strbuf_branchname(): a wrapper for branch name shorthands

The function takes a user-supplied string that is supposed to be a branch
name, and puts it in a strbuf after expanding possible shorthand notation.

A handful of open coded sequence to do this in the existing code have been
changed to use this helper function.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

branch.c

@@ -134,13 +134,8 @@ void create_branch(const char *head,
 	char *real_ref, msg[PATH_MAX + 20];
 	struct strbuf ref = STRBUF_INIT;
 	int forcing = 0;
-	int len;
 
-	len = strlen(name);
-	if (interpret_branch_name(name, &ref) != len) {
-		strbuf_reset(&ref);
-		strbuf_add(&ref, name, len);
-	}
+	strbuf_branchname(&ref, name);
 	strbuf_splice(&ref, 0, 0, "refs/heads/", 11);
 
 	if (check_ref_format(ref.buf))

builtin-branch.c

@@ -121,11 +121,7 @@ static int delete_branches(int argc, const char **argv, int force, int kinds)
 			die("Couldn't look up commit object for HEAD");
 	}
 	for (i = 0; i < argc; i++, strbuf_release(&bname)) {
-		int len = strlen(argv[i]);
-
-		if (interpret_branch_name(argv[i], &bname) != len)
-			strbuf_add(&bname, argv[i], len);
-
+		strbuf_branchname(&bname, argv[i]);
 		if (kinds == REF_LOCAL_BRANCH && !strcmp(head, bname.buf)) {
 			error("Cannot delete the branch '%s' "
 			      "which you are currently on.", bname.buf);

builtin-checkout.c

@@ -353,16 +353,11 @@ struct branch_info {
 static void setup_branch_path(struct branch_info *branch)
 {
 	struct strbuf buf = STRBUF_INIT;
-	int ret;
 
-	if ((ret = interpret_branch_name(branch->name, &buf))
-	    && ret == strlen(branch->name)) {
+	strbuf_branchname(&buf, branch->name);
+	if (strcmp(buf.buf, branch->name))
 		branch->name = xstrdup(buf.buf);
-		strbuf_splice(&buf, 0, 0, "refs/heads/", 11);
-	} else {
-		strbuf_addstr(&buf, "refs/heads/");
-		strbuf_addstr(&buf, branch->name);
-	}
+	strbuf_splice(&buf, 0, 0, "refs/heads/", 11);
 	branch->path = strbuf_detach(&buf, NULL);
 }
 

builtin-merge.c

@@ -360,9 +360,8 @@ static void merge_name(const char *remote, struct strbuf *msg)
 	const char *ptr;
 	int len, early;
 
-	len = strlen(remote);
-	if (interpret_branch_name(remote, &bname) == len)
-		remote = bname.buf;
+	strbuf_branchname(&bname, remote);
+	remote = bname.buf;
 
 	memset(branch_head, 0, sizeof(branch_head));
 	remote_head = peel_to_type(remote, 0, NULL, OBJ_COMMIT);

strbuf.c

@@ -357,3 +357,12 @@ int strbuf_read_file(struct strbuf *sb, const char *path, size_t hint)
 
 	return len;
 }
+
+int strbuf_branchname(struct strbuf *sb, const char *name)
+{
+	int len = strlen(name);
+	if (interpret_branch_name(name, sb) == len)
+		return 0;
+	strbuf_add(sb, name, len);
+	return len;
+}

strbuf.h

@@ -131,4 +131,6 @@ extern int strbuf_getline(struct strbuf *, FILE *, int);
 extern void stripspace(struct strbuf *buf, int skip_comments);
 extern int launch_editor(const char *path, struct strbuf *buffer, const char *const *env);
 
+extern int strbuf_branchname(struct strbuf *sb, const char *name);
+
 #endif /* STRBUF_H */