC Project Authors. All rights reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#include "rtc_base/weak_ptr.h"
// The implementation is borrowed from chromium except that it does not
// implement SupportsWeakPtr.
namespace rtc {
namespace internal {
WeakReference::Flag::Flag() : is_valid_(true) {
// Flags only become bound when checked for validity, or invalidated,
// so that we can check that later validity/invalidation operations on
// the same Flag take place on the same sequence.
checker_.Detach();
}
void WeakReference::Flag::Invalidate() {
RTC_DCHECK(checker_.IsCurrent())
<< "WeakPtrs must be invalidated on the same sequence.";
is_valid_ = false;
}
bool WeakReference::Flag::IsValid() const {
RTC_DCHECK(checker_.IsCurrent())
<< "WeakPtrs must be checked on the same sequence.";
return is_valid_;
}
WeakReference::Flag::~Flag() {}
WeakReference::WeakReference() {}
WeakReference::WeakReference(const Flag* flag) : flag_(flag) {}
WeakReference::~WeakReference() {}
WeakReference::WeakReference(WeakReference&& other) = default;
WeakReference::WeakReference(const WeakReference& other) = default;
bool WeakReference::is_valid() const {
return flag_.get() && flag_->IsValid();
}
WeakReferenceOwner::WeakReferenceOwner() {}
WeakReferenceOwner::~WeakReferenceOwner() {
Invalidate();
}
WeakReference WeakReferenceOwner::GetRef() const {
// If we hold the last reference to the Flag then create a new one.
if (!HasRefs())
flag_ = new RefCountedObject<WeakReference::Flag>();
return WeakReference(flag_.get());
}
void WeakReferenceOwner::Invalidate() {
if (flag_.get()) {
flag_->Invalidate();
flag_ = nullptr;
}
}
WeakPtrBase::WeakPtrBase() {}
WeakPtrBase::~WeakPtrBase() {}
WeakPtrBase::WeakPtrBase(const WeakReference& ref) : ref_(ref) {}
} // namespace internal
} // namespace rtc
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