CComObject 和其派生类在ATL中的作用-优快云博客

CComObject 是ATL中用于创建COM对象的模板类，它提供了一种创建和管理COM对象引用计数的方式。CComObjectCached、CComObjectNoLock、CComObjectGlobal、CComObjectStack 和 CComObjectStackEx 是CComObject的派生类，分别用于不同的场景，如缓存、不加锁、全局对象、栈分配等。这些类在COM编程中帮助开发者更方便地实现对象的生命周期管理。
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//Base is the user's class that derives from CComObjectRoot and whatever
//interfaces the user wants to support on the object
template <class Base>
class CComObject : public Base
{
public:
	typedef Base _BaseClass;
	CComObject(void* = NULL) throw()
	{
		_pAtlModule->Lock();
	}
	// Set refcount to -(LONG_MAX/2) to protect destruction and 
	// also catch mismatched Release in debug builds
	virtual ~CComObject() throw()
	{
		m_dwRef = -(LONG_MAX/2);
		FinalRelease();
#ifdef _ATL_DEBUG_INTERFACES
		_AtlDebugInterfacesModule.DeleteNonAddRefThunk(_GetRawUnknown());
#endif
		_pAtlModule->Unlock();
	}
	//If InternalAddRef or InternalRelease is undefined then your class
	//doesn't derive from CComObjectRoot
	STDMETHOD_(ULONG, AddRef)() {return InternalAddRef();}
	STDMETHOD_(ULONG, Release)()
	{
		ULONG l = InternalRelease();
		if (l == 0)
			delete this;
		return l;
	}
	//if _InternalQueryInterface is undefined then you forgot BEGIN_COM_MAP
	STDMETHOD(QueryInterface)(REFIID iid, void ** ppvObject) throw()
	{return _InternalQueryInterface(iid, ppvObject);}
	template <class Q>
	HRESULT STDMETHODCALLTYPE QueryInterface(Q** pp) throw()
	{
		return QueryInterface(__uuidof(Q), (void**)pp);
	}

	static HRESULT WINAPI CreateInstance(CComObject<Base>** pp) throw();
};

template <class Base>
HRESULT WINAPI CComObject<Base>::CreateInstance(CComObject<Base>** pp) throw()
{
	ATLASSERT(pp != NULL);
	if (pp == NULL)
		return E_POINTER;
	*pp = NULL;

	HRESULT hRes = E_OUTOFMEMORY;
	CComObject<Base>* p = NULL;
	ATLTRY(p = new CComObject<Base>())
	if (p != NULL)
	{
		p->SetVoid(NULL);
		p->InternalFinalConstructAddRef();
		hRes = p->_AtlInitialConstruct();
		if (SUCCEEDED(hRes))
			hRes = p->FinalConstruct();
		if (SUCCEEDED(hRes))
			hRes = p->_AtlFinalConstruct();
		p->InternalFinalConstructRelease();
		if (hRes != S_OK)
		{
			delete p;
			p = NULL;
		}
	}
	*pp = p;
	return hRes;
}

//Base is the user's class that derives from CComObjectRoot and whatever
//interfaces the user wants to support on the object
// CComObjectCached is used primarily for class factories in DLL's
// but it is useful anytime you want to cache an object
template <class Base>
class CComObjectCached : public Base
{
public:
	typedef Base _BaseClass;
	CComObjectCached(void* = NULL){}
	// Set refcount to -(LONG_MAX/2) to protect destruction and 
	// also catch mismatched Release in debug builds
	virtual ~CComObjectCached()
	{
		m_dwRef = -(LONG_MAX/2);
		FinalRelease();
#ifdef _ATL_DEBUG_INTERFACES
		_AtlDebugInterfacesModule.DeleteNonAddRefThunk(_GetRawUnknown());
#endif
	}
	//If InternalAddRef or InternalRelease is undefined then your class
	//doesn't derive from CComObjectRoot
	STDMETHOD_(ULONG, AddRef)() throw()
	{
		ULONG l = InternalAddRef();
		if (l == 2)
			_pAtlModule->Lock();
		return l;
	}
	STDMETHOD_(ULONG, Release)() throw()
	{
		ULONG l = InternalRelease();
		if (l == 0)
			delete this;
		else if (l == 1)
			_pAtlModule->Unlock();
		return l;
	}
	//if _InternalQueryInterface is undefined then you forgot BEGIN_COM_MAP
	STDMETHOD(QueryInterface)(REFIID iid, void ** ppvObject) throw()
	{return _InternalQueryInterface(iid, ppvObject);}
	static HRESULT WINAPI CreateInstance(CComObjectCached<Base>** pp) throw();
};

template <class Base>
HRESULT WINAPI CComObjectCached<Base>::CreateInstance(CComObjectCached<Base>** pp) throw()
{
	ATLASSERT(pp != NULL);
	if (pp == NULL)
		return E_POINTER;
	*pp = NULL;

	HRESULT hRes = E_OUTOFMEMORY;
	CComObjectCached<Base>* p = NULL;
	ATLTRY(p = new CComObjectCached<Base>())
	if (p != NULL)
	{
		p->SetVoid(NULL);
		p->InternalFinalConstructAddRef();
		hRes = p->_AtlInitialConstruct();
		if (SUCCEEDED(hRes))
			hRes = p->FinalConstruct();
		if (SUCCEEDED(hRes))
			hRes = p->_AtlFinalConstruct();
		p->InternalFinalConstructRelease();
		if (hRes != S_OK)
		{
			delete p;
			p = NULL;
		}
	}
	*pp = p;
	return hRes;
}


//Base is the user's class that derives from CComObjectRoot and whatever
//interfaces the user wants to support on the object
template <class Base>
class CComObjectNoLock : public Base
{
public:
	typedef Base _BaseClass;
	CComObjectNoLock(void* = NULL){}
	// Set refcount to -(LONG_MAX/2) to protect destruction and 
	// also catch mismatched Release in debug builds

	virtual ~CComObjectNoLock()
	{
		m_dwRef = -(LONG_MAX/2);
		FinalRelease();
#ifdef _ATL_DEBUG_INTERFACES
		_AtlDebugInterfacesModule.DeleteNonAddRefThunk(_GetRawUnknown());
#endif
	}

	//If InternalAddRef or InternalRelease is undefined then your class
	//doesn't derive from CComObjectRoot
	STDMETHOD_(ULONG, AddRef)() throw() {return InternalAddRef();}
	STDMETHOD_(ULONG, Release)() throw()
	{
		ULONG l = InternalRelease();
		if (l == 0)
			delete this;
		return l;
	}
	//if _InternalQueryInterface is undefined then you forgot BEGIN_COM_MAP
	STDMETHOD(QueryInterface)(REFIID iid, void ** ppvObject) throw()
	{return _InternalQueryInterface(iid, ppvObject);}
};


// It is possible for Base not to derive from CComObjectRoot
// However, you will need to provide _InternalQueryInterface
template <class Base>
class CComObjectGlobal : public Base
{
public:
	typedef Base _BaseClass;
	CComObjectGlobal(void* = NULL)
	{
		m_hResFinalConstruct = S_OK;
		__if_exists(FinalConstruct)
		{
			__if_exists(InternalFinalConstructAddRef)
			{
				InternalFinalConstructAddRef();
			}
			m_hResFinalConstruct = _AtlInitialConstruct();
			if (SUCCEEDED(m_hResFinalConstruct))
				m_hResFinalConstruct = FinalConstruct();
			__if_exists(InternalFinalConstructRelease)
			{
				InternalFinalConstructRelease();
			}
		}
	}
	virtual ~CComObjectGlobal()
	{
		__if_exists(FinalRelease)
		{
			FinalRelease();
		}
#ifdef _ATL_DEBUG_INTERFACES
		_AtlDebugInterfacesModule.DeleteNonAddRefThunk(_GetRawUnknown());
#endif
	}

	STDMETHOD_(ULONG, AddRef)() throw()
	{
		return _pAtlModule->Lock();
	}
	STDMETHOD_(ULONG, Release)() throw()
	{
		return _pAtlModule->Unlock();
	}
	STDMETHOD(QueryInterface)(REFIID iid, void ** ppvObject) throw()
	{
		return _InternalQueryInterface(iid, ppvObject);
	}
	HRESULT m_hResFinalConstruct;
};

// It is possible for Base not to derive from CComObjectRoot
// However, you will need to provide FinalConstruct and InternalQueryInterface
template <class Base>
class CComObjectStack : public Base
{
public:
	typedef Base _BaseClass;
	CComObjectStack(void* = NULL)
	{
		m_hResFinalConstruct = _AtlInitialConstruct();
		if (SUCCEEDED(m_hResFinalConstruct))
			m_hResFinalConstruct = FinalConstruct();
	}
	virtual ~CComObjectStack()
	{
		FinalRelease();
#ifdef _ATL_DEBUG_INTERFACES
		_AtlDebugInterfacesModule.DeleteNonAddRefThunk(_GetRawUnknown());
#endif
	}


	STDMETHOD_(ULONG, AddRef)() throw() {ATLASSERT(FALSE);return 0;}
	STDMETHOD_(ULONG, Release)() throw() {ATLASSERT(FALSE);return 0;}
	STDMETHOD(QueryInterface)(REFIID, void**) throw()
	{ATLASSERT(FALSE);return E_NOINTERFACE;}
	HRESULT m_hResFinalConstruct;
};

// Base must be derived from CComObjectRoot
template <class Base>
class CComObjectStackEx : public Base
{
public:
	typedef Base _BaseClass;

	CComObjectStackEx(void* = NULL) 
	{ 
#ifdef _DEBUG
		m_dwRef = 0;
#endif
		m_hResFinalConstruct = _AtlInitialConstruct();
		if (SUCCEEDED(m_hResFinalConstruct))
			m_hResFinalConstruct = FinalConstruct(); 
	}

	virtual ~CComObjectStackEx()
	{
		// This assert indicates mismatched ref counts.
		//
		// The ref count has no control over the
		// lifetime of this object, so you must ensure
		// by some other means that the object remains 
		// alive while clients have references to its interfaces.
		ATLASSUME(m_dwRef == 0);
		FinalRelease();
#ifdef _ATL_DEBUG_INTERFACES
		_AtlDebugInterfacesModule.DeleteNonAddRefThunk(_GetRawUnknown());
#endif
	}

	STDMETHOD_(ULONG, AddRef)() throw()
	{
#ifdef _DEBUG
		return InternalAddRef();
#else
		return 0;
#endif
	}

	STDMETHOD_(ULONG, Release)() throw()
	{
#ifdef _DEBUG
		return InternalRelease();
#else
		return 0;
#endif
	}

	STDMETHOD(QueryInterface)(REFIID iid, void ** ppvObject) throw()
	{
		return _InternalQueryInterface(iid, ppvObject);
	}

	HRESULT m_hResFinalConstruct;
};

template <class Base> //Base must be derived from CComObjectRoot
class CComContainedObject : public Base
{
public:
	typedef Base _BaseClass;
	CComContainedObject(void* pv) {m_pOuterUnknown = (IUnknown*)pv;}
#ifdef _ATL_DEBUG_INTERFACES
	virtual ~CComContainedObject()
	{
		_AtlDebugInterfacesModule.DeleteNonAddRefThunk(_GetRawUnknown());
		_AtlDebugInterfacesModule.DeleteNonAddRefThunk(m_pOuterUnknown);
	}
#endif

	STDMETHOD_(ULONG, AddRef)() throw() {return OuterAddRef();}
	STDMETHOD_(ULONG, Release)() throw() {return OuterRelease();}
	STDMETHOD(QueryInterface)(REFIID iid, void ** ppvObject) throw()
	{
		return OuterQueryInterface(iid, ppvObject);
	}
	template <class Q>
	HRESULT STDMETHODCALLTYPE QueryInterface(Q** pp)
	{
		return QueryInterface(__uuidof(Q), (void**)pp);
	}
	//GetControllingUnknown may be virtual if the Base class has declared
	//DECLARE_GET_CONTROLLING_UNKNOWN()
	IUnknown* GetControllingUnknown() throw()
	{
#ifdef _ATL_DEBUG_INTERFACES
		IUnknown* p;
		_AtlDebugInterfacesModule.AddNonAddRefThunk(m_pOuterUnknown, _T("CComContainedObject"), &p);
		return p;
#else
		return m_pOuterUnknown;
#endif
	}
};

//contained is the user's class that derives from CComObjectRoot and whatever
//interfaces the user wants to support on the object
template <class contained>
class CComAggObject :
	public IUnknown,
	public CComObjectRootEx< typename contained::_ThreadModel::ThreadModelNoCS >
{
public:
	typedef contained _BaseClass;
	CComAggObject(void* pv) : m_contained(pv)
	{
		_pAtlModule->Lock();
	}
	HRESULT _AtlInitialConstruct()
	{
		HRESULT hr = m_contained._AtlInitialConstruct();
		if (SUCCEEDED(hr))
		{
			hr = CComObjectRootEx< typename contained::_ThreadModel::ThreadModelNoCS >::_AtlInitialConstruct();
		}
		return hr;
	}
	//If you get a message that this call is ambiguous then you need to
	// override it in your class and call each base class' version of this
	HRESULT FinalConstruct()
	{
		CComObjectRootEx<contained::_ThreadModel::ThreadModelNoCS>::FinalConstruct();
		return m_contained.FinalConstruct();
	}
	void FinalRelease()
	{
		CComObjectRootEx<contained::_ThreadModel::ThreadModelNoCS>::FinalRelease();
		m_contained.FinalRelease();
	}
	// Set refcount to -(LONG_MAX/2) to protect destruction and 
	// also catch mismatched Release in debug builds
	virtual ~CComAggObject()
	{
		m_dwRef = -(LONG_MAX/2);
		FinalRelease();
#ifdef _ATL_DEBUG_INTERFACES
		_AtlDebugInterfacesModule.DeleteNonAddRefThunk(this);
#endif
		_pAtlModule->Unlock();
	}

	STDMETHOD_(ULONG, AddRef)() {return InternalAddRef();}
	STDMETHOD_(ULONG, Release)()
	{
		ULONG l = InternalRelease();
		if (l == 0)
			delete this;
		return l;
	}
	STDMETHOD(QueryInterface)(REFIID iid, void ** ppvObject)
	{
		ATLASSERT(ppvObject != NULL);
		if (ppvObject == NULL)
			return E_POINTER;
		*ppvObject = NULL;

		HRESULT hRes = S_OK;
		if (InlineIsEqualUnknown(iid))
		{
			*ppvObject = (void*)(IUnknown*)this;
			AddRef();
#ifdef _ATL_DEBUG_INTERFACES
			_AtlDebugInterfacesModule.AddThunk((IUnknown**)ppvObject, (LPCTSTR)contained::_GetEntries()[-1].dw, iid);
#endif // _ATL_DEBUG_INTERFACES
		}
		else
			hRes = m_contained._InternalQueryInterface(iid, ppvObject);
		return hRes;
	}
	template <class Q>
	HRESULT STDMETHODCALLTYPE QueryInterface(Q** pp)
	{
		return QueryInterface(__uuidof(Q), (void**)pp);
	}
	static HRESULT WINAPI CreateInstance(LPUNKNOWN pUnkOuter, CComAggObject<contained>** pp)
	{
		ATLASSERT(pp != NULL);
		if (pp == NULL)
			return E_POINTER;
		*pp = NULL;

		HRESULT hRes = E_OUTOFMEMORY;
		CComAggObject<contained>* p = NULL;
		ATLTRY(p = new CComAggObject<contained>(pUnkOuter))
		if (p != NULL)
		{
			p->SetVoid(NULL);
			p->InternalFinalConstructAddRef();
			hRes = p->_AtlInitialConstruct();
			if (SUCCEEDED(hRes))
				hRes = p->FinalConstruct();
			if (SUCCEEDED(hRes))
				hRes = p->_AtlFinalConstruct();
			p->InternalFinalConstructRelease();
			if (hRes != S_OK)
			{
				delete p;
				p = NULL;
			}
		}
		*pp = p;
		return hRes;
	}

	CComContainedObject<contained> m_contained;
};

///////////////////////////////////////////////////////////////////////////////
// CComPolyObject can be either aggregated or not aggregated

template <class contained>
class CComPolyObject :
	public IUnknown,
	public CComObjectRootEx< typename contained::_ThreadModel::ThreadModelNoCS >
{
public:
	typedef contained _BaseClass;
	CComPolyObject(void* pv) : m_contained(pv ? pv : this)
	{
		_pAtlModule->Lock();
	}
	HRESULT _AtlInitialConstruct()
	{
		HRESULT hr = m_contained._AtlInitialConstruct();
		if (SUCCEEDED(hr))
		{
			hr = CComObjectRootEx< typename contained::_ThreadModel::ThreadModelNoCS >::_AtlInitialConstruct();
		}
		return hr;
	}
	//If you get a message that this call is ambiguous then you need to
	// override it in your class and call each base class' version of this
	HRESULT FinalConstruct()
	{
		InternalAddRef();
		CComObjectRootEx<contained::_ThreadModel::ThreadModelNoCS>::FinalConstruct();
		HRESULT hr = m_contained.FinalConstruct();
		InternalRelease();
		return hr;
	}
	void FinalRelease()
	{
		CComObjectRootEx<contained::_ThreadModel::ThreadModelNoCS>::FinalRelease();
		m_contained.FinalRelease();
	}
	// Set refcount to -(LONG_MAX/2) to protect destruction and 
	// also catch mismatched Release in debug builds
	virtual ~CComPolyObject()
	{
		m_dwRef = -(LONG_MAX/2);
		FinalRelease();
#ifdef _ATL_DEBUG_INTERFACES
		_AtlDebugInterfacesModule.DeleteNonAddRefThunk(this);
#endif
		_pAtlModule->Unlock();
	}

	STDMETHOD_(ULONG, AddRef)() {return InternalAddRef();}
	STDMETHOD_(ULONG, Release)()
	{
		ULONG l = InternalRelease();
		if (l == 0)
			delete this;
		return l;
	}
	STDMETHOD(QueryInterface)(REFIID iid, void ** ppvObject)
	{
#ifndef _ATL_OLEDB_CONFORMANCE_TESTS
		ATLASSERT(ppvObject != NULL);
#endif
		if (ppvObject == NULL)
			return E_POINTER;
		*ppvObject = NULL;

		HRESULT hRes = S_OK;
		if (InlineIsEqualUnknown(iid))
		{
			*ppvObject = (void*)(IUnknown*)this;
			AddRef();
#ifdef _ATL_DEBUG_INTERFACES
			_AtlDebugInterfacesModule.AddThunk((IUnknown**)ppvObject, (LPCTSTR)contained::_GetEntries()[-1].dw, iid);
#endif // _ATL_DEBUG_INTERFACES
		}
		else
			hRes = m_contained._InternalQueryInterface(iid, ppvObject);
		return hRes;
	}
	template <class Q>
	HRESULT STDMETHODCALLTYPE QueryInterface(Q** pp)
	{
		return QueryInterface(__uuidof(Q), (void**)pp);
	}
	static HRESULT WINAPI CreateInstance(LPUNKNOWN pUnkOuter, CComPolyObject<contained>** pp)
	{
		ATLASSERT(pp != NULL);
		if (pp == NULL)
			return E_POINTER;
		*pp = NULL;


		HRESULT hRes = E_OUTOFMEMORY;
		CComPolyObject<contained>* p = NULL;
		ATLTRY(p = new CComPolyObject<contained>(pUnkOuter))
		if (p != NULL)
		{
			p->SetVoid(NULL);
			p->InternalFinalConstructAddRef();
			hRes = p->_AtlInitialConstruct();
			if (SUCCEEDED(hRes))
				hRes = p->FinalConstruct();
			if (SUCCEEDED(hRes))
				hRes = p->_AtlFinalConstruct();
			p->InternalFinalConstructRelease();
			if (hRes != S_OK)
			{
				delete p;
				p = NULL;
			}
		}
		*pp = p;
		return hRes;
	}

	CComContainedObject<contained> m_contained;
};

template <class Base>
class CComTearOffObject : public Base
{
public:
	CComTearOffObject(void* pv)
	{
		ATLASSUME(m_pOwner == NULL);
		m_pOwner = reinterpret_cast<Base::_OwnerClass*>(pv);
		m_pOwner->AddRef();
	}
	// Set refcount to -(LONG_MAX/2) to protect destruction and 
	// also catch mismatched Release in debug builds
	virtual ~CComTearOffObject()
	{
		m_dwRef = -(LONG_MAX/2);
		FinalRelease();
#ifdef _ATL_DEBUG_INTERFACES
		_AtlDebugInterfacesModule.DeleteNonAddRefThunk(_GetRawUnknown());
#endif
		m_pOwner->Release();
	}

	STDMETHOD_(ULONG, AddRef)() throw() {return InternalAddRef();}
	STDMETHOD_(ULONG, Release)() throw()
	{
		ULONG l = InternalRelease();
		if (l == 0)
			delete this;
		return l;
	}
	STDMETHOD(QueryInterface)(REFIID iid, void ** ppvObject) throw()
	{
		return m_pOwner->QueryInterface(iid, ppvObject);
	}
};

template <class contained>
class CComCachedTearOffObject :
	public IUnknown,
	public CComObjectRootEx<typename contained::_ThreadModel::ThreadModelNoCS>
{
public:
	typedef contained _BaseClass;
	CComCachedTearOffObject(void* pv) :
		m_contained(((contained::_OwnerClass*)pv)->GetControllingUnknown())
	{
		ATLASSUME(m_contained.m_pOwner == NULL);
		m_contained.m_pOwner = reinterpret_cast<contained::_OwnerClass*>(pv);
	}
	HRESULT _AtlInitialConstruct()
	{
		HRESULT hr = m_contained._AtlInitialConstruct();
		if (SUCCEEDED(hr))
		{
			hr = CComObjectRootEx< typename contained::_ThreadModel::ThreadModelNoCS >::_AtlInitialConstruct();
		}
		return hr;
	}
	//If you get a message that this call is ambiguous then you need to
	// override it in your class and call each base class' version of this
	HRESULT FinalConstruct()
	{
		CComObjectRootEx<contained::_ThreadModel::ThreadModelNoCS>::FinalConstruct();
		return m_contained.FinalConstruct();
	}
	void FinalRelease()
	{
		CComObjectRootEx<contained::_ThreadModel::ThreadModelNoCS>::FinalRelease();
		m_contained.FinalRelease();
	}
	// Set refcount to -(LONG_MAX/2) to protect destruction and 
	// also catch mismatched Release in debug builds
	virtual ~CComCachedTearOffObject()
	{
		m_dwRef = -(LONG_MAX/2);
		FinalRelease();
#ifdef _ATL_DEBUG_INTERFACES
		_AtlDebugInterfacesModule.DeleteNonAddRefThunk(this);
#endif
	}


	STDMETHOD_(ULONG, AddRef)() {return InternalAddRef();}
	STDMETHOD_(ULONG, Release)()
	{
		ULONG l = InternalRelease();
		if (l == 0)
			delete this;
		return l;
	}
	STDMETHOD(QueryInterface)(REFIID iid, void ** ppvObject)
	{
		ATLASSERT(ppvObject != NULL);
		if (ppvObject == NULL)
			return E_POINTER;
		*ppvObject = NULL;

		HRESULT hRes = S_OK;
		if (InlineIsEqualUnknown(iid))
		{
			*ppvObject = (void*)(IUnknown*)this;
			AddRef();
#ifdef _ATL_DEBUG_INTERFACES
			_AtlDebugInterfacesModule.AddThunk((IUnknown**)ppvObject, (LPCTSTR)contained::_GetEntries()[-1].dw, iid);
#endif // _ATL_DEBUG_INTERFACES
		}
		else
			hRes = m_contained._InternalQueryInterface(iid, ppvObject);
		return hRes;
	}
	CComContainedObject<contained> m_contained;
};