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

[Simon Marchi]

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