includes/objectcache/MemcachedClient.php

   1 <?php
   2 /**
   3  * +---------------------------------------------------------------------------+
   4  * | memcached client, PHP                                                     |
   5  * +---------------------------------------------------------------------------+
   6  * | Copyright (c) 2003 Ryan T. Dean <rtdean@cytherianage.net>                 |
   7  * | All rights reserved.                                                      |
   8  * |                                                                           |
   9  * | Redistribution and use in source and binary forms, with or without        |
  10  * | modification, are permitted provided that the following conditions        |
  11  * | are met:                                                                  |
  12  * |                                                                           |
  13  * | 1. Redistributions of source code must retain the above copyright         |
  14  * |    notice, this list of conditions and the following disclaimer.          |
  15  * | 2. Redistributions in binary form must reproduce the above copyright      |
  16  * |    notice, this list of conditions and the following disclaimer in the    |
  17  * |    documentation and/or other materials provided with the distribution.   |
  18  * |                                                                           |
  19  * | THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR      |
  20  * | IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
  21  * | OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.   |
  22  * | IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,          |
  23  * | INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT  |
  24  * | NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
  25  * | DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY     |
  26  * | THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT       |
  27  * | (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF  |
  28  * | THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.         |
  29  * +---------------------------------------------------------------------------+
  30  * | Author: Ryan T. Dean <rtdean@cytherianage.net>                            |
  31  * | Heavily influenced by the Perl memcached client by Brad Fitzpatrick.      |
  32  * |   Permission granted by Brad Fitzpatrick for relicense of ported Perl     |
  33  * |   client logic under 2-clause BSD license.                                |
  34  * +---------------------------------------------------------------------------+
  35  *
  36  * @file
  37  * $TCAnet$
  38  */
  39
  40 /**
  41  * This is the PHP client for memcached - a distributed memory cache daemon.
  42  * More information is available at http://www.danga.com/memcached/
  43  *
  44  * Usage example:
  45  *
  46  * require_once 'memcached.php';
  47  *
  48  * $mc = new MWMemcached(array(
  49  *              'servers' => array('127.0.0.1:10000',
  50  *                                 array('192.0.0.1:10010', 2),
  51  *                                 '127.0.0.1:10020'),
  52  *              'debug'   => false,
  53  *              'compress_threshold' => 10240,
  54  *              'persistent' => true));
  55  *
  56  * $mc->add('key', array('some', 'array'));
  57  * $mc->replace('key', 'some random string');
  58  * $val = $mc->get('key');
  59  *
  60  * @author  Ryan T. Dean <rtdean@cytherianage.net>
  61  * @version 0.1.2
  62  */
  63
  64 // {{{ requirements
  65 // }}}
  66
  67 // {{{ class MWMemcached
  68 /**
  69  * memcached client class implemented using (p)fsockopen()
  70  *
  71  * @author  Ryan T. Dean <rtdean@cytherianage.net>
  72  * @ingroup Cache
  73  */
  74 class MWMemcached {
  75         // {{{ properties
  76         // {{{ public
  77
  78         // {{{ constants
  79         // {{{ flags
  80
  81         /**
  82          * Flag: indicates data is serialized
  83          */
  84         const SERIALIZED = 1;
  85
  86         /**
  87          * Flag: indicates data is compressed
  88          */
  89         const COMPRESSED = 2;
  90
  91         // }}}
  92
  93         /**
  94          * Minimum savings to store data compressed
  95          */
  96         const COMPRESSION_SAVINGS = 0.20;
  97
  98         // }}}
  99
 100
 101         /**
 102          * Command statistics
 103          *
 104          * @var     array
 105          * @access  public
 106          */
 107         var $stats;
 108
 109         // }}}
 110         // {{{ private
 111
 112         /**
 113          * Cached Sockets that are connected
 114          *
 115          * @var     array
 116          * @access  private
 117          */
 118         var $_cache_sock;
 119
 120         /**
 121          * Current debug status; 0 - none to 9 - profiling
 122          *
 123          * @var     boolean
 124          * @access  private
 125          */
 126         var $_debug;
 127
 128         /**
 129          * Dead hosts, assoc array, 'host'=>'unixtime when ok to check again'
 130          *
 131          * @var     array
 132          * @access  private
 133          */
 134         var $_host_dead;
 135
 136         /**
 137          * Is compression available?
 138          *
 139          * @var     boolean
 140          * @access  private
 141          */
 142         var $_have_zlib;
 143
 144         /**
 145          * Do we want to use compression?
 146          *
 147          * @var     boolean
 148          * @access  private
 149          */
 150         var $_compress_enable;
 151
 152         /**
 153          * At how many bytes should we compress?
 154          *
 155          * @var     integer
 156          * @access  private
 157          */
 158         var $_compress_threshold;
 159
 160         /**
 161          * Are we using persistent links?
 162          *
 163          * @var     boolean
 164          * @access  private
 165          */
 166         var $_persistent;
 167
 168         /**
 169          * If only using one server; contains ip:port to connect to
 170          *
 171          * @var     string
 172          * @access  private
 173          */
 174         var $_single_sock;
 175
 176         /**
 177          * Array containing ip:port or array(ip:port, weight)
 178          *
 179          * @var     array
 180          * @access  private
 181          */
 182         var $_servers;
 183
 184         /**
 185          * Our bit buckets
 186          *
 187          * @var     array
 188          * @access  private
 189          */
 190         var $_buckets;
 191
 192         /**
 193          * Total # of bit buckets we have
 194          *
 195          * @var     integer
 196          * @access  private
 197          */
 198         var $_bucketcount;
 199
 200         /**
 201          * # of total servers we have
 202          *
 203          * @var     integer
 204          * @access  private
 205          */
 206         var $_active;
 207
 208         /**
 209          * Stream timeout in seconds. Applies for example to fread()
 210          *
 211          * @var     integer
 212          * @access  private
 213          */
 214         var $_timeout_seconds;
 215
 216         /**
 217          * Stream timeout in microseconds
 218          *
 219          * @var     integer
 220          * @access  private
 221          */
 222         var $_timeout_microseconds;
 223
 224         /**
 225          * Connect timeout in seconds
 226          */
 227         var $_connect_timeout;
 228
 229         /**
 230          * Number of connection attempts for each server
 231          */
 232         var $_connect_attempts;
 233
 234         // }}}
 235         // }}}
 236         // {{{ methods
 237         // {{{ public functions
 238         // {{{ memcached()
 239
 240         /**
 241          * Memcache initializer
 242          *
 243          * @param $args Array Associative array of settings
 244          *
 245          * @return  mixed
 246          */
 247         public function __construct( $args ) {
 248                 $this->set_servers( isset( $args['servers'] ) ? $args['servers'] : array() );
 249                 $this->_debug = isset( $args['debug'] ) ? $args['debug'] : false;
 250                 $this->stats = array();
 251                 $this->_compress_threshold = isset( $args['compress_threshold'] ) ? $args['compress_threshold'] : 0;
 252                 $this->_persistent = isset( $args['persistent'] ) ? $args['persistent'] : false;
 253                 $this->_compress_enable = true;
 254                 $this->_have_zlib = function_exists( 'gzcompress' );
 255
 256                 $this->_cache_sock = array();
 257                 $this->_host_dead = array();
 258
 259                 $this->_timeout_seconds = 0;
 260                 $this->_timeout_microseconds = isset( $args['timeout'] ) ? $args['timeout'] : 100000;
 261
 262                 $this->_connect_timeout = isset( $args['connect_timeout'] ) ? $args['connect_timeout'] : 0.1;
 263                 $this->_connect_attempts = 2;
 264         }
 265
 266         // }}}
 267         // {{{ add()
 268
 269         /**
 270          * Adds a key/value to the memcache server if one isn't already set with
 271          * that key
 272          *
 273          * @param $key String: key to set with data
 274          * @param $val Mixed: value to store
 275          * @param $exp Integer: (optional) Expiration time. This can be a number of seconds
 276          * to cache for (up to 30 days inclusive).  Any timespans of 30 days + 1 second or
 277          * longer must be the timestamp of the time at which the mapping should expire. It
 278          * is safe to use timestamps in all cases, regardless of exipration
 279          * eg: strtotime("+3 hour")
 280          *
 281          * @return Boolean
 282          */
 283         public function add( $key, $val, $exp = 0 ) {
 284                 return $this->_set( 'add', $key, $val, $exp );
 285         }
 286
 287         // }}}
 288         // {{{ decr()
 289
 290         /**
 291          * Decrease a value stored on the memcache server
 292          *
 293          * @param $key String: key to decrease
 294          * @param $amt Integer: (optional) amount to decrease
 295          *
 296          * @return Mixed: FALSE on failure, value on success
 297          */
 298         public function decr( $key, $amt = 1 ) {
 299                 return $this->_incrdecr( 'decr', $key, $amt );
 300         }
 301
 302         // }}}
 303         // {{{ delete()
 304
 305         /**
 306          * Deletes a key from the server, optionally after $time
 307          *
 308          * @param $key String: key to delete
 309          * @param $time Integer: (optional) how long to wait before deleting
 310          *
 311          * @return Boolean: TRUE on success, FALSE on failure
 312          */
 313         public function delete( $key, $time = 0 ) {
 314                 if ( !$this->_active ) {
 315                         return false;
 316                 }
 317
 318                 $sock = $this->get_sock( $key );
 319                 if ( !is_resource( $sock ) ) {
 320                         return false;
 321                 }
 322
 323                 $key = is_array( $key ) ? $key[1] : $key;
 324
 325                 if ( isset( $this->stats['delete'] ) ) {
 326                         $this->stats['delete']++;
 327                 } else {
 328                         $this->stats['delete'] = 1;
 329                 }
 330                 $cmd = "delete $key $time\r\n";
 331                 if( !$this->_safe_fwrite( $sock, $cmd, strlen( $cmd ) ) ) {
 332                         $this->_dead_sock( $sock );
 333                         return false;
 334                 }
 335                 $res = trim( fgets( $sock ) );
 336
 337                 if ( $this->_debug ) {
 338                         $this->_debugprint( sprintf( "MemCache: delete %s (%s)\n", $key, $res ) );
 339                 }
 340
 341                 if ( $res == "DELETED" ) {
 342                         return true;
 343                 }
 344                 return false;
 345         }
 346
 347         public function lock( $key, $timeout = 0 ) {
 348                 /* stub */
 349                 return true;
 350         }
 351
 352         public function unlock( $key ) {
 353                 /* stub */
 354                 return true;
 355         }
 356
 357         // }}}
 358         // {{{ disconnect_all()
 359
 360         /**
 361          * Disconnects all connected sockets
 362          */
 363         public function disconnect_all() {
 364                 foreach ( $this->_cache_sock as $sock ) {
 365                         fclose( $sock );
 366                 }
 367
 368                 $this->_cache_sock = array();
 369         }
 370
 371         // }}}
 372         // {{{ enable_compress()
 373
 374         /**
 375          * Enable / Disable compression
 376          *
 377          * @param $enable Boolean: TRUE to enable, FALSE to disable
 378          */
 379         public function enable_compress( $enable ) {
 380                 $this->_compress_enable = $enable;
 381         }
 382
 383         // }}}
 384         // {{{ forget_dead_hosts()
 385
 386         /**
 387          * Forget about all of the dead hosts
 388          */
 389         public function forget_dead_hosts() {
 390                 $this->_host_dead = array();
 391         }
 392
 393         // }}}
 394         // {{{ get()
 395
 396         /**
 397          * Retrieves the value associated with the key from the memcache server
 398          *
 399          * @param $key array|string key to retrieve
 400          *
 401          * @return Mixed
 402          */
 403         public function get( $key ) {
 404                 wfProfileIn( __METHOD__ );
 405
 406                 if ( $this->_debug ) {
 407                         $this->_debugprint( "get($key)\n" );
 408                 }
 409
 410                 if ( !$this->_active ) {
 411                         wfProfileOut( __METHOD__ );
 412                         return false;
 413                 }
 414
 415                 $sock = $this->get_sock( $key );
 416
 417                 if ( !is_resource( $sock ) ) {
 418                         wfProfileOut( __METHOD__ );
 419                         return false;
 420                 }
 421
 422                 $key = is_array( $key ) ? $key[1] : $key;
 423                 if ( isset( $this->stats['get'] ) ) {
 424                         $this->stats['get']++;
 425                 } else {
 426                         $this->stats['get'] = 1;
 427                 }
 428
 429                 $cmd = "get $key\r\n";
 430                 if ( !$this->_safe_fwrite( $sock, $cmd, strlen( $cmd ) ) ) {
 431                         $this->_dead_sock( $sock );
 432                         wfProfileOut( __METHOD__ );
 433                         return false;
 434                 }
 435
 436                 $val = array();
 437                 $this->_load_items( $sock, $val );
 438
 439                 if ( $this->_debug ) {
 440                         foreach ( $val as $k => $v ) {
 441                                 $this->_debugprint( sprintf( "MemCache: sock %s got %s\n", serialize( $sock ), $k ) );
 442                         }
 443                 }
 444
 445                 $value = false;
 446                 if ( isset( $val[$key] ) ) {
 447                         $value = $val[$key];
 448                 }
 449                 wfProfileOut( __METHOD__ );
 450                 return $value;
 451         }
 452
 453         // }}}
 454         // {{{ get_multi()
 455
 456         /**
 457          * Get multiple keys from the server(s)
 458          *
 459          * @param $keys Array: keys to retrieve
 460          *
 461          * @return Array
 462          */
 463         public function get_multi( $keys ) {
 464                 if ( !$this->_active ) {
 465                         return false;
 466                 }
 467
 468                 if ( isset( $this->stats['get_multi'] ) ) {
 469                         $this->stats['get_multi']++;
 470                 } else {
 471                         $this->stats['get_multi'] = 1;
 472                 }
 473                 $sock_keys = array();
 474
 475                 foreach ( $keys as $key ) {
 476                         $sock = $this->get_sock( $key );
 477                         if ( !is_resource( $sock ) ) {
 478                                 continue;
 479                         }
 480                         $key = is_array( $key ) ? $key[1] : $key;
 481                         if ( !isset( $sock_keys[$sock] ) ) {
 482                                 $sock_keys[$sock] = array();
 483                                 $socks[] = $sock;
 484                         }
 485                         $sock_keys[$sock][] = $key;
 486                 }
 487
 488                 // Send out the requests
 489                 foreach ( $socks as $sock ) {
 490                         $cmd = 'get';
 491                         foreach ( $sock_keys[$sock] as $key ) {
 492                                 $cmd .= ' ' . $key;
 493                         }
 494                         $cmd .= "\r\n";
 495
 496                         if ( $this->_safe_fwrite( $sock, $cmd, strlen( $cmd ) ) ) {
 497                                 $gather[] = $sock;
 498                         } else {
 499                                 $this->_dead_sock( $sock );
 500                         }
 501                 }
 502
 503                 // Parse responses
 504                 $val = array();
 505                 foreach ( $gather as $sock ) {
 506                         $this->_load_items( $sock, $val );
 507                 }
 508
 509                 if ( $this->_debug ) {
 510                         foreach ( $val as $k => $v ) {
 511                                 $this->_debugprint( sprintf( "MemCache: got %s\n", $k ) );
 512                         }
 513                 }
 514
 515                 return $val;
 516         }
 517
 518         // }}}
 519         // {{{ incr()
 520
 521         /**
 522          * Increments $key (optionally) by $amt
 523          *
 524          * @param $key String: key to increment
 525          * @param $amt Integer: (optional) amount to increment
 526          *
 527          * @return Integer: null if the key does not exist yet (this does NOT
 528          * create new mappings if the key does not exist). If the key does
 529          * exist, this returns the new value for that key.
 530          */
 531         public function incr( $key, $amt = 1 ) {
 532                 return $this->_incrdecr( 'incr', $key, $amt );
 533         }
 534
 535         // }}}
 536         // {{{ replace()
 537
 538         /**
 539          * Overwrites an existing value for key; only works if key is already set
 540          *
 541          * @param $key String: key to set value as
 542          * @param $value Mixed: value to store
 543          * @param $exp Integer: (optional) Expiration time. This can be a number of seconds
 544          * to cache for (up to 30 days inclusive).  Any timespans of 30 days + 1 second or
 545          * longer must be the timestamp of the time at which the mapping should expire. It
 546          * is safe to use timestamps in all cases, regardless of exipration
 547          * eg: strtotime("+3 hour")
 548          *
 549          * @return Boolean
 550          */
 551         public function replace( $key, $value, $exp = 0 ) {
 552                 return $this->_set( 'replace', $key, $value, $exp );
 553         }
 554
 555         // }}}
 556         // {{{ run_command()
 557
 558         /**
 559          * Passes through $cmd to the memcache server connected by $sock; returns
 560          * output as an array (null array if no output)
 561          *
 562          * NOTE: due to a possible bug in how PHP reads while using fgets(), each
 563          *       line may not be terminated by a \r\n.  More specifically, my testing
 564          *       has shown that, on FreeBSD at least, each line is terminated only
 565          *       with a \n.  This is with the PHP flag auto_detect_line_endings set
 566          *       to falase (the default).
 567          *
 568          * @param $sock Resource: socket to send command on
 569          * @param $cmd String: command to run
 570          *
 571          * @return Array: output array
 572          */
 573         public function run_command( $sock, $cmd ) {
 574                 if ( !is_resource( $sock ) ) {
 575                         return array();
 576                 }
 577
 578                 if ( !$this->_safe_fwrite( $sock, $cmd, strlen( $cmd ) ) ) {
 579                         return array();
 580                 }
 581
 582                 while ( true ) {
 583                         $res = fgets( $sock );
 584                         $ret[] = $res;
 585                         if ( preg_match( '/^END/', $res ) ) {
 586                                 break;
 587                         }
 588                         if ( strlen( $res ) == 0 ) {
 589                                 break;
 590                         }
 591                 }
 592                 return $ret;
 593         }
 594
 595         // }}}
 596         // {{{ set()
 597
 598         /**
 599          * Unconditionally sets a key to a given value in the memcache.  Returns true
 600          * if set successfully.
 601          *
 602          * @param $key String: key to set value as
 603          * @param $value Mixed: value to set
 604          * @param $exp Integer: (optional) Expiration time. This can be a number of seconds
 605          * to cache for (up to 30 days inclusive).  Any timespans of 30 days + 1 second or
 606          * longer must be the timestamp of the time at which the mapping should expire. It
 607          * is safe to use timestamps in all cases, regardless of exipration
 608          * eg: strtotime("+3 hour")
 609          *
 610          * @return Boolean: TRUE on success
 611          */
 612         public function set( $key, $value, $exp = 0 ) {
 613                 return $this->_set( 'set', $key, $value, $exp );
 614         }
 615
 616         // }}}
 617         // {{{ set_compress_threshold()
 618
 619         /**
 620          * Sets the compression threshold
 621          *
 622          * @param $thresh Integer: threshold to compress if larger than
 623          */
 624         public function set_compress_threshold( $thresh ) {
 625                 $this->_compress_threshold = $thresh;
 626         }
 627
 628         // }}}
 629         // {{{ set_debug()
 630
 631         /**
 632          * Sets the debug flag
 633          *
 634          * @param $dbg Boolean: TRUE for debugging, FALSE otherwise
 635          *
 636          * @see     MWMemcached::__construct
 637          */
 638         public function set_debug( $dbg ) {
 639                 $this->_debug = $dbg;
 640         }
 641
 642         // }}}
 643         // {{{ set_servers()
 644
 645         /**
 646          * Sets the server list to distribute key gets and puts between
 647          *
 648          * @param $list Array of servers to connect to
 649          *
 650          * @see     MWMemcached::__construct()
 651          */
 652         public function set_servers( $list ) {
 653                 $this->_servers = $list;
 654                 $this->_active = count( $list );
 655                 $this->_buckets = null;
 656                 $this->_bucketcount = 0;
 657
 658                 $this->_single_sock = null;
 659                 if ( $this->_active == 1 ) {
 660                         $this->_single_sock = $this->_servers[0];
 661                 }
 662         }
 663
 664         /**
 665          * Sets the timeout for new connections
 666          *
 667          * @param $seconds Integer: number of seconds
 668          * @param $microseconds Integer: number of microseconds
 669          */
 670         public function set_timeout( $seconds, $microseconds ) {
 671                 $this->_timeout_seconds = $seconds;
 672                 $this->_timeout_microseconds = $microseconds;
 673         }
 674
 675         // }}}
 676         // }}}
 677         // {{{ private methods
 678         // {{{ _close_sock()
 679
 680         /**
 681          * Close the specified socket
 682          *
 683          * @param $sock String: socket to close
 684          *
 685          * @access  private
 686          */
 687         function _close_sock( $sock ) {
 688                 $host = array_search( $sock, $this->_cache_sock );
 689                 fclose( $this->_cache_sock[$host] );
 690                 unset( $this->_cache_sock[$host] );
 691         }
 692
 693         // }}}
 694         // {{{ _connect_sock()
 695
 696         /**
 697          * Connects $sock to $host, timing out after $timeout
 698          *
 699          * @param $sock Integer: socket to connect
 700          * @param $host String: Host:IP to connect to
 701          *
 702          * @return  boolean
 703          * @access  private
 704          */
 705         function _connect_sock( &$sock, $host ) {
 706                 list( $ip, $port ) = explode( ':', $host );
 707                 $sock = false;
 708                 $timeout = $this->_connect_timeout;
 709                 $errno = $errstr = null;
 710                 for( $i = 0; !$sock && $i < $this->_connect_attempts; $i++ ) {
 711                         wfSuppressWarnings();
 712                         if ( $this->_persistent == 1 ) {
 713                                 $sock = pfsockopen( $ip, $port, $errno, $errstr, $timeout );
 714                         } else {
 715                                 $sock = fsockopen( $ip, $port, $errno, $errstr, $timeout );
 716                         }
 717                         wfRestoreWarnings();
 718                 }
 719                 if ( !$sock ) {
 720                         if ( $this->_debug ) {
 721                                 $this->_debugprint( "Error connecting to $host: $errstr\n" );
 722                         }
 723                         return false;
 724                 }
 725
 726                 // Initialise timeout
 727                 stream_set_timeout( $sock, $this->_timeout_seconds, $this->_timeout_microseconds );
 728
 729                 return true;
 730         }
 731
 732         // }}}
 733         // {{{ _dead_sock()
 734
 735         /**
 736          * Marks a host as dead until 30-40 seconds in the future
 737          *
 738          * @param $sock String: socket to mark as dead
 739          *
 740          * @access  private
 741          */
 742         function _dead_sock( $sock ) {
 743                 $host = array_search( $sock, $this->_cache_sock );
 744                 $this->_dead_host( $host );
 745         }
 746
 747         function _dead_host( $host ) {
 748                 $parts = explode( ':', $host );
 749                 $ip = $parts[0];
 750                 $this->_host_dead[$ip] = time() + 30 + intval( rand( 0, 10 ) );
 751                 $this->_host_dead[$host] = $this->_host_dead[$ip];
 752                 unset( $this->_cache_sock[$host] );
 753         }
 754
 755         // }}}
 756         // {{{ get_sock()
 757
 758         /**
 759          * get_sock
 760          *
 761          * @param $key String: key to retrieve value for;
 762          *
 763          * @return Mixed: resource on success, false on failure
 764          * @access private
 765          */
 766         function get_sock( $key ) {
 767                 if ( !$this->_active ) {
 768                         return false;
 769                 }
 770
 771                 if ( $this->_single_sock !== null ) {
 772                         $this->_flush_read_buffer( $this->_single_sock );
 773                         return $this->sock_to_host( $this->_single_sock );
 774                 }
 775
 776                 $hv = is_array( $key ) ? intval( $key[0] ) : $this->_hashfunc( $key );
 777
 778                 if ( $this->_buckets === null ) {
 779                         foreach ( $this->_servers as $v ) {
 780                                 if ( is_array( $v ) ) {
 781                                         for( $i = 0; $i < $v[1]; $i++ ) {
 782                                                 $bu[] = $v[0];
 783                                         }
 784                                 } else {
 785                                         $bu[] = $v;
 786                                 }
 787                         }
 788                         $this->_buckets = $bu;
 789                         $this->_bucketcount = count( $bu );
 790                 }
 791
 792                 $realkey = is_array( $key ) ? $key[1] : $key;
 793                 for( $tries = 0; $tries < 20; $tries++ ) {
 794                         $host = $this->_buckets[$hv % $this->_bucketcount];
 795                         $sock = $this->sock_to_host( $host );
 796                         if ( is_resource( $sock ) ) {
 797                                 $this->_flush_read_buffer( $sock );
 798                                 return $sock;
 799                         }
 800                         $hv = $this->_hashfunc( $hv . $realkey );
 801                 }
 802
 803                 return false;
 804         }
 805
 806         // }}}
 807         // {{{ _hashfunc()
 808
 809         /**
 810          * Creates a hash integer based on the $key
 811          *
 812          * @param $key String: key to hash
 813          *
 814          * @return Integer: hash value
 815          * @access private
 816          */
 817         function _hashfunc( $key ) {
 818                 # Hash function must on [0,0x7ffffff]
 819                 # We take the first 31 bits of the MD5 hash, which unlike the hash
 820                 # function used in a previous version of this client, works
 821                 return hexdec( substr( md5( $key ), 0, 8 ) ) & 0x7fffffff;
 822         }
 823
 824         // }}}
 825         // {{{ _incrdecr()
 826
 827         /**
 828          * Perform increment/decriment on $key
 829          *
 830          * @param $cmd String command to perform
 831          * @param $key String|array key to perform it on
 832          * @param $amt Integer amount to adjust
 833          *
 834          * @return Integer: new value of $key
 835          * @access private
 836          */
 837         function _incrdecr( $cmd, $key, $amt = 1 ) {
 838                 if ( !$this->_active ) {
 839                         return null;
 840                 }
 841
 842                 $sock = $this->get_sock( $key );
 843                 if ( !is_resource( $sock ) ) {
 844                         return null;
 845                 }
 846
 847                 $key = is_array( $key ) ? $key[1] : $key;
 848                 if ( isset( $this->stats[$cmd] ) ) {
 849                         $this->stats[$cmd]++;
 850                 } else {
 851                         $this->stats[$cmd] = 1;
 852                 }
 853                 if ( !$this->_safe_fwrite( $sock, "$cmd $key $amt\r\n" ) ) {
 854                         return $this->_dead_sock( $sock );
 855                 }
 856
 857                 $line = fgets( $sock );
 858                 $match = array();
 859                 if ( !preg_match( '/^(\d+)/', $line, $match ) ) {
 860                         return null;
 861                 }
 862                 return $match[1];
 863         }
 864
 865         // }}}
 866         // {{{ _load_items()
 867
 868         /**
 869          * Load items into $ret from $sock
 870          *
 871          * @param $sock Resource: socket to read from
 872          * @param $ret Array: returned values
 873          *
 874          * @access private
 875          */
 876         function _load_items( $sock, &$ret ) {
 877                 while ( 1 ) {
 878                         $decl = fgets( $sock );
 879                         if ( $decl == "END\r\n" ) {
 880                                 return true;
 881                         } elseif ( preg_match( '/^VALUE (\S+) (\d+) (\d+)\r\n$/', $decl, $match ) ) {
 882                                 list( $rkey, $flags, $len ) = array( $match[1], $match[2], $match[3] );
 883                                 $bneed = $len + 2;
 884                                 $offset = 0;
 885
 886                                 while ( $bneed > 0 ) {
 887                                         $data = fread( $sock, $bneed );
 888                                         $n = strlen( $data );
 889                                         if ( $n == 0 ) {
 890                                                 break;
 891                                         }
 892                                         $offset += $n;
 893                                         $bneed -= $n;
 894                                         if ( isset( $ret[$rkey] ) ) {
 895                                                 $ret[$rkey] .= $data;
 896                                         } else {
 897                                                 $ret[$rkey] = $data;
 898                                         }
 899                                 }
 900
 901                                 if ( $offset != $len + 2 ) {
 902                                         // Something is borked!
 903                                         if ( $this->_debug ) {
 904                                                 $this->_debugprint( sprintf( "Something is borked!  key %s expecting %d got %d length\n", $rkey, $len + 2, $offset ) );
 905                                         }
 906
 907                                         unset( $ret[$rkey] );
 908                                         $this->_close_sock( $sock );
 909                                         return false;
 910                                 }
 911
 912                                 if ( $this->_have_zlib && $flags & self::COMPRESSED ) {
 913                                         $ret[$rkey] = gzuncompress( $ret[$rkey] );
 914                                 }
 915
 916                                 $ret[$rkey] = rtrim( $ret[$rkey] );
 917
 918                                 if ( $flags & self::SERIALIZED ) {
 919                                         $ret[$rkey] = unserialize( $ret[$rkey] );
 920                                 }
 921
 922                         } else {
 923                                 $this->_debugprint( "Error parsing memcached response\n" );
 924                                 return 0;
 925                         }
 926                 }
 927         }
 928
 929         // }}}
 930         // {{{ _set()
 931
 932         /**
 933          * Performs the requested storage operation to the memcache server
 934          *
 935          * @param $cmd String: command to perform
 936          * @param $key String: key to act on
 937          * @param $val Mixed: what we need to store
 938          * @param $exp Integer: (optional) Expiration time. This can be a number of seconds
 939          * to cache for (up to 30 days inclusive).  Any timespans of 30 days + 1 second or
 940          * longer must be the timestamp of the time at which the mapping should expire. It
 941          * is safe to use timestamps in all cases, regardless of exipration
 942          * eg: strtotime("+3 hour")
 943          *
 944          * @return Boolean
 945          * @access private
 946          */
 947         function _set( $cmd, $key, $val, $exp ) {
 948                 if ( !$this->_active ) {
 949                         return false;
 950                 }
 951
 952                 $sock = $this->get_sock( $key );
 953                 if ( !is_resource( $sock ) ) {
 954                         return false;
 955                 }
 956
 957                 if ( isset( $this->stats[$cmd] ) ) {
 958                         $this->stats[$cmd]++;
 959                 } else {
 960                         $this->stats[$cmd] = 1;
 961                 }
 962
 963                 // TTLs higher than 30 days will be detected as absolute TTLs
 964                 // (UNIX timestamps), and will result in the cache entry being
 965                 // discarded immediately because the expiry is in the past.
 966                 // Clamp expiries >30d at 30d, unless they're >=1e9 in which
 967                 // case they are likely to really be absolute (1e9 = 2011-09-09)
 968                 if ( $exp > 2592000 && $exp < 1000000000 ) {
 969                         $exp = 2592000;
 970                 }
 971
 972                 $flags = 0;
 973
 974                 if ( !is_scalar( $val ) ) {
 975                         $val = serialize( $val );
 976                         $flags |= self::SERIALIZED;
 977                         if ( $this->_debug ) {
 978                                 $this->_debugprint( sprintf( "client: serializing data as it is not scalar\n" ) );
 979                         }
 980                 }
 981
 982                 $len = strlen( $val );
 983
 984                 if ( $this->_have_zlib && $this->_compress_enable &&
 985                          $this->_compress_threshold && $len >= $this->_compress_threshold )
 986                 {
 987                         $c_val = gzcompress( $val, 9 );
 988                         $c_len = strlen( $c_val );
 989
 990                         if ( $c_len < $len * ( 1 - self::COMPRESSION_SAVINGS ) ) {
 991                                 if ( $this->_debug ) {
 992                                         $this->_debugprint( sprintf( "client: compressing data; was %d bytes is now %d bytes\n", $len, $c_len ) );
 993                                 }
 994                                 $val = $c_val;
 995                                 $len = $c_len;
 996                                 $flags |= self::COMPRESSED;
 997                         }
 998                 }
 999                 if ( !$this->_safe_fwrite( $sock, "$cmd $key $flags $exp $len\r\n$val\r\n" ) ) {
1000                         return $this->_dead_sock( $sock );
1001                 }
1002
1003                 $line = trim( fgets( $sock ) );
1004
1005                 if ( $this->_debug ) {
1006                         $this->_debugprint( sprintf( "%s %s (%s)\n", $cmd, $key, $line ) );
1007                 }
1008                 if ( $line == "STORED" ) {
1009                         return true;
1010                 }
1011                 return false;
1012         }
1013
1014         // }}}
1015         // {{{ sock_to_host()
1016
1017         /**
1018          * Returns the socket for the host
1019          *
1020          * @param $host String: Host:IP to get socket for
1021          *
1022          * @return Mixed: IO Stream or false
1023          * @access private
1024          */
1025         function sock_to_host( $host ) {
1026                 if ( isset( $this->_cache_sock[$host] ) ) {
1027                         return $this->_cache_sock[$host];
1028                 }
1029
1030                 $sock = null;
1031                 $now = time();
1032                 list( $ip, /* $port */) = explode( ':', $host );
1033                 if ( isset( $this->_host_dead[$host] ) && $this->_host_dead[$host] > $now ||
1034                         isset( $this->_host_dead[$ip] ) && $this->_host_dead[$ip] > $now
1035                 ) {
1036                         return null;
1037                 }
1038
1039                 if ( !$this->_connect_sock( $sock, $host ) ) {
1040                         return $this->_dead_host( $host );
1041                 }
1042
1043                 // Do not buffer writes
1044                 stream_set_write_buffer( $sock, 0 );
1045
1046                 $this->_cache_sock[$host] = $sock;
1047
1048                 return $this->_cache_sock[$host];
1049         }
1050
1051         function _debugprint( $str ) {
1052                 print( $str );
1053         }
1054
1055         /**
1056          * Write to a stream, timing out after the correct amount of time
1057          *
1058          * @return Boolean: false on failure, true on success
1059          */
1060         /*
1061         function _safe_fwrite( $f, $buf, $len = false ) {
1062                 stream_set_blocking( $f, 0 );
1063
1064                 if ( $len === false ) {
1065                         wfDebug( "Writing " . strlen( $buf ) . " bytes\n" );
1066                         $bytesWritten = fwrite( $f, $buf );
1067                 } else {
1068                         wfDebug( "Writing $len bytes\n" );
1069                         $bytesWritten = fwrite( $f, $buf, $len );
1070                 }
1071                 $n = stream_select( $r = null, $w = array( $f ), $e = null, 10, 0 );
1072                 #   $this->_timeout_seconds, $this->_timeout_microseconds );
1073
1074                 wfDebug( "stream_select returned $n\n" );
1075                 stream_set_blocking( $f, 1 );
1076                 return $n == 1;
1077                 return $bytesWritten;
1078         }*/
1079
1080         /**
1081          * Original behaviour
1082          */
1083         function _safe_fwrite( $f, $buf, $len = false ) {
1084                 if ( $len === false ) {
1085                         $bytesWritten = fwrite( $f, $buf );
1086                 } else {
1087                         $bytesWritten = fwrite( $f, $buf, $len );
1088                 }
1089                 return $bytesWritten;
1090         }
1091
1092         /**
1093          * Flush the read buffer of a stream
1094          */
1095         function _flush_read_buffer( $f ) {
1096                 if ( !is_resource( $f ) ) {
1097                         return;
1098                 }
1099                 $n = stream_select( $r = array( $f ), $w = null, $e = null, 0, 0 );
1100                 while ( $n == 1 && !feof( $f ) ) {
1101                         fread( $f, 1024 );
1102                         $n = stream_select( $r = array( $f ), $w = null, $e = null, 0, 0 );
1103                 }
1104         }
1105
1106         // }}}
1107         // }}}
1108         // }}}
1109 }
1110
1111 // vim: sts=3 sw=3 et
1112
1113 // }}}
1114
1115 class MemCachedClientforWiki extends MWMemcached {
1116         function _debugprint( $text ) {
1117                 wfDebug( "memcached: $text" );
1118         }
1119 }