Re: new module: relpath

[Eric Blake]

On 06/18/2012 09:30 AM, Eli Zaretskii wrote:

>> At least to experiment on the concept, and on a suggestion from
>> Eric Blake weeks ago, I stole bits of the coreutils, and made them
>> a gnulib module.
> 
> Perhaps the comments below, mainly related to portability to
> MS-Windows (but not only that) will be helpful, even though a lot has
> been said already.

Yes, porting to mingw would be helpful.

> 
>> +  while (*path1 && *path2)
>> +    {
>> +      if (*path1 != *path2)
> 
> This comparison should be case-insensitive for MS-Windows.

Shouldn't normalization already guarantee canonical case, so that by the
time we get here, case-sensitive comparison is correct?

> 
>> +  /* Skip over extraneous '/'.  */
>> +  if (*relto_suffix == '/')
>> +    relto_suffix++;
>> +  if (*fname_suffix == '/')
>> +    fname_suffix++;
> 
> Why do you skip only over a single slash?  Can't there be an
> arbitrarily long sequence of redundant slashes?

After canonicalization, there can be at most one location where you will
ever have consecutive '/', and that is in path names that start with //.

> 
>> +/* Return FROM represented as relative to the dir of TARGET.
>> +   The result is malloced.  */
> 
> This commentary doesn't say that the result can be NULL.

nor that NULL is _expected_ when two names have no relative relationship
(as is the case between /foo and //bar on systems where // is special,
or between a:/file and c:/file on windows).

> 
>> +
>> +char *
>> +convert_abs_rel (const char *from, const char *target)
>> +{
>> +  char *realtarget = canonicalize_filename_mode (target, CAN_MISSING);
>> +  char *realfrom = canonicalize_filename_mode (from, CAN_MISSING);
> 
> AFAICT, canonicalize_filename_mode can return NULL, but the rest of
> the code doesn't cope with that.

No, canonicalize_filename_mode is GPL because it calls xalloc() and dies
rather than return NULL.

-- 
Eric Blake   address@hidden    +1-919-301-3266
Libvirt virtualization library http://libvirt.org

signature.asc
Description: OpenPGP digital signature