Re: [PATCH 1/2] Introduce string_appendf/string_vappendf (Re: [RFA 4/6] Simple cleanup removals in remote.c)

[Simon Marchi <simon.marchi@polymtl.ca>]

On 2017-10-18 23:12, Simon Marchi wrote:
> On 2017-10-18 23:11, Simon Marchi wrote:
>>> +
>>> +/* See documentation in common-utils.h.  */
>>> +
>>> +void
>>> +string_appendf (std::string &str, const char *fmt, ...)
>>> +{
>>> +  va_list vp;
>>> +  int grow_size;
>>> +
>>> +  va_start (vp, fmt);
>>> +  grow_size = vsnprintf (NULL, 0, fmt, vp);
>>> +  va_end (vp);
>>> +
>>> +  size_t curr_size = str.size ();
>>> +  str.resize (curr_size + grow_size);
>>> +
>>> +  /* C++11 and later guarantee std::string uses contiguous memory 
>>> and
>>> +     always includes the terminating '\0'.  */
>>> +  va_start (vp, fmt);
>>> +  vsprintf (&str[curr_size], fmt, vp);
>>> +  va_end (vp);
>>> +}
>>> +
>>> +
>>> +/* See documentation in common-utils.h.  */
>>> +
>>> +void
>>> +string_vappendf (std::string &str, const char *fmt, va_list args)
>>> +{
>>> +  va_list vp;
>>> +  int grow_size;
>>> +
>>> +  va_copy (vp, args);
>>> +  grow_size = vsnprintf (NULL, 0, fmt, vp);
>>> +  va_end (vp);
>>> +
>>> +  size_t curr_size = str.size ();
>>> +  str.resize (curr_size + grow_size);
>>> +
>>> +  /* C++11 and later guarantee std::string uses contiguous memory 
>>> and
>>> +     always includes the terminating '\0'.  */
>>> +  vsprintf (&str[curr_size], fmt, args);
>>> +}
>>> +
>> 
>> string_appendf can be implemented using string_vappendf, to reduce
>> duplication.  It would basically be like string_vappendf_wrapper is.
>> In the tests, we can probably just test string_appendf then.
>> 
>> Unless there's a good reason for them not sharing code?
> 
> Actually the same comment would apply to string_{v,}printf.
> 
> Simon

Hi Pedro,

I came across a case where string_appendf would be useful, so I was 
wondering if you intended to push this patch.  If you don't have the 
time, I would be happy to take care of it, just tell me if you agree 
with my comments and I'll make the changes & push.

Simon