sync.php

<?php
$fDone = $_GET['fDone'];
$fSynced = $_GET['fSynced'];

$fDone = file('generatedFiles/' . $fDone);
$fSynced = file('generatedFiles/' . $fSynced);

$fNumDone = count($fDone);
$fNumSynced = count($fSynced);

$filename = 'generatedFiles/' . $_GET['fDone'];




$breakLine = TRUE;
if($fNumDone <= $fNumSynced + 2){
	$fh = fopen($filename, 'r');
	$line = 1;
	while (($buffer = fgets($fh)) !== FALSE) {
		if ($line == $fNumSynced + 1) {
			
			$breakLine = FALSE;
	       	if(strpos($buffer, "\n"))
	       		$breakLine = TRUE;
		    	
	       break;
	   }   
	   $line++;
	}
}



if(($fNumDone && $fNumDone != $fNumSynced && $breakLine)){

	$filename = 'generatedFiles/' . $_GET['fSynced'];
	echo $fDone[$fNumSynced];


	$fp = fopen('generatedFiles/' . $_GET['fSynced'], 'a'); 

	flock($fp,LOCK_SH); 

	if(is_writable('generatedFiles/' . $_GET['fSynced']))
		$written = fputs($fp, $fDone[$fNumSynced]); 

	fclose($fp); 
}