qemu-devel
[Top][All Lists]
Advanced

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Qemu-devel] [PATCH 03/14] qerror: drop qerror_abort()


From: Luiz Capitulino
Subject: Re: [Qemu-devel] [PATCH 03/14] qerror: drop qerror_abort()
Date: Thu, 26 Jul 2012 12:02:41 -0300

On Thu, 26 Jul 2012 14:33:23 +0200
Markus Armbruster <address@hidden> wrote:

> Luiz Capitulino <address@hidden> writes:
> 
> > Previously, developers had to create error dicts manually and also enter
> > the matching desc table entry. Thus, qerro_abort() was added to help
> 
> s/qerro_/qerror_/
> 
> > catching bad error dicts.
> >
> > Today, all that stuff is generated automatically which makes the chance
> > of a bad generated dict quite low.
> 
> The generator can only generate well-formed dicts, right?

I didn't say that. I said the chances of generating a bad dict is low,
specially in production.

> 
> > Also, qerror_abort() would... _abort_ on a bad error dict!
> 
> In my opinion, it's perfectly fine to abort on a programming error.

In this case it's quite easy to recover, so why should we abort?

> 
> > This commit maintains the same verification logic on the error object
> > but drops the abort() in favor of reporting UndefinedError for bad dicts
> > (and also print a debug message to stderr).
> 
> I certainly won't object to your elaborate handling, but me, I'd simply
> replace qerror_abort() by straight abort() and be done with it *shrug*

Well, honestly speaking, I did this while I was re-reading that code and
I ended up dropping it down this series (remember this is an RFC) :)

But I think I'll add it back for v1.

> 
> > Signed-off-by: Luiz Capitulino <address@hidden>
> > ---
> >  qerror.c | 83 
> > +++++++++++++++++++++++++++++++++++-----------------------------
> >  1 file changed, 46 insertions(+), 37 deletions(-)
> >
> > diff --git a/qerror.c b/qerror.c
> > index d428b52..74b3659 100644
> > --- a/qerror.c
> > +++ b/qerror.c
> > @@ -38,55 +38,50 @@ static QError *qerror_new(void)
> >      return qerr;
> >  }
> >  
> > -static void GCC_FMT_ATTR(2, 3) qerror_abort(const QError *qerr,
> > -                                            const char *fmt, ...)
> > -{
> > -    va_list ap;
> > -
> > -    fprintf(stderr, "qerror: bad call in function '%s':\n", qerr->func);
> > -    fprintf(stderr, "qerror: -> ");
> > -
> > -    va_start(ap, fmt);
> > -    vfprintf(stderr, fmt, ap);
> > -    va_end(ap);
> > -
> > -    fprintf(stderr, "\nqerror: call at %s:%d\n", qerr->file, qerr->linenr);
> > -    abort();
> > -}
> > -
> > -static void GCC_FMT_ATTR(2, 0) qerror_set_data(QError *qerr,
> > -                                               const char *fmt, va_list 
> > *va)
> > +static QDict *error_object_from_fmt(const char *fmt, va_list *va)
> >  {
> >      QObject *obj;
> > +    QDict *ret;
> >  
> >      obj = qobject_from_jsonv(fmt, va);
> >      if (!obj) {
> > -        qerror_abort(qerr, "invalid format '%s'", fmt);
> > +        fprintf(stderr, "invalid json in error dict '%s'\n", fmt);
> > +        return NULL;
> >      }
> >      if (qobject_type(obj) != QTYPE_QDICT) {
> > -        qerror_abort(qerr, "error format is not a QDict '%s'", fmt);
> > +        fprintf(stderr, "error is not a dict '%s'\n", fmt);
> > +        goto out_free;
> >      }
> >  
> > -    qerr->error = qobject_to_qdict(obj);
> > -
> > -    obj = qdict_get(qerr->error, "class");
> > +    ret = qobject_to_qdict(obj);
> > +    obj = qdict_get(ret, "class");
> >      if (!obj) {
> > -        qerror_abort(qerr, "missing 'class' key in '%s'", fmt);
> > +        fprintf(stderr, "missing 'class' key in '%s'\n", fmt);
> > +        goto out_free;
> >      }
> >      if (qobject_type(obj) != QTYPE_QSTRING) {
> > -        qerror_abort(qerr, "'class' key value should be a QString");
> > +        fprintf(stderr, "'class' key value should be a string in '%s'\n", 
> > fmt);
> > +        goto out_free;
> >      }
> > -    
> > -    obj = qdict_get(qerr->error, "data");
> > +
> > +    obj = qdict_get(ret, "data");
> >      if (!obj) {
> > -        qerror_abort(qerr, "missing 'data' key in '%s'", fmt);
> > +        fprintf(stderr, "missing 'data' key in '%s'\n", fmt);
> > +        goto out_free;
> >      }
> >      if (qobject_type(obj) != QTYPE_QDICT) {
> > -        qerror_abort(qerr, "'data' key value should be a QDICT");
> > +        fprintf(stderr, "'data' key value should be a dict in '%s'\n", 
> > fmt);
> > +        goto out_free;
> >      }
> > +
> > +    return ret;
> > +
> > +out_free:
> > +    qobject_decref(obj);
> > +    return NULL;
> >  }
> >  
> > -static void qerror_set_desc(QError *qerr, const char *fmt)
> > +static const QErrorStringTable *error_get_desc(const char *fmt)
> >  {
> >      int i;
> >  
> > @@ -94,12 +89,17 @@ static void qerror_set_desc(QError *qerr, const char 
> > *fmt)
> >  
> >      for (i = 0; qerror_table[i].error_fmt; i++) {
> >          if (strcmp(qerror_table[i].error_fmt, fmt) == 0) {
> > -            qerr->entry = &qerror_table[i];
> > -            return;
> > +            return &qerror_table[i];
> >          }
> >      }
> >  
> > -    qerror_abort(qerr, "error format '%s' not found", fmt);
> > +    fprintf(stderr, "error format '%s' not found\n", fmt);
> > +    return NULL;
> > +}
> > +
> > +static QDict *build_error_no_arg(const char *fmt)
> > +{
> > +    return qobject_to_qdict(qobject_from_jsonv(fmt, NULL));
> >  }
> >  
> >  /**
> > @@ -127,13 +127,22 @@ static QError *qerror_from_info(const char *file, int 
> > linenr, const char *func,
> >      qerr->file = file;
> >      qerr->func = func;
> >  
> > -    if (!fmt) {
> > -        qerror_abort(qerr, "QDict not specified");
> > +    qerr->error = error_object_from_fmt(fmt, va);
> > +    if (!qerr->error) {
> > +        goto bad_err;
> > +    }
> > +
> > +    qerr->entry = error_get_desc(fmt);
> > +    if (!qerr->entry) {
> > +        QDECREF(qerr->error);
> > +        goto bad_err;
> >      }
> >  
> > -    qerror_set_data(qerr, fmt, va);
> > -    qerror_set_desc(qerr, fmt);
> > +    return qerr;
> >  
> > +bad_err:
> > +    qerr->error = build_error_no_arg(QERR_UNDEFINED_ERROR);
> 
> Nit: defeats gcc's format checking.  This shouldn't:
> 
>        qerr->error = 
> qobject_to_qdict(qobject_from_json(QERR_UNDEFINED_ERROR));
> 
> > +    qerr->entry = error_get_desc(QERR_UNDEFINED_ERROR);
> >      return qerr;
> >  }
> 




reply via email to

[Prev in Thread] Current Thread [Next in Thread]