[rfc][icedtea-web] C++ unit-tests for memory leak w/ simple leak-detecting operator-new, along with fix

[Pavel Tisnovsky]

----- Adam Domurad <adomurad at redhat.com> wrote:
> On 12/20/2012 10:13 AM, Pavel Tisnovsky wrote:
> > Hi Adam,
> >
> > this patch looks very good in overall, but I'm not sure (=I'm dumb today) why can't you
> > simply use ::new and ::delete operators to override them in following place:
> >
> > +void* operator new(size_t size) throw (std::bad_alloc) {
> > +    if (!__allocations) {
> > +        // This uses placement-new, which calls the constructor on a specific memory location
> > +        // This is needed because we cannot call 'new' in this context, nor can we rely on static-initialization
> > +        // for the set to occur before any call to 'new'!
> > +        void* memory = malloc(sizeof(AllocationSet));
> > +        __allocations = new (memory) AllocationSet();
> > +    }
> > +
> > +    void* mem = malloc(size);
> > +    if (mem == 0) {
> > +        throw std::bad_alloc(); // ANSI/ISO compliant behavior
> > +    }
> > +    __allocations->insert(mem);
> > +    return mem;
> > +
> >
> > Cheers,
> > Pavel
> 
> As we discussed, this would be recursive.
> 
> http://stackoverflow.com/questions/4134195/how-do-i-call-the-original-operator-new-if-i-have-overloaded-it 
> 
> indicates that the only approach is to recreate operator-new using malloc.
> 
> Thanks, will push as is (as we also discussed off-list),
> -Adam

Yes, please do.

Thank you very much,
Pavel

> 
> >
> > ----- Adam Domurad <adomurad at redhat.com> wrote:
> >> The unit test infrastructure + tests:
> >> 2012-12-XX  Adam Domurad  <adomurad at redhat.com>
> >>
> >>       * tests/cpp-unit-tests/browser_mock.cc
> >>       (mock_retainobject): New, mocks behaviour of NPAPI retainobject
> >>       (mock_releaseobject): New, mocks behaviour of NPAPI releaseobject
> >>       * tests/cpp-unit-tests/main.cc: Add warning of memory leak based on
> >>       operator-new.
> >>       * tests/cpp-unit-tests/IcedTeaScriptablePluginObjectTest.cc: New, tests
> >>       for memory leak in (IcedTeaScriptableJavaObject::deAllocate) and
> >>       (IcedTeaScriptableJavaPackageObject::deAllocate)
> >>       * tests/cpp-unit-tests/checked_allocations.h: Defines set that does not
> >>       use operator-new, to prevent recursion in overloaded operator-new
> >>       * tests/cpp-unit-tests/checked_allocations.cc: Operator new overload
> >>       that has allocation-set for querying live allocations.
> >>
> >> The fix:
> >> 2012-12-XX  Adam Domurad  <adomurad at redhat.com>
> >>
> >>       * plugin/icedteanp/IcedTeaScriptablePluginObject.cc
> >>       (IcedTeaScriptableJavaObject::deAllocate): Fix memory leak
> >>       (IcedTeaScriptableJavaPackageObject::deAllocate): Fix memory leak
>