gecko-dev/xpcom/glue/nsWeakReference.cpp

// nsWeakReference.cpp

#include "nsWeakReference.h"
#include "nsCOMPtr.h"

NS_COM nsIWeakReference *
NS_GetWeakReference( nsISupports* aInstance, nsresult* aResult )
	{
		nsresult status;
		if ( !aResult )
			aResult = &status;

		nsCOMPtr<nsISupportsWeakReference> factoryP = do_QueryInterface(aInstance, aResult);

		nsIWeakReference* weakP = 0;
		if ( factoryP )
			status = factoryP->GetWeakReference(&weakP);
		return weakP;
	}

NS_IMETHODIMP
nsSupportsWeakReference::GetWeakReference( nsIWeakReference** aInstancePtr )
	{
		if ( !aInstancePtr )
			return NS_ERROR_NULL_POINTER;

		if ( !mProxy )
			mProxy = new nsWeakReference(this);
		*aInstancePtr = mProxy;

		nsresult status;
		if ( !*aInstancePtr )
			status = NS_NOINTERFACE;
		else
			{
				NS_ADDREF(*aInstancePtr);
				status = NS_OK;
			}

		return status;
	}

NS_IMETHODIMP_(nsrefcnt)
nsWeakReference::AddRef()
	{
		return ++mRefCount;
	}

NS_IMETHODIMP_(nsrefcnt)
nsWeakReference::Release()
	{
		nsrefcnt temp = --mRefCount;
		if ( !mRefCount )
			delete this;
		return temp;
	}

NS_IMETHODIMP
nsWeakReference::QueryInterface( const nsIID& aIID, void** aInstancePtr )
	{
		if ( !aInstancePtr )
			return NS_ERROR_NULL_POINTER;

		if ( aIID.Equals(nsCOMTypeInfo<nsIWeakReference>::GetIID()) )
			*aInstancePtr = NS_STATIC_CAST(nsIWeakReference*, this);
		else if ( aIID.Equals(nsCOMTypeInfo<nsISupports>::GetIID()) )
			*aInstancePtr = NS_STATIC_CAST(nsISupports*, this);
		else
			*aInstancePtr = 0;

		nsresult status;
		if ( !*aInstancePtr )
			status = NS_NOINTERFACE;
		else
			{
				NS_ADDREF( NS_REINTERPRET_CAST(nsISupports*, *aInstancePtr) );
				status = NS_OK;
			}

		return status;
	}

NS_IMETHODIMP
nsWeakReference::QueryReference( const nsIID& aIID, void** aInstancePtr )
	{
		return mReferent ? mReferent->QueryInterface(aIID, aInstancePtr) : NS_ERROR_NULL_POINTER;
	}