复制代码 代码如下:

<?php

/**

* @usage: used to offer safe file write operation in multiple threads context, arbitory file type

* @author: Rocky Zhang

* @time: Nov. 11 2009

* @demo[0]: $handler = mfopen($file, 'a+');

* mfwrite($handler, $str);

*/

function mfopen($file, $mode='w+') {

$tempfile = generateTempfile('./tempdir', $file);

preg_match('/b/i', $mode) || ($mode .= 'b'); // 'b' is recommended

if (preg_match('/w|a/i', $mode) && !is_writable($file)) {

exit("{$file} is not writable!");

}

$filemtime = $filemtime2 = 0;

$tempdir = dirname($tempfile);

is_dir($tempdir) || mkdir($tempdir, 0777);

do { // do-while used to avoid modify in a long time copy

clearstatcache();

$filemtime = filemtime($file);

copy($file, $tempfile);

$filemtime2 = filemtime($file);

} while ( ($filemtime2 - $filemtime) != 0 );

if (!$handler = fopen($tempfile, $mode)) {

exit('Fail on opening tempfile, write authentication is must on temporary dir!');

}

return array(0=>$handler, 1=>$filemtime, 2=>$file, 3=>$tempfile, 4=>$mode);

}

// I do think that this function should be optimized further

function mfwrite(&$handler, $str='') {

if (strlen($str) > 0) {

$num = fwrite($handler[0], $str);

fflush($handler[0]);

}

clearstatcache();

$mtime = filemtime($handler[2]);

if ( $mtime == $handler[1] ) { // compare between source file and temporary file

if ( $num && $num > 0 ) { // temporary file has been updated, copy to source file

copy($handler[3], $handler[2]) || exit;

$handler[1] = filemtime($handler[3]);

touch($handler[2], $handler[1], $handler[1]);

}

} else { // source file has been modified, load source file to temporary file

copy($handler[2], $handler[3]) || exit;

touch($handler[3], $mtime, $mtime);

$handler[1] = $mtime;

}

}

function generateTempfile($tempdir='tempdir', $file) {

$rand = md5(microtime());

return "{$tempdir}/{$rand}_".$file;

}

?>