/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ /* vim: set ts=8 sts=2 et sw=2 tw=80: */ /* This Source Code Form is subject to the terms of the Mozilla Public * License, v. 2.0. If a copy of the MPL was not distributed with this * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ #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 true if this object is part of an aggregated object. \ */ \ bool 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_(MozExternalRefCountType) AddRef(void); \ NS_IMETHOD_(MozExternalRefCountType) Release(void); \ \ NS_DECL_OWNINGTHREAD \ }; \ \ friend class Internal; \ \ nsISupports* MOZ_UNSAFE_REF("fOuter can either point to fAggregated " \ "or to an outer object, and the safety " \ "of this reference depends on the exact " \ "lifetime semantics of the AddRef/Release " \ "functions created by these macros.") \ fOuter; \ Internal fAggregated; \ \ public: \ #define NS_DECL_AGGREGATED_CYCLE_COLLECTION_CLASS(_class) \ class NS_CYCLE_COLLECTION_INNERCLASS \ : public nsXPCOMCycleCollectionParticipant \ { \ public: \ NS_IMETHOD_(void) Unlink(void *p) override; \ NS_IMETHOD Traverse(void *p, nsCycleCollectionTraversalCallback &cb) \ override; \ NS_DECL_CYCLE_COLLECTION_CLASS_NAME_METHOD(_class) \ NS_IMETHOD_(void) DeleteCycleCollectable(void* p) override \ { \ NS_CYCLE_COLLECTION_CLASSNAME(_class):: \ Downcast(static_cast<nsISupports*>(p))->DeleteCycleCollectable(); \ } \ static _class* Downcast(nsISupports* s) \ { \ return (_class*)((char*)(s) - offsetof(_class, fAggregated)); \ } \ static nsISupports* Upcast(_class *p) \ { \ return p->InnerObject(); \ } \ static nsXPCOMCycleCollectionParticipant* GetParticipant() \ { \ return &_class::NS_CYCLE_COLLECTION_INNERNAME; \ } \ }; \ NS_CHECK_FOR_RIGHT_PARTICIPANT_IMPL(_class); \ static NS_CYCLE_COLLECTION_INNERCLASS NS_CYCLE_COLLECTION_INNERNAME; // 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_(MozExternalRefCountType) \ _class::Internal::AddRef(void) \ { \ _class* agg = (_class*)((char*)(this) - offsetof(_class, fAggregated)); \ MOZ_ASSERT(int32_t(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_(MozExternalRefCountType) \ _class::Internal::Release(void) \ { \ _class* agg = (_class*)((char*)(this) - offsetof(_class, fAggregated)); \ MOZ_ASSERT(int32_t(agg->mRefCnt) > 0, "dup release"); \ NS_ASSERT_OWNINGTHREAD(_class); \ --agg->mRefCnt; \ NS_LOG_RELEASE(this, agg->mRefCnt, #_class); \ if (agg->mRefCnt == 0) { \ agg->mRefCnt = 1; /* stabilize */ \ delete agg; \ return 0; \ } \ return agg->mRefCnt; \ } \ #define NS_IMPL_CYCLE_COLLECTING_AGGREGATED(_class) \ \ NS_IMPL_AGGREGATED_HELPER(_class) \ \ NS_IMETHODIMP_(MozExternalRefCountType) \ _class::Internal::AddRef(void) \ { \ _class* agg = NS_CYCLE_COLLECTION_CLASSNAME(_class)::Downcast(this); \ MOZ_ASSERT(int32_t(agg->mRefCnt) >= 0, "illegal refcnt"); \ NS_ASSERT_OWNINGTHREAD_AGGREGATE(agg, _class); \ nsrefcnt count = agg->mRefCnt.incr(this); \ NS_LOG_ADDREF(this, count, #_class, sizeof(*agg)); \ return count; \ } \ NS_IMETHODIMP_(MozExternalRefCountType) \ _class::Internal::Release(void) \ { \ _class* agg = NS_CYCLE_COLLECTION_CLASSNAME(_class)::Downcast(this); \ MOZ_ASSERT(int32_t(agg->mRefCnt) > 0, "dup release"); \ NS_ASSERT_OWNINGTHREAD_AGGREGATE(agg, _class); \ nsrefcnt count = agg->mRefCnt.decr(this); \ NS_LOG_RELEASE(this, count, #_class); \ return count; \ } \ NS_IMETHODIMP_(void) \ _class::DeleteCycleCollectable(void) \ { \ delete this; \ } #define NS_IMPL_AGGREGATED_HELPER(_class) \ NS_IMETHODIMP \ _class::QueryInterface(const nsIID& aIID, void** aInstancePtr) \ { \ return fOuter->QueryInterface(aIID, aInstancePtr); \ } \ \ NS_IMETHODIMP_(MozExternalRefCountType) \ _class::AddRef(void) \ { \ return fOuter->AddRef(); \ } \ \ NS_IMETHODIMP_(MozExternalRefCountType) \ _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_PARTICIPANT(_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); \ MOZ_ASSERT(CheckForRightISupports(s), \ "not the nsISupports pointer we expect"); \ _class *tmp = static_cast<_class*>(Downcast(s)); \ if (!tmp->IsPartOfAggregated()) \ NS_IMPL_CYCLE_COLLECTION_DESCRIBE(_class, tmp->mRefCnt.get()) #define NS_GENERIC_AGGREGATED_CONSTRUCTOR(_InstanceClass) \ static nsresult \ _InstanceClass##Constructor(nsISupports *aOuter, REFNSIID aIID, \ void **aResult) \ { \ *aResult = nullptr; \ if (NS_WARN_IF(aOuter && !aIID.Equals(NS_GET_IID(nsISupports)))) \ return NS_ERROR_INVALID_ARG; \ \ RefPtr<_InstanceClass> inst = new _InstanceClass(aOuter); \ if (!inst) { \ return NS_ERROR_OUT_OF_MEMORY; \ } \ \ nsISupports* inner = inst->InnerObject(); \ nsresult rv = inner->QueryInterface(aIID, aResult); \ \ return rv; \ } \ #define NS_GENERIC_AGGREGATED_CONSTRUCTOR_INIT(_InstanceClass, _InitMethod) \ static nsresult \ _InstanceClass##Constructor(nsISupports *aOuter, REFNSIID aIID, \ void **aResult) \ { \ *aResult = nullptr; \ if (NS_WARN_IF(aOuter && !aIID.Equals(NS_GET_IID(nsISupports)))) \ return NS_ERROR_INVALID_ARG; \ \ RefPtr<_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___ */