1 files changed, 61 insertions, 0 deletions
diff --git a/builtin/check-ref-format.c b/builtin/check-ref-format.c
new file mode 100644
index 0000000000..b106c65d80
--- /dev/null
+++ b/builtin/check-ref-format.c
@@ -0,0 +1,61 @@
+/*
+ * GIT - The information manager from hell
+ */
+
+#include "cache.h"
+#include "refs.h"
+#include "builtin.h"
+#include "strbuf.h"
+
+static const char builtin_check_ref_format_usage[] =
+"git check-ref-format [--print] <refname>\n"
+"   or: git check-ref-format --branch <branchname-shorthand>";
+
+/*
+ * Replace each run of adjacent slashes in src with a single slash,
+ * and write the result to dst.
+ *
+ * This function is similar to normalize_path_copy(), but stripped down
+ * to meet check_ref_format's simpler needs.
+ */
+static void collapse_slashes(char *dst, const char *src)
+{
+	char ch;
+	char prev = '\0';
+
+	while ((ch = *src++) != '\0') {
+		if (prev == '/' && ch == prev)
+			continue;
+
+		*dst++ = ch;
+		prev = ch;
+	}
+	*dst = '\0';
+}
+
+int cmd_check_ref_format(int argc, const char **argv, const char *prefix)
+{
+	if (argc == 2 && !strcmp(argv[1], "-h"))
+		usage(builtin_check_ref_format_usage);
+
+	if (argc == 3 && !strcmp(argv[1], "--branch")) {
+		struct strbuf sb = STRBUF_INIT;
+
+		if (strbuf_check_branch_ref(&sb, argv[2]))
+			die("'%s' is not a valid branch name", argv[2]);
+		printf("%s\n", sb.buf + 11);
+		exit(0);
+	}
+	if (argc == 3 && !strcmp(argv[1], "--print")) {
+		char *refname = xmalloc(strlen(argv[2]) + 1);
+
+		if (check_ref_format(argv[2]))
+			exit(1);
+		collapse_slashes(refname, argv[2]);
+		printf("%s\n", refname);
+		exit(0);
+	}
+	if (argc != 2)
+		usage(builtin_check_ref_format_usage);
+	return !!check_ref_format(argv[1]);
+}