system_path(): simplify using strip_path_suffix(), and add suffix "git"

At least for the author of this patch, the logic in system_path() was
too hard to understand.  Using the function strip_path_suffix() documents
the idea of the code better.

The real change is to add the suffix "git", so that a runtime prefix will
be computed correctly even when the executable was called in /git/ as is
the case in msysGit (Windows insists to search the current directory
before the PATH when looking for an executable).

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Acked-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/exec_cmd.c b/exec_cmd.c
index f234066defd637dc3c048ba3d9eb43f1ecbad446..217c12577f52b8ff9d535a086ec75d54107ee01c 100644 (file)
--- a/exec_cmd.c
+++ b/exec_cmd.c
@@ -23,35 +23,10 @@ const char *system_path(const char *path)
        assert(argv0_path);
        assert(is_absolute_path(argv0_path));
 
-       if (!prefix) {
-               const char *strip[] = {
-                       GIT_EXEC_PATH,
-                       BINDIR,
-                       0
-               };
-               const char **s;
-
-               for (s = strip; *s; s++) {
-                       const char *sargv = argv0_path + strlen(argv0_path);
-                       const char *ss = *s + strlen(*s);
-                       while (argv0_path < sargv && *s < ss
-                               && (*sargv == *ss ||
-                                   (is_dir_sep(*sargv) && is_dir_sep(*ss)))) {
-                               sargv--;
-                               ss--;
-                       }
-                       if (*s == ss) {
-                               struct strbuf d = STRBUF_INIT;
-                               /* We also skip the trailing directory separator. */
-                               assert(sargv - argv0_path - 1 >= 0);
-                               strbuf_add(&d, argv0_path, sargv - argv0_path - 1);
-                               prefix = strbuf_detach(&d, NULL);
-                               break;
-                       }
-               }
-       }
-
-       if (!prefix) {
+       if (!prefix &&
+           !(prefix = strip_path_suffix(argv0_path, GIT_EXEC_PATH)) &&
+           !(prefix = strip_path_suffix(argv0_path, BINDIR)) &&
+           !(prefix = strip_path_suffix(argv0_path, "git"))) {
                prefix = PREFIX;
                fprintf(stderr, "RUNTIME_PREFIX requested, "
                                "but prefix computation failed.  "