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Diffstat (limited to 'src/libs/xpcom18a4/xpcom/glue/nsWeakReference.h')
-rw-r--r-- | src/libs/xpcom18a4/xpcom/glue/nsWeakReference.h | 150 |
1 files changed, 150 insertions, 0 deletions
diff --git a/src/libs/xpcom18a4/xpcom/glue/nsWeakReference.h b/src/libs/xpcom18a4/xpcom/glue/nsWeakReference.h new file mode 100644 index 00000000..96e63f22 --- /dev/null +++ b/src/libs/xpcom18a4/xpcom/glue/nsWeakReference.h @@ -0,0 +1,150 @@ +/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- + * + * ***** BEGIN LICENSE BLOCK ***** + * Version: MPL 1.1/GPL 2.0/LGPL 2.1 + * + * The contents of this file are subject to the Mozilla Public License Version + * 1.1 (the "License"); you may not use this file except in compliance with + * the License. You may obtain a copy of the License at + * http://www.mozilla.org/MPL/ + * + * Software distributed under the License is distributed on an "AS IS" basis, + * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License + * for the specific language governing rights and limitations under the + * License. + * + * The Original Code is the Mozilla browser. + * + * The Initial Developer of the Original Code is + * Netscape Communications, Inc. + * Portions created by the Initial Developer are Copyright (C) 1999 + * the Initial Developer. All Rights Reserved. + * + * Contributor(s): + * Scott Collins <scc@netscape.com> + * + * Alternatively, the contents of this file may be used under the terms of + * either of the GNU General Public License Version 2 or later (the "GPL"), + * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"), + * in which case the provisions of the GPL or the LGPL are applicable instead + * of those above. If you wish to allow use of your version of this file only + * under the terms of either the GPL or the LGPL, and not to allow others to + * use your version of this file under the terms of the MPL, indicate your + * decision by deleting the provisions above and replace them with the notice + * and other provisions required by the GPL or the LGPL. If you do not delete + * the provisions above, a recipient may use your version of this file under + * the terms of any one of the MPL, the GPL or the LGPL. + * + * ***** END LICENSE BLOCK ***** */ + +#ifndef nsWeakReference_h__ +#define nsWeakReference_h__ + +// nsWeakReference.h + +#include "nsIWeakReference.h" + +class nsWeakReference; + +#undef IMETHOD_VISIBILITY +#define IMETHOD_VISIBILITY NS_VISIBILITY_DEFAULT + +class NS_COM nsSupportsWeakReference : public nsISupportsWeakReference + { + public: + nsSupportsWeakReference() + : mProxy(0) + { + // nothing else to do here + } + + NS_DECL_NSISUPPORTSWEAKREFERENCE + + protected: + inline ~nsSupportsWeakReference(); + + private: + friend class nsWeakReference; + + void + NoticeProxyDestruction() + // ...called (only) by an |nsWeakReference| from _its_ dtor. + { + mProxy = 0; + } + + nsWeakReference* mProxy; + + protected: + + inline void ClearWeakReferences(); + PRBool HasWeakReferences() const {return mProxy != 0;} + }; + +#undef IMETHOD_VISIBILITY +#define IMETHOD_VISIBILITY NS_VISIBILITY_HIDDEN + +class NS_COM nsWeakReference : public nsIWeakReference + { + public: + // nsISupports... + NS_IMETHOD_(nsrefcnt) AddRef(); + NS_IMETHOD_(nsrefcnt) Release(); + NS_IMETHOD QueryInterface( const nsIID&, void** ); + + // nsIWeakReference... + NS_DECL_NSIWEAKREFERENCE + + private: + friend class nsSupportsWeakReference; + + nsWeakReference( nsSupportsWeakReference* referent ) + : mRefCount(0), + mReferent(referent) + // ...I can only be constructed by an |nsSupportsWeakReference| + { + // nothing else to do here + } + + ~nsWeakReference() + // ...I will only be destroyed by calling |delete| myself. + { + if ( mReferent ) + mReferent->NoticeProxyDestruction(); + } + + void + NoticeReferentDestruction() + // ...called (only) by an |nsSupportsWeakReference| from _its_ dtor. + { + mReferent = 0; + } + + nsrefcnt mRefCount; + nsSupportsWeakReference* mReferent; + }; + +inline +void +nsSupportsWeakReference::ClearWeakReferences() + /* + Usually being called from |nsSupportsWeakReference::~nsSupportsWeakReference| + will be good enough, but you may have a case where you need to call disconnect + your weak references in an outer destructor (to prevent some client holding a + weak reference from re-entering your destructor). + */ + { + if ( mProxy ) + { + mProxy->NoticeReferentDestruction(); + mProxy = 0; + } + } + +inline +nsSupportsWeakReference::~nsSupportsWeakReference() + { + ClearWeakReferences(); + } + +#endif |