nscomptr.h

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      operator nsDerivedSafe<nsISupports>*() const
          /*
            ...makes an |nsCOMPtr| act like its underlying raw pointer type (except against |AddRef()|, |Release()|,
              and |delete|) whenever it is used in a context where a raw pointer is expected.  It is this operator
              that makes an |nsCOMPtr| substitutable for a raw pointer.

            Prefer the implicit use of this operator to calling |get()|, except where necessary to resolve ambiguity.
          */
        {
          return get();
        }

      nsDerivedSafe<nsISupports>*
      operator->() const
        {
          NS_PRECONDITION(mRawPtr != 0, "You can't dereference a NULL nsCOMPtr with operator->().");
          return get();
        }

#ifdef CANT_RESOLVE_CPP_CONST_AMBIGUITY
  // broken version for IRIX

      nsCOMPtr<nsISupports>*
      get_address() const
          // This is not intended to be used by clients.  See |address_of|
          // below.
        {
          return NS_CONST_CAST(nsCOMPtr<nsISupports>*, this);
        }

#else // CANT_RESOLVE_CPP_CONST_AMBIGUITY

      nsCOMPtr<nsISupports>*
      get_address()
          // This is not intended to be used by clients.  See |address_of|
          // below.
        {
          return this;
        }

      const nsCOMPtr<nsISupports>*
      get_address() const
          // This is not intended to be used by clients.  See |address_of|
          // below.
        {
          return this;
        }

#endif // CANT_RESOLVE_CPP_CONST_AMBIGUITY

    public:

      nsDerivedSafe<nsISupports>&
      operator*() const
        {
          NS_PRECONDITION(mRawPtr != 0, "You can't dereference a NULL nsCOMPtr with operator*().");
          return *get();
        }

#if 0
    private:
      friend class nsGetterAddRefs<nsISupports>;
#endif

      nsISupports**
      StartAssignment()
        {
#ifndef NSCAP_FEATURE_INLINE_STARTASSIGNMENT
          return NS_REINTERPRET_CAST(nsISupports**, begin_assignment());
#else
          assign_assuming_AddRef(0);
          return NS_REINTERPRET_CAST(nsISupports**, &mRawPtr);
#endif
        }
  };

#ifdef NSCAP_FEATURE_DEBUG_PTR_TYPES
template <class T>
void
nsCOMPtr<T>::assign_with_AddRef( nsISupports* rawPtr )
  {
    if ( rawPtr )
      NSCAP_ADDREF(this, rawPtr);
    assign_assuming_AddRef(NS_REINTERPRET_CAST(T*, rawPtr));
  }

template <class T>
void
nsCOMPtr<T>::assign_from_helper( const nsCOMPtr_helper& helper, const nsIID& aIID )
  {
    T* newRawPtr;
    if ( NS_FAILED( helper(aIID, NS_REINTERPRET_CAST(void**, &newRawPtr)) ) )
      newRawPtr = 0;
    assign_assuming_AddRef(newRawPtr);
  }

template <class T>
void**
nsCOMPtr<T>::begin_assignment()
  {
    assign_assuming_AddRef(0);
    return NS_REINTERPRET_CAST(void**, &mRawPtr);
  }
#endif

#ifdef CANT_RESOLVE_CPP_CONST_AMBIGUITY

// This is the broken version for IRIX, which can't handle the version below.

template <class T>
inline
nsCOMPtr<T>*
address_of( const nsCOMPtr<T>& aPtr )
  {
    return aPtr.get_address();
  }

#else // CANT_RESOLVE_CPP_CONST_AMBIGUITY

template <class T>
inline
nsCOMPtr<T>*
address_of( nsCOMPtr<T>& aPtr )
  {
    return aPtr.get_address();
  }

template <class T>
inline
const nsCOMPtr<T>*
address_of( const nsCOMPtr<T>& aPtr )
  {
    return aPtr.get_address();
  }

#endif // CANT_RESOLVE_CPP_CONST_AMBIGUITY

template <class T>
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<IFoo> 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**|, a |T**|, or an |nsISupports**| as needed, that the outer call (|QueryInterface| in this
      case) can fill in.

      This type should be a nested class inside |nsCOMPtr<T>|.
    */
  {
    public:
      explicit
      nsGetterAddRefs( nsCOMPtr<T>& aSmartPtr )
          : mTargetSmartPtr(aSmartPtr)
        {
          // nothing else to do
        }

#if defined(NSCAP_FEATURE_TEST_DONTQUERY_CASES) || defined(NSCAP_LOG_EXTERNAL_ASSIGNMENT)
     ~nsGetterAddRefs()
        {
#ifdef NSCAP_LOG_EXTERNAL_ASSIGNMENT
          NSCAP_LOG_ASSIGNMENT(NS_REINTERPRET_CAST(void *, address_of(mTargetSmartPtr)), mTargetSmartPtr.get());
#endif

#ifdef NSCAP_FEATURE_TEST_DONTQUERY_CASES
          mTargetSmartPtr.Assert_NoQueryNeeded();
#endif
        }
#endif

      operator void**()
        {
          return NS_REINTERPRET_CAST(void**, mTargetSmartPtr.StartAssignment());
        }

      operator nsISupports**()
        {
          return NS_REINTERPRET_CAST(nsISupports**, mTargetSmartPtr.StartAssignment());
        }

      operator T**()
        {
          return mTargetSmartPtr.StartAssignment();
        }

      T*&
      operator*()
        {
          return *(mTargetSmartPtr.StartAssignment());
        }

    private:
      nsCOMPtr<T>& mTargetSmartPtr;
  };


NS_SPECIALIZE_TEMPLATE
class nsGetterAddRefs<nsISupports>
  {
    public:
      explicit
      nsGetterAddRefs( nsCOMPtr<nsISupports>& aSmartPtr )
          : mTargetSmartPtr(aSmartPtr)
        {
          // nothing else to do
        }

#ifdef NSCAP_LOG_EXTERNAL_ASSIGNMENT
     ~nsGetterAddRefs()
        {
          NSCAP_LOG_ASSIGNMENT(NS_REINTERPRET_CAST(void *, address_of(mTargetSmartPtr)), mTargetSmartPtr.get());
        }
#endif

      operator void**()
        {
          return NS_REINTERPRET_CAST(void**, mTargetSmartPtr.StartAssignment());
        }

      operator nsISupports**()
        {
          return mTargetSmartPtr.StartAssignment();
        }

      nsISupports*&
      operator*()
        {
          return *(mTargetSmartPtr.StartAssignment());
        }

    private:
      nsCOMPtr<nsISupports>& mTargetSmartPtr;
  };


template <class T>
inline
nsGetterAddRefs<T>
getter_AddRefs( nsCOMPtr<T>& aSmartPtr )
    /*
      Used around a |nsCOMPtr| when 
      ...makes the class |nsGetterAddRefs<T>| invisible.
    */
  {
    return nsGetterAddRefs<T>(aSmartPtr);
  }



  // Comparing two |nsCOMPtr|s

template <class T, class U>
inline
NSCAP_BOOL
operator==( const nsCOMPtr<T>& lhs, const nsCOMPtr<U>& rhs )
  {
    return NS_STATIC_CAST(const void*, lhs.get()) == NS_STATIC_CAST(const void*, rhs.get());
  }


template <class T, class U>
inline
NSCAP_BOOL
operator!=( const nsCOMPtr<T>& lhs, const nsCOMPtr<U>& rhs )
  {
    return NS_STATIC_CAST(const void*, lhs.get()) != NS_STATIC_CAST(const void*, rhs.get());
  }


  // Comparing an |nsCOMPtr| to a raw pointer

template <class T, class U>
inline
NSCAP_BOOL
operator==( const nsCOMPtr<T>& lhs, const U* rhs )
  {
    return NS_STATIC_CAST(const void*, lhs.get()) == NS_STATIC_CAST(const void*, rhs);
  }

template <class T, class U>
inline
NSCAP_BOOL
operator==( const U* lhs, const nsCOMPtr<T>& rhs )
  {
    return NS_STATIC_CAST(const void*, lhs) == NS_STATIC_CAST(const void*, rhs.get());
  }

template <class T, class U>
inline
NSCAP_BOOL
operator!=( const nsCOMPtr<T>& lhs, const U* rhs )
  {
    return NS_STATIC_CAST(const void*, lhs.get()) != NS_STATIC_CAST(const void*, rhs);
  }

template <class T, class U>
inline
NSCAP_BOOL
operator!=( const U* lhs, const nsCOMPtr<T>& rhs )
  {
    return NS_STATIC_CAST(const void*, lhs) != NS_STATIC_CAST(const void*, rhs.get());
  }

  // To avoid ambiguities caused by the presence of builtin |operator==|s
  // creating a situation where one of the |operator==| defined above
  // has a better conversion for one argument and the builtin has a
  // better conversion for the other argument, define additional
  // |operator==| without the |const| on the raw pointer.
  // See bug 65664 for details.

// This is defined by an autoconf test, but VC++ also has a bug that
// prevents us from using these.  (It also, fortunately, has the bug
// that we don't need them either.)
#ifdef _MSC_VER
#define NSCAP_DONT_PROVIDE_NONCONST_OPEQ
#endif

#ifndef NSCAP_DONT_PROVIDE_NONCONST_OPEQ
template <class T, class U>
inline
NSCAP_BOOL
operator==( const nsCOMPtr<T>& lhs, U* rhs )
  {
    return NS_STATIC_CAST(const void*, lhs.get()) == NS_STATIC_CAST(void*, rhs);
  }

template <class T, class U>
inline
NSCAP_BOOL
operator==( U* lhs, const nsCOMPtr<T>& rhs )
  {
    return NS_STATIC_CAST(void*, lhs) == NS_STATIC_CAST(const void*, rhs.get());
  }

template <class T, class U>
inline
NSCAP_BOOL
operator!=( const nsCOMPtr<T>& lhs, U* rhs )
  {
    return NS_STATIC_CAST(const void*, lhs.get()) != NS_STATIC_CAST(void*, rhs);
  }

template <class T, class U>
inline
NSCAP_BOOL
operator!=( U* lhs, const nsCOMPtr<T>& rhs )
  {
    return NS_STATIC_CAST(void*, lhs) != NS_STATIC_CAST(const void*, rhs.get());
  }
#endif



  // Comparing an |nsCOMPtr| to |0|

class NSCAP_Zero;

template <class T>
inline
NSCAP_BOOL
operator==( const nsCOMPtr<T>& lhs, NSCAP_Zero* rhs )
    // specifically to allow |smartPtr == 0|
  {
    return NS_STATIC_CAST(const void*, lhs.get()) == NS_REINTERPRET_CAST(const void*, rhs);
  }

template <class T>
inline
NSCAP_BOOL
operator==( NSCAP_Zero* lhs, const nsCOMPtr<T>& rhs )
    // specifically to allow |0 == smartPtr|
  {
    return NS_REINTERPRET_CAST(const void*, lhs) == NS_STATIC_CAST(const void*, rhs.get());
  }

template <class T>
inline
NSCAP_BOOL
operator!=( const nsCOMPtr<T>& lhs, NSCAP_Zero* rhs )
    // specifically to allow |smartPtr != 0|
  {
    return NS_STATIC_CAST(const void*, lhs.get()) != NS_REINTERPRET_CAST(const void*, rhs);
  }

template <class T>
inline
NSCAP_BOOL
operator!=( NSCAP_Zero* lhs, const nsCOMPtr<T>& rhs )
    // specifically to allow |0 != smartPtr|
  {
    return NS_REINTERPRET_CAST(const void*, lhs) != NS_STATIC_CAST(const void*, rhs.get());
  }


#ifdef HAVE_CPP_TROUBLE_COMPARING_TO_ZERO

  // We need to explicitly define comparison operators for `int'
  // because the compiler is lame.

template <class T>
inline
NSCAP_BOOL
operator==( const nsCOMPtr<T>& lhs, int rhs )
    // specifically to allow |smartPtr == 0|
  {
    return NS_STATIC_CAST(const void*, lhs.get()) == NS_REINTERPRET_CAST(const void*, rhs);
  }

template <class T>
inline
NSCAP_BOOL
operator==( int lhs, const nsCOMPtr<T>& rhs )
    // specifically to allow |0 == smartPtr|
  {
    return NS_REINTERPRET_CAST(const void*, lhs) == NS_STATIC_CAST(const void*, rhs.get());
  }

#endif // !defined(HAVE_CPP_TROUBLE_COMPARING_TO_ZERO)

  // Comparing any two [XP]COM objects for identity

inline
NSCAP_BOOL
SameCOMIdentity( nsISupports* lhs, nsISupports* rhs )
  {
    return nsCOMPtr<nsISupports>( do_QueryInterface(lhs) ) == nsCOMPtr<nsISupports>( do_QueryInterface(rhs) );
  }



template <class SourceType, class DestinationType>
inline
nsresult
CallQueryInterface( nsCOMPtr<SourceType>& aSourcePtr, DestinationType** aDestPtr )
  {
    return CallQueryInterface(aSourcePtr.get(), aDestPtr);
  }

#endif // !defined(nsCOMPtr_h___)