mirror of
https://github.com/mozilla/gecko-dev.git
synced 2024-11-01 22:55:23 +00:00
669 lines
19 KiB
C++
669 lines
19 KiB
C++
/* -*- 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
|
|
|
|
|
|
/*
|
|
TO DO...
|
|
|
|
+ make alternative function for |getter_AddRefs| (or something)
|
|
+ make constructor for |nsQueryInterface| explicit (suddenly construct/assign from raw pointer becomes illegal)
|
|
+ Improve internal documentation
|
|
+ mention *&
|
|
+ alternatives for comparison
|
|
+ do_QueryInterface
|
|
*/
|
|
|
|
|
|
|
|
/* USER MANUAL
|
|
|
|
See also:
|
|
<http://www.meer.net/ScottCollins/doc/nsCOMPtr.html>, or
|
|
<http://www.mozilla.org/projects/xpcom/nsCOMPtr.html>
|
|
|
|
What is |nsCOMPtr|?
|
|
|
|
|nsCOMPtr| is a `smart-pointer'. It is a template class that acts, syntactically,
|
|
just like an ordinary pointer in C or C++, i.e., you can apply |*| or |->| to it to
|
|
`get to' what it points at. |nsCOMPtr| is smart in that, unlike a raw COM
|
|
interface pointer, |nsCOMPtr| manages |AddRef|, |Release|, and |QueryInterface|
|
|
_for_ you.
|
|
|
|
For instance, here is a typical snippet of code (at its most compact) where you assign
|
|
a COM interface pointer into a member variable:
|
|
|
|
NS_IF_RELEASE(mFoop); // If I have one already, I must release it before over-writing it.
|
|
if ( mFooP = aPtr ) // Now it's safe to assign it in, and, if it's not NULL
|
|
mFooP->AddRef(); // I must |AddRef| it, since I'll be holding on to it.
|
|
|
|
If our member variable |mFooP| were a |nsCOMPtr|, however, the snippet above
|
|
would look like this:
|
|
|
|
mFoop = aPtr; // Note: automatically |Release|s the old and |AddRef|s the new
|
|
|
|
|nsCOMPtr| helps you write code that is leak-proof, exception safe, and significantly
|
|
less verbose than you would with raw COM interface pointers. With |nsCOMPtr|, you
|
|
may never have to call |AddRef|, |Release|, or |QueryInterface| by hand.
|
|
|
|
|
|
You still have to understand COM. You still have to know which functions return
|
|
interface pointers that have already been |AddRef|ed and which don't. You still
|
|
have to ensure your program logic doesn't produce circularly referencing garbage.
|
|
|nsCOMPtr| is not a panacea. It is, however, helpful, easy to use, well-tested,
|
|
and polite. It doesn't require that a function author cooperate with you, nor does
|
|
your use force others to use it.
|
|
|
|
|
|
Where should I use |nsCOMPtr|?
|
|
|
|
...
|
|
|
|
|
|
Where _shouldn't_ I use |nsCOMPtr|?
|
|
|
|
In public interfaces... [[others]]
|
|
|
|
|
|
How does a |nsCOMPtr| differ from a raw pointer?
|
|
|
|
A |nsCOMPtr| differs, syntactically, from a raw COM interface pointer in three
|
|
ways:
|
|
|
|
+ It's declared differently, e.g.,
|
|
|
|
// instead of saying // you say
|
|
IFoo* fooP; nsCOMPtr<IFoo> fooP;
|
|
|
|
|
|
+ You can't call |AddRef| or |Release| through it,
|
|
|
|
fooP->AddRef(); // OK fooP->AddRef(); // Error: no permission
|
|
fooP->Release(); // OK fooP->Release(); // Error: no permission
|
|
|
|
|
|
+ You can't just apply an |&| to it to pass it to the typical `getter' function
|
|
|
|
AcquireFoo(&fooP); AcquireFoo( getter_AddRefs(fooP) );
|
|
GetFoo(&fooP); GetFoo( getter_doesnt_AddRef(fooP) );
|
|
|
|
|
|
How do I use |nsCOMPtr|?
|
|
|
|
Typically, you can use a |nsCOMPtr| exactly as you would a standard COM
|
|
interface pointer:
|
|
|
|
IFoo* fooP; nsCOMPtr<IFoo> fooP;
|
|
// ... // ...
|
|
fooP->SomeFunction(x, y, z); fooP->SomeFunction(x, y, z);
|
|
AnotherFunction(fooP); AnotherFunction(fooP);
|
|
|
|
if ( fooP ) if ( fooP )
|
|
// ... // ...
|
|
|
|
if ( fooP == barP ) if ( fooP == barP )
|
|
// ... // ...
|
|
|
|
There are some differences, though. In particular, you can't call |AddRef| or |Release|
|
|
through a |nsCOMPtr| directly, nor would you need to. |AddRef| is called for you
|
|
whenever you assign a COM interface pointer _into_ a |nsCOMPtr|. |Release| is
|
|
called on the old value, and also when the |nsCOMPtr| goes out of scope. Trying
|
|
to call |AddRef| or |Release| yourself will generate a compile-time error.
|
|
|
|
fooP->AddRef(); // fooP->AddRef(); // ERROR: no permission
|
|
fooP->Release(); // fooP->Release(); // ERROR: no permission
|
|
|
|
The final difference is that a bare |nsCOMPtr| (or rather a pointer to it) can't
|
|
be supplied as an argument to a function that `fills in' a COM interface pointer.
|
|
Rather it must be wrapped with a utility call that says whether the function calls
|
|
|AddRef| before returning, e.g.,
|
|
|
|
...->QueryInterface(riid, &fooP) ...->QueryInterface(riid, getter_AddRefs(fooP))
|
|
|
|
LookupFoo(&fooP); LookupFoo( getter_doesnt_AddRef(fooP) );
|
|
|
|
Don't worry. It's a compile-time error if you forget to wrap it.
|
|
|
|
Compare the raw-pointer way...
|
|
|
|
IFoo* foo = 0;
|
|
nsresult status = CreateIFoo(&foo);
|
|
if ( NS_SUCCEEDED(status) )
|
|
{
|
|
IBar* bar = 0;
|
|
if ( NS_SUCCEEDED(status = foo->QueryInterface(riid, &bar)) )
|
|
{
|
|
IFooBar* foobar = 0;
|
|
if ( NS_SUCCEEDED(status = CreateIFooBar(foo, bar, &foobar)) )
|
|
{
|
|
foobar->DoTheReallyHardThing();
|
|
foobar->Release();
|
|
}
|
|
bar->Release();
|
|
}
|
|
foo->Release();
|
|
}
|
|
|
|
|
|
|
|
To the smart-pointer way...
|
|
|
|
nsCOMPtr<IFoo> fooP;
|
|
nsresult status = CreateIFoo( getter_AddRefs(fooP) );
|
|
if ( NS_SUCCEEDED(status) )
|
|
if ( nsCOMPtr<IBar> barP( fooP ) )
|
|
{
|
|
nsCOMPtr<IFooBar> fooBarP;
|
|
if ( NS_SUCCEEDED(status = CreateIFooBar(fooP, barP, getter_AddRefs(fooBarP))) )
|
|
fooBarP->DoTheReallyHardThing();
|
|
}
|
|
|
|
|
|
Is there an easy way to convert my current code?
|
|
|
|
...
|
|
|
|
|
|
What do I have to beware of?
|
|
|
|
VC++ < 6.0 _can't_ handle the following situation
|
|
|
|
class nsIFoo; // forward declare some class
|
|
// ...
|
|
nsCOMPtr<nsIFoo> bar; // ERROR: incomplete type nsIFoo, etc.
|
|
|
|
Instead, you must make sure that you actually defined the underlying interface class, e.g.,
|
|
|
|
#include "nsIFoo.h" // fully defines |class nsIFoo|
|
|
// ...
|
|
nsCOMPtr<nsIFoo> bar; // no problem
|
|
|
|
Why is this? It's because VC++ tries to instantiate every member of the template
|
|
as soon as it sees the template declarations. Bad compiler. No cookie!
|
|
[[Thanks to mjudge, waterson, and pinkerton on this one.]]
|
|
|
|
|
|
Why does |getter_AddRefs| have such a funny name? I.e., why doesn't it follow our
|
|
naming conventions?
|
|
|
|
|getter_AddRefs| and |getter_doesnt_AddRef| use underscores for the same
|
|
reason our special macros do, quoting from our coding conventions "...to make them
|
|
stick out like a sore thumb". Note also that since |AddRef| is one word,
|
|
|getter_AddRefs| and |getter_doesnt_AddRef| couldn't have the right spacing if only inter-
|
|
caps were used.
|
|
*/
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
/*
|
|
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.
|
|
|
|
Ideally, we would want declarations like these in a configuration file
|
|
that everybody would get. Deciding exactly how to do that should
|
|
be part of the process of moving from experimental to production.
|
|
|
|
Update: ramiro is working on getting these into the configuration system.
|
|
*/
|
|
|
|
#if defined(__GNUG__) && (__GNUC_MINOR__ <= 90) && !defined(SOLARIS)
|
|
#define NSCAP_NO_MEMBER_USING_DECLARATIONS
|
|
|
|
#if (defined(LINUX) || defined(__bsdi__)) && (__GNUC_MINOR__ <= 7)
|
|
#define NSCAP_NEED_UNUSED_VIRTUAL_IMPLEMENTATIONS
|
|
#endif
|
|
#endif
|
|
|
|
#if defined(SOLARIS) && !defined(__GNUG__)
|
|
#define NSCAP_NO_BOOL
|
|
#define NSCAP_NO_EXPLICIT
|
|
#define NSCAP_NO_NEW_CASTS
|
|
#define NSCAP_NO_MEMBER_USING_DECLARATIONS
|
|
#endif
|
|
|
|
#if defined(_MSC_VER) && (_MSC_VER<1100)
|
|
#define NSCAP_NO_EXPLICIT
|
|
#define NSCAP_NO_BOOL
|
|
#endif
|
|
|
|
#if defined(IRIX)
|
|
#define NSCAP_NO_MEMBER_USING_DECLARATIONS
|
|
#define NSCAP_NO_EXPLICIT
|
|
#define NSCAP_NO_NEW_CASTS
|
|
#define NSCAP_NO_BOOL
|
|
#endif
|
|
|
|
|
|
#ifdef NSCAP_NO_EXPLICIT
|
|
#define explicit
|
|
#endif
|
|
|
|
#ifndef NSCAP_NO_NEW_CASTS
|
|
#define NSCAP_REINTERPRET_CAST(T,x) reinterpret_cast<T>(x)
|
|
#else
|
|
#define NSCAP_REINTERPRET_CAST(T,x) ((T)(x))
|
|
#endif
|
|
|
|
#ifndef NSCAP_NO_BOOL
|
|
typedef bool NSCAP_BOOL;
|
|
#else
|
|
typedef PRBool NSCAP_BOOL;
|
|
#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 T>
|
|
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|.
|
|
|
|
See |nsCOMPtr::operator->|, |nsCOMPtr::operator*|, et al.
|
|
*/
|
|
{
|
|
private:
|
|
#ifndef NSCAP_NO_MEMBER_USING_DECLARATIONS
|
|
using T::AddRef;
|
|
using T::Release;
|
|
#else
|
|
nsrefcnt AddRef();
|
|
nsrefcnt Release();
|
|
#endif
|
|
|
|
void operator delete( void* ); // NOT TO BE IMPLEMENTED
|
|
// declaring |operator delete| private makes calling delete on an interface pointer a compile error
|
|
|
|
nsDerivedSafe& operator=( const nsDerivedSafe& ); // NOT TO BE IMPLEMENTED
|
|
// you may not call |operator=()| through a dereferenced |nsCOMPtr|, because you'd get the wrong one
|
|
};
|
|
|
|
#if defined(NSCAP_NO_MEMBER_USING_DECLARATIONS) && defined(NSCAP_NEED_UNUSED_VIRTUAL_IMPLEMENTATIONS)
|
|
template <class T>
|
|
nsrefcnt
|
|
nsDerivedSafe<T>::AddRef()
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
template <class T>
|
|
nsrefcnt
|
|
nsDerivedSafe<T>::Release()
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
#endif
|
|
|
|
|
|
|
|
|
|
template <class T>
|
|
struct nsDontQueryInterface
|
|
/*
|
|
...
|
|
*/
|
|
{
|
|
explicit
|
|
nsDontQueryInterface( T* aRawPtr )
|
|
: mRawPtr(aRawPtr)
|
|
{
|
|
// nothing else to do here
|
|
}
|
|
|
|
T* mRawPtr;
|
|
};
|
|
|
|
template <class T>
|
|
inline
|
|
nsDontQueryInterface<T>
|
|
dont_QueryInterface( T* aRawPtr )
|
|
{
|
|
return nsDontQueryInterface<T>(aRawPtr);
|
|
}
|
|
|
|
|
|
|
|
|
|
struct nsQueryInterface
|
|
{
|
|
// explicit
|
|
nsQueryInterface( nsISupports* aRawPtr, nsresult* error = 0 )
|
|
: mRawPtr(aRawPtr),
|
|
mErrorPtr(error)
|
|
{
|
|
// nothing else to do here
|
|
}
|
|
|
|
nsISupports* mRawPtr;
|
|
nsresult* mErrorPtr;
|
|
};
|
|
|
|
inline
|
|
nsQueryInterface
|
|
do_QueryInterface( nsISupports* aRawPtr, nsresult* error = 0 )
|
|
{
|
|
return nsQueryInterface(aRawPtr, error);
|
|
}
|
|
|
|
|
|
|
|
|
|
template <class T>
|
|
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.
|
|
|
|
See also |getter_AddRefs()| and |class nsGetterAddRefs|.
|
|
*/
|
|
{
|
|
explicit
|
|
nsDontAddRef( T* aRawPtr )
|
|
: mRawPtr(aRawPtr)
|
|
{
|
|
// nothing else to do here
|
|
}
|
|
|
|
T* mRawPtr;
|
|
};
|
|
|
|
template <class T>
|
|
inline
|
|
nsDontAddRef<T>
|
|
dont_AddRef( T* aRawPtr )
|
|
/*
|
|
...makes typing easier, because it deduces the template type, e.g.,
|
|
you write |dont_AddRef(fooP)| instead of |nsDontAddRef<IFoo>(fooP)|.
|
|
|
|
Like the class it is shorthand for, you would rarely use this directly,
|
|
but rather through |getter_AddRefs|.
|
|
*/
|
|
{
|
|
return nsDontAddRef<T>(aRawPtr);
|
|
}
|
|
|
|
|
|
|
|
class nsCOMPtr_base
|
|
{
|
|
public:
|
|
|
|
nsCOMPtr_base( nsISupports* rawPtr = 0 )
|
|
: mRawPtr(rawPtr)
|
|
{
|
|
// nothing else to do here
|
|
}
|
|
|
|
~nsCOMPtr_base()
|
|
{
|
|
if ( mRawPtr )
|
|
NSCAP_RELEASE(mRawPtr);
|
|
}
|
|
|
|
NS_EXPORT void assign_with_AddRef( nsISupports* );
|
|
NS_EXPORT void assign_with_QueryInterface( nsISupports*, const nsIID&, nsresult* );
|
|
NS_EXPORT void** begin_assignment();
|
|
|
|
protected:
|
|
nsISupports* mRawPtr;
|
|
};
|
|
|
|
|
|
|
|
|
|
template <class T>
|
|
class nsCOMPtr : private nsCOMPtr_base
|
|
/*
|
|
...
|
|
*/
|
|
{
|
|
public:
|
|
typedef T element_type;
|
|
|
|
nsCOMPtr()
|
|
// : nsCOMPtr_base(0)
|
|
{
|
|
// nothing else to do here
|
|
}
|
|
|
|
nsCOMPtr( const nsQueryInterface& aSmartPtr )
|
|
// : nsCOMPtr_base(0)
|
|
{
|
|
assign_with_QueryInterface(aSmartPtr.mRawPtr, T::IID(), aSmartPtr.mErrorPtr);
|
|
}
|
|
|
|
nsCOMPtr( const nsDontAddRef<T>& aSmartPtr )
|
|
: nsCOMPtr_base(aSmartPtr.mRawPtr)
|
|
{
|
|
// nothing else to do here
|
|
}
|
|
|
|
nsCOMPtr( const nsDontQueryInterface<T>& aSmartPtr )
|
|
: nsCOMPtr_base(aSmartPtr.mRawPtr)
|
|
{
|
|
if ( mRawPtr )
|
|
NSCAP_ADDREF(mRawPtr);
|
|
}
|
|
|
|
nsCOMPtr( const nsCOMPtr<T>& aSmartPtr )
|
|
: nsCOMPtr_base(aSmartPtr.mRawPtr)
|
|
{
|
|
if ( mRawPtr )
|
|
NSCAP_ADDREF(mRawPtr);
|
|
}
|
|
|
|
nsCOMPtr<T>&
|
|
operator=( const nsQueryInterface& rhs )
|
|
{
|
|
assign_with_QueryInterface(rhs.mRawPtr, T::IID(), rhs.mErrorPtr);
|
|
return *this;
|
|
}
|
|
|
|
nsCOMPtr<T>&
|
|
operator=( const nsDontAddRef<T>& rhs )
|
|
{
|
|
if ( mRawPtr )
|
|
NSCAP_RELEASE(mRawPtr);
|
|
mRawPtr = rhs.mRawPtr;
|
|
return *this;
|
|
}
|
|
|
|
nsCOMPtr<T>&
|
|
operator=( const nsDontQueryInterface<T>& rhs )
|
|
{
|
|
assign_with_AddRef(rhs.mRawPtr);
|
|
return *this;
|
|
}
|
|
|
|
nsCOMPtr<T>&
|
|
operator=( const nsCOMPtr& rhs )
|
|
{
|
|
assign_with_AddRef(rhs.mRawPtr);
|
|
return *this;
|
|
}
|
|
|
|
nsDerivedSafe<T>*
|
|
get() const
|
|
// returns a |nsDerivedSafe<T>*| to deny clients the use of |AddRef| and |Release|
|
|
{
|
|
return NSCAP_REINTERPRET_CAST(nsDerivedSafe<T>*, mRawPtr);
|
|
}
|
|
|
|
nsDerivedSafe<T>*
|
|
operator->() const
|
|
// returns a |nsDerivedSafe<T>*| 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<T>&
|
|
operator*() const
|
|
// returns a |nsDerivedSafe<T>*| 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<T>*() const
|
|
{
|
|
return get();
|
|
}
|
|
|
|
#if 0
|
|
private:
|
|
friend class nsGetterAddRefs<T>;
|
|
|
|
/*
|
|
In a perfect world, the following member function, |StartAssignment|, would be private.
|
|
It is and should be only accessed by the closely related class |nsGetterAddRefs<T>|.
|
|
|
|
Unfortunately, some compilers---most notably VC++5.0---fail to grok the
|
|
friend declaration above or in any alternate acceptable form. So, physically
|
|
it will be public (until our compilers get smarter); but it is not to be
|
|
considered part of the logical public interface.
|
|
*/
|
|
#endif
|
|
|
|
T**
|
|
StartAssignment()
|
|
{
|
|
return NSCAP_REINTERPRET_CAST(T**, begin_assignment());
|
|
}
|
|
};
|
|
|
|
|
|
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, nsGetterAddRefs<IFoo>(fooP))
|
|
...->QueryInterface(iid, getter_AddRefs(fooP))
|
|
|
|
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. When this temporary object goes out of scope, just after
|
|
the call returns, its destructor assigned the resulting interface pointer, i.e.,
|
|
|QueryInterface|s result, into the |nsCOMPtr| it was initialized with.
|
|
|
|
See also |nsGetterDoesntAddRef|.
|
|
*/
|
|
{
|
|
public:
|
|
explicit
|
|
nsGetterAddRefs( nsCOMPtr<T>& aSmartPtr )
|
|
: mTargetSmartPtr(aSmartPtr)
|
|
{
|
|
// nothing else to do
|
|
}
|
|
|
|
operator void**()
|
|
{
|
|
// NS_PRECONDITION(mTargetSmartPtr != 0, "getter_AddRefs into no destination");
|
|
return NSCAP_REINTERPRET_CAST(void**, mTargetSmartPtr.StartAssignment());
|
|
}
|
|
|
|
T*&
|
|
operator*()
|
|
{
|
|
// NS_PRECONDITION(mTargetSmartPtr != 0, "getter_AddRefs into no destination");
|
|
return *(mTargetSmartPtr.StartAssignment());
|
|
}
|
|
|
|
operator T**()
|
|
{
|
|
// NS_PRECONDITION(mTargetSmartPtr != 0, "getter_AddRefs into no destination");
|
|
return mTargetSmartPtr.StartAssignment();
|
|
}
|
|
|
|
private:
|
|
nsCOMPtr<T>& 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);
|
|
}
|
|
|
|
|
|
|
|
|
|
#endif // !defined(nsCOMPtr_h___)
|