<?php

if (!defined('_DIR_TMP')) define('_DIR_TMP', 'tmp/');
if (!defined('_DIR_CACHE_FILECACHE')) {
	if (defined('_DIR_FILECACHE')) define('_DIR_CACHE_FILECACHE', _DIR_TMP._DIR_FILECACHE); // compat
	elseif(defined('_DIR_CACHE')) define('_DIR_CACHE_FILECACHE', _DIR_CACHE);
	else define('_DIR_CACHE_FILECACHE', _DIR_TMP.'cache/');
}

class MCacheBackend_filecache extends MCacheBackend {

	// file named tmp/cache/ab/cd
	// that's a maximum of 16^4 files in 256 directories
	function filename($u) {
		$u = md5($u);
		$d = substr($u,0,2); 
		$u = substr($u,2,2);
	
		# SPIP
		if (function_exists('sous_repertoire')) {
			$rep = _DIR_CACHE_FILECACHE;
			if(!@file_exists(_DIR_CACHE_FILECACHE)) {
				$rep = sous_repertoire(_DIR_CACHE_FILECACHE, '');
			}
			return sous_repertoire($rep,$d) . $u;
		}
	
		# Normal PHP
		if (!is_dir(_DIR_CACHE_FILECACHE))
			@mkdir(_DIR_CACHE_FILECACHE);
		if (!is_dir($sub = _DIR_CACHE_FILECACHE.$d))
			@mkdir($sub);
		return $sub.'/'.$u;
	}
	
	function get($key) {
		if ($c = @file_get_contents($this->filename($key))
		AND $r = unserialize($c)
		AND $r[1] === $key
		AND $r[2] >= time())
			return $r[0];
	}
	
	function set($key, $value, $ttl=null) {
		$r = array($value);
		$r[1] = $key;
		$r[2] = isset($ttl)
			? time() + intval($ttl)
			: time() + 365*24*3600;
	
		return (
			$f = $this->filename($key)
			AND $n = @tempnam(dirname($f), 'xc')
			AND $h = @fopen($n, 'w')
			AND @fwrite($h, serialize($r))
			AND @fclose($h)
			AND @rename($n, $f)
		);
	}
	
	function exists($key) {
		if ($c = @file_get_contents($this->filename($key))
		AND $r = @unserialize($c)
		AND $r[1] == $key
		AND $r[2] >= time())
			return true;
		else
			return false;
	}
	
	function del($key) {
		return (
			$c = @file_get_contents($f = $this->filename($key))
			AND $s = supprimer_fichier($f)
			AND $r = @unserialize($c)
			AND $r[1] == $key
			AND $r[2] >= time()
		);
	}
	
	function inc($key, $value=null, $ttl=null) {
		$this->lock($key);
		$value = (isset($value) ? intval($value) : 1) + intval($this->get($key));
		$this->set($key, $value);
		$this->unlock($key);
		return $value;
	}
	
	function dec($key, $value=null, $ttl=null) {
		$value = isset($value) ? intval($value) : 1;
		return $this->inc($key, -$value, $ttl);
	}
	
	function lock($key, /* private */ $unlock=false) {
		static $locks = array();
		$f = $this->filename($key);
	
		/* unlock */
		if ($unlock) {
			if (isset($locks[$f])
			AND is_resource($locks[$f])) {
				@flock($locks[$f], LOCK_UN);
				@fclose($locks[$f]);
				unset($locks[$f]);
			}
		}
		/* lock */
		else {
			if (!isset($locks[$f])) {
				$locks[$f] = @fopen($f, 'a');
				@flock($locks[$f], LOCK_EX);
				return true;
			}
		}
	}
	
	function unlock($key) {
		$this->lock($key, true);
	}
	
	function size() {
		# check dirs until we reach > 500 files
		$t = 0;
		$n = 0;
		$time = (isset($GLOBALS['meta']['cache_mark'])?$GLOBALS['meta']['cache_mark']:0);
		for($i=0;$i<256;$i++) {
			$dir = _DIR_CACHE.sprintf('%02s', dechex($i));
			if (@is_dir($dir) AND is_readable($dir) AND $d = @opendir($dir)) {
				while (($f = readdir($d)) !== false) {
					if (preg_match(',^[0-9a-f][0-9a-f]$,S', $f)
					AND $a = stat("$dir/$f")) {
						$n++;
						if ($a['mtime'] >= $time) {
							if ($a['blocks'] > 0)
								$t += 512*$a['blocks'];
							else
								$t += $a['size'];
						}
					}
				}
			}
			if ($n>500)
				return intval(256*$t/(1+$i));
		}
		return $t;
	}
}