[WIP RFC PATCH 3/7] clone: extract function from copy_or_link_directory

["Ævar Arnfjörð Bjarmason" <avarab@gmail.com>]

From: Matheus Tavares <matheus.bernardino@usp.br>

Extract dir creation code snippet from copy_or_link_directory to its own
function named mkdir_if_missing. This change will help removing
copy_or_link_directory's explicit recursion, which will be done in a
following patch. Also makes code more readable.

Signed-off-by: Matheus Tavares <matheus.bernardino@usp.br>
---
 builtin/clone.c | 27 +++++++++++++++++++--------
 1 file changed, 19 insertions(+), 8 deletions(-)

diff --git a/builtin/clone.c b/builtin/clone.c
index 50bde99618..862d2ea69c 100644
--- a/builtin/clone.c
+++ b/builtin/clone.c
@@ -392,6 +392,24 @@ static void copy_alternates(struct strbuf *src, struct strbuf *dst,
 	fclose(in);
 }
 
+static void mkdir_if_missing(const char *pathname, mode_t mode)
+{
+	/*
+	 * Create a dir at pathname unless there's already one.
+	 */
+	struct stat st;
+
+	if (mkdir(pathname, mode)) {
+		if (errno != EEXIST)
+			die_errno(_("failed to create directory '%s'"),
+				  pathname);
+		else if (stat(pathname, &st))
+			die_errno(_("failed to stat '%s'"), pathname);
+		else if (!S_ISDIR(st.st_mode))
+			die(_("%s exists and is not a directory"), pathname);
+	}
+}
+
 static void copy_or_link_directory(struct strbuf *src, struct strbuf *dest,
 				   const char *src_repo, int src_baselen)
 {
@@ -404,14 +422,7 @@ static void copy_or_link_directory(struct strbuf *src, struct strbuf *dest,
 	if (!dir)
 		die_errno(_("failed to open '%s'"), src->buf);
 
-	if (mkdir(dest->buf, 0777)) {
-		if (errno != EEXIST)
-			die_errno(_("failed to create directory '%s'"), dest->buf);
-		else if (stat(dest->buf, &buf))
-			die_errno(_("failed to stat '%s'"), dest->buf);
-		else if (!S_ISDIR(buf.st_mode))
-			die(_("%s exists and is not a directory"), dest->buf);
-	}
+	mkdir_if_missing(dest->buf, 0777);
 
 	strbuf_addch(src, '/');
 	src_len = src->len;
-- 
2.21.0.rc2.1.g2d5e20a900.dirty