Sorry, in my last mail I have errors in examples about using the
TidyPointer. The deallocator function given as template parameter, not
as constructor parameters:
TidyPointer<A,freeA> a(newA());
and NOT :
TidyPointer<A> a(newA(),freeA);
On 11/11/2010 12:38 PM, Tsantilas Christos wrote:
On 11/11/2010 03:11 AM, Amos Jeffries wrote:
On Wed, 10 Nov 2010 17:05:16 +0200, Tsantilas Christos
* Introduce the TidyPointer class similar to std::auto_ptr, which
implements a pointer that deletes the object it points to when the
pointer's owner or context is gone. It is designed to avoid memory
leaks in the presence of exceptions and processing short cuts.
So whats different about this new pointer type that the existing
std:auto_ptr, RefCount::Pointer and CbcPointer are all insufficient?
The TidyPointer is completely different than RefCount and CbcPointers.
It is similar to the std::auto_ptr but allow developer to define the
deallocator method for the object it points to.
Also does not implement the "=" operator and prevents developers from
using the copy constructor.
It can be usefull when you have code as the following:
-----------------------
A *a= newA();
if (!a)
return NULL;
B *b=newB();
if (!b) {
freeA(a);
return NULL;
}
C *c=newC();
if (!c) {
freeA(a);
freeB(b);
return NULL;
}
If(problem){
freeA(a);
freeB(b);
freeC(c);
return NULL;
}
return C;
Using TidyPointer the above can be written as:
TidyPointer<A> a(newA(),freeA);
if (!a)
return NULL;
TidyPointer<B> b(newB(),freeB);
if (!b)
return NULL;
TidyPointer<C> c(newC(), freeC);
if (!c)
return NULL;
if (problem)
return NULL;
return C.release();
Can help you to avoid memory leeks when you have the following case:
A *a= newA();
DoSomeWorkWhichMayThrow(a);
freeA(a);
In the above case if the DoSomeWorkWhichMayThrow() throws the a object
will never be released.
The above can be written:
TidyPointer<A> a(newA(),freeA);
DoSomeWorkWhichMayThrow(a.get());
From what I've heard of the SSL problems they are all cause by it not
using RefCount on the contexts themselves.
Maybe RefCount is usefull for the SSL_CTX objects. But I do not think it
is required.
In most cases using the openSSL library you have code like the following:
a=NewA();
b=newB(a);
if (!b) {
freeA(a);
}
else {
//Just forget the a
}
I these cases the TidyPointer is very useful.
Regards,
Christos
