Zeroc ICE 源碼分析二 IceUtil

ICE提供了一個跨平臺的c++ middleware,包含在源碼的include/IceUtil中。IceUtil中包含的主要類如下圖所示:


這些類主要提供了3類跨平臺的基礎功能:

1. SmartPoint / SharedPtr 功能。 Shared 中包含了__incRef() 和 __decRef()的方法。並且當 __decRef中的引用計數爲0時會delete this.

Handle在Constructor 和 Destructor 中會調用Shared 的 __incRef() 和 __decRef()方法。如下所示:

#include <iostream>
#include <IceUtil/Handle.h>
#include <IceUtil/Shared.h>

using namespace std;
using namespace IceUtil;

class MyShared : public Shared
{
public:
	MyShared()
	{
		cout << "In function " << __FUNCTION__ << endl;
	}

	virtual ~MyShared()
	{
		cout << "In function " << __FUNCTION__ << endl;
	}
};

Handle<MyShared> GetMyShared()
{
	Handle<MyShared> mySharedHandle = new MyShared();
	Handle<MyShared> mySharedHandle2 = mySharedHandle;
	return mySharedHandle2;
}

void TestMyShared()
{
	Handle<MyShared> shared = GetMyShared();
	cout << "End of function " << __FUNCTION__ << endl;
}

int main()
{
	TestMyShared();
	cout << "End of function " << __FUNCTION__ << endl;
	return 0;
}
2. 線程以及同步機制:ICE提供了線程(Thread),互斥鎖(Mutex)和條件變量(Cond)用於多線程的處理,如下示例所示:

#include <iostream>
#include <IceUtil/Thread.h>
#include <IceUtil/Cond.h>

using namespace std;
using namespace IceUtil;

Mutex mutex;
Cond cond;

class MyThread : public Thread
{
public:
	virtual void run()
	{
		Mutex::Lock lock(mutex);
		cout << "In function " << __FUNCTION__ << " singled with tid " <<
			this->getThreadControl().id() << endl;
		cond.signal();
	}
};

int main()
{
	ThreadPtr thread = new MyThread();
	thread->start();

	// wait for thread execute
	{
		Mutex::Lock lock(mutex);
		cond.wait(lock);
	}

	cout << "Cond wait in function " << __FUNCTION__ << endl;

	thread->getThreadControl().join();
	return 0;
}
3. Monitor封裝了Cond用於喚醒(所有)等待的線程,如下示例:

#include <iostream>
#include <IceUtil/Thread.h>
#include <IceUtil/Monitor.h>

using namespace std;
using namespace IceUtil;

Monitor<Mutex> monitor;

class MyThread : public Thread
{
public:
	virtual void run()
	{
		Monitor<Mutex>::Lock lock(monitor);
		monitor.wait();
		cout << "In function " << __FUNCTION__ << endl;
	}
};

int main()
{
	ThreadPtr thread = new MyThread();
	thread->start();
	{
		cout << "In function " << __FUNCTION__ << endl;
		// give thread time to start waiting
		Sleep(1000);
		Monitor<Mutex>::Lock lock(monitor); // lock monitor
		monitor.notify();
	} // automaitcally call monitor.unlock()

	thread->getThreadControl().join();
	return 0;
}
更多的示例請參考test/IceUtil。

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