FileCache.php

<?php
namespace QMTV\System;

/**
 * Class FileCache
 *
 * @author  liuzhen
 */
class FileCache
{
    protected $sCachePath;
    protected $mCBKey2File;

    /**
     * @param string $sCacheDir
     * @param int    $iCreateMode
     * @param mixed  $mCBKey2File
     *
     * @throws \RuntimeException
     */
    public function __construct($sCacheDir, $iCreateMode = 0777, $mCBKey2File = null)
    {
        $this->sCachePath = rtrim($sCacheDir, '/') . '/';
        if (!file_exists($this->sCachePath)) {
            if (!@mkdir($this->sCachePath, $iCreateMode, true)) {
                throw new \RuntimeException("[CACHE] ; Create dir[$sCacheDir] failed");
            }
        }
        $this->mCBKey2File = $mCBKey2File;
    }

    /**
     * @param string $sKey
     *
     * @return array [<mixed>data, <bool>has_out_date, <string>file_path]
     */
    public function get($sKey)
    {
        return $this->getWithDetailInfo($sKey)[0];
    }

    public function getWithDetailInfo($sKey)
    {
        $sFile = $this->getFilePath($sKey);

        if (!file_exists($sFile)) {
            return [null, 0, true, $sFile];
        }

        $aData = file($sFile);
        if (count($aData) !== 2) {
            return [null, 0, true, $sFile];
        }

        $iExpireAT = (int)$aData[0];
        return [json_decode($aData[1]), $iExpireAT, time() - $iExpireAT > 0, $sFile];
    }

    /**
     * @param string $sKey
     * @param mixed  $mValue
     * @param int    $iExpire
     *
     * @return bool
     */
    public function set($sKey, $mValue, $iExpire)
    {
        $sFile = $this->getFilePath($sKey);
        return (bool)file_put_contents($sFile, sprintf("%d\n%s", time() + $iExpire, json_encode($mValue)), LOCK_EX);
    }

    /**
     * @param $sKey
     *
     * @return bool
     */
    public function delete($sKey)
    {
        $sFile = $this->sCachePath . md5($sKey);
        return file_exists($sFile) ? unlink($sFile) : true;
    }

    /**
     * @return bool
     */
    public function flush()
    {
        $rDir = opendir($this->sCachePath);
        while (($sFile = readdir($rDir)) !== false) {
            if (ltrim($sFile, '.') !== '') {
                unlink($this->sCachePath . $sFile);
            }
        }
        closedir($rDir);
        return true;
    }

    protected function getFilePath($sKey)
    {
        return $this->sCachePath . ($this->mCBKey2File === null ? md5($sKey) : call_user_func($this->mCBKey2File,
            $sKey));
    }

    public static function getAndSetFromFileCache(
        FileCache $FileCache,
        $sKey,
        $iExpire,
        $iExpireEffect,
        $mCB,
        $aParam = []
    ) {
        list($mData, $iExpireAt, $bHasOutDate, $sFile) = $FileCache->getWithDetailInfo($sKey);
        # 未过期
        if (!$bHasOutDate) {
            return $mData;
        }

        # 已过期
        $sLockFile = $sFile . '.lock';
        $rF        = fopen($sLockFile, 'w');
        # 未拿到锁
        if (!flock($rF, LOCK_EX | LOCK_NB)) {
            if ($iExpireAt == 0 || $iExpireAt + $iExpireEffect < time()) {
                # 过期不可用($iExpireAt + $this->iExpireEffect < time()) / 不存在($iExpireAt == 0) 返回空
                $FileCache->delete($sKey);
                return null;
            } else {
                # 过期可用 返回 old 数据
                return $mData;
            }
        }
        # 拿到锁, 取数据更新
        $mData = call_user_func_array($mCB, $aParam);
        if ($mData !== null) {
            $FileCache->set($sKey, $mData, $iExpire);
        }
        flock($rF, LOCK_UN);
        fclose($rF);

        return $mData;
    }
}