dir API: add a generalized path_match_flags() function

Add a path_match_flags() function and have the two sets of
starts_with_dot_{,dot_}slash() functions added in
63e95beb085 (submodule: port resolve_relative_url from shell to C,
2016-04-15) and a2b26ffb1a8 (fsck: convert gitmodules url to URL
passed to curl, 2020-04-18) be thin wrappers for it.

As the latter of those notes the fsck version was copied from the
initial builtin/submodule--helper.c version.

Since the code added in a2b26ffb1a8 was doing really doing the same as
win32_is_dir_sep() added in 1cadad6f658 (git clone <url>
C:\cygwin\home\USER\repo' is working (again), 2018-12-15) let's move
the latter to git-compat-util.h is a is_xplatform_dir_sep(). We can
then call either it or the platform-specific is_dir_sep() from this
new function.

Let's likewise change code in various other places that was hardcoding
checks for "'/' || '\\'" with the new is_xplatform_dir_sep(). As can
be seen in those callers some of them still concern themselves with
':' (Mac OS classic?), but let's leave the question of whether that
should be consolidated for some other time.

As we expect to make wider use of the "native" case in the future,
define and use two starts_with_dot_{,dot_}slash_native() convenience
wrappers. This makes the diff in builtin/submodule--helper.c much
smaller.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 6 insertions, 17 deletions

diff --git a/fsck.c b/fsck.c
index 3ec500d707..dd4822ba1b 100644
--- a/fsck.c
+++ b/fsck.c
@@ -975,27 +975,16 @@ done:
 	return ret;
 }
 
-/*
- * Like builtin/submodule--helper.c's starts_with_dot_slash, but without
- * relying on the platform-dependent is_dir_sep helper.
- *
- * This is for use in checking whether a submodule URL is interpreted as
- * relative to the current directory on any platform, since \ is a
- * directory separator on Windows but not on other platforms.
- */
-static int starts_with_dot_slash(const char *str)
+static int starts_with_dot_slash(const char *const path)
 {
-	return str[0] == '.' && (str[1] == '/' || str[1] == '\\');
+	return path_match_flags(path, PATH_MATCH_STARTS_WITH_DOT_SLASH |
+				PATH_MATCH_XPLATFORM);
 }
 
-/*
- * Like starts_with_dot_slash, this is a variant of submodule--helper's
- * helper of the same name with the twist that it accepts backslash as a
- * directory separator even on non-Windows platforms.
- */
-static int starts_with_dot_dot_slash(const char *str)
+static int starts_with_dot_dot_slash(const char *const path)
 {
-	return str[0] == '.' && starts_with_dot_slash(str + 1);
+	return path_match_flags(path, PATH_MATCH_STARTS_WITH_DOT_DOT_SLASH |
+				PATH_MATCH_XPLATFORM);
 }
 
 static int submodule_url_is_relative(const char *url)