WordPress/wp-includes/cache.php

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<?php
function wp_cache_add($key, $data, $flag = '', $expire = 0) {
global $wp_object_cache;
return $wp_object_cache->add($key, $data, $flag, $expire);
}
function wp_cache_close() {
global $wp_object_cache;
if ( ! isset($wp_object_cache) )
return;
return $wp_object_cache->save();
}
function wp_cache_delete($id, $flag = '') {
global $wp_object_cache;
return $wp_object_cache->delete($id, $flag);
}
function wp_cache_flush() {
global $wp_object_cache;
return $wp_object_cache->flush();
}
function wp_cache_get($id, $flag = '') {
global $wp_object_cache;
return $wp_object_cache->get($id, $flag);
}
function wp_cache_init() {
$GLOBALS['wp_object_cache'] =& new WP_Object_Cache();
}
function wp_cache_replace($key, $data, $flag = '', $expire = 0) {
global $wp_object_cache;
return $wp_object_cache->replace($key, $data, $flag, $expire);
}
function wp_cache_set($key, $data, $flag = '', $expire = 0) {
global $wp_object_cache;
return $wp_object_cache->set($key, $data, $flag, $expire);
}
define('CACHE_SERIAL_HEADER', "<?php\n/*");
define('CACHE_SERIAL_FOOTER', "*/\n?".">");
class WP_Object_Cache {
var $cache_dir;
var $cache_enabled = false;
var $expiration_time = 900;
var $flock_filename = 'wp_object_cache.lock';
var $mutex;
var $cache = array ();
var $dirty_objects = array ();
var $non_existant_objects = array ();
var $global_groups = array ('users', 'userlogins', 'usermeta');
var $blog_id;
var $cold_cache_hits = 0;
var $warm_cache_hits = 0;
var $cache_misses = 0;
var $secret = '';
function acquire_lock() {
// Acquire a write lock.
$this->mutex = @fopen($this->cache_dir.$this->flock_filename, 'w');
if ( false == $this->mutex)
return false;
flock($this->mutex, LOCK_EX);
return true;
}
function add($id, $data, $group = 'default', $expire = '') {
if (empty ($group))
$group = 'default';
if (false !== $this->get($id, $group, false))
return false;
return $this->set($id, $data, $group, $expire);
}
function delete($id, $group = 'default', $force = false) {
if (empty ($group))
$group = 'default';
if (!$force && false === $this->get($id, $group, false))
return false;
unset ($this->cache[$group][$id]);
$this->non_existant_objects[$group][$id] = true;
$this->dirty_objects[$group][] = $id;
return true;
}
function flush() {
if ( !$this->cache_enabled )
return true;
if ( ! $this->acquire_lock() )
return false;
$this->rm_cache_dir();
$this->cache = array ();
$this->dirty_objects = array ();
$this->non_existant_objects = array ();
$this->release_lock();
return true;
}
function get($id, $group = 'default', $count_hits = true) {
if (empty ($group))
$group = 'default';
if (isset ($this->cache[$group][$id])) {
if ($count_hits)
$this->warm_cache_hits += 1;
return $this->cache[$group][$id];
}
if (isset ($this->non_existant_objects[$group][$id]))
return false;
// If caching is not enabled, we have to fall back to pulling from the DB.
if (!$this->cache_enabled) {
if (!isset ($this->cache[$group]))
$this->load_group_from_db($group);
if (isset ($this->cache[$group][$id])) {
$this->cold_cache_hits += 1;
return $this->cache[$group][$id];
}
$this->non_existant_objects[$group][$id] = true;
$this->cache_misses += 1;
return false;
}
$cache_file = $this->cache_dir.$this->get_group_dir($group)."/".$this->hash($id).'.php';
if (!file_exists($cache_file)) {
$this->non_existant_objects[$group][$id] = true;
$this->cache_misses += 1;
return false;
}
// If the object has expired, remove it from the cache and return false to force
// a refresh.
$now = time();
if ((filemtime($cache_file) + $this->expiration_time) <= $now) {
$this->cache_misses += 1;
$this->delete($id, $group, true);
return false;
}
$this->cache[$group][$id] = unserialize(base64_decode(substr(@ file_get_contents($cache_file), strlen(CACHE_SERIAL_HEADER), -strlen(CACHE_SERIAL_FOOTER))));
if (false === $this->cache[$group][$id])
$this->cache[$group][$id] = '';
$this->cold_cache_hits += 1;
return $this->cache[$group][$id];
}
function get_group_dir($group) {
if (false !== array_search($group, $this->global_groups))
return $group;
return "{$this->blog_id}/$group";
}
function hash($data) {
if ( function_exists('hash_hmac') ) {
return hash_hmac('md5', $data, $this->secret);
} else {
return md5($data . $this->secret);
}
}
function load_group_from_db($group) {
global $wpdb;
if ('category' == $group) {
$this->cache['category'] = array ();
if ($dogs = $wpdb->get_results("SELECT * FROM $wpdb->categories")) {
foreach ($dogs as $catt)
$this->cache['category'][$catt->cat_ID] = $catt;
}
}
}
function make_group_dir($group, $perms) {
$group_dir = $this->get_group_dir($group);
$make_dir = '';
foreach (split('/', $group_dir) as $subdir) {
$make_dir .= "$subdir/";
if (!file_exists($this->cache_dir.$make_dir)) {
if (! @ mkdir($this->cache_dir.$make_dir))
break;
@ chmod($this->cache_dir.$make_dir, $perms);
}
if (!file_exists($this->cache_dir.$make_dir."index.php")) {
$file_perms = $perms & 0000666;
@ touch($this->cache_dir.$make_dir."index.php");
@ chmod($this->cache_dir.$make_dir."index.php", $file_perms);
}
}
return $this->cache_dir."$group_dir/";
}
function rm_cache_dir() {
$dir = $this->cache_dir;
$dir = rtrim($dir, DIRECTORY_SEPARATOR);
$top_dir = $dir;
$stack = array($dir);
$index = 0;
while ($index < count($stack)) {
# Get indexed directory from stack
$dir = $stack[$index];
$dh = @ opendir($dir);
if (!$dh)
return false;
while (($file = @ readdir($dh)) !== false) {
if ($file == '.' or $file == '..')
continue;
if (@ is_dir($dir . DIRECTORY_SEPARATOR . $file))
$stack[] = $dir . DIRECTORY_SEPARATOR . $file;
else if (@ is_file($dir . DIRECTORY_SEPARATOR . $file))
@ unlink($dir . DIRECTORY_SEPARATOR . $file);
}
$index++;
}
$stack = array_reverse($stack); // Last added dirs are deepest
foreach($stack as $dir) {
if ( $dir != $top_dir)
@ rmdir($dir);
}
}
function release_lock() {
// Release write lock.
flock($this->mutex, LOCK_UN);
fclose($this->mutex);
}
function replace($id, $data, $group = 'default', $expire = '') {
if (empty ($group))
$group = 'default';
if (false === $this->get($id, $group, false))
return false;
return $this->set($id, $data, $group, $expire);
}
function set($id, $data, $group = 'default', $expire = '') {
if (empty ($group))
$group = 'default';
if (NULL == $data)
$data = '';
$this->cache[$group][$id] = $data;
unset ($this->non_existant_objects[$group][$id]);
$this->dirty_objects[$group][] = $id;
return true;
}
function save() {
//$this->stats();
if (!$this->cache_enabled)
return true;
if (empty ($this->dirty_objects))
return true;
// Give the new dirs the same perms as wp-content.
$stat = stat(ABSPATH.'wp-content');
$dir_perms = $stat['mode'] & 0007777; // Get the permission bits.
$file_perms = $dir_perms & 0000666; // Remove execute bits for files.
// Make the base cache dir.
if (!file_exists($this->cache_dir)) {
if (! @ mkdir($this->cache_dir))
return false;
@ chmod($this->cache_dir, $dir_perms);
}
if (!file_exists($this->cache_dir."index.php")) {
@ touch($this->cache_dir."index.php");
@ chmod($this->cache_dir."index.php", $file_perms);
}
if ( ! $this->acquire_lock() )
return false;
// Loop over dirty objects and save them.
$errors = 0;
foreach ($this->dirty_objects as $group => $ids) {
$group_dir = $this->make_group_dir($group, $dir_perms);
$ids = array_unique($ids);
foreach ($ids as $id) {
$cache_file = $group_dir.$this->hash($id).'.php';
// Remove the cache file if the key is not set.
if (!isset ($this->cache[$group][$id])) {
if (file_exists($cache_file))
@ unlink($cache_file);
continue;
}
$temp_file = tempnam($group_dir, 'tmp');
$serial = CACHE_SERIAL_HEADER.base64_encode(serialize($this->cache[$group][$id])).CACHE_SERIAL_FOOTER;
$fd = @fopen($temp_file, 'w');
if ( false === $fd ) {
$errors++;
continue;
}
fputs($fd, $serial);
fclose($fd);
if (!@ rename($temp_file, $cache_file)) {
if (@ copy($temp_file, $cache_file))
@ unlink($temp_file);
else
$errors++;
}
@ chmod($cache_file, $file_perms);
}
}
$this->dirty_objects = array();
$this->release_lock();
if ( $errors )
return false;
return true;
}
function stats() {
echo "<p>";
echo "<strong>Cold Cache Hits:</strong> {$this->cold_cache_hits}<br/>";
echo "<strong>Warm Cache Hits:</strong> {$this->warm_cache_hits}<br/>";
echo "<strong>Cache Misses:</strong> {$this->cache_misses}<br/>";
echo "</p>";
foreach ($this->cache as $group => $cache) {
echo "<p>";
echo "<strong>Group:</strong> $group<br/>";
echo "<strong>Cache:</strong>";
echo "<pre>";
print_r($cache);
echo "</pre>";
if (isset ($this->dirty_objects[$group])) {
echo "<strong>Dirty Objects:</strong>";
echo "<pre>";
print_r(array_unique($this->dirty_objects[$group]));
echo "</pre>";
echo "</p>";
}
}
}
function WP_Object_Cache() {
return $this->__construct();
}
function __construct() {
global $blog_id;
register_shutdown_function(array(&$this, "__destruct"));
if (defined('DISABLE_CACHE'))
return;
if ( ! defined('ENABLE_CACHE') )
return;
// Disable the persistent cache if safe_mode is on.
if ( ini_get('safe_mode') && ! defined('ENABLE_CACHE') )
return;
if (defined('CACHE_PATH'))
$this->cache_dir = CACHE_PATH;
else
// Using the correct separator eliminates some cache flush errors on Windows
$this->cache_dir = ABSPATH.'wp-content'.DIRECTORY_SEPARATOR.'cache'.DIRECTORY_SEPARATOR;
if (is_writable($this->cache_dir) && is_dir($this->cache_dir)) {
$this->cache_enabled = true;
} else {
if (is_writable(ABSPATH.'wp-content')) {
$this->cache_enabled = true;
}
}
if (defined('CACHE_EXPIRATION_TIME'))
$this->expiration_time = CACHE_EXPIRATION_TIME;
if ( defined('WP_SECRET') )
$this->secret = WP_SECRET;
else
$this->secret = DB_PASSWORD . DB_USER . DB_NAME . DB_HOST . ABSPATH;
$this->blog_id = $this->hash($blog_id);
}
function __destruct() {
$this->save();
return true;
}
}
?>