includes/BagOStuff.php

   1 <?php
   2 /**
   3  * Classes to cache objects in PHP accelerators, SQL database or DBA files
   4  *
   5  * Copyright © 2003-2004 Brion Vibber <brion@pobox.com>
   6  * http://www.mediawiki.org/
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License along
  19  * with this program; if not, write to the Free Software Foundation, Inc.,
  20  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  21  * http://www.gnu.org/copyleft/gpl.html
  22  *
  23  * @file
  24  * @ingroup Cache
  25  */
  26
  27 /**
  28  * @defgroup Cache Cache
  29  */
  30
  31 /**
  32  * interface is intended to be more or less compatible with
  33  * the PHP memcached client.
  34  *
  35  * backends for local hash array and SQL table included:
  36  * <code>
  37  *   $bag = new HashBagOStuff();
  38  *   $bag = new SqlBagOStuff(); # connect to db first
  39  * </code>
  40  *
  41  * @ingroup Cache
  42  */
  43 abstract class BagOStuff {
  44         var $debugMode = false;
  45
  46         public function set_debug( $bool ) {
  47                 $this->debugMode = $bool;
  48         }
  49
  50         /* *** THE GUTS OF THE OPERATION *** */
  51         /* Override these with functional things in subclasses */
  52
  53         /**
  54          * Get an item with the given key. Returns false if it does not exist.
  55          * @param $key string
  56          */
  57         abstract public function get( $key );
  58
  59         /**
  60          * Set an item.
  61          * @param $key string
  62          * @param $value mixed
  63          * @param $exptime int Either an interval in seconds or a unix timestamp for expiry
  64          */
  65         abstract public function set( $key, $value, $exptime = 0 );
  66
  67         /*
  68          * Delete an item.
  69          * @param $key string
  70          * @param $time int Amount of time to delay the operation (mostly memcached-specific)
  71          */
  72         abstract public function delete( $key, $time = 0 );
  73
  74         public function lock( $key, $timeout = 0 ) {
  75                 /* stub */
  76                 return true;
  77         }
  78
  79         public function unlock( $key ) {
  80                 /* stub */
  81                 return true;
  82         }
  83
  84         public function keys() {
  85                 /* stub */
  86                 return array();
  87         }
  88
  89         /* *** Emulated functions *** */
  90         /* Better performance can likely be got with custom written versions */
  91         public function get_multi( $keys ) {
  92                 $out = array();
  93
  94                 foreach ( $keys as $key ) {
  95                         $out[$key] = $this->get( $key );
  96                 }
  97
  98                 return $out;
  99         }
 100
 101         public function set_multi( $hash, $exptime = 0 ) {
 102                 foreach ( $hash as $key => $value ) {
 103                         $this->set( $key, $value, $exptime );
 104                 }
 105         }
 106
 107         public function add( $key, $value, $exptime = 0 ) {
 108                 if ( !$this->get( $key ) ) {
 109                         $this->set( $key, $value, $exptime );
 110
 111                         return true;
 112                 }
 113         }
 114
 115         public function add_multi( $hash, $exptime = 0 ) {
 116                 foreach ( $hash as $key => $value ) {
 117                         $this->add( $key, $value, $exptime );
 118                 }
 119         }
 120
 121         public function delete_multi( $keys, $time = 0 ) {
 122                 foreach ( $keys as $key ) {
 123                         $this->delete( $key, $time );
 124                 }
 125         }
 126
 127         public function replace( $key, $value, $exptime = 0 ) {
 128                 if ( $this->get( $key ) !== false ) {
 129                         $this->set( $key, $value, $exptime );
 130                 }
 131         }
 132
 133         /**
 134          * @param $key String: Key yo increase
 135          * @param $value Integer: Value to add to $key (Default 1)
 136          * @return null if lock is not possible else $key value increased by $value
 137          */
 138         public function incr( $key, $value = 1 ) {
 139                 if ( !$this->lock( $key ) ) {
 140                         return null;
 141                 }
 142
 143                 $value = intval( $value );
 144
 145                 if ( ( $n = $this->get( $key ) ) !== false ) {
 146                         $n += $value;
 147                         $this->set( $key, $n ); // exptime?
 148                 }
 149                 $this->unlock( $key );
 150
 151                 return $n;
 152         }
 153
 154         public function decr( $key, $value = 1 ) {
 155                 return $this->incr( $key, - $value );
 156         }
 157
 158         public function debug( $text ) {
 159                 if ( $this->debugMode ) {
 160                         wfDebug( "BagOStuff debug: $text\n" );
 161                 }
 162         }
 163
 164         /**
 165          * Convert an optionally relative time to an absolute time
 166          */
 167         protected function convertExpiry( $exptime ) {
 168                 if ( ( $exptime != 0 ) && ( $exptime < 86400 * 3650 /* 10 years */ ) ) {
 169                         return time() + $exptime;
 170                 } else {
 171                         return $exptime;
 172                 }
 173         }
 174 }
 175
 176 /**
 177  * Functional versions!
 178  * This is a test of the interface, mainly. It stores things in an associative
 179  * array, which is not going to persist between program runs.
 180  *
 181  * @ingroup Cache
 182  */
 183 class HashBagOStuff extends BagOStuff {
 184         var $bag;
 185
 186         function __construct() {
 187                 $this->bag = array();
 188         }
 189
 190         protected function expire( $key ) {
 191                 $et = $this->bag[$key][1];
 192
 193                 if ( ( $et == 0 ) || ( $et > time() ) ) {
 194                         return false;
 195                 }
 196
 197                 $this->delete( $key );
 198
 199                 return true;
 200         }
 201
 202         function get( $key ) {
 203                 if ( !isset( $this->bag[$key] ) ) {
 204                         return false;
 205                 }
 206
 207                 if ( $this->expire( $key ) ) {
 208                         return false;
 209                 }
 210
 211                 return $this->bag[$key][0];
 212         }
 213
 214         function set( $key, $value, $exptime = 0 ) {
 215                 $this->bag[$key] = array( $value, $this->convertExpiry( $exptime ) );
 216         }
 217
 218         function delete( $key, $time = 0 ) {
 219                 if ( !isset( $this->bag[$key] ) ) {
 220                         return false;
 221                 }
 222
 223                 unset( $this->bag[$key] );
 224
 225                 return true;
 226         }
 227
 228         function keys() {
 229                 return array_keys( $this->bag );
 230         }
 231 }
 232
 233 /**
 234  * Class to store objects in the database
 235  *
 236  * @ingroup Cache
 237  */
 238 class SqlBagOStuff extends BagOStuff {
 239         var $lb, $db;
 240         var $lastExpireAll = 0;
 241
 242         protected function getDB() {
 243                 global $wgDBtype;
 244
 245                 if ( !isset( $this->db ) ) {
 246                         /* We must keep a separate connection to MySQL in order to avoid deadlocks
 247                          * However, SQLite has an opposite behaviour.
 248                          * @todo Investigate behaviour for other databases
 249                          */
 250                         if ( $wgDBtype == 'sqlite' ) {
 251                                 $this->db = wfGetDB( DB_MASTER );
 252                         } else {
 253                                 $this->lb = wfGetLBFactory()->newMainLB();
 254                                 $this->db = $this->lb->getConnection( DB_MASTER );
 255                                 $this->db->clearFlag( DBO_TRX );
 256                         }
 257                 }
 258
 259                 return $this->db;
 260         }
 261
 262         public function get( $key ) {
 263                 # expire old entries if any
 264                 $this->garbageCollect();
 265                 $db = $this->getDB();
 266                 $row = $db->selectRow( 'objectcache', array( 'value', 'exptime' ),
 267                         array( 'keyname' => $key ), __METHOD__ );
 268
 269                 if ( !$row ) {
 270                         $this->debug( 'get: no matching rows' );
 271                         return false;
 272                 }
 273
 274                 $this->debug( "get: retrieved data; expiry time is " . $row->exptime );
 275
 276                 if ( $this->isExpired( $row->exptime ) ) {
 277                         $this->debug( "get: key has expired, deleting" );
 278                         try {
 279                                 $db->begin();
 280                                 # Put the expiry time in the WHERE condition to avoid deleting a
 281                                 # newly-inserted value
 282                                 $db->delete( 'objectcache',
 283                                         array(
 284                                                 'keyname' => $key,
 285                                                 'exptime' => $row->exptime
 286                                         ), __METHOD__ );
 287                                 $db->commit();
 288                         } catch ( DBQueryError $e ) {
 289                                 $this->handleWriteError( $e );
 290                         }
 291
 292                         return false;
 293                 }
 294
 295                 return $this->unserialize( $db->decodeBlob( $row->value ) );
 296         }
 297
 298         public function set( $key, $value, $exptime = 0 ) {
 299                 $db = $this->getDB();
 300                 $exptime = intval( $exptime );
 301
 302                 if ( $exptime < 0 ) {
 303                         $exptime = 0;
 304                 }
 305
 306                 if ( $exptime == 0 ) {
 307                         $encExpiry = $this->getMaxDateTime();
 308                 } else {
 309                         if ( $exptime < 3.16e8 ) { # ~10 years
 310                                 $exptime += time();
 311                         }
 312
 313                         $encExpiry = $db->timestamp( $exptime );
 314                 }
 315                 try {
 316                         $db->begin();
 317                         // (bug 24425) use a replace if the db supports it instead of
 318                         // delete/insert to avoid clashes with conflicting keynames
 319                         $db->replace( 'objectcache', array( 'keyname' ),
 320                                 array(
 321                                         'keyname' => $key,
 322                                         'value' => $db->encodeBlob( $this->serialize( $value ) ),
 323                                         'exptime' => $encExpiry
 324                                 ), __METHOD__ );
 325                         $db->commit();
 326                 } catch ( DBQueryError $e ) {
 327                         $this->handleWriteError( $e );
 328
 329                         return false;
 330                 }
 331
 332                 return true;
 333         }
 334
 335         public function delete( $key, $time = 0 ) {
 336                 $db = $this->getDB();
 337
 338                 try {
 339                         $db->begin();
 340                         $db->delete( 'objectcache', array( 'keyname' => $key ), __METHOD__ );
 341                         $db->commit();
 342                 } catch ( DBQueryError $e ) {
 343                         $this->handleWriteError( $e );
 344
 345                         return false;
 346                 }
 347
 348                 return true;
 349         }
 350
 351         public function incr( $key, $step = 1 ) {
 352                 $db = $this->getDB();
 353                 $step = intval( $step );
 354
 355                 try {
 356                         $db->begin();
 357                         $row = $db->selectRow( 'objectcache', array( 'value', 'exptime' ),
 358                                 array( 'keyname' => $key ), __METHOD__, array( 'FOR UPDATE' ) );
 359                         if ( $row === false ) {
 360                                 // Missing
 361                                 $db->commit();
 362
 363                                 return null;
 364                         }
 365                         $db->delete( 'objectcache', array( 'keyname' => $key ), __METHOD__ );
 366                         if ( $this->isExpired( $row->exptime ) ) {
 367                                 // Expired, do not reinsert
 368                                 $db->commit();
 369
 370                                 return null;
 371                         }
 372
 373                         $oldValue = intval( $this->unserialize( $db->decodeBlob( $row->value ) ) );
 374                         $newValue = $oldValue + $step;
 375                         $db->insert( 'objectcache',
 376                                 array(
 377                                         'keyname' => $key,
 378                                         'value' => $db->encodeBlob( $this->serialize( $newValue ) ),
 379                                         'exptime' => $row->exptime
 380                                 ), __METHOD__ );
 381                         $db->commit();
 382                 } catch ( DBQueryError $e ) {
 383                         $this->handleWriteError( $e );
 384
 385                         return null;
 386                 }
 387
 388                 return $newValue;
 389         }
 390
 391         public function keys() {
 392                 $db = $this->getDB();
 393                 $res = $db->select( 'objectcache', array( 'keyname' ), false, __METHOD__ );
 394                 $result = array();
 395
 396                 foreach ( $res as $row ) {
 397                         $result[] = $row->keyname;
 398                 }
 399
 400                 return $result;
 401         }
 402
 403         protected function isExpired( $exptime ) {
 404                 return $exptime != $this->getMaxDateTime() && wfTimestamp( TS_UNIX, $exptime ) < time();
 405         }
 406
 407         protected function getMaxDateTime() {
 408                 if ( time() > 0x7fffffff ) {
 409                         return $this->getDB()->timestamp( 1 << 62 );
 410                 } else {
 411                         return $this->getDB()->timestamp( 0x7fffffff );
 412                 }
 413         }
 414
 415         protected function garbageCollect() {
 416                 /* Ignore 99% of requests */
 417                 if ( !mt_rand( 0, 100 ) ) {
 418                         $now = time();
 419                         /* Avoid repeating the delete within a few seconds */
 420                         if ( $now > ( $this->lastExpireAll + 1 ) ) {
 421                                 $this->lastExpireAll = $now;
 422                                 $this->expireAll();
 423                         }
 424                 }
 425         }
 426
 427         public function expireAll() {
 428                 $db = $this->getDB();
 429                 $now = $db->timestamp();
 430
 431                 try {
 432                         $db->begin();
 433                         $db->delete( 'objectcache', array( 'exptime < ' . $db->addQuotes( $now ) ), __METHOD__ );
 434                         $db->commit();
 435                 } catch ( DBQueryError $e ) {
 436                         $this->handleWriteError( $e );
 437                 }
 438         }
 439
 440         public function deleteAll() {
 441                 $db = $this->getDB();
 442
 443                 try {
 444                         $db->begin();
 445                         $db->delete( 'objectcache', '*', __METHOD__ );
 446                         $db->commit();
 447                 } catch ( DBQueryError $e ) {
 448                         $this->handleWriteError( $e );
 449                 }
 450         }
 451
 452         /**
 453          * Serialize an object and, if possible, compress the representation.
 454          * On typical message and page data, this can provide a 3X decrease
 455          * in storage requirements.
 456          *
 457          * @param $data mixed
 458          * @return string
 459          */
 460         protected function serialize( &$data ) {
 461                 $serial = serialize( $data );
 462
 463                 if ( function_exists( 'gzdeflate' ) ) {
 464                         return gzdeflate( $serial );
 465                 } else {
 466                         return $serial;
 467                 }
 468         }
 469
 470         /**
 471          * Unserialize and, if necessary, decompress an object.
 472          * @param $serial string
 473          * @return mixed
 474          */
 475         protected function unserialize( $serial ) {
 476                 if ( function_exists( 'gzinflate' ) ) {
 477                         $decomp = @gzinflate( $serial );
 478
 479                         if ( false !== $decomp ) {
 480                                 $serial = $decomp;
 481                         }
 482                 }
 483
 484                 $ret = unserialize( $serial );
 485
 486                 return $ret;
 487         }
 488
 489         /**
 490          * Handle a DBQueryError which occurred during a write operation.
 491          * Ignore errors which are due to a read-only database, rethrow others.
 492          */
 493         protected function handleWriteError( $exception ) {
 494                 $db = $this->getDB();
 495
 496                 if ( !$db->wasReadOnlyError() ) {
 497                         throw $exception;
 498                 }
 499
 500                 try {
 501                         $db->rollback();
 502                 } catch ( DBQueryError $e ) {
 503                 }
 504
 505                 wfDebug( __METHOD__ . ": ignoring query error\n" );
 506                 $db->ignoreErrors( false );
 507         }
 508 }
 509
 510 /**
 511  * Backwards compatibility alias
 512  */
 513 class MediaWikiBagOStuff extends SqlBagOStuff { }
 514
 515 /**
 516  * This is a wrapper for APC's shared memory functions
 517  *
 518  * @ingroup Cache
 519  */
 520 class APCBagOStuff extends BagOStuff {
 521         public function get( $key ) {
 522                 $val = apc_fetch( $key );
 523
 524                 if ( is_string( $val ) ) {
 525                         $val = unserialize( $val );
 526                 }
 527
 528                 return $val;
 529         }
 530
 531         public function set( $key, $value, $exptime = 0 ) {
 532                 apc_store( $key, serialize( $value ), $exptime );
 533
 534                 return true;
 535         }
 536
 537         public function delete( $key, $time = 0 ) {
 538                 apc_delete( $key );
 539
 540                 return true;
 541         }
 542
 543         public function keys() {
 544                 $info = apc_cache_info( 'user' );
 545                 $list = $info['cache_list'];
 546                 $keys = array();
 547
 548                 foreach ( $list as $entry ) {
 549                         $keys[] = $entry['info'];
 550                 }
 551
 552                 return $keys;
 553         }
 554 }
 555
 556 /**
 557  * This is a wrapper for eAccelerator's shared memory functions.
 558  *
 559  * This is basically identical to the deceased Turck MMCache version,
 560  * mostly because eAccelerator is based on Turck MMCache.
 561  *
 562  * @ingroup Cache
 563  */
 564 class eAccelBagOStuff extends BagOStuff {
 565         public function get( $key ) {
 566                 $val = eaccelerator_get( $key );
 567
 568                 if ( is_string( $val ) ) {
 569                         $val = unserialize( $val );
 570                 }
 571
 572                 return $val;
 573         }
 574
 575         public function set( $key, $value, $exptime = 0 ) {
 576                 eaccelerator_put( $key, serialize( $value ), $exptime );
 577
 578                 return true;
 579         }
 580
 581         public function delete( $key, $time = 0 ) {
 582                 eaccelerator_rm( $key );
 583
 584                 return true;
 585         }
 586
 587         public function lock( $key, $waitTimeout = 0 ) {
 588                 eaccelerator_lock( $key );
 589
 590                 return true;
 591         }
 592
 593         public function unlock( $key ) {
 594                 eaccelerator_unlock( $key );
 595
 596                 return true;
 597         }
 598 }
 599
 600 /**
 601  * Wrapper for XCache object caching functions; identical interface
 602  * to the APC wrapper
 603  *
 604  * @ingroup Cache
 605  */
 606 class XCacheBagOStuff extends BagOStuff {
 607         /**
 608          * Get a value from the XCache object cache
 609          *
 610          * @param $key String: cache key
 611          * @return mixed
 612          */
 613         public function get( $key ) {
 614                 $val = xcache_get( $key );
 615
 616                 if ( is_string( $val ) ) {
 617                         $val = unserialize( $val );
 618                 }
 619
 620                 return $val;
 621         }
 622
 623         /**
 624          * Store a value in the XCache object cache
 625          *
 626          * @param $key String: cache key
 627          * @param $value Mixed: object to store
 628          * @param $expire Int: expiration time
 629          * @return bool
 630          */
 631         public function set( $key, $value, $expire = 0 ) {
 632                 xcache_set( $key, serialize( $value ), $expire );
 633
 634                 return true;
 635         }
 636
 637         /**
 638          * Remove a value from the XCache object cache
 639          *
 640          * @param $key String: cache key
 641          * @param $time Int: not used in this implementation
 642          * @return bool
 643          */
 644         public function delete( $key, $time = 0 ) {
 645                 xcache_unset( $key );
 646
 647                 return true;
 648         }
 649 }
 650
 651 /**
 652  * Cache that uses DBA as a backend.
 653  * Slow due to the need to constantly open and close the file to avoid holding
 654  * writer locks. Intended for development use only,  as a memcached workalike
 655  * for systems that don't have it.
 656  *
 657  * @ingroup Cache
 658  */
 659 class DBABagOStuff extends BagOStuff {
 660         var $mHandler, $mFile, $mReader, $mWriter, $mDisabled;
 661
 662         public function __construct( $dir = false ) {
 663                 global $wgDBAhandler;
 664
 665                 if ( $dir === false ) {
 666                         global $wgTmpDirectory;
 667                         $dir = $wgTmpDirectory;
 668                 }
 669
 670                 $this->mFile = "$dir/mw-cache-" . wfWikiID();
 671                 $this->mFile .= '.db';
 672                 wfDebug( __CLASS__ . ": using cache file {$this->mFile}\n" );
 673                 $this->mHandler = $wgDBAhandler;
 674         }
 675
 676         /**
 677          * Encode value and expiry for storage
 678          */
 679         function encode( $value, $expiry ) {
 680                 # Convert to absolute time
 681                 $expiry = $this->convertExpiry( $expiry );
 682
 683                 return sprintf( '%010u', intval( $expiry ) ) . ' ' . serialize( $value );
 684         }
 685
 686         /**
 687          * @return list containing value first and expiry second
 688          */
 689         function decode( $blob ) {
 690                 if ( !is_string( $blob ) ) {
 691                         return array( null, 0 );
 692                 } else {
 693                         return array(
 694                                 unserialize( substr( $blob, 11 ) ),
 695                                 intval( substr( $blob, 0, 10 ) )
 696                         );
 697                 }
 698         }
 699
 700         function getReader() {
 701                 if ( file_exists( $this->mFile ) ) {
 702                         $handle = dba_open( $this->mFile, 'rl', $this->mHandler );
 703                 } else {
 704                         $handle = $this->getWriter();
 705                 }
 706
 707                 if ( !$handle ) {
 708                         wfDebug( "Unable to open DBA cache file {$this->mFile}\n" );
 709                 }
 710
 711                 return $handle;
 712         }
 713
 714         function getWriter() {
 715                 $handle = dba_open( $this->mFile, 'cl', $this->mHandler );
 716
 717                 if ( !$handle ) {
 718                         wfDebug( "Unable to open DBA cache file {$this->mFile}\n" );
 719                 }
 720
 721                 return $handle;
 722         }
 723
 724         function get( $key ) {
 725                 wfProfileIn( __METHOD__ );
 726                 wfDebug( __METHOD__ . "($key)\n" );
 727
 728                 $handle = $this->getReader();
 729                 if ( !$handle ) {
 730                         return null;
 731                 }
 732
 733                 $val = dba_fetch( $key, $handle );
 734                 list( $val, $expiry ) = $this->decode( $val );
 735
 736                 # Must close ASAP because locks are held
 737                 dba_close( $handle );
 738
 739                 if ( !is_null( $val ) && $expiry && $expiry < time() ) {
 740                         # Key is expired, delete it
 741                         $handle = $this->getWriter();
 742                         dba_delete( $key, $handle );
 743                         dba_close( $handle );
 744                         wfDebug( __METHOD__ . ": $key expired\n" );
 745                         $val = null;
 746                 }
 747
 748                 wfProfileOut( __METHOD__ );
 749                 return $val;
 750         }
 751
 752         function set( $key, $value, $exptime = 0 ) {
 753                 wfProfileIn( __METHOD__ );
 754                 wfDebug( __METHOD__ . "($key)\n" );
 755
 756                 $blob = $this->encode( $value, $exptime );
 757
 758                 $handle = $this->getWriter();
 759                 if ( !$handle ) {
 760                         return false;
 761                 }
 762
 763                 $ret = dba_replace( $key, $blob, $handle );
 764                 dba_close( $handle );
 765
 766                 wfProfileOut( __METHOD__ );
 767                 return $ret;
 768         }
 769
 770         function delete( $key, $time = 0 ) {
 771                 wfProfileIn( __METHOD__ );
 772                 wfDebug( __METHOD__ . "($key)\n" );
 773
 774                 $handle = $this->getWriter();
 775                 if ( !$handle ) {
 776                         return false;
 777                 }
 778
 779                 $ret = dba_delete( $key, $handle );
 780                 dba_close( $handle );
 781
 782                 wfProfileOut( __METHOD__ );
 783                 return $ret;
 784         }
 785
 786         function add( $key, $value, $exptime = 0 ) {
 787                 wfProfileIn( __METHOD__ );
 788
 789                 $blob = $this->encode( $value, $exptime );
 790
 791                 $handle = $this->getWriter();
 792
 793                 if ( !$handle ) {
 794                         return false;
 795                 }
 796
 797                 $ret = dba_insert( $key, $blob, $handle );
 798
 799                 # Insert failed, check to see if it failed due to an expired key
 800                 if ( !$ret ) {
 801                         list( $value, $expiry ) = $this->decode( dba_fetch( $key, $handle ) );
 802
 803                         if ( $expiry < time() ) {
 804                                 # Yes expired, delete and try again
 805                                 dba_delete( $key, $handle );
 806                                 $ret = dba_insert( $key, $blob, $handle );
 807                                 # This time if it failed then it will be handled by the caller like any other race
 808                         }
 809                 }
 810
 811                 dba_close( $handle );
 812
 813                 wfProfileOut( __METHOD__ );
 814                 return $ret;
 815         }
 816
 817         function keys() {
 818                 $reader = $this->getReader();
 819                 $k1 = dba_firstkey( $reader );
 820
 821                 if ( !$k1 ) {
 822                         return array();
 823                 }
 824
 825                 $result[] = $k1;
 826
 827                 while ( $key = dba_nextkey( $reader ) ) {
 828                         $result[] = $key;
 829                 }
 830
 831                 return $result;
 832         }
 833 }
 834
 835 /**
 836  * Wrapper for WinCache object caching functions; identical interface
 837  * to the APC wrapper
 838  *
 839  * @ingroup Cache
 840  */
 841 class WinCacheBagOStuff extends BagOStuff {
 842
 843         /**
 844          * Get a value from the WinCache object cache
 845          *
 846          * @param $key String: cache key
 847          * @return mixed
 848          */
 849         public function get( $key ) {
 850                 $val = wincache_ucache_get( $key );
 851
 852                 if ( is_string( $val ) ) {
 853                         $val = unserialize( $val );
 854                 }
 855
 856                 return $val;
 857         }
 858
 859         /**
 860          * Store a value in the WinCache object cache
 861          *
 862          * @param $key String: cache key
 863          * @param $value Mixed: object to store
 864          * @param $expire Int: expiration time
 865          * @return bool
 866          */
 867         public function set( $key, $value, $expire = 0 ) {
 868                 wincache_ucache_set( $key, serialize( $value ), $expire );
 869
 870                 return true;
 871         }
 872
 873         /**
 874          * Remove a value from the WinCache object cache
 875          *
 876          * @param $key String: cache key
 877          * @param $time Int: not used in this implementation
 878          * @return bool
 879          */
 880         public function delete( $key, $time = 0 ) {
 881                 wincache_ucache_delete( $key );
 882
 883                 return true;
 884         }
 885
 886         public function keys() {
 887                 $info = wincache_ucache_info();
 888                 $list = $info['ucache_entries'];
 889                 $keys = array();
 890
 891                 foreach ( $list as $entry ) {
 892                         $keys[] = $entry['key_name'];
 893                 }
 894
 895                 return $keys;
 896         }
 897 }