less auto compile in Zend Framework 1.12

Zend Less

protected function _initCss(){
    require_once APPLICATION_PATH . "/../library/lessphp/lessc.inc.php";


    $inputFile = APPLICATION_PATH."/../public/css/less/style.less";
    $outputFile  = APPLICATION_PATH."/../public/css/style.css";

    // load the cache
    $cacheFile = APPLICATION_PATH . "/../data/cache/css-compiled.less.cache";

    if (file_exists($cacheFile)) {
        $cache = unserialize(file_get_contents($cacheFile));
    } else {
        $cache = $inputFile;
    }

    $less = new lessc;
    $newCache = $less->cachedCompile($cache);

    if (!is_array($cache) || $newCache["updated"] > $cache["updated"]) {
        file_put_contents($cacheFile, serialize($newCache));
        file_put_contents($outputFile, $newCache['compiled']);
    }
}