Observer

#ifndef TEST_OBSERVER_SAFE
#define TEST_OBSERVER_SAFE

#include <stdio.h>
#include <vector>
#include <boost/shared_ptr.hpp>
#include <boost/weak_ptr.hpp>
#include <boost/enable_shared_from_this.hpp>
#include <boost/thread/mutex.hpp>
#include <boost/thread/lock_guard.hpp>

namespace TestObserver
{
	class Observable;
	class Observer : public boost::enable_shared_from_this<Observer>
	{
	public:
		Observer() {}
		virtual ~Observer() {printf("%p is destructed!\n", this);}
		virtual void update() = 0;
		void observe(Observable* vSub);
	protected:
		Observable* m_Suject;
	};

	class Observable
	{
	public:
		Observable() {}
		~Observable() {printf("Observable is destructed!\n");}
		void registerd(boost::weak_ptr<Observer> vObserver)
		{
			m_Observers.push_back(vObserver);
		}

		void notifyObservers()
		{
			boost::lock_guard<boost::mutex> Lock(m_Mutex);
			for (Iterator it = m_Observers.begin(); it != m_Observers.end(); /*++it陷阱*/)
			{
				boost::shared_ptr<Observer> tmpObs(it->lock());
				if (tmpObs)
				{
					tmpObs->update();
					++it;
				}
				else
				{
					printf("notifyObervers erase()\n");
					it = m_Observers.erase(it);
				}
			}
		}

	private:
		boost::mutex m_Mutex;
		std::vector<boost::weak_ptr<Observer>> m_Observers;
		typedef std::vector<boost::weak_ptr<Observer>>::iterator Iterator;
	};

	void Observer::observe(Observable* vSub)
	{
		vSub->registerd(shared_from_this());
		m_Suject = vSub;
	}

	class Foo : public Observer
	{
	public:
		virtual void update()
		{
			printf("Foo::update() %p\n", this);
		}
	};

	void fun_1()
	{
		flg_str("TestObserver::fun_1()");
		Observable subject;
		{
			boost::shared_ptr<Foo> p(new Foo);
			p->observe(&subject);
			subject.notifyObservers();
		}
		subject.notifyObservers();
	}
}
#endif