includes/memcached-client.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  *              'persistant' => 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 persistant links?
 162          *
 163          * @var     boolean
 164          * @access  private
 165          */
 166         var $_persistant;
 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 Associative array of settings
 244          *
 245          * @return  mixed
 246          */
 247         public function __construct( $args ) {
 248                 global $wgMemCachedTimeout;
 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->_persistant = isset( $args['persistant'] ) ? $args['persistant'] : 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 = $wgMemCachedTimeout;
 262
 263                 $this->_connect_timeout = 0.01;
 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 $key String: 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 exipration
 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          * Decrement a value stored on the memcache server
 293          *
 294          * @param $key String: key to decriment
 295          * @param $amt Integer: (optional) amount to decriment
 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 $key String: 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->_safe_fwrite( $sock, $cmd, strlen( $cmd ) ) ) {
 333                         $this->_dead_sock( $sock );
 334                         return false;
 335                 }
 336                 $res = trim( fgets( $sock ) );
 337
 338                 if ( $this->_debug ) {
 339                         $this->_debugprint( sprintf( "MemCache: delete %s (%s)\n", $key, $res ) );
 340                 }
 341
 342                 if ( $res == "DELETED" ) {
 343                         return true;
 344                 }
 345                 return false;
 346         }
 347
 348         // }}}
 349         // {{{ disconnect_all()
 350
 351         /**
 352          * Disconnects all connected sockets
 353          */
 354         public function disconnect_all() {
 355                 foreach ( $this->_cache_sock as $sock ) {
 356                         fclose( $sock );
 357                 }
 358
 359                 $this->_cache_sock = array();
 360         }
 361
 362         // }}}
 363         // {{{ enable_compress()
 364
 365         /**
 366          * Enable / Disable compression
 367          *
 368          * @param $enable Boolean: TRUE to enable, FALSE to disable
 369          */
 370         public function enable_compress( $enable ) {
 371                 $this->_compress_enable = $enable;
 372         }
 373
 374         // }}}
 375         // {{{ forget_dead_hosts()
 376
 377         /**
 378          * Forget about all of the dead hosts
 379          */
 380         public function forget_dead_hosts() {
 381                 $this->_host_dead = array();
 382         }
 383
 384         // }}}
 385         // {{{ get()
 386
 387         /**
 388          * Retrieves the value associated with the key from the memcache server
 389          *
 390          * @param $key Mixed: key to retrieve
 391          *
 392          * @return Mixed
 393          */
 394         public function get( $key ) {
 395                 wfProfileIn( __METHOD__ );
 396
 397                 if ( $this->_debug ) {
 398                         $this->_debugprint( "get($key)\n" );
 399                 }
 400
 401                 if ( !$this->_active ) {
 402                         wfProfileOut( __METHOD__ );
 403                         return false;
 404                 }
 405
 406                 $sock = $this->get_sock( $key );
 407
 408                 if ( !is_resource( $sock ) ) {
 409                         wfProfileOut( __METHOD__ );
 410                         return false;
 411                 }
 412
 413                 if ( isset( $this->stats['get'] ) ) {
 414                         $this->stats['get']++;
 415                 } else {
 416                         $this->stats['get'] = 1;
 417                 }
 418
 419                 $cmd = "get $key\r\n";
 420                 if ( !$this->_safe_fwrite( $sock, $cmd, strlen( $cmd ) ) ) {
 421                         $this->_dead_sock( $sock );
 422                         wfProfileOut( __METHOD__ );
 423                         return false;
 424                 }
 425
 426                 $val = array();
 427                 $this->_load_items( $sock, $val );
 428
 429                 if ( $this->_debug ) {
 430                         foreach ( $val as $k => $v ) {
 431                                 $this->_debugprint( sprintf( "MemCache: sock %s got %s\n", serialize( $sock ), $k ) );
 432                         }
 433                 }
 434
 435                 wfProfileOut( __METHOD__ );
 436                 return @$val[$key];
 437         }
 438
 439         // }}}
 440         // {{{ get_multi()
 441
 442         /**
 443          * Get multiple keys from the server(s)
 444          *
 445          * @param $keys Array: keys to retrieve
 446          *
 447          * @return Array
 448          */
 449         public function get_multi( $keys ) {
 450                 if ( !$this->_active ) {
 451                         return false;
 452                 }
 453
 454                 if ( isset( $this->stats['get_multi'] ) ) {
 455                         $this->stats['get_multi']++;
 456                 } else {
 457                         $this->stats['get_multi'] = 1;
 458                 }
 459                 $sock_keys = array();
 460
 461                 foreach ( $keys as $key ) {
 462                         $sock = $this->get_sock( $key );
 463                         if ( !is_resource( $sock ) ) {
 464                                 continue;
 465                         }
 466                         $key = is_array( $key ) ? $key[1] : $key;
 467                         if ( !isset( $sock_keys[$sock] ) ) {
 468                                 $sock_keys[$sock] = array();
 469                                 $socks[] = $sock;
 470                         }
 471                         $sock_keys[$sock][] = $key;
 472                 }
 473
 474                 // Send out the requests
 475                 foreach ( $socks as $sock ) {
 476                         $cmd = 'get';
 477                         foreach ( $sock_keys[$sock] as $key ) {
 478                                 $cmd .= ' ' . $key;
 479                         }
 480                         $cmd .= "\r\n";
 481
 482                         if ( $this->_safe_fwrite( $sock, $cmd, strlen( $cmd ) ) ) {
 483                                 $gather[] = $sock;
 484                         } else {
 485                                 $this->_dead_sock( $sock );
 486                         }
 487                 }
 488
 489                 // Parse responses
 490                 $val = array();
 491                 foreach ( $gather as $sock ) {
 492                         $this->_load_items( $sock, $val );
 493                 }
 494
 495                 if ( $this->_debug ) {
 496                         foreach ( $val as $k => $v ) {
 497                                 $this->_debugprint( sprintf( "MemCache: got %s\n", $k ) );
 498                         }
 499                 }
 500
 501                 return $val;
 502         }
 503
 504         // }}}
 505         // {{{ incr()
 506
 507         /**
 508          * Increments $key (optionally) by $amt
 509          *
 510          * @param $key String: key to increment
 511          * @param $amt Integer: (optional) amount to increment
 512          *
 513          * @return Integer: null if the key does not exist yet (this does NOT
 514          * create new mappings if the key does not exist). If the key does
 515          * exist, this returns the new value for that key.
 516          */
 517         public function incr( $key, $amt = 1 ) {
 518                 return $this->_incrdecr( 'incr', $key, $amt );
 519         }
 520
 521         // }}}
 522         // {{{ replace()
 523
 524         /**
 525          * Overwrites an existing value for key; only works if key is already set
 526          *
 527          * @param $key String: key to set value as
 528          * @param $value Mixed: value to store
 529          * @param $exp Integer: (optional) Expiration time. This can be a number of seconds
 530          * to cache for (up to 30 days inclusive).  Any timespans of 30 days + 1 second or
 531          * longer must be the timestamp of the time at which the mapping should expire. It
 532          * is safe to use timestamps in all cases, regardless of exipration
 533          * eg: strtotime("+3 hour")
 534          *
 535          * @return Boolean
 536          */
 537         public function replace( $key, $value, $exp = 0 ) {
 538                 return $this->_set( 'replace', $key, $value, $exp );
 539         }
 540
 541         // }}}
 542         // {{{ run_command()
 543
 544         /**
 545          * Passes through $cmd to the memcache server connected by $sock; returns
 546          * output as an array (null array if no output)
 547          *
 548          * NOTE: due to a possible bug in how PHP reads while using fgets(), each
 549          *       line may not be terminated by a \r\n.  More specifically, my testing
 550          *       has shown that, on FreeBSD at least, each line is terminated only
 551          *       with a \n.  This is with the PHP flag auto_detect_line_endings set
 552          *       to falase (the default).
 553          *
 554          * @param $sock Ressource: socket to send command on
 555          * @param $cmd String: command to run
 556          *
 557          * @return Array: output array
 558          */
 559         public function run_command( $sock, $cmd ) {
 560                 if ( !is_resource( $sock ) ) {
 561                         return array();
 562                 }
 563
 564                 if ( !$this->_safe_fwrite( $sock, $cmd, strlen( $cmd ) ) ) {
 565                         return array();
 566                 }
 567
 568                 while ( true ) {
 569                         $res = fgets( $sock );
 570                         $ret[] = $res;
 571                         if ( preg_match( '/^END/', $res ) ) {
 572                                 break;
 573                         }
 574                         if ( strlen( $res ) == 0 ) {
 575                                 break;
 576                         }
 577                 }
 578                 return $ret;
 579         }
 580
 581         // }}}
 582         // {{{ set()
 583
 584         /**
 585          * Unconditionally sets a key to a given value in the memcache.  Returns true
 586          * if set successfully.
 587          *
 588          * @param $key String: key to set value as
 589          * @param $value Mixed: value to set
 590          * @param $exp Integer: (optional) Expiration time. This can be a number of seconds
 591          * to cache for (up to 30 days inclusive).  Any timespans of 30 days + 1 second or
 592          * longer must be the timestamp of the time at which the mapping should expire. It
 593          * is safe to use timestamps in all cases, regardless of exipration
 594          * eg: strtotime("+3 hour")
 595          *
 596          * @return Boolean: TRUE on success
 597          */
 598         public function set( $key, $value, $exp = 0 ) {
 599                 return $this->_set( 'set', $key, $value, $exp );
 600         }
 601
 602         // }}}
 603         // {{{ set_compress_threshold()
 604
 605         /**
 606          * Sets the compression threshold
 607          *
 608          * @param $thresh Integer: threshold to compress if larger than
 609          */
 610         public function set_compress_threshold( $thresh ) {
 611                 $this->_compress_threshold = $thresh;
 612         }
 613
 614         // }}}
 615         // {{{ set_debug()
 616
 617         /**
 618          * Sets the debug flag
 619          *
 620          * @param $dbg Boolean: TRUE for debugging, FALSE otherwise
 621          *
 622          * @see     MWMemcached::__construct
 623          */
 624         public function set_debug( $dbg ) {
 625                 $this->_debug = $dbg;
 626         }
 627
 628         // }}}
 629         // {{{ set_servers()
 630
 631         /**
 632          * Sets the server list to distribute key gets and puts between
 633          *
 634          * @param $list Array of servers to connect to
 635          *
 636          * @see     MWMemcached::__construct()
 637          */
 638         public function set_servers( $list ) {
 639                 $this->_servers = $list;
 640                 $this->_active = count( $list );
 641                 $this->_buckets = null;
 642                 $this->_bucketcount = 0;
 643
 644                 $this->_single_sock = null;
 645                 if ( $this->_active == 1 ) {
 646                         $this->_single_sock = $this->_servers[0];
 647                 }
 648         }
 649
 650         /**
 651          * Sets the timeout for new connections
 652          *
 653          * @param $seconds Integer: number of seconds
 654          * @param $microseconds Integer: number of microseconds
 655          */
 656         public function set_timeout( $seconds, $microseconds ) {
 657                 $this->_timeout_seconds = $seconds;
 658                 $this->_timeout_microseconds = $microseconds;
 659         }
 660
 661         // }}}
 662         // }}}
 663         // {{{ private methods
 664         // {{{ _close_sock()
 665
 666         /**
 667          * Close the specified socket
 668          *
 669          * @param $sock String: socket to close
 670          *
 671          * @access  private
 672          */
 673         function _close_sock( $sock ) {
 674                 $host = array_search( $sock, $this->_cache_sock );
 675                 fclose( $this->_cache_sock[$host] );
 676                 unset( $this->_cache_sock[$host] );
 677         }
 678
 679         // }}}
 680         // {{{ _connect_sock()
 681
 682         /**
 683          * Connects $sock to $host, timing out after $timeout
 684          *
 685          * @param $sock Integer: socket to connect
 686          * @param $host String: Host:IP to connect to
 687          *
 688          * @return  boolean
 689          * @access  private
 690          */
 691         function _connect_sock( &$sock, $host ) {
 692                 list( $ip, $port ) = explode( ':', $host );
 693                 $sock = false;
 694                 $timeout = $this->_connect_timeout;
 695                 $errno = $errstr = null;
 696                 for( $i = 0; !$sock && $i < $this->_connect_attempts; $i++ ) {
 697                         wfSuppressWarnings();
 698                         if ( $this->_persistant == 1 ) {
 699                                 $sock = pfsockopen( $ip, $port, $errno, $errstr, $timeout );
 700                         } else {
 701                                 $sock = fsockopen( $ip, $port, $errno, $errstr, $timeout );
 702                         }
 703                         wfRestoreWarnings();
 704                 }
 705                 if ( !$sock ) {
 706                         if ( $this->_debug ) {
 707                                 $this->_debugprint( "Error connecting to $host: $errstr\n" );
 708                         }
 709                         return false;
 710                 }
 711
 712                 // Initialise timeout
 713                 stream_set_timeout( $sock, $this->_timeout_seconds, $this->_timeout_microseconds );
 714
 715                 return true;
 716         }
 717
 718         // }}}
 719         // {{{ _dead_sock()
 720
 721         /**
 722          * Marks a host as dead until 30-40 seconds in the future
 723          *
 724          * @param $sock String: socket to mark as dead
 725          *
 726          * @access  private
 727          */
 728         function _dead_sock( $sock ) {
 729                 $host = array_search( $sock, $this->_cache_sock );
 730                 $this->_dead_host( $host );
 731         }
 732
 733         function _dead_host( $host ) {
 734                 $parts = explode( ':', $host );
 735                 $ip = $parts[0];
 736                 $this->_host_dead[$ip] = time() + 30 + intval( rand( 0, 10 ) );
 737                 $this->_host_dead[$host] = $this->_host_dead[$ip];
 738                 unset( $this->_cache_sock[$host] );
 739         }
 740
 741         // }}}
 742         // {{{ get_sock()
 743
 744         /**
 745          * get_sock
 746          *
 747          * @param $key String: key to retrieve value for;
 748          *
 749          * @return Mixed: resource on success, false on failure
 750          * @access private
 751          */
 752         function get_sock( $key ) {
 753                 if ( !$this->_active ) {
 754                         return false;
 755                 }
 756
 757                 if ( $this->_single_sock !== null ) {
 758                         $this->_flush_read_buffer( $this->_single_sock );
 759                         return $this->sock_to_host( $this->_single_sock );
 760                 }
 761
 762                 $hv = is_array( $key ) ? intval( $key[0] ) : $this->_hashfunc( $key );
 763
 764                 if ( $this->_buckets === null ) {
 765                         foreach ( $this->_servers as $v ) {
 766                                 if ( is_array( $v ) ) {
 767                                         for( $i = 0; $i < $v[1]; $i++ ) {
 768                                                 $bu[] = $v[0];
 769                                         }
 770                                 } else {
 771                                         $bu[] = $v;
 772                                 }
 773                         }
 774                         $this->_buckets = $bu;
 775                         $this->_bucketcount = count( $bu );
 776                 }
 777
 778                 $realkey = is_array( $key ) ? $key[1] : $key;
 779                 for( $tries = 0; $tries < 20; $tries++ ) {
 780                         $host = $this->_buckets[$hv % $this->_bucketcount];
 781                         $sock = $this->sock_to_host( $host );
 782                         if ( is_resource( $sock ) ) {
 783                                 $this->_flush_read_buffer( $sock );
 784                                 return $sock;
 785                         }
 786                         $hv = $this->_hashfunc( $hv . $realkey );
 787                 }
 788
 789                 return false;
 790         }
 791
 792         // }}}
 793         // {{{ _hashfunc()
 794
 795         /**
 796          * Creates a hash integer based on the $key
 797          *
 798          * @param $key String: key to hash
 799          *
 800          * @return Integer: hash value
 801          * @access private
 802          */
 803         function _hashfunc( $key ) {
 804                 # Hash function must on [0,0x7ffffff]
 805                 # We take the first 31 bits of the MD5 hash, which unlike the hash
 806                 # function used in a previous version of this client, works
 807                 return hexdec( substr( md5( $key ), 0, 8 ) ) & 0x7fffffff;
 808         }
 809
 810         // }}}
 811         // {{{ _incrdecr()
 812
 813         /**
 814          * Perform increment/decriment on $key
 815          *
 816          * @param $cmd String: command to perform
 817          * @param $key String: key to perform it on
 818          * @param $amt Integer: amount to adjust
 819          *
 820          * @return Integer: new value of $key
 821          * @access private
 822          */
 823         function _incrdecr( $cmd, $key, $amt = 1 ) {
 824                 if ( !$this->_active ) {
 825                         return null;
 826                 }
 827
 828                 $sock = $this->get_sock( $key );
 829                 if ( !is_resource( $sock ) ) {
 830                         return null;
 831                 }
 832
 833                 $key = is_array( $key ) ? $key[1] : $key;
 834                 if ( isset( $this->stats[$cmd] ) ) {
 835                         $this->stats[$cmd]++;
 836                 } else {
 837                         $this->stats[$cmd] = 1;
 838                 }
 839                 if ( !$this->_safe_fwrite( $sock, "$cmd $key $amt\r\n" ) ) {
 840                         return $this->_dead_sock( $sock );
 841                 }
 842
 843                 $line = fgets( $sock );
 844                 $match = array();
 845                 if ( !preg_match( '/^(\d+)/', $line, $match ) ) {
 846                         return null;
 847                 }
 848                 return $match[1];
 849         }
 850
 851         // }}}
 852         // {{{ _load_items()
 853
 854         /**
 855          * Load items into $ret from $sock
 856          *
 857          * @param $sock Ressource: socket to read from
 858          * @param $ret Array: returned values
 859          *
 860          * @access private
 861          */
 862         function _load_items( $sock, &$ret ) {
 863                 while ( 1 ) {
 864                         $decl = fgets( $sock );
 865                         if ( $decl == "END\r\n" ) {
 866                                 return true;
 867                         } elseif ( preg_match( '/^VALUE (\S+) (\d+) (\d+)\r\n$/', $decl, $match ) ) {
 868                                 list( $rkey, $flags, $len ) = array( $match[1], $match[2], $match[3] );
 869                                 $bneed = $len + 2;
 870                                 $offset = 0;
 871
 872                                 while ( $bneed > 0 ) {
 873                                         $data = fread( $sock, $bneed );
 874                                         $n = strlen( $data );
 875                                         if ( $n == 0 ) {
 876                                                 break;
 877                                         }
 878                                         $offset += $n;
 879                                         $bneed -= $n;
 880                                         if ( isset( $ret[$rkey] ) ) {
 881                                                 $ret[$rkey] .= $data;
 882                                         } else {
 883                                                 $ret[$rkey] = $data;
 884                                         }
 885                                 }
 886
 887                                 if ( $offset != $len + 2 ) {
 888                                         // Something is borked!
 889                                         if ( $this->_debug ) {
 890                                                 $this->_debugprint( sprintf( "Something is borked!  key %s expecting %d got %d length\n", $rkey, $len + 2, $offset ) );
 891                                         }
 892
 893                                         unset( $ret[$rkey] );
 894                                         $this->_close_sock( $sock );
 895                                         return false;
 896                                 }
 897
 898                                 if ( $this->_have_zlib && $flags & self::COMPRESSED ) {
 899                                         $ret[$rkey] = gzuncompress( $ret[$rkey] );
 900                                 }
 901
 902                                 $ret[$rkey] = rtrim( $ret[$rkey] );
 903
 904                                 if ( $flags & self::SERIALIZED ) {
 905                                         $ret[$rkey] = unserialize( $ret[$rkey] );
 906                                 }
 907
 908                         } else {
 909                                 $this->_debugprint( "Error parsing memcached response\n" );
 910                                 return 0;
 911                         }
 912                 }
 913         }
 914
 915         // }}}
 916         // {{{ _set()
 917
 918         /**
 919          * Performs the requested storage operation to the memcache server
 920          *
 921          * @param $cmd String: command to perform
 922          * @param $key String: key to act on
 923          * @param $val Mixed: what we need to store
 924          * @param $exp Integer: (optional) Expiration time. This can be a number of seconds
 925          * to cache for (up to 30 days inclusive).  Any timespans of 30 days + 1 second or
 926          * longer must be the timestamp of the time at which the mapping should expire. It
 927          * is safe to use timestamps in all cases, regardless of exipration
 928          * eg: strtotime("+3 hour")
 929          *
 930          * @return Boolean
 931          * @access private
 932          */
 933         function _set( $cmd, $key, $val, $exp ) {
 934                 if ( !$this->_active ) {
 935                         return false;
 936                 }
 937
 938                 $sock = $this->get_sock( $key );
 939                 if ( !is_resource( $sock ) ) {
 940                         return false;
 941                 }
 942
 943                 if ( isset( $this->stats[$cmd] ) ) {
 944                         $this->stats[$cmd]++;
 945                 } else {
 946                         $this->stats[$cmd] = 1;
 947                 }
 948
 949                 $flags = 0;
 950
 951                 if ( !is_scalar( $val ) ) {
 952                         $val = serialize( $val );
 953                         $flags |= self::SERIALIZED;
 954                         if ( $this->_debug ) {
 955                                 $this->_debugprint( sprintf( "client: serializing data as it is not scalar\n" ) );
 956                         }
 957                 }
 958
 959                 $len = strlen( $val );
 960
 961                 if ( $this->_have_zlib && $this->_compress_enable &&
 962                          $this->_compress_threshold && $len >= $this->_compress_threshold )
 963                 {
 964                         $c_val = gzcompress( $val, 9 );
 965                         $c_len = strlen( $c_val );
 966
 967                         if ( $c_len < $len * ( 1 - self::COMPRESSION_SAVINGS ) ) {
 968                                 if ( $this->_debug ) {
 969                                         $this->_debugprint( sprintf( "client: compressing data; was %d bytes is now %d bytes\n", $len, $c_len ) );
 970                                 }
 971                                 $val = $c_val;
 972                                 $len = $c_len;
 973                                 $flags |= self::COMPRESSED;
 974                         }
 975                 }
 976                 if ( !$this->_safe_fwrite( $sock, "$cmd $key $flags $exp $len\r\n$val\r\n" ) ) {
 977                         return $this->_dead_sock( $sock );
 978                 }
 979
 980                 $line = trim( fgets( $sock ) );
 981
 982                 if ( $this->_debug ) {
 983                         $this->_debugprint( sprintf( "%s %s (%s)\n", $cmd, $key, $line ) );
 984                 }
 985                 if ( $line == "STORED" ) {
 986                         return true;
 987                 }
 988                 return false;
 989         }
 990
 991         // }}}
 992         // {{{ sock_to_host()
 993
 994         /**
 995          * Returns the socket for the host
 996          *
 997          * @param $host String: Host:IP to get socket for
 998          *
 999          * @return Mixed: IO Stream or false
1000          * @access private
1001          */
1002         function sock_to_host( $host ) {
1003                 if ( isset( $this->_cache_sock[$host] ) ) {
1004                         return $this->_cache_sock[$host];
1005                 }
1006
1007                 $sock = null;
1008                 $now = time();
1009                 list( $ip, /* $port */) = explode( ':', $host );
1010                 if ( isset( $this->_host_dead[$host] ) && $this->_host_dead[$host] > $now ||
1011                         isset( $this->_host_dead[$ip] ) && $this->_host_dead[$ip] > $now
1012                 ) {
1013                         return null;
1014                 }
1015
1016                 if ( !$this->_connect_sock( $sock, $host ) ) {
1017                         return $this->_dead_host( $host );
1018                 }
1019
1020                 // Do not buffer writes
1021                 stream_set_write_buffer( $sock, 0 );
1022
1023                 $this->_cache_sock[$host] = $sock;
1024
1025                 return $this->_cache_sock[$host];
1026         }
1027
1028         function _debugprint( $str ) {
1029                 print( $str );
1030         }
1031
1032         /**
1033          * Write to a stream, timing out after the correct amount of time
1034          *
1035          * @return Boolean: false on failure, true on success
1036          */
1037         /*
1038         function _safe_fwrite( $f, $buf, $len = false ) {
1039                 stream_set_blocking( $f, 0 );
1040
1041                 if ( $len === false ) {
1042                         wfDebug( "Writing " . strlen( $buf ) . " bytes\n" );
1043                         $bytesWritten = fwrite( $f, $buf );
1044                 } else {
1045                         wfDebug( "Writing $len bytes\n" );
1046                         $bytesWritten = fwrite( $f, $buf, $len );
1047                 }
1048                 $n = stream_select( $r = null, $w = array( $f ), $e = null, 10, 0 );
1049                 #   $this->_timeout_seconds, $this->_timeout_microseconds );
1050
1051                 wfDebug( "stream_select returned $n\n" );
1052                 stream_set_blocking( $f, 1 );
1053                 return $n == 1;
1054                 return $bytesWritten;
1055         }*/
1056
1057         /**
1058          * Original behaviour
1059          */
1060         function _safe_fwrite( $f, $buf, $len = false ) {
1061                 if ( $len === false ) {
1062                         $bytesWritten = fwrite( $f, $buf );
1063                 } else {
1064                         $bytesWritten = fwrite( $f, $buf, $len );
1065                 }
1066                 return $bytesWritten;
1067         }
1068
1069         /**
1070          * Flush the read buffer of a stream
1071          */
1072         function _flush_read_buffer( $f ) {
1073                 if ( !is_resource( $f ) ) {
1074                         return;
1075                 }
1076                 $n = stream_select( $r = array( $f ), $w = null, $e = null, 0, 0 );
1077                 while ( $n == 1 && !feof( $f ) ) {
1078                         fread( $f, 1024 );
1079                         $n = stream_select( $r = array( $f ), $w = null, $e = null, 0, 0 );
1080                 }
1081         }
1082
1083         // }}}
1084         // }}}
1085         // }}}
1086 }
1087
1088 // vim: sts=3 sw=3 et
1089
1090 // }}}
1091
1092 class MemCachedClientforWiki extends MWMemcached {
1093         function _debugprint( $text ) {
1094                 wfDebug( "memcached: $text" );
1095         }
1096 }