PHP simple object cache

<?php
$_cachetime = 3600;
$_cacheroot = '/path/to/cache/';
function cacheget($key) {
	global $_cachetime, $_cacheroot;
	$_cachename = sprintf('%x', crc32($key));
	$_cachefolder = $_cacheroot.substr($_cachename,0,2).'/';
	$_cachefile = $_cachefolder.$_cachename;
	if (file_exists($_cachefile) && (filemtime($_cachefile) > time() - $_cachetime || 
		(file_exists($_cachefile.'.lock') && time() - filemtime($_cachefile.'.lock') < 120))) {
		return unserialize(file_get_contents($_cachefile));
	}
	return false;
}
function cachelock($key) {
	global $_cacheroot;
	$_cachename = sprintf("%x", crc32($key));
	$_cachefolder = $_cacheroot.substr($_cachename,0,2).'/';
	$_cachefile = $_cachefolder.$_cachename;
	umask(0);
	if (!file_exists($_cachefolder)) {
		mkdir($_cachefolder,0777);
	}
	touch($_cachefile.'.lock');
}
function cacheset($key, $value) {
	global $_cacheroot;
	$_cachename = sprintf('%x', crc32($key));
	$_cachefolder = $_cacheroot.substr($_cachename,0,2).'/';
	$_cachefile = $_cachefolder.$_cachename;
	umask(0);
	if (!file_exists($_cachefolder)) {
		mkdir($_cachefolder,0777);
	}
	if ($_h = fopen($_cachefile, 'w')) {
		fwrite($_h, serialize($value));
		fclose($_h);
		unlink($_cachefile.'.lock');
	}
}
?>

<?php
$query = 'SELECT * FROM table';
$sql = mysql_query($query);
while ($row = mysql_fetch_assoc($sql)) {
        var_dump($row);
}
?>

<?php
$query = 'SELECT * FROM table';
if (!$rows = cacheget($query)) {
        cachelock($query);
        $sql = mysql_query($query);
        $rows = array();
        while ($row = mysql_fetch_assoc($sql))
                $rows[] = $row;
        cacheset($query, $rows);
}
foreach($rows as $row) {
        var_dump($row);
}
?>