PHP: Count the lines of a file

PHP: count file lines

public function countLines($filePath, $emptyLines = true) {
    $lineCounts = 0;
    if (is_file($filePath) == true) {
        $fileHandle = fopen($filePath, 'r');
        if ($fileHandle == true) {
            while(feof($fileHandle) == false) {
                $currentLine = fgets($fileHandle);
                if ($emptyLines == false) {
                    if (trim($currentLine) != null) {
                        $lineCounts = $lineCounts + 1;
                    }
                } else {
                    $lineCounts = $lineCounts + 1;
                }
            }
        }
        fclose($fileHandle);
    }
    return $lineCounts;
}