weak_ptr.cc revision 90dce4d38c5ff5333bea97d859d4e484e27edf0c
15821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// Copyright (c) 2011 The Chromium Authors. All rights reserved. 25821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// Use of this source code is governed by a BSD-style license that can be 35821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// found in the LICENSE file. 45821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 55821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include "base/memory/weak_ptr.h" 65821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 75821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)namespace base { 85821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)namespace internal { 95821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 105821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)WeakReference::Flag::Flag() : is_valid_(true) { 1190dce4d38c5ff5333bea97d859d4e484e27edf0cTorne (Richard Coles) // Flags only become bound when checked for validity, or invalidated, 1290dce4d38c5ff5333bea97d859d4e484e27edf0cTorne (Richard Coles) // so that we can check that later validity/invalidation operations on 1390dce4d38c5ff5333bea97d859d4e484e27edf0cTorne (Richard Coles) // the same Flag take place on the same thread. 1490dce4d38c5ff5333bea97d859d4e484e27edf0cTorne (Richard Coles) thread_checker_.DetachFromThread(); 155821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} 165821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 175821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)void WeakReference::Flag::Invalidate() { 185821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // The flag being invalidated with a single ref implies that there are no 195821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // weak pointers in existence. Allow deletion on other thread in this case. 2090dce4d38c5ff5333bea97d859d4e484e27edf0cTorne (Richard Coles) DCHECK(thread_checker_.CalledOnValidThread() || HasOneRef()) 2190dce4d38c5ff5333bea97d859d4e484e27edf0cTorne (Richard Coles) << "WeakPtrs must be checked and invalidated on the same thread."; 225821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) is_valid_ = false; 235821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} 245821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 255821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)bool WeakReference::Flag::IsValid() const { 2690dce4d38c5ff5333bea97d859d4e484e27edf0cTorne (Richard Coles) DCHECK(thread_checker_.CalledOnValidThread()) 2790dce4d38c5ff5333bea97d859d4e484e27edf0cTorne (Richard Coles) << "WeakPtrs must be checked and invalidated on the same thread."; 285821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return is_valid_; 295821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} 305821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 315821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)WeakReference::Flag::~Flag() { 325821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} 335821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 345821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)WeakReference::WeakReference() { 355821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} 365821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 375821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)WeakReference::WeakReference(const Flag* flag) : flag_(flag) { 385821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} 395821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 405821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)WeakReference::~WeakReference() { 415821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} 425821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 435821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)bool WeakReference::is_valid() const { 445821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return flag_ && flag_->IsValid(); 455821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} 465821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 475821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)WeakReferenceOwner::WeakReferenceOwner() { 485821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} 495821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 505821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)WeakReferenceOwner::~WeakReferenceOwner() { 515821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) Invalidate(); 525821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} 535821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 545821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)WeakReference WeakReferenceOwner::GetRef() const { 5590dce4d38c5ff5333bea97d859d4e484e27edf0cTorne (Richard Coles) // If we hold the last reference to the Flag then create a new one. 565821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (!HasRefs()) 575821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) flag_ = new WeakReference::Flag(); 5890dce4d38c5ff5333bea97d859d4e484e27edf0cTorne (Richard Coles) 595821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return WeakReference(flag_); 605821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} 615821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 625821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)void WeakReferenceOwner::Invalidate() { 635821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (flag_) { 645821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) flag_->Invalidate(); 655821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) flag_ = NULL; 665821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) } 675821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} 685821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 695821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)WeakPtrBase::WeakPtrBase() { 705821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} 715821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 725821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)WeakPtrBase::~WeakPtrBase() { 735821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} 745821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 755821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)WeakPtrBase::WeakPtrBase(const WeakReference& ref) : ref_(ref) { 765821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} 775821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 785821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} // namespace internal 795821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} // namespace base 80