[POC PATCH 3/5] sha1_file_name_buf(): sha1_file_name in caller's buffer

[Thomas Rast <trast@student.ethz.ch>]

sha1_file_name is non-reentrant because of its use of a static buffer.
Split it into just the buffer writing (which can be called even from
threads as long as the buffer is stack'd) and a small wrapper that
uses the static buffer as before.

Signed-off-by: Thomas Rast <trast@student.ethz.ch>
---
 sha1_file.c |   29 +++++++++++++++++++----------
 1 files changed, 19 insertions(+), 10 deletions(-)

diff --git a/sha1_file.c b/sha1_file.c
index c3595b3..18648c3 100644
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -153,18 +153,11 @@ static void fill_sha1_path(char *pathbuf, const unsigned char *sha1)
 }
 
 /*
- * NOTE! This returns a statically allocated buffer, so you have to be
- * careful about using it. Do an "xstrdup()" if you need to save the
- * filename.
- *
- * Also note that this returns the location for creating.  Reading
- * SHA1 file can happen from any alternate directory listed in the
- * DB_ENVIRONMENT environment variable if it is not found in
- * the primary object database.
+ * Similar to sha1_file_name but you provide a buffer of size at least
+ * PATH_MAX.
  */
-char *sha1_file_name(const unsigned char *sha1)
+void sha1_file_name_buf(char *buf, const unsigned char *sha1)
 {
-	static char buf[PATH_MAX];
 	const char *objdir;
 	int len;
 
@@ -179,6 +172,22 @@ char *sha1_file_name(const unsigned char *sha1)
 	buf[len+3] = '/';
 	buf[len+42] = '\0';
 	fill_sha1_path(buf + len + 1, sha1);
+}
+
+/*
+ * NOTE! This returns a statically allocated buffer, so you have to be
+ * careful about using it. Do an "xstrdup()" if you need to save the
+ * filename.
+ *
+ * Also note that this returns the location for creating.  Reading
+ * SHA1 file can happen from any alternate directory listed in the
+ * DB_ENVIRONMENT environment variable if it is not found in
+ * the primary object database.
+ */
+char *sha1_file_name(const unsigned char *sha1)
+{
+	static char buf[PATH_MAX];
+	sha1_file_name_buf(buf, sha1);
 	return buf;
 }
 
-- 
1.7.8.431.g2abf2