1.CComSingleThreadModel和CComMultiThreadModel特征類：
class?CComSingleThreadModel
{
public:
????static?ULONG?WINAPI?Increment(LPLONG?p)?throw()?{return?++(*p);}
????static?ULONG?WINAPI?Decrement(LPLONG?p)?throw()?{return?--(*p);}
????typedef?CComFakeCriticalSection?AutoCriticalSection;
????typedef?CComFakeCriticalSection?CriticalSection;
????typedef?CComSingleThreadModel?ThreadModelNoCS;
};
class?CComMultiThreadModel
{
public:
????static?ULONG?WINAPI?Increment(LPLONG?p)?throw()?{return?InterlockedIncrement(p);}
????static?ULONG?WINAPI?Decrement(LPLONG?p)?throw()?{return?InterlockedDecrement(p);}
????typedef?CComAutoCriticalSection?AutoCriticalSection;
????typedef?CComCriticalSection?CriticalSection;
????typedef?CComMultiThreadModelNoCS?ThreadModelNoCS;
};
其中的CFakeCriticalSection定義如下：
class?CComFakeCriticalSection
{
public:
????HRESULT?Lock()?throw()?{?return?S_OK;?}
????HRESULT?Unlock()?throw()?{?return?S_OK;?}
????HRESULT?Init()?throw()?{?return?S_OK;?}
????HRESULT?Term()?throw()?{?return?S_OK;?}
};
這兩個類提供了針對特定套間對象的同步控制支持。
CComSingleThreadModel適用于單線程套間對象，它不采用任何線程同步機制；CComMultiThreadModel適用于多線程套間對象，它使用win32的同步機制來實現(xiàn)。
2.CComObjectRootEx模板類
template?<class?ThreadModel>
class?CComObjectRootEx?:?public?CComObjectRootBase
{
public:
????typedef?ThreadModel?_ThreadModel;
????typedef?typename?_ThreadModel::AutoCriticalSection?_CritSec;
????typedef?CComObjectLockT<_ThreadModel>?ObjectLock;
????ULONG?InternalAddRef()
????{
????????return?_ThreadModel::Increment(&m_dwRef);
????}
????ULONG?InternalRelease()
????{
????????return?_ThreadModel::Decrement(&m_dwRef);
????}
????void?Lock()?{m_critsec.Lock();}
????void?Unlock()?{m_critsec.Unlock();}
private:
????_CritSec?m_critsec;
};
它使用傳入的線程模型特征類來實現(xiàn)對象獨立存在時所需要的引用計數(shù)支持，同時提供了一個方便對象開發(fā)使用的同步鎖，我們可以使用這個鎖來完成對自定義數(shù)據(jù)訪問的保護。
posted on 2007-04-06 14:39
michael 閱讀(1620)
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