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| 1 // Copyright 2016 PDFium Authors. All rights reserved. |
| 2 // Use of this source code is governed by a BSD-style license that can be |
| 3 // found in the LICENSE file. |
| 4 |
| 5 #ifndef CORE_FXCRT_INCLUDE_CFX_OBSERVABLE_H_ |
| 6 #define CORE_FXCRT_INCLUDE_CFX_OBSERVABLE_H_ |
| 7 |
| 8 #include <set> |
| 9 |
| 10 #include "core/fxcrt/include/fx_system.h" |
| 11 #include "third_party/base/stl_util.h" |
| 12 |
| 13 template <class T> |
| 14 class CFX_Observable { |
| 15 public: |
| 16 class Observer { |
| 17 public: |
| 18 Observer() : m_pWatchedPtr(nullptr) {} |
| 19 Observer(T** pWatchedPtr) : m_pWatchedPtr(pWatchedPtr) { |
| 20 if (m_pWatchedPtr) |
| 21 (*m_pWatchedPtr)->AddObserver(this); |
| 22 } |
| 23 Observer(const Observer& that) = delete; |
| 24 ~Observer() { |
| 25 if (m_pWatchedPtr) |
| 26 (*m_pWatchedPtr)->RemoveObserver(this); |
| 27 } |
| 28 void SetWatchedPtr(T** pWatchedPtr) { |
| 29 if (m_pWatchedPtr) |
| 30 (*m_pWatchedPtr)->RemoveObserver(this); |
| 31 m_pWatchedPtr = pWatchedPtr; |
| 32 if (m_pWatchedPtr) |
| 33 (*m_pWatchedPtr)->AddObserver(this); |
| 34 } |
| 35 void OnDestroy() { |
| 36 ASSERT(m_pWatchedPtr); |
| 37 *m_pWatchedPtr = nullptr; |
| 38 m_pWatchedPtr = nullptr; |
| 39 } |
| 40 Observer& operator=(const Observer& that) = delete; |
| 41 |
| 42 private: |
| 43 T** m_pWatchedPtr; |
| 44 }; |
| 45 |
| 46 CFX_Observable() {} |
| 47 CFX_Observable(const CFX_Observable& that) = delete; |
| 48 ~CFX_Observable() { |
| 49 for (auto* pObserver : m_Observers) |
| 50 pObserver->OnDestroy(); |
| 51 } |
| 52 void AddObserver(Observer* pObserver) { |
| 53 ASSERT(!pdfium::ContainsKey(m_Observers, pObserver)); |
| 54 m_Observers.insert(pObserver); |
| 55 } |
| 56 void RemoveObserver(Observer* pObserver) { |
| 57 ASSERT(pdfium::ContainsKey(m_Observers, pObserver)); |
| 58 m_Observers.erase(pObserver); |
| 59 } |
| 60 CFX_Observable& operator=(const CFX_Observable& that) = delete; |
| 61 |
| 62 private: |
| 63 std::set<Observer*> m_Observers; |
| 64 }; |
| 65 |
| 66 #endif // CORE_FXCRT_INCLUDE_CFX_OBSERVABLE_H_ |
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