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