Initial QSfera import

Server/vendor/github.com/open-policy-agent/opa/v1/util/strings.go

@@ -0,0 +1,13 @@
+package util
+
+import "strings"
+
+// WithPrefix ensures that the string s starts with the given prefix.
+// If s already starts with prefix, it is returned unchanged.
+func WithPrefix(s, prefix string) string {
+	if strings.HasPrefix(s, prefix) {
+		return s
+	}
+
+	return prefix + s
+}