1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/xpcom/glue/nsWeakReference.cpp Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,130 @@
1.4 +/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
1.5 + *
1.6 + * This Source Code Form is subject to the terms of the Mozilla Public
1.7 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.8 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.9 +
1.10 +// nsWeakReference.cpp
1.11 +
1.12 +#include "mozilla/Attributes.h"
1.13 +
1.14 +#include "nsWeakReference.h"
1.15 +#include "nsCOMPtr.h"
1.16 +
1.17 +class nsWeakReference MOZ_FINAL : public nsIWeakReference
1.18 + {
1.19 + public:
1.20 + // nsISupports...
1.21 + NS_DECL_ISUPPORTS
1.22 +
1.23 + // nsIWeakReference...
1.24 + NS_DECL_NSIWEAKREFERENCE
1.25 +
1.26 + private:
1.27 + friend class nsSupportsWeakReference;
1.28 +
1.29 + nsWeakReference( nsSupportsWeakReference* referent )
1.30 + : mReferent(referent)
1.31 + // ...I can only be constructed by an |nsSupportsWeakReference|
1.32 + {
1.33 + // nothing else to do here
1.34 + }
1.35 +
1.36 + ~nsWeakReference()
1.37 + // ...I will only be destroyed by calling |delete| myself.
1.38 + {
1.39 + if ( mReferent )
1.40 + mReferent->NoticeProxyDestruction();
1.41 + }
1.42 +
1.43 + void
1.44 + NoticeReferentDestruction()
1.45 + // ...called (only) by an |nsSupportsWeakReference| from _its_ dtor.
1.46 + {
1.47 + mReferent = 0;
1.48 + }
1.49 +
1.50 + nsSupportsWeakReference* mReferent;
1.51 + };
1.52 +
1.53 +nsresult
1.54 +nsQueryReferent::operator()( const nsIID& aIID, void** answer ) const
1.55 + {
1.56 + nsresult status;
1.57 + if ( mWeakPtr )
1.58 + {
1.59 + if ( NS_FAILED(status = mWeakPtr->QueryReferent(aIID, answer)) )
1.60 + *answer = 0;
1.61 + }
1.62 + else
1.63 + status = NS_ERROR_NULL_POINTER;
1.64 +
1.65 + if ( mErrorPtr )
1.66 + *mErrorPtr = status;
1.67 + return status;
1.68 + }
1.69 +
1.70 +NS_COM_GLUE nsIWeakReference* // or else |already_AddRefed<nsIWeakReference>|
1.71 +NS_GetWeakReference( nsISupports* aInstancePtr, nsresult* aErrorPtr )
1.72 + {
1.73 + nsresult status;
1.74 +
1.75 + nsIWeakReference* result = nullptr;
1.76 +
1.77 + if ( aInstancePtr )
1.78 + {
1.79 + nsCOMPtr<nsISupportsWeakReference> factoryPtr = do_QueryInterface(aInstancePtr, &status);
1.80 + if ( factoryPtr )
1.81 + {
1.82 + status = factoryPtr->GetWeakReference(&result);
1.83 + }
1.84 + // else, |status| has already been set by |do_QueryInterface|
1.85 + }
1.86 + else
1.87 + status = NS_ERROR_NULL_POINTER;
1.88 +
1.89 + if ( aErrorPtr )
1.90 + *aErrorPtr = status;
1.91 + return result;
1.92 + }
1.93 +
1.94 +NS_COM_GLUE nsresult
1.95 +nsSupportsWeakReference::GetWeakReference( nsIWeakReference** aInstancePtr )
1.96 + {
1.97 + if ( !aInstancePtr )
1.98 + return NS_ERROR_NULL_POINTER;
1.99 +
1.100 + if ( !mProxy )
1.101 + mProxy = new nsWeakReference(this);
1.102 + *aInstancePtr = mProxy;
1.103 +
1.104 + nsresult status;
1.105 + if ( !*aInstancePtr )
1.106 + status = NS_ERROR_OUT_OF_MEMORY;
1.107 + else
1.108 + {
1.109 + NS_ADDREF(*aInstancePtr);
1.110 + status = NS_OK;
1.111 + }
1.112 +
1.113 + return status;
1.114 + }
1.115 +
1.116 +NS_IMPL_ISUPPORTS(nsWeakReference, nsIWeakReference)
1.117 +
1.118 +NS_IMETHODIMP
1.119 +nsWeakReference::QueryReferent( const nsIID& aIID, void** aInstancePtr )
1.120 + {
1.121 + return mReferent ? mReferent->QueryInterface(aIID, aInstancePtr) : NS_ERROR_NULL_POINTER;
1.122 + }
1.123 +
1.124 +void
1.125 +nsSupportsWeakReference::ClearWeakReferences()
1.126 + {
1.127 + if ( mProxy )
1.128 + {
1.129 + mProxy->NoticeReferentDestruction();
1.130 + mProxy = 0;
1.131 + }
1.132 + }
1.133 +
