update

inc/virtio-helpers.inc

@@ -23,3 +23,17 @@ TAPM_VIRTIO_LABELED_FILENAME() {
 
 	printf 'virtio-win-%s%s.iso\n' "$label" "${version:+-${version}}"
 }
+
+TAPM_VIRTIO_CACHE_VALID() {
+	local checked_at="${1:-}"
+	local now="${2:-}"
+	local max_age="${3:-}"
+	local filename="${4:-}"
+
+	[[ "$checked_at" =~ ^[0-9]+$ &&
+		"$now" =~ ^[0-9]+$ &&
+		"$max_age" =~ ^[1-9][0-9]*$ &&
+		"$filename" =~ ^virtio-win(-[0-9]+\.[0-9]+\.[0-9]+)?\.iso$ ]] ||
+		return 1
+	(( now >= checked_at && now - checked_at < max_age ))
+}