File indexing completed on 2024-05-12 17:25:54

 <?php
 /////////////////////////////////////////////////////////////////
 /// getID3() by James Heinrich <info@getid3.org>               //
 //  available at http://getid3.sourceforge.net                 //
 //            or http://www.getid3.org                         //
 //          also https://github.com/JamesHeinrich/getID3       //
 /////////////////////////////////////////////////////////////////
 //                                                             //
 // extension.cache.dbm.php - part of getID3()                  //
 // Please see readme.txt for more information                  //
 //                                                            ///
 /////////////////////////////////////////////////////////////////
 //                                                             //
 // This extension written by Allan Hansen <ahØartemis*dk>      //
 //                                                            ///
 /////////////////////////////////////////////////////////////////
 
 
 /**
 * This is a caching extension for getID3(). It works the exact same
 * way as the getID3 class, but return cached information very fast
 *
 * Example:
 *
 *    Normal getID3 usage (example):
 *
 *       require_once 'getid3/getid3.php';
 *       $getID3 = new getID3;
 *       $getID3->encoding = 'UTF-8';
 *       $info1 = $getID3->analyze('file1.flac');
 *       $info2 = $getID3->analyze('file2.wv');
 *
 *    getID3_cached usage:
 *
 *       require_once 'getid3/getid3.php';
 *       require_once 'getid3/getid3/extension.cache.dbm.php';
 *       $getID3 = new getID3_cached('db3', '/tmp/getid3_cache.dbm',
 *                                          '/tmp/getid3_cache.lock');
 *       $getID3->encoding = 'UTF-8';
 *       $info1 = $getID3->analyze('file1.flac');
 *       $info2 = $getID3->analyze('file2.wv');
 *
 *
 * Supported Cache Types
 *
 *   SQL Databases:          (use extension.cache.mysql)
 *
 *   cache_type          cache_options
 *   -------------------------------------------------------------------
 *   mysql               host, database, username, password
 *
 *
 *   DBM-Style Databases:    (this extension)
 *
 *   cache_type          cache_options
 *   -------------------------------------------------------------------
 *   gdbm                dbm_filename, lock_filename
 *   ndbm                dbm_filename, lock_filename
 *   db2                 dbm_filename, lock_filename
 *   db3                 dbm_filename, lock_filename
 *   db4                 dbm_filename, lock_filename  (PHP5 required)
 *
 *   PHP must have write access to both dbm_filename and lock_filename.
 *
 *
 * Recommended Cache Types
 *
 *   Infrequent updates, many reads      any DBM
 *   Frequent updates                    mysql
 */
 
 
 class getID3_cached_dbm extends getID3
 {
 
   // public: constructor - see top of this file for cache type and cache_options
   public function getID3_cached_dbm($cache_type, $dbm_filename, $lock_filename) {
 
     // Check for dba extension
     if (!extension_loaded('dba')) {
       throw new Exception('PHP is not compiled with dba support, required to use DBM style cache.');
     }
 
     // Check for specific dba driver
     if (!function_exists('dba_handlers') || !in_array($cache_type, dba_handlers())) {
       throw new Exception('PHP is not compiled --with '.$cache_type.' support, required to use DBM style cache.');
     }
 
     // Create lock file if needed
     if (!file_exists($lock_filename)) {
       if (!touch($lock_filename)) {
         throw new Exception('failed to create lock file: '.$lock_filename);
       }
     }
 
     // Open lock file for writing
     if (!is_writeable($lock_filename)) {
       throw new Exception('lock file: '.$lock_filename.' is not writable');
     }
     $this->lock = fopen($lock_filename, 'w');
 
     // Acquire exclusive write lock to lock file
     flock($this->lock, LOCK_EX);
 
     // Create dbm-file if needed
     if (!file_exists($dbm_filename)) {
       if (!touch($dbm_filename)) {
         throw new Exception('failed to create dbm file: '.$dbm_filename);
       }
     }
 
     // Try to open dbm file for writing
     $this->dba = dba_open($dbm_filename, 'w', $cache_type);
     if (!$this->dba) {
 
       // Failed - create new dbm file
       $this->dba = dba_open($dbm_filename, 'n', $cache_type);
 
       if (!$this->dba) {
         throw new Exception('failed to create dbm file: '.$dbm_filename);
       }
 
       // Insert getID3 version number
       dba_insert(getID3::VERSION, getID3::VERSION, $this->dba);
     }
 
     // Init misc values
     $this->cache_type   = $cache_type;
     $this->dbm_filename = $dbm_filename;
 
     // Register destructor
     register_shutdown_function(array($this, '__destruct'));
 
     // Check version number and clear cache if changed
     if (dba_fetch(getID3::VERSION, $this->dba) != getID3::VERSION) {
       $this->clear_cache();
     }
 
     parent::__construct();
   }
 
 
 
   // public: destructor
   public function __destruct() {
 
     // Close dbm file
     dba_close($this->dba);
 
     // Release exclusive lock
     flock($this->lock, LOCK_UN);
 
     // Close lock file
     fclose($this->lock);
   }
 
 
 
   // public: clear cache
   public function clear_cache() {
 
     // Close dbm file
     dba_close($this->dba);
 
     // Create new dbm file
     $this->dba = dba_open($this->dbm_filename, 'n', $this->cache_type);
 
     if (!$this->dba) {
       throw new Exception('failed to clear cache/recreate dbm file: '.$this->dbm_filename);
     }
 
     // Insert getID3 version number
     dba_insert(getID3::VERSION, getID3::VERSION, $this->dba);
 
     // Re-register shutdown function
     register_shutdown_function(array($this, '__destruct'));
   }
 
 
 
   // public: analyze file
   public function analyze($filename) {
 
     if (file_exists($filename)) {
 
       // Calc key     filename::mod_time::size    - should be unique
       $key = $filename.'::'.filemtime($filename).'::'.filesize($filename);
 
       // Loopup key
       $result = dba_fetch($key, $this->dba);
 
       // Hit
       if ($result !== false) {
         return unserialize($result);
       }
     }
 
     // Miss
     $result = parent::analyze($filename);
 
     // Save result
     if (file_exists($filename)) {
       dba_insert($key, serialize($result), $this->dba);
     }
 
     return $result;
   }
 
 }