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         public function incr( $key, $value = 1 ) {
 134                 if ( !$this->lock( $key ) ) {
 135                         return false;
 136                 }
 137
 138                 $value = intval( $value );
 139
 140                 if ( ( $n = $this->get( $key ) ) !== false ) {
 141                         $n += $value;
 142                         $this->set( $key, $n ); // exptime?
 143                 }
 144                 $this->unlock( $key );
 145
 146                 return $n;
 147         }
 148
 149         public function decr( $key, $value = 1 ) {
 150                 return $this->incr( $key, - $value );
 151         }
 152
 153         public function debug( $text ) {
 154                 if ( $this->debugMode ) {
 155                         wfDebug( "BagOStuff debug: $text\n" );
 156                 }
 157         }
 158
 159         /**
 160          * Convert an optionally relative time to an absolute time
 161          */
 162         protected function convertExpiry( $exptime ) {
 163                 if ( ( $exptime != 0 ) && ( $exptime < 86400 * 3650 /* 10 years */ ) ) {
 164                         return time() + $exptime;
 165                 } else {
 166                         return $exptime;
 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         protected function expire( $key ) {
 186                 $et = $this->bag[$key][1];
 187
 188                 if ( ( $et == 0 ) || ( $et > time() ) ) {
 189                         return false;
 190                 }
 191
 192                 $this->delete( $key );
 193
 194                 return true;
 195         }
 196
 197         function get( $key ) {
 198                 if ( !isset( $this->bag[$key] ) ) {
 199                         return false;
 200                 }
 201
 202                 if ( $this->expire( $key ) ) {
 203                         return false;
 204                 }
 205
 206                 return $this->bag[$key][0];
 207         }
 208
 209         function set( $key, $value, $exptime = 0 ) {
 210                 $this->bag[$key] = array( $value, $this->convertExpiry( $exptime ) );
 211         }
 212
 213         function delete( $key, $time = 0 ) {
 214                 if ( !isset( $this->bag[$key] ) ) {
 215                         return false;
 216                 }
 217
 218                 unset( $this->bag[$key] );
 219
 220                 return true;
 221         }
 222
 223         function keys() {
 224                 return array_keys( $this->bag );
 225         }
 226 }
 227
 228 /**
 229  * Class to store objects in the database
 230  *
 231  * @ingroup Cache
 232  */
 233 class SqlBagOStuff extends BagOStuff {
 234         var $lb, $db;
 235         var $lastExpireAll = 0;
 236
 237         protected function getDB() {
 238                 global $wgDBtype;
 239
 240                 if ( !isset( $this->db ) ) {
 241                         /* We must keep a separate connection to MySQL in order to avoid deadlocks
 242                          * However, SQLite has an opposite behaviour.
 243                          * @todo Investigate behaviour for other databases
 244                          */
 245                         if ( $wgDBtype == 'sqlite' ) {
 246                                 $this->db = wfGetDB( DB_MASTER );
 247                         } else {
 248                                 $this->lb = wfGetLBFactory()->newMainLB();
 249                                 $this->db = $this->lb->getConnection( DB_MASTER );
 250                                 $this->db->clearFlag( DBO_TRX );
 251                         }
 252                 }
 253
 254                 return $this->db;
 255         }
 256
 257         public function get( $key ) {
 258                 # expire old entries if any
 259                 $this->garbageCollect();
 260                 $db = $this->getDB();
 261                 $row = $db->selectRow( 'objectcache', array( 'value', 'exptime' ),
 262                         array( 'keyname' => $key ), __METHOD__ );
 263
 264                 if ( !$row ) {
 265                         $this->debug( 'get: no matching rows' );
 266                         return false;
 267                 }
 268
 269                 $this->debug( "get: retrieved data; expiry time is " . $row->exptime );
 270
 271                 if ( $this->isExpired( $row->exptime ) ) {
 272                         $this->debug( "get: key has expired, deleting" );
 273                         try {
 274                                 $db->begin();
 275                                 # Put the expiry time in the WHERE condition to avoid deleting a
 276                                 # newly-inserted value
 277                                 $db->delete( 'objectcache',
 278                                         array(
 279                                                 'keyname' => $key,
 280                                                 'exptime' => $row->exptime
 281                                         ), __METHOD__ );
 282                                 $db->commit();
 283                         } catch ( DBQueryError $e ) {
 284                                 $this->handleWriteError( $e );
 285                         }
 286
 287                         return false;
 288                 }
 289
 290                 return $this->unserialize( $db->decodeBlob( $row->value ) );
 291         }
 292
 293         public function set( $key, $value, $exptime = 0 ) {
 294                 $db = $this->getDB();
 295                 $exptime = intval( $exptime );
 296
 297                 if ( $exptime < 0 ) {
 298                         $exptime = 0;
 299                 }
 300
 301                 if ( $exptime == 0 ) {
 302                         $encExpiry = $this->getMaxDateTime();
 303                 } else {
 304                         if ( $exptime < 3.16e8 ) { # ~10 years
 305                                 $exptime += time();
 306                         }
 307
 308                         $encExpiry = $db->timestamp( $exptime );
 309                 }
 310                 try {
 311                         $db->begin();
 312                         // (bug 24425) use a replace if the db supports it instead of
 313                         // delete/insert to avoid clashes with conflicting keynames
 314                         $db->replace( 'objectcache', array( 'keyname' ),
 315                                 array(
 316                                         'keyname' => $key,
 317                                         'value' => $db->encodeBlob( $this->serialize( $value ) ),
 318                                         'exptime' => $encExpiry
 319                                 ), __METHOD__ );
 320                         $db->commit();
 321                 } catch ( DBQueryError $e ) {
 322                         $this->handleWriteError( $e );
 323
 324                         return false;
 325                 }
 326
 327                 return true;
 328         }
 329
 330         public function delete( $key, $time = 0 ) {
 331                 $db = $this->getDB();
 332
 333                 try {
 334                         $db->begin();
 335                         $db->delete( 'objectcache', array( 'keyname' => $key ), __METHOD__ );
 336                         $db->commit();
 337                 } catch ( DBQueryError $e ) {
 338                         $this->handleWriteError( $e );
 339
 340                         return false;
 341                 }
 342
 343                 return true;
 344         }
 345
 346         public function incr( $key, $step = 1 ) {
 347                 $db = $this->getDB();
 348                 $step = intval( $step );
 349
 350                 try {
 351                         $db->begin();
 352                         $row = $db->selectRow( 'objectcache', array( 'value', 'exptime' ),
 353                                 array( 'keyname' => $key ), __METHOD__, array( 'FOR UPDATE' ) );
 354                         if ( $row === false ) {
 355                                 // Missing
 356                                 $db->commit();
 357
 358                                 return null;
 359                         }
 360                         $db->delete( 'objectcache', array( 'keyname' => $key ), __METHOD__ );
 361                         if ( $this->isExpired( $row->exptime ) ) {
 362                                 // Expired, do not reinsert
 363                                 $db->commit();
 364
 365                                 return null;
 366                         }
 367
 368                         $oldValue = intval( $this->unserialize( $db->decodeBlob( $row->value ) ) );
 369                         $newValue = $oldValue + $step;
 370                         $db->insert( 'objectcache',
 371                                 array(
 372                                         'keyname' => $key,
 373                                         'value' => $db->encodeBlob( $this->serialize( $newValue ) ),
 374                                         'exptime' => $row->exptime
 375                                 ), __METHOD__ );
 376                         $db->commit();
 377                 } catch ( DBQueryError $e ) {
 378                         $this->handleWriteError( $e );
 379
 380                         return null;
 381                 }
 382
 383                 return $newValue;
 384         }
 385
 386         public function keys() {
 387                 $db = $this->getDB();
 388                 $res = $db->select( 'objectcache', array( 'keyname' ), false, __METHOD__ );
 389                 $result = array();
 390
 391                 foreach ( $res as $row ) {
 392                         $result[] = $row->keyname;
 393                 }
 394
 395                 return $result;
 396         }
 397
 398         protected function isExpired( $exptime ) {
 399                 return $exptime != $this->getMaxDateTime() && wfTimestamp( TS_UNIX, $exptime ) < time();
 400         }
 401
 402         protected function getMaxDateTime() {
 403                 if ( time() > 0x7fffffff ) {
 404                         return $this->getDB()->timestamp( 1 << 62 );
 405                 } else {
 406                         return $this->getDB()->timestamp( 0x7fffffff );
 407                 }
 408         }
 409
 410         protected function garbageCollect() {
 411                 /* Ignore 99% of requests */
 412                 if ( !mt_rand( 0, 100 ) ) {
 413                         $now = time();
 414                         /* Avoid repeating the delete within a few seconds */
 415                         if ( $now > ( $this->lastExpireAll + 1 ) ) {
 416                                 $this->lastExpireAll = $now;
 417                                 $this->expireAll();
 418                         }
 419                 }
 420         }
 421
 422         public function expireAll() {
 423                 $db = $this->getDB();
 424                 $now = $db->timestamp();
 425
 426                 try {
 427                         $db->begin();
 428                         $db->delete( 'objectcache', array( 'exptime < ' . $db->addQuotes( $now ) ), __METHOD__ );
 429                         $db->commit();
 430                 } catch ( DBQueryError $e ) {
 431                         $this->handleWriteError( $e );
 432                 }
 433         }
 434
 435         public function deleteAll() {
 436                 $db = $this->getDB();
 437
 438                 try {
 439                         $db->begin();
 440                         $db->delete( 'objectcache', '*', __METHOD__ );
 441                         $db->commit();
 442                 } catch ( DBQueryError $e ) {
 443                         $this->handleWriteError( $e );
 444                 }
 445         }
 446
 447         /**
 448          * Serialize an object and, if possible, compress the representation.
 449          * On typical message and page data, this can provide a 3X decrease
 450          * in storage requirements.
 451          *
 452          * @param $data mixed
 453          * @return string
 454          */
 455         protected function serialize( &$data ) {
 456                 $serial = serialize( $data );
 457
 458                 if ( function_exists( 'gzdeflate' ) ) {
 459                         return gzdeflate( $serial );
 460                 } else {
 461                         return $serial;
 462                 }
 463         }
 464
 465         /**
 466          * Unserialize and, if necessary, decompress an object.
 467          * @param $serial string
 468          * @return mixed
 469          */
 470         protected function unserialize( $serial ) {
 471                 if ( function_exists( 'gzinflate' ) ) {
 472                         $decomp = @gzinflate( $serial );
 473
 474                         if ( false !== $decomp ) {
 475                                 $serial = $decomp;
 476                         }
 477                 }
 478
 479                 $ret = unserialize( $serial );
 480
 481                 return $ret;
 482         }
 483
 484         /**
 485          * Handle a DBQueryError which occurred during a write operation.
 486          * Ignore errors which are due to a read-only database, rethrow others.
 487          */
 488         protected function handleWriteError( $exception ) {
 489                 $db = $this->getDB();
 490
 491                 if ( !$db->wasReadOnlyError() ) {
 492                         throw $exception;
 493                 }
 494
 495                 try {
 496                         $db->rollback();
 497                 } catch ( DBQueryError $e ) {
 498                 }
 499
 500                 wfDebug( __METHOD__ . ": ignoring query error\n" );
 501                 $db->ignoreErrors( false );
 502         }
 503 }
 504
 505 /**
 506  * Backwards compatibility alias
 507  */
 508 class MediaWikiBagOStuff extends SqlBagOStuff { }
 509
 510 /**
 511  * This is a wrapper for APC's shared memory functions
 512  *
 513  * @ingroup Cache
 514  */
 515 class APCBagOStuff extends BagOStuff {
 516         public function get( $key ) {
 517                 $val = apc_fetch( $key );
 518
 519                 if ( is_string( $val ) ) {
 520                         $val = unserialize( $val );
 521                 }
 522
 523                 return $val;
 524         }
 525
 526         public function set( $key, $value, $exptime = 0 ) {
 527                 apc_store( $key, serialize( $value ), $exptime );
 528
 529                 return true;
 530         }
 531
 532         public function delete( $key, $time = 0 ) {
 533                 apc_delete( $key );
 534
 535                 return true;
 536         }
 537
 538         public function keys() {
 539                 $info = apc_cache_info( 'user' );
 540                 $list = $info['cache_list'];
 541                 $keys = array();
 542
 543                 foreach ( $list as $entry ) {
 544                         $keys[] = $entry['info'];
 545                 }
 546
 547                 return $keys;
 548         }
 549 }
 550
 551 /**
 552  * This is a wrapper for eAccelerator's shared memory functions.
 553  *
 554  * This is basically identical to the deceased Turck MMCache version,
 555  * mostly because eAccelerator is based on Turck MMCache.
 556  *
 557  * @ingroup Cache
 558  */
 559 class eAccelBagOStuff extends BagOStuff {
 560         public function get( $key ) {
 561                 $val = eaccelerator_get( $key );
 562
 563                 if ( is_string( $val ) ) {
 564                         $val = unserialize( $val );
 565                 }
 566
 567                 return $val;
 568         }
 569
 570         public function set( $key, $value, $exptime = 0 ) {
 571                 eaccelerator_put( $key, serialize( $value ), $exptime );
 572
 573                 return true;
 574         }
 575
 576         public function delete( $key, $time = 0 ) {
 577                 eaccelerator_rm( $key );
 578
 579                 return true;
 580         }
 581
 582         public function lock( $key, $waitTimeout = 0 ) {
 583                 eaccelerator_lock( $key );
 584
 585                 return true;
 586         }
 587
 588         public function unlock( $key ) {
 589                 eaccelerator_unlock( $key );
 590
 591                 return true;
 592         }
 593 }
 594
 595 /**
 596  * Wrapper for XCache object caching functions; identical interface
 597  * to the APC wrapper
 598  *
 599  * @ingroup Cache
 600  */
 601 class XCacheBagOStuff extends BagOStuff {
 602         /**
 603          * Get a value from the XCache object cache
 604          *
 605          * @param $key String: cache key
 606          * @return mixed
 607          */
 608         public function get( $key ) {
 609                 $val = xcache_get( $key );
 610
 611                 if ( is_string( $val ) ) {
 612                         $val = unserialize( $val );
 613                 }
 614
 615                 return $val;
 616         }
 617
 618         /**
 619          * Store a value in the XCache object cache
 620          *
 621          * @param $key String: cache key
 622          * @param $value Mixed: object to store
 623          * @param $expire Int: expiration time
 624          * @return bool
 625          */
 626         public function set( $key, $value, $expire = 0 ) {
 627                 xcache_set( $key, serialize( $value ), $expire );
 628
 629                 return true;
 630         }
 631
 632         /**
 633          * Remove a value from the XCache object cache
 634          *
 635          * @param $key String: cache key
 636          * @param $time Int: not used in this implementation
 637          * @return bool
 638          */
 639         public function delete( $key, $time = 0 ) {
 640                 xcache_unset( $key );
 641
 642                 return true;
 643         }
 644 }
 645
 646 /**
 647  * Cache that uses DBA as a backend.
 648  * Slow due to the need to constantly open and close the file to avoid holding
 649  * writer locks. Intended for development use only,  as a memcached workalike
 650  * for systems that don't have it.
 651  *
 652  * @ingroup Cache
 653  */
 654 class DBABagOStuff extends BagOStuff {
 655         var $mHandler, $mFile, $mReader, $mWriter, $mDisabled;
 656
 657         public function __construct( $dir = false ) {
 658                 global $wgDBAhandler;
 659
 660                 if ( $dir === false ) {
 661                         global $wgTmpDirectory;
 662                         $dir = $wgTmpDirectory;
 663                 }
 664
 665                 $this->mFile = "$dir/mw-cache-" . wfWikiID();
 666                 $this->mFile .= '.db';
 667                 wfDebug( __CLASS__ . ": using cache file {$this->mFile}\n" );
 668                 $this->mHandler = $wgDBAhandler;
 669         }
 670
 671         /**
 672          * Encode value and expiry for storage
 673          */
 674         function encode( $value, $expiry ) {
 675                 # Convert to absolute time
 676                 $expiry = $this->convertExpiry( $expiry );
 677
 678                 return sprintf( '%010u', intval( $expiry ) ) . ' ' . serialize( $value );
 679         }
 680
 681         /**
 682          * @return list containing value first and expiry second
 683          */
 684         function decode( $blob ) {
 685                 if ( !is_string( $blob ) ) {
 686                         return array( null, 0 );
 687                 } else {
 688                         return array(
 689                                 unserialize( substr( $blob, 11 ) ),
 690                                 intval( substr( $blob, 0, 10 ) )
 691                         );
 692                 }
 693         }
 694
 695         function getReader() {
 696                 if ( file_exists( $this->mFile ) ) {
 697                         $handle = dba_open( $this->mFile, 'rl', $this->mHandler );
 698                 } else {
 699                         $handle = $this->getWriter();
 700                 }
 701
 702                 if ( !$handle ) {
 703                         wfDebug( "Unable to open DBA cache file {$this->mFile}\n" );
 704                 }
 705
 706                 return $handle;
 707         }
 708
 709         function getWriter() {
 710                 $handle = dba_open( $this->mFile, 'cl', $this->mHandler );
 711
 712                 if ( !$handle ) {
 713                         wfDebug( "Unable to open DBA cache file {$this->mFile}\n" );
 714                 }
 715
 716                 return $handle;
 717         }
 718
 719         function get( $key ) {
 720                 wfProfileIn( __METHOD__ );
 721                 wfDebug( __METHOD__ . "($key)\n" );
 722
 723                 $handle = $this->getReader();
 724                 if ( !$handle ) {
 725                         return null;
 726                 }
 727
 728                 $val = dba_fetch( $key, $handle );
 729                 list( $val, $expiry ) = $this->decode( $val );
 730
 731                 # Must close ASAP because locks are held
 732                 dba_close( $handle );
 733
 734                 if ( !is_null( $val ) && $expiry && $expiry < time() ) {
 735                         # Key is expired, delete it
 736                         $handle = $this->getWriter();
 737                         dba_delete( $key, $handle );
 738                         dba_close( $handle );
 739                         wfDebug( __METHOD__ . ": $key expired\n" );
 740                         $val = null;
 741                 }
 742
 743                 wfProfileOut( __METHOD__ );
 744                 return $val;
 745         }
 746
 747         function set( $key, $value, $exptime = 0 ) {
 748                 wfProfileIn( __METHOD__ );
 749                 wfDebug( __METHOD__ . "($key)\n" );
 750
 751                 $blob = $this->encode( $value, $exptime );
 752
 753                 $handle = $this->getWriter();
 754                 if ( !$handle ) {
 755                         return false;
 756                 }
 757
 758                 $ret = dba_replace( $key, $blob, $handle );
 759                 dba_close( $handle );
 760
 761                 wfProfileOut( __METHOD__ );
 762                 return $ret;
 763         }
 764
 765         function delete( $key, $time = 0 ) {
 766                 wfProfileIn( __METHOD__ );
 767                 wfDebug( __METHOD__ . "($key)\n" );
 768
 769                 $handle = $this->getWriter();
 770                 if ( !$handle ) {
 771                         return false;
 772                 }
 773
 774                 $ret = dba_delete( $key, $handle );
 775                 dba_close( $handle );
 776
 777                 wfProfileOut( __METHOD__ );
 778                 return $ret;
 779         }
 780
 781         function add( $key, $value, $exptime = 0 ) {
 782                 wfProfileIn( __METHOD__ );
 783
 784                 $blob = $this->encode( $value, $exptime );
 785
 786                 $handle = $this->getWriter();
 787
 788                 if ( !$handle ) {
 789                         return false;
 790                 }
 791
 792                 $ret = dba_insert( $key, $blob, $handle );
 793
 794                 # Insert failed, check to see if it failed due to an expired key
 795                 if ( !$ret ) {
 796                         list( $value, $expiry ) = $this->decode( dba_fetch( $key, $handle ) );
 797
 798                         if ( $expiry < time() ) {
 799                                 # Yes expired, delete and try again
 800                                 dba_delete( $key, $handle );
 801                                 $ret = dba_insert( $key, $blob, $handle );
 802                                 # This time if it failed then it will be handled by the caller like any other race
 803                         }
 804                 }
 805
 806                 dba_close( $handle );
 807
 808                 wfProfileOut( __METHOD__ );
 809                 return $ret;
 810         }
 811
 812         function keys() {
 813                 $reader = $this->getReader();
 814                 $k1 = dba_firstkey( $reader );
 815
 816                 if ( !$k1 ) {
 817                         return array();
 818                 }
 819
 820                 $result[] = $k1;
 821
 822                 while ( $key = dba_nextkey( $reader ) ) {
 823                         $result[] = $key;
 824                 }
 825
 826                 return $result;
 827         }
 828 }
 829
 830 /**
 831  * Wrapper for WinCache object caching functions; identical interface
 832  * to the APC wrapper
 833  *
 834  * @ingroup Cache
 835  */
 836 class WinCacheBagOStuff extends BagOStuff {
 837
 838         /**
 839          * Get a value from the WinCache object cache
 840          *
 841          * @param $key String: cache key
 842          * @return mixed
 843          */
 844         public function get( $key ) {
 845                 $val = wincache_ucache_get( $key );
 846
 847                 if ( is_string( $val ) ) {
 848                         $val = unserialize( $val );
 849                 }
 850
 851                 return $val;
 852         }
 853
 854         /**
 855          * Store a value in the WinCache object cache
 856          *
 857          * @param $key String: cache key
 858          * @param $value Mixed: object to store
 859          * @param $expire Int: expiration time
 860          * @return bool
 861          */
 862         public function set( $key, $value, $expire = 0 ) {
 863                 wincache_ucache_set( $key, serialize( $value ), $expire );
 864
 865                 return true;
 866         }
 867
 868         /**
 869          * Remove a value from the WinCache object cache
 870          *
 871          * @param $key String: cache key
 872          * @param $time Int: not used in this implementation
 873          * @return bool
 874          */
 875         public function delete( $key, $time = 0 ) {
 876                 wincache_ucache_delete( $key );
 877
 878                 return true;
 879         }
 880
 881         public function keys() {
 882                 $info = wincache_ucache_info();
 883                 $list = $info['ucache_entries'];
 884                 $keys = array();
 885
 886                 foreach ( $list as $entry ) {
 887                         $keys[] = $entry['key_name'];
 888                 }
 889
 890                 return $keys;
 891         }
 892 }