Re: [RFC 4/6] scripts/simpletrace-rust: Parse and check trace recode file

[Zhao Liu <zhao1.liu@intel.com>]

> > +fn read_trace_records(
> > +    events: &Vec<Event>,
> > +    fobj: &File,
> > +    analyzer: &mut Formatter,
> > +    read_header: bool,
> > +) -> Result<Vec<String>>
> > +{
> > +    /* backtrace::Backtrace needs this env variable. */
> > +    env::set_var("RUST_BACKTRACE", "1");
> > +    let bt = Backtrace::new();
> > +    let raw_frame = bt.frames().first().unwrap();
> > +    let frameinfo = raw_frame.symbols().first().unwrap();
> > +
> > +    let dropped_event = Event::build(
> > +        "Dropped_Event(uint64_t num_events_dropped)",
> > +        frameinfo.lineno().unwrap() + 1,
> > +        frameinfo.filename().unwrap().to_str().unwrap(),
> > +    )
> > +    .unwrap();
> 
> Is the backtrace necessary? This trick was used in Python where it's
> part of the standard library, but I don't think there is any need for
> Dropped_Event to refer to this line in the source code.
>
> Maybe Rust has a way to do this at compile-time or you can hardcode
> values instead.

Thanks your reminder, I'll think about the hardcode approach as the
easiest solution...removing the backtrace can help a lot here.

Regards,
Zhao