导出或导入 memcached 的数据

<?php

function memcachedump_usage() {
    echo "Usage: memcachedump\n";
    echo "       -h host      server host, default localhost\n";
    echo "       -p port      server port, default 11211\n";
    echo "       -f filename  dump to file, default STDOUT\n";
    echo "       -i           import from file\n";
    echo "       --prefix     key prefix\n";
}

function memcachedump_description() {
    return "导出／导入 memcached 的数据";
}

function memcachedump_entrance($argv) {
    $args = args_parse($argv);
    $is_import = isset($args['i']) ? true : false;
    $mc = memcachedump_connect(isset($args['h']) ? $args['h'] : 'localhost', isset($args['p']) ? $args['p'] : 11211);
    if (!$mc) {
        fwrite(STDERR, "connect memcache error\n");
        exit();
    }
    if (isset($args['f'])) {
        $file = fopen($args['f'], $is_import ? 'rb' : 'ab');
        if (false === $file) {
            fwrite(STDERR, "can not open file {$file}\n");
            exit();
        }
    } else {
        $file = STDOUT;
    }
    $prefix = isset($args['prefix']) ? $args['prefix'] : '';
    if ($is_import) {
        memcachedump_import($mc, $file, $prefix);
    } else {
        memcachedump_dump($mc, $file, $prefix);
    }
    fclose($file);
    echo "\ndone.\n";
}

function memcachedump_connect($host, $port, $timeout = 1) {
    static $pool = array();
    if (!isset($pool["{$host}:{$port}"])) {
        $mc = new Memcache();
        if ($mc->connect($host, $port, $timeout)) {
            $pool["{$host}:{$port}"] = $mc;
        } else {
            return null;
        }
    }
    return $pool["{$host}:{$port}"];
}

function pack2DWord($n) {
    $a = (0xFF000000 & $n) >> 24;
    $b = (0x00FF0000 & $n) >> 16;
    $c = (0x0000FF00 & $n) >> 8;
    $d = 0x000000FF & $n;
    return pack('CCCC', $a, $b, $c, $d);
}

function unpackDWord($s) {
    $a = (0xFFFFFFFF & ord($s{0})) << 24;
    $b = (0xFFFFFFFF & ord($s{1})) << 16;
    $c = (0xFFFFFFFF & ord($s{2})) << 8;
    $d = ord($s{3});
    return $a + $b + $c + $d;
}

/**
 * 
 * @param \Memcache $mc
 * @param type $file
 * @param type $prefix
 */
function memcachedump_dump($mc, $file, $prefix) {
    $server_slabs = $mc->getExtendedStats('slabs');
    foreach ($server_slabs as $server => $slabs) {
        foreach ($slabs as $slab_id => $slab_meta) {
            if (!is_int($slab_id)) {
                continue;
            }
            $dump = $mc->getExtendedStats('cachedump', (int)$slab_id, (int)$slab_meta['used_chunks']);
            foreach ($dump as $server => $entries) {
                if (!$entries) {
                    continue;
                }
                foreach ($entries as $key => $meta) {
                    if ($prefix && ($prefix !== substr($key, 0, strlen($prefix)))) {
                        continue;
                    }
                    $val = $mc->get($key);
                    if (empty($val)) {
                        continue;
                    }
                    $kl = pack2DWord(strlen($key));
                    $vl = pack2DWord((int)$meta[0]);
                    fwrite($file, "{$kl}{$vl}{$key}{$val}");
                }
            }
        }
    }
}

/**
 * 
 * @param \MemCache $mc
 * @param type $file
 */
function memcachedump_import($mc, $file) {
    while (!feof($file)) {
        $ks = fread($file, 4);
        if (feof($file) || !isset($ks{3})) {
            continue;
        }
        $vs = fread($file, 4);
        if (feof($file) || !isset($vs{3})) {
            continue;
        }
        $kl = unpackDWord($ks);
        $vl = unpackDWord($vs);
        if (($kl <= 0) || ($vl <= 0)) {
            continue;
        }
        $key = fread($file, $kl);
        if (feof($file)) {
            continue;
        }
        $val = fread($file, $vl);
        if (empty($val)) {
            continue;
        }
        $mc->set($key, $val);
    }
}

/**
 * 解释参数，可以解释以下类型：
 *     -p
 *     -pVALUE
 *     -p value
 *     --param value
 *     -p=value
 *     --param=value
 *     param=value
 * @param array $argv
 * @return array
 */
function args_parse($argv) {
    if (!is_array($argv) || empty($argv)) {
        return array();
    }
    $argc = count($argv);
    $ret = array();
    for ($i = 0; $i < $argc; ++$i) {
        $arg = $argv[$i];
        if (strpos($arg, '=') > 0) { // -p=value --param=value param=value
            list($arg_name, $arg_value) = explode('=', ltrim($arg, '-'), 2);
            $ret[$arg_name] = $arg_value;
            continue;
        }
        if ($arg{0} !== '-') {
            continue;
        }
        if (($arg{1} !== '-') && isset($arg{2})) {// -pVALUE
            $ret[$arg{1}] = substr($arg, 2);
            continue;
        } else if (isset($argv[$i + 1]) && ($argv[$i + 1]{0} !== '-') && (false === strpos($arg, '='))) {
            $ret[ltrim($arg, '-')] = $argv[$i + 1];
            ++$i;
        } else {
            $ret[ltrim($arg, '-')] = true;
        }
    }
    return $ret;
}