1 files changed, 71 insertions, 0 deletions
diff --git a/builtin-symbolic-ref.c b/builtin-symbolic-ref.c
new file mode 100644
index 0000000000..d41b40640b
--- /dev/null
+++ b/builtin-symbolic-ref.c
@@ -0,0 +1,71 @@
+#include "builtin.h"
+#include "cache.h"
+#include "refs.h"
+
+static const char git_symbolic_ref_usage[] =
+"git-symbolic-ref [-q] [-m <reason>] name [ref]";
+
+static void check_symref(const char *HEAD, int quiet)
+{
+	unsigned char sha1[20];
+	int flag;
+	const char *refs_heads_master = resolve_ref(HEAD, sha1, 0, &flag);
+
+	if (!refs_heads_master)
+		die("No such ref: %s", HEAD);
+	else if (!(flag & REF_ISSYMREF)) {
+		if (!quiet)
+			die("ref %s is not a symbolic ref", HEAD);
+		else
+			exit(1);
+	}
+	puts(refs_heads_master);
+}
+
+int cmd_symbolic_ref(int argc, const char **argv, const char *prefix)
+{
+	int quiet = 0;
+	const char *msg = NULL;
+
+	git_config(git_default_config);
+
+	while (1 < argc) {
+		const char *arg = argv[1];
+		if (arg[0] != '-')
+			break;
+		else if (!strcmp("-q", arg))
+			quiet = 1;
+		else if (!strcmp("-m", arg)) {
+			argc--;
+			argv++;
+			if (argc <= 1)
+				break;
+			msg = argv[1];
+			if (!*msg)
+				die("Refusing to perform update with empty message");
+			if (strchr(msg, '\n'))
+				die("Refusing to perform update with \\n in message");
+		}
+		else if (!strcmp("--", arg)) {
+			argc--;
+			argv++;
+			break;
+		}
+		else
+			die("unknown option %s", arg);
+		argc--;
+		argv++;
+	}
+
+	switch (argc) {
+	case 2:
+		check_symref(argv[1], quiet);
+		break;
+	case 3:
+		create_symref(argv[1], argv[2], msg);
+		break;
+	default:
+		usage(git_symbolic_ref_usage);
+	}
+	return 0;
+}