includes/objectcache/MemcachedClient.php

   1 <?php
   2 /**
   3  * Memcached client for PHP.
   4  *
   5  * +---------------------------------------------------------------------------+
   6  * | memcached client, PHP                                                     |
   7  * +---------------------------------------------------------------------------+
   8  * | Copyright (c) 2003 Ryan T. Dean <rtdean@cytherianage.net>                 |
   9  * | All rights reserved.                                                      |
  10  * |                                                                           |
  11  * | Redistribution and use in source and binary forms, with or without        |
  12  * | modification, are permitted provided that the following conditions        |
  13  * | are met:                                                                  |
  14  * |                                                                           |
  15  * | 1. Redistributions of source code must retain the above copyright         |
  16  * |    notice, this list of conditions and the following disclaimer.          |
  17  * | 2. Redistributions in binary form must reproduce the above copyright      |
  18  * |    notice, this list of conditions and the following disclaimer in the    |
  19  * |    documentation and/or other materials provided with the distribution.   |
  20  * |                                                                           |
  21  * | THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR      |
  22  * | IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
  23  * | OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.   |
  24  * | IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,          |
  25  * | INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT  |
  26  * | NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
  27  * | DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY     |
  28  * | THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT       |
  29  * | (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF  |
  30  * | THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.         |
  31  * +---------------------------------------------------------------------------+
  32  * | Author: Ryan T. Dean <rtdean@cytherianage.net>                            |
  33  * | Heavily influenced by the Perl memcached client by Brad Fitzpatrick.      |
  34  * |   Permission granted by Brad Fitzpatrick for relicense of ported Perl     |
  35  * |   client logic under 2-clause BSD license.                                |
  36  * +---------------------------------------------------------------------------+
  37  *
  38  * @file
  39  * $TCAnet$
  40  */
  41
  42 /**
  43  * This is the PHP client for memcached - a distributed memory cache daemon.
  44  * More information is available at http://www.danga.com/memcached/
  45  *
  46  * Usage example:
  47  *
  48  * require_once 'memcached.php';
  49  *
  50  * $mc = new MWMemcached(array(
  51  *              'servers' => array('127.0.0.1:10000',
  52  *                                 array('192.0.0.1:10010', 2),
  53  *                                 '127.0.0.1:10020'),
  54  *              'debug'   => false,
  55  *              'compress_threshold' => 10240,
  56  *              'persistent' => true));
  57  *
  58  * $mc->add( 'key', array( 'some', 'array' ) );
  59  * $mc->replace( 'key', 'some random string' );
  60  * $val = $mc->get( 'key' );
  61  *
  62  * @author  Ryan T. Dean <rtdean@cytherianage.net>
  63  * @version 0.1.2
  64  */
  65
  66 // {{{ requirements
  67 // }}}
  68
  69 // {{{ class MWMemcached
  70 /**
  71  * memcached client class implemented using (p)fsockopen()
  72  *
  73  * @author  Ryan T. Dean <rtdean@cytherianage.net>
  74  * @ingroup Cache
  75  */
  76 class MWMemcached {
  77         // {{{ properties
  78         // {{{ public
  79
  80         // {{{ constants
  81         // {{{ flags
  82
  83         /**
  84          * Flag: indicates data is serialized
  85          */
  86         const SERIALIZED = 1;
  87
  88         /**
  89          * Flag: indicates data is compressed
  90          */
  91         const COMPRESSED = 2;
  92
  93         // }}}
  94
  95         /**
  96          * Minimum savings to store data compressed
  97          */
  98         const COMPRESSION_SAVINGS = 0.20;
  99
 100         // }}}
 101
 102         /**
 103          * Command statistics
 104          *
 105          * @var     array
 106          * @access  public
 107          */
 108         var $stats;
 109
 110         // }}}
 111         // {{{ private
 112
 113         /**
 114          * Cached Sockets that are connected
 115          *
 116          * @var     array
 117          * @access  private
 118          */
 119         var $_cache_sock;
 120
 121         /**
 122          * Current debug status; 0 - none to 9 - profiling
 123          *
 124          * @var     boolean
 125          * @access  private
 126          */
 127         var $_debug;
 128
 129         /**
 130          * Dead hosts, assoc array, 'host'=>'unixtime when ok to check again'
 131          *
 132          * @var     array
 133          * @access  private
 134          */
 135         var $_host_dead;
 136
 137         /**
 138          * Is compression available?
 139          *
 140          * @var     boolean
 141          * @access  private
 142          */
 143         var $_have_zlib;
 144
 145         /**
 146          * Do we want to use compression?
 147          *
 148          * @var     boolean
 149          * @access  private
 150          */
 151         var $_compress_enable;
 152
 153         /**
 154          * At how many bytes should we compress?
 155          *
 156          * @var     integer
 157          * @access  private
 158          */
 159         var $_compress_threshold;
 160
 161         /**
 162          * Are we using persistent links?
 163          *
 164          * @var     boolean
 165          * @access  private
 166          */
 167         var $_persistent;
 168
 169         /**
 170          * If only using one server; contains ip:port to connect to
 171          *
 172          * @var     string
 173          * @access  private
 174          */
 175         var $_single_sock;
 176
 177         /**
 178          * Array containing ip:port or array(ip:port, weight)
 179          *
 180          * @var     array
 181          * @access  private
 182          */
 183         var $_servers;
 184
 185         /**
 186          * Our bit buckets
 187          *
 188          * @var     array
 189          * @access  private
 190          */
 191         var $_buckets;
 192
 193         /**
 194          * Total # of bit buckets we have
 195          *
 196          * @var     integer
 197          * @access  private
 198          */
 199         var $_bucketcount;
 200
 201         /**
 202          * # of total servers we have
 203          *
 204          * @var     integer
 205          * @access  private
 206          */
 207         var $_active;
 208
 209         /**
 210          * Stream timeout in seconds. Applies for example to fread()
 211          *
 212          * @var     integer
 213          * @access  private
 214          */
 215         var $_timeout_seconds;
 216
 217         /**
 218          * Stream timeout in microseconds
 219          *
 220          * @var     integer
 221          * @access  private
 222          */
 223         var $_timeout_microseconds;
 224
 225         /**
 226          * Connect timeout in seconds
 227          */
 228         var $_connect_timeout;
 229
 230         /**
 231          * Number of connection attempts for each server
 232          */
 233         var $_connect_attempts;
 234
 235         // }}}
 236         // }}}
 237         // {{{ methods
 238         // {{{ public functions
 239         // {{{ memcached()
 240
 241         /**
 242          * Memcache initializer
 243          *
 244          * @param array $args Associative array of settings
 245          *
 246          * @return  mixed
 247          */
 248         public function __construct( $args ) {
 249                 $this->set_servers( isset( $args['servers'] ) ? $args['servers'] : array() );
 250                 $this->_debug = isset( $args['debug'] ) ? $args['debug'] : false;
 251                 $this->stats = array();
 252                 $this->_compress_threshold = isset( $args['compress_threshold'] ) ? $args['compress_threshold'] : 0;
 253                 $this->_persistent = isset( $args['persistent'] ) ? $args['persistent'] : false;
 254                 $this->_compress_enable = true;
 255                 $this->_have_zlib = function_exists( 'gzcompress' );
 256
 257                 $this->_cache_sock = array();
 258                 $this->_host_dead = array();
 259
 260                 $this->_timeout_seconds = 0;
 261                 $this->_timeout_microseconds = isset( $args['timeout'] ) ? $args['timeout'] : 500000;
 262
 263                 $this->_connect_timeout = isset( $args['connect_timeout'] ) ? $args['connect_timeout'] : 0.1;
 264                 $this->_connect_attempts = 2;
 265         }
 266
 267         // }}}
 268         // {{{ add()
 269
 270         /**
 271          * Adds a key/value to the memcache server if one isn't already set with
 272          * that key
 273          *
 274          * @param string $key key to set with data
 275          * @param $val Mixed: value to store
 276          * @param $exp Integer: (optional) Expiration time. This can be a number of seconds
 277          * to cache for (up to 30 days inclusive).  Any timespans of 30 days + 1 second or
 278          * longer must be the timestamp of the time at which the mapping should expire. It
 279          * is safe to use timestamps in all cases, regardless of expiration
 280          * eg: strtotime("+3 hour")
 281          *
 282          * @return Boolean
 283          */
 284         public function add( $key, $val, $exp = 0 ) {
 285                 return $this->_set( 'add', $key, $val, $exp );
 286         }
 287
 288         // }}}
 289         // {{{ decr()
 290
 291         /**
 292          * Decrease a value stored on the memcache server
 293          *
 294          * @param string $key key to decrease
 295          * @param $amt Integer: (optional) amount to decrease
 296          *
 297          * @return Mixed: FALSE on failure, value on success
 298          */
 299         public function decr( $key, $amt = 1 ) {
 300                 return $this->_incrdecr( 'decr', $key, $amt );
 301         }
 302
 303         // }}}
 304         // {{{ delete()
 305
 306         /**
 307          * Deletes a key from the server, optionally after $time
 308          *
 309          * @param string $key key to delete
 310          * @param $time Integer: (optional) how long to wait before deleting
 311          *
 312          * @return Boolean: TRUE on success, FALSE on failure
 313          */
 314         public function delete( $key, $time = 0 ) {
 315                 if ( !$this->_active ) {
 316                         return false;
 317                 }
 318
 319                 $sock = $this->get_sock( $key );
 320                 if ( !is_resource( $sock ) ) {
 321                         return false;
 322                 }
 323
 324                 $key = is_array( $key ) ? $key[1] : $key;
 325
 326                 if ( isset( $this->stats['delete'] ) ) {
 327                         $this->stats['delete']++;
 328                 } else {
 329                         $this->stats['delete'] = 1;
 330                 }
 331                 $cmd = "delete $key $time\r\n";
 332                 if ( !$this->_fwrite( $sock, $cmd ) ) {
 333                         return false;
 334                 }
 335                 $res = $this->_fgets( $sock );
 336
 337                 if ( $this->_debug ) {
 338                         $this->_debugprint( sprintf( "MemCache: delete %s (%s)\n", $key, $res ) );
 339                 }
 340
 341                 if ( $res == "DELETED" || $res == "NOT_FOUND" ) {
 342                         return true;
 343                 }
 344
 345                 return false;
 346         }
 347
 348         /**
 349          * @param $key
 350          * @param $timeout int
 351          * @return bool
 352          */
 353         public function lock( $key, $timeout = 0 ) {
 354                 /* stub */
 355                 return true;
 356         }
 357
 358         /**
 359          * @param $key
 360          * @return bool
 361          */
 362         public function unlock( $key ) {
 363                 /* stub */
 364                 return true;
 365         }
 366
 367         // }}}
 368         // {{{ disconnect_all()
 369
 370         /**
 371          * Disconnects all connected sockets
 372          */
 373         public function disconnect_all() {
 374                 foreach ( $this->_cache_sock as $sock ) {
 375                         fclose( $sock );
 376                 }
 377
 378                 $this->_cache_sock = array();
 379         }
 380
 381         // }}}
 382         // {{{ enable_compress()
 383
 384         /**
 385          * Enable / Disable compression
 386          *
 387          * @param $enable Boolean: TRUE to enable, FALSE to disable
 388          */
 389         public function enable_compress( $enable ) {
 390                 $this->_compress_enable = $enable;
 391         }
 392
 393         // }}}
 394         // {{{ forget_dead_hosts()
 395
 396         /**
 397          * Forget about all of the dead hosts
 398          */
 399         public function forget_dead_hosts() {
 400                 $this->_host_dead = array();
 401         }
 402
 403         // }}}
 404         // {{{ get()
 405
 406         /**
 407          * Retrieves the value associated with the key from the memcache server
 408          *
 409          * @param array|string $key key to retrieve
 410          * @param $casToken[optional] Float
 411          *
 412          * @return Mixed
 413          */
 414         public function get( $key, &$casToken = null ) {
 415                 wfProfileIn( __METHOD__ );
 416
 417                 if ( $this->_debug ) {
 418                         $this->_debugprint( "get($key)\n" );
 419                 }
 420
 421                 if ( !$this->_active ) {
 422                         wfProfileOut( __METHOD__ );
 423                         return false;
 424                 }
 425
 426                 $sock = $this->get_sock( $key );
 427
 428                 if ( !is_resource( $sock ) ) {
 429                         wfProfileOut( __METHOD__ );
 430                         return false;
 431                 }
 432
 433                 $key = is_array( $key ) ? $key[1] : $key;
 434                 if ( isset( $this->stats['get'] ) ) {
 435                         $this->stats['get']++;
 436                 } else {
 437                         $this->stats['get'] = 1;
 438                 }
 439
 440                 $cmd = "gets $key\r\n";
 441                 if ( !$this->_fwrite( $sock, $cmd ) ) {
 442                         wfProfileOut( __METHOD__ );
 443                         return false;
 444                 }
 445
 446                 $val = array();
 447                 $this->_load_items( $sock, $val, $casToken );
 448
 449                 if ( $this->_debug ) {
 450                         foreach ( $val as $k => $v ) {
 451                                 $this->_debugprint( sprintf( "MemCache: sock %s got %s\n", serialize( $sock ), $k ) );
 452                         }
 453                 }
 454
 455                 $value = false;
 456                 if ( isset( $val[$key] ) ) {
 457                         $value = $val[$key];
 458                 }
 459                 wfProfileOut( __METHOD__ );
 460                 return $value;
 461         }
 462
 463         // }}}
 464         // {{{ get_multi()
 465
 466         /**
 467          * Get multiple keys from the server(s)
 468          *
 469          * @param array $keys keys to retrieve
 470          *
 471          * @return Array
 472          */
 473         public function get_multi( $keys ) {
 474                 if ( !$this->_active ) {
 475                         return false;
 476                 }
 477
 478                 if ( isset( $this->stats['get_multi'] ) ) {
 479                         $this->stats['get_multi']++;
 480                 } else {
 481                         $this->stats['get_multi'] = 1;
 482                 }
 483                 $sock_keys = array();
 484                 $socks = array();
 485                 foreach ( $keys as $key ) {
 486                         $sock = $this->get_sock( $key );
 487                         if ( !is_resource( $sock ) ) {
 488                                 continue;
 489                         }
 490                         $key = is_array( $key ) ? $key[1] : $key;
 491                         if ( !isset( $sock_keys[$sock] ) ) {
 492                                 $sock_keys[intval( $sock )] = array();
 493                                 $socks[] = $sock;
 494                         }
 495                         $sock_keys[intval( $sock )][] = $key;
 496                 }
 497
 498                 $gather = array();
 499                 // Send out the requests
 500                 foreach ( $socks as $sock ) {
 501                         $cmd = 'gets';
 502                         foreach ( $sock_keys[intval( $sock )] as $key ) {
 503                                 $cmd .= ' ' . $key;
 504                         }
 505                         $cmd .= "\r\n";
 506
 507                         if ( $this->_fwrite( $sock, $cmd ) ) {
 508                                 $gather[] = $sock;
 509                         }
 510                 }
 511
 512                 // Parse responses
 513                 $val = array();
 514                 foreach ( $gather as $sock ) {
 515                         $this->_load_items( $sock, $val, $casToken );
 516                 }
 517
 518                 if ( $this->_debug ) {
 519                         foreach ( $val as $k => $v ) {
 520                                 $this->_debugprint( sprintf( "MemCache: got %s\n", $k ) );
 521                         }
 522                 }
 523
 524                 return $val;
 525         }
 526
 527         // }}}
 528         // {{{ incr()
 529
 530         /**
 531          * Increments $key (optionally) by $amt
 532          *
 533          * @param string $key key to increment
 534          * @param $amt Integer: (optional) amount to increment
 535          *
 536          * @return Integer: null if the key does not exist yet (this does NOT
 537          * create new mappings if the key does not exist). If the key does
 538          * exist, this returns the new value for that key.
 539          */
 540         public function incr( $key, $amt = 1 ) {
 541                 return $this->_incrdecr( 'incr', $key, $amt );
 542         }
 543
 544         // }}}
 545         // {{{ replace()
 546
 547         /**
 548          * Overwrites an existing value for key; only works if key is already set
 549          *
 550          * @param string $key key to set value as
 551          * @param $value Mixed: value to store
 552          * @param $exp Integer: (optional) Expiration time. This can be a number of seconds
 553          * to cache for (up to 30 days inclusive).  Any timespans of 30 days + 1 second or
 554          * longer must be the timestamp of the time at which the mapping should expire. It
 555          * is safe to use timestamps in all cases, regardless of exipration
 556          * eg: strtotime("+3 hour")
 557          *
 558          * @return Boolean
 559          */
 560         public function replace( $key, $value, $exp = 0 ) {
 561                 return $this->_set( 'replace', $key, $value, $exp );
 562         }
 563
 564         // }}}
 565         // {{{ run_command()
 566
 567         /**
 568          * Passes through $cmd to the memcache server connected by $sock; returns
 569          * output as an array (null array if no output)
 570          *
 571          * @param $sock Resource: socket to send command on
 572          * @param string $cmd command to run
 573          *
 574          * @return Array: output array
 575          */
 576         public function run_command( $sock, $cmd ) {
 577                 if ( !is_resource( $sock ) ) {
 578                         return array();
 579                 }
 580
 581                 if ( !$this->_fwrite( $sock, $cmd ) ) {
 582                         return array();
 583                 }
 584
 585                 $ret = array();
 586                 while ( true ) {
 587                         $res = $this->_fgets( $sock );
 588                         $ret[] = $res;
 589                         if ( preg_match( '/^END/', $res ) ) {
 590                                 break;
 591                         }
 592                         if ( strlen( $res ) == 0 ) {
 593                                 break;
 594                         }
 595                 }
 596                 return $ret;
 597         }
 598
 599         // }}}
 600         // {{{ set()
 601
 602         /**
 603          * Unconditionally sets a key to a given value in the memcache.  Returns true
 604          * if set successfully.
 605          *
 606          * @param string $key key to set value as
 607          * @param $value Mixed: value to set
 608          * @param $exp Integer: (optional) Expiration time. This can be a number of seconds
 609          * to cache for (up to 30 days inclusive).  Any timespans of 30 days + 1 second or
 610          * longer must be the timestamp of the time at which the mapping should expire. It
 611          * is safe to use timestamps in all cases, regardless of exipration
 612          * eg: strtotime("+3 hour")
 613          *
 614          * @return Boolean: TRUE on success
 615          */
 616         public function set( $key, $value, $exp = 0 ) {
 617                 return $this->_set( 'set', $key, $value, $exp );
 618         }
 619
 620         // }}}
 621         // {{{ cas()
 622
 623         /**
 624          * Sets a key to a given value in the memcache if the current value still corresponds
 625          * to a known, given value.  Returns true if set successfully.
 626          *
 627          * @param $casToken Float: current known value
 628          * @param string $key key to set value as
 629          * @param $value Mixed: value to set
 630          * @param $exp Integer: (optional) Expiration time. This can be a number of seconds
 631          * to cache for (up to 30 days inclusive).  Any timespans of 30 days + 1 second or
 632          * longer must be the timestamp of the time at which the mapping should expire. It
 633          * is safe to use timestamps in all cases, regardless of exipration
 634          * eg: strtotime("+3 hour")
 635          *
 636          * @return Boolean: TRUE on success
 637          */
 638         public function cas( $casToken, $key, $value, $exp = 0 ) {
 639                 return $this->_set( 'cas', $key, $value, $exp, $casToken );
 640         }
 641
 642         // }}}
 643         // {{{ set_compress_threshold()
 644
 645         /**
 646          * Sets the compression threshold
 647          *
 648          * @param $thresh Integer: threshold to compress if larger than
 649          */
 650         public function set_compress_threshold( $thresh ) {
 651                 $this->_compress_threshold = $thresh;
 652         }
 653
 654         // }}}
 655         // {{{ set_debug()
 656
 657         /**
 658          * Sets the debug flag
 659          *
 660          * @param $dbg Boolean: TRUE for debugging, FALSE otherwise
 661          *
 662          * @see     MWMemcached::__construct
 663          */
 664         public function set_debug( $dbg ) {
 665                 $this->_debug = $dbg;
 666         }
 667
 668         // }}}
 669         // {{{ set_servers()
 670
 671         /**
 672          * Sets the server list to distribute key gets and puts between
 673          *
 674          * @param array $list of servers to connect to
 675          *
 676          * @see     MWMemcached::__construct()
 677          */
 678         public function set_servers( $list ) {
 679                 $this->_servers = $list;
 680                 $this->_active = count( $list );
 681                 $this->_buckets = null;
 682                 $this->_bucketcount = 0;
 683
 684                 $this->_single_sock = null;
 685                 if ( $this->_active == 1 ) {
 686                         $this->_single_sock = $this->_servers[0];
 687                 }
 688         }
 689
 690         /**
 691          * Sets the timeout for new connections
 692          *
 693          * @param $seconds Integer: number of seconds
 694          * @param $microseconds Integer: number of microseconds
 695          */
 696         public function set_timeout( $seconds, $microseconds ) {
 697                 $this->_timeout_seconds = $seconds;
 698                 $this->_timeout_microseconds = $microseconds;
 699         }
 700
 701         // }}}
 702         // }}}
 703         // {{{ private methods
 704         // {{{ _close_sock()
 705
 706         /**
 707          * Close the specified socket
 708          *
 709          * @param string $sock socket to close
 710          *
 711          * @access  private
 712          */
 713         function _close_sock( $sock ) {
 714                 $host = array_search( $sock, $this->_cache_sock );
 715                 fclose( $this->_cache_sock[$host] );
 716                 unset( $this->_cache_sock[$host] );
 717         }
 718
 719         // }}}
 720         // {{{ _connect_sock()
 721
 722         /**
 723          * Connects $sock to $host, timing out after $timeout
 724          *
 725          * @param $sock Integer: socket to connect
 726          * @param string $host Host:IP to connect to
 727          *
 728          * @return  boolean
 729          * @access  private
 730          */
 731         function _connect_sock( &$sock, $host ) {
 732                 list( $ip, $port ) = explode( ':', $host );
 733                 $sock = false;
 734                 $timeout = $this->_connect_timeout;
 735                 $errno = $errstr = null;
 736                 for ( $i = 0; !$sock && $i < $this->_connect_attempts; $i++ ) {
 737                         wfSuppressWarnings();
 738                         if ( $this->_persistent == 1 ) {
 739                                 $sock = pfsockopen( $ip, $port, $errno, $errstr, $timeout );
 740                         } else {
 741                                 $sock = fsockopen( $ip, $port, $errno, $errstr, $timeout );
 742                         }
 743                         wfRestoreWarnings();
 744                 }
 745                 if ( !$sock ) {
 746                         $this->_error_log( "Error connecting to $host: $errstr\n" );
 747                         $this->_dead_host( $host );
 748                         return false;
 749                 }
 750
 751                 // Initialise timeout
 752                 stream_set_timeout( $sock, $this->_timeout_seconds, $this->_timeout_microseconds );
 753
 754                 // If the connection was persistent, flush the read buffer in case there
 755                 // was a previous incomplete request on this connection
 756                 if ( $this->_persistent ) {
 757                         $this->_flush_read_buffer( $sock );
 758                 }
 759                 return true;
 760         }
 761
 762         // }}}
 763         // {{{ _dead_sock()
 764
 765         /**
 766          * Marks a host as dead until 30-40 seconds in the future
 767          *
 768          * @param string $sock socket to mark as dead
 769          *
 770          * @access  private
 771          */
 772         function _dead_sock( $sock ) {
 773                 $host = array_search( $sock, $this->_cache_sock );
 774                 $this->_dead_host( $host );
 775         }
 776
 777         /**
 778          * @param $host
 779          */
 780         function _dead_host( $host ) {
 781                 $parts = explode( ':', $host );
 782                 $ip = $parts[0];
 783                 $this->_host_dead[$ip] = time() + 30 + intval( rand( 0, 10 ) );
 784                 $this->_host_dead[$host] = $this->_host_dead[$ip];
 785                 unset( $this->_cache_sock[$host] );
 786         }
 787
 788         // }}}
 789         // {{{ get_sock()
 790
 791         /**
 792          * get_sock
 793          *
 794          * @param string $key key to retrieve value for;
 795          *
 796          * @return Mixed: resource on success, false on failure
 797          * @access private
 798          */
 799         function get_sock( $key ) {
 800                 if ( !$this->_active ) {
 801                         return false;
 802                 }
 803
 804                 if ( $this->_single_sock !== null ) {
 805                         return $this->sock_to_host( $this->_single_sock );
 806                 }
 807
 808                 $hv = is_array( $key ) ? intval( $key[0] ) : $this->_hashfunc( $key );
 809                 if ( $this->_buckets === null ) {
 810                         $bu = array();
 811                         foreach ( $this->_servers as $v ) {
 812                                 if ( is_array( $v ) ) {
 813                                         for ( $i = 0; $i < $v[1]; $i++ ) {
 814                                                 $bu[] = $v[0];
 815                                         }
 816                                 } else {
 817                                         $bu[] = $v;
 818                                 }
 819                         }
 820                         $this->_buckets = $bu;
 821                         $this->_bucketcount = count( $bu );
 822                 }
 823
 824                 $realkey = is_array( $key ) ? $key[1] : $key;
 825                 for ( $tries = 0; $tries < 20; $tries++ ) {
 826                         $host = $this->_buckets[$hv % $this->_bucketcount];
 827                         $sock = $this->sock_to_host( $host );
 828                         if ( is_resource( $sock ) ) {
 829                                 return $sock;
 830                         }
 831                         $hv = $this->_hashfunc( $hv . $realkey );
 832                 }
 833
 834                 return false;
 835         }
 836
 837         // }}}
 838         // {{{ _hashfunc()
 839
 840         /**
 841          * Creates a hash integer based on the $key
 842          *
 843          * @param string $key key to hash
 844          *
 845          * @return Integer: hash value
 846          * @access private
 847          */
 848         function _hashfunc( $key ) {
 849                 # Hash function must be in [0,0x7ffffff]
 850                 # We take the first 31 bits of the MD5 hash, which unlike the hash
 851                 # function used in a previous version of this client, works
 852                 return hexdec( substr( md5( $key ), 0, 8 ) ) & 0x7fffffff;
 853         }
 854
 855         // }}}
 856         // {{{ _incrdecr()
 857
 858         /**
 859          * Perform increment/decriment on $key
 860          *
 861          * @param string $cmd command to perform
 862          * @param string|array $key key to perform it on
 863          * @param $amt Integer amount to adjust
 864          *
 865          * @return Integer: new value of $key
 866          * @access private
 867          */
 868         function _incrdecr( $cmd, $key, $amt = 1 ) {
 869                 if ( !$this->_active ) {
 870                         return null;
 871                 }
 872
 873                 $sock = $this->get_sock( $key );
 874                 if ( !is_resource( $sock ) ) {
 875                         return null;
 876                 }
 877
 878                 $key = is_array( $key ) ? $key[1] : $key;
 879                 if ( isset( $this->stats[$cmd] ) ) {
 880                         $this->stats[$cmd]++;
 881                 } else {
 882                         $this->stats[$cmd] = 1;
 883                 }
 884                 if ( !$this->_fwrite( $sock, "$cmd $key $amt\r\n" ) ) {
 885                         return null;
 886                 }
 887
 888                 $line = $this->_fgets( $sock );
 889                 $match = array();
 890                 if ( !preg_match( '/^(\d+)/', $line, $match ) ) {
 891                         return null;
 892                 }
 893                 return $match[1];
 894         }
 895
 896         // }}}
 897         // {{{ _load_items()
 898
 899         /**
 900          * Load items into $ret from $sock
 901          *
 902          * @param $sock Resource: socket to read from
 903          * @param array $ret returned values
 904          * @param $casToken[optional] Float
 905          * @return boolean True for success, false for failure
 906          *
 907          * @access private
 908          */
 909         function _load_items( $sock, &$ret, &$casToken = null ) {
 910                 $results = array();
 911
 912                 while ( 1 ) {
 913                         $decl = $this->_fgets( $sock );
 914
 915                         if ( $decl === false ) {
 916                                 /*
 917                                  * If nothing can be read, something is wrong because we know exactly when
 918                                  * to stop reading (right after "END") and we return right after that.
 919                                  */
 920                                 return false;
 921                         } elseif ( preg_match( '/^VALUE (\S+) (\d+) (\d+) (\d+)$/', $decl, $match ) ) {
 922                                 /*
 923                                  * Read all data returned. This can be either one or multiple values.
 924                                  * Save all that data (in an array) to be processed later: we'll first
 925                                  * want to continue reading until "END" before doing anything else,
 926                                  * to make sure that we don't leave our client in a state where it's
 927                                  * output is not yet fully read.
 928                                  */
 929                                 $results[] = array(
 930                                         $match[1], // rkey
 931                                         $match[2], // flags
 932                                         $match[3], // len
 933                                         $match[4], // casToken
 934                                         $this->_fread( $sock, $match[3] + 2 ), // data
 935                                 );
 936                         } elseif ( $decl == "END" ) {
 937                                 if ( count( $results ) == 0 ) {
 938                                         return false;
 939                                 }
 940
 941                                 /**
 942                                  * All data has been read, time to process the data and build
 943                                  * meaningful return values.
 944                                  */
 945                                 foreach ( $results as $vars ) {
 946                                         list( $rkey, $flags, $len, $casToken, $data ) = $vars;
 947
 948                                         if ( $data === false || substr( $data, -2 ) !== "\r\n" ) {
 949                                                 $this->_handle_error( $sock,
 950                                                         'line ending missing from data block from $1' );
 951                                                 return false;
 952                                         }
 953                                         $data = substr( $data, 0, -2 );
 954                                         $ret[$rkey] = $data;
 955
 956                                         if ( $this->_have_zlib && $flags & self::COMPRESSED ) {
 957                                                 $ret[$rkey] = gzuncompress( $ret[$rkey] );
 958                                         }
 959
 960                                         /*
 961                                          * This unserialize is the exact reason that we only want to
 962                                          * process data after having read until "END" (instead of doing
 963                                          * this right away): "unserialize" can trigger outside code:
 964                                          * in the event that $ret[$rkey] is a serialized object,
 965                                          * unserializing it will trigger __wakeup() if present. If that
 966                                          * function attempted to read from memcached (while we did not
 967                                          * yet read "END"), these 2 calls would collide.
 968                                          */
 969                                         if ( $flags & self::SERIALIZED ) {
 970                                                 $ret[$rkey] = unserialize( $ret[$rkey] );
 971                                         }
 972                                 }
 973
 974                                 return true;
 975                         } else {
 976                                 $this->_handle_error( $sock, 'Error parsing response from $1' );
 977                                 return false;
 978                         }
 979                 }
 980         }
 981
 982         // }}}
 983         // {{{ _set()
 984
 985         /**
 986          * Performs the requested storage operation to the memcache server
 987          *
 988          * @param string $cmd command to perform
 989          * @param string $key key to act on
 990          * @param $val Mixed: what we need to store
 991          * @param $exp Integer: (optional) Expiration time. This can be a number of seconds
 992          * to cache for (up to 30 days inclusive).  Any timespans of 30 days + 1 second or
 993          * longer must be the timestamp of the time at which the mapping should expire. It
 994          * is safe to use timestamps in all cases, regardless of exipration
 995          * eg: strtotime("+3 hour")
 996          * @param $casToken[optional] Float
 997          *
 998          * @return Boolean
 999          * @access private
1000          */
1001         function _set( $cmd, $key, $val, $exp, $casToken = null ) {
1002                 if ( !$this->_active ) {
1003                         return false;
1004                 }
1005
1006                 $sock = $this->get_sock( $key );
1007                 if ( !is_resource( $sock ) ) {
1008                         return false;
1009                 }
1010
1011                 if ( isset( $this->stats[$cmd] ) ) {
1012                         $this->stats[$cmd]++;
1013                 } else {
1014                         $this->stats[$cmd] = 1;
1015                 }
1016
1017                 $flags = 0;
1018
1019                 if ( !is_scalar( $val ) ) {
1020                         $val = serialize( $val );
1021                         $flags |= self::SERIALIZED;
1022                         if ( $this->_debug ) {
1023                                 $this->_debugprint( sprintf( "client: serializing data as it is not scalar\n" ) );
1024                         }
1025                 }
1026
1027                 $len = strlen( $val );
1028
1029                 if ( $this->_have_zlib && $this->_compress_enable &&
1030                         $this->_compress_threshold && $len >= $this->_compress_threshold )
1031                 {
1032                         $c_val = gzcompress( $val, 9 );
1033                         $c_len = strlen( $c_val );
1034
1035                         if ( $c_len < $len * ( 1 - self::COMPRESSION_SAVINGS ) ) {
1036                                 if ( $this->_debug ) {
1037                                         $this->_debugprint( sprintf( "client: compressing data; was %d bytes is now %d bytes\n", $len, $c_len ) );
1038                                 }
1039                                 $val = $c_val;
1040                                 $len = $c_len;
1041                                 $flags |= self::COMPRESSED;
1042                         }
1043                 }
1044
1045                 $command = "$cmd $key $flags $exp $len";
1046                 if ( $casToken ) {
1047                         $command .= " $casToken";
1048                 }
1049
1050                 if ( !$this->_fwrite( $sock, "$command\r\n$val\r\n" ) ) {
1051                         return false;
1052                 }
1053
1054                 $line = $this->_fgets( $sock );
1055
1056                 if ( $this->_debug ) {
1057                         $this->_debugprint( sprintf( "%s %s (%s)\n", $cmd, $key, $line ) );
1058                 }
1059                 if ( $line == "STORED" ) {
1060                         return true;
1061                 }
1062                 return false;
1063         }
1064
1065         // }}}
1066         // {{{ sock_to_host()
1067
1068         /**
1069          * Returns the socket for the host
1070          *
1071          * @param string $host Host:IP to get socket for
1072          *
1073          * @return Mixed: IO Stream or false
1074          * @access private
1075          */
1076         function sock_to_host( $host ) {
1077                 if ( isset( $this->_cache_sock[$host] ) ) {
1078                         return $this->_cache_sock[$host];
1079                 }
1080
1081                 $sock = null;
1082                 $now = time();
1083                 list( $ip, /* $port */) = explode( ':', $host );
1084                 if ( isset( $this->_host_dead[$host] ) && $this->_host_dead[$host] > $now ||
1085                         isset( $this->_host_dead[$ip] ) && $this->_host_dead[$ip] > $now
1086                 ) {
1087                         return null;
1088                 }
1089
1090                 if ( !$this->_connect_sock( $sock, $host ) ) {
1091                         return null;
1092                 }
1093
1094                 // Do not buffer writes
1095                 stream_set_write_buffer( $sock, 0 );
1096
1097                 $this->_cache_sock[$host] = $sock;
1098
1099                 return $this->_cache_sock[$host];
1100         }
1101
1102         /**
1103          * @param $text string
1104          */
1105         function _debugprint( $text ) {
1106                 wfDebugLog( 'memcached', $text );
1107         }
1108
1109         /**
1110          * @param $text string
1111          */
1112         function _error_log( $text ) {
1113                 wfDebugLog( 'memcached-serious', "Memcached error: $text" );
1114         }
1115
1116         /**
1117          * Write to a stream. If there is an error, mark the socket dead.
1118          *
1119          * @param $sock The socket
1120          * @param $buf The string to write
1121          * @return bool True on success, false on failure
1122          */
1123         function _fwrite( $sock, $buf ) {
1124                 $bytesWritten = 0;
1125                 $bufSize = strlen( $buf );
1126                 while ( $bytesWritten < $bufSize ) {
1127                         $result = fwrite( $sock, $buf );
1128                         $data = stream_get_meta_data( $sock );
1129                         if ( $data['timed_out'] ) {
1130                                 $this->_handle_error( $sock, 'timeout writing to $1' );
1131                                 return false;
1132                         }
1133                         // Contrary to the documentation, fwrite() returns zero on error in PHP 5.3.
1134                         if ( $result === false || $result === 0 ) {
1135                                 $this->_handle_error( $sock, 'error writing to $1' );
1136                                 return false;
1137                         }
1138                         $bytesWritten += $result;
1139                 }
1140
1141                 return true;
1142         }
1143
1144         /**
1145          * Handle an I/O error. Mark the socket dead and log an error.
1146          */
1147         function _handle_error( $sock, $msg ) {
1148                 $peer = stream_socket_get_name( $sock, true /** remote **/ );
1149                 if ( strval( $peer ) === '' ) {
1150                         $peer = array_search( $sock, $this->_cache_sock );
1151                         if ( $peer === false ) {
1152                                 $peer = '[unknown host]';
1153                         }
1154                 }
1155                 $msg = str_replace( '$1', $peer, $msg );
1156                 $this->_error_log( "$msg\n" );
1157                 $this->_dead_sock( $sock );
1158         }
1159
1160         /**
1161          * Read the specified number of bytes from a stream. If there is an error,
1162          * mark the socket dead.
1163          *
1164          * @param $sock The socket
1165          * @param $len The number of bytes to read
1166          * @return The string on success, false on failure.
1167          */
1168         function _fread( $sock, $len ) {
1169                 $buf = '';
1170                 while ( $len > 0 ) {
1171                         $result = fread( $sock, $len );
1172                         $data = stream_get_meta_data( $sock );
1173                         if ( $data['timed_out'] ) {
1174                                 $this->_handle_error( $sock, 'timeout reading from $1' );
1175                                 return false;
1176                         }
1177                         if ( $result === false ) {
1178                                 $this->_handle_error( $sock, 'error reading buffer from $1' );
1179                                 return false;
1180                         }
1181                         if ( $result === '' ) {
1182                                 // This will happen if the remote end of the socket is shut down
1183                                 $this->_handle_error( $sock, 'unexpected end of file reading from $1' );
1184                                 return false;
1185                         }
1186                         $len -= strlen( $result );
1187                         $buf .= $result;
1188                 }
1189                 return $buf;
1190         }
1191
1192         /**
1193          * Read a line from a stream. If there is an error, mark the socket dead.
1194          * The \r\n line ending is stripped from the response.
1195          *
1196          * @param $sock The socket
1197          * @return The string on success, false on failure
1198          */
1199         function _fgets( $sock ) {
1200                 $result = fgets( $sock );
1201                 // fgets() may return a partial line if there is a select timeout after
1202                 // a successful recv(), so we have to check for a timeout even if we
1203                 // got a string response.
1204                 $data = stream_get_meta_data( $sock );
1205                 if ( $data['timed_out'] ) {
1206                         $this->_handle_error( $sock, 'timeout reading line from $1' );
1207                         return false;
1208                 }
1209                 if ( $result === false ) {
1210                         $this->_handle_error( $sock, 'error reading line from $1' );
1211                         return false;
1212                 }
1213                 if ( substr( $result, -2 ) === "\r\n" ) {
1214                         $result = substr( $result, 0, -2 );
1215                 } elseif ( substr( $result, -1 ) === "\n" ) {
1216                         $result = substr( $result, 0, -1 );
1217                 } else {
1218                         $this->_handle_error( $sock, 'line ending missing in response from $1' );
1219                         return false;
1220                 }
1221                 return $result;
1222         }
1223
1224         /**
1225          * Flush the read buffer of a stream
1226          * @param $f Resource
1227          */
1228         function _flush_read_buffer( $f ) {
1229                 if ( !is_resource( $f ) ) {
1230                         return;
1231                 }
1232                 $r = array( $f );
1233                 $w = null;
1234                 $e = null;
1235                 $n = stream_select( $r, $w, $e, 0, 0 );
1236                 while ( $n == 1 && !feof( $f ) ) {
1237                         fread( $f, 1024 );
1238                         $r = array( $f );
1239                         $w = null;
1240                         $e = null;
1241                         $n = stream_select( $r, $w, $e, 0, 0 );
1242                 }
1243         }
1244
1245         // }}}
1246         // }}}
1247         // }}}
1248 }
1249
1250 // }}}
1251
1252 class MemCachedClientforWiki extends MWMemcached {
1253 }