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" || $res == "NOT_FOUND" ) {
 342                         return true;
 343                 }
 344
 345                 return false;
 346         }
 347
 348         /**
 349          * @param $key
 350          * @param $timeout int
 351          * @return bool
 352          */
 353         public function lock( $key, $timeout = 0 ) {
 354                 /* stub */
 355                 return true;
 356         }
 357
 358         /**
 359          * @param $key
 360          * @return bool
 361          */
 362         public function unlock( $key ) {
 363                 /* stub */
 364                 return true;
 365         }
 366
 367         // }}}
 368         // {{{ disconnect_all()
 369
 370         /**
 371          * Disconnects all connected sockets
 372          */
 373         public function disconnect_all() {
 374                 foreach ( $this->_cache_sock as $sock ) {
 375                         fclose( $sock );
 376                 }
 377
 378                 $this->_cache_sock = array();
 379         }
 380
 381         // }}}
 382         // {{{ enable_compress()
 383
 384         /**
 385          * Enable / Disable compression
 386          *
 387          * @param $enable Boolean: TRUE to enable, FALSE to disable
 388          */
 389         public function enable_compress( $enable ) {
 390                 $this->_compress_enable = $enable;
 391         }
 392
 393         // }}}
 394         // {{{ forget_dead_hosts()
 395
 396         /**
 397          * Forget about all of the dead hosts
 398          */
 399         public function forget_dead_hosts() {
 400                 $this->_host_dead = array();
 401         }
 402
 403         // }}}
 404         // {{{ get()
 405
 406         /**
 407          * Retrieves the value associated with the key from the memcache server
 408          *
 409          * @param $key array|string key to retrieve
 410          *
 411          * @return Mixed
 412          */
 413         public function get( $key ) {
 414                 wfProfileIn( __METHOD__ );
 415
 416                 if ( $this->_debug ) {
 417                         $this->_debugprint( "get($key)\n" );
 418                 }
 419
 420                 if ( !$this->_active ) {
 421                         wfProfileOut( __METHOD__ );
 422                         return false;
 423                 }
 424
 425                 $sock = $this->get_sock( $key );
 426
 427                 if ( !is_resource( $sock ) ) {
 428                         wfProfileOut( __METHOD__ );
 429                         return false;
 430                 }
 431
 432                 $key = is_array( $key ) ? $key[1] : $key;
 433                 if ( isset( $this->stats['get'] ) ) {
 434                         $this->stats['get']++;
 435                 } else {
 436                         $this->stats['get'] = 1;
 437                 }
 438
 439                 $cmd = "get $key\r\n";
 440                 if ( !$this->_safe_fwrite( $sock, $cmd, strlen( $cmd ) ) ) {
 441                         $this->_dead_sock( $sock );
 442                         wfProfileOut( __METHOD__ );
 443                         return false;
 444                 }
 445
 446                 $val = array();
 447                 $this->_load_items( $sock, $val );
 448
 449                 if ( $this->_debug ) {
 450                         foreach ( $val as $k => $v ) {
 451                                 $this->_debugprint( sprintf( "MemCache: sock %s got %s\n", serialize( $sock ), $k ) );
 452                         }
 453                 }
 454
 455                 $value = false;
 456                 if ( isset( $val[$key] ) ) {
 457                         $value = $val[$key];
 458                 }
 459                 wfProfileOut( __METHOD__ );
 460                 return $value;
 461         }
 462
 463         // }}}
 464         // {{{ get_multi()
 465
 466         /**
 467          * Get multiple keys from the server(s)
 468          *
 469          * @param $keys Array: keys to retrieve
 470          *
 471          * @return Array
 472          */
 473         public function get_multi( $keys ) {
 474                 if ( !$this->_active ) {
 475                         return false;
 476                 }
 477
 478                 if ( isset( $this->stats['get_multi'] ) ) {
 479                         $this->stats['get_multi']++;
 480                 } else {
 481                         $this->stats['get_multi'] = 1;
 482                 }
 483                 $sock_keys = array();
 484                 $socks = array();
 485                 foreach ( $keys as $key ) {
 486                         $sock = $this->get_sock( $key );
 487                         if ( !is_resource( $sock ) ) {
 488                                 continue;
 489                         }
 490                         $key = is_array( $key ) ? $key[1] : $key;
 491                         if ( !isset( $sock_keys[$sock] ) ) {
 492                                 $sock_keys[$sock] = array();
 493                                 $socks[] = $sock;
 494                         }
 495                         $sock_keys[$sock][] = $key;
 496                 }
 497
 498                 $gather = array();
 499                 // Send out the requests
 500                 foreach ( $socks as $sock ) {
 501                         $cmd = 'get';
 502                         foreach ( $sock_keys[$sock] as $key ) {
 503                                 $cmd .= ' ' . $key;
 504                         }
 505                         $cmd .= "\r\n";
 506
 507                         if ( $this->_safe_fwrite( $sock, $cmd, strlen( $cmd ) ) ) {
 508                                 $gather[] = $sock;
 509                         } else {
 510                                 $this->_dead_sock( $sock );
 511                         }
 512                 }
 513
 514                 // Parse responses
 515                 $val = array();
 516                 foreach ( $gather as $sock ) {
 517                         $this->_load_items( $sock, $val );
 518                 }
 519
 520                 if ( $this->_debug ) {
 521                         foreach ( $val as $k => $v ) {
 522                                 $this->_debugprint( sprintf( "MemCache: got %s\n", $k ) );
 523                         }
 524                 }
 525
 526                 return $val;
 527         }
 528
 529         // }}}
 530         // {{{ incr()
 531
 532         /**
 533          * Increments $key (optionally) by $amt
 534          *
 535          * @param $key String: key to increment
 536          * @param $amt Integer: (optional) amount to increment
 537          *
 538          * @return Integer: null if the key does not exist yet (this does NOT
 539          * create new mappings if the key does not exist). If the key does
 540          * exist, this returns the new value for that key.
 541          */
 542         public function incr( $key, $amt = 1 ) {
 543                 return $this->_incrdecr( 'incr', $key, $amt );
 544         }
 545
 546         // }}}
 547         // {{{ replace()
 548
 549         /**
 550          * Overwrites an existing value for key; only works if key is already set
 551          *
 552          * @param $key String: key to set value as
 553          * @param $value Mixed: value to store
 554          * @param $exp Integer: (optional) Expiration time. This can be a number of seconds
 555          * to cache for (up to 30 days inclusive).  Any timespans of 30 days + 1 second or
 556          * longer must be the timestamp of the time at which the mapping should expire. It
 557          * is safe to use timestamps in all cases, regardless of exipration
 558          * eg: strtotime("+3 hour")
 559          *
 560          * @return Boolean
 561          */
 562         public function replace( $key, $value, $exp = 0 ) {
 563                 return $this->_set( 'replace', $key, $value, $exp );
 564         }
 565
 566         // }}}
 567         // {{{ run_command()
 568
 569         /**
 570          * Passes through $cmd to the memcache server connected by $sock; returns
 571          * output as an array (null array if no output)
 572          *
 573          * NOTE: due to a possible bug in how PHP reads while using fgets(), each
 574          *       line may not be terminated by a \r\n.  More specifically, my testing
 575          *       has shown that, on FreeBSD at least, each line is terminated only
 576          *       with a \n.  This is with the PHP flag auto_detect_line_endings set
 577          *       to falase (the default).
 578          *
 579          * @param $sock Resource: socket to send command on
 580          * @param $cmd String: command to run
 581          *
 582          * @return Array: output array
 583          */
 584         public function run_command( $sock, $cmd ) {
 585                 if ( !is_resource( $sock ) ) {
 586                         return array();
 587                 }
 588
 589                 if ( !$this->_safe_fwrite( $sock, $cmd, strlen( $cmd ) ) ) {
 590                         return array();
 591                 }
 592
 593                 $ret = array();
 594                 while ( true ) {
 595                         $res = fgets( $sock );
 596                         $ret[] = $res;
 597                         if ( preg_match( '/^END/', $res ) ) {
 598                                 break;
 599                         }
 600                         if ( strlen( $res ) == 0 ) {
 601                                 break;
 602                         }
 603                 }
 604                 return $ret;
 605         }
 606
 607         // }}}
 608         // {{{ set()
 609
 610         /**
 611          * Unconditionally sets a key to a given value in the memcache.  Returns true
 612          * if set successfully.
 613          *
 614          * @param $key String: key to set value as
 615          * @param $value Mixed: value to set
 616          * @param $exp Integer: (optional) Expiration time. This can be a number of seconds
 617          * to cache for (up to 30 days inclusive).  Any timespans of 30 days + 1 second or
 618          * longer must be the timestamp of the time at which the mapping should expire. It
 619          * is safe to use timestamps in all cases, regardless of exipration
 620          * eg: strtotime("+3 hour")
 621          *
 622          * @return Boolean: TRUE on success
 623          */
 624         public function set( $key, $value, $exp = 0 ) {
 625                 return $this->_set( 'set', $key, $value, $exp );
 626         }
 627
 628         // }}}
 629         // {{{ set_compress_threshold()
 630
 631         /**
 632          * Sets the compression threshold
 633          *
 634          * @param $thresh Integer: threshold to compress if larger than
 635          */
 636         public function set_compress_threshold( $thresh ) {
 637                 $this->_compress_threshold = $thresh;
 638         }
 639
 640         // }}}
 641         // {{{ set_debug()
 642
 643         /**
 644          * Sets the debug flag
 645          *
 646          * @param $dbg Boolean: TRUE for debugging, FALSE otherwise
 647          *
 648          * @see     MWMemcached::__construct
 649          */
 650         public function set_debug( $dbg ) {
 651                 $this->_debug = $dbg;
 652         }
 653
 654         // }}}
 655         // {{{ set_servers()
 656
 657         /**
 658          * Sets the server list to distribute key gets and puts between
 659          *
 660          * @param $list Array of servers to connect to
 661          *
 662          * @see     MWMemcached::__construct()
 663          */
 664         public function set_servers( $list ) {
 665                 $this->_servers = $list;
 666                 $this->_active = count( $list );
 667                 $this->_buckets = null;
 668                 $this->_bucketcount = 0;
 669
 670                 $this->_single_sock = null;
 671                 if ( $this->_active == 1 ) {
 672                         $this->_single_sock = $this->_servers[0];
 673                 }
 674         }
 675
 676         /**
 677          * Sets the timeout for new connections
 678          *
 679          * @param $seconds Integer: number of seconds
 680          * @param $microseconds Integer: number of microseconds
 681          */
 682         public function set_timeout( $seconds, $microseconds ) {
 683                 $this->_timeout_seconds = $seconds;
 684                 $this->_timeout_microseconds = $microseconds;
 685         }
 686
 687         // }}}
 688         // }}}
 689         // {{{ private methods
 690         // {{{ _close_sock()
 691
 692         /**
 693          * Close the specified socket
 694          *
 695          * @param $sock String: socket to close
 696          *
 697          * @access  private
 698          */
 699         function _close_sock( $sock ) {
 700                 $host = array_search( $sock, $this->_cache_sock );
 701                 fclose( $this->_cache_sock[$host] );
 702                 unset( $this->_cache_sock[$host] );
 703         }
 704
 705         // }}}
 706         // {{{ _connect_sock()
 707
 708         /**
 709          * Connects $sock to $host, timing out after $timeout
 710          *
 711          * @param $sock Integer: socket to connect
 712          * @param $host String: Host:IP to connect to
 713          *
 714          * @return  boolean
 715          * @access  private
 716          */
 717         function _connect_sock( &$sock, $host ) {
 718                 list( $ip, $port ) = explode( ':', $host );
 719                 $sock = false;
 720                 $timeout = $this->_connect_timeout;
 721                 $errno = $errstr = null;
 722                 for( $i = 0; !$sock && $i < $this->_connect_attempts; $i++ ) {
 723                         wfSuppressWarnings();
 724                         if ( $this->_persistent == 1 ) {
 725                                 $sock = pfsockopen( $ip, $port, $errno, $errstr, $timeout );
 726                         } else {
 727                                 $sock = fsockopen( $ip, $port, $errno, $errstr, $timeout );
 728                         }
 729                         wfRestoreWarnings();
 730                 }
 731                 if ( !$sock ) {
 732                         if ( $this->_debug ) {
 733                                 $this->_debugprint( "Error connecting to $host: $errstr\n" );
 734                         }
 735                         return false;
 736                 }
 737
 738                 // Initialise timeout
 739                 stream_set_timeout( $sock, $this->_timeout_seconds, $this->_timeout_microseconds );
 740
 741                 return true;
 742         }
 743
 744         // }}}
 745         // {{{ _dead_sock()
 746
 747         /**
 748          * Marks a host as dead until 30-40 seconds in the future
 749          *
 750          * @param $sock String: socket to mark as dead
 751          *
 752          * @access  private
 753          */
 754         function _dead_sock( $sock ) {
 755                 $host = array_search( $sock, $this->_cache_sock );
 756                 $this->_dead_host( $host );
 757         }
 758
 759         /**
 760          * @param $host
 761          */
 762         function _dead_host( $host ) {
 763                 $parts = explode( ':', $host );
 764                 $ip = $parts[0];
 765                 $this->_host_dead[$ip] = time() + 30 + intval( rand( 0, 10 ) );
 766                 $this->_host_dead[$host] = $this->_host_dead[$ip];
 767                 unset( $this->_cache_sock[$host] );
 768         }
 769
 770         // }}}
 771         // {{{ get_sock()
 772
 773         /**
 774          * get_sock
 775          *
 776          * @param $key String: key to retrieve value for;
 777          *
 778          * @return Mixed: resource on success, false on failure
 779          * @access private
 780          */
 781         function get_sock( $key ) {
 782                 if ( !$this->_active ) {
 783                         return false;
 784                 }
 785
 786                 if ( $this->_single_sock !== null ) {
 787                         $this->_flush_read_buffer( $this->_single_sock );
 788                         return $this->sock_to_host( $this->_single_sock );
 789                 }
 790
 791                 $hv = is_array( $key ) ? intval( $key[0] ) : $this->_hashfunc( $key );
 792                 if ( $this->_buckets === null ) {
 793                         $bu = array();
 794                         foreach ( $this->_servers as $v ) {
 795                                 if ( is_array( $v ) ) {
 796                                         for( $i = 0; $i < $v[1]; $i++ ) {
 797                                                 $bu[] = $v[0];
 798                                         }
 799                                 } else {
 800                                         $bu[] = $v;
 801                                 }
 802                         }
 803                         $this->_buckets = $bu;
 804                         $this->_bucketcount = count( $bu );
 805                 }
 806
 807                 $realkey = is_array( $key ) ? $key[1] : $key;
 808                 for( $tries = 0; $tries < 20; $tries++ ) {
 809                         $host = $this->_buckets[$hv % $this->_bucketcount];
 810                         $sock = $this->sock_to_host( $host );
 811                         if ( is_resource( $sock ) ) {
 812                                 $this->_flush_read_buffer( $sock );
 813                                 return $sock;
 814                         }
 815                         $hv = $this->_hashfunc( $hv . $realkey );
 816                 }
 817
 818                 return false;
 819         }
 820
 821         // }}}
 822         // {{{ _hashfunc()
 823
 824         /**
 825          * Creates a hash integer based on the $key
 826          *
 827          * @param $key String: key to hash
 828          *
 829          * @return Integer: hash value
 830          * @access private
 831          */
 832         function _hashfunc( $key ) {
 833                 # Hash function must on [0,0x7ffffff]
 834                 # We take the first 31 bits of the MD5 hash, which unlike the hash
 835                 # function used in a previous version of this client, works
 836                 return hexdec( substr( md5( $key ), 0, 8 ) ) & 0x7fffffff;
 837         }
 838
 839         // }}}
 840         // {{{ _incrdecr()
 841
 842         /**
 843          * Perform increment/decriment on $key
 844          *
 845          * @param $cmd String command to perform
 846          * @param $key String|array key to perform it on
 847          * @param $amt Integer amount to adjust
 848          *
 849          * @return Integer: new value of $key
 850          * @access private
 851          */
 852         function _incrdecr( $cmd, $key, $amt = 1 ) {
 853                 if ( !$this->_active ) {
 854                         return null;
 855                 }
 856
 857                 $sock = $this->get_sock( $key );
 858                 if ( !is_resource( $sock ) ) {
 859                         return null;
 860                 }
 861
 862                 $key = is_array( $key ) ? $key[1] : $key;
 863                 if ( isset( $this->stats[$cmd] ) ) {
 864                         $this->stats[$cmd]++;
 865                 } else {
 866                         $this->stats[$cmd] = 1;
 867                 }
 868                 if ( !$this->_safe_fwrite( $sock, "$cmd $key $amt\r\n" ) ) {
 869                         $this->_dead_sock( $sock );
 870                         return null;
 871                 }
 872
 873                 $line = fgets( $sock );
 874                 $match = array();
 875                 if ( !preg_match( '/^(\d+)/', $line, $match ) ) {
 876                         return null;
 877                 }
 878                 return $match[1];
 879         }
 880
 881         // }}}
 882         // {{{ _load_items()
 883
 884         /**
 885          * Load items into $ret from $sock
 886          *
 887          * @param $sock Resource: socket to read from
 888          * @param $ret Array: returned values
 889          *
 890          * @return bool|int
 891          * @access private
 892          */
 893         function _load_items( $sock, &$ret ) {
 894                 while ( 1 ) {
 895                         $decl = fgets( $sock );
 896                         if ( $decl == "END\r\n" ) {
 897                                 return true;
 898                         } elseif ( preg_match( '/^VALUE (\S+) (\d+) (\d+)\r\n$/', $decl, $match ) ) {
 899                                 list( $rkey, $flags, $len ) = array( $match[1], $match[2], $match[3] );
 900                                 $bneed = $len + 2;
 901                                 $offset = 0;
 902
 903                                 while ( $bneed > 0 ) {
 904                                         $data = fread( $sock, $bneed );
 905                                         $n = strlen( $data );
 906                                         if ( $n == 0 ) {
 907                                                 break;
 908                                         }
 909                                         $offset += $n;
 910                                         $bneed -= $n;
 911                                         if ( isset( $ret[$rkey] ) ) {
 912                                                 $ret[$rkey] .= $data;
 913                                         } else {
 914                                                 $ret[$rkey] = $data;
 915                                         }
 916                                 }
 917
 918                                 if ( $offset != $len + 2 ) {
 919                                         // Something is borked!
 920                                         if ( $this->_debug ) {
 921                                                 $this->_debugprint( sprintf( "Something is borked!  key %s expecting %d got %d length\n", $rkey, $len + 2, $offset ) );
 922                                         }
 923
 924                                         unset( $ret[$rkey] );
 925                                         $this->_close_sock( $sock );
 926                                         return false;
 927                                 }
 928
 929                                 if ( $this->_have_zlib && $flags & self::COMPRESSED ) {
 930                                         $ret[$rkey] = gzuncompress( $ret[$rkey] );
 931                                 }
 932
 933                                 $ret[$rkey] = rtrim( $ret[$rkey] );
 934
 935                                 if ( $flags & self::SERIALIZED ) {
 936                                         $ret[$rkey] = unserialize( $ret[$rkey] );
 937                                 }
 938
 939                         } else {
 940                                 $this->_debugprint( "Error parsing memcached response\n" );
 941                                 return 0;
 942                         }
 943                 }
 944         }
 945
 946         // }}}
 947         // {{{ _set()
 948
 949         /**
 950          * Performs the requested storage operation to the memcache server
 951          *
 952          * @param $cmd String: command to perform
 953          * @param $key String: key to act on
 954          * @param $val Mixed: what we need to store
 955          * @param $exp Integer: (optional) Expiration time. This can be a number of seconds
 956          * to cache for (up to 30 days inclusive).  Any timespans of 30 days + 1 second or
 957          * longer must be the timestamp of the time at which the mapping should expire. It
 958          * is safe to use timestamps in all cases, regardless of exipration
 959          * eg: strtotime("+3 hour")
 960          *
 961          * @return Boolean
 962          * @access private
 963          */
 964         function _set( $cmd, $key, $val, $exp ) {
 965                 if ( !$this->_active ) {
 966                         return false;
 967                 }
 968
 969                 $sock = $this->get_sock( $key );
 970                 if ( !is_resource( $sock ) ) {
 971                         return false;
 972                 }
 973
 974                 if ( isset( $this->stats[$cmd] ) ) {
 975                         $this->stats[$cmd]++;
 976                 } else {
 977                         $this->stats[$cmd] = 1;
 978                 }
 979
 980                 // TTLs higher than 30 days will be detected as absolute TTLs
 981                 // (UNIX timestamps), and will result in the cache entry being
 982                 // discarded immediately because the expiry is in the past.
 983                 // Clamp expiries >30d at 30d, unless they're >=1e9 in which
 984                 // case they are likely to really be absolute (1e9 = 2011-09-09)
 985                 if ( $exp > 2592000 && $exp < 1000000000 ) {
 986                         $exp = 2592000;
 987                 }
 988
 989                 $flags = 0;
 990
 991                 if ( !is_scalar( $val ) ) {
 992                         $val = serialize( $val );
 993                         $flags |= self::SERIALIZED;
 994                         if ( $this->_debug ) {
 995                                 $this->_debugprint( sprintf( "client: serializing data as it is not scalar\n" ) );
 996                         }
 997                 }
 998
 999                 $len = strlen( $val );
1000
1001                 if ( $this->_have_zlib && $this->_compress_enable &&
1002                          $this->_compress_threshold && $len >= $this->_compress_threshold )
1003                 {
1004                         $c_val = gzcompress( $val, 9 );
1005                         $c_len = strlen( $c_val );
1006
1007                         if ( $c_len < $len * ( 1 - self::COMPRESSION_SAVINGS ) ) {
1008                                 if ( $this->_debug ) {
1009                                         $this->_debugprint( sprintf( "client: compressing data; was %d bytes is now %d bytes\n", $len, $c_len ) );
1010                                 }
1011                                 $val = $c_val;
1012                                 $len = $c_len;
1013                                 $flags |= self::COMPRESSED;
1014                         }
1015                 }
1016                 if ( !$this->_safe_fwrite( $sock, "$cmd $key $flags $exp $len\r\n$val\r\n" ) ) {
1017                         $this->_dead_sock( $sock );
1018                         return false;
1019                 }
1020
1021                 $line = trim( fgets( $sock ) );
1022
1023                 if ( $this->_debug ) {
1024                         $this->_debugprint( sprintf( "%s %s (%s)\n", $cmd, $key, $line ) );
1025                 }
1026                 if ( $line == "STORED" ) {
1027                         return true;
1028                 }
1029                 return false;
1030         }
1031
1032         // }}}
1033         // {{{ sock_to_host()
1034
1035         /**
1036          * Returns the socket for the host
1037          *
1038          * @param $host String: Host:IP to get socket for
1039          *
1040          * @return Mixed: IO Stream or false
1041          * @access private
1042          */
1043         function sock_to_host( $host ) {
1044                 if ( isset( $this->_cache_sock[$host] ) ) {
1045                         return $this->_cache_sock[$host];
1046                 }
1047
1048                 $sock = null;
1049                 $now = time();
1050                 list( $ip, /* $port */) = explode( ':', $host );
1051                 if ( isset( $this->_host_dead[$host] ) && $this->_host_dead[$host] > $now ||
1052                         isset( $this->_host_dead[$ip] ) && $this->_host_dead[$ip] > $now
1053                 ) {
1054                         return null;
1055                 }
1056
1057                 if ( !$this->_connect_sock( $sock, $host ) ) {
1058                         $this->_dead_host( $host );
1059                         return null;
1060                 }
1061
1062                 // Do not buffer writes
1063                 stream_set_write_buffer( $sock, 0 );
1064
1065                 $this->_cache_sock[$host] = $sock;
1066
1067                 return $this->_cache_sock[$host];
1068         }
1069
1070         /**
1071          * @param $str string
1072          */
1073         function _debugprint( $str ) {
1074                 print( $str );
1075         }
1076
1077         /**
1078          * Write to a stream, timing out after the correct amount of time
1079          *
1080          * @return Boolean: false on failure, true on success
1081          */
1082         /*
1083         function _safe_fwrite( $f, $buf, $len = false ) {
1084                 stream_set_blocking( $f, 0 );
1085
1086                 if ( $len === false ) {
1087                         wfDebug( "Writing " . strlen( $buf ) . " bytes\n" );
1088                         $bytesWritten = fwrite( $f, $buf );
1089                 } else {
1090                         wfDebug( "Writing $len bytes\n" );
1091                         $bytesWritten = fwrite( $f, $buf, $len );
1092                 }
1093                 $n = stream_select( $r = null, $w = array( $f ), $e = null, 10, 0 );
1094                 #   $this->_timeout_seconds, $this->_timeout_microseconds );
1095
1096                 wfDebug( "stream_select returned $n\n" );
1097                 stream_set_blocking( $f, 1 );
1098                 return $n == 1;
1099                 return $bytesWritten;
1100         }*/
1101
1102         /**
1103          * Original behaviour
1104          * @param $f
1105          * @param $buf
1106          * @param $len bool
1107          * @return int
1108          */
1109         function _safe_fwrite( $f, $buf, $len = false ) {
1110                 if ( $len === false ) {
1111                         $bytesWritten = fwrite( $f, $buf );
1112                 } else {
1113                         $bytesWritten = fwrite( $f, $buf, $len );
1114                 }
1115                 return $bytesWritten;
1116         }
1117
1118         /**
1119          * Flush the read buffer of a stream
1120          * @param $f Resource
1121          */
1122         function _flush_read_buffer( $f ) {
1123                 if ( !is_resource( $f ) ) {
1124                         return;
1125                 }
1126                 $n = stream_select( $r = array( $f ), $w = null, $e = null, 0, 0 );
1127                 while ( $n == 1 && !feof( $f ) ) {
1128                         fread( $f, 1024 );
1129                         $n = stream_select( $r = array( $f ), $w = null, $e = null, 0, 0 );
1130                 }
1131         }
1132
1133         // }}}
1134         // }}}
1135         // }}}
1136 }
1137
1138 // vim: sts=3 sw=3 et
1139
1140 // }}}
1141
1142 class MemCachedClientforWiki extends MWMemcached {
1143
1144         function _debugprint( $text ) {
1145                 global $wgDebugLogGroups;
1146                 if( !isset( $wgDebugLogGroups['memcached'] ) ) {
1147                         # Prefix message since it will end up in main debug log file
1148                         $text = "memcached: $text";
1149                 }
1150                 wfDebugLog( 'memcached', $text );
1151         }
1152 }