Re: [PATCH v3 1/2] abspath: add a function to resolve paths with missing components

["brian m. carlson" <sandals@crustytoothpaste.net>]

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On 2020-11-28 at 10:08:09, René Scharfe wrote:
> Am 28.11.20 um 00:19 schrieb brian m. carlson:
> > We'd like to canonicalize paths such that we can preserve any number of
> > trailing components that may be missing.  Let's add a function to do
> > that, taking the number of components to canonicalize, and make
> > strbuf_realpath a wrapper around it that allows just one component.
> >
> > Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
> > ---
> >  abspath.c | 33 ++++++++++++++++++++++++++++++++-
> >  cache.h   |  2 ++
> >  2 files changed, 34 insertions(+), 1 deletion(-)
> >
> > diff --git a/abspath.c b/abspath.c
> > index 6f15a418bb..1d8f3d007c 100644
> > --- a/abspath.c
> > +++ b/abspath.c
> > @@ -20,6 +20,7 @@ static void strip_last_component(struct strbuf *path)
> >  	/* Find start of the last component */
> >  	while (offset < len && !is_dir_sep(path->buf[len - 1]))
> >  		len--;
> > +
> >  	/* Skip sequences of multiple path-separators */
> >  	while (offset < len && is_dir_sep(path->buf[len - 1]))
> >  		len--;
> 
> Stray change?

Ah, yes.  I pulled out the old code from v2, but left the whitespace.
Will fix.

> Nitpicking: Do we need both empty lines?

No, we don't.

> >  /*
> >   * Return the real path (i.e., absolute path, with symlinks resolved
> >   * and extra slashes removed) equivalent to the specified path.  (If
> > @@ -80,6 +97,16 @@ static void get_root_part(struct strbuf *resolved, struct strbuf *remaining)
> >   */
> >  char *strbuf_realpath(struct strbuf *resolved, const char *path,
> >  		      int die_on_error)
> > +{
> > +	return strbuf_realpath_missing(resolved, path, 1, die_on_error);
> > +}
> > +
> > +/*
> > + * Just like strbuf_realpath, but allows specifying how many missing components
> > + * are permitted.  -1 may be specified to allow an unlimited number.
> > + */
> > +char *strbuf_realpath_missing(struct strbuf *resolved, const char *path,
> > +			      int missing_components, int die_on_error)
> >  {
> >  	struct strbuf remaining = STRBUF_INIT;
> >  	struct strbuf next = STRBUF_INIT;
> > @@ -128,8 +155,12 @@ char *strbuf_realpath(struct strbuf *resolved, const char *path,
> >  		strbuf_addbuf(resolved, &next);
> >
> >  		if (lstat(resolved->buf, &st)) {
> > +			int trailing_components = count_dir_separators(remaining.buf) +
> > +						  (remaining.len != 0);
> 
> Hmm, so you actually want to count path components, not separators.
> Perhaps like this?
> 
> 	static size_t count_components(const char *p)
> 	{
> 		size_t n = 0;
> 		while (*p) {
> 			while (*p && !is_dir_sep(*p))
> 				p++;
> 			while (is_dir_sep(*p))
> 				p++;
> 			n++;
> 		}
> 		return n;
> 	}

Yeah, I think that's nicer, and simpler, too.  Will reroll with that
fix.
-- 
brian m. carlson (he/him or they/them)
Houston, Texas, US

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