On Sun, Jun 03, 2018 at 11:56:37PM -0400, Jeff King wrote:
> So sometimes some_var needs to be freed and sometimes not (and every one
> of those uses is a potential leak, but it's OK because they're all
> program-lifetime globals anyway, and people don't _tend_ to set the same
> option over and over, leaking heap memory). And C being C, we can't
> convert a pointer-to-pointer-to-const into a pointer-to-pointer without
> an explicit cast.
>
> Doing it "right" in C would probably involve two variables:
>
> const char *some_var = "default";
> const char *some_var_storage = NULL;
>
> int git_config_string_smart(const char **ptr, char **storage,
> const char *var, const char *value)
> {
> ...
> free(*storage);
> *ptr = *storage = xstrdup(value);
> return 0;
> }
>
> #define GIT_CONFIG_STRING(name, var, value) \
> git_config_string_smart(&(name), &(name##_storage), var, value)
>
> Or something like that.
Oh, one other option I forgot to mention: we already have an "intern"
hashmap helper. So we could just replace the xstrdup() with strintern()
and magically the memory isn't "leaked".
I think this is a little bit of a hack, though. It catches my:
[core]
editor = foo
editor = foo
case, because we only ever make one copy of the string "foo". But if I
do:
[core]
editor = 1
editor = 2
...
then we get unique strings. And while they're not _technically_ leaked,
since the hashmap still knows about them, they might as well be. They're
still wasting space through the duration of the program run.
-Peff
