1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/xpcom/base/nsAgg.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,331 @@
1.4 +/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
1.5 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.6 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.7 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.8 +
1.9 +#ifndef nsAgg_h___
1.10 +#define nsAgg_h___
1.11 +
1.12 +#include "nsISupports.h"
1.13 +#include "nsCycleCollectionParticipant.h"
1.14 +
1.15 +
1.16 +////////////////////////////////////////////////////////////////////////////////
1.17 +
1.18 +// Put NS_DECL_AGGREGATED or NS_DECL_CYCLE_COLLECTING_AGGREGATED in your class's
1.19 +// declaration.
1.20 +#define NS_DECL_AGGREGATED \
1.21 + NS_DECL_ISUPPORTS \
1.22 + NS_DECL_AGGREGATED_HELPER
1.23 +
1.24 +#define NS_DECL_CYCLE_COLLECTING_AGGREGATED \
1.25 + NS_DECL_CYCLE_COLLECTING_ISUPPORTS \
1.26 + NS_DECL_AGGREGATED_HELPER
1.27 +
1.28 +#define NS_DECL_AGGREGATED_HELPER \
1.29 +public: \
1.30 + \
1.31 + /** \
1.32 + * Returns the nsISupports pointer of the inner object (aka the \
1.33 + * aggregatee). This pointer is really only useful to the outer object \
1.34 + * (aka the aggregator), which can use it to hold on to the inner \
1.35 + * object. Anything else wants the nsISupports pointer of the outer \
1.36 + * object (gotten by QI'ing inner or outer to nsISupports). This method \
1.37 + * returns a non-addrefed pointer. \
1.38 + * @return the nsISupports pointer of the inner object \
1.39 + */ \
1.40 + nsISupports* InnerObject(void) { return &fAggregated; } \
1.41 + \
1.42 + /** \
1.43 + * Returns true if this object is part of an aggregated object. \
1.44 + */ \
1.45 + bool IsPartOfAggregated(void) { return fOuter != InnerObject(); } \
1.46 + \
1.47 +private: \
1.48 + \
1.49 + /* You must implement this operation instead of the nsISupports */ \
1.50 + /* methods. */ \
1.51 + nsresult \
1.52 + AggregatedQueryInterface(const nsIID& aIID, void** aInstancePtr); \
1.53 + \
1.54 + class Internal : public nsISupports { \
1.55 + public: \
1.56 + \
1.57 + Internal() {} \
1.58 + \
1.59 + NS_IMETHOD QueryInterface(const nsIID& aIID, void** aInstancePtr); \
1.60 + NS_IMETHOD_(MozExternalRefCountType) AddRef(void); \
1.61 + NS_IMETHOD_(MozExternalRefCountType) Release(void); \
1.62 + \
1.63 + NS_DECL_OWNINGTHREAD \
1.64 + }; \
1.65 + \
1.66 + friend class Internal; \
1.67 + \
1.68 + nsISupports* fOuter; \
1.69 + Internal fAggregated; \
1.70 + \
1.71 +public: \
1.72 +
1.73 +#define NS_DECL_AGGREGATED_CYCLE_COLLECTION_CLASS(_class) \
1.74 +class NS_CYCLE_COLLECTION_INNERCLASS \
1.75 + : public nsXPCOMCycleCollectionParticipant \
1.76 +{ \
1.77 +public: \
1.78 + NS_IMETHOD_(void) Unlink(void *p); \
1.79 + NS_IMETHOD Traverse(void *p, nsCycleCollectionTraversalCallback &cb); \
1.80 + NS_IMETHOD_(void) DeleteCycleCollectable(void* p) \
1.81 + { \
1.82 + NS_CYCLE_COLLECTION_CLASSNAME(_class):: \
1.83 + Downcast(static_cast<nsISupports*>(p))->DeleteCycleCollectable(); \
1.84 + } \
1.85 + static _class* Downcast(nsISupports* s) \
1.86 + { \
1.87 + return (_class*)((char*)(s) - offsetof(_class, fAggregated)); \
1.88 + } \
1.89 + static nsISupports* Upcast(_class *p) \
1.90 + { \
1.91 + return p->InnerObject(); \
1.92 + } \
1.93 + static nsXPCOMCycleCollectionParticipant* GetParticipant() \
1.94 + { \
1.95 + return &_class::NS_CYCLE_COLLECTION_INNERNAME; \
1.96 + } \
1.97 +}; \
1.98 +NS_CHECK_FOR_RIGHT_PARTICIPANT_IMPL(_class); \
1.99 +static NS_CYCLE_COLLECTION_INNERCLASS NS_CYCLE_COLLECTION_INNERNAME;
1.100 +
1.101 +// Put this in your class's constructor:
1.102 +#define NS_INIT_AGGREGATED(outer) \
1.103 + PR_BEGIN_MACRO \
1.104 + fOuter = outer ? outer : &fAggregated; \
1.105 + PR_END_MACRO
1.106 +
1.107 +
1.108 +// Put this in your class's implementation file:
1.109 +#define NS_IMPL_AGGREGATED(_class) \
1.110 + \
1.111 +NS_IMPL_AGGREGATED_HELPER(_class) \
1.112 + \
1.113 +NS_IMETHODIMP_(MozExternalRefCountType) \
1.114 +_class::Internal::AddRef(void) \
1.115 +{ \
1.116 + _class* agg = (_class*)((char*)(this) - offsetof(_class, fAggregated)); \
1.117 + MOZ_ASSERT(int32_t(agg->mRefCnt) >= 0, "illegal refcnt"); \
1.118 + NS_ASSERT_OWNINGTHREAD(_class); \
1.119 + ++agg->mRefCnt; \
1.120 + NS_LOG_ADDREF(this, agg->mRefCnt, #_class, sizeof(*this)); \
1.121 + return agg->mRefCnt; \
1.122 +} \
1.123 + \
1.124 +NS_IMETHODIMP_(MozExternalRefCountType) \
1.125 +_class::Internal::Release(void) \
1.126 +{ \
1.127 + _class* agg = (_class*)((char*)(this) - offsetof(_class, fAggregated)); \
1.128 + MOZ_ASSERT(int32_t(agg->mRefCnt) > 0, "dup release"); \
1.129 + NS_ASSERT_OWNINGTHREAD(_class); \
1.130 + --agg->mRefCnt; \
1.131 + NS_LOG_RELEASE(this, agg->mRefCnt, #_class); \
1.132 + if (agg->mRefCnt == 0) { \
1.133 + agg->mRefCnt = 1; /* stabilize */ \
1.134 + delete agg; \
1.135 + return 0; \
1.136 + } \
1.137 + return agg->mRefCnt; \
1.138 +} \
1.139 +
1.140 +#define NS_IMPL_CYCLE_COLLECTING_AGGREGATED(_class) \
1.141 + \
1.142 +NS_IMPL_AGGREGATED_HELPER(_class) \
1.143 + \
1.144 +NS_IMETHODIMP_(MozExternalRefCountType) \
1.145 +_class::Internal::AddRef(void) \
1.146 +{ \
1.147 + _class* agg = NS_CYCLE_COLLECTION_CLASSNAME(_class)::Downcast(this); \
1.148 + MOZ_ASSERT(int32_t(agg->mRefCnt) >= 0, "illegal refcnt"); \
1.149 + NS_ASSERT_OWNINGTHREAD_AGGREGATE(agg, _class); \
1.150 + nsrefcnt count = agg->mRefCnt.incr(this); \
1.151 + NS_LOG_ADDREF(this, count, #_class, sizeof(*agg)); \
1.152 + return count; \
1.153 +} \
1.154 +NS_IMETHODIMP_(MozExternalRefCountType) \
1.155 +_class::Internal::Release(void) \
1.156 +{ \
1.157 + _class* agg = NS_CYCLE_COLLECTION_CLASSNAME(_class)::Downcast(this); \
1.158 + MOZ_ASSERT(int32_t(agg->mRefCnt) > 0, "dup release"); \
1.159 + NS_ASSERT_OWNINGTHREAD_AGGREGATE(agg, _class); \
1.160 + nsrefcnt count = agg->mRefCnt.decr(this); \
1.161 + NS_LOG_RELEASE(this, count, #_class); \
1.162 + return count; \
1.163 +} \
1.164 +NS_IMETHODIMP_(void) \
1.165 +_class::DeleteCycleCollectable(void) \
1.166 +{ \
1.167 + delete this; \
1.168 +}
1.169 +
1.170 +#define NS_IMPL_AGGREGATED_HELPER(_class) \
1.171 +NS_IMETHODIMP \
1.172 +_class::QueryInterface(const nsIID& aIID, void** aInstancePtr) \
1.173 +{ \
1.174 + return fOuter->QueryInterface(aIID, aInstancePtr); \
1.175 +} \
1.176 + \
1.177 +NS_IMETHODIMP_(MozExternalRefCountType) \
1.178 +_class::AddRef(void) \
1.179 +{ \
1.180 + return fOuter->AddRef(); \
1.181 +} \
1.182 + \
1.183 +NS_IMETHODIMP_(MozExternalRefCountType) \
1.184 +_class::Release(void) \
1.185 +{ \
1.186 + return fOuter->Release(); \
1.187 +} \
1.188 + \
1.189 +NS_IMETHODIMP \
1.190 +_class::Internal::QueryInterface(const nsIID& aIID, void** aInstancePtr) \
1.191 +{ \
1.192 + _class* agg = (_class*)((char*)(this) - offsetof(_class, fAggregated)); \
1.193 + return agg->AggregatedQueryInterface(aIID, aInstancePtr); \
1.194 +} \
1.195 +
1.196 +/**
1.197 + * To make aggregated objects participate in cycle collection we need to enable
1.198 + * the outer object (aggregator) to traverse/unlink the objects held by the
1.199 + * inner object (the aggregatee). We can't just make the inner object QI'able to
1.200 + * NS_CYCLECOLLECTIONPARTICIPANT_IID, we don't want to return the inner object's
1.201 + * nsCycleCollectionParticipant for the outer object (which will happen if the
1.202 + * outer object doesn't participate in cycle collection itself).
1.203 + * NS_AGGREGATED_CYCLECOLLECTIONPARTICIPANT_IID enables the outer object to get
1.204 + * the inner objects nsCycleCollectionParticipant.
1.205 + *
1.206 + * There are three cases:
1.207 + * - No aggregation
1.208 + * QI'ing to NS_CYCLECOLLECTIONPARTICIPANT_IID will return the inner
1.209 + * object's nsCycleCollectionParticipant.
1.210 + *
1.211 + * - Aggregation and outer object does not participate in cycle collection
1.212 + * QI'ing to NS_CYCLECOLLECTIONPARTICIPANT_IID will not return anything.
1.213 + *
1.214 + * - Aggregation and outer object does participate in cycle collection
1.215 + * QI'ing to NS_CYCLECOLLECTIONPARTICIPANT_IID will return the outer
1.216 + * object's nsCycleCollectionParticipant. The outer object's
1.217 + * nsCycleCollectionParticipant can then QI the inner object to
1.218 + * NS_AGGREGATED_CYCLECOLLECTIONPARTICIPANT_IID to get the inner object's
1.219 + * nsCycleCollectionParticipant, which it can use to traverse/unlink the
1.220 + * objects reachable from the inner object.
1.221 + */
1.222 +#define NS_AGGREGATED_CYCLECOLLECTIONPARTICIPANT_IID \
1.223 +{ \
1.224 + 0x32889b7e, \
1.225 + 0xe4fe, \
1.226 + 0x43f4, \
1.227 + { 0x85, 0x31, 0xb5, 0x28, 0x23, 0xa2, 0xe9, 0xfc } \
1.228 +}
1.229 +
1.230 +/**
1.231 + * Just holds the IID so NS_GET_IID works.
1.232 + */
1.233 +class nsAggregatedCycleCollectionParticipant
1.234 +{
1.235 +public:
1.236 + NS_DECLARE_STATIC_IID_ACCESSOR(NS_AGGREGATED_CYCLECOLLECTIONPARTICIPANT_IID)
1.237 +};
1.238 +
1.239 +NS_DEFINE_STATIC_IID_ACCESSOR(nsAggregatedCycleCollectionParticipant,
1.240 + NS_AGGREGATED_CYCLECOLLECTIONPARTICIPANT_IID)
1.241 +
1.242 +// for use with QI macros in nsISupportsUtils.h:
1.243 +
1.244 +#define NS_INTERFACE_MAP_BEGIN_AGGREGATED(_class) \
1.245 + NS_IMPL_AGGREGATED_QUERY_HEAD(_class)
1.246 +
1.247 +#define NS_INTERFACE_MAP_ENTRY_CYCLE_COLLECTION_AGGREGATED(_class) \
1.248 + NS_IMPL_QUERY_CYCLE_COLLECTION(_class)
1.249 +
1.250 +#define NS_INTERFACE_MAP_ENTRIES_CYCLE_COLLECTION_AGGREGATED(_class) \
1.251 + NS_INTERFACE_MAP_ENTRY_CYCLE_COLLECTION_AGGREGATED(_class) \
1.252 + NS_INTERFACE_MAP_ENTRY_CYCLE_COLLECTION_ISUPPORTS(_class)
1.253 +
1.254 +#define NS_IMPL_AGGREGATED_QUERY_HEAD(_class) \
1.255 +nsresult \
1.256 +_class::AggregatedQueryInterface(REFNSIID aIID, void** aInstancePtr) \
1.257 +{ \
1.258 + NS_ASSERTION(aInstancePtr, \
1.259 + "AggregatedQueryInterface requires a non-NULL result ptr!"); \
1.260 + if ( !aInstancePtr ) \
1.261 + return NS_ERROR_NULL_POINTER; \
1.262 + nsISupports* foundInterface; \
1.263 + if ( aIID.Equals(NS_GET_IID(nsISupports)) ) \
1.264 + foundInterface = InnerObject(); \
1.265 + else
1.266 +
1.267 +#define NS_IMPL_AGGREGATED_QUERY_CYCLE_COLLECTION(_class) \
1.268 + if (aIID.Equals(IsPartOfAggregated() ? \
1.269 + NS_GET_IID(nsCycleCollectionParticipant) : \
1.270 + NS_GET_IID(nsAggregatedCycleCollectionParticipant))) \
1.271 + foundInterface = NS_CYCLE_COLLECTION_PARTICIPANT(_class); \
1.272 + else
1.273 +
1.274 +#define NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN_AGGREGATED(_class) \
1.275 + NS_IMETHODIMP \
1.276 + NS_CYCLE_COLLECTION_CLASSNAME(_class)::Traverse \
1.277 + (void *p, nsCycleCollectionTraversalCallback &cb) \
1.278 + { \
1.279 + nsISupports *s = static_cast<nsISupports*>(p); \
1.280 + MOZ_ASSERT(CheckForRightISupports(s), \
1.281 + "not the nsISupports pointer we expect"); \
1.282 + _class *tmp = static_cast<_class*>(Downcast(s)); \
1.283 + if (!tmp->IsPartOfAggregated()) \
1.284 + NS_IMPL_CYCLE_COLLECTION_DESCRIBE(_class, tmp->mRefCnt.get())
1.285 +
1.286 +#define NS_GENERIC_AGGREGATED_CONSTRUCTOR(_InstanceClass) \
1.287 +static nsresult \
1.288 +_InstanceClass##Constructor(nsISupports *aOuter, REFNSIID aIID, \
1.289 + void **aResult) \
1.290 +{ \
1.291 + *aResult = nullptr; \
1.292 + if (NS_WARN_IF(aOuter && !aIID.Equals(NS_GET_IID(nsISupports)))) \
1.293 + return NS_ERROR_INVALID_ARG; \
1.294 + \
1.295 + _InstanceClass* inst = new _InstanceClass(aOuter); \
1.296 + if (!inst) { \
1.297 + return NS_ERROR_OUT_OF_MEMORY; \
1.298 + } \
1.299 + \
1.300 + nsISupports* inner = inst->InnerObject(); \
1.301 + nsresult rv = inner->QueryInterface(aIID, aResult); \
1.302 + if (NS_FAILED(rv)) { \
1.303 + delete inst; \
1.304 + } \
1.305 + \
1.306 + return rv; \
1.307 +} \
1.308 +
1.309 +#define NS_GENERIC_AGGREGATED_CONSTRUCTOR_INIT(_InstanceClass, _InitMethod) \
1.310 +static nsresult \
1.311 +_InstanceClass##Constructor(nsISupports *aOuter, REFNSIID aIID, \
1.312 + void **aResult) \
1.313 +{ \
1.314 + *aResult = nullptr; \
1.315 + if (NS_WARN_IF(aOuter && !aIID.Equals(NS_GET_IID(nsISupports)))) \
1.316 + return NS_ERROR_INVALID_ARG; \
1.317 + \
1.318 + _InstanceClass* inst = new _InstanceClass(aOuter); \
1.319 + if (!inst) { \
1.320 + return NS_ERROR_OUT_OF_MEMORY; \
1.321 + } \
1.322 + \
1.323 + nsISupports* inner = inst->InnerObject(); \
1.324 + NS_ADDREF(inner); \
1.325 + nsresult rv = inst->_InitMethod(); \
1.326 + if (NS_SUCCEEDED(rv)) { \
1.327 + rv = inner->QueryInterface(aIID, aResult); \
1.328 + } \
1.329 + NS_RELEASE(inner); \
1.330 + \
1.331 + return rv; \
1.332 +} \
1.333 +
1.334 +#endif /* nsAgg_h___ */
