// Copyright 2016 PDFium Authors. All rights reserved. // Use of this source code is governed by a BSD-style license that can be // found in the LICENSE file. #ifndef CORE_FXCRT_CFX_OBSERVABLE_H_ #define CORE_FXCRT_CFX_OBSERVABLE_H_ #include <set> #include "core/fxcrt/fx_system.h" #include "third_party/base/stl_util.h" template <class T> class CFX_Observable { public: class ObservedPtr { public: ObservedPtr() : m_pObservable(nullptr) {} explicit ObservedPtr(T* pObservable) : m_pObservable(pObservable) { if (m_pObservable) m_pObservable->AddObservedPtr(this); } ObservedPtr(const ObservedPtr& that) : ObservedPtr(that.Get()) {} ~ObservedPtr() { if (m_pObservable) m_pObservable->RemoveObservedPtr(this); } void Reset(T* pObservable = nullptr) { if (m_pObservable) m_pObservable->RemoveObservedPtr(this); m_pObservable = pObservable; if (m_pObservable) m_pObservable->AddObservedPtr(this); } void OnDestroy() { ASSERT(m_pObservable); m_pObservable = nullptr; } ObservedPtr& operator=(const ObservedPtr& that) { Reset(that.Get()); return *this; } bool operator==(const ObservedPtr& that) const { return m_pObservable == that.m_pObservable; } bool operator!=(const ObservedPtr& that) const { return !(*this == that); } explicit operator bool() const { return !!m_pObservable; } T* Get() const { return m_pObservable; } T& operator*() const { return *m_pObservable; } T* operator->() const { return m_pObservable; } private: T* m_pObservable; }; CFX_Observable() {} CFX_Observable(const CFX_Observable& that) = delete; ~CFX_Observable() { NotifyObservedPtrs(); } void AddObservedPtr(ObservedPtr* pObservedPtr) { ASSERT(!pdfium::ContainsKey(m_ObservedPtrs, pObservedPtr)); m_ObservedPtrs.insert(pObservedPtr); } void RemoveObservedPtr(ObservedPtr* pObservedPtr) { ASSERT(pdfium::ContainsKey(m_ObservedPtrs, pObservedPtr)); m_ObservedPtrs.erase(pObservedPtr); } void NotifyObservedPtrs() { for (auto* pObservedPtr : m_ObservedPtrs) pObservedPtr->OnDestroy(); m_ObservedPtrs.clear(); } CFX_Observable& operator=(const CFX_Observable& that) = delete; protected: size_t ActiveObservedPtrsForTesting() const { return m_ObservedPtrs.size(); } private: std::set<ObservedPtr*> m_ObservedPtrs; }; #endif // CORE_FXCRT_CFX_OBSERVABLE_H_