pjs/xpcom/base/nsAgg.h

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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/* ***** 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 mozilla.org code.
*
* The Initial Developer of the Original Code is
* Netscape Communications Corporation.
* Portions created by the Initial Developer are Copyright (C) 1998
* the Initial Developer. All Rights Reserved.
*
* Contributor(s):
*
* 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 nsAgg_h___
#define nsAgg_h___
#include "nsISupports.h"
#include "nsCycleCollectionParticipant.h"
////////////////////////////////////////////////////////////////////////////////
// Put NS_DECL_AGGREGATED or NS_DECL_CYCLE_COLLECTING_AGGREGATED in your class's
// declaration.
#define NS_DECL_AGGREGATED \
NS_DECL_ISUPPORTS \
NS_DECL_AGGREGATED_HELPER
#define NS_DECL_CYCLE_COLLECTING_AGGREGATED \
NS_DECL_CYCLE_COLLECTING_ISUPPORTS \
NS_DECL_AGGREGATED_HELPER
#define NS_DECL_AGGREGATED_HELPER \
public: \
\
/** \
* Returns the nsISupports pointer of the inner object (aka the \
* aggregatee). This pointer is really only useful to the outer object \
* (aka the aggregator), which can use it to hold on to the inner \
* object. Anything else wants the nsISupports pointer of the outer \
* object (gotten by QI'ing inner or outer to nsISupports). This method \
* returns a non-addrefed pointer. \
* @return the nsISupports pointer of the inner object \
*/ \
nsISupports* InnerObject(void) { return &fAggregated; } \
\
/** \
* Returns PR_TRUE if this object is part of an aggregated object. \
*/ \
PRBool IsPartOfAggregated(void) { return fOuter != InnerObject(); } \
\
private: \
\
/* You must implement this operation instead of the nsISupports */ \
/* methods. */ \
nsresult \
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); \
\
NS_DECL_OWNINGTHREAD \
}; \
\
friend class Internal; \
\
nsISupports* fOuter; \
Internal fAggregated; \
\
public: \
#define NS_DECL_AGGREGATED_CYCLE_COLLECTION_CLASS(_class) \
class NS_CYCLE_COLLECTION_INNERCLASS \
: public nsXPCOMCycleCollectionParticipant \
{ \
public: \
NS_IMETHOD Unlink(void *p); \
NS_IMETHOD Traverse(void *p, \
nsCycleCollectionTraversalCallback &cb); \
NS_IMETHOD_(void) UnmarkPurple(nsISupports *p) \
{ \
Downcast(p)->UnmarkPurple(); \
} \
static _class* Downcast(nsISupports* s) \
{ \
return (_class*)((char*)(s) - offsetof(_class, fAggregated)); \
} \
static nsISupports* Upcast(_class *p) \
{ \
return p->InnerObject(); \
} \
}; \
NS_CYCLE_COLLECTION_PARTICIPANT_INSTANCE
// Put this in your class's constructor:
#define NS_INIT_AGGREGATED(outer) \
PR_BEGIN_MACRO \
fOuter = outer ? outer : &fAggregated; \
PR_END_MACRO
// Put this in your class's implementation file:
#define NS_IMPL_AGGREGATED(_class) \
\
NS_IMPL_AGGREGATED_HELPER(_class) \
\
NS_IMETHODIMP_(nsrefcnt) \
_class::Internal::AddRef(void) \
{ \
_class* agg = (_class*)((char*)(this) - offsetof(_class, fAggregated)); \
NS_PRECONDITION(PRInt32(agg->mRefCnt) >= 0, "illegal refcnt"); \
NS_ASSERT_OWNINGTHREAD(_class); \
++agg->mRefCnt; \
NS_LOG_ADDREF(this, agg->mRefCnt, #_class, sizeof(*this)); \
return agg->mRefCnt; \
} \
\
NS_IMETHODIMP_(nsrefcnt) \
_class::Internal::Release(void) \
{ \
_class* agg = (_class*)((char*)(this) - offsetof(_class, fAggregated)); \
NS_PRECONDITION(0 != agg->mRefCnt, "dup release"); \
NS_ASSERT_OWNINGTHREAD(_class); \
--agg->mRefCnt; \
NS_LOG_RELEASE(this, agg->mRefCnt, #_class); \
if (agg->mRefCnt == 0) { \
agg->mRefCnt = 1; /* stabilize */ \
NS_DELETEXPCOM(agg); \
return 0; \
} \
return agg->mRefCnt; \
} \
#define NS_IMPL_CYCLE_COLLECTING_AGGREGATED(_class) \
\
NS_IMPL_AGGREGATED_HELPER(_class) \
\
NS_IMETHODIMP_(nsrefcnt) \
_class::Internal::AddRef(void) \
{ \
_class* agg = NS_CYCLE_COLLECTION_CLASSNAME(_class)::Downcast(this); \
NS_PRECONDITION(PRInt32(agg->mRefCnt) >= 0, "illegal refcnt"); \
NS_CheckThreadSafe(agg->_mOwningThread.GetThread(), \
#_class " not thread-safe"); \
nsrefcnt count = agg->mRefCnt.incr(this); \
NS_LOG_ADDREF(this, count, #_class, sizeof(*agg)); \
return count; \
} \
\
NS_IMETHODIMP_(nsrefcnt) \
_class::Internal::Release(void) \
{ \
_class* agg = NS_CYCLE_COLLECTION_CLASSNAME(_class)::Downcast(this); \
NS_PRECONDITION(0 != agg->mRefCnt, "dup release"); \
NS_CheckThreadSafe(agg->_mOwningThread.GetThread(), \
#_class " not thread-safe"); \
nsrefcnt count = agg->mRefCnt.decr(this); \
NS_LOG_RELEASE(this, count, #_class); \
if (count == 0) { \
agg->mRefCnt.stabilizeForDeletion(this); \
NS_DELETEXPCOM(agg); \
return 0; \
} \
return count; \
}
#define NS_IMPL_AGGREGATED_HELPER(_class) \
NS_IMETHODIMP \
_class::QueryInterface(const nsIID& aIID, void** aInstancePtr) \
{ \
return fOuter->QueryInterface(aIID, aInstancePtr); \
} \
\
NS_IMETHODIMP_(nsrefcnt) \
_class::AddRef(void) \
{ \
return fOuter->AddRef(); \
} \
\
NS_IMETHODIMP_(nsrefcnt) \
_class::Release(void) \
{ \
return fOuter->Release(); \
} \
\
NS_IMETHODIMP \
_class::Internal::QueryInterface(const nsIID& aIID, void** aInstancePtr) \
{ \
_class* agg = (_class*)((char*)(this) - offsetof(_class, fAggregated)); \
return agg->AggregatedQueryInterface(aIID, aInstancePtr); \
} \
/**
* To make aggregated objects participate in cycle collection we need to enable
* the outer object (aggregator) to traverse/unlink the objects held by the
* inner object (the aggregatee). We can't just make the inner object QI'able to
* NS_CYCLECOLLECTIONPARTICIPANT_IID, we don't want to return the inner object's
* nsCycleCollectionParticipant for the outer object (which will happen if the
* outer object doesn't participate in cycle collection itself).
* NS_AGGREGATED_CYCLECOLLECTIONPARTICIPANT_IID enables the outer object to get
* the inner objects nsCycleCollectionParticipant.
*
* There are three cases:
* - No aggregation
* QI'ing to NS_CYCLECOLLECTIONPARTICIPANT_IID will return the inner
* object's nsCycleCollectionParticipant.
*
* - Aggregation and outer object does not participate in cycle collection
* QI'ing to NS_CYCLECOLLECTIONPARTICIPANT_IID will not return anything.
*
* - Aggregation and outer object does participate in cycle collection
* QI'ing to NS_CYCLECOLLECTIONPARTICIPANT_IID will return the outer
* object's nsCycleCollectionParticipant. The outer object's
* nsCycleCollectionParticipant can then QI the inner object to
* NS_AGGREGATED_CYCLECOLLECTIONPARTICIPANT_IID to get the inner object's
* nsCycleCollectionParticipant, which it can use to traverse/unlink the
* objects reachable from the inner object.
*/
#define NS_AGGREGATED_CYCLECOLLECTIONPARTICIPANT_IID \
{ \
0x32889b7e, \
0xe4fe, \
0x43f4, \
{ 0x85, 0x31, 0xb5, 0x28, 0x23, 0xa2, 0xe9, 0xfc } \
}
/**
* Just holds the IID so NS_GET_IID works.
*/
class nsAggregatedCycleCollectionParticipant
{
public:
NS_DECLARE_STATIC_IID_ACCESSOR(NS_AGGREGATED_CYCLECOLLECTIONPARTICIPANT_IID)
};
NS_DEFINE_STATIC_IID_ACCESSOR(nsAggregatedCycleCollectionParticipant,
NS_AGGREGATED_CYCLECOLLECTIONPARTICIPANT_IID)
// for use with QI macros in nsISupportsUtils.h:
#define NS_INTERFACE_MAP_BEGIN_AGGREGATED(_class) \
NS_IMPL_AGGREGATED_QUERY_HEAD(_class)
#define NS_INTERFACE_MAP_ENTRY_CYCLE_COLLECTION_AGGREGATED(_class) \
NS_IMPL_QUERY_CYCLE_COLLECTION(_class)
#define NS_INTERFACE_MAP_ENTRIES_CYCLE_COLLECTION_AGGREGATED(_class) \
NS_INTERFACE_MAP_ENTRY_CYCLE_COLLECTION_AGGREGATED(_class) \
NS_INTERFACE_MAP_ENTRY_CYCLE_COLLECTION_ISUPPORTS(_class)
#define NS_IMPL_AGGREGATED_QUERY_HEAD(_class) \
nsresult \
_class::AggregatedQueryInterface(REFNSIID aIID, void** aInstancePtr) \
{ \
NS_ASSERTION(aInstancePtr, \
"AggregatedQueryInterface requires a non-NULL result ptr!"); \
if ( !aInstancePtr ) \
return NS_ERROR_NULL_POINTER; \
nsISupports* foundInterface; \
if ( aIID.Equals(NS_GET_IID(nsISupports)) ) \
foundInterface = InnerObject(); \
else
#define NS_IMPL_AGGREGATED_QUERY_CYCLE_COLLECTION(_class) \
if (aIID.Equals(IsPartOfAggregated() ? \
NS_GET_IID(nsCycleCollectionParticipant) : \
NS_GET_IID(nsAggregatedCycleCollectionParticipant))) \
foundInterface = & NS_CYCLE_COLLECTION_NAME(_class); \
else
#define NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN_AGGREGATED(_class) \
NS_IMETHODIMP \
NS_CYCLE_COLLECTION_CLASSNAME(_class)::Traverse \
(void *p, \
nsCycleCollectionTraversalCallback &cb) \
{ \
nsISupports *s = static_cast<nsISupports*>(p); \
NS_ASSERTION(CheckForRightISupports(s), \
"not the nsISupports pointer we expect"); \
_class *tmp = static_cast<_class*>(Downcast(s)); \
if (!tmp->IsPartOfAggregated()) \
NS_IMPL_CYCLE_COLLECTION_DESCRIBE(_class)
#define NS_GENERIC_AGGREGATED_CONSTRUCTOR(_InstanceClass) \
static NS_METHOD \
_InstanceClass##Constructor(nsISupports *aOuter, REFNSIID aIID, \
void **aResult) \
{ \
*aResult = nsnull; \
\
NS_ENSURE_PROPER_AGGREGATION(aOuter, aIID); \
\
_InstanceClass* inst = new _InstanceClass(aOuter); \
if (!inst) { \
return NS_ERROR_OUT_OF_MEMORY; \
} \
\
nsISupports* inner = inst->InnerObject(); \
nsresult rv = inner->QueryInterface(aIID, aResult); \
if (NS_FAILED(rv)) { \
delete inst; \
} \
\
return rv; \
} \
#define NS_GENERIC_AGGREGATED_CONSTRUCTOR_INIT(_InstanceClass, _InitMethod) \
static NS_METHOD \
_InstanceClass##Constructor(nsISupports *aOuter, REFNSIID aIID, \
void **aResult) \
{ \
*aResult = nsnull; \
\
NS_ENSURE_PROPER_AGGREGATION(aOuter, aIID); \
\
_InstanceClass* inst = new _InstanceClass(aOuter); \
if (!inst) { \
return NS_ERROR_OUT_OF_MEMORY; \
} \
\
nsISupports* inner = inst->InnerObject(); \
NS_ADDREF(inner); \
nsresult rv = inst->_InitMethod(); \
if (NS_SUCCEEDED(rv)) { \
rv = inner->QueryInterface(aIID, aResult); \
} \
NS_RELEASE(inner); \
\
return rv; \
} \
#endif /* nsAgg_h___ */