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

[Wenchao Xia <xiawenc@linux.vnet.ibm.com>]

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