| // Copyright (c) 2011 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #include "base/memory/weak_ptr.h" |
| |
| namespace base { |
| 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 sequenced thread. |
| sequence_checker_.DetachFromSequence(); |
| } |
| |
| void WeakReference::Flag::Invalidate() { |
| // The flag being invalidated with a single ref implies that there are no |
| // weak pointers in existence. Allow deletion on other thread in this case. |
| DCHECK(sequence_checker_.CalledOnValidSequencedThread() || HasOneRef()) |
| << "WeakPtrs must be invalidated on the same sequenced thread."; |
| is_valid_ = false; |
| } |
| |
| bool WeakReference::Flag::IsValid() const { |
| DCHECK(sequence_checker_.CalledOnValidSequencedThread()) |
| << "WeakPtrs must be checked on the same sequenced thread."; |
| return is_valid_; |
| } |
| |
| WeakReference::Flag::~Flag() { |
| } |
| |
| WeakReference::WeakReference() { |
| } |
| |
| WeakReference::WeakReference(const WeakReference& other) = default; |
| |
| WeakReference::WeakReference(const Flag* flag) : flag_(flag) { |
| } |
| |
| WeakReference::~WeakReference() { |
| } |
| |
| 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 WeakReference::Flag(); |
| |
| return WeakReference(flag_.get()); |
| } |
| |
| void WeakReferenceOwner::Invalidate() { |
| if (flag_.get()) { |
| flag_->Invalidate(); |
| flag_ = NULL; |
| } |
| } |
| |
| WeakPtrBase::WeakPtrBase() { |
| } |
| |
| WeakPtrBase::~WeakPtrBase() { |
| } |
| |
| WeakPtrBase::WeakPtrBase(const WeakReference& ref) : ref_(ref) { |
| } |
| |
| } // namespace internal |
| } // namespace base |