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| -rw-r--r-- | plugins/dokuwiki/inc/cache.php | 291 |
diff --git a/plugins/dokuwiki/inc/cache.php b/plugins/dokuwiki/inc/cache.php new file mode 100644 index 0000000..4de19be --- /dev/null +++ b/plugins/dokuwiki/inc/cache.php @@ -0,0 +1,291 @@ +<?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',realpath(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 $_event = ''; // event to be triggered during useCache + + function __construct($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 $data the data to be cached + * @return none + */ + function storeCache($data) { + 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 $_event = 'PARSER_CACHE_USE'; + + function __construct($id, $file, $mode) { + if ($id) $this->page = $id; + $this->file = $file; + $this->mode = $mode; + + parent::__construct($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 != @file_exists(wikiFN($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']) : $files; + parent::_addDependencies(); + } +} + +class cache_instructions extends cache_parser { + + function __construct($id, $file) { + parent::__construct($id, $file, 'i'); + } + + function retrieveCache($clean=true) { + $contents = io_readFile($this->cache, false); + return !empty($contents) ? unserialize($contents) : array(); + } + + function storeCache($instructions) { + io_savefile($this->cache,serialize($instructions)); + } +} |