Re: Integrating QOM into QAPI

["Daniel P. Berrangé" <berrange@redhat.com>]

On Mon, Jan 27, 2020 at 08:05:36PM +0100, Christophe de Dinechin wrote:
> 
> 
> > On 26 Jan 2020, at 16:04, Peter Maydell <peter.maydell@linaro.org> wrote:
> > 
> > On Sun, 26 Jan 2020 at 08:10, Christophe de Dinechin
> > <dinechin@redhat.com> wrote:
> >> I’m still puzzled as to why anybody would switch to something like
> >> GObject when there is C++.
> > 
> > I'm fairly strongly against using C++.
> 
> Just to be clear, so am I ;-)
> 
> > C++'s language design
> > is an "everything including the kitchen sink, lots of "this
> > is here for back compat but it's a bear trap", lots of new
> > stuff arriving all the time.
> 
> Actually, the new stuff is not that bad, overall.
> 
> I do agree C++ is an overly complicated language, and that in
> practice, there is zero chance of qemu moving to it. But that does
> not invalidate my point that creating a class in C++ is easier
> than creating a class in any C-based macro-heavy reinvention
> of basic OO concepts.
> 
> (I write this after having read Paolo’s response, which points
> out IMO better reasons for GObject, which I will discuss there).
> 
> > It's just too big to keep in
> > your head all at once. C has its faults, absolutely, but at
> > least it tries to be a reasonably sized vaguely coherent
> > language.
> > 
> > You'd have more luck persuading me we should move to Rust:
> > at least then we'd get some clear benefits (no more buffer
> > overrun security bugs) for the upheaval :-)
> 
> This is largely a myth as soon as you need to do “your own stuff”.
> Example: CVE-2019-18960, https://seclists.org/oss-sec/2019/q4/141.

Calling it a "myth" from from that one data point is not really credible.

No language is perfect & such that it can eliminate all possible CVEs.
Rust *can*, however, eliminate a very large set of bugs which lead to 
memory corruption in unchecked languages like C/C++.  You'll still have
CVEs to deal with, but they'll be different classes of bugs, or rare
edge cases like the one you show above.

Regards,
Daniel
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