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 // $TCAnet$
  37 //
  38
  39 /**
  40  * This is the PHP client for memcached - a distributed memory cache daemon.
  41  * More information is available at http://www.danga.com/memcached/
  42  *
  43  * Usage example:
  44  *
  45  * require_once 'memcached.php';
  46  *
  47  * $mc = new MWMemcached(array(
  48  *              'servers' => array('127.0.0.1:10000',
  49  *                                 array('192.0.0.1:10010', 2),
  50  *                                 '127.0.0.1:10020'),
  51  *              'debug'   => false,
  52  *              'compress_threshold' => 10240,
  53  *              'persistant' => true));
  54  *
  55  * $mc->add('key', array('some', 'array'));
  56  * $mc->replace('key', 'some random string');
  57  * $val = $mc->get('key');
  58  *
  59  * @author  Ryan T. Dean <rtdean@cytherianage.net>
  60  * @version 0.1.2
  61  */
  62
  63 // {{{ requirements
  64 // }}}
  65
  66 // {{{ class MWMemcached
  67 /**
  68  * memcached client class implemented using (p)fsockopen()
  69  *
  70  * @author  Ryan T. Dean <rtdean@cytherianage.net>
  71  * @ingroup Cache
  72  */
  73 class MWMemcached {
  74         // {{{ properties
  75         // {{{ public
  76
  77         // {{{ constants
  78         // {{{ flags
  79
  80         /**
  81          * Flag: indicates data is serialized
  82          */
  83         const SERIALIZED = 1;
  84
  85         /**
  86          * Flag: indicates data is compressed
  87          */
  88         const COMPRESSED = 2;
  89
  90         // }}}
  91
  92         /**
  93          * Minimum savings to store data compressed
  94          */
  95         const COMPRESSION_SAVINGS = 0.20;
  96
  97         // }}}
  98
  99
 100         /**
 101          * Command statistics
 102          *
 103          * @var     array
 104          * @access  public
 105          */
 106         var $stats;
 107
 108         // }}}
 109         // {{{ private
 110
 111         /**
 112          * Cached Sockets that are connected
 113          *
 114          * @var     array
 115          * @access  private
 116          */
 117         var $_cache_sock;
 118
 119         /**
 120          * Current debug status; 0 - none to 9 - profiling
 121          *
 122          * @var     boolean
 123          * @access  private
 124          */
 125         var $_debug;
 126
 127         /**
 128          * Dead hosts, assoc array, 'host'=>'unixtime when ok to check again'
 129          *
 130          * @var     array
 131          * @access  private
 132          */
 133         var $_host_dead;
 134
 135         /**
 136          * Is compression available?
 137          *
 138          * @var     boolean
 139          * @access  private
 140          */
 141         var $_have_zlib;
 142
 143         /**
 144          * Do we want to use compression?
 145          *
 146          * @var     boolean
 147          * @access  private
 148          */
 149         var $_compress_enable;
 150
 151         /**
 152          * At how many bytes should we compress?
 153          *
 154          * @var     integer
 155          * @access  private
 156          */
 157         var $_compress_threshold;
 158
 159         /**
 160          * Are we using persistant links?
 161          *
 162          * @var     boolean
 163          * @access  private
 164          */
 165         var $_persistant;
 166
 167         /**
 168          * If only using one server; contains ip:port to connect to
 169          *
 170          * @var     string
 171          * @access  private
 172          */
 173         var $_single_sock;
 174
 175         /**
 176          * Array containing ip:port or array(ip:port, weight)
 177          *
 178          * @var     array
 179          * @access  private
 180          */
 181         var $_servers;
 182
 183         /**
 184          * Our bit buckets
 185          *
 186          * @var     array
 187          * @access  private
 188          */
 189         var $_buckets;
 190
 191         /**
 192          * Total # of bit buckets we have
 193          *
 194          * @var     integer
 195          * @access  private
 196          */
 197         var $_bucketcount;
 198
 199         /**
 200          * # of total servers we have
 201          *
 202          * @var     integer
 203          * @access  private
 204          */
 205         var $_active;
 206
 207         /**
 208          * Stream timeout in seconds. Applies for example to fread()
 209          *
 210          * @var     integer
 211          * @access  private
 212          */
 213         var $_timeout_seconds;
 214
 215         /**
 216          * Stream timeout in microseconds
 217          *
 218          * @var     integer
 219          * @access  private
 220          */
 221         var $_timeout_microseconds;
 222
 223         /**
 224          * Connect timeout in seconds
 225          */
 226         var $_connect_timeout;
 227
 228         /**
 229          * Number of connection attempts for each server
 230          */
 231         var $_connect_attempts;
 232
 233         // }}}
 234         // }}}
 235         // {{{ methods
 236         // {{{ public functions
 237         // {{{ memcached()
 238
 239         /**
 240          * Memcache initializer
 241          *
 242          * @param   array    $args    Associative array of settings
 243          *
 244          * @return  mixed
 245          */
 246         public function __construct( $args ) {
 247                 global $wgMemCachedTimeout;
 248                 $this->set_servers( @$args['servers'] );
 249                 $this->_debug = @$args['debug'];
 250                 $this->stats = array();
 251                 $this->_compress_threshold = @$args['compress_threshold'];
 252                 $this->_persistant = array_key_exists( 'persistant', $args ) ? ( @$args['persistant'] ) : 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 = $wgMemCachedTimeout;
 261
 262                 $this->_connect_timeout = 0.01;
 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   string  $key     Key to set with data
 274          * @param   mixed   $val     Value to store
 275          * @param   integer $exp     (optional) Time to expire data at
 276          *
 277          * @return  boolean
 278          */
 279         public function add( $key, $val, $exp = 0 ) {
 280                 return $this->_set( 'add', $key, $val, $exp );
 281         }
 282
 283         // }}}
 284         // {{{ decr()
 285
 286         /**
 287          * Decriment a value stored on the memcache server
 288          *
 289          * @param   string   $key     Key to decriment
 290          * @param   integer  $amt     (optional) Amount to decriment
 291          *
 292          * @return  mixed    FALSE on failure, value on success
 293          */
 294         public function decr( $key, $amt = 1 ) {
 295                 return $this->_incrdecr( 'decr', $key, $amt );
 296         }
 297
 298         // }}}
 299         // {{{ delete()
 300
 301         /**
 302          * Deletes a key from the server, optionally after $time
 303          *
 304          * @param   string   $key     Key to delete
 305          * @param   integer  $time    (optional) How long to wait before deleting
 306          *
 307          * @return  boolean  TRUE on success, FALSE on failure
 308          */
 309         public function delete( $key, $time = 0 ) {
 310                 if ( !$this->_active ) {
 311                         return false;
 312                 }
 313
 314                 $sock = $this->get_sock( $key );
 315                 if ( !is_resource( $sock ) ) {
 316                         return false;
 317                 }
 318
 319                 $key = is_array( $key ) ? $key[1] : $key;
 320
 321                 @$this->stats['delete']++;
 322                 $cmd = "delete $key $time\r\n";
 323                 if( !$this->_safe_fwrite( $sock, $cmd, strlen( $cmd ) ) ) {
 324                         $this->_dead_sock( $sock );
 325                         return false;
 326                 }
 327                 $res = trim( fgets( $sock ) );
 328
 329                 if ( $this->_debug ) {
 330                         $this->_debugprint( sprintf( "MemCache: delete %s (%s)\n", $key, $res ) );
 331                 }
 332
 333                 if ( $res == "DELETED" ) {
 334                         return true;
 335                 }
 336                 return false;
 337         }
 338
 339         // }}}
 340         // {{{ disconnect_all()
 341
 342         /**
 343          * Disconnects all connected sockets
 344          */
 345         public function disconnect_all() {
 346                 foreach ( $this->_cache_sock as $sock ) {
 347                         fclose( $sock );
 348                 }
 349
 350                 $this->_cache_sock = array();
 351         }
 352
 353         // }}}
 354         // {{{ enable_compress()
 355
 356         /**
 357          * Enable / Disable compression
 358          *
 359          * @param   boolean  $enable  TRUE to enable, FALSE to disable
 360          */
 361         public function enable_compress( $enable ) {
 362                 $this->_compress_enable = $enable;
 363         }
 364
 365         // }}}
 366         // {{{ forget_dead_hosts()
 367
 368         /**
 369          * Forget about all of the dead hosts
 370          */
 371         public function forget_dead_hosts() {
 372                 $this->_host_dead = array();
 373         }
 374
 375         // }}}
 376         // {{{ get()
 377
 378         /**
 379          * Retrieves the value associated with the key from the memcache server
 380          *
 381          * @param  string   $key     Key to retrieve
 382          *
 383          * @return  mixed
 384          */
 385         public function get( $key ) {
 386                 wfProfileIn( __METHOD__ );
 387
 388                 if ( $this->_debug ) {
 389                         $this->_debugprint( "get($key)\n" );
 390                 }
 391
 392                 if ( !$this->_active ) {
 393                         wfProfileOut( __METHOD__ );
 394                         return false;
 395                 }
 396
 397                 $sock = $this->get_sock( $key );
 398
 399                 if ( !is_resource( $sock ) ) {
 400                         wfProfileOut( __METHOD__ );
 401                         return false;
 402                 }
 403
 404                 @$this->stats['get']++;
 405
 406                 $cmd = "get $key\r\n";
 407                 if ( !$this->_safe_fwrite( $sock, $cmd, strlen( $cmd ) ) ) {
 408                         $this->_dead_sock( $sock );
 409                         wfProfileOut( __METHOD__ );
 410                         return false;
 411                 }
 412
 413                 $val = array();
 414                 $this->_load_items( $sock, $val );
 415
 416                 if ( $this->_debug ) {
 417                         foreach ( $val as $k => $v ) {
 418                                 $this->_debugprint( sprintf( "MemCache: sock %s got %s\n", serialize( $sock ), $k ) );
 419                         }
 420                 }
 421
 422                 wfProfileOut( __METHOD__ );
 423                 return @$val[$key];
 424         }
 425
 426         // }}}
 427         // {{{ get_multi()
 428
 429         /**
 430          * Get multiple keys from the server(s)
 431          *
 432          * @param   array    $keys    Keys to retrieve
 433          *
 434          * @return  array
 435          */
 436         public function get_multi( $keys ) {
 437                 if ( !$this->_active ) {
 438                         return false;
 439                 }
 440
 441                 @$this->stats['get_multi']++;
 442                 $sock_keys = array();
 443
 444                 foreach ( $keys as $key ) {
 445                         $sock = $this->get_sock( $key );
 446                         if ( !is_resource( $sock ) ) {
 447                                 continue;
 448                         }
 449                         $key = is_array( $key ) ? $key[1] : $key;
 450                         if ( !isset( $sock_keys[$sock] ) ) {
 451                                 $sock_keys[$sock] = array();
 452                                 $socks[] = $sock;
 453                         }
 454                         $sock_keys[$sock][] = $key;
 455                 }
 456
 457                 // Send out the requests
 458                 foreach ( $socks as $sock ) {
 459                         $cmd = 'get';
 460                         foreach ( $sock_keys[$sock] as $key ) {
 461                                 $cmd .= ' ' . $key;
 462                         }
 463                         $cmd .= "\r\n";
 464
 465                         if ( $this->_safe_fwrite( $sock, $cmd, strlen( $cmd ) ) ) {
 466                                 $gather[] = $sock;
 467                         } else {
 468                                 $this->_dead_sock( $sock );
 469                         }
 470                 }
 471
 472                 // Parse responses
 473                 $val = array();
 474                 foreach ( $gather as $sock ) {
 475                         $this->_load_items( $sock, $val );
 476                 }
 477
 478                 if ( $this->_debug ) {
 479                         foreach ( $val as $k => $v ) {
 480                                 $this->_debugprint( sprintf( "MemCache: got %s\n", $k ) );
 481                         }
 482                 }
 483
 484                 return $val;
 485         }
 486
 487         // }}}
 488         // {{{ incr()
 489
 490         /**
 491          * Increments $key (optionally) by $amt
 492          *
 493          * @param   string   $key     Key to increment
 494          * @param   integer  $amt     (optional) amount to increment
 495          *
 496          * @return  integer  New key value?
 497          */
 498         public function incr( $key, $amt = 1 ) {
 499                 return $this->_incrdecr( 'incr', $key, $amt );
 500         }
 501
 502         // }}}
 503         // {{{ replace()
 504
 505         /**
 506          * Overwrites an existing value for key; only works if key is already set
 507          *
 508          * @param   string   $key     Key to set value as
 509          * @param   mixed    $value   Value to store
 510          * @param   integer  $exp     (optional) Experiation time
 511          *
 512          * @return  boolean
 513          */
 514         public function replace( $key, $value, $exp = 0 ) {
 515                 return $this->_set( 'replace', $key, $value, $exp );
 516         }
 517
 518         // }}}
 519         // {{{ run_command()
 520
 521         /**
 522          * Passes through $cmd to the memcache server connected by $sock; returns
 523          * output as an array (null array if no output)
 524          *
 525          * NOTE: due to a possible bug in how PHP reads while using fgets(), each
 526          *       line may not be terminated by a \r\n.  More specifically, my testing
 527          *       has shown that, on FreeBSD at least, each line is terminated only
 528          *       with a \n.  This is with the PHP flag auto_detect_line_endings set
 529          *       to falase (the default).
 530          *
 531          * @param   resource $sock    Socket to send command on
 532          * @param   string   $cmd     Command to run
 533          *
 534          * @return  array    Output array
 535          * @access  public
 536          */
 537         function run_command( $sock, $cmd ) {
 538                 if ( !is_resource( $sock ) ) {
 539                         return array();
 540                 }
 541
 542                 if ( !$this->_safe_fwrite( $sock, $cmd, strlen( $cmd ) ) ) {
 543                         return array();
 544                 }
 545
 546                 while ( true ) {
 547                         $res = fgets( $sock );
 548                         $ret[] = $res;
 549                         if ( preg_match( '/^END/', $res ) ) {
 550                                 break;
 551                         }
 552                         if ( strlen( $res ) == 0 ) {
 553                                 break;
 554                         }
 555                 }
 556                 return $ret;
 557         }
 558
 559         // }}}
 560         // {{{ set()
 561
 562         /**
 563          * Unconditionally sets a key to a given value in the memcache.  Returns true
 564          * if set successfully.
 565          *
 566          * @param   string   $key     Key to set value as
 567          * @param   mixed    $value   Value to set
 568          * @param   integer  $exp     (optional) Experiation time
 569          *
 570          * @return  boolean  TRUE on success
 571          */
 572         public function set( $key, $value, $exp = 0 ) {
 573                 return $this->_set( 'set', $key, $value, $exp );
 574         }
 575
 576         // }}}
 577         // {{{ set_compress_threshold()
 578
 579         /**
 580          * Sets the compression threshold
 581          *
 582          * @param   integer  $thresh  Threshold to compress if larger than
 583          */
 584         public function set_compress_threshold( $thresh ) {
 585                 $this->_compress_threshold = $thresh;
 586         }
 587
 588         // }}}
 589         // {{{ set_debug()
 590
 591         /**
 592          * Sets the debug flag
 593          *
 594          * @param   boolean  $dbg     TRUE for debugging, FALSE otherwise
 595          *
 596          * @see     MWMemcached::__construct
 597          */
 598         public function set_debug( $dbg ) {
 599                 $this->_debug = $dbg;
 600         }
 601
 602         // }}}
 603         // {{{ set_servers()
 604
 605         /**
 606          * Sets the server list to distribute key gets and puts between
 607          *
 608          * @param   array    $list    Array of servers to connect to
 609          *
 610          * @see     MWMemcached::__construct()
 611          */
 612         public function set_servers( $list ) {
 613                 $this->_servers = $list;
 614                 $this->_active = count( $list );
 615                 $this->_buckets = null;
 616                 $this->_bucketcount = 0;
 617
 618                 $this->_single_sock = null;
 619                 if ( $this->_active == 1 ) {
 620                         $this->_single_sock = $this->_servers[0];
 621                 }
 622         }
 623
 624         /**
 625          * Sets the timeout for new connections
 626          *
 627          * @param   integer  $seconds Number of seconds
 628          * @param   integer  $microseconds  Number of microseconds
 629          */
 630         public function set_timeout( $seconds, $microseconds ) {
 631                 $this->_timeout_seconds = $seconds;
 632                 $this->_timeout_microseconds = $microseconds;
 633         }
 634
 635         // }}}
 636         // }}}
 637         // {{{ private methods
 638         // {{{ _close_sock()
 639
 640         /**
 641          * Close the specified socket
 642          *
 643          * @param   string   $sock    Socket to close
 644          *
 645          * @access  private
 646          */
 647         function _close_sock( $sock ) {
 648                 $host = array_search( $sock, $this->_cache_sock );
 649                 fclose( $this->_cache_sock[$host] );
 650                 unset( $this->_cache_sock[$host] );
 651         }
 652
 653         // }}}
 654         // {{{ _connect_sock()
 655
 656         /**
 657          * Connects $sock to $host, timing out after $timeout
 658          *
 659          * @param   integer  $sock    Socket to connect
 660          * @param   string   $host    Host:IP to connect to
 661          *
 662          * @return  boolean
 663          * @access  private
 664          */
 665         function _connect_sock( &$sock, $host ) {
 666                 list( $ip, $port ) = explode( ':', $host );
 667                 $sock = false;
 668                 $timeout = $this->_connect_timeout;
 669                 $errno = $errstr = null;
 670                 for( $i = 0; !$sock && $i < $this->_connect_attempts; $i++ ) {
 671                         if ( $this->_persistant == 1 ) {
 672                                 $sock = @pfsockopen( $ip, $port, $errno, $errstr, $timeout );
 673                         } else {
 674                                 $sock = @fsockopen( $ip, $port, $errno, $errstr, $timeout );
 675                         }
 676                 }
 677                 if ( !$sock ) {
 678                         if ( $this->_debug ) {
 679                                 $this->_debugprint( "Error connecting to $host: $errstr\n" );
 680                         }
 681                         return false;
 682                 }
 683
 684                 // Initialise timeout
 685                 stream_set_timeout( $sock, $this->_timeout_seconds, $this->_timeout_microseconds );
 686
 687                 return true;
 688         }
 689
 690         // }}}
 691         // {{{ _dead_sock()
 692
 693         /**
 694          * Marks a host as dead until 30-40 seconds in the future
 695          *
 696          * @param   string   $sock    Socket to mark as dead
 697          *
 698          * @access  private
 699          */
 700         function _dead_sock( $sock ) {
 701                 $host = array_search( $sock, $this->_cache_sock );
 702                 $this->_dead_host( $host );
 703         }
 704
 705         function _dead_host( $host ) {
 706                 @list( $ip, /* $port */) = explode( ':', $host );
 707                 $this->_host_dead[$ip] = time() + 30 + intval( rand( 0, 10 ) );
 708                 $this->_host_dead[$host] = $this->_host_dead[$ip];
 709                 unset( $this->_cache_sock[$host] );
 710         }
 711
 712         // }}}
 713         // {{{ get_sock()
 714
 715         /**
 716          * get_sock
 717          *
 718          * @param   string   $key     Key to retrieve value for;
 719          *
 720          * @return  mixed    resource on success, false on failure
 721          * @access  private
 722          */
 723         function get_sock( $key ) {
 724                 if ( !$this->_active ) {
 725                         return false;
 726                 }
 727
 728                 if ( $this->_single_sock !== null ) {
 729                         $this->_flush_read_buffer( $this->_single_sock );
 730                         return $this->sock_to_host( $this->_single_sock );
 731                 }
 732
 733                 $hv = is_array( $key ) ? intval( $key[0] ) : $this->_hashfunc( $key );
 734
 735                 if ( $this->_buckets === null ) {
 736                         foreach ( $this->_servers as $v ) {
 737                                 if ( is_array( $v ) ) {
 738                                         for( $i = 0; $i < $v[1]; $i++ ) {
 739                                                 $bu[] = $v[0];
 740                                         }
 741                                 } else {
 742                                         $bu[] = $v;
 743                                 }
 744                         }
 745                         $this->_buckets = $bu;
 746                         $this->_bucketcount = count( $bu );
 747                 }
 748
 749                 $realkey = is_array( $key ) ? $key[1] : $key;
 750                 for( $tries = 0; $tries < 20; $tries++ ) {
 751                         $host = $this->_buckets[$hv % $this->_bucketcount];
 752                         $sock = $this->sock_to_host( $host );
 753                         if ( is_resource( $sock ) ) {
 754                                 $this->_flush_read_buffer( $sock );
 755                                 return $sock;
 756                         }
 757                         $hv = $this->_hashfunc( $hv . $realkey );
 758                 }
 759
 760                 return false;
 761         }
 762
 763         // }}}
 764         // {{{ _hashfunc()
 765
 766         /**
 767          * Creates a hash integer       based on the $key
 768          *
 769          * @param   string   $key     Key to hash
 770          *
 771          * @return  integer  Hash value
 772          * @access  private
 773          */
 774         function _hashfunc( $key ) {
 775                 # Hash function must on [0,0x7ffffff]
 776                 # We take the first 31 bits of the MD5 hash, which unlike the hash
 777                 # function used in a previous version of this client, works
 778                 return hexdec( substr( md5( $key ), 0, 8 ) ) & 0x7fffffff;
 779         }
 780
 781         // }}}
 782         // {{{ _incrdecr()
 783
 784         /**
 785          * Perform increment/decriment on $key
 786          *
 787          * @param   string   $cmd     Command to perform
 788          * @param   string   $key     Key to perform it on
 789          * @param   integer  $amt     Amount to adjust
 790          *
 791          * @return  integer     New value of $key
 792          * @access  private
 793          */
 794         function _incrdecr( $cmd, $key, $amt = 1 ) {
 795                 if ( !$this->_active ) {
 796                         return null;
 797                 }
 798
 799                 $sock = $this->get_sock( $key );
 800                 if ( !is_resource( $sock ) ) {
 801                         return null;
 802                 }
 803
 804                 $key = is_array( $key ) ? $key[1] : $key;
 805                 @$this->stats[$cmd]++;
 806                 if ( !$this->_safe_fwrite( $sock, "$cmd $key $amt\r\n" ) ) {
 807                         return $this->_dead_sock( $sock );
 808                 }
 809
 810                 $line = fgets( $sock );
 811                 $match = array();
 812                 if ( !preg_match( '/^(\d+)/', $line, $match ) ) {
 813                         return null;
 814                 }
 815                 return $match[1];
 816         }
 817
 818         // }}}
 819         // {{{ _load_items()
 820
 821         /**
 822          * Load items into $ret from $sock
 823          *
 824          * @param   resource $sock    Socket to read from
 825          * @param   array    $ret     Returned values
 826          *
 827          * @access  private
 828          */
 829         function _load_items( $sock, &$ret ) {
 830                 while ( 1 ) {
 831                         $decl = fgets( $sock );
 832                         if ( $decl == "END\r\n" ) {
 833                                 return true;
 834                         } elseif ( preg_match( '/^VALUE (\S+) (\d+) (\d+)\r\n$/', $decl, $match ) ) {
 835                                 list( $rkey, $flags, $len ) = array( $match[1], $match[2], $match[3] );
 836                                 $bneed = $len + 2;
 837                                 $offset = 0;
 838
 839                                 while ( $bneed > 0 ) {
 840                                         $data = fread( $sock, $bneed );
 841                                         $n = strlen( $data );
 842                                         if ( $n == 0 ) {
 843                                                 break;
 844                                         }
 845                                         $offset += $n;
 846                                         $bneed -= $n;
 847                                         @$ret[$rkey] .= $data;
 848                                 }
 849
 850                                 if ( $offset != $len + 2 ) {
 851                                         // Something is borked!
 852                                         if ( $this->_debug ) {
 853                                                 $this->_debugprint( sprintf( "Something is borked!  key %s expecting %d got %d length\n", $rkey, $len + 2, $offset ) );
 854                                         }
 855
 856                                         unset( $ret[$rkey] );
 857                                         $this->_close_sock( $sock );
 858                                         return false;
 859                                 }
 860
 861                                 if ( $this->_have_zlib && $flags & self::COMPRESSED ) {
 862                                         $ret[$rkey] = gzuncompress( $ret[$rkey] );
 863                                 }
 864
 865                                 $ret[$rkey] = rtrim( $ret[$rkey] );
 866
 867                                 if ( $flags & self::SERIALIZED ) {
 868                                         $ret[$rkey] = unserialize( $ret[$rkey] );
 869                                 }
 870
 871                         } else {
 872                                 $this->_debugprint( "Error parsing memcached response\n" );
 873                                 return 0;
 874                         }
 875                 }
 876         }
 877
 878         // }}}
 879         // {{{ _set()
 880
 881         /**
 882          * Performs the requested storage operation to the memcache server
 883          *
 884          * @param   string   $cmd     Command to perform
 885          * @param   string   $key     Key to act on
 886          * @param   mixed    $val     What we need to store
 887          * @param   integer  $exp     When it should expire
 888          *
 889          * @return  boolean
 890          * @access  private
 891          */
 892         function _set( $cmd, $key, $val, $exp ) {
 893                 if ( !$this->_active ) {
 894                         return false;
 895                 }
 896
 897                 $sock = $this->get_sock( $key );
 898                 if ( !is_resource( $sock ) ) {
 899                         return false;
 900                 }
 901
 902                 @$this->stats[$cmd]++;
 903
 904                 $flags = 0;
 905
 906                 if ( !is_scalar( $val ) ) {
 907                         $val = serialize( $val );
 908                         $flags |= self::SERIALIZED;
 909                         if ( $this->_debug ) {
 910                                 $this->_debugprint( sprintf( "client: serializing data as it is not scalar\n" ) );
 911                         }
 912                 }
 913
 914                 $len = strlen( $val );
 915
 916                 if ( $this->_have_zlib && $this->_compress_enable &&
 917                          $this->_compress_threshold && $len >= $this->_compress_threshold )
 918                 {
 919                         $c_val = gzcompress( $val, 9 );
 920                         $c_len = strlen( $c_val );
 921
 922                         if ( $c_len < $len * ( 1 - self::COMPRESSION_SAVINGS ) ) {
 923                                 if ( $this->_debug ) {
 924                                         $this->_debugprint( sprintf( "client: compressing data; was %d bytes is now %d bytes\n", $len, $c_len ) );
 925                                 }
 926                                 $val = $c_val;
 927                                 $len = $c_len;
 928                                 $flags |= self::COMPRESSED;
 929                         }
 930                 }
 931                 if ( !$this->_safe_fwrite( $sock, "$cmd $key $flags $exp $len\r\n$val\r\n" ) ) {
 932                         return $this->_dead_sock( $sock );
 933                 }
 934
 935                 $line = trim( fgets( $sock ) );
 936
 937                 if ( $this->_debug ) {
 938                         $this->_debugprint( sprintf( "%s %s (%s)\n", $cmd, $key, $line ) );
 939                 }
 940                 if ( $line == "STORED" ) {
 941                         return true;
 942                 }
 943                 return false;
 944         }
 945
 946         // }}}
 947         // {{{ sock_to_host()
 948
 949         /**
 950          * Returns the socket for the host
 951          *
 952          * @param   string   $host    Host:IP to get socket for
 953          *
 954          * @return  mixed    IO Stream or false
 955          * @access  private
 956          */
 957         function sock_to_host( $host ) {
 958                 if ( isset( $this->_cache_sock[$host] ) ) {
 959                         return $this->_cache_sock[$host];
 960                 }
 961
 962                 $sock = null;
 963                 $now = time();
 964                 list( $ip, /* $port */) = explode( ':', $host );
 965                 if ( isset( $this->_host_dead[$host] ) && $this->_host_dead[$host] > $now ||
 966                         isset( $this->_host_dead[$ip] ) && $this->_host_dead[$ip] > $now
 967                 ) {
 968                         return null;
 969                 }
 970
 971                 if ( !$this->_connect_sock( $sock, $host ) ) {
 972                         return $this->_dead_host( $host );
 973                 }
 974
 975                 // Do not buffer writes
 976                 stream_set_write_buffer( $sock, 0 );
 977
 978                 $this->_cache_sock[$host] = $sock;
 979
 980                 return $this->_cache_sock[$host];
 981         }
 982
 983         function _debugprint( $str ) {
 984                 print( $str );
 985         }
 986
 987         /**
 988          * Write to a stream, timing out after the correct amount of time
 989          *
 990          * @return bool false on failure, true on success
 991          */
 992         /*
 993         function _safe_fwrite( $f, $buf, $len = false ) {
 994                 stream_set_blocking( $f, 0 );
 995
 996                 if ( $len === false ) {
 997                         wfDebug( "Writing " . strlen( $buf ) . " bytes\n" );
 998                         $bytesWritten = fwrite( $f, $buf );
 999                 } else {
1000                         wfDebug( "Writing $len bytes\n" );
1001                         $bytesWritten = fwrite( $f, $buf, $len );
1002                 }
1003                 $n = stream_select( $r = null, $w = array( $f ), $e = null, 10, 0 );
1004                 #   $this->_timeout_seconds, $this->_timeout_microseconds );
1005
1006                 wfDebug( "stream_select returned $n\n" );
1007                 stream_set_blocking( $f, 1 );
1008                 return $n == 1;
1009                 return $bytesWritten;
1010         }*/
1011
1012         /**
1013          * Original behaviour
1014          */
1015         function _safe_fwrite( $f, $buf, $len = false ) {
1016                 if ( $len === false ) {
1017                         $bytesWritten = fwrite( $f, $buf );
1018                 } else {
1019                         $bytesWritten = fwrite( $f, $buf, $len );
1020                 }
1021                 return $bytesWritten;
1022         }
1023
1024         /**
1025          * Flush the read buffer of a stream
1026          */
1027         function _flush_read_buffer( $f ) {
1028                 if ( !is_resource( $f ) ) {
1029                         return;
1030                 }
1031                 $n = stream_select( $r = array( $f ), $w = null, $e = null, 0, 0 );
1032                 while ( $n == 1 && !feof( $f ) ) {
1033                         fread( $f, 1024 );
1034                         $n = stream_select( $r = array( $f ), $w = null, $e = null, 0, 0 );
1035                 }
1036         }
1037
1038         // }}}
1039         // }}}
1040         // }}}
1041 }
1042
1043 // vim: sts=3 sw=3 et
1044
1045 // }}}
1046
1047 class MemCachedClientforWiki extends MWMemcached {
1048         function _debugprint( $text ) {
1049                 wfDebug( "memcached: $text" );
1050         }
1051 }