sha1-name: pass len argument to interpret_branch_name()

This is useful to make sure we don't step outside the boundaries of what
we are interpreting at the moment. For example while interpreting
foobar@{u}~1, the job of interpret_branch_name() ends right before ~1,
but there's no way to figure that out inside the function, unless the
len argument is passed.

So let's do that.

Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

cache.h

@@ -893,7 +893,7 @@ extern char *resolve_refdup(const char *ref, unsigned char *sha1, int reading, i
 
 extern int dwim_ref(const char *str, int len, unsigned char *sha1, char **ref);
 extern int dwim_log(const char *str, int len, unsigned char *sha1, char **ref);
-extern int interpret_branch_name(const char *str, struct strbuf *);
+extern int interpret_branch_name(const char *str, int len, struct strbuf *);
 extern int get_sha1_mb(const char *str, unsigned char *sha1);
 
 extern int refname_match(const char *abbrev_name, const char *full_name, const char **rules);

refs.c

@@ -1951,7 +1951,7 @@ static int remove_empty_directories(const char *file)
 static char *substitute_branch_name(const char **string, int *len)
 {
 	struct strbuf buf = STRBUF_INIT;
-	int ret = interpret_branch_name(*string, &buf);
+	int ret = interpret_branch_name(*string, *len, &buf);
 
 	if (ret == *len) {
 		size_t size;

revision.c

@@ -200,7 +200,7 @@ static void add_pending_object_with_mode(struct rev_info *revs,
 		revs->no_walk = 0;
 	if (revs->reflog_info && obj->type == OBJ_COMMIT) {
 		struct strbuf buf = STRBUF_INIT;
-		int len = interpret_branch_name(name, &buf);
+		int len = interpret_branch_name(name, 0, &buf);
 		int st;
 
 		if (0 < len && name[len] && buf.len)

sha1_name.c

@@ -1012,7 +1012,7 @@ static int reinterpret(const char *name, int namelen, int len, struct strbuf *bu
 	int ret;
 
 	strbuf_add(buf, name + len, namelen - len);
-	ret = interpret_branch_name(buf->buf, &tmp);
+	ret = interpret_branch_name(buf->buf, buf->len, &tmp);
 	/* that data was not interpreted, remove our cruft */
 	if (ret < 0) {
 		strbuf_setlen(buf, used);
@@ -1046,14 +1046,16 @@ static int reinterpret(const char *name, int namelen, int len, struct strbuf *bu
  * If the input was ok but there are not N branch switches in the
  * reflog, it returns 0.
  */
-int interpret_branch_name(const char *name, struct strbuf *buf)
+int interpret_branch_name(const char *name, int namelen, struct strbuf *buf)
 {
 	char *cp;
 	struct branch *upstream;
-	int namelen = strlen(name);
 	int len = interpret_nth_prior_checkout(name, buf);
 	int tmp_len;
 
+	if (!namelen)
+		namelen = strlen(name);
+
 	if (!len) {
 		return len; /* syntax Ok, not enough switches */
 	} else if (len > 0) {
@@ -1100,7 +1102,7 @@ int interpret_branch_name(const char *name, struct strbuf *buf)
 int strbuf_branchname(struct strbuf *sb, const char *name)
 {
 	int len = strlen(name);
-	int used = interpret_branch_name(name, sb);
+	int used = interpret_branch_name(name, len, sb);
 
 	if (used == len)
 		return 0;