michael@0: /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
michael@0:  *
michael@0:  * This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: // nsWeakReference.cpp
michael@0: 
michael@0: #include "mozilla/Attributes.h"
michael@0: 
michael@0: #include "nsWeakReference.h"
michael@0: #include "nsCOMPtr.h"
michael@0: 
michael@0: class nsWeakReference MOZ_FINAL : public nsIWeakReference
michael@0:   {
michael@0:     public:
michael@0:     // nsISupports...
michael@0:       NS_DECL_ISUPPORTS
michael@0: 
michael@0:     // nsIWeakReference...
michael@0:       NS_DECL_NSIWEAKREFERENCE
michael@0: 
michael@0:     private:
michael@0:       friend class nsSupportsWeakReference;
michael@0: 
michael@0:       nsWeakReference( nsSupportsWeakReference* referent )
michael@0:           : mReferent(referent)
michael@0:           // ...I can only be constructed by an |nsSupportsWeakReference|
michael@0:         {
michael@0:           // nothing else to do here
michael@0:         }
michael@0: 
michael@0:       ~nsWeakReference()
michael@0:            // ...I will only be destroyed by calling |delete| myself.
michael@0:         {
michael@0:           if ( mReferent )
michael@0:             mReferent->NoticeProxyDestruction();
michael@0:         }
michael@0: 
michael@0:       void
michael@0:       NoticeReferentDestruction()
michael@0:           // ...called (only) by an |nsSupportsWeakReference| from _its_ dtor.
michael@0:         {
michael@0:           mReferent = 0;
michael@0:         }
michael@0: 
michael@0:       nsSupportsWeakReference*  mReferent;
michael@0:   };
michael@0: 
michael@0: nsresult
michael@0: nsQueryReferent::operator()( const nsIID& aIID, void** answer ) const
michael@0:   {
michael@0:     nsresult status;
michael@0:     if ( mWeakPtr )
michael@0:       {
michael@0:         if ( NS_FAILED(status = mWeakPtr->QueryReferent(aIID, answer)) )
michael@0:           *answer = 0;
michael@0:       }
michael@0:     else
michael@0:       status = NS_ERROR_NULL_POINTER;
michael@0: 
michael@0:     if ( mErrorPtr )
michael@0:       *mErrorPtr = status;
michael@0:     return status;
michael@0:   }
michael@0: 
michael@0: NS_COM_GLUE nsIWeakReference*  // or else |already_AddRefed<nsIWeakReference>|
michael@0: NS_GetWeakReference( nsISupports* aInstancePtr, nsresult* aErrorPtr )
michael@0:   {
michael@0:     nsresult status;
michael@0: 
michael@0:     nsIWeakReference* result = nullptr;
michael@0: 
michael@0:     if ( aInstancePtr )
michael@0:       {
michael@0:         nsCOMPtr<nsISupportsWeakReference> factoryPtr = do_QueryInterface(aInstancePtr, &status);
michael@0:         if ( factoryPtr )
michael@0:           {
michael@0:             status = factoryPtr->GetWeakReference(&result);
michael@0:           }
michael@0:         // else, |status| has already been set by |do_QueryInterface|
michael@0:       }
michael@0:     else
michael@0:       status = NS_ERROR_NULL_POINTER;
michael@0: 
michael@0:     if ( aErrorPtr )
michael@0:       *aErrorPtr = status;
michael@0:     return result;
michael@0:   }
michael@0: 
michael@0: NS_COM_GLUE nsresult
michael@0: nsSupportsWeakReference::GetWeakReference( nsIWeakReference** aInstancePtr )
michael@0:   {
michael@0:     if ( !aInstancePtr )
michael@0:       return NS_ERROR_NULL_POINTER;
michael@0: 
michael@0:     if ( !mProxy )
michael@0:       mProxy = new nsWeakReference(this);
michael@0:     *aInstancePtr = mProxy;
michael@0: 
michael@0:     nsresult status;
michael@0:     if ( !*aInstancePtr )
michael@0:       status = NS_ERROR_OUT_OF_MEMORY;
michael@0:     else
michael@0:       {
michael@0:         NS_ADDREF(*aInstancePtr);
michael@0:         status = NS_OK;
michael@0:       }
michael@0: 
michael@0:     return status;
michael@0:   }
michael@0: 
michael@0: NS_IMPL_ISUPPORTS(nsWeakReference, nsIWeakReference)
michael@0: 
michael@0: NS_IMETHODIMP
michael@0: nsWeakReference::QueryReferent( const nsIID& aIID, void** aInstancePtr )
michael@0:   {
michael@0:     return mReferent ? mReferent->QueryInterface(aIID, aInstancePtr) : NS_ERROR_NULL_POINTER;
michael@0:   }
michael@0: 
michael@0: void
michael@0: nsSupportsWeakReference::ClearWeakReferences()
michael@0: 	{
michael@0: 		if ( mProxy )
michael@0: 			{
michael@0: 				mProxy->NoticeReferentDestruction();
michael@0: 				mProxy = 0;
michael@0: 			}
michael@0: 	}
michael@0: