CacheDriverTrait.php: add CacheDriverTrait to share code

inc/Data/Driver/CacheDriverTrait.php

@@ -0,0 +1,20 @@
+<?php
+namespace Vichan\Data\Driver;
+
+
+trait CacheDriverTrait {
+	/**
+	 * Tries to interpret the uri as a path to a unix socket.
+	 *
+	 * @param string $uri
+	 * @return ?string The path to the socket, null if it cannot be interpreted as such.
+	 */
+	private static function asUnixSocketPath(string $uri): ?string {
+		if (str_starts_with($uri, 'unix:')) {
+			return \substr($uri, 5);
+		} elseif (str_starts_with($uri, ':')) {
+			return \substr($uri, 1);
+		}
+		return null;
+	}
+}