1 files changed, 292 insertions, 0 deletions
diff --git a/lib/dokuwiki/inc/cache.php b/lib/dokuwiki/inc/cache.php
new file mode 100644
index 000000000..8e8adfd6d
--- /dev/null
+++ b/lib/dokuwiki/inc/cache.php
@@ -0,0 +1,292 @@
+<?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')) die('meh.');
+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, $config_cascade;
+
+    $this->depends['age'] = isset($this->depends['age']) ?
+                   min($this->depends['age'],$conf['cachetime']) : $conf['cachetime'];
+
+    // parser cache file dependencies ...
+    $files = array($this->file,                                     // ... source
+                   DOKU_INC.'inc/parser/parser.php',                // ... parser
+                   DOKU_INC.'inc/parser/handler.php',               // ... handler
+             );
+    $files = array_merge($files, getConfigFiles('main'));           // ... wiki settings
+
+    $this->depends['files'] = !empty($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 $conf;
+
+    if (!parent::_useCache()) return false;
+
+    if (!isset($this->page)) {
+      return true;
+    }
+
+    // check current link existence is consistent with cache version
+    // first check the purgefile
+    // - if the cache is more recent than the purgefile we know no links can have been updated
+    if ($this->_time >= @filemtime($conf['cachedir'].'/purgefile')) {
+      return true;
+    }
+
+    // for wiki pages, check metadata dependencies
+    $metadata = p_get_metadata($this->page);
+
+    if (!isset($metadata['relation']['references']) ||
+         empty($metadata['relation']['references'])) {
+      return true;
+    }
+
+    foreach ($metadata['relation']['references'] 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, $file, 'i');
+  }
+
+  function retrieveCache($clean=true) {
+    $contents = io_readFile($this->cache, false);
+    return !empty($contents) ? unserialize($contents) : array();
+  }
+
+  function storeCache($instructions) {
+    return io_savefile($this->cache,serialize($instructions));
+  }
+}