Re: [PATCH] fts: reduce two or more trailing spaces to just one, usually

[Jim Meyering]

Eric Blake wrote:

> On 09/04/2012 04:57 AM, Eric Blake wrote:
>>> * lib/fts.c (fts_open): Upon initialization, if a name ends in two
>>> or more slashes, trim all but the final one.  But if a name consists
>>> solely of two or more slashes, reduce it to "//", not to "/".
>>
>> For two slashes, that is correct.  But trimming "///" to "//" is a
>> violation of POSIX and fails on cygwin; "///" must be the same as "/",
>> not "///".
>>
>>> +++ b/lib/fts.c
>>> @@ -487,6 +487,14 @@ fts_open (char * const *argv,
>>>          for (root = NULL, nitems = 0; *argv != NULL; ++argv, ++nitems) {
>>>                  /* *Do* allow zero-length file names. */
>>>                  size_t len = strlen(*argv);
>>> +
>>> +                /* If there are two or more trailing slashes, trim all but 
>>> one,
>>> +                   but don't change "//" to "/".  */
>>> +                char const *v = *argv;
>>> +                if (2 < len && v[len - 1] == '/')
>>> +                  while (2 < len && v[len - 2] == '/')
>>> +                    --len;
>
> I think that this would do the right thing, though (notice that it
> strips all but 1 slash for anything longer than "//" to begin with):
>
> +                char const *v = *argv;
> +                if (2 < len && v[len - 1] == '/')
> +                  while (1 < len && v[len - 1] == '/')
> +                    --len;

Actually, that's not correct, either.
You changed both '2's in the while condition, but that would have the
effect of stripping all trailing slashes, whereas as the comment says,
I want to leave one, in general:

    -                  while (2 < len && v[len - 2] == '/')
    +                  while (1 < len && v[len - 1] == '/')

So I think the revised commit I posted is correct.  It does this:

    -                  while (2 < len && v[len - 2] == '/')
    +                  while (1 < len && v[len - 2] == '/')