Re: [Quantlib-dev] Dangerous constructor in Handle class

[Luigi B. <lui...@gm...>]

On Tue, 2011-07-19 at 18:03 -0400, Irakli Machabeli wrote:
> What is the purpose of this constructor for the handle class?
> 
> template <class T>
> inline Handle<T>::Handle(T* p,bool registerAsObserver)
> : link_(new Link(boost::shared_ptr<T>(p),registerAsObserver)) {}

I guess it's just a shortcut to avoid declaring the boost shared pointer
explicitly.  It's not much more dangerous than the shared_ptr
constructor (you can have the same problem) but I agree that at least it
should be documented.  I wouldn't remove it, because we're keeping
backward compatibility with previous releases; but we can mark it as
deprecated.

Luigi



> 
> If you create handle to something that you plan to delete later   or
> even worse to something that is on the stack (like I did by accident)
> implicit boost pointer  passed to Link will try to delete object that is not 
> supposed to be deleted.
> In my case luckily CRT caught invalid heap address.
> 
> Anyway, I commented out this constructor and both Quantlib and test suite 
> compile and run. The only place this constructor is used us in
> fdmbatesop.cpp (under experimental\finitedifference) and existing code can 
> be easily replaced with the following
>    FdmBatesOp::FdmBatesOp(
>                     const boost::shared_ptr<FdmMesher>& mesher,
>                     const boost::shared_ptr<BatesProcess>& batesProcess,
>                     const FdmBoundaryConditionSet& bcSet,
>                     const Size integroIntegrationOrder,
>                     const boost::shared_ptr<FdmQuantoHelper>& quantoHelper)
>     : lambda_(batesProcess->lambda()),
>       delta_ (batesProcess->delta()),
>       nu_    (batesProcess->nu()),
>       m_(std::exp(nu_+0.5*delta_*delta_)-1.0),
>       gaussHermiteIntegration_(integroIntegrationOrder),
>       mesher_(mesher),
>       bcSet_(bcSet),
>       hestonOp_(new FdmHestonOp(mesher,
>            boost::shared_ptr<HestonProcess>(new HestonProcess(
>                batesProcess->riskFreeRate(),
>                Handle<YieldTermStructure>(
>                     boost::shared_ptr<ZeroSpreadedTermStructure>(
>                    new ZeroSpreadedTermStructure(
>                            batesProcess->dividendYield(),
>                            Handle<Quote>(boost::shared_ptr<Quote>(new 
> SimpleQuote(lambda_*m_))),
>                            Continuous, NoFrequency,
>                            batesProcess->dividendYield()->dayCounter()))),
>                batesProcess->s0(),    batesProcess->v0(),
>                batesProcess->kappa(), batesProcess->theta(),
>                batesProcess->sigma(), batesProcess->rho())),
>            quantoHelper)) {
>     }
> 
> I just wrapped new in couple places inside a shared pointers
> 
> 
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