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<?php
/**
* Generic class to handle caching
*
* @license GPL 2 (http://www.gnu.org/licenses/gpl.html)
* @author Chris Smith <chris@jalakai.co.uk>
*/
if(!defined('DOKU_INC')) define('DOKU_INC',fullpath(dirname(__FILE__).'/../').'/');
require_once(DOKU_INC.'inc/io.php');
require_once(DOKU_INC.'inc/pageutils.php');
require_once(DOKU_INC.'inc/parserutils.php');
class cache {
var $key = ''; // primary identifier for this item
var $ext = ''; // file ext for cache data, secondary identifier for this item
var $cache = ''; // cache file name
var $depends = array(); // array containing cache dependency information,
// used by _useCache to determine cache validity
var $_event = ''; // event to be triggered during useCache
function cache($key,$ext) {
$this->key = $key;
$this->ext = $ext;
$this->cache = getCacheName($key,$ext);
}
/**
* public method to determine whether the cache can be used
*
* to assist in cetralisation of event triggering and calculation of cache statistics,
* don't override this function override _useCache()
*
* @param array $depends array of cache dependencies, support dependecies:
* 'age' => max age of the cache in seconds
* 'files' => cache must be younger than mtime of each file
* (nb. dependency passes if file doesn't exist)
*
* @return bool true if cache can be used, false otherwise
*/
function useCache($depends=array()) {
$this->depends = $depends;
$this->_addDependencies();
if ($this->_event) {
return $this->_stats(trigger_event($this->_event,$this,array($this,'_useCache')));
} else {
return $this->_stats($this->_useCache());
}
}
/**
* private method containing cache use decision logic
*
* this function processes the following keys in the depends array
* purge - force a purge on any non empty value
* age - expire cache if older than age (seconds)
* files - expire cache if any file in this array was updated more recently than the cache
*
* can be overridden
*
* @return bool see useCache()
*/
function _useCache() {
if (!empty($this->depends['purge'])) return false; // purge requested?
if (!($this->_time = @filemtime($this->cache))) return false; // cache exists?
// cache too old?
if (!empty($this->depends['age']) && ((time() - $this->_time) > $this->depends['age'])) return false;
if (!empty($this->depends['files'])) {
foreach ($this->depends['files'] as $file) {
if ($this->_time < @filemtime($file)) return false; // cache older than files it depends on?
}
}
return true;
}
/**
* add dependencies to the depends array
*
* this method should only add dependencies,
* it should not remove any existing dependencies and
* it should only overwrite a dependency when the new value is more stringent than the old
*/
function _addDependencies() {
if (isset($_REQUEST['purge'])) $this->depends['purge'] = true; // purge requested
}
/**
* retrieve the cached data
*
* @param bool $clean true to clean line endings, false to leave line endings alone
* @return string cache contents
*/
function retrieveCache($clean=true) {
return io_readFile($this->cache, $clean);
}
/**
* cache $data
*
* @param string $data the data to be cached
* @return bool true on success, false otherwise
*/
function storeCache($data) {
return io_savefile($this->cache, $data);
}
/**
* remove any cached data associated with this cache instance
*/
function removeCache() {
@unlink($this->cache);
}
/**
* Record cache hits statistics.
* (Only when debugging allowed, to reduce overhead.)
*
* @param bool $success result of this cache use attempt
* @return bool pass-thru $success value
*/
function _stats($success) {
global $conf;
static $stats = NULL;
static $file;
if (!$conf['allowdebug']) { return $success; }
if (is_null($stats)) {
$file = $conf['cachedir'].'/cache_stats.txt';
$lines = explode("\n",io_readFile($file));
foreach ($lines as $line) {
$i = strpos($line,',');
$stats[substr($line,0,$i)] = $line;
}
}
if (isset($stats[$this->ext])) {
list($ext,$count,$hits) = explode(',',$stats[$this->ext]);
} else {
$ext = $this->ext;
$count = 0;
$hits = 0;
}
$count++;
if ($success) $hits++;
$stats[$this->ext] = "$ext,$count,$hits";
io_saveFile($file,join("\n",$stats));
return $success;
}
}
class cache_parser extends cache {
var $file = ''; // source file for cache
var $mode = ''; // input mode (represents the processing the input file will undergo)
var $_event = 'PARSER_CACHE_USE';
function cache_parser($id, $file, $mode) {
if ($id) $this->page = $id;
$this->file = $file;
$this->mode = $mode;
parent::cache($file.$_SERVER['HTTP_HOST'].$_SERVER['SERVER_PORT'],'.'.$mode);
}
function _useCache() {
if (!@file_exists($this->file)) return false; // source exists?
return parent::_useCache();
}
function _addDependencies() {
global $conf;
$this->depends['age'] = isset($this->depends['age']) ?
min($this->depends['age'],$conf['cachetime']) : $conf['cachetime'];
// parser cache file dependencies ...
$files = array($this->file, // ... source
DOKU_CONF.'dokuwiki.php', // ... config
DOKU_CONF.'local.php', // ... local config
DOKU_INC.'inc/parser/parser.php', // ... parser
DOKU_INC.'inc/parser/handler.php', // ... handler
);
$this->depends['files'] = !empty($this->depends['files']) ? array_merge($files, $this->depends['files']) : $files;
parent::_addDependencies();
}
}
class cache_renderer extends cache_parser {
function useCache($depends=array()) {
$use = parent::useCache($depends);
// meta data needs to be kept in step with the cache
if (!$use && isset($this->page)) {
p_set_metadata($this->page,array(),true);
}
return $use;
}
function _useCache() {
global $conf;
if (!parent::_useCache()) return false;
// for wiki pages, check metadata dependencies
if (isset($this->page)) {
$metadata = p_get_metadata($this->page);
// check currnent link existence is consistent with cache version
// first check the purgefile
// - if the cache is more recent that the purgefile we know no links can have been updated
if ($this->_time < @filemtime($conf['cachedir'].'/purgefile')) {
# $links = p_get_metadata($this->page,"relation references");
$links = $metadata['relation']['references'];
if (!empty($links)) {
foreach ($links as $id => $exists) {
if ($exists != page_exists($id,'',false)) return false;
}
}
}
}
return true;
}
function _addDependencies() {
// renderer cache file dependencies ...
$files = array(
DOKU_INC.'inc/parser/'.$this->mode.'.php', // ... the renderer
);
// page implies metadata and possibly some other dependencies
if (isset($this->page)) {
$metafile = metaFN($this->page,'.meta');
if (@file_exists($metafile)) {
$files[] = $metafile; // ... the page's own metadata
$files[] = DOKU_INC.'inc/parser/metadata.php'; // ... the metadata renderer
$valid = p_get_metadata($this->page, 'date valid');
if (!empty($valid['age'])) {
$this->depends['age'] = isset($this->depends['age']) ?
min($this->depends['age'],$valid['age']) : $valid['age'];
}
} else {
$this->depends['purge'] = true; // ... purging cache will generate metadata
return;
}
}
$this->depends['files'] = !empty($this->depends['files']) ? array_merge($files, $this->depends['files']) : $files;
parent::_addDependencies();
}
}
class cache_instructions extends cache_parser {
function cache_instructions($id, $file) {
parent::cache_parser($id, $file, 'i');
}
function retrieveCache() {
$contents = io_readFile($this->cache, false);
return !empty($contents) ? unserialize($contents) : array();
}
function storeCache($instructions) {
return io_savefile($this->cache,serialize($instructions));
}
}
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