/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ /* * 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 nsCOMPtr_h___ #define nsCOMPtr_h___ // Wrapping includes can speed up compiles (see "Large Scale C++ Software Design") #ifndef nsDebug_h___ #include "nsDebug.h" // for |NS_PRECONDITION| #endif #ifndef nsISupports_h___ #include "nsISupports.h" // for |nsresult|, |NS_ADDREF|, et al #endif #ifndef __gen_nsIWeakReference_h__ #include "nsIWeakReference.h" // for |nsIWeakReference| #endif /* Public things defined in this file: T* rawTptr; class nsCOMPtr nsCOMPtr smartTptr; do_QueryInterface( nsISupports* ) smartTptr = do_QueryInterface(other_ptr); do_QueryInterface( nsISupports*, nsresult* ) smartTptr = do_QueryInterface(other_ptr, &status); dont_QueryInterface( T* ) smartTptr = dont_QueryInterface(rawTptr); getter_AddRefs( nsCOMPtr& ) rv = SomeGetter( getter_AddRefs(smartTptr) ); getter_AddRefs( T* ) smartTptr = getter_AddRefs( SomeGetter() ); dont_AddRef( T* ) smartTptr = dont_AddRef(rawTptr); do_QueryReferent( nsIWeakReference* ) do_QueryReferent( nsIWeakReference*, nsresult* ) SameCOMIdentity( nsISupports*, nsISupports* ) if ( SameCOMIdentity(rawTptr, rawUptr) ) ... smartTptr == smartUptr smartTptr != smartUptr smartTptr == rawUptr smartTptr != rawUptr rawTptr == smartUptr rawTptr != smartUptr smartTptr == 0 smartTptr != 0 0 == smartTptr // Don't use this form 0 != smartTptr // some compilers just don't like it Anytime you are comparing |nsCOMPtr|s with raw pointers, it is always safe to use the |.get()| notation. Some compilers have some ambiguity issues, and |.get()| will resolve them. Try to write you comparisons like this if ( smartTptr ) ... if ( !smartTptr ) ... if ( smartTptr1 == smartTptr2 ) ... if ( smartTptr.get() != rawTptr ) ... */ /* Having problems? See the User Manual at: */ /* TO DO... + Improve internal documentation + mention *& + do_QueryInterface */ /* WARNING: This file defines several macros for internal use only. These macros begin with the prefix |NSCAP_|. Do not use these macros in your own code. They are for internal use only for cross-platform compatibility, and are subject to change without notice. */ /* Set up some |#define|s to turn off a couple of troublesome C++ features. Interestingly, none of the compilers barf on template stuff. These are set up automatically by the autoconf system for all Unixes. (Temporarily, I hope) I have to define them myself for Mac and Windows. */ // under Metrowerks (Mac), we don't have autoconf yet #ifdef __MWERKS__ #define HAVE_CPP_USING #define HAVE_CPP_EXPLICIT #define HAVE_CPP_NEW_CASTS #define HAVE_CPP_BOOL #endif // under VC++ (Windows), we don't have autoconf yet #ifdef _MSC_VER #define HAVE_CPP_EXPLICIT #define HAVE_CPP_USING #define HAVE_CPP_NEW_CASTS #if (_MSC_VER<1100) // before 5.0, VC++ couldn't handle explicit #undef HAVE_CPP_EXPLICIT #elif (_MSC_VER==1100) // VC++5.0 has an internal compiler error (sometimes) without this #undef HAVE_CPP_USING #endif #define NSCAP_FEATURE_INLINE_STARTASSIGNMENT // under VC++, we win by inlining StartAssignment #endif #define NSCAP_FEATURE_FACTOR_DESTRUCTOR #ifdef NS_DEBUG #define NSCAP_FEATURE_TEST_DONTQUERY_CASES #define NSCAP_FEATURE_DEBUG_PTR_TYPES #endif /* |...TEST_DONTQUERY_CASES| and |...DEBUG_PTR_TYPES| introduce some code that is problematic on a select few of our platforms, e.g., QNX. Therefore, I'm providing a mechanism by which these features can be explicitly disabled from the command-line. */ #ifdef NSCAP_DISABLE_TEST_DONTQUERY_CASES #undef NSCAP_FEATURE_TEST_DONTQUERY_CASES #endif #if defined(NSCAP_DISABLE_DEBUG_PTR_TYPES) || !defined(NS_DEBUG) #undef NSCAP_FEATURE_DEBUG_PTR_TYPES #endif #ifdef NSCAP_FEATURE_DEBUG_PTR_TYPES #undef NSCAP_FEATURE_FACTOR_DESTRUCTOR #endif /* If the compiler doesn't support |explicit|, we'll just make it go away, trusting that the builds under compilers that do have it will keep us on the straight and narrow. */ #ifndef HAVE_CPP_EXPLICIT #define explicit #endif #ifdef HAVE_CPP_BOOL typedef bool NSCAP_BOOL; #else typedef PRBool NSCAP_BOOL; #endif #ifdef HAVE_CPP_NEW_CASTS #define NSCAP_STATIC_CAST(T,x) static_cast(x) #define NSCAP_REINTERPRET_CAST(T,x) reinterpret_cast(x) #else #define NSCAP_STATIC_CAST(T,x) ((T)(x)) #define NSCAP_REINTERPRET_CAST(T,x) ((T)(x)) #endif #ifdef NSCAP_FEATURE_DEBUG_MACROS #define NSCAP_ADDREF(ptr) NS_ADDREF(ptr) #define NSCAP_RELEASE(ptr) NS_RELEASE(ptr) #else #define NSCAP_ADDREF(ptr) (ptr)->AddRef() #define NSCAP_RELEASE(ptr) (ptr)->Release() #endif /* WARNING: VC++4.2 is very picky. To compile under VC++4.2, the classes must be defined in an order that satisfies: nsDerivedSafe < nsCOMPtr nsDontAddRef < nsCOMPtr nsCOMPtr < nsGetterAddRefs The other compilers probably won't complain, so please don't reorder these classes, on pain of breaking 4.2 compatibility. */ template class nsDerivedSafe : public T /* No client should ever see or have to type the name of this class. It is the artifact that makes it a compile-time error to call |AddRef| and |Release| on a |nsCOMPtr|. DO NOT USE THIS TYPE DIRECTLY IN YOUR CODE. See |nsCOMPtr::operator->|, |nsCOMPtr::operator*|, et al. This type should be a nested class inside |nsCOMPtr|. */ { private: #ifdef HAVE_CPP_USING using T::AddRef; using T::Release; #else NS_IMETHOD_(nsrefcnt) AddRef(void); NS_IMETHOD_(nsrefcnt) Release(void); #endif void operator delete( void*, size_t ); // NOT TO BE IMPLEMENTED // declaring |operator delete| private makes calling delete on an interface pointer a compile error nsDerivedSafe& operator=( const T& ); // NOT TO BE IMPLEMENTED // you may not call |operator=()| through a dereferenced |nsCOMPtr|, because you'd get the wrong one /* Compiler warnings and errors: nsDerivedSafe operator=() hides inherited operator=(). If you see that, that means somebody checked in a (XP)COM interface class that declares an |operator=()|, and that's _bad_. So bad, in fact, that this declaration exists explicitly to stop people from doing it. */ }; #if !defined(HAVE_CPP_USING) && defined(NEED_CPP_UNUSED_IMPLEMENTATIONS) template nsrefcnt nsDerivedSafe::AddRef() { return 0; } template nsrefcnt nsDerivedSafe::Release() { return 0; } #endif template struct nsDontQueryInterface /* ... DO NOT USE THIS TYPE DIRECTLY IN YOUR CODE. Use |dont_QueryInterface()| instead. This type should be a nested class inside |nsCOMPtr|. */ { explicit nsDontQueryInterface( T* aRawPtr ) : mRawPtr(aRawPtr) { // nothing else to do here } T* mRawPtr; }; template inline const nsDontQueryInterface dont_QueryInterface( T* aRawPtr ) { return nsDontQueryInterface(aRawPtr); } template struct nsCOMPtrQueryRequest { T* mRawPtr; nsresult* mErrorPtr; explicit nsCOMPtrQueryRequest( T* aRawPtr, nsresult* error = 0 ) : mRawPtr(aRawPtr), mErrorPtr(error) { // nothing else to do here } }; typedef nsCOMPtrQueryRequest nsQueryInterface; typedef nsCOMPtrQueryRequest nsQueryReferent; inline const nsQueryInterface do_QueryInterface( nsISupports* aRawPtr, nsresult* error = 0 ) { return nsQueryInterface(aRawPtr, error); } inline const nsQueryReferent do_QueryReferent( nsIWeakReference* aRawPtr, nsresult* error = 0 ) { return nsQueryReferent(aRawPtr, error); } /** * |null_nsCOMPtr| is deprecated. Please use the value |0| instead. */ #define null_nsCOMPtr() (0) template struct nsDontAddRef /* ...cooperates with |nsCOMPtr| to allow you to assign in a pointer _without_ |AddRef|ing it. You would rarely use this directly, but rather through the machinery of |getter_AddRefs| in the argument list to functions that |AddRef| their results before returning them to the caller. DO NOT USE THIS TYPE DIRECTLY IN YOUR CODE. Use |getter_AddRefs()| or |dont_AddRef()| instead. See also |getter_AddRefs()|, |dont_AddRef()|, and |class nsGetterAddRefs|. This type should be a nested class inside |nsCOMPtr|. */ { explicit nsDontAddRef( T* aRawPtr ) : mRawPtr(aRawPtr) { // nothing else to do here } T* mRawPtr; }; template inline const nsDontAddRef getter_AddRefs( T* aRawPtr ) /* ...makes typing easier, because it deduces the template type, e.g., you write |dont_AddRef(fooP)| instead of |nsDontAddRef(fooP)|. */ { return nsDontAddRef(aRawPtr); } template inline const nsDontAddRef dont_AddRef( T* aRawPtr ) { return nsDontAddRef(aRawPtr); } class nsCOMPtr_base /* ...factors implementation for all template versions of |nsCOMPtr|. This should really be an |nsCOMPtr|, but this wouldn't work because unlike the Here's the way people normally do things like this template class Foo { ... }; template <> class Foo { ... }; template class Foo : private Foo { ... }; */ { public: nsCOMPtr_base( nsISupports* rawPtr = 0 ) : mRawPtr(rawPtr) { // nothing else to do here } #ifdef NSCAP_FEATURE_FACTOR_DESTRUCTOR NS_EXPORT ~nsCOMPtr_base(); #endif NS_EXPORT void assign_with_AddRef( nsISupports* ); NS_EXPORT void assign_with_QueryInterface( nsISupports*, const nsIID&, nsresult* ); NS_EXPORT void assign_with_QueryReferent( nsIWeakReference*, const nsIID&, nsresult* ); NS_EXPORT void** begin_assignment(); protected: nsISupports* mRawPtr; }; // template class nsGetterAddRefs; template class nsCOMPtr #ifndef NSCAP_FEATURE_DEBUG_PTR_TYPES : private nsCOMPtr_base #endif { #ifdef NSCAP_FEATURE_DEBUG_PTR_TYPES private: void assign_with_AddRef( nsISupports* ); void assign_with_QueryInterface( nsISupports*, const nsIID&, nsresult* ); void assign_with_QueryReferent( nsIWeakReference*, const nsIID&, nsresult* ); void** begin_assignment(); private: T* mRawPtr; #define NSCAP_CTOR_BASE(x) mRawPtr(x) #else #define NSCAP_CTOR_BASE(x) nsCOMPtr_base(x) #endif public: typedef T element_type; #ifndef NSCAP_FEATURE_FACTOR_DESTRUCTOR ~nsCOMPtr() { if ( mRawPtr ) NSCAP_RELEASE(mRawPtr); } #endif nsCOMPtr() : NSCAP_CTOR_BASE(0) { // nothing else to do here } nsCOMPtr( const nsQueryInterface& aSmartPtr ) : NSCAP_CTOR_BASE(0) { assign_with_QueryInterface(aSmartPtr.mRawPtr, nsCOMTypeInfo::GetIID(), aSmartPtr.mErrorPtr); } nsCOMPtr( const nsQueryReferent& aSmartPtr ) : NSCAP_CTOR_BASE(0) { assign_with_QueryReferent(aSmartPtr.mRawPtr, nsCOMTypeInfo::GetIID(), aSmartPtr.mErrorPtr); } #ifdef NSCAP_FEATURE_TEST_DONTQUERY_CASES void Assert_NoQueryNeeded() { if ( mRawPtr ) { T* query_result = 0; nsresult status = CallQueryInterface(mRawPtr, &query_result); NS_ASSERTION(query_result == mRawPtr, "QueryInterface needed"); if ( NS_SUCCEEDED(status) ) NSCAP_RELEASE(query_result); } } #define NSCAP_ASSERT_NO_QUERY_NEEDED(); Assert_NoQueryNeeded(); #else #define NSCAP_ASSERT_NO_QUERY_NEEDED(); #endif nsCOMPtr( const nsDontAddRef& aSmartPtr ) : NSCAP_CTOR_BASE(aSmartPtr.mRawPtr) { NSCAP_ASSERT_NO_QUERY_NEEDED(); } nsCOMPtr( const nsDontQueryInterface& aSmartPtr ) : NSCAP_CTOR_BASE(aSmartPtr.mRawPtr) { if ( mRawPtr ) NSCAP_ADDREF(mRawPtr); NSCAP_ASSERT_NO_QUERY_NEEDED(); } nsCOMPtr( const nsCOMPtr& aSmartPtr ) : NSCAP_CTOR_BASE(aSmartPtr.mRawPtr) { if ( mRawPtr ) NSCAP_ADDREF(mRawPtr); } nsCOMPtr( T* aRawPtr ) : NSCAP_CTOR_BASE(aRawPtr) { if ( mRawPtr ) NSCAP_ADDREF(mRawPtr); NSCAP_ASSERT_NO_QUERY_NEEDED(); } nsCOMPtr& operator=( T* rhs ) { assign_with_AddRef(rhs); NSCAP_ASSERT_NO_QUERY_NEEDED(); return *this; } nsCOMPtr& operator=( const nsQueryInterface& rhs ) { assign_with_QueryInterface(rhs.mRawPtr, nsCOMTypeInfo::GetIID(), rhs.mErrorPtr); return *this; } nsCOMPtr& operator=( const nsQueryReferent& rhs ) { assign_with_QueryReferent(rhs.mRawPtr, nsCOMTypeInfo::GetIID(), rhs.mErrorPtr); return *this; } nsCOMPtr& operator=( const nsDontAddRef& rhs ) { if ( mRawPtr ) NSCAP_RELEASE(mRawPtr); mRawPtr = rhs.mRawPtr; NSCAP_ASSERT_NO_QUERY_NEEDED(); return *this; } nsCOMPtr& operator=( const nsDontQueryInterface& rhs ) { assign_with_AddRef(rhs.mRawPtr); NSCAP_ASSERT_NO_QUERY_NEEDED(); return *this; } nsCOMPtr& operator=( const nsCOMPtr& rhs ) { assign_with_AddRef(rhs.mRawPtr); return *this; } nsDerivedSafe* get() const // returns a |nsDerivedSafe*| to deny clients the use of |AddRef| and |Release| { return NSCAP_REINTERPRET_CAST(nsDerivedSafe*, mRawPtr); } nsDerivedSafe* operator->() const // returns a |nsDerivedSafe*| to deny clients the use of |AddRef| and |Release| { NS_PRECONDITION(mRawPtr != 0, "You can't dereference a NULL nsCOMPtr with operator->()."); return get(); } nsDerivedSafe& operator*() const // returns a |nsDerivedSafe*| to deny clients the use of |AddRef| and |Release| { NS_PRECONDITION(mRawPtr != 0, "You can't dereference a NULL nsCOMPtr with operator*()."); return *get(); } operator nsDerivedSafe*() const { return get(); } #if 0 private: friend class nsGetterAddRefs; #endif T** StartAssignment() { #ifndef NSCAP_FEATURE_INLINE_STARTASSIGNMENT return NSCAP_REINTERPRET_CAST(T**, begin_assignment()); #else if ( mRawPtr ) NSCAP_RELEASE(mRawPtr); mRawPtr = 0; return NSCAP_REINTERPRET_CAST(T**, &mRawPtr); #endif } }; #ifdef NSCAP_FEATURE_DEBUG_PTR_TYPES template void nsCOMPtr::assign_with_AddRef( nsISupports* rawPtr ) { if ( rawPtr ) NSCAP_ADDREF(rawPtr); if ( mRawPtr ) NSCAP_RELEASE(mRawPtr); mRawPtr = NS_REINTERPRET_CAST(T*, rawPtr); } template void nsCOMPtr::assign_with_QueryInterface( nsISupports* rawPtr, const nsIID& iid, nsresult* result ) { nsresult status = NS_ERROR_NULL_POINTER; T* newPtr; if ( !rawPtr || !NS_SUCCEEDED( status = rawPtr->QueryInterface(iid, NSCAP_REINTERPRET_CAST(void**, &newPtr)) ) ) newPtr = 0; if ( mRawPtr ) NSCAP_RELEASE(mRawPtr); mRawPtr = newPtr; if ( result ) *result = status; } template void nsCOMPtr::assign_with_QueryReferent( nsIWeakReference* rawPtr, const nsIID& iid, nsresult* result ) { nsresult status = NS_ERROR_NULL_POINTER; T* newPtr; if ( !rawPtr || !NS_SUCCEEDED( status = rawPtr->QueryReferent(iid, NSCAP_REINTERPRET_CAST(void**, &newPtr)) ) ) newPtr = 0; if ( mRawPtr ) NSCAP_RELEASE(mRawPtr); mRawPtr = newPtr; if ( result ) *result = status; } template void** nsCOMPtr::begin_assignment() { if ( mRawPtr ) { NSCAP_RELEASE(mRawPtr); mRawPtr = 0; } return NSCAP_REINTERPRET_CAST(void**, &mRawPtr); } #endif template class nsGetterAddRefs /* ... This class is designed to be used for anonymous temporary objects in the argument list of calls that return COM interface pointers, e.g., nsCOMPtr fooP; ...->QueryInterface(iid, getter_AddRefs(fooP)) DO NOT USE THIS TYPE DIRECTLY IN YOUR CODE. Use |getter_AddRefs()| instead. When initialized with a |nsCOMPtr|, as in the example above, it returns a |void**| (or |T**| if needed) that the outer call (|QueryInterface| in this case) can fill in. This type should be a nested class inside |nsCOMPtr|. */ { public: explicit nsGetterAddRefs( nsCOMPtr& aSmartPtr ) : mTargetSmartPtr(aSmartPtr) { // nothing else to do } operator void**() { return NSCAP_REINTERPRET_CAST(void**, mTargetSmartPtr.StartAssignment()); } T*& operator*() { return *(mTargetSmartPtr.StartAssignment()); } operator T**() { return mTargetSmartPtr.StartAssignment(); } private: nsCOMPtr& mTargetSmartPtr; }; template inline nsGetterAddRefs getter_AddRefs( nsCOMPtr& aSmartPtr ) /* Used around a |nsCOMPtr| when ...makes the class |nsGetterAddRefs| invisible. */ { return nsGetterAddRefs(aSmartPtr); } class NSCAP_Zero; template inline NSCAP_BOOL operator==( const nsCOMPtr& lhs, const nsCOMPtr& rhs ) { return NSCAP_STATIC_CAST(const void*, lhs.get()) == NSCAP_STATIC_CAST(const void*, rhs.get()); } template inline NSCAP_BOOL operator==( const nsCOMPtr& lhs, const U* rhs ) { return NSCAP_STATIC_CAST(const void*, lhs.get()) == NSCAP_STATIC_CAST(const void*, rhs); } template inline NSCAP_BOOL operator==( const U* lhs, const nsCOMPtr& rhs ) { return NSCAP_STATIC_CAST(const void*, lhs) == NSCAP_STATIC_CAST(const void*, rhs.get()); } template inline NSCAP_BOOL operator==( const nsCOMPtr& lhs, NSCAP_Zero* rhs ) // specifically to allow |smartPtr == 0| { return NSCAP_STATIC_CAST(const void*, lhs.get()) == NSCAP_REINTERPRET_CAST(const void*, rhs); } template inline NSCAP_BOOL operator==( NSCAP_Zero* lhs, const nsCOMPtr& rhs ) // specifically to allow |0 == smartPtr| { return NSCAP_REINTERPRET_CAST(const void*, lhs) == NSCAP_STATIC_CAST(const void*, rhs.get()); } template inline NSCAP_BOOL operator!=( const nsCOMPtr& lhs, const nsCOMPtr& rhs ) { return NSCAP_STATIC_CAST(const void*, lhs.get()) != NSCAP_STATIC_CAST(const void*, rhs.get()); } template inline NSCAP_BOOL operator!=( const nsCOMPtr& lhs, const U* rhs ) { return NSCAP_STATIC_CAST(const void*, lhs.get()) != NSCAP_STATIC_CAST(const void*, rhs); } template inline NSCAP_BOOL operator!=( const U* lhs, const nsCOMPtr& rhs ) { return NSCAP_STATIC_CAST(const void*, lhs) != NSCAP_STATIC_CAST(const void*, rhs.get()); } template inline NSCAP_BOOL operator!=( const nsCOMPtr& lhs, NSCAP_Zero* rhs ) // specifically to allow |smartPtr != 0| { return NSCAP_STATIC_CAST(const void*, lhs.get()) != NSCAP_REINTERPRET_CAST(const void*, rhs); } template inline NSCAP_BOOL operator!=( NSCAP_Zero* lhs, const nsCOMPtr& rhs ) // specifically to allow |0 != smartPtr| { return NSCAP_REINTERPRET_CAST(const void*, lhs) != NSCAP_STATIC_CAST(const void*, rhs.get()); } inline NSCAP_BOOL SameCOMIdentity( nsISupports* lhs, nsISupports* rhs ) { return nsCOMPtr( do_QueryInterface(lhs) ) == nsCOMPtr( do_QueryInterface(rhs) ); } #if 0 // We don't really need this routine, and it confuses Solaris ... so out it goes template inline nsresult CallQueryInterface( nsISupports* aSource, nsCOMPtr* aDestination ) // a type-safe shortcut for calling the |QueryInterface()| member function { return CallQueryInterface(aSource, getter_AddRefs(*aDestination)); // this calls the _other_ |CallQueryInterface| } #endif #endif // !defined(nsCOMPtr_h___)