includes/BagOStuff.php

   1 <?php
   2 #
   3 # Copyright (C) 2003-2004 Brion Vibber <brion@pobox.com>
   4 # http://www.mediawiki.org/
   5 #
   6 # This program is free software; you can redistribute it and/or modify
   7 # it under the terms of the GNU General Public License as published by
   8 # the Free Software Foundation; either version 2 of the License, or
   9 # (at your option) any later version.
  10 #
  11 # This program is distributed in the hope that it will be useful,
  12 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  14 # GNU General Public License for more details.
  15 #
  16 # You should have received a copy of the GNU General Public License along
  17 # with this program; if not, write to the Free Software Foundation, Inc.,
  18 # 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  19 # http://www.gnu.org/copyleft/gpl.html
  20 /**
  21  *
  22  * @package MediaWiki
  23  */
  24
  25 /**
  26  * Simple generic object store
  27  *
  28  * interface is intended to be more or less compatible with
  29  * the PHP memcached client.
  30  *
  31  * backends for local hash array and SQL table included:
  32  * $bag = new HashBagOStuff();
  33  * $bag = new MysqlBagOStuff($tablename); # connect to db first
  34  *
  35  * @package MediaWiki
  36  */
  37 class BagOStuff {
  38         var $debugmode;
  39
  40         function BagOStuff() {
  41                 $this->set_debug( false );
  42         }
  43
  44         function set_debug($bool) {
  45                 $this->debugmode = $bool;
  46         }
  47
  48         /* *** THE GUTS OF THE OPERATION *** */
  49         /* Override these with functional things in subclasses */
  50
  51         function get($key) {
  52                 /* stub */
  53                 return false;
  54         }
  55
  56         function set($key, $value, $exptime=0) {
  57                 /* stub */
  58                 return false;
  59         }
  60
  61         function delete($key, $time=0) {
  62                 /* stub */
  63                 return false;
  64         }
  65
  66         function lock($key, $timeout = 0) {
  67                 /* stub */
  68                 return true;
  69         }
  70
  71         function unlock($key) {
  72                 /* stub */
  73                 return true;
  74         }
  75
  76         /* *** Emulated functions *** */
  77         /* Better performance can likely be got with custom written versions */
  78         function get_multi($keys) {
  79                 $out = array();
  80                 foreach($keys as $key)
  81                         $out[$key] = $this->get($key);
  82                 return $out;
  83         }
  84
  85         function set_multi($hash, $exptime=0) {
  86                 foreach($hash as $key => $value)
  87                         $this->set($key, $value, $exptime);
  88         }
  89
  90         function add($key, $value, $exptime=0) {
  91                 if( $this->get($key) == false ) {
  92                         $this->set($key, $value, $exptime);
  93                         return true;
  94                 }
  95         }
  96
  97         function add_multi($hash, $exptime=0) {
  98                 foreach($hash as $key => $value)
  99                         $this->add($key, $value, $exptime);
 100         }
 101
 102         function delete_multi($keys, $time=0) {
 103                 foreach($keys as $key)
 104                         $this->delete($key, $time);
 105         }
 106
 107         function replace($key, $value, $exptime=0) {
 108                 if( $this->get($key) !== false )
 109                         $this->set($key, $value, $exptime);
 110         }
 111
 112         function incr($key, $value=1) {
 113                 if ( !$this->lock($key) ) {
 114                         return false;
 115                 }
 116                 $value = intval($value);
 117                 if($value < 0) $value = 0;
 118
 119                 $n = false;
 120                 if( ($n = $this->get($key)) !== false ) {
 121                         $n += $value;
 122                         $this->set($key, $n); // exptime?
 123                 }
 124                 $this->unlock($key);
 125                 return $n;
 126         }
 127
 128         function decr($key, $value=1) {
 129                 if ( !$this->lock($key) ) {
 130                         return false;
 131                 }
 132                 $value = intval($value);
 133                 if($value < 0) $value = 0;
 134
 135                 $m = false;
 136                 if( ($n = $this->get($key)) !== false ) {
 137                         $m = $n - $value;
 138                         if($m < 0) $m = 0;
 139                         $this->set($key, $m); // exptime?
 140                 }
 141                 $this->unlock($key);
 142                 return $m;
 143         }
 144
 145         function _debug($text) {
 146                 if($this->debugmode)
 147                         wfDebug("BagOStuff debug: $text\n");
 148         }
 149
 150         /**
 151          * Convert an optionally relative time to an absolute time
 152          */
 153         static function convertExpiry( $exptime ) {
 154                 if(($exptime != 0) && ($exptime < 3600*24*30)) {
 155                         return time() + $exptime;
 156                 } else {
 157                         return $exptime;
 158                 }
 159         }
 160 }
 161
 162
 163 /**
 164  * Functional versions!
 165  * @todo document
 166  * @package MediaWiki
 167  */
 168 class HashBagOStuff extends BagOStuff {
 169         /*
 170            This is a test of the interface, mainly. It stores
 171            things in an associative array, which is not going to
 172            persist between program runs.
 173         */
 174         var $bag;
 175
 176         function HashBagOStuff() {
 177                 $this->bag = array();
 178         }
 179
 180         function _expire($key) {
 181                 $et = $this->bag[$key][1];
 182                 if(($et == 0) || ($et > time()))
 183                         return false;
 184                 $this->delete($key);
 185                 return true;
 186         }
 187
 188         function get($key) {
 189                 if(!$this->bag[$key])
 190                         return false;
 191                 if($this->_expire($key))
 192                         return false;
 193                 return $this->bag[$key][0];
 194         }
 195
 196         function set($key,$value,$exptime=0) {
 197                 $this->bag[$key] = array( $value, BagOStuff::convertExpiry( $exptime ) );
 198         }
 199
 200         function delete($key,$time=0) {
 201                 if(!$this->bag[$key])
 202                         return false;
 203                 unset($this->bag[$key]);
 204                 return true;
 205         }
 206 }
 207
 208 /*
 209 CREATE TABLE objectcache (
 210   keyname char(255) binary not null default '',
 211   value mediumblob,
 212   exptime datetime,
 213   unique key (keyname),
 214   key (exptime)
 215 );
 216 */
 217
 218 /**
 219  * @todo document
 220  * @abstract
 221  * @package MediaWiki
 222  */
 223 abstract class SqlBagOStuff extends BagOStuff {
 224         var $table;
 225         var $lastexpireall = 0;
 226
 227         function SqlBagOStuff($tablename = 'objectcache') {
 228                 $this->table = $tablename;
 229         }
 230
 231         function get($key) {
 232                 /* expire old entries if any */
 233                 $this->garbageCollect();
 234
 235                 $res = $this->_query(
 236                         "SELECT value,exptime FROM $0 WHERE keyname='$1'", $key);
 237                 if(!$res) {
 238                         $this->_debug("get: ** error: " . $this->_dberror($res) . " **");
 239                         return false;
 240                 }
 241                 if($row=$this->_fetchobject($res)) {
 242                         $this->_debug("get: retrieved data; exp time is " . $row->exptime);
 243                         if ( $row->exptime != $this->_maxdatetime() &&
 244                           wfTimestamp( TS_UNIX, $row->exptime ) < time() )
 245                         {
 246                                 $this->_debug("get: key has expired, deleting");
 247                                 $this->delete($key);
 248                                 return false;
 249                         }
 250                         return $this->_unserialize($this->_blobdecode($row->value));
 251                 } else {
 252                         $this->_debug('get: no matching rows');
 253                 }
 254                 return false;
 255         }
 256
 257         function set($key,$value,$exptime=0) {
 258                 $exptime = intval($exptime);
 259                 if($exptime < 0) $exptime = 0;
 260                 if($exptime == 0) {
 261                         $exp = $this->_maxdatetime();
 262                 } else {
 263                         if($exptime < 3.16e8) # ~10 years
 264                                 $exptime += time();
 265                         $exp = $this->_fromunixtime($exptime);
 266                 }
 267                 $this->delete( $key );
 268                 $this->_doinsert($this->getTableName(), array(
 269                                         'keyname' => $key,
 270                                         'value' => $this->_blobencode($this->_serialize($value)),
 271                                         'exptime' => $exp
 272                                 ));
 273                 return true; /* ? */
 274         }
 275
 276         function delete($key,$time=0) {
 277                 $this->_query(
 278                         "DELETE FROM $0 WHERE keyname='$1'", $key );
 279                 return true; /* ? */
 280         }
 281
 282         function getTableName() {
 283                 return $this->table;
 284         }
 285
 286         function _query($sql) {
 287                 $reps = func_get_args();
 288                 $reps[0] = $this->getTableName();
 289                 // ewwww
 290                 for($i=0;$i<count($reps);$i++) {
 291                         $sql = str_replace(
 292                                 '$' . $i,
 293                                 $i > 0 ? $this->_strencode($reps[$i]) : $reps[$i],
 294                                 $sql);
 295                 }
 296                 $res = $this->_doquery($sql);
 297                 if($res == false) {
 298                         $this->_debug('query failed: ' . $this->_dberror($res));
 299                 }
 300                 return $res;
 301         }
 302
 303         function _strencode($str) {
 304                 /* Protect strings in SQL */
 305                 return str_replace( "'", "''", $str );
 306         }
 307         function _blobencode($str) {
 308                 return $str;
 309         }
 310         function _blobdecode($str) {
 311                 return $str;
 312         }
 313
 314         abstract function _doinsert($table, $vals);
 315         abstract function _doquery($sql);
 316
 317         function _freeresult($result) {
 318                 /* stub */
 319                 return false;
 320         }
 321
 322         function _dberror($result) {
 323                 /* stub */
 324                 return 'unknown error';
 325         }
 326
 327         abstract function _maxdatetime();
 328         abstract function _fromunixtime($ts);
 329
 330         function garbageCollect() {
 331                 /* Ignore 99% of requests */
 332                 if ( !mt_rand( 0, 100 ) ) {
 333                         $nowtime = time();
 334                         /* Avoid repeating the delete within a few seconds */
 335                         if ( $nowtime > ($this->lastexpireall + 1) ) {
 336                                 $this->lastexpireall = $nowtime;
 337                                 $this->expireall();
 338                         }
 339                 }
 340         }
 341
 342         function expireall() {
 343                 /* Remove any items that have expired */
 344                 $now = $this->_fromunixtime( time() );
 345                 $this->_query( "DELETE FROM $0 WHERE exptime < '$now'" );
 346         }
 347
 348         function deleteall() {
 349                 /* Clear *all* items from cache table */
 350                 $this->_query( "DELETE FROM $0" );
 351         }
 352
 353         /**
 354          * Serialize an object and, if possible, compress the representation.
 355          * On typical message and page data, this can provide a 3X decrease
 356          * in storage requirements.
 357          *
 358          * @param mixed $data
 359          * @return string
 360          */
 361         function _serialize( &$data ) {
 362                 $serial = serialize( $data );
 363                 if( function_exists( 'gzdeflate' ) ) {
 364                         return gzdeflate( $serial );
 365                 } else {
 366                         return $serial;
 367                 }
 368         }
 369
 370         /**
 371          * Unserialize and, if necessary, decompress an object.
 372          * @param string $serial
 373          * @return mixed
 374          */
 375         function _unserialize( $serial ) {
 376                 if( function_exists( 'gzinflate' ) ) {
 377                         $decomp = @gzinflate( $serial );
 378                         if( false !== $decomp ) {
 379                                 $serial = $decomp;
 380                         }
 381                 }
 382                 $ret = unserialize( $serial );
 383                 return $ret;
 384         }
 385 }
 386
 387 /**
 388  * @todo document
 389  * @package MediaWiki
 390  */
 391 class MediaWikiBagOStuff extends SqlBagOStuff {
 392         var $tableInitialised = false;
 393
 394         function _doquery($sql) {
 395                 $dbw =& wfGetDB( DB_MASTER );
 396                 return $dbw->query($sql, 'MediaWikiBagOStuff::_doquery');
 397         }
 398         function _doinsert($t, $v) {
 399                 $dbw =& wfGetDB( DB_MASTER );
 400                 return $dbw->insert($t, $v, 'MediaWikiBagOStuff::_doinsert',
 401                         array( 'IGNORE' ) );
 402         }
 403         function _fetchobject($result) {
 404                 $dbw =& wfGetDB( DB_MASTER );
 405                 return $dbw->fetchObject($result);
 406         }
 407         function _freeresult($result) {
 408                 $dbw =& wfGetDB( DB_MASTER );
 409                 return $dbw->freeResult($result);
 410         }
 411         function _dberror($result) {
 412                 $dbw =& wfGetDB( DB_MASTER );
 413                 return $dbw->lastError();
 414         }
 415         function _maxdatetime() {
 416                 if ( time() > 0x7fffffff ) {
 417                         return $this->_fromunixtime( 1<<62 );
 418                 } else {
 419                         return $this->_fromunixtime( 0x7fffffff );
 420                 }
 421         }
 422         function _fromunixtime($ts) {
 423                 $dbw =& wfGetDB(DB_MASTER);
 424                 return $dbw->timestamp($ts);
 425         }
 426         function _strencode($s) {
 427                 $dbw =& wfGetDB( DB_MASTER );
 428                 return $dbw->strencode($s);
 429         }
 430         function _blobencode($s) {
 431                 $dbw =& wfGetDB( DB_MASTER );
 432                 return $dbw->encodeBlob($s);
 433         }
 434         function _blobdecode($s) {
 435                 $dbw =& wfGetDB( DB_MASTER );
 436                 return $dbw->decodeBlob($s);
 437         }
 438         function getTableName() {
 439                 if ( !$this->tableInitialised ) {
 440                         $dbw =& wfGetDB( DB_MASTER );
 441                         /* This is actually a hack, we should be able
 442                            to use Language classes here... or not */
 443                         if (!$dbw)
 444                                 throw new MWException("Could not connect to database");
 445                         $this->table = $dbw->tableName( $this->table );
 446                         $this->tableInitialised = true;
 447                 }
 448                 return $this->table;
 449         }
 450 }
 451
 452 /**
 453  * This is a wrapper for Turck MMCache's shared memory functions.
 454  *
 455  * You can store objects with mmcache_put() and mmcache_get(), but Turck seems
 456  * to use a weird custom serializer that randomly segfaults. So we wrap calls
 457  * with serialize()/unserialize().
 458  *
 459  * The thing I noticed about the Turck serialized data was that unlike ordinary
 460  * serialize(), it contained the names of methods, and judging by the amount of
 461  * binary data, perhaps even the bytecode of the methods themselves. It may be
 462  * that Turck's serializer is faster, so a possible future extension would be
 463  * to use it for arrays but not for objects.
 464  *
 465  * @package MediaWiki
 466  */
 467 class TurckBagOStuff extends BagOStuff {
 468         function get($key) {
 469                 $val = mmcache_get( $key );
 470                 if ( is_string( $val ) ) {
 471                         $val = unserialize( $val );
 472                 }
 473                 return $val;
 474         }
 475
 476         function set($key, $value, $exptime=0) {
 477                 mmcache_put( $key, serialize( $value ), $exptime );
 478                 return true;
 479         }
 480
 481         function delete($key, $time=0) {
 482                 mmcache_rm( $key );
 483                 return true;
 484         }
 485
 486         function lock($key, $waitTimeout = 0 ) {
 487                 mmcache_lock( $key );
 488                 return true;
 489         }
 490
 491         function unlock($key) {
 492                 mmcache_unlock( $key );
 493                 return true;
 494         }
 495 }
 496
 497 /**
 498  * This is a wrapper for APC's shared memory functions
 499  *
 500  * @package MediaWiki
 501  */
 502
 503 class APCBagOStuff extends BagOStuff {
 504         function get($key) {
 505                 $val = apc_fetch($key);
 506                 if ( is_string( $val ) ) {
 507                         $val = unserialize( $val );
 508                 }
 509                 return $val;
 510         }
 511
 512         function set($key, $value, $exptime=0) {
 513                 apc_store($key, serialize($value), $exptime);
 514                 return true;
 515         }
 516
 517         function delete($key, $time=0) {
 518                 apc_delete($key);
 519                 return true;
 520         }
 521 }
 522
 523
 524 /**
 525  * This is a wrapper for eAccelerator's shared memory functions.
 526  *
 527  * This is basically identical to the Turck MMCache version,
 528  * mostly because eAccelerator is based on Turck MMCache.
 529  *
 530  * @package MediaWiki
 531  */
 532 class eAccelBagOStuff extends BagOStuff {
 533         function get($key) {
 534                 $val = eaccelerator_get( $key );
 535                 if ( is_string( $val ) ) {
 536                         $val = unserialize( $val );
 537                 }
 538                 return $val;
 539         }
 540
 541         function set($key, $value, $exptime=0) {
 542                 eaccelerator_put( $key, serialize( $value ), $exptime );
 543                 return true;
 544         }
 545
 546         function delete($key, $time=0) {
 547                 eaccelerator_rm( $key );
 548                 return true;
 549         }
 550
 551         function lock($key, $waitTimeout = 0 ) {
 552                 eaccelerator_lock( $key );
 553                 return true;
 554         }
 555
 556         function unlock($key) {
 557                 eaccelerator_unlock( $key );
 558                 return true;
 559         }
 560 }
 561
 562 class DBABagOStuff extends BagOStuff {
 563         var $mHandler, $mFile, $mReader, $mWriter, $mDisabled;
 564
 565         function __construct( $handler = 'db3', $dir = false ) {
 566                 if ( $dir === false ) {
 567                         global $wgTmpDirectory;
 568                         $dir = $wgTmpDirectory;
 569                 }
 570                 $this->mFile = "$dir/mw-cache-" . wfWikiID();
 571                 $this->mFile .= '.db';
 572                 $this->mHandler = $handler;
 573         }
 574
 575         /**
 576          * Encode value and expiry for storage
 577          */
 578         function encode( $value, $expiry ) {
 579                 # Convert to absolute time
 580                 $expiry = BagOStuff::convertExpiry( $expiry );
 581                 return sprintf( '%010u', intval( $expiry ) ) . ' ' . serialize( $value );
 582         }
 583
 584         /**
 585          * @return list containing value first and expiry second
 586          */
 587         function decode( $blob ) {
 588                 if ( !is_string( $blob ) ) {
 589                         return array( null, 0 );
 590                 } else {
 591                         return array(
 592                                 unserialize( substr( $blob, 11 ) ),
 593                                 intval( substr( $blob, 0, 10 ) )
 594                         );
 595                 }
 596         }
 597
 598         function getReader() {
 599                 if ( file_exists( $this->mFile ) ) {
 600                         $handle = dba_open( $this->mFile, 'rl', $this->mHandler );
 601                 } else {
 602                         $handle = $this->getWriter();
 603                 }
 604                 if ( !$handle ) {
 605                         wfDebug( "Unable to open DBA cache file {$this->mFile}\n" );
 606                 }
 607                 return $handle;
 608         }
 609
 610         function getWriter() {
 611                 $handle = dba_open( $this->mFile, 'cl', $this->mHandler );
 612                 if ( !$handle ) {
 613                         wfDebug( "Unable to open DBA cache file {$this->mFile}\n" );
 614                 }
 615                 return $handle;
 616         }
 617
 618         function get( $key ) {
 619                 wfProfileIn( __METHOD__ );
 620                 wfDebug( __METHOD__."($key)\n" );
 621                 $handle = $this->getReader();
 622                 if ( !$handle ) {
 623                         return null;
 624                 }
 625                 $val = dba_fetch( $key, $handle );
 626                 list( $val, $expiry ) = $this->decode( $val );
 627                 # Must close ASAP because locks are held
 628                 dba_close( $handle );
 629
 630                 if ( !is_null( $val ) && $expiry && $expiry < time() ) {
 631                         # Key is expired, delete it
 632                         $handle = $this->getWriter();
 633                         dba_delete( $key, $handle );
 634                         dba_close( $handle );
 635                         wfDebug( __METHOD__.": $key expired\n" );
 636                         $val = null;
 637                 }
 638                 wfProfileOut( __METHOD__ );
 639                 return $val;
 640         }
 641
 642         function set( $key, $value, $exptime=0 ) {
 643                 wfProfileIn( __METHOD__ );
 644                 wfDebug( __METHOD__."($key)\n" );
 645                 $blob = $this->encode( $value, $exptime );
 646                 $handle = $this->getWriter();
 647                 if ( !$handle ) {
 648                         return false;
 649                 }
 650                 $ret = dba_replace( $key, $blob, $handle );
 651                 dba_close( $handle );
 652                 wfProfileOut( __METHOD__ );
 653                 return $ret;
 654         }
 655
 656         function delete( $key, $time = 0 ) {
 657                 wfProfileIn( __METHOD__ );
 658                 $handle = $this->getWriter();
 659                 if ( !$handle ) {
 660                         return false;
 661                 }
 662                 $ret = dba_delete( $key, $handle );
 663                 dba_close( $handle );
 664                 wfProfileOut( __METHOD__ );
 665                 return $ret;
 666         }
 667
 668         function add( $key, $value, $exptime = 0 ) {
 669                 wfProfileIn( __METHOD__ );
 670                 $blob = $this->encode( $value, $exptime );
 671                 $handle = $this->getWriter();
 672                 if ( !$handle ) {
 673                         return false;
 674                 }
 675                 $ret = dba_insert( $key, $blob, $handle );
 676                 # Insert failed, check to see if it failed due to an expired key
 677                 if ( !$ret ) {
 678                         list( $value, $expiry ) = $this->decode( dba_fetch( $key, $handle ) );
 679                         if ( $expiry < time() ) {
 680                                 # Yes expired, delete and try again
 681                                 dba_delete( $key, $handle );
 682                                 $ret = dba_insert( $key, $blob, $handle );
 683                                 # This time if it failed then it will be handled by the caller like any other race
 684                         }
 685                 }
 686
 687                 dba_close( $handle );
 688                 wfProfileOut( __METHOD__ );
 689                 return $ret;
 690         }
 691 }
 692
 693 ?>