// 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_pObservedPtr(nullptr) {} explicit ObservedPtr(T* pObservedPtr) : m_pObservedPtr(pObservedPtr) { if (m_pObservedPtr) m_pObservedPtr->AddObservedPtr(this); } ObservedPtr(const ObservedPtr& that) = delete; ~ObservedPtr() { if (m_pObservedPtr) m_pObservedPtr->RemoveObservedPtr(this); } void Reset(T* pObservedPtr = nullptr) { if (m_pObservedPtr) m_pObservedPtr->RemoveObservedPtr(this); m_pObservedPtr = pObservedPtr; if (m_pObservedPtr) m_pObservedPtr->AddObservedPtr(this); } void OnDestroy() { ASSERT(m_pObservedPtr); m_pObservedPtr = nullptr; } ObservedPtr& operator=(const ObservedPtr& that) = delete; bool operator==(const ObservedPtr& that) const { return m_pObservedPtr == that.m_pObservedPtr; } bool operator!=(const ObservedPtr& that) const { return !(*this == that); } explicit operator bool() const { return !!m_pObservedPtr; } T* Get() const { return m_pObservedPtr; } T& operator*() const { return *m_pObservedPtr; } T* operator->() const { return m_pObservedPtr; } private: T* m_pObservedPtr; }; 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_