Re: [Qemu-devel] [PATCH 2/6] snapshot: add error set function

[Wenchao Xia]

于 2013-1-4 22:55, Stefan Hajnoczi 写道:
> On Mon, Dec 17, 2012 at 02:25:05PM +0800, Wenchao Xia wrote:
>
> This patch has nothing to do with snapshots, so "snapshot: add error set
> function" is not a useful commit message.  "error: add
> error_set_replace()" would be okay.  Please use git log <filename> on
> the file you are modifying to find good component names (e.g. "block:",
> "error:").
>
> > @@ -29,6 +29,9 @@ typedef struct Error Error;
> >    */
> >   void error_set(Error **err, ErrorClass err_class, const char *fmt, ...) 
> > GCC_FMT_ATTR(3, 4);
> >
> > +void error_set_replace(Error **err, ErrorClass err_class, const char *fmt, ...)
> > +GCC_FMT_ATTR(3, 4);
> > +
> >   /**
> >    * Set an indirect pointer to an error given a ErrorClass value and a
> >    * printf-style human message, followed by a strerror() string if
> > @@ -43,6 +46,12 @@ void error_set_errno(Error **err, int os_error, ErrorClass 
> > err_class, const char
> >       error_set(err, ERROR_CLASS_GENERIC_ERROR, fmt, ## __VA_ARGS__)
> >   #define error_setg_errno(err, os_error, fmt, ...) \
> >       error_set_errno(err, os_error, ERROR_CLASS_GENERIC_ERROR, fmt, ## 
> > __VA_ARGS__)
> > +#define error_setg_replace(err, fmt, ...) do {                     \
> > +    if (*err != NULL) { \
> > +        error_free(*err); \
> > +     } \
> > +    error_set(err, ERROR_CLASS_GENERIC_ERROR, fmt, ## __VA_ARGS__); \
> > +} while (/*CONSTCOND*/0)
>
> Why not use error_set_replace() to get rid of the error_free() check?
>
> Stefan

  It will be changed to error_set_check() which only set error when
*err is not set, to keep first error not over written.

--
Best Regards

Wenchao Xia