cache.h: complete set of git_path_submodule helpers

The git_path function has "git_pathdup" and
"strbuf_git_path" variants, but git_submodule_path only
comes in the dangerous, static-buffer variant. That makes
refactoring callers to use the safer functions hard (since
they don't exist).

Since we're already using a strbuf behind the scenes, it's
easy to expose all three of these interfaces with thin
wrappers.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

cache.h

@@ -724,10 +724,15 @@ extern char *mksnpath(char *buf, size_t n, const char *fmt, ...)
 	__attribute__((format (printf, 3, 4)));
 extern void strbuf_git_path(struct strbuf *sb, const char *fmt, ...)
 	__attribute__((format (printf, 2, 3)));
+extern void strbuf_git_path_submodule(struct strbuf *sb, const char *path,
+				      const char *fmt, ...)
+	__attribute__((format (printf, 3, 4)));
 extern char *git_pathdup(const char *fmt, ...)
 	__attribute__((format (printf, 1, 2)));
 extern char *mkpathdup(const char *fmt, ...)
 	__attribute__((format (printf, 1, 2)));
+extern char *git_pathdup_submodule(const char *path, const char *fmt, ...)
+	__attribute__((format (printf, 2, 3)));
 
 extern void report_linked_checkout_garbage(void);
 

path.c

@@ -224,11 +224,10 @@ const char *mkpath(const char *fmt, ...)
 	return cleanup_path(pathname->buf);
 }
 
-const char *git_path_submodule(const char *path, const char *fmt, ...)
+static void do_submodule_path(struct strbuf *buf, const char *path,
+			      const char *fmt, va_list args)
 {
-	struct strbuf *buf = get_pathname();
 	const char *git_dir;
-	va_list args;
 
 	strbuf_addstr(buf, path);
 	if (buf->len && buf->buf[buf->len - 1] != '/')
@@ -242,13 +241,39 @@ const char *git_path_submodule(const char *path, const char *fmt, ...)
 	}
 	strbuf_addch(buf, '/');
 
-	va_start(args, fmt);
 	strbuf_vaddf(buf, fmt, args);
-	va_end(args);
 	strbuf_cleanup_path(buf);
+}
+
+const char *git_path_submodule(const char *path, const char *fmt, ...)
+{
+	va_list args;
+	struct strbuf *buf = get_pathname();
+	va_start(args, fmt);
+	do_submodule_path(buf, path, fmt, args);
+	va_end(args);
 	return buf->buf;
 }
 
+char *git_pathdup_submodule(const char *path, const char *fmt, ...)
+{
+	va_list args;
+	struct strbuf buf = STRBUF_INIT;
+	va_start(args, fmt);
+	do_submodule_path(&buf, path, fmt, args);
+	va_end(args);
+	return strbuf_detach(&buf, NULL);
+}
+
+void strbuf_git_path_submodule(struct strbuf *buf, const char *path,
+			       const char *fmt, ...)
+{
+	va_list args;
+	va_start(args, fmt);
+	do_submodule_path(buf, path, fmt, args);
+	va_end(args);
+}
+
 int validate_headref(const char *path)
 {
 	struct stat st;