Counter.php

<?php

class Counter{
    private $counterFileName;

    public function __construct($inFN){
        if(!file_exists($inFN)){
            $counterFilePointer = fopen($inFN, 'w');
            flock($counterFilePointer, LOCK_EX);
            fwrite($counterFilePointer, '0');
            flock($counterFilePointer, LOCK_UN);
            fclose($counterFilePointer);
        }
        $this->counterFileName = $inFN;
    }
    public function getCount(){
        if($counterFilePointer = fopen($this->counterFileName, 'r')){
            flock($counterFilePointer, LOCK_SH);
            $count = (int)fgets($counterFilePointer);
            flock($counterFilePointer, LOCK_UN);
            fclose($counterFilePointer);
            return $count;
        }else{
            throw new Exception("ファイルオープン失敗");
        }
    }
    public function incrementCount($val = 1){
        $count = $this->getCount() + $val;
        if($counterFilePointer = fopen($this->counterFileName, 'w')){
            flock($counterFilePointer, LOCK_EX);
            fwrite($counterFilePointer, $count);
            flock($counterFilePointer, LOCK_UN);
            fclose($counterFilePointer);
            return $count;
        }else{
            throw new Exception("ファイルオープン失敗");
        }
    }
}