www/plugins-dist/medias/lib/getid3/extension.cache.dbm.php

   1 <?php
   2
   3 /////////////////////////////////////////////////////////////////
   4 /// getID3() by James Heinrich <info@getid3.org>               //
   5 //  available at https://github.com/JamesHeinrich/getID3       //
   6 //            or https://www.getid3.org                        //
   7 //            or http://getid3.sourceforge.net                 //
   8 //                                                             //
   9 // extension.cache.dbm.php - part of getID3()                  //
  10 // Please see readme.txt for more information                  //
  11 //                                                            ///
  12 /////////////////////////////////////////////////////////////////
  13 //                                                             //
  14 // This extension written by Allan Hansen <ahØartemis*dk>      //
  15 //                                                            ///
  16 /////////////////////////////////////////////////////////////////
  17
  18
  19 /**
  20 * This is a caching extension for getID3(). It works the exact same
  21 * way as the getID3 class, but return cached information very fast
  22 *
  23 * Example:
  24 *
  25 *    Normal getID3 usage (example):
  26 *
  27 *       require_once 'getid3/getid3.php';
  28 *       $getID3 = new getID3;
  29 *       $getID3->encoding = 'UTF-8';
  30 *       $info1 = $getID3->analyze('file1.flac');
  31 *       $info2 = $getID3->analyze('file2.wv');
  32 *
  33 *    getID3_cached usage:
  34 *
  35 *       require_once 'getid3/getid3.php';
  36 *       require_once 'getid3/getid3/extension.cache.dbm.php';
  37 *       $getID3 = new getID3_cached('db3', '/tmp/getid3_cache.dbm',
  38 *                                          '/tmp/getid3_cache.lock');
  39 *       $getID3->encoding = 'UTF-8';
  40 *       $info1 = $getID3->analyze('file1.flac');
  41 *       $info2 = $getID3->analyze('file2.wv');
  42 *
  43 *
  44 * Supported Cache Types
  45 *
  46 *   SQL Databases:          (use extension.cache.mysql)
  47 *
  48 *   cache_type          cache_options
  49 *   -------------------------------------------------------------------
  50 *   mysql               host, database, username, password
  51 *
  52 *
  53 *   DBM-Style Databases:    (this extension)
  54 *
  55 *   cache_type          cache_options
  56 *   -------------------------------------------------------------------
  57 *   gdbm                dbm_filename, lock_filename
  58 *   ndbm                dbm_filename, lock_filename
  59 *   db2                 dbm_filename, lock_filename
  60 *   db3                 dbm_filename, lock_filename
  61 *   db4                 dbm_filename, lock_filename  (PHP5 required)
  62 *
  63 *   PHP must have write access to both dbm_filename and lock_filename.
  64 *
  65 *
  66 * Recommended Cache Types
  67 *
  68 *   Infrequent updates, many reads      any DBM
  69 *   Frequent updates                    mysql
  70 */
  71
  72
  73 class getID3_cached_dbm extends getID3
  74 {
  75         /**
  76          * @var resource
  77          */
  78         private $dba;
  79
  80         /**
  81          * @var resource|bool
  82          */
  83         private $lock;
  84
  85         /**
  86          * @var string
  87          */
  88         private $cache_type;
  89
  90         /**
  91          * @var string
  92          */
  93         private $dbm_filename;
  94
  95         /**
  96          * constructor - see top of this file for cache type and cache_options
  97          *
  98          * @param string $cache_type
  99          * @param string $dbm_filename
 100          * @param string $lock_filename
 101          *
 102          * @throws Exception
 103          * @throws getid3_exception
 104          */
 105         public function __construct($cache_type, $dbm_filename, $lock_filename) {
 106
 107                 // Check for dba extension
 108                 if (!extension_loaded('dba')) {
 109                         throw new Exception('PHP is not compiled with dba support, required to use DBM style cache.');
 110                 }
 111
 112                 // Check for specific dba driver
 113                 if (!function_exists('dba_handlers') || !in_array($cache_type, dba_handlers())) {
 114                         throw new Exception('PHP is not compiled --with '.$cache_type.' support, required to use DBM style cache.');
 115                 }
 116
 117                 // Create lock file if needed
 118                 if (!file_exists($lock_filename)) {
 119                         if (!touch($lock_filename)) {
 120                                 throw new Exception('failed to create lock file: '.$lock_filename);
 121                         }
 122                 }
 123
 124                 // Open lock file for writing
 125                 if (!is_writeable($lock_filename)) {
 126                         throw new Exception('lock file: '.$lock_filename.' is not writable');
 127                 }
 128                 $this->lock = fopen($lock_filename, 'w');
 129
 130                 // Acquire exclusive write lock to lock file
 131                 flock($this->lock, LOCK_EX);
 132
 133                 // Create dbm-file if needed
 134                 if (!file_exists($dbm_filename)) {
 135                         if (!touch($dbm_filename)) {
 136                                 throw new Exception('failed to create dbm file: '.$dbm_filename);
 137                         }
 138                 }
 139
 140                 // Try to open dbm file for writing
 141                 $this->dba = dba_open($dbm_filename, 'w', $cache_type);
 142                 if (!$this->dba) {
 143
 144                         // Failed - create new dbm file
 145                         $this->dba = dba_open($dbm_filename, 'n', $cache_type);
 146
 147                         if (!$this->dba) {
 148                                 throw new Exception('failed to create dbm file: '.$dbm_filename);
 149                         }
 150
 151                         // Insert getID3 version number
 152                         dba_insert(getID3::VERSION, getID3::VERSION, $this->dba);
 153                 }
 154
 155                 // Init misc values
 156                 $this->cache_type   = $cache_type;
 157                 $this->dbm_filename = $dbm_filename;
 158
 159                 // Register destructor
 160                 register_shutdown_function(array($this, '__destruct'));
 161
 162                 // Check version number and clear cache if changed
 163                 if (dba_fetch(getID3::VERSION, $this->dba) != getID3::VERSION) {
 164                         $this->clear_cache();
 165                 }
 166
 167                 parent::__construct();
 168         }
 169
 170
 171
 172         /**
 173          * destructor
 174          */
 175         public function __destruct() {
 176
 177                 // Close dbm file
 178                 dba_close($this->dba);
 179
 180                 // Release exclusive lock
 181                 flock($this->lock, LOCK_UN);
 182
 183                 // Close lock file
 184                 fclose($this->lock);
 185         }
 186
 187
 188
 189         /**
 190          * clear cache
 191          *
 192          * @throws Exception
 193          */
 194         public function clear_cache() {
 195
 196                 // Close dbm file
 197                 dba_close($this->dba);
 198
 199                 // Create new dbm file
 200                 $this->dba = dba_open($this->dbm_filename, 'n', $this->cache_type);
 201
 202                 if (!$this->dba) {
 203                         throw new Exception('failed to clear cache/recreate dbm file: '.$this->dbm_filename);
 204                 }
 205
 206                 // Insert getID3 version number
 207                 dba_insert(getID3::VERSION, getID3::VERSION, $this->dba);
 208
 209                 // Re-register shutdown function
 210                 register_shutdown_function(array($this, '__destruct'));
 211         }
 212
 213
 214
 215         /**
 216          * clear cache
 217          *
 218          * @param string   $filename
 219          * @param int      $filesize
 220          * @param string   $original_filename
 221          * @param resource $fp
 222          *
 223          * @return mixed
 224          */
 225         public function analyze($filename, $filesize=null, $original_filename='', $fp=null) {
 226
 227                 if (file_exists($filename)) {
 228
 229                         // Calc key     filename::mod_time::size    - should be unique
 230                         $key = $filename.'::'.filemtime($filename).'::'.filesize($filename);
 231
 232                         // Loopup key
 233                         $result = dba_fetch($key, $this->dba);
 234
 235                         // Hit
 236                         if ($result !== false) {
 237                                 return unserialize($result);
 238                         }
 239                 }
 240
 241                 // Miss
 242                 $result = parent::analyze($filename, $filesize, $original_filename, $fp);
 243
 244                 // Save result
 245                 if (isset($key) && file_exists($filename)) {
 246                         dba_insert($key, serialize($result), $this->dba);
 247                 }
 248
 249                 return $result;
 250         }
 251
 252 }