diff options
Diffstat (limited to 'platform/www/inc/Cache/Cache.php')
| -rw-r--r-- | platform/www/inc/Cache/Cache.php | 240 |
1 files changed, 240 insertions, 0 deletions
diff --git a/platform/www/inc/Cache/Cache.php b/platform/www/inc/Cache/Cache.php new file mode 100644 index 0000000..af82e6b --- /dev/null +++ b/platform/www/inc/Cache/Cache.php @@ -0,0 +1,240 @@ +<?php + +namespace dokuwiki\Cache; + +use dokuwiki\Debug\PropertyDeprecationHelper; +use dokuwiki\Extension\Event; + +/** + * Generic handling of caching + */ +class Cache +{ + use PropertyDeprecationHelper; + + public $key = ''; // primary identifier for this item + public $ext = ''; // file ext for cache data, secondary identifier for this item + public $cache = ''; // cache file name + public $depends = array(); // array containing cache dependency information, + // used by makeDefaultCacheDecision to determine cache validity + + // phpcs:disable + /** + * @deprecated since 2019-02-02 use the respective getters instead! + */ + protected $_event = ''; // event to be triggered during useCache + protected $_time; + protected $_nocache = false; // if set to true, cache will not be used or stored + // phpcs:enable + + /** + * @param string $key primary identifier + * @param string $ext file extension + */ + public function __construct($key, $ext) + { + $this->key = $key; + $this->ext = $ext; + $this->cache = getCacheName($key, $ext); + + /** + * @deprecated since 2019-02-02 use the respective getters instead! + */ + $this->deprecatePublicProperty('_event'); + $this->deprecatePublicProperty('_time'); + $this->deprecatePublicProperty('_nocache'); + } + + public function getTime() + { + return $this->_time; + } + + public function getEvent() + { + return $this->_event; + } + + public function setEvent($event) + { + $this->_event = $event; + } + + /** + * public method to determine whether the cache can be used + * + * to assist in centralisation of event triggering and calculation of cache statistics, + * don't override this function override makeDefaultCacheDecision() + * + * @param array $depends array of cache dependencies, support dependecies: + * 'age' => max age of the cache in seconds + * 'files' => cache must be younger than mtime of each file + * (nb. dependency passes if file doesn't exist) + * + * @return bool true if cache can be used, false otherwise + */ + public function useCache($depends = array()) + { + $this->depends = $depends; + $this->addDependencies(); + + if ($this->getEvent()) { + return $this->stats( + Event::createAndTrigger( + $this->getEvent(), + $this, + array($this, 'makeDefaultCacheDecision') + ) + ); + } + + return $this->stats($this->makeDefaultCacheDecision()); + } + + /** + * internal 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 + * + * Note that this function needs to be public as it is used as callback for the event handler + * + * can be overridden + * + * @internal This method may only be called by the event handler! Call \dokuwiki\Cache\Cache::useCache instead! + * + * @return bool see useCache() + */ + public function makeDefaultCacheDecision() + { + if ($this->_nocache) { + return false; + } // caching turned off + if (!empty($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 + */ + protected function addDependencies() + { + global $INPUT; + if ($INPUT->has('purge')) { + $this->depends['purge'] = true; + } // purge requested + } + + /** + * retrieve the cached data + * + * @param bool $clean true to clean line endings, false to leave line endings alone + * @return string cache contents + */ + public function retrieveCache($clean = true) + { + return io_readFile($this->cache, $clean); + } + + /** + * cache $data + * + * @param string $data the data to be cached + * @return bool true on success, false otherwise + */ + public function storeCache($data) + { + if ($this->_nocache) { + return false; + } + + return io_saveFile($this->cache, $data); + } + + /** + * remove any cached data associated with this cache instance + */ + public function removeCache() + { + @unlink($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 $success value + */ + protected function stats($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; + } + + /** + * @return bool + */ + public function isNoCache() + { + return $this->_nocache; + } +} |