RFR(xs): 8224487: outputStream should not be copyable

[Kim Barrett]

> On May 21, 2019, at 2:28 PM, Thomas Stüfe <thomas.stuefe at gmail.com> wrote:
> 
> 
> 
> On Tue, May 21, 2019 at 8:23 PM Kim Barrett <kim.barrett at oracle.com> wrote:
> > On May 21, 2019, at 12:20 PM, Thomas Stüfe <thomas.stuefe at gmail.com> wrote:
> > src/hotspot/share/utilities/exceptions.hpp
> >  189   static void log_exception(Handle exception, stringStream tempst);
> > =>
> >  189   static void log_exception(Handle exception, const char* message);
> > 
> > Why not change the stringStream parameter to be passed by const-ref
> > rather than by value?  That would avoid changing all the callers.
> > 
> > 
> > Because handing the whole stream object down to log_exception was overkill anyway. All it wants is to print a text message, so I just give it that and live with a slightly larger patch diff. 
> > 
> > Also, I am not a big fan of references but that is just me. I usually prefer to see at the call site if I hand in value or reference without looking up the prototype.
> 
> [Oops, I missed the bug introduced into log_exception by webrev.00;  I
> was focused on the question of the parameter change.]
> 
> 
> Yes me too :( Shouldn't have renamed that thing in the first place. Thanks to jdk-submit tests I still got that.
>  
> I disagree, for a number of reasons, but mostly because passing by
> const-ref is completely normal for C++.  One doesn't need to look at
> the prototype to determine value vs const-ref passing, because from
> the caller's POV it doesn't matter.
> 
> 
> Okay, I see your point.
> 
> Are you still okay with this version? My original reasoning still holds - a const char* is sufficient at this place, log_exception does not need to take the whole stringStream.
>  

After thinking about it some more, yes, though not *precisely* for that reason.
Rather, it seems a bit odd that there should be any knowledge of stringStream
in this API.  So...

> delta: http://cr.openjdk.java.net/~stuefe/webrevs/8224487-make-streams-not-copyable/webrev_delta.01/webrev/
> full: http://cr.openjdk.java.net/~stuefe/webrevs/8224487-make-streams-not-copyable/webrev.01/webrev/
> 

Looks good.