dir: move starts_with_dot(_dot)_slash to dir.h

Both submodule--helper.c and submodule-config.c have an implementation
of starts_with_dot_slash and starts_with_dot_dot_slash. The dir.h header
has starts_with_dot(_dot)_slash_native, which sets PATH_MATCH_NATIVE.

Move the helpers to dir.h as static inlines. I thought about renaming
them to postfix with _platform but that felt too long and ugly. On the
other hand it might be slightly confusing with _native.

This simplifies a submodule refactor which wants to use the helpers
earlier in the submodule--helper.c file.

Signed-off-by: Jacob Keller <jacob.keller@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/submodule--helper.c

@@ -438,18 +438,6 @@ cleanup:
 	return ret;
 }
 
-static int starts_with_dot_slash(const char *const path)
-{
-	return path_match_flags(path, PATH_MATCH_STARTS_WITH_DOT_SLASH |
-				PATH_MATCH_XPLATFORM);
-}
-
-static int starts_with_dot_dot_slash(const char *const path)
-{
-	return path_match_flags(path, PATH_MATCH_STARTS_WITH_DOT_DOT_SLASH |
-				PATH_MATCH_XPLATFORM);
-}
-
 struct init_cb {
 	const char *prefix;
 	const char *super_prefix;

dir.h

@@ -676,4 +676,27 @@ static inline int starts_with_dot_dot_slash_native(const char *const path)
 	return path_match_flags(path, what | PATH_MATCH_NATIVE);
 }
 
+/**
+ * starts_with_dot_slash: convenience wrapper for
+ * patch_match_flags() with PATH_MATCH_STARTS_WITH_DOT_SLASH and
+ * PATH_MATCH_XPLATFORM.
+ */
+static inline int starts_with_dot_slash(const char *const path)
+{
+	const enum path_match_flags what = PATH_MATCH_STARTS_WITH_DOT_SLASH;
+
+	return path_match_flags(path, what | PATH_MATCH_XPLATFORM);
+}
+
+/**
+ * starts_with_dot_dot_slash: convenience wrapper for
+ * patch_match_flags() with PATH_MATCH_STARTS_WITH_DOT_DOT_SLASH and
+ * PATH_MATCH_XPLATFORM.
+ */
+static inline int starts_with_dot_dot_slash(const char *const path)
+{
+	const enum path_match_flags what = PATH_MATCH_STARTS_WITH_DOT_DOT_SLASH;
+
+	return path_match_flags(path, what | PATH_MATCH_XPLATFORM);
+}
 #endif

submodule-config.c

@@ -235,18 +235,6 @@ in_component:
 	return 0;
 }
 
-static int starts_with_dot_slash(const char *const path)
-{
-	return path_match_flags(path, PATH_MATCH_STARTS_WITH_DOT_SLASH |
-				PATH_MATCH_XPLATFORM);
-}
-
-static int starts_with_dot_dot_slash(const char *const path)
-{
-	return path_match_flags(path, PATH_MATCH_STARTS_WITH_DOT_DOT_SLASH |
-				PATH_MATCH_XPLATFORM);
-}
-
 static int submodule_url_is_relative(const char *url)
 {
 	return starts_with_dot_slash(url) || starts_with_dot_dot_slash(url);