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  */
  23
  24 /**
  25  * Simple generic object store
  26  *
  27  * interface is intended to be more or less compatible with
  28  * the PHP memcached client.
  29  *
  30  * backends for local hash array and SQL table included:
  31  * <code>
  32  *   $bag = new HashBagOStuff();
  33  *   $bag = new MysqlBagOStuff($tablename); # connect to db first
  34  * </code>
  35  *
  36  */
  37 class BagOStuff {
  38         var $debugmode;
  39
  40         function __construct() {
  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  */
 167 class HashBagOStuff extends BagOStuff {
 168         /*
 169            This is a test of the interface, mainly. It stores
 170            things in an associative array, which is not going to
 171            persist between program runs.
 172         */
 173         var $bag;
 174
 175         function HashBagOStuff() {
 176                 $this->bag = array();
 177         }
 178
 179         function _expire($key) {
 180                 $et = $this->bag[$key][1];
 181                 if(($et == 0) || ($et > time()))
 182                         return false;
 183                 $this->delete($key);
 184                 return true;
 185         }
 186
 187         function get($key) {
 188                 if(!$this->bag[$key])
 189                         return false;
 190                 if($this->_expire($key))
 191                         return false;
 192                 return $this->bag[$key][0];
 193         }
 194
 195         function set($key,$value,$exptime=0) {
 196                 $this->bag[$key] = array( $value, BagOStuff::convertExpiry( $exptime ) );
 197         }
 198
 199         function delete($key,$time=0) {
 200                 if(!$this->bag[$key])
 201                         return false;
 202                 unset($this->bag[$key]);
 203                 return true;
 204         }
 205 }
 206
 207 /*
 208 CREATE TABLE objectcache (
 209   keyname char(255) binary not null default '',
 210   value mediumblob,
 211   exptime datetime,
 212   unique key (keyname),
 213   key (exptime)
 214 );
 215 */
 216
 217 /**
 218  * @todo document
 219  * @abstract
 220  */
 221 abstract class SqlBagOStuff extends BagOStuff {
 222         var $table;
 223         var $lastexpireall = 0;
 224
 225         function SqlBagOStuff($tablename = 'objectcache') {
 226                 $this->table = $tablename;
 227         }
 228
 229         function get($key) {
 230                 /* expire old entries if any */
 231                 $this->garbageCollect();
 232
 233                 $res = $this->_query(
 234                         "SELECT value,exptime FROM $0 WHERE keyname='$1'", $key);
 235                 if(!$res) {
 236                         $this->_debug("get: ** error: " . $this->_dberror($res) . " **");
 237                         return false;
 238                 }
 239                 if($row=$this->_fetchobject($res)) {
 240                         $this->_debug("get: retrieved data; exp time is " . $row->exptime);
 241                         if ( $row->exptime != $this->_maxdatetime() &&
 242                           wfTimestamp( TS_UNIX, $row->exptime ) < time() )
 243                         {
 244                                 $this->_debug("get: key has expired, deleting");
 245                                 $this->delete($key);
 246                                 return false;
 247                         }
 248                         return $this->_unserialize($this->_blobdecode($row->value));
 249                 } else {
 250                         $this->_debug('get: no matching rows');
 251                 }
 252                 return false;
 253         }
 254
 255         function set($key,$value,$exptime=0) {
 256                 $exptime = intval($exptime);
 257                 if($exptime < 0) $exptime = 0;
 258                 if($exptime == 0) {
 259                         $exp = $this->_maxdatetime();
 260                 } else {
 261                         if($exptime < 3.16e8) # ~10 years
 262                                 $exptime += time();
 263                         $exp = $this->_fromunixtime($exptime);
 264                 }
 265                 $this->delete( $key );
 266                 $this->_doinsert($this->getTableName(), array(
 267                                         'keyname' => $key,
 268                                         'value' => $this->_blobencode($this->_serialize($value)),
 269                                         'exptime' => $exp
 270                                 ));
 271                 return true; /* ? */
 272         }
 273
 274         function delete($key,$time=0) {
 275                 $this->_query(
 276                         "DELETE FROM $0 WHERE keyname='$1'", $key );
 277                 return true; /* ? */
 278         }
 279
 280         function getTableName() {
 281                 return $this->table;
 282         }
 283
 284         function _query($sql) {
 285                 $reps = func_get_args();
 286                 $reps[0] = $this->getTableName();
 287                 // ewwww
 288                 for($i=0;$i<count($reps);$i++) {
 289                         $sql = str_replace(
 290                                 '$' . $i,
 291                                 $i > 0 ? $this->_strencode($reps[$i]) : $reps[$i],
 292                                 $sql);
 293                 }
 294                 $res = $this->_doquery($sql);
 295                 if($res == false) {
 296                         $this->_debug('query failed: ' . $this->_dberror($res));
 297                 }
 298                 return $res;
 299         }
 300
 301         function _strencode($str) {
 302                 /* Protect strings in SQL */
 303                 return str_replace( "'", "''", $str );
 304         }
 305         function _blobencode($str) {
 306                 return $str;
 307         }
 308         function _blobdecode($str) {
 309                 return $str;
 310         }
 311
 312         abstract function _doinsert($table, $vals);
 313         abstract function _doquery($sql);
 314
 315         function _freeresult($result) {
 316                 /* stub */
 317                 return false;
 318         }
 319
 320         function _dberror($result) {
 321                 /* stub */
 322                 return 'unknown error';
 323         }
 324
 325         abstract function _maxdatetime();
 326         abstract function _fromunixtime($ts);
 327
 328         function garbageCollect() {
 329                 /* Ignore 99% of requests */
 330                 if ( !mt_rand( 0, 100 ) ) {
 331                         $nowtime = time();
 332                         /* Avoid repeating the delete within a few seconds */
 333                         if ( $nowtime > ($this->lastexpireall + 1) ) {
 334                                 $this->lastexpireall = $nowtime;
 335                                 $this->expireall();
 336                         }
 337                 }
 338         }
 339
 340         function expireall() {
 341                 /* Remove any items that have expired */
 342                 $now = $this->_fromunixtime( time() );
 343                 $this->_query( "DELETE FROM $0 WHERE exptime < '$now'" );
 344         }
 345
 346         function deleteall() {
 347                 /* Clear *all* items from cache table */
 348                 $this->_query( "DELETE FROM $0" );
 349         }
 350
 351         /**
 352          * Serialize an object and, if possible, compress the representation.
 353          * On typical message and page data, this can provide a 3X decrease
 354          * in storage requirements.
 355          *
 356          * @param mixed $data
 357          * @return string
 358          */
 359         function _serialize( &$data ) {
 360                 $serial = serialize( $data );
 361                 if( function_exists( 'gzdeflate' ) ) {
 362                         return gzdeflate( $serial );
 363                 } else {
 364                         return $serial;
 365                 }
 366         }
 367
 368         /**
 369          * Unserialize and, if necessary, decompress an object.
 370          * @param string $serial
 371          * @return mixed
 372          */
 373         function _unserialize( $serial ) {
 374                 if( function_exists( 'gzinflate' ) ) {
 375                         $decomp = @gzinflate( $serial );
 376                         if( false !== $decomp ) {
 377                                 $serial = $decomp;
 378                         }
 379                 }
 380                 $ret = unserialize( $serial );
 381                 return $ret;
 382         }
 383 }
 384
 385 /**
 386  * @todo document
 387  */
 388 class MediaWikiBagOStuff extends SqlBagOStuff {
 389         var $tableInitialised = false;
 390
 391         function _doquery($sql) {
 392                 $dbw = wfGetDB( DB_MASTER );
 393                 return $dbw->query($sql, 'MediaWikiBagOStuff::_doquery');
 394         }
 395         function _doinsert($t, $v) {
 396                 $dbw = wfGetDB( DB_MASTER );
 397                 return $dbw->insert($t, $v, 'MediaWikiBagOStuff::_doinsert',
 398                         array( 'IGNORE' ) );
 399         }
 400         function _fetchobject($result) {
 401                 $dbw = wfGetDB( DB_MASTER );
 402                 return $dbw->fetchObject($result);
 403         }
 404         function _freeresult($result) {
 405                 $dbw = wfGetDB( DB_MASTER );
 406                 return $dbw->freeResult($result);
 407         }
 408         function _dberror($result) {
 409                 $dbw = wfGetDB( DB_MASTER );
 410                 return $dbw->lastError();
 411         }
 412         function _maxdatetime() {
 413                 if ( time() > 0x7fffffff ) {
 414                         return $this->_fromunixtime( 1<<62 );
 415                 } else {
 416                         return $this->_fromunixtime( 0x7fffffff );
 417                 }
 418         }
 419         function _fromunixtime($ts) {
 420                 $dbw = wfGetDB(DB_MASTER);
 421                 return $dbw->timestamp($ts);
 422         }
 423         function _strencode($s) {
 424                 $dbw = wfGetDB( DB_MASTER );
 425                 return $dbw->strencode($s);
 426         }
 427         function _blobencode($s) {
 428                 $dbw = wfGetDB( DB_MASTER );
 429                 return $dbw->encodeBlob($s);
 430         }
 431         function _blobdecode($s) {
 432                 $dbw = wfGetDB( DB_MASTER );
 433                 return $dbw->decodeBlob($s);
 434         }
 435         function getTableName() {
 436                 if ( !$this->tableInitialised ) {
 437                         $dbw = wfGetDB( DB_MASTER );
 438                         /* This is actually a hack, we should be able
 439                            to use Language classes here... or not */
 440                         if (!$dbw)
 441                                 throw new MWException("Could not connect to database");
 442                         $this->table = $dbw->tableName( $this->table );
 443                         $this->tableInitialised = true;
 444                 }
 445                 return $this->table;
 446         }
 447 }
 448
 449 /**
 450  * This is a wrapper for Turck MMCache's shared memory functions.
 451  *
 452  * You can store objects with mmcache_put() and mmcache_get(), but Turck seems
 453  * to use a weird custom serializer that randomly segfaults. So we wrap calls
 454  * with serialize()/unserialize().
 455  *
 456  * The thing I noticed about the Turck serialized data was that unlike ordinary
 457  * serialize(), it contained the names of methods, and judging by the amount of
 458  * binary data, perhaps even the bytecode of the methods themselves. It may be
 459  * that Turck's serializer is faster, so a possible future extension would be
 460  * to use it for arrays but not for objects.
 461  *
 462  */
 463 class TurckBagOStuff extends BagOStuff {
 464         function get($key) {
 465                 $val = mmcache_get( $key );
 466                 if ( is_string( $val ) ) {
 467                         $val = unserialize( $val );
 468                 }
 469                 return $val;
 470         }
 471
 472         function set($key, $value, $exptime=0) {
 473                 mmcache_put( $key, serialize( $value ), $exptime );
 474                 return true;
 475         }
 476
 477         function delete($key, $time=0) {
 478                 mmcache_rm( $key );
 479                 return true;
 480         }
 481
 482         function lock($key, $waitTimeout = 0 ) {
 483                 mmcache_lock( $key );
 484                 return true;
 485         }
 486
 487         function unlock($key) {
 488                 mmcache_unlock( $key );
 489                 return true;
 490         }
 491 }
 492
 493 /**
 494  * This is a wrapper for APC's shared memory functions
 495  *
 496  */
 497 class APCBagOStuff extends BagOStuff {
 498         function get($key) {
 499                 $val = apc_fetch($key);
 500                 if ( is_string( $val ) ) {
 501                         $val = unserialize( $val );
 502                 }
 503                 return $val;
 504         }
 505
 506         function set($key, $value, $exptime=0) {
 507                 apc_store($key, serialize($value), $exptime);
 508                 return true;
 509         }
 510
 511         function delete($key, $time=0) {
 512                 apc_delete($key);
 513                 return true;
 514         }
 515 }
 516
 517
 518 /**
 519  * This is a wrapper for eAccelerator's shared memory functions.
 520  *
 521  * This is basically identical to the Turck MMCache version,
 522  * mostly because eAccelerator is based on Turck MMCache.
 523  *
 524  */
 525 class eAccelBagOStuff extends BagOStuff {
 526         function get($key) {
 527                 $val = eaccelerator_get( $key );
 528                 if ( is_string( $val ) ) {
 529                         $val = unserialize( $val );
 530                 }
 531                 return $val;
 532         }
 533
 534         function set($key, $value, $exptime=0) {
 535                 eaccelerator_put( $key, serialize( $value ), $exptime );
 536                 return true;
 537         }
 538
 539         function delete($key, $time=0) {
 540                 eaccelerator_rm( $key );
 541                 return true;
 542         }
 543
 544         function lock($key, $waitTimeout = 0 ) {
 545                 eaccelerator_lock( $key );
 546                 return true;
 547         }
 548
 549         function unlock($key) {
 550                 eaccelerator_unlock( $key );
 551                 return true;
 552         }
 553 }
 554
 555 /**
 556  * @todo document
 557  */
 558 class DBABagOStuff extends BagOStuff {
 559         var $mHandler, $mFile, $mReader, $mWriter, $mDisabled;
 560
 561         function __construct( $handler = 'db3', $dir = false ) {
 562                 if ( $dir === false ) {
 563                         global $wgTmpDirectory;
 564                         $dir = $wgTmpDirectory;
 565                 }
 566                 $this->mFile = "$dir/mw-cache-" . wfWikiID();
 567                 $this->mFile .= '.db';
 568                 $this->mHandler = $handler;
 569         }
 570
 571         /**
 572          * Encode value and expiry for storage
 573          */
 574         function encode( $value, $expiry ) {
 575                 # Convert to absolute time
 576                 $expiry = BagOStuff::convertExpiry( $expiry );
 577                 return sprintf( '%010u', intval( $expiry ) ) . ' ' . serialize( $value );
 578         }
 579
 580         /**
 581          * @return list containing value first and expiry second
 582          */
 583         function decode( $blob ) {
 584                 if ( !is_string( $blob ) ) {
 585                         return array( null, 0 );
 586                 } else {
 587                         return array(
 588                                 unserialize( substr( $blob, 11 ) ),
 589                                 intval( substr( $blob, 0, 10 ) )
 590                         );
 591                 }
 592         }
 593
 594         function getReader() {
 595                 if ( file_exists( $this->mFile ) ) {
 596                         $handle = dba_open( $this->mFile, 'rl', $this->mHandler );
 597                 } else {
 598                         $handle = $this->getWriter();
 599                 }
 600                 if ( !$handle ) {
 601                         wfDebug( "Unable to open DBA cache file {$this->mFile}\n" );
 602                 }
 603                 return $handle;
 604         }
 605
 606         function getWriter() {
 607                 $handle = dba_open( $this->mFile, 'cl', $this->mHandler );
 608                 if ( !$handle ) {
 609                         wfDebug( "Unable to open DBA cache file {$this->mFile}\n" );
 610                 }
 611                 return $handle;
 612         }
 613
 614         function get( $key ) {
 615                 wfProfileIn( __METHOD__ );
 616                 wfDebug( __METHOD__."($key)\n" );
 617                 $handle = $this->getReader();
 618                 if ( !$handle ) {
 619                         return null;
 620                 }
 621                 $val = dba_fetch( $key, $handle );
 622                 list( $val, $expiry ) = $this->decode( $val );
 623                 # Must close ASAP because locks are held
 624                 dba_close( $handle );
 625
 626                 if ( !is_null( $val ) && $expiry && $expiry < time() ) {
 627                         # Key is expired, delete it
 628                         $handle = $this->getWriter();
 629                         dba_delete( $key, $handle );
 630                         dba_close( $handle );
 631                         wfDebug( __METHOD__.": $key expired\n" );
 632                         $val = null;
 633                 }
 634                 wfProfileOut( __METHOD__ );
 635                 return $val;
 636         }
 637
 638         function set( $key, $value, $exptime=0 ) {
 639                 wfProfileIn( __METHOD__ );
 640                 wfDebug( __METHOD__."($key)\n" );
 641                 $blob = $this->encode( $value, $exptime );
 642                 $handle = $this->getWriter();
 643                 if ( !$handle ) {
 644                         return false;
 645                 }
 646                 $ret = dba_replace( $key, $blob, $handle );
 647                 dba_close( $handle );
 648                 wfProfileOut( __METHOD__ );
 649                 return $ret;
 650         }
 651
 652         function delete( $key, $time = 0 ) {
 653                 wfProfileIn( __METHOD__ );
 654                 $handle = $this->getWriter();
 655                 if ( !$handle ) {
 656                         return false;
 657                 }
 658                 $ret = dba_delete( $key, $handle );
 659                 dba_close( $handle );
 660                 wfProfileOut( __METHOD__ );
 661                 return $ret;
 662         }
 663
 664         function add( $key, $value, $exptime = 0 ) {
 665                 wfProfileIn( __METHOD__ );
 666                 $blob = $this->encode( $value, $exptime );
 667                 $handle = $this->getWriter();
 668                 if ( !$handle ) {
 669                         return false;
 670                 }
 671                 $ret = dba_insert( $key, $blob, $handle );
 672                 # Insert failed, check to see if it failed due to an expired key
 673                 if ( !$ret ) {
 674                         list( $value, $expiry ) = $this->decode( dba_fetch( $key, $handle ) );
 675                         if ( $expiry < time() ) {
 676                                 # Yes expired, delete and try again
 677                                 dba_delete( $key, $handle );
 678                                 $ret = dba_insert( $key, $blob, $handle );
 679                                 # This time if it failed then it will be handled by the caller like any other race
 680                         }
 681                 }
 682
 683                 dba_close( $handle );
 684                 wfProfileOut( __METHOD__ );
 685                 return $ret;
 686         }
 687 }
 688
 689 ?>