1 files changed, 91 insertions, 0 deletions
diff --git a/builtin/check-ref-format.c b/builtin/check-ref-format.c
new file mode 100644
index 000000000000..bc67d3f0a83d
--- /dev/null
+++ b/builtin/check-ref-format.c
@@ -0,0 +1,91 @@
+/*
+ * 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 [--normalize] [<options>] <refname>\n"
+"   or: git check-ref-format --branch <branchname-shorthand>";
+
+/*
+ * Return a copy of refname but with leading slashes removed and runs
+ * of adjacent slashes replaced with single slashes.
+ *
+ * This function is similar to normalize_path_copy(), but stripped down
+ * to meet check_ref_format's simpler needs.
+ */
+static char *collapse_slashes(const char *refname)
+{
+	char *ret = xmallocz(strlen(refname));
+	char ch;
+	char prev = '/';
+	char *cp = ret;
+
+	while ((ch = *refname++) != '\0') {
+		if (prev == '/' && ch == prev)
+			continue;
+
+		*cp++ = ch;
+		prev = ch;
+	}
+	*cp = '\0';
+	return ret;
+}
+
+static int check_ref_format_branch(const char *arg)
+{
+	struct strbuf sb = STRBUF_INIT;
+	const char *name;
+	int nongit;
+
+	setup_git_directory_gently(&nongit);
+	if (strbuf_check_branch_ref(&sb, arg) ||
+	    !skip_prefix(sb.buf, "refs/heads/", &name))
+		die("'%s' is not a valid branch name", arg);
+	printf("%s\n", name);
+	strbuf_release(&sb);
+	return 0;
+}
+
+int cmd_check_ref_format(int argc, const char **argv, const char *prefix)
+{
+	int i;
+	int normalize = 0;
+	int flags = 0;
+	const char *refname;
+
+	if (argc == 2 && !strcmp(argv[1], "-h"))
+		usage(builtin_check_ref_format_usage);
+
+	if (argc == 3 && !strcmp(argv[1], "--branch"))
+		return check_ref_format_branch(argv[2]);
+
+	for (i = 1; i < argc && argv[i][0] == '-'; i++) {
+		if (!strcmp(argv[i], "--normalize") || !strcmp(argv[i], "--print"))
+			normalize = 1;
+		else if (!strcmp(argv[i], "--allow-onelevel"))
+			flags |= REFNAME_ALLOW_ONELEVEL;
+		else if (!strcmp(argv[i], "--no-allow-onelevel"))
+			flags &= ~REFNAME_ALLOW_ONELEVEL;
+		else if (!strcmp(argv[i], "--refspec-pattern"))
+			flags |= REFNAME_REFSPEC_PATTERN;
+		else
+			usage(builtin_check_ref_format_usage);
+	}
+	if (! (i == argc - 1))
+		usage(builtin_check_ref_format_usage);
+
+	refname = argv[i];
+	if (normalize)
+		refname = collapse_slashes(refname);
+	if (check_refname_format(refname, flags))
+		return 1;
+	if (normalize)
+		printf("%s\n", refname);
+
+	return 0;
+}