includes/ObjectCache.php

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