Re: [PATCHES] Text <-> C string

"Brendan Jurd" <direvus(at)gmail(dot)com> writes:
> As discussed on -hackers, I'm trying to get rid of some redundant code
> by creating a widely useful set of functions to convert between text
> and C string in the backend.

> The new extern functions, declared in include/utils/builtins.h and
> defined in backend/utils/adt/varlena.c, are:

> char * text_cstring(const text *t)
> char * text_cstring_limit(const text *t, int len)
> text * cstring_text(const char *s)
> text * cstring_text_limit(const char *s, int len)

I started to look at applying this patch and immediately decided that
I didn't like these names --- it's exceeding un-obvious which direction
of conversion any one of the functions performs. Seems like every time
you wanted to call one, you'd be going back to look at the source code
to remember which to use.

What do people think of text_to_cstring? Or should we go with
TextPGetCString for consistency with the Datum-whacking macros? (I seem
to recall having argued against the latter idea, but am reconsidering.)
Or something else?

BTW, I suspect that the _limit functions are mostly useless ---
a quick look through the patch did not suggest that any of the places
using them really needed a limit. The point of, for instance,
TZ_STRLEN_MAX is to be able to use fixed-size local buffers, and
if you're going to pay for a palloc anyway then you might as well
forget it. (There might be some value in a strlcpy equivalent that
copies from a text datum into a limited-size caller-supplied buffer,
but that's not what we've got here.)

regards, tom lane