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// 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_INCLUDE_CFX_OBSERVABLE_H_
#define CORE_FXCRT_INCLUDE_CFX_OBSERVABLE_H_
#include <set>
#include "core/fxcrt/include/fx_system.h"
#include "third_party/base/stl_util.h"
template <class T>
class CFX_Observable {
public:
class Observer {
public:
Observer() : m_pWatchedPtr(nullptr) {}
Observer(T** pWatchedPtr) : m_pWatchedPtr(pWatchedPtr) {
if (m_pWatchedPtr)
(*m_pWatchedPtr)->AddObserver(this);
}
Observer(const Observer& that) = delete;
~Observer() {
if (m_pWatchedPtr)
(*m_pWatchedPtr)->RemoveObserver(this);
}
void SetWatchedPtr(T** pWatchedPtr) {
if (m_pWatchedPtr)
(*m_pWatchedPtr)->RemoveObserver(this);
m_pWatchedPtr = pWatchedPtr;
if (m_pWatchedPtr)
(*m_pWatchedPtr)->AddObserver(this);
}
void OnDestroy() {
ASSERT(m_pWatchedPtr);
*m_pWatchedPtr = nullptr;
m_pWatchedPtr = nullptr;
}
Observer& operator=(const Observer& that) = delete;
private:
T** m_pWatchedPtr;
};
CFX_Observable() {}
CFX_Observable(const CFX_Observable& that) = delete;
~CFX_Observable() {
for (auto* pObserver : m_Observers)
pObserver->OnDestroy();
}
void AddObserver(Observer* pObserver) {
ASSERT(!pdfium::ContainsKey(m_Observers, pObserver));
m_Observers.insert(pObserver);
}
void RemoveObserver(Observer* pObserver) {
ASSERT(pdfium::ContainsKey(m_Observers, pObserver));
m_Observers.erase(pObserver);
}
CFX_Observable& operator=(const CFX_Observable& that) = delete;
private:
std::set<Observer*> m_Observers;
};
#endif // CORE_FXCRT_INCLUDE_CFX_OBSERVABLE_H_
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