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, $exptime);
  76                         return true;
  77                 }
  78         }
  79
  80         function add_multi($hash, $exptime=0) {
  81                 foreach($hash as $key => $value)
  82                         $this->add($key, $value, $exptime);
  83         }
  84
  85         function delete_multi($keys, $time=0) {
  86                 foreach($keys as $key)
  87                         $this->delete($key, $time);
  88         }
  89
  90         function replace($key, $value, $exptime=0) {
  91                 if( $this->get($key) !== false )
  92                         $this->set($key, $value, $exptime);
  93         }
  94
  95         function incr($key, $value=1) {
  96                 $value = intval($value);
  97                 if($value < 0) $value = 0;
  98                 if( ($n = $this->get($key)) !== false ) {
  99                         $this->set($key, $n+$value); // exptime?
 100                         return $n+$value;
 101                 } else {
 102                         return false;
 103                 }
 104         }
 105
 106         function decr($key, $value=1) {
 107                 $value = intval($value);
 108                 if($value < 0) $value = 0;
 109                 if( ($n = $this->get($key)) !== false ) {
 110                         $m = $n - $value;
 111                         if($m < 0) $m = 0;
 112                         $this->set($key, $m); // exptime?
 113                         return $m;
 114                 } else {
 115                         return false;
 116                 }
 117         }
 118
 119         function _debug($text) {
 120                 if($this->debugmode)
 121                         wfDebug("BagOStuff debug: $text\n");
 122         }
 123 }
 124
 125
 126 /* Functional versions! */
 127 class HashBagOStuff extends BagOStuff {
 128         /*
 129            This is a test of the interface, mainly. It stores
 130            things in an associative array, which is not going to
 131            persist between program runs.
 132         */
 133         var $bag;
 134
 135         function HashBagOStuff() {
 136                 $this->bag = array();
 137         }
 138
 139         function _expire($key) {
 140                 $et = $this->bag[$key][1];
 141                 if(($et == 0) || ($et > time()))
 142                         return false;
 143                 $this->delete($key);
 144                 return true;
 145         }
 146
 147         function get($key) {
 148                 if(!$this->bag[$key])
 149                         return false;
 150                 if($this->_expire($key))
 151                         return false;
 152                 return $this->bag[$key][0];
 153         }
 154
 155         function set($key,$value,$exptime=0) {
 156                 if(($exptime != 0) && ($exptime < 3600*24*30))
 157                         $exptime = time() + $exptime;
 158                 $this->bag[$key] = array( $value, $exptime );
 159         }
 160
 161         function delete($key,$time=0) {
 162                 if(!$this->bag[$key])
 163                         return false;
 164                 unset($this->bag[$key]);
 165                 return true;
 166         }
 167 }
 168
 169 /*
 170 CREATE TABLE objectcache (
 171   keyname char(255) binary not null default '',
 172   value mediumblob,
 173   exptime datetime,
 174   unique key (keyname),
 175   key (exptime)
 176 );
 177 */
 178 class /* abstract */ SqlBagOStuff extends BagOStuff {
 179         var $table;
 180         function SqlBagOStuff($tablename = "objectcache") {
 181                 $this->table = $tablename;
 182         }
 183
 184         function get($key) {
 185                 /* expire old entries if any */
 186                 $this->expireall();
 187
 188                 $res = $this->_query(
 189                         "SELECT value,exptime FROM $0 WHERE keyname='$1'", $key);
 190                 if(!$res) {
 191                         $this->_debug("get: ** error: " . $this->_dberror($res) . " **");
 192                         return false;
 193                 }
 194                 if($row=$this->_fetchobject($res)) {
 195                         $this->_debug("get: retrieved data; exp time is " . $row->exptime);
 196                         return unserialize($row->value);
 197                 } else {
 198                         $this->_debug("get: no matching rows");
 199                 }
 200                 return false;
 201         }
 202
 203         function set($key,$value,$exptime=0) {
 204                 $exptime = intval($exptime);
 205                 if($exptime < 0) $exptime = 0;
 206                 if($exptime == 0) {
 207                         $exp = $this->_maxdatetime();
 208                 } else {
 209                         if($exptime < 3600*24*30)
 210                                 $exptime += time();
 211                         $exp = $this->_fromunixtime($exptime);
 212                 }
 213                 $this->delete( $key );
 214                 $this->_query(
 215                         "INSERT INTO $0 (keyname,value,exptime) VALUES('$1','$2','$exp')",
 216                         $key, serialize(&$value));
 217                 return true; /* ? */
 218         }
 219
 220         function delete($key,$time=0) {
 221                 $this->_query(
 222                         "DELETE FROM $0 WHERE keyname='$1'", $key );
 223                 return true; /* ? */
 224         }
 225
 226         function _query($sql) {
 227                 $reps = func_get_args();
 228                 $reps[0] = $this->table;
 229                 // ewwww
 230                 for($i=0;$i<count($reps);$i++) {
 231                         $sql = str_replace(
 232                                 "$" . $i,
 233                                 $this->_strencode($reps[$i]),
 234                                 $sql);
 235                 }
 236                 $res = $this->_doquery($sql);
 237                 if($res == false) {
 238                         $this->_debug("query failed: " . $this->_dberror($res));
 239                 }
 240                 return $res;
 241         }
 242
 243         function _strencode($str) {
 244                 /* Protect strings in SQL */
 245                 return str_replace( "'", "''", $str );
 246         }
 247
 248         function _doquery($sql) {
 249                 die( "abstract function SqlBagOStuff::_doquery() must be defined" );
 250         }
 251
 252         function _fetchrow($res) {
 253                 die( "abstract function SqlBagOStuff::_fetchrow() must be defined" );
 254         }
 255
 256         function _freeresult($result) {
 257                 /* stub */
 258                 return false;
 259         }
 260
 261         function _dberror($result) {
 262                 /* stub */
 263                 return "unknown error";
 264         }
 265
 266         function _maxdatetime() {
 267                 die( "abstract function SqlBagOStuff::_maxdatetime() must be defined" );
 268         }
 269
 270         function _fromunixtime() {
 271                 die( "abstract function SqlBagOStuff::_fromunixtime() must be defined" );
 272         }
 273
 274         function expireall() {
 275                 /* Remove any items that have expired */
 276                 $now=$this->_fromunixtime(time());
 277                 $this->_query( "DELETE FROM $0 WHERE exptime<'$now'" );
 278         }
 279
 280         function deleteall() {
 281                 /* Clear *all* items from cache table */
 282                 $this->_query( "DELETE FROM $0" );
 283         }
 284 }
 285
 286 class MediaWikiBagOStuff extends SqlBagOStuff {
 287         function _doquery($sql) {
 288                 return wfQuery($sql, DB_READ, "MediaWikiBagOStuff:_doquery");
 289         }
 290         function _fetchobject($result) {
 291                 return wfFetchObject($result);
 292         }
 293         function _freeresult($result) {
 294                 return wfFreeResult($result);
 295         }
 296         function _dberror($result) {
 297                 return wfLastError();
 298         }
 299         function _maxdatetime() {
 300                 return "9999-12-31 12:59:59";
 301         }
 302         function _fromunixtime($ts) {
 303                 return gmdate( "Y-m-d H:i:s", $ts );
 304         }
 305         function _strencode($s) {
 306                 return wfStrEncode($s);
 307         }
 308 }
 309
 310 ?>