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nsAgg.h
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00037 
00038 #ifndef nsAgg_h___
00039 #define nsAgg_h___
00040 
00041 #include "nsISupports.h"
00042 
00043 
00045 
00046 // Put this in your class's declaration:
00047 #define NS_DECL_AGGREGATED                                                  \
00048     NS_DECL_ISUPPORTS                                                       \
00049                                                                             \
00050 public:                                                                     \
00051                                                                             \
00052     /* You must implement this operation instead of the nsISupports */      \
00053     /* methods if you inherit from nsAggregated. */                         \
00054     NS_IMETHOD                                                              \
00055     AggregatedQueryInterface(const nsIID& aIID, void** aInstancePtr);       \
00056                                                                             \
00057 protected:                                                                  \
00058                                                                             \
00059     class Internal : public nsISupports {                                   \
00060     public:                                                                 \
00061                                                                             \
00062         Internal() {}                                                       \
00063                                                                             \
00064         NS_IMETHOD QueryInterface(const nsIID& aIID,                        \
00065                                         void** aInstancePtr);               \
00066         NS_IMETHOD_(nsrefcnt) AddRef(void);                                 \
00067         NS_IMETHOD_(nsrefcnt) Release(void);                                \
00068                                                                             \
00069     };                                                                      \
00070                                                                             \
00071     friend class Internal;                                                  \
00072                                                                             \
00073     nsISupports*        fOuter;                                             \
00074     Internal            fAggregated;                                        \
00075                                                                             \
00076     nsISupports* GetInner(void) { return &fAggregated; }                    \
00077                                                                             \
00078 public:                                                                     \
00079 
00080 
00081 // Put this in your class's constructor:
00082 #define NS_INIT_AGGREGATED(outer)                                           \
00083   PR_BEGIN_MACRO                                                            \
00084     fOuter = outer ? outer : &fAggregated;                                  \
00085   PR_END_MACRO
00086 
00087 
00088 // Put this in your class's implementation file:
00089 #define NS_IMPL_AGGREGATED(_class)                                          \
00090 NS_IMETHODIMP                                                               \
00091 _class::QueryInterface(const nsIID& aIID, void** aInstancePtr)              \
00092 {                                                                           \
00093     return fOuter->QueryInterface(aIID, aInstancePtr);                      \
00094 }                                                                           \
00095                                                                             \
00096 NS_IMETHODIMP_(nsrefcnt)                                                    \
00097 _class::AddRef(void)                                                        \
00098 {                                                                           \
00099     return fOuter->AddRef();                                                \
00100 }                                                                           \
00101                                                                             \
00102 NS_IMETHODIMP_(nsrefcnt)                                                    \
00103 _class::Release(void)                                                       \
00104 {                                                                           \
00105     return fOuter->Release();                                               \
00106 }                                                                           \
00107                                                                             \
00108 NS_IMETHODIMP                                                               \
00109 _class::Internal::QueryInterface(const nsIID& aIID, void** aInstancePtr)    \
00110 {                                                                           \
00111     _class* agg = (_class*)((char*)(this) - offsetof(_class, fAggregated)); \
00112     return agg->AggregatedQueryInterface(aIID, aInstancePtr);               \
00113 }                                                                           \
00114                                                                             \
00115 NS_IMETHODIMP_(nsrefcnt)                                                    \
00116 _class::Internal::AddRef(void)                                              \
00117 {                                                                           \
00118     _class* agg = (_class*)((char*)(this) - offsetof(_class, fAggregated)); \
00119     NS_PRECONDITION(PRInt32(agg->mRefCnt) >= 0, "illegal refcnt");          \
00120     ++agg->mRefCnt;                                                         \
00121     NS_LOG_ADDREF(this, agg->mRefCnt, #_class, sizeof(*this));              \
00122     return agg->mRefCnt;                                                    \
00123 }                                                                           \
00124                                                                             \
00125 NS_IMETHODIMP_(nsrefcnt)                                                    \
00126 _class::Internal::Release(void)                                             \
00127 {                                                                           \
00128     _class* agg = (_class*)((char*)(this) - offsetof(_class, fAggregated)); \
00129     NS_PRECONDITION(0 != agg->mRefCnt, "dup release");                      \
00130     --agg->mRefCnt;                                                         \
00131     NS_LOG_RELEASE(this, agg->mRefCnt, #_class);                            \
00132     if (agg->mRefCnt == 0) {                                                \
00133         agg->mRefCnt = 1; /* stabilize */                                   \
00134         NS_DELETEXPCOM(agg);                                                \
00135         return 0;                                                           \
00136     }                                                                       \
00137     return agg->mRefCnt;                                                    \
00138 }                                                                           \
00139 
00140 // for use with QI macros in nsISupportsUtils.h:
00141 
00142 #define NS_INTERFACE_MAP_BEGIN_AGGREGATED(_class)                           \
00143   NS_IMPL_AGGREGATED_QUERY_HEAD(_class)
00144 
00145 #define NS_IMPL_AGGREGATED_QUERY_HEAD(_class)                               \
00146 NS_IMETHODIMP                                                               \
00147 _class::AggregatedQueryInterface(REFNSIID aIID, void** aInstancePtr)        \
00148 {                                                                           \
00149   NS_ASSERTION(aInstancePtr,                                                \
00150                "AggregatedQueryInterface requires a non-NULL result ptr!"); \
00151   if ( !aInstancePtr )                                                      \
00152     return NS_ERROR_NULL_POINTER;                                           \
00153   nsISupports* foundInterface;
00154 
00155 #endif /* nsAgg_h___ */