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  * @defgroup Cache Cache
  23  *
  24  * @file
  25  * @ingroup Cache
  26  */
  27
  28 /**
  29  * interface is intended to be more or less compatible with
  30  * the PHP memcached client.
  31  *
  32  * backends for local hash array and SQL table included:
  33  * <code>
  34  *   $bag = new HashBagOStuff();
  35  *   $bag = new MediaWikiBagOStuff($tablename); # connect to db first
  36  * </code>
  37  *
  38  * @ingroup Cache
  39  */
  40 class BagOStuff {
  41         var $debugmode;
  42
  43         function __construct() {
  44                 $this->set_debug( false );
  45         }
  46
  47         function set_debug($bool) {
  48                 $this->debugmode = $bool;
  49         }
  50
  51         /* *** THE GUTS OF THE OPERATION *** */
  52         /* Override these with functional things in subclasses */
  53
  54         function get($key) {
  55                 /* stub */
  56                 return false;
  57         }
  58
  59         function set($key, $value, $exptime=0) {
  60                 /* stub */
  61                 return false;
  62         }
  63
  64         function delete($key, $time=0) {
  65                 /* stub */
  66                 return false;
  67         }
  68
  69         function lock($key, $timeout = 0) {
  70                 /* stub */
  71                 return true;
  72         }
  73
  74         function unlock($key) {
  75                 /* stub */
  76                 return true;
  77         }
  78
  79         function keys() {
  80                 /* stub */
  81                 return array();
  82         }
  83
  84         /* *** Emulated functions *** */
  85         /* Better performance can likely be got with custom written versions */
  86         function get_multi($keys) {
  87                 $out = array();
  88                 foreach($keys as $key)
  89                         $out[$key] = $this->get($key);
  90                 return $out;
  91         }
  92
  93         function set_multi($hash, $exptime=0) {
  94                 foreach($hash as $key => $value)
  95                         $this->set($key, $value, $exptime);
  96         }
  97
  98         function add($key, $value, $exptime=0) {
  99                 if( $this->get($key) == false ) {
 100                         $this->set($key, $value, $exptime);
 101                         return true;
 102                 }
 103         }
 104
 105         function add_multi($hash, $exptime=0) {
 106                 foreach($hash as $key => $value)
 107                         $this->add($key, $value, $exptime);
 108         }
 109
 110         function delete_multi($keys, $time=0) {
 111                 foreach($keys as $key)
 112                         $this->delete($key, $time);
 113         }
 114
 115         function replace($key, $value, $exptime=0) {
 116                 if( $this->get($key) !== false )
 117                         $this->set($key, $value, $exptime);
 118         }
 119
 120         function incr($key, $value=1) {
 121                 if ( !$this->lock($key) ) {
 122                         return false;
 123                 }
 124                 $value = intval($value);
 125                 if($value < 0) $value = 0;
 126
 127                 $n = false;
 128                 if( ($n = $this->get($key)) !== false ) {
 129                         $n += $value;
 130                         $this->set($key, $n); // exptime?
 131                 }
 132                 $this->unlock($key);
 133                 return $n;
 134         }
 135
 136         function decr($key, $value=1) {
 137                 if ( !$this->lock($key) ) {
 138                         return false;
 139                 }
 140                 $value = intval($value);
 141                 if($value < 0) $value = 0;
 142
 143                 $m = false;
 144                 if( ($n = $this->get($key)) !== false ) {
 145                         $m = $n - $value;
 146                         if($m < 0) $m = 0;
 147                         $this->set($key, $m); // exptime?
 148                 }
 149                 $this->unlock($key);
 150                 return $m;
 151         }
 152
 153         function _debug($text) {
 154                 if($this->debugmode)
 155                         wfDebug("BagOStuff debug: $text\n");
 156         }
 157
 158         /**
 159          * Convert an optionally relative time to an absolute time
 160          */
 161         static function convertExpiry( $exptime ) {
 162                 if(($exptime != 0) && ($exptime < 3600*24*30)) {
 163                         return time() + $exptime;
 164                 } else {
 165                         return $exptime;
 166                 }
 167         }
 168 }
 169
 170
 171 /**
 172  * Functional versions!
 173  * This is a test of the interface, mainly. It stores things in an associative
 174  * array, which is not going to persist between program runs.
 175  *
 176  * @ingroup Cache
 177  */
 178 class HashBagOStuff extends BagOStuff {
 179         var $bag;
 180
 181         function __construct() {
 182                 $this->bag = array();
 183         }
 184
 185         function _expire($key) {
 186                 $et = $this->bag[$key][1];
 187                 if(($et == 0) || ($et > time()))
 188                         return false;
 189                 $this->delete($key);
 190                 return true;
 191         }
 192
 193         function get($key) {
 194                 if(!$this->bag[$key])
 195                         return false;
 196                 if($this->_expire($key))
 197                         return false;
 198                 return $this->bag[$key][0];
 199         }
 200
 201         function set($key,$value,$exptime=0) {
 202                 $this->bag[$key] = array( $value, BagOStuff::convertExpiry( $exptime ) );
 203         }
 204
 205         function delete($key,$time=0) {
 206                 if(!$this->bag[$key])
 207                         return false;
 208                 unset($this->bag[$key]);
 209                 return true;
 210         }
 211
 212         function keys() {
 213                 return array_keys( $this->bag );
 214         }
 215 }
 216
 217 /**
 218  * Generic class to store objects in a database
 219  *
 220  * @ingroup Cache
 221  */
 222 abstract class SqlBagOStuff extends BagOStuff {
 223         var $table;
 224         var $lastexpireall = 0;
 225
 226         /**
 227          * Constructor
 228          *
 229          * @param $tablename String: name of the table to use
 230          */
 231         function __construct($tablename = 'objectcache') {
 232                 $this->table = $tablename;
 233         }
 234
 235         function get($key) {
 236                 /* expire old entries if any */
 237                 $this->garbageCollect();
 238
 239                 $res = $this->_query(
 240                         "SELECT value,exptime FROM $0 WHERE keyname='$1'", $key);
 241                 if(!$res) {
 242                         $this->_debug("get: ** error: " . $this->_dberror($res) . " **");
 243                         return false;
 244                 }
 245                 if($row=$this->_fetchobject($res)) {
 246                         $this->_debug("get: retrieved data; exp time is " . $row->exptime);
 247                         if ( $row->exptime != $this->_maxdatetime() &&
 248                           wfTimestamp( TS_UNIX, $row->exptime ) < time() )
 249                         {
 250                                 $this->_debug("get: key has expired, deleting");
 251                                 $this->delete($key);
 252                                 return false;
 253                         }
 254                         return $this->_unserialize($this->_blobdecode($row->value));
 255                 } else {
 256                         $this->_debug('get: no matching rows');
 257                 }
 258                 return false;
 259         }
 260
 261         function set($key,$value,$exptime=0) {
 262                 if ( $this->_readonly() ) {
 263                         return false;
 264                 }
 265                 $exptime = intval($exptime);
 266                 if($exptime < 0) $exptime = 0;
 267                 if($exptime == 0) {
 268                         $exp = $this->_maxdatetime();
 269                 } else {
 270                         if($exptime < 3.16e8) # ~10 years
 271                                 $exptime += time();
 272                         $exp = $this->_fromunixtime($exptime);
 273                 }
 274                 $this->delete( $key );
 275                 $this->_doinsert($this->getTableName(), array(
 276                                         'keyname' => $key,
 277                                         'value' => $this->_blobencode($this->_serialize($value)),
 278                                         'exptime' => $exp
 279                                 ));
 280                 return true; /* ? */
 281         }
 282
 283         function delete($key,$time=0) {
 284                 if ( $this->_readonly() ) {
 285                         return false;
 286                 }
 287                 $this->_query(
 288                         "DELETE FROM $0 WHERE keyname='$1'", $key );
 289                 return true; /* ? */
 290         }
 291
 292         function keys() {
 293                 $res = $this->_query( "SELECT keyname FROM $0" );
 294                 if(!$res) {
 295                         $this->_debug("keys: ** error: " . $this->_dberror($res) . " **");
 296                         return array();
 297                 }
 298                 $result = array();
 299                 while( $row = $this->_fetchobject($res) ) {
 300                         $result[] = $row->keyname;
 301                 }
 302                 return $result;
 303         }
 304
 305         function getTableName() {
 306                 return $this->table;
 307         }
 308
 309         function _query($sql) {
 310                 $reps = func_get_args();
 311                 $reps[0] = $this->getTableName();
 312                 // ewwww
 313                 for($i=0;$i<count($reps);$i++) {
 314                         $sql = str_replace(
 315                                 '$' . $i,
 316                                 $i > 0 ? $this->_strencode($reps[$i]) : $reps[$i],
 317                                 $sql);
 318                 }
 319                 $res = $this->_doquery($sql);
 320                 if($res == false) {
 321                         $this->_debug('query failed: ' . $this->_dberror($res));
 322                 }
 323                 return $res;
 324         }
 325
 326         function _strencode($str) {
 327                 /* Protect strings in SQL */
 328                 return str_replace( "'", "''", $str );
 329         }
 330         function _blobencode($str) {
 331                 return $str;
 332         }
 333         function _blobdecode($str) {
 334                 return $str;
 335         }
 336
 337         abstract function _doinsert($table, $vals);
 338         abstract function _doquery($sql);
 339
 340         abstract function _readonly();
 341
 342         function _freeresult($result) {
 343                 /* stub */
 344                 return false;
 345         }
 346
 347         function _dberror($result) {
 348                 /* stub */
 349                 return 'unknown error';
 350         }
 351
 352         abstract function _maxdatetime();
 353         abstract function _fromunixtime($ts);
 354
 355         function garbageCollect() {
 356                 /* Ignore 99% of requests */
 357                 if ( !mt_rand( 0, 100 ) ) {
 358                         $nowtime = time();
 359                         /* Avoid repeating the delete within a few seconds */
 360                         if ( $nowtime > ($this->lastexpireall + 1) ) {
 361                                 $this->lastexpireall = $nowtime;
 362                                 $this->expireall();
 363                         }
 364                 }
 365         }
 366
 367         function expireall() {
 368                 /* Remove any items that have expired */
 369                 if ( $this->_readonly() ) {
 370                         return false;
 371                 }
 372                 $now = $this->_fromunixtime( time() );
 373                 $this->_query( "DELETE FROM $0 WHERE exptime < '$now'" );
 374         }
 375
 376         function deleteall() {
 377                 /* Clear *all* items from cache table */
 378                 if ( $this->_readonly() ) {
 379                         return false;
 380                 }
 381                 $this->_query( "DELETE FROM $0" );
 382         }
 383
 384         /**
 385          * Serialize an object and, if possible, compress the representation.
 386          * On typical message and page data, this can provide a 3X decrease
 387          * in storage requirements.
 388          *
 389          * @param $data mixed
 390          * @return string
 391          */
 392         function _serialize( &$data ) {
 393                 $serial = serialize( $data );
 394                 if( function_exists( 'gzdeflate' ) ) {
 395                         return gzdeflate( $serial );
 396                 } else {
 397                         return $serial;
 398                 }
 399         }
 400
 401         /**
 402          * Unserialize and, if necessary, decompress an object.
 403          * @param $serial string
 404          * @return mixed
 405          */
 406         function _unserialize( $serial ) {
 407                 if( function_exists( 'gzinflate' ) ) {
 408                         $decomp = @gzinflate( $serial );
 409                         if( false !== $decomp ) {
 410                                 $serial = $decomp;
 411                         }
 412                 }
 413                 $ret = unserialize( $serial );
 414                 return $ret;
 415         }
 416 }
 417
 418 /**
 419  * Stores objects in the main database of the wiki
 420  *
 421  * @ingroup Cache
 422  */
 423 class MediaWikiBagOStuff extends SqlBagOStuff {
 424         var $tableInitialised = false;
 425
 426         function _getDB(){
 427                 static $db;
 428                 if( !isset( $db ) )
 429                         $db = wfGetDB( DB_MASTER );
 430                 return $db;
 431         }
 432         function _doquery($sql) {
 433                 return $this->_getDB()->query( $sql, __METHOD__ );
 434         }
 435         function _doinsert($t, $v) {
 436                 return $this->_getDB()->insert($t, $v, __METHOD__, array( 'IGNORE' ) );
 437         }
 438         function _fetchobject($result) {
 439                 return $this->_getDB()->fetchObject($result);
 440         }
 441         function _freeresult($result) {
 442                 return $this->_getDB()->freeResult($result);
 443         }
 444         function _dberror($result) {
 445                 return $this->_getDB()->lastError();
 446         }
 447         function _maxdatetime() {
 448                 if ( time() > 0x7fffffff ) {
 449                         return $this->_fromunixtime( 1<<62 );
 450                 } else {
 451                         return $this->_fromunixtime( 0x7fffffff );
 452                 }
 453         }
 454         function _fromunixtime($ts) {
 455                 return $this->_getDB()->timestamp($ts);
 456         }
 457         function _readonly(){
 458                 return wfReadOnly();
 459         }
 460         function _strencode($s) {
 461                 return $this->_getDB()->strencode($s);
 462         }
 463         function _blobencode($s) {
 464                 return $this->_getDB()->encodeBlob($s);
 465         }
 466         function _blobdecode($s) {
 467                 return $this->_getDB()->decodeBlob($s);
 468         }
 469         function getTableName() {
 470                 if ( !$this->tableInitialised ) {
 471                         $dbw = $this->_getDB();
 472                         /* This is actually a hack, we should be able
 473                            to use Language classes here... or not */
 474                         if (!$dbw)
 475                                 throw new MWException("Could not connect to database");
 476                         $this->table = $dbw->tableName( $this->table );
 477                         $this->tableInitialised = true;
 478                 }
 479                 return $this->table;
 480         }
 481 }
 482
 483 /**
 484  * This is a wrapper for Turck MMCache's shared memory functions.
 485  *
 486  * You can store objects with mmcache_put() and mmcache_get(), but Turck seems
 487  * to use a weird custom serializer that randomly segfaults. So we wrap calls
 488  * with serialize()/unserialize().
 489  *
 490  * The thing I noticed about the Turck serialized data was that unlike ordinary
 491  * serialize(), it contained the names of methods, and judging by the amount of
 492  * binary data, perhaps even the bytecode of the methods themselves. It may be
 493  * that Turck's serializer is faster, so a possible future extension would be
 494  * to use it for arrays but not for objects.
 495  *
 496  * @ingroup Cache
 497  */
 498 class TurckBagOStuff extends BagOStuff {
 499         function get($key) {
 500                 $val = mmcache_get( $key );
 501                 if ( is_string( $val ) ) {
 502                         $val = unserialize( $val );
 503                 }
 504                 return $val;
 505         }
 506
 507         function set($key, $value, $exptime=0) {
 508                 mmcache_put( $key, serialize( $value ), $exptime );
 509                 return true;
 510         }
 511
 512         function delete($key, $time=0) {
 513                 mmcache_rm( $key );
 514                 return true;
 515         }
 516
 517         function lock($key, $waitTimeout = 0 ) {
 518                 mmcache_lock( $key );
 519                 return true;
 520         }
 521
 522         function unlock($key) {
 523                 mmcache_unlock( $key );
 524                 return true;
 525         }
 526 }
 527
 528 /**
 529  * This is a wrapper for APC's shared memory functions
 530  *
 531  * @ingroup Cache
 532  */
 533 class APCBagOStuff extends BagOStuff {
 534         function get($key) {
 535                 $val = apc_fetch($key);
 536                 if ( is_string( $val ) ) {
 537                         $val = unserialize( $val );
 538                 }
 539                 return $val;
 540         }
 541
 542         function set($key, $value, $exptime=0) {
 543                 apc_store($key, serialize($value), $exptime);
 544                 return true;
 545         }
 546
 547         function delete($key, $time=0) {
 548                 apc_delete($key);
 549                 return true;
 550         }
 551 }
 552
 553
 554 /**
 555  * This is a wrapper for eAccelerator's shared memory functions.
 556  *
 557  * This is basically identical to the Turck MMCache version,
 558  * mostly because eAccelerator is based on Turck MMCache.
 559  *
 560  * @ingroup Cache
 561  */
 562 class eAccelBagOStuff extends BagOStuff {
 563         function get($key) {
 564                 $val = eaccelerator_get( $key );
 565                 if ( is_string( $val ) ) {
 566                         $val = unserialize( $val );
 567                 }
 568                 return $val;
 569         }
 570
 571         function set($key, $value, $exptime=0) {
 572                 eaccelerator_put( $key, serialize( $value ), $exptime );
 573                 return true;
 574         }
 575
 576         function delete($key, $time=0) {
 577                 eaccelerator_rm( $key );
 578                 return true;
 579         }
 580
 581         function lock($key, $waitTimeout = 0 ) {
 582                 eaccelerator_lock( $key );
 583                 return true;
 584         }
 585
 586         function unlock($key) {
 587                 eaccelerator_unlock( $key );
 588                 return true;
 589         }
 590 }
 591
 592 /**
 593  * Wrapper for XCache object caching functions; identical interface
 594  * to the APC wrapper
 595  *
 596  * @ingroup Cache
 597  */
 598 class XCacheBagOStuff extends BagOStuff {
 599
 600         /**
 601          * Get a value from the XCache object cache
 602          *
 603          * @param $key String: cache key
 604          * @return mixed
 605          */
 606         public function get( $key ) {
 607                 $val = xcache_get( $key );
 608                 if( is_string( $val ) )
 609                         $val = unserialize( $val );
 610                 return $val;
 611         }
 612
 613         /**
 614          * Store a value in the XCache object cache
 615          *
 616          * @param $key String: cache key
 617          * @param $value Mixed: object to store
 618          * @param $expire Int: expiration time
 619          * @return bool
 620          */
 621         public function set( $key, $value, $expire = 0 ) {
 622                 xcache_set( $key, serialize( $value ), $expire );
 623                 return true;
 624         }
 625
 626         /**
 627          * Remove a value from the XCache object cache
 628          *
 629          * @param $key String: cache key
 630          * @param $time Int: not used in this implementation
 631          * @return bool
 632          */
 633         public function delete( $key, $time = 0 ) {
 634                 xcache_unset( $key );
 635                 return true;
 636         }
 637
 638 }
 639
 640 /**
 641  * @todo document
 642  * @ingroup Cache
 643  */
 644 class DBABagOStuff extends BagOStuff {
 645         var $mHandler, $mFile, $mReader, $mWriter, $mDisabled;
 646
 647         function __construct( $handler = 'db3', $dir = false ) {
 648                 if ( $dir === false ) {
 649                         global $wgTmpDirectory;
 650                         $dir = $wgTmpDirectory;
 651                 }
 652                 $this->mFile = "$dir/mw-cache-" . wfWikiID();
 653                 $this->mFile .= '.db';
 654                 wfDebug( __CLASS__.": using cache file {$this->mFile}\n" );
 655                 $this->mHandler = $handler;
 656         }
 657
 658         /**
 659          * Encode value and expiry for storage
 660          */
 661         function encode( $value, $expiry ) {
 662                 # Convert to absolute time
 663                 $expiry = BagOStuff::convertExpiry( $expiry );
 664                 return sprintf( '%010u', intval( $expiry ) ) . ' ' . serialize( $value );
 665         }
 666
 667         /**
 668          * @return list containing value first and expiry second
 669          */
 670         function decode( $blob ) {
 671                 if ( !is_string( $blob ) ) {
 672                         return array( null, 0 );
 673                 } else {
 674                         return array(
 675                                 unserialize( substr( $blob, 11 ) ),
 676                                 intval( substr( $blob, 0, 10 ) )
 677                         );
 678                 }
 679         }
 680
 681         function getReader() {
 682                 if ( file_exists( $this->mFile ) ) {
 683                         $handle = dba_open( $this->mFile, 'rl', $this->mHandler );
 684                 } else {
 685                         $handle = $this->getWriter();
 686                 }
 687                 if ( !$handle ) {
 688                         wfDebug( "Unable to open DBA cache file {$this->mFile}\n" );
 689                 }
 690                 return $handle;
 691         }
 692
 693         function getWriter() {
 694                 $handle = dba_open( $this->mFile, 'cl', $this->mHandler );
 695                 if ( !$handle ) {
 696                         wfDebug( "Unable to open DBA cache file {$this->mFile}\n" );
 697                 }
 698                 return $handle;
 699         }
 700
 701         function get( $key ) {
 702                 wfProfileIn( __METHOD__ );
 703                 wfDebug( __METHOD__."($key)\n" );
 704                 $handle = $this->getReader();
 705                 if ( !$handle ) {
 706                         return null;
 707                 }
 708                 $val = dba_fetch( $key, $handle );
 709                 list( $val, $expiry ) = $this->decode( $val );
 710                 # Must close ASAP because locks are held
 711                 dba_close( $handle );
 712
 713                 if ( !is_null( $val ) && $expiry && $expiry < time() ) {
 714                         # Key is expired, delete it
 715                         $handle = $this->getWriter();
 716                         dba_delete( $key, $handle );
 717                         dba_close( $handle );
 718                         wfDebug( __METHOD__.": $key expired\n" );
 719                         $val = null;
 720                 }
 721                 wfProfileOut( __METHOD__ );
 722                 return $val;
 723         }
 724
 725         function set( $key, $value, $exptime=0 ) {
 726                 wfProfileIn( __METHOD__ );
 727                 wfDebug( __METHOD__."($key)\n" );
 728                 $blob = $this->encode( $value, $exptime );
 729                 $handle = $this->getWriter();
 730                 if ( !$handle ) {
 731                         return false;
 732                 }
 733                 $ret = dba_replace( $key, $blob, $handle );
 734                 dba_close( $handle );
 735                 wfProfileOut( __METHOD__ );
 736                 return $ret;
 737         }
 738
 739         function delete( $key, $time = 0 ) {
 740                 wfProfileIn( __METHOD__ );
 741                 wfDebug( __METHOD__."($key)\n" );
 742                 $handle = $this->getWriter();
 743                 if ( !$handle ) {
 744                         return false;
 745                 }
 746                 $ret = dba_delete( $key, $handle );
 747                 dba_close( $handle );
 748                 wfProfileOut( __METHOD__ );
 749                 return $ret;
 750         }
 751
 752         function add( $key, $value, $exptime = 0 ) {
 753                 wfProfileIn( __METHOD__ );
 754                 $blob = $this->encode( $value, $exptime );
 755                 $handle = $this->getWriter();
 756                 if ( !$handle ) {
 757                         return false;
 758                 }
 759                 $ret = dba_insert( $key, $blob, $handle );
 760                 # Insert failed, check to see if it failed due to an expired key
 761                 if ( !$ret ) {
 762                         list( $value, $expiry ) = $this->decode( dba_fetch( $key, $handle ) );
 763                         if ( $expiry < time() ) {
 764                                 # Yes expired, delete and try again
 765                                 dba_delete( $key, $handle );
 766                                 $ret = dba_insert( $key, $blob, $handle );
 767                                 # This time if it failed then it will be handled by the caller like any other race
 768                         }
 769                 }
 770
 771                 dba_close( $handle );
 772                 wfProfileOut( __METHOD__ );
 773                 return $ret;
 774         }
 775
 776         function keys() {
 777                 $reader = $this->getReader();
 778                 $k1 = dba_firstkey( $reader );
 779                 if( !$k1 ) {
 780                         return array();
 781                 }
 782                 $result[] = $k1;
 783                 while( $key = dba_nextkey( $reader ) ) {
 784                         $result[] = $key;
 785                 }
 786                 return $result;
 787         }
 788 }