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 to 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                 if ( !isset( $this->db ) ) {
 244                         /* We must keep a separate connection to MySQL in order to avoid deadlocks
 245                          * However, SQLite has an opposite behaviour.
 246                          * @todo Investigate behaviour for other databases
 247                          */
 248                         if ( wfGetDB( DB_MASTER )->getType() == 'sqlite' ) {
 249                                 $this->db = wfGetDB( DB_MASTER );
 250                         } else {
 251                                 $this->lb = wfGetLBFactory()->newMainLB();
 252                                 $this->db = $this->lb->getConnection( DB_MASTER );
 253                                 $this->db->clearFlag( DBO_TRX );
 254                         }
 255                 }
 256
 257                 return $this->db;
 258         }
 259
 260         public function get( $key ) {
 261                 # expire old entries if any
 262                 $this->garbageCollect();
 263                 $db = $this->getDB();
 264                 $row = $db->selectRow( 'objectcache', array( 'value', 'exptime' ),
 265                         array( 'keyname' => $key ), __METHOD__ );
 266
 267                 if ( !$row ) {
 268                         $this->debug( 'get: no matching rows' );
 269                         return false;
 270                 }
 271
 272                 $this->debug( "get: retrieved data; expiry time is " . $row->exptime );
 273
 274                 if ( $this->isExpired( $row->exptime ) ) {
 275                         $this->debug( "get: key has expired, deleting" );
 276                         try {
 277                                 $db->begin();
 278                                 # Put the expiry time in the WHERE condition to avoid deleting a
 279                                 # newly-inserted value
 280                                 $db->delete( 'objectcache',
 281                                         array(
 282                                                 'keyname' => $key,
 283                                                 'exptime' => $row->exptime
 284                                         ), __METHOD__ );
 285                                 $db->commit();
 286                         } catch ( DBQueryError $e ) {
 287                                 $this->handleWriteError( $e );
 288                         }
 289
 290                         return false;
 291                 }
 292
 293                 return $this->unserialize( $db->decodeBlob( $row->value ) );
 294         }
 295
 296         public function set( $key, $value, $exptime = 0 ) {
 297                 $db = $this->getDB();
 298                 $exptime = intval( $exptime );
 299
 300                 if ( $exptime < 0 ) {
 301                         $exptime = 0;
 302                 }
 303
 304                 if ( $exptime == 0 ) {
 305                         $encExpiry = $this->getMaxDateTime();
 306                 } else {
 307                         if ( $exptime < 3.16e8 ) { # ~10 years
 308                                 $exptime += time();
 309                         }
 310
 311                         $encExpiry = $db->timestamp( $exptime );
 312                 }
 313                 try {
 314                         $db->begin();
 315                         // (bug 24425) use a replace if the db supports it instead of
 316                         // delete/insert to avoid clashes with conflicting keynames
 317                         $db->replace( 'objectcache', array( 'keyname' ),
 318                                 array(
 319                                         'keyname' => $key,
 320                                         'value' => $db->encodeBlob( $this->serialize( $value ) ),
 321                                         'exptime' => $encExpiry
 322                                 ), __METHOD__ );
 323                         $db->commit();
 324                 } catch ( DBQueryError $e ) {
 325                         $this->handleWriteError( $e );
 326
 327                         return false;
 328                 }
 329
 330                 return true;
 331         }
 332
 333         public function delete( $key, $time = 0 ) {
 334                 $db = $this->getDB();
 335
 336                 try {
 337                         $db->begin();
 338                         $db->delete( 'objectcache', array( 'keyname' => $key ), __METHOD__ );
 339                         $db->commit();
 340                 } catch ( DBQueryError $e ) {
 341                         $this->handleWriteError( $e );
 342
 343                         return false;
 344                 }
 345
 346                 return true;
 347         }
 348
 349         public function incr( $key, $step = 1 ) {
 350                 $db = $this->getDB();
 351                 $step = intval( $step );
 352
 353                 try {
 354                         $db->begin();
 355                         $row = $db->selectRow( 'objectcache', array( 'value', 'exptime' ),
 356                                 array( 'keyname' => $key ), __METHOD__, array( 'FOR UPDATE' ) );
 357                         if ( $row === false ) {
 358                                 // Missing
 359                                 $db->commit();
 360
 361                                 return null;
 362                         }
 363                         $db->delete( 'objectcache', array( 'keyname' => $key ), __METHOD__ );
 364                         if ( $this->isExpired( $row->exptime ) ) {
 365                                 // Expired, do not reinsert
 366                                 $db->commit();
 367
 368                                 return null;
 369                         }
 370
 371                         $oldValue = intval( $this->unserialize( $db->decodeBlob( $row->value ) ) );
 372                         $newValue = $oldValue + $step;
 373                         $db->insert( 'objectcache',
 374                                 array(
 375                                         'keyname' => $key,
 376                                         'value' => $db->encodeBlob( $this->serialize( $newValue ) ),
 377                                         'exptime' => $row->exptime
 378                                 ), __METHOD__ );
 379                         $db->commit();
 380                 } catch ( DBQueryError $e ) {
 381                         $this->handleWriteError( $e );
 382
 383                         return null;
 384                 }
 385
 386                 return $newValue;
 387         }
 388
 389         public function keys() {
 390                 $db = $this->getDB();
 391                 $res = $db->select( 'objectcache', array( 'keyname' ), false, __METHOD__ );
 392                 $result = array();
 393
 394                 foreach ( $res as $row ) {
 395                         $result[] = $row->keyname;
 396                 }
 397
 398                 return $result;
 399         }
 400
 401         protected function isExpired( $exptime ) {
 402                 return $exptime != $this->getMaxDateTime() && wfTimestamp( TS_UNIX, $exptime ) < time();
 403         }
 404
 405         protected function getMaxDateTime() {
 406                 if ( time() > 0x7fffffff ) {
 407                         return $this->getDB()->timestamp( 1 << 62 );
 408                 } else {
 409                         return $this->getDB()->timestamp( 0x7fffffff );
 410                 }
 411         }
 412
 413         protected function garbageCollect() {
 414                 /* Ignore 99% of requests */
 415                 if ( !mt_rand( 0, 100 ) ) {
 416                         $now = time();
 417                         /* Avoid repeating the delete within a few seconds */
 418                         if ( $now > ( $this->lastExpireAll + 1 ) ) {
 419                                 $this->lastExpireAll = $now;
 420                                 $this->expireAll();
 421                         }
 422                 }
 423         }
 424
 425         public function expireAll() {
 426                 $db = $this->getDB();
 427                 $now = $db->timestamp();
 428
 429                 try {
 430                         $db->begin();
 431                         $db->delete( 'objectcache', array( 'exptime < ' . $db->addQuotes( $now ) ), __METHOD__ );
 432                         $db->commit();
 433                 } catch ( DBQueryError $e ) {
 434                         $this->handleWriteError( $e );
 435                 }
 436         }
 437
 438         public function deleteAll() {
 439                 $db = $this->getDB();
 440
 441                 try {
 442                         $db->begin();
 443                         $db->delete( 'objectcache', '*', __METHOD__ );
 444                         $db->commit();
 445                 } catch ( DBQueryError $e ) {
 446                         $this->handleWriteError( $e );
 447                 }
 448         }
 449
 450         /**
 451          * Serialize an object and, if possible, compress the representation.
 452          * On typical message and page data, this can provide a 3X decrease
 453          * in storage requirements.
 454          *
 455          * @param $data mixed
 456          * @return string
 457          */
 458         protected function serialize( &$data ) {
 459                 $serial = serialize( $data );
 460
 461                 if ( function_exists( 'gzdeflate' ) ) {
 462                         return gzdeflate( $serial );
 463                 } else {
 464                         return $serial;
 465                 }
 466         }
 467
 468         /**
 469          * Unserialize and, if necessary, decompress an object.
 470          * @param $serial string
 471          * @return mixed
 472          */
 473         protected function unserialize( $serial ) {
 474                 if ( function_exists( 'gzinflate' ) ) {
 475                         $decomp = @gzinflate( $serial );
 476
 477                         if ( false !== $decomp ) {
 478                                 $serial = $decomp;
 479                         }
 480                 }
 481
 482                 $ret = unserialize( $serial );
 483
 484                 return $ret;
 485         }
 486
 487         /**
 488          * Handle a DBQueryError which occurred during a write operation.
 489          * Ignore errors which are due to a read-only database, rethrow others.
 490          */
 491         protected function handleWriteError( $exception ) {
 492                 $db = $this->getDB();
 493
 494                 if ( !$db->wasReadOnlyError() ) {
 495                         throw $exception;
 496                 }
 497
 498                 try {
 499                         $db->rollback();
 500                 } catch ( DBQueryError $e ) {
 501                 }
 502
 503                 wfDebug( __METHOD__ . ": ignoring query error\n" );
 504                 $db->ignoreErrors( false );
 505         }
 506 }
 507
 508 /**
 509  * Backwards compatibility alias
 510  */
 511 class MediaWikiBagOStuff extends SqlBagOStuff { }
 512
 513 /**
 514  * This is a wrapper for APC's shared memory functions
 515  *
 516  * @ingroup Cache
 517  */
 518 class APCBagOStuff extends BagOStuff {
 519         public function get( $key ) {
 520                 $val = apc_fetch( $key );
 521
 522                 if ( is_string( $val ) ) {
 523                         $val = unserialize( $val );
 524                 }
 525
 526                 return $val;
 527         }
 528
 529         public function set( $key, $value, $exptime = 0 ) {
 530                 apc_store( $key, serialize( $value ), $exptime );
 531
 532                 return true;
 533         }
 534
 535         public function delete( $key, $time = 0 ) {
 536                 apc_delete( $key );
 537
 538                 return true;
 539         }
 540
 541         public function keys() {
 542                 $info = apc_cache_info( 'user' );
 543                 $list = $info['cache_list'];
 544                 $keys = array();
 545
 546                 foreach ( $list as $entry ) {
 547                         $keys[] = $entry['info'];
 548                 }
 549
 550                 return $keys;
 551         }
 552 }
 553
 554 /**
 555  * This is a wrapper for eAccelerator's shared memory functions.
 556  *
 557  * This is basically identical to the deceased Turck MMCache version,
 558  * mostly because eAccelerator is based on Turck MMCache.
 559  *
 560  * @ingroup Cache
 561  */
 562 class eAccelBagOStuff extends BagOStuff {
 563         public function get( $key ) {
 564                 $val = eaccelerator_get( $key );
 565
 566                 if ( is_string( $val ) ) {
 567                         $val = unserialize( $val );
 568                 }
 569
 570                 return $val;
 571         }
 572
 573         public function set( $key, $value, $exptime = 0 ) {
 574                 eaccelerator_put( $key, serialize( $value ), $exptime );
 575
 576                 return true;
 577         }
 578
 579         public function delete( $key, $time = 0 ) {
 580                 eaccelerator_rm( $key );
 581
 582                 return true;
 583         }
 584
 585         public function lock( $key, $waitTimeout = 0 ) {
 586                 eaccelerator_lock( $key );
 587
 588                 return true;
 589         }
 590
 591         public function unlock( $key ) {
 592                 eaccelerator_unlock( $key );
 593
 594                 return true;
 595         }
 596 }
 597
 598 /**
 599  * Wrapper for XCache object caching functions; identical interface
 600  * to the APC wrapper
 601  *
 602  * @ingroup Cache
 603  */
 604 class XCacheBagOStuff extends BagOStuff {
 605         /**
 606          * Get a value from the XCache object cache
 607          *
 608          * @param $key String: cache key
 609          * @return mixed
 610          */
 611         public function get( $key ) {
 612                 $val = xcache_get( $key );
 613
 614                 if ( is_string( $val ) ) {
 615                         $val = unserialize( $val );
 616                 }
 617
 618                 return $val;
 619         }
 620
 621         /**
 622          * Store a value in the XCache object cache
 623          *
 624          * @param $key String: cache key
 625          * @param $value Mixed: object to store
 626          * @param $expire Int: expiration time
 627          * @return bool
 628          */
 629         public function set( $key, $value, $expire = 0 ) {
 630                 xcache_set( $key, serialize( $value ), $expire );
 631
 632                 return true;
 633         }
 634
 635         /**
 636          * Remove a value from the XCache object cache
 637          *
 638          * @param $key String: cache key
 639          * @param $time Int: not used in this implementation
 640          * @return bool
 641          */
 642         public function delete( $key, $time = 0 ) {
 643                 xcache_unset( $key );
 644
 645                 return true;
 646         }
 647 }
 648
 649 /**
 650  * Cache that uses DBA as a backend.
 651  * Slow due to the need to constantly open and close the file to avoid holding
 652  * writer locks. Intended for development use only,  as a memcached workalike
 653  * for systems that don't have it.
 654  *
 655  * @ingroup Cache
 656  */
 657 class DBABagOStuff extends BagOStuff {
 658         var $mHandler, $mFile, $mReader, $mWriter, $mDisabled;
 659
 660         public function __construct( $dir = false ) {
 661                 global $wgDBAhandler;
 662
 663                 if ( $dir === false ) {
 664                         global $wgTmpDirectory;
 665                         $dir = $wgTmpDirectory;
 666                 }
 667
 668                 $this->mFile = "$dir/mw-cache-" . wfWikiID();
 669                 $this->mFile .= '.db';
 670                 wfDebug( __CLASS__ . ": using cache file {$this->mFile}\n" );
 671                 $this->mHandler = $wgDBAhandler;
 672         }
 673
 674         /**
 675          * Encode value and expiry for storage
 676          */
 677         function encode( $value, $expiry ) {
 678                 # Convert to absolute time
 679                 $expiry = $this->convertExpiry( $expiry );
 680
 681                 return sprintf( '%010u', intval( $expiry ) ) . ' ' . serialize( $value );
 682         }
 683
 684         /**
 685          * @return list containing value first and expiry second
 686          */
 687         function decode( $blob ) {
 688                 if ( !is_string( $blob ) ) {
 689                         return array( null, 0 );
 690                 } else {
 691                         return array(
 692                                 unserialize( substr( $blob, 11 ) ),
 693                                 intval( substr( $blob, 0, 10 ) )
 694                         );
 695                 }
 696         }
 697
 698         function getReader() {
 699                 if ( file_exists( $this->mFile ) ) {
 700                         $handle = dba_open( $this->mFile, 'rl', $this->mHandler );
 701                 } else {
 702                         $handle = $this->getWriter();
 703                 }
 704
 705                 if ( !$handle ) {
 706                         wfDebug( "Unable to open DBA cache file {$this->mFile}\n" );
 707                 }
 708
 709                 return $handle;
 710         }
 711
 712         function getWriter() {
 713                 $handle = dba_open( $this->mFile, 'cl', $this->mHandler );
 714
 715                 if ( !$handle ) {
 716                         wfDebug( "Unable to open DBA cache file {$this->mFile}\n" );
 717                 }
 718
 719                 return $handle;
 720         }
 721
 722         function get( $key ) {
 723                 wfProfileIn( __METHOD__ );
 724                 wfDebug( __METHOD__ . "($key)\n" );
 725
 726                 $handle = $this->getReader();
 727                 if ( !$handle ) {
 728                         return null;
 729                 }
 730
 731                 $val = dba_fetch( $key, $handle );
 732                 list( $val, $expiry ) = $this->decode( $val );
 733
 734                 # Must close ASAP because locks are held
 735                 dba_close( $handle );
 736
 737                 if ( !is_null( $val ) && $expiry && $expiry < time() ) {
 738                         # Key is expired, delete it
 739                         $handle = $this->getWriter();
 740                         dba_delete( $key, $handle );
 741                         dba_close( $handle );
 742                         wfDebug( __METHOD__ . ": $key expired\n" );
 743                         $val = null;
 744                 }
 745
 746                 wfProfileOut( __METHOD__ );
 747                 return $val;
 748         }
 749
 750         function set( $key, $value, $exptime = 0 ) {
 751                 wfProfileIn( __METHOD__ );
 752                 wfDebug( __METHOD__ . "($key)\n" );
 753
 754                 $blob = $this->encode( $value, $exptime );
 755
 756                 $handle = $this->getWriter();
 757                 if ( !$handle ) {
 758                         return false;
 759                 }
 760
 761                 $ret = dba_replace( $key, $blob, $handle );
 762                 dba_close( $handle );
 763
 764                 wfProfileOut( __METHOD__ );
 765                 return $ret;
 766         }
 767
 768         function delete( $key, $time = 0 ) {
 769                 wfProfileIn( __METHOD__ );
 770                 wfDebug( __METHOD__ . "($key)\n" );
 771
 772                 $handle = $this->getWriter();
 773                 if ( !$handle ) {
 774                         return false;
 775                 }
 776
 777                 $ret = dba_delete( $key, $handle );
 778                 dba_close( $handle );
 779
 780                 wfProfileOut( __METHOD__ );
 781                 return $ret;
 782         }
 783
 784         function add( $key, $value, $exptime = 0 ) {
 785                 wfProfileIn( __METHOD__ );
 786
 787                 $blob = $this->encode( $value, $exptime );
 788
 789                 $handle = $this->getWriter();
 790
 791                 if ( !$handle ) {
 792                         return false;
 793                 }
 794
 795                 $ret = dba_insert( $key, $blob, $handle );
 796
 797                 # Insert failed, check to see if it failed due to an expired key
 798                 if ( !$ret ) {
 799                         list( $value, $expiry ) = $this->decode( dba_fetch( $key, $handle ) );
 800
 801                         if ( $expiry < time() ) {
 802                                 # Yes expired, delete and try again
 803                                 dba_delete( $key, $handle );
 804                                 $ret = dba_insert( $key, $blob, $handle );
 805                                 # This time if it failed then it will be handled by the caller like any other race
 806                         }
 807                 }
 808
 809                 dba_close( $handle );
 810
 811                 wfProfileOut( __METHOD__ );
 812                 return $ret;
 813         }
 814
 815         function keys() {
 816                 $reader = $this->getReader();
 817                 $k1 = dba_firstkey( $reader );
 818
 819                 if ( !$k1 ) {
 820                         return array();
 821                 }
 822
 823                 $result[] = $k1;
 824
 825                 while ( $key = dba_nextkey( $reader ) ) {
 826                         $result[] = $key;
 827                 }
 828
 829                 return $result;
 830         }
 831 }
 832
 833 /**
 834  * Wrapper for WinCache object caching functions; identical interface
 835  * to the APC wrapper
 836  *
 837  * @ingroup Cache
 838  */
 839 class WinCacheBagOStuff extends BagOStuff {
 840
 841         /**
 842          * Get a value from the WinCache object cache
 843          *
 844          * @param $key String: cache key
 845          * @return mixed
 846          */
 847         public function get( $key ) {
 848                 $val = wincache_ucache_get( $key );
 849
 850                 if ( is_string( $val ) ) {
 851                         $val = unserialize( $val );
 852                 }
 853
 854                 return $val;
 855         }
 856
 857         /**
 858          * Store a value in the WinCache object cache
 859          *
 860          * @param $key String: cache key
 861          * @param $value Mixed: object to store
 862          * @param $expire Int: expiration time
 863          * @return bool
 864          */
 865         public function set( $key, $value, $expire = 0 ) {
 866                 $result = wincache_ucache_set( $key, serialize( $value ), $expire );
 867
 868                 /* wincache_ucache_set returns an empty array on success if $value
 869                    was an array, bool otherwise */
 870                 return ( is_array( $result ) && $result === array() ) || $result;
 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                 if ( is_null( $list ) ) {
 892                         return array();
 893                 }
 894
 895                 foreach ( $list as $entry ) {
 896                         $keys[] = $entry['key_name'];
 897                 }
 898
 899                 return $keys;
 900         }
 901 }