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         /**
 348          * @param $key
 349          * @param $timeout int
 350          * @return bool
 351          */
 352         public function lock( $key, $timeout = 0 ) {
 353                 /* stub */
 354                 return true;
 355         }
 356
 357         /**
 358          * @param $key
 359          * @return bool
 360          */
 361         public function unlock( $key ) {
 362                 /* stub */
 363                 return true;
 364         }
 365
 366         // }}}
 367         // {{{ disconnect_all()
 368
 369         /**
 370          * Disconnects all connected sockets
 371          */
 372         public function disconnect_all() {
 373                 foreach ( $this->_cache_sock as $sock ) {
 374                         fclose( $sock );
 375                 }
 376
 377                 $this->_cache_sock = array();
 378         }
 379
 380         // }}}
 381         // {{{ enable_compress()
 382
 383         /**
 384          * Enable / Disable compression
 385          *
 386          * @param $enable Boolean: TRUE to enable, FALSE to disable
 387          */
 388         public function enable_compress( $enable ) {
 389                 $this->_compress_enable = $enable;
 390         }
 391
 392         // }}}
 393         // {{{ forget_dead_hosts()
 394
 395         /**
 396          * Forget about all of the dead hosts
 397          */
 398         public function forget_dead_hosts() {
 399                 $this->_host_dead = array();
 400         }
 401
 402         // }}}
 403         // {{{ get()
 404
 405         /**
 406          * Retrieves the value associated with the key from the memcache server
 407          *
 408          * @param $key array|string key to retrieve
 409          *
 410          * @return Mixed
 411          */
 412         public function get( $key ) {
 413                 wfProfileIn( __METHOD__ );
 414
 415                 if ( $this->_debug ) {
 416                         $this->_debugprint( "get($key)\n" );
 417                 }
 418
 419                 if ( !$this->_active ) {
 420                         wfProfileOut( __METHOD__ );
 421                         return false;
 422                 }
 423
 424                 $sock = $this->get_sock( $key );
 425
 426                 if ( !is_resource( $sock ) ) {
 427                         wfProfileOut( __METHOD__ );
 428                         return false;
 429                 }
 430
 431                 $key = is_array( $key ) ? $key[1] : $key;
 432                 if ( isset( $this->stats['get'] ) ) {
 433                         $this->stats['get']++;
 434                 } else {
 435                         $this->stats['get'] = 1;
 436                 }
 437
 438                 $cmd = "get $key\r\n";
 439                 if ( !$this->_safe_fwrite( $sock, $cmd, strlen( $cmd ) ) ) {
 440                         $this->_dead_sock( $sock );
 441                         wfProfileOut( __METHOD__ );
 442                         return false;
 443                 }
 444
 445                 $val = array();
 446                 $this->_load_items( $sock, $val );
 447
 448                 if ( $this->_debug ) {
 449                         foreach ( $val as $k => $v ) {
 450                                 $this->_debugprint( sprintf( "MemCache: sock %s got %s\n", serialize( $sock ), $k ) );
 451                         }
 452                 }
 453
 454                 $value = false;
 455                 if ( isset( $val[$key] ) ) {
 456                         $value = $val[$key];
 457                 }
 458                 wfProfileOut( __METHOD__ );
 459                 return $value;
 460         }
 461
 462         // }}}
 463         // {{{ get_multi()
 464
 465         /**
 466          * Get multiple keys from the server(s)
 467          *
 468          * @param $keys Array: keys to retrieve
 469          *
 470          * @return Array
 471          */
 472         public function get_multi( $keys ) {
 473                 if ( !$this->_active ) {
 474                         return false;
 475                 }
 476
 477                 if ( isset( $this->stats['get_multi'] ) ) {
 478                         $this->stats['get_multi']++;
 479                 } else {
 480                         $this->stats['get_multi'] = 1;
 481                 }
 482                 $sock_keys = array();
 483                 $socks = array();
 484                 foreach ( $keys as $key ) {
 485                         $sock = $this->get_sock( $key );
 486                         if ( !is_resource( $sock ) ) {
 487                                 continue;
 488                         }
 489                         $key = is_array( $key ) ? $key[1] : $key;
 490                         if ( !isset( $sock_keys[$sock] ) ) {
 491                                 $sock_keys[$sock] = array();
 492                                 $socks[] = $sock;
 493                         }
 494                         $sock_keys[$sock][] = $key;
 495                 }
 496
 497                 $gather = array();
 498                 // Send out the requests
 499                 foreach ( $socks as $sock ) {
 500                         $cmd = 'get';
 501                         foreach ( $sock_keys[$sock] as $key ) {
 502                                 $cmd .= ' ' . $key;
 503                         }
 504                         $cmd .= "\r\n";
 505
 506                         if ( $this->_safe_fwrite( $sock, $cmd, strlen( $cmd ) ) ) {
 507                                 $gather[] = $sock;
 508                         } else {
 509                                 $this->_dead_sock( $sock );
 510                         }
 511                 }
 512
 513                 // Parse responses
 514                 $val = array();
 515                 foreach ( $gather as $sock ) {
 516                         $this->_load_items( $sock, $val );
 517                 }
 518
 519                 if ( $this->_debug ) {
 520                         foreach ( $val as $k => $v ) {
 521                                 $this->_debugprint( sprintf( "MemCache: got %s\n", $k ) );
 522                         }
 523                 }
 524
 525                 return $val;
 526         }
 527
 528         // }}}
 529         // {{{ incr()
 530
 531         /**
 532          * Increments $key (optionally) by $amt
 533          *
 534          * @param $key String: key to increment
 535          * @param $amt Integer: (optional) amount to increment
 536          *
 537          * @return Integer: null if the key does not exist yet (this does NOT
 538          * create new mappings if the key does not exist). If the key does
 539          * exist, this returns the new value for that key.
 540          */
 541         public function incr( $key, $amt = 1 ) {
 542                 return $this->_incrdecr( 'incr', $key, $amt );
 543         }
 544
 545         // }}}
 546         // {{{ replace()
 547
 548         /**
 549          * Overwrites an existing value for key; only works if key is already set
 550          *
 551          * @param $key String: key to set value as
 552          * @param $value Mixed: value to store
 553          * @param $exp Integer: (optional) Expiration time. This can be a number of seconds
 554          * to cache for (up to 30 days inclusive).  Any timespans of 30 days + 1 second or
 555          * longer must be the timestamp of the time at which the mapping should expire. It
 556          * is safe to use timestamps in all cases, regardless of exipration
 557          * eg: strtotime("+3 hour")
 558          *
 559          * @return Boolean
 560          */
 561         public function replace( $key, $value, $exp = 0 ) {
 562                 return $this->_set( 'replace', $key, $value, $exp );
 563         }
 564
 565         // }}}
 566         // {{{ run_command()
 567
 568         /**
 569          * Passes through $cmd to the memcache server connected by $sock; returns
 570          * output as an array (null array if no output)
 571          *
 572          * NOTE: due to a possible bug in how PHP reads while using fgets(), each
 573          *       line may not be terminated by a \r\n.  More specifically, my testing
 574          *       has shown that, on FreeBSD at least, each line is terminated only
 575          *       with a \n.  This is with the PHP flag auto_detect_line_endings set
 576          *       to falase (the default).
 577          *
 578          * @param $sock Resource: socket to send command on
 579          * @param $cmd String: command to run
 580          *
 581          * @return Array: output array
 582          */
 583         public function run_command( $sock, $cmd ) {
 584                 if ( !is_resource( $sock ) ) {
 585                         return array();
 586                 }
 587
 588                 if ( !$this->_safe_fwrite( $sock, $cmd, strlen( $cmd ) ) ) {
 589                         return array();
 590                 }
 591
 592                 $ret = array();
 593                 while ( true ) {
 594                         $res = fgets( $sock );
 595                         $ret[] = $res;
 596                         if ( preg_match( '/^END/', $res ) ) {
 597                                 break;
 598                         }
 599                         if ( strlen( $res ) == 0 ) {
 600                                 break;
 601                         }
 602                 }
 603                 return $ret;
 604         }
 605
 606         // }}}
 607         // {{{ set()
 608
 609         /**
 610          * Unconditionally sets a key to a given value in the memcache.  Returns true
 611          * if set successfully.
 612          *
 613          * @param $key String: key to set value as
 614          * @param $value Mixed: value to set
 615          * @param $exp Integer: (optional) Expiration time. This can be a number of seconds
 616          * to cache for (up to 30 days inclusive).  Any timespans of 30 days + 1 second or
 617          * longer must be the timestamp of the time at which the mapping should expire. It
 618          * is safe to use timestamps in all cases, regardless of exipration
 619          * eg: strtotime("+3 hour")
 620          *
 621          * @return Boolean: TRUE on success
 622          */
 623         public function set( $key, $value, $exp = 0 ) {
 624                 return $this->_set( 'set', $key, $value, $exp );
 625         }
 626
 627         // }}}
 628         // {{{ set_compress_threshold()
 629
 630         /**
 631          * Sets the compression threshold
 632          *
 633          * @param $thresh Integer: threshold to compress if larger than
 634          */
 635         public function set_compress_threshold( $thresh ) {
 636                 $this->_compress_threshold = $thresh;
 637         }
 638
 639         // }}}
 640         // {{{ set_debug()
 641
 642         /**
 643          * Sets the debug flag
 644          *
 645          * @param $dbg Boolean: TRUE for debugging, FALSE otherwise
 646          *
 647          * @see     MWMemcached::__construct
 648          */
 649         public function set_debug( $dbg ) {
 650                 $this->_debug = $dbg;
 651         }
 652
 653         // }}}
 654         // {{{ set_servers()
 655
 656         /**
 657          * Sets the server list to distribute key gets and puts between
 658          *
 659          * @param $list Array of servers to connect to
 660          *
 661          * @see     MWMemcached::__construct()
 662          */
 663         public function set_servers( $list ) {
 664                 $this->_servers = $list;
 665                 $this->_active = count( $list );
 666                 $this->_buckets = null;
 667                 $this->_bucketcount = 0;
 668
 669                 $this->_single_sock = null;
 670                 if ( $this->_active == 1 ) {
 671                         $this->_single_sock = $this->_servers[0];
 672                 }
 673         }
 674
 675         /**
 676          * Sets the timeout for new connections
 677          *
 678          * @param $seconds Integer: number of seconds
 679          * @param $microseconds Integer: number of microseconds
 680          */
 681         public function set_timeout( $seconds, $microseconds ) {
 682                 $this->_timeout_seconds = $seconds;
 683                 $this->_timeout_microseconds = $microseconds;
 684         }
 685
 686         // }}}
 687         // }}}
 688         // {{{ private methods
 689         // {{{ _close_sock()
 690
 691         /**
 692          * Close the specified socket
 693          *
 694          * @param $sock String: socket to close
 695          *
 696          * @access  private
 697          */
 698         function _close_sock( $sock ) {
 699                 $host = array_search( $sock, $this->_cache_sock );
 700                 fclose( $this->_cache_sock[$host] );
 701                 unset( $this->_cache_sock[$host] );
 702         }
 703
 704         // }}}
 705         // {{{ _connect_sock()
 706
 707         /**
 708          * Connects $sock to $host, timing out after $timeout
 709          *
 710          * @param $sock Integer: socket to connect
 711          * @param $host String: Host:IP to connect to
 712          *
 713          * @return  boolean
 714          * @access  private
 715          */
 716         function _connect_sock( &$sock, $host ) {
 717                 list( $ip, $port ) = explode( ':', $host );
 718                 $sock = false;
 719                 $timeout = $this->_connect_timeout;
 720                 $errno = $errstr = null;
 721                 for( $i = 0; !$sock && $i < $this->_connect_attempts; $i++ ) {
 722                         wfSuppressWarnings();
 723                         if ( $this->_persistent == 1 ) {
 724                                 $sock = pfsockopen( $ip, $port, $errno, $errstr, $timeout );
 725                         } else {
 726                                 $sock = fsockopen( $ip, $port, $errno, $errstr, $timeout );
 727                         }
 728                         wfRestoreWarnings();
 729                 }
 730                 if ( !$sock ) {
 731                         if ( $this->_debug ) {
 732                                 $this->_debugprint( "Error connecting to $host: $errstr\n" );
 733                         }
 734                         return false;
 735                 }
 736
 737                 // Initialise timeout
 738                 stream_set_timeout( $sock, $this->_timeout_seconds, $this->_timeout_microseconds );
 739
 740                 return true;
 741         }
 742
 743         // }}}
 744         // {{{ _dead_sock()
 745
 746         /**
 747          * Marks a host as dead until 30-40 seconds in the future
 748          *
 749          * @param $sock String: socket to mark as dead
 750          *
 751          * @access  private
 752          */
 753         function _dead_sock( $sock ) {
 754                 $host = array_search( $sock, $this->_cache_sock );
 755                 $this->_dead_host( $host );
 756         }
 757
 758         /**
 759          * @param $host
 760          */
 761         function _dead_host( $host ) {
 762                 $parts = explode( ':', $host );
 763                 $ip = $parts[0];
 764                 $this->_host_dead[$ip] = time() + 30 + intval( rand( 0, 10 ) );
 765                 $this->_host_dead[$host] = $this->_host_dead[$ip];
 766                 unset( $this->_cache_sock[$host] );
 767         }
 768
 769         // }}}
 770         // {{{ get_sock()
 771
 772         /**
 773          * get_sock
 774          *
 775          * @param $key String: key to retrieve value for;
 776          *
 777          * @return Mixed: resource on success, false on failure
 778          * @access private
 779          */
 780         function get_sock( $key ) {
 781                 if ( !$this->_active ) {
 782                         return false;
 783                 }
 784
 785                 if ( $this->_single_sock !== null ) {
 786                         $this->_flush_read_buffer( $this->_single_sock );
 787                         return $this->sock_to_host( $this->_single_sock );
 788                 }
 789
 790                 $hv = is_array( $key ) ? intval( $key[0] ) : $this->_hashfunc( $key );
 791                 if ( $this->_buckets === null ) {
 792                         $bu = array();
 793                         foreach ( $this->_servers as $v ) {
 794                                 if ( is_array( $v ) ) {
 795                                         for( $i = 0; $i < $v[1]; $i++ ) {
 796                                                 $bu[] = $v[0];
 797                                         }
 798                                 } else {
 799                                         $bu[] = $v;
 800                                 }
 801                         }
 802                         $this->_buckets = $bu;
 803                         $this->_bucketcount = count( $bu );
 804                 }
 805
 806                 $realkey = is_array( $key ) ? $key[1] : $key;
 807                 for( $tries = 0; $tries < 20; $tries++ ) {
 808                         $host = $this->_buckets[$hv % $this->_bucketcount];
 809                         $sock = $this->sock_to_host( $host );
 810                         if ( is_resource( $sock ) ) {
 811                                 $this->_flush_read_buffer( $sock );
 812                                 return $sock;
 813                         }
 814                         $hv = $this->_hashfunc( $hv . $realkey );
 815                 }
 816
 817                 return false;
 818         }
 819
 820         // }}}
 821         // {{{ _hashfunc()
 822
 823         /**
 824          * Creates a hash integer based on the $key
 825          *
 826          * @param $key String: key to hash
 827          *
 828          * @return Integer: hash value
 829          * @access private
 830          */
 831         function _hashfunc( $key ) {
 832                 # Hash function must on [0,0x7ffffff]
 833                 # We take the first 31 bits of the MD5 hash, which unlike the hash
 834                 # function used in a previous version of this client, works
 835                 return hexdec( substr( md5( $key ), 0, 8 ) ) & 0x7fffffff;
 836         }
 837
 838         // }}}
 839         // {{{ _incrdecr()
 840
 841         /**
 842          * Perform increment/decriment on $key
 843          *
 844          * @param $cmd String command to perform
 845          * @param $key String|array key to perform it on
 846          * @param $amt Integer amount to adjust
 847          *
 848          * @return Integer: new value of $key
 849          * @access private
 850          */
 851         function _incrdecr( $cmd, $key, $amt = 1 ) {
 852                 if ( !$this->_active ) {
 853                         return null;
 854                 }
 855
 856                 $sock = $this->get_sock( $key );
 857                 if ( !is_resource( $sock ) ) {
 858                         return null;
 859                 }
 860
 861                 $key = is_array( $key ) ? $key[1] : $key;
 862                 if ( isset( $this->stats[$cmd] ) ) {
 863                         $this->stats[$cmd]++;
 864                 } else {
 865                         $this->stats[$cmd] = 1;
 866                 }
 867                 if ( !$this->_safe_fwrite( $sock, "$cmd $key $amt\r\n" ) ) {
 868                         $this->_dead_sock( $sock );
 869                         return null;
 870                 }
 871
 872                 $line = fgets( $sock );
 873                 $match = array();
 874                 if ( !preg_match( '/^(\d+)/', $line, $match ) ) {
 875                         return null;
 876                 }
 877                 return $match[1];
 878         }
 879
 880         // }}}
 881         // {{{ _load_items()
 882
 883         /**
 884          * Load items into $ret from $sock
 885          *
 886          * @param $sock Resource: socket to read from
 887          * @param $ret Array: returned values
 888          *
 889          * @return bool|int
 890          * @access private
 891          */
 892         function _load_items( $sock, &$ret ) {
 893                 while ( 1 ) {
 894                         $decl = fgets( $sock );
 895                         if ( $decl == "END\r\n" ) {
 896                                 return true;
 897                         } elseif ( preg_match( '/^VALUE (\S+) (\d+) (\d+)\r\n$/', $decl, $match ) ) {
 898                                 list( $rkey, $flags, $len ) = array( $match[1], $match[2], $match[3] );
 899                                 $bneed = $len + 2;
 900                                 $offset = 0;
 901
 902                                 while ( $bneed > 0 ) {
 903                                         $data = fread( $sock, $bneed );
 904                                         $n = strlen( $data );
 905                                         if ( $n == 0 ) {
 906                                                 break;
 907                                         }
 908                                         $offset += $n;
 909                                         $bneed -= $n;
 910                                         if ( isset( $ret[$rkey] ) ) {
 911                                                 $ret[$rkey] .= $data;
 912                                         } else {
 913                                                 $ret[$rkey] = $data;
 914                                         }
 915                                 }
 916
 917                                 if ( $offset != $len + 2 ) {
 918                                         // Something is borked!
 919                                         if ( $this->_debug ) {
 920                                                 $this->_debugprint( sprintf( "Something is borked!  key %s expecting %d got %d length\n", $rkey, $len + 2, $offset ) );
 921                                         }
 922
 923                                         unset( $ret[$rkey] );
 924                                         $this->_close_sock( $sock );
 925                                         return false;
 926                                 }
 927
 928                                 if ( $this->_have_zlib && $flags & self::COMPRESSED ) {
 929                                         $ret[$rkey] = gzuncompress( $ret[$rkey] );
 930                                 }
 931
 932                                 $ret[$rkey] = rtrim( $ret[$rkey] );
 933
 934                                 if ( $flags & self::SERIALIZED ) {
 935                                         $ret[$rkey] = unserialize( $ret[$rkey] );
 936                                 }
 937
 938                         } else {
 939                                 $this->_debugprint( "Error parsing memcached response\n" );
 940                                 return 0;
 941                         }
 942                 }
 943         }
 944
 945         // }}}
 946         // {{{ _set()
 947
 948         /**
 949          * Performs the requested storage operation to the memcache server
 950          *
 951          * @param $cmd String: command to perform
 952          * @param $key String: key to act on
 953          * @param $val Mixed: what we need to store
 954          * @param $exp Integer: (optional) Expiration time. This can be a number of seconds
 955          * to cache for (up to 30 days inclusive).  Any timespans of 30 days + 1 second or
 956          * longer must be the timestamp of the time at which the mapping should expire. It
 957          * is safe to use timestamps in all cases, regardless of exipration
 958          * eg: strtotime("+3 hour")
 959          *
 960          * @return Boolean
 961          * @access private
 962          */
 963         function _set( $cmd, $key, $val, $exp ) {
 964                 if ( !$this->_active ) {
 965                         return false;
 966                 }
 967
 968                 $sock = $this->get_sock( $key );
 969                 if ( !is_resource( $sock ) ) {
 970                         return false;
 971                 }
 972
 973                 if ( isset( $this->stats[$cmd] ) ) {
 974                         $this->stats[$cmd]++;
 975                 } else {
 976                         $this->stats[$cmd] = 1;
 977                 }
 978
 979                 // TTLs higher than 30 days will be detected as absolute TTLs
 980                 // (UNIX timestamps), and will result in the cache entry being
 981                 // discarded immediately because the expiry is in the past.
 982                 // Clamp expiries >30d at 30d, unless they're >=1e9 in which
 983                 // case they are likely to really be absolute (1e9 = 2011-09-09)
 984                 if ( $exp > 2592000 && $exp < 1000000000 ) {
 985                         $exp = 2592000;
 986                 }
 987
 988                 $flags = 0;
 989
 990                 if ( !is_scalar( $val ) ) {
 991                         $val = serialize( $val );
 992                         $flags |= self::SERIALIZED;
 993                         if ( $this->_debug ) {
 994                                 $this->_debugprint( sprintf( "client: serializing data as it is not scalar\n" ) );
 995                         }
 996                 }
 997
 998                 $len = strlen( $val );
 999
1000                 if ( $this->_have_zlib && $this->_compress_enable &&
1001                          $this->_compress_threshold && $len >= $this->_compress_threshold )
1002                 {
1003                         $c_val = gzcompress( $val, 9 );
1004                         $c_len = strlen( $c_val );
1005
1006                         if ( $c_len < $len * ( 1 - self::COMPRESSION_SAVINGS ) ) {
1007                                 if ( $this->_debug ) {
1008                                         $this->_debugprint( sprintf( "client: compressing data; was %d bytes is now %d bytes\n", $len, $c_len ) );
1009                                 }
1010                                 $val = $c_val;
1011                                 $len = $c_len;
1012                                 $flags |= self::COMPRESSED;
1013                         }
1014                 }
1015                 if ( !$this->_safe_fwrite( $sock, "$cmd $key $flags $exp $len\r\n$val\r\n" ) ) {
1016                         $this->_dead_sock( $sock );
1017                         return false;
1018                 }
1019
1020                 $line = trim( fgets( $sock ) );
1021
1022                 if ( $this->_debug ) {
1023                         $this->_debugprint( sprintf( "%s %s (%s)\n", $cmd, $key, $line ) );
1024                 }
1025                 if ( $line == "STORED" ) {
1026                         return true;
1027                 }
1028                 return false;
1029         }
1030
1031         // }}}
1032         // {{{ sock_to_host()
1033
1034         /**
1035          * Returns the socket for the host
1036          *
1037          * @param $host String: Host:IP to get socket for
1038          *
1039          * @return Mixed: IO Stream or false
1040          * @access private
1041          */
1042         function sock_to_host( $host ) {
1043                 if ( isset( $this->_cache_sock[$host] ) ) {
1044                         return $this->_cache_sock[$host];
1045                 }
1046
1047                 $sock = null;
1048                 $now = time();
1049                 list( $ip, /* $port */) = explode( ':', $host );
1050                 if ( isset( $this->_host_dead[$host] ) && $this->_host_dead[$host] > $now ||
1051                         isset( $this->_host_dead[$ip] ) && $this->_host_dead[$ip] > $now
1052                 ) {
1053                         return null;
1054                 }
1055
1056                 if ( !$this->_connect_sock( $sock, $host ) ) {
1057                         $this->_dead_host( $host );
1058                         return null;
1059                 }
1060
1061                 // Do not buffer writes
1062                 stream_set_write_buffer( $sock, 0 );
1063
1064                 $this->_cache_sock[$host] = $sock;
1065
1066                 return $this->_cache_sock[$host];
1067         }
1068
1069         /**
1070          * @param $str string
1071          */
1072         function _debugprint( $str ) {
1073                 print( $str );
1074         }
1075
1076         /**
1077          * Write to a stream, timing out after the correct amount of time
1078          *
1079          * @return Boolean: false on failure, true on success
1080          */
1081         /*
1082         function _safe_fwrite( $f, $buf, $len = false ) {
1083                 stream_set_blocking( $f, 0 );
1084
1085                 if ( $len === false ) {
1086                         wfDebug( "Writing " . strlen( $buf ) . " bytes\n" );
1087                         $bytesWritten = fwrite( $f, $buf );
1088                 } else {
1089                         wfDebug( "Writing $len bytes\n" );
1090                         $bytesWritten = fwrite( $f, $buf, $len );
1091                 }
1092                 $n = stream_select( $r = null, $w = array( $f ), $e = null, 10, 0 );
1093                 #   $this->_timeout_seconds, $this->_timeout_microseconds );
1094
1095                 wfDebug( "stream_select returned $n\n" );
1096                 stream_set_blocking( $f, 1 );
1097                 return $n == 1;
1098                 return $bytesWritten;
1099         }*/
1100
1101         /**
1102          * Original behaviour
1103          * @param $f
1104          * @param $buf
1105          * @param $len bool
1106          * @return int
1107          */
1108         function _safe_fwrite( $f, $buf, $len = false ) {
1109                 if ( $len === false ) {
1110                         $bytesWritten = fwrite( $f, $buf );
1111                 } else {
1112                         $bytesWritten = fwrite( $f, $buf, $len );
1113                 }
1114                 return $bytesWritten;
1115         }
1116
1117         /**
1118          * Flush the read buffer of a stream
1119          * @param $f Resource
1120          */
1121         function _flush_read_buffer( $f ) {
1122                 if ( !is_resource( $f ) ) {
1123                         return;
1124                 }
1125                 $n = stream_select( $r = array( $f ), $w = null, $e = null, 0, 0 );
1126                 while ( $n == 1 && !feof( $f ) ) {
1127                         fread( $f, 1024 );
1128                         $n = stream_select( $r = array( $f ), $w = null, $e = null, 0, 0 );
1129                 }
1130         }
1131
1132         // }}}
1133         // }}}
1134         // }}}
1135 }
1136
1137 // vim: sts=3 sw=3 et
1138
1139 // }}}
1140
1141 class MemCachedClientforWiki extends MWMemcached {
1142
1143         function _debugprint( $text ) {
1144                 global $wgDebugLogGroups;
1145                 if( !isset( $wgDebugLogGroups['memcached'] ) ) {
1146                         # Prefix message since it will end up in main debug log file
1147                         $text = "memcached: $text";
1148                 }
1149                 wfDebugLog( 'memcached', $text );
1150         }
1151 }