path.c: refactor relative_path(), not only strip prefix

Original design of relative_path() is simple, just strip the prefix
(*base) from the absolute path (*abs).

In most cases, we need a real relative path, such as: ../foo,
../../bar.  That's why there is another reimplementation
(path_relative()) in quote.c.

Borrow some codes from path_relative() in quote.c to refactor
relative_path() in path.c, so that it could return real relative
path, and user can reuse this function without reimplementing
his/her own.  The function path_relative() in quote.c will be
substituted, and I would use the new relative_path() function when
implementing the interactive git-clean later.

Different results for relative_path() before and after this refactor:

    abs path  base path  relative (original)  relative (refactor)
    ========  =========  ===================  ===================
    /a/b      /a/b       .                    ./
    /a/b/     /a/b       .                    ./
    /a        /a/b/      /a                   ../
    /         /a/b/      /                    ../../
    /a/c      /a/b/      /a/c                 ../c
    /x/y      /a/b/      /x/y                 ../../x/y

    a/b/      a/b/       .                    ./
    a/b/      a/b        .                    ./
    a         a/b        a                    ../
    x/y       a/b/       x/y                  ../../x/y
    a/c       a/b        a/c                  ../c

    (empty)   (null)     (empty)              ./
    (empty)   (empty)    (empty)              ./
    (empty)   /a/b       (empty)              ./
    (null)    (null)     (null)               ./
    (null)    (empty)    (null)               ./
    (null)    /a/b       (segfault)           ./

You may notice that return value "." has been changed to "./".
It is because:

 * Function quote_path_relative() in quote.c will show the relative
   path as "./" if abs(in) and base(prefix) are the same.

 * Function relative_path() is called only once (in setup.c), and
   it will be OK for the return value as "./" instead of ".".

Signed-off-by: Jiang Xin <worldhello.net@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Jiang Xin
2013-06-25 23:53:43 +08:00
committed by Junio C Hamano
parent 203439b284
commit e02ca72f70
5 changed files with 111 additions and 51 deletions

View File

@ -117,14 +117,16 @@ int main(int argc, char **argv)
}
if (argc == 4 && !strcmp(argv[1], "relative_path")) {
struct strbuf sb = STRBUF_INIT;
const char *in, *prefix, *rel;
normalize_argv_string(&in, argv[2]);
normalize_argv_string(&prefix, argv[3]);
rel = relative_path(in, prefix);
rel = relative_path(in, prefix, &sb);
if (!rel)
puts("(null)");
else
puts(strlen(rel) > 0 ? rel : "(empty)");
strbuf_release(&sb);
return 0;
}