includes/ObjectCache.php

   1 <?php
   2 # Copyright (C) 2003-2004 Brion Vibber <brion@pobox.com>
   3 # http://www.mediawiki.org/
   4 #
   5 # This program is free software; you can redistribute it and/or modify
   6 # it under the terms of the GNU General Public License as published by
   7 # the Free Software Foundation; either version 2 of the License, or
   8 # (at your option) any later version.
   9 #
  10 # This program is distributed in the hope that it will be useful,
  11 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13 # GNU General Public License for more details.
  14 #
  15 # You should have received a copy of the GNU General Public License along
  16 # with this program; if not, write to the Free Software Foundation, Inc.,
  17 # 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  18 # http://www.gnu.org/copyleft/gpl.html
  19
  20 # Simple generic object store
  21 # interface is intended to be more or less compatible with
  22 # the PHP memcached client.
  23 #
  24 # backends for local hash array and SQL table included:
  25 #  $bag = new HashBagOStuff();
  26 #  $bag = new MysqlBagOStuff($tablename); # connect to db first
  27
  28 class /* abstract */ BagOStuff {
  29         var $debugmode;
  30
  31         function BagOStuff() {
  32                 set_debug( false );
  33         }
  34
  35         function set_debug($bool) {
  36                 $this->debugmode = $bool;
  37         }
  38
  39         /* *** THE GUTS OF THE OPERATION *** */
  40         /* Override these with functional things in subclasses */
  41
  42         function get($key) {
  43                 /* stub */
  44                 return false;
  45         }
  46
  47         function set($key, $value, $exptime=0) {
  48                 /* stub */
  49                 return false;
  50         }
  51
  52         function delete($key, $time=0) {
  53                 /* stub */
  54                 return false;
  55         }
  56
  57         /* *** Emulated functions *** */
  58         /* Better performance can likely be got with custom written versions */
  59         function get_multi($keys) {
  60                 $out = array();
  61                 foreach($keys as $key)
  62                         $out[$key] = $this->get($key);
  63                 return $out;
  64         }
  65
  66         function set_multi($hash, $exptime=0) {
  67                 foreach($hash as $key => $value)
  68                         $this->set($key, $value, $exptime);
  69         }
  70
  71         function add($key, $value, $exptime=0) {
  72                 if( $this->get($key) === false )
  73                         $this->set($key, $value, $exptime);
  74         }
  75
  76         function add_multi($hash, $exptime=0) {
  77                 foreach($hash as $key => $value)
  78                         $this->add($key, $value, $exptime);
  79         }
  80
  81         function delete_multi($keys, $time=0) {
  82                 foreach($keys as $key)
  83                         $this->delete($key, $time);
  84         }
  85
  86         function replace($key, $value, $exptime=0) {
  87                 if( $this->get($key) !== false )
  88                         $this->set($key, $value, $exptime);
  89         }
  90
  91         function incr($key, $value=1) {
  92                 $value = intval($value);
  93                 if($value < 0) $value = 0;
  94                 if( ($n = $this->get($key)) !== false ) {
  95                         $this->set($key, $n+$value); // exptime?
  96                         return $n+$value;
  97                 } else {
  98                         return false;
  99                 }
 100         }
 101
 102         function decr($key, $value=1) {
 103                 $value = intval($value);
 104                 if($value < 0) $value = 0;
 105                 if( ($n = $this->get($key)) !== false ) {
 106                         $m = $n - $value;
 107                         if($m < 0) $m = 0;
 108                         $this->set($key, $m); // exptime?
 109                         return $m;
 110                 } else {
 111                         return false;
 112                 }
 113         }
 114
 115         function _debug($text) {
 116                 if($this->debugmode)
 117                         echo "\ndebug: $text\n";
 118         }
 119 }
 120
 121
 122 /* Functional versions! */
 123 class HashBagOStuff extends BagOStuff {
 124         /*
 125            This is a test of the interface, mainly. It stores
 126            things in an associative array, which is not going to
 127            persist between program runs.
 128         */
 129         var $bag;
 130
 131         function HashBagOStuff() {
 132                 $this->bag = array();
 133         }
 134
 135         function _expire($key) {
 136                 $et = $this->bag[$key][1];
 137                 if(($et == 0) || ($et > time()))
 138                         return false;
 139                 $this->delete($key);
 140                 return true;
 141         }
 142
 143         function get($key) {
 144                 if(!$this->bag[$key])
 145                         return false;
 146                 if($this->_expire($key))
 147                         return false;
 148                 return $this->bag[$key][0];
 149         }
 150
 151         function set($key,$value,$exptime=0) {
 152                 if(($exptime != 0) && ($exptime < 3600*24*30))
 153                         $exptime = time() + $exptime;
 154                 $this->bag[$key] = array( $value, $exptime );
 155         }
 156
 157         function delete($key,$time=0) {
 158                 if(!$this->bag[$key])
 159                         return false;
 160                 unset($this->bag[$key]);
 161                 return true;
 162         }
 163 }
 164
 165 /*
 166 CREATE TABLE objectcache (
 167   keyname char(255) binary not null default '',
 168   value mediumblob,
 169   exptime datetime,
 170   unique key (keyname),
 171   key (exptime)
 172 );
 173 */
 174 class /* abstract */ SqlBagOStuff extends BagOStuff {
 175         var $table;
 176         function SqlBagOStuff($tablename = "objectcache") {
 177                 $this->table = $tablename;
 178         }
 179
 180         function get($key) {
 181                 /* expire old entries if any */
 182                 $this->expireall();
 183
 184                 $res = $this->_query(
 185                         "SELECT value,exptime FROM $0 WHERE keyname='$1'", $key);
 186                 if(!$res) {
 187                         $this->_debug("get: ** error: " . $this->_dberror($res) . " **");
 188                         return false;
 189                 }
 190                 if($arr = $this->_fetchrow($res)) {
 191                         $this->_debug("get: retrieved data; exp time is " . $arr['exptime']);
 192                         return unserialize($arr['value']);
 193                 } else {
 194                         $this->_debug("get: no matching rows");
 195                 }
 196                 return false;
 197         }
 198
 199         function set($key,$value,$exptime=0) {
 200                 $exptime = intval($exptime);
 201                 if($exptime < 0) $exptime = 0;
 202                 if($exptime == 0) {
 203                         $exp = $this->_maxdatetime();
 204                 } else {
 205                         if($exptime < 3600*24*30)
 206                                 $exptime += time();
 207                         $exp = $this->_fromunixtime($exptime);
 208                 }
 209                 $this->delete( $key );
 210                 $this->_query(
 211                         "INSERT INTO $0 (keyname,value,exptime) VALUES('$1','$2',$exp)",
 212                         $key, serialize(&$value));
 213                 return true; /* ? */
 214         }
 215
 216         function delete($key,$time=0) {
 217                 $this->_query(
 218                         "DELETE FROM $0 WHERE keyname='$1'", $key );
 219                 return true; /* ? */
 220         }
 221
 222         function _query($sql) {
 223                 $reps = func_get_args();
 224                 $reps[0] = $this->table;
 225                 // ewwww
 226                 for($i=0;$i<count($reps);$i++) {
 227                         $sql = str_replace(
 228                                 "$" . $i,
 229                                 $this->_strencode($reps[$i]),
 230                                 $sql);
 231                 }
 232                 $res = $this->_doquery($sql);
 233                 if($res === false) {
 234                         $this->_debug("query failed: " . $this->_dberror($res));
 235                 }
 236                 return $res;
 237         }
 238
 239         function _strencode($str) {
 240                 /* Protect strings in SQL */
 241                 return str_replace( "'", "''", $str );
 242         }
 243
 244         function _doquery($sql) {
 245                 die( "abstract function SqlBagOStuff::_doquery() must be defined" );
 246         }
 247
 248         function _fetchrow($res) {
 249                 die( "abstract function SqlBagOStuff::_fetchrow() must be defined" );
 250         }
 251
 252         function _freeresult($result) {
 253                 /* stub */
 254                 return false;
 255         }
 256
 257         function _dberror($result) {
 258                 /* stub */
 259                 return "unknown error";
 260         }
 261
 262         function _maxdatetime() {
 263                 die( "abstract function SqlBagOStuff::_maxdatetime() must be defined" );
 264         }
 265
 266         function _fromunixtime() {
 267                 die( "abstract function SqlBagOStuff::_fromunixtime() must be defined" );
 268         }
 269
 270         function expireall() {
 271                 /* Remove any items that have expired */
 272                 $this->_query( "DELETE FROM $0 WHERE exptime<=NOW()" );
 273         }
 274
 275         function deleteall() {
 276                 /* Clear *all* items from cache table */
 277                 $this->_query( "DELETE FROM $0" );
 278         }
 279 }
 280
 281 class MysqlBagOStuff extends SqlBagOStuff {
 282         function _doquery($sql) {
 283                 return mysql_query($sql);
 284         }
 285         function _fetchrow($result) {
 286                 return mysql_fetch_array($result);
 287         }
 288         function _freeresult($result) {
 289                 return mysql_free_result($result);
 290         }
 291         function _dberror($result) {
 292                 if($result)
 293                         return mysql_error($result);
 294                 else
 295                         return mysql_error();
 296         }
 297
 298         function _maxdatetime() {
 299                 return "'9999-12-31 12:59:59'";
 300         }
 301
 302         function _fromunixtime($ts) {
 303                 return "FROM_UNIXTIME($ts)";
 304         }
 305
 306         function _strencode($s) {
 307                 return mysql_escape_string($s);
 308         }
 309 }
 310
 311 class MediaWikiBagOStuff extends MysqlBagOStuff {
 312         function _doquery($sql) {
 313                 return wfQuery($sql, DB_READ, "MediaWikiBagOStuff:_doquery");
 314         }
 315         function _freeresult($result) {
 316                 return wfFreeResult($result);
 317         }
 318 }
 319
 320 ?>