/**
 * Returns an absolute path based on a source location or the current working directory.
 *
 * @param string $to The target path.
 * @param string|null $from The source location. Defaults to the current working directory.
 * @param string $ds the directory separator to be used in the normalized result. Defaults to `DIRECTORY_SEPARATOR`.
 * @return string
 * @since 4.3.5
 */
public static function absolutePath(
    string $to,
    ?string $from = null,
    string $ds = DIRECTORY_SEPARATOR,
): string {
    $to = static::normalizePath($to, $ds);

    // Already absolute?
    if (
        str_starts_with($to, $ds) ||
        preg_match(sprintf('/^[A-Z]:%s/', preg_quote($ds, '/')), $to)
    ) {
        return $to;
    }

    if ($from === null) {
        $from = FileHelper::normalizePath(getcwd(), $ds);
    } else {
        $from = static::absolutePath($from, ds: $ds);
    }

    return $from . $ds . $to;
}

/**
 * Returns whether the given file path is located within or above any system directories.
 *
 * @param string $path
 * @return bool
 * @since 5.4.2
 */
public function isSystemDir(string $path): bool // $path = "../templates/poc"
{
    $path = FileHelper::absolutePath($path, '/'); // $path = "/var/www/html/web//../templates/poc"

    foreach (Craft::$app->getPath()->getSystemPaths() as $dir) {
        $dir = FileHelper::absolutePath($dir, '/'); // $dir = "/var/www/html/templates"
        if (str_starts_with("$path/", "$dir/") || str_starts_with("$dir/", "$path/")) { // if (false || false)
            return true;
        }
    }

    return false; // We're here!
}

/**
 * @param string $attribute
 * @param array|null $params
 * @param InlineValidator $validator
 * @return void
 * @since 4.4.6
 */
public function validatePath(string $attribute, ?array $params, InlineValidator $validator): void
{
    if (Craft::$app->getSecurity()->isSystemDir($this->getRootPath())) {
        $validator->addError($this, $attribute, Craft::t('app', 'Local filesystems cannot be located within or above system directories.'));
    }
}