pjs/xpcom/base/nsAgg.h

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10 KiB
C++

/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/*
* The contents of this file are subject to the Netscape Public License
* Version 1.0 (the "NPL"); you may not use this file except in
* compliance with the NPL. You may obtain a copy of the NPL at
* http://www.mozilla.org/NPL/
*
* Software distributed under the NPL is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the NPL
* for the specific language governing rights and limitations under the
* NPL.
*
* The Initial Developer of this code under the NPL is Netscape
* Communications Corporation. Portions created by Netscape are
* Copyright (C) 1998 Netscape Communications Corporation. All Rights
* Reserved.
*/
#ifndef nsAgg_h___
#define nsAgg_h___
#include "nsISupports.h"
/**
* Outer objects can implement nsIOuter if they choose, allowing them to
* get notification if their inner objects (children) are effectively freed.
* This allows them to reset any state associated with the inner object and
* potentially unload it.
*/
class nsIOuter : public nsISupports {
public:
/**
* This method is called whenever an inner object's refcount is about to
* become zero and the inner object should be released by the outer. This
* allows the outer to clean up any state associated with the inner and
* potentially unload the inner object. This method should call
* inner->Release().
*/
NS_IMETHOD
ReleaseInner(nsISupports* inner) = 0;
};
#define NS_IOUTER_IID \
{ /* ea0bf9f0-3d67-11d2-8163-006008119d7a */ \
0xea0bf9f0, \
0x3d67, \
0x11d2, \
{0x81, 0x63, 0x00, 0x60, 0x08, 0x11, 0x9d, 0x7a} \
}
////////////////////////////////////////////////////////////////////////////////
// Put this in your class's declaration:
#define NS_DECL_AGGREGATED \
NS_DECL_ISUPPORTS \
\
protected: \
\
/* You must implement this operation instead of the nsISupports */ \
/* methods if you inherit from nsAggregated. */ \
NS_IMETHOD \
AggregatedQueryInterface(const nsIID& aIID, void** aInstancePtr); \
\
class Internal : public nsISupports { \
public: \
\
Internal() {} \
\
NS_IMETHOD QueryInterface(const nsIID& aIID, \
void** aInstancePtr); \
NS_IMETHOD_(nsrefcnt) AddRef(void); \
NS_IMETHOD_(nsrefcnt) Release(void); \
\
}; \
\
friend class Internal; \
\
nsISupports* fOuter; \
Internal fAggregated; \
\
nsISupports* GetInner(void) { return &fAggregated; } \
\
public: \
// Put this in your class's constructor:
#define NS_INIT_AGGREGATED(outer) \
PR_BEGIN_MACRO \
NS_INIT_REFCNT(); \
fOuter = outer; \
PR_END_MACRO
// Put this in your class's implementation file:
#define NS_IMPL_AGGREGATED(_class) \
NS_IMETHODIMP \
_class::QueryInterface(const nsIID& aIID, void** aInstancePtr) \
{ \
/* try our own interfaces first before delegating to outer */ \
nsresult rslt = AggregatedQueryInterface(aIID, aInstancePtr); \
if (rslt != NS_OK && fOuter) \
return fOuter->QueryInterface(aIID, aInstancePtr); \
else \
return rslt; \
} \
\
NS_IMETHODIMP_(nsrefcnt) \
_class::AddRef(void) \
{ \
++mRefCnt; /* keep track of our refcount as well as outer's */ \
if (fOuter) \
return NS_ADDREF(fOuter); \
else \
return mRefCnt; \
} \
\
NS_IMETHODIMP_(nsrefcnt) \
_class::Release(void) \
{ \
if (fOuter) { \
nsISupports* outer = fOuter; /* in case we release ourself */ \
nsIOuter* outerIntf; \
static NS_DEFINE_IID(kIOuterIID, NS_IOUTER_IID); \
if (mRefCnt == 1 && \
outer->QueryInterface(kIOuterIID, \
(void**)&outerIntf) == NS_OK) { \
outerIntf->ReleaseInner(GetInner()); \
outerIntf->Release(); \
} \
else \
--mRefCnt; /* keep track of our refcount as well as outer's */ \
return outer->Release(); \
} \
else { \
if (--mRefCnt == 0) { \
delete this; \
return 0; \
} \
return mRefCnt; \
} \
} \
\
NS_IMETHODIMP \
_class::Internal::QueryInterface(const nsIID& aIID, void** aInstancePtr) \
{ \
_class* agg = (_class*)((char*)(this) - offsetof(_class, fAggregated)); \
return agg->AggregatedQueryInterface(aIID, aInstancePtr); \
} \
\
NS_IMETHODIMP_(nsrefcnt) \
_class::Internal::AddRef(void) \
{ \
_class* agg = (_class*)((char*)(this) - offsetof(_class, fAggregated)); \
return ++agg->mRefCnt; \
} \
\
NS_IMETHODIMP_(nsrefcnt) \
_class::Internal::Release(void) \
{ \
_class* agg = (_class*)((char*)(this) - offsetof(_class, fAggregated)); \
if (--agg->mRefCnt == 0) { \
delete agg; \
return 0; \
} \
return agg->mRefCnt; \
} \
#endif /* nsAgg_h___ */