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                 $this->set_servers( @$args['servers'] );
 248                 $this->_debug = @$args['debug'];
 249                 $this->stats = array();
 250                 $this->_compress_threshold = @$args['compress_threshold'];
 251                 $this->_persistant = array_key_exists( 'persistant', $args ) ? ( @$args['persistant'] ) : false;
 252                 $this->_compress_enable = true;
 253                 $this->_have_zlib = function_exists( 'gzcompress' );
 254
 255                 $this->_cache_sock = array();
 256                 $this->_host_dead = array();
 257
 258                 $this->_timeout_seconds = 0;
 259                 $this->_timeout_microseconds = 50000;
 260
 261                 $this->_connect_timeout = 0.01;
 262                 $this->_connect_attempts = 2;
 263         }
 264
 265         // }}}
 266         // {{{ add()
 267
 268         /**
 269          * Adds a key/value to the memcache server if one isn't already set with
 270          * that key
 271          *
 272          * @param   string  $key     Key to set with data
 273          * @param   mixed   $val     Value to store
 274          * @param   integer $exp     (optional) Time to expire data at
 275          *
 276          * @return  boolean
 277          */
 278         public function add( $key, $val, $exp = 0 ) {
 279                 return $this->_set( 'add', $key, $val, $exp );
 280         }
 281
 282         // }}}
 283         // {{{ decr()
 284
 285         /**
 286          * Decriment a value stored on the memcache server
 287          *
 288          * @param   string   $key     Key to decriment
 289          * @param   integer  $amt     (optional) Amount to decriment
 290          *
 291          * @return  mixed    FALSE on failure, value on success
 292          */
 293         public function decr( $key, $amt = 1 ) {
 294                 return $this->_incrdecr( 'decr', $key, $amt );
 295         }
 296
 297         // }}}
 298         // {{{ delete()
 299
 300         /**
 301          * Deletes a key from the server, optionally after $time
 302          *
 303          * @param   string   $key     Key to delete
 304          * @param   integer  $time    (optional) How long to wait before deleting
 305          *
 306          * @return  boolean  TRUE on success, FALSE on failure
 307          */
 308         public function delete( $key, $time = 0 ) {
 309                 if ( !$this->_active ) {
 310                         return false;
 311                 }
 312
 313                 $sock = $this->get_sock( $key );
 314                 if ( !is_resource( $sock ) ) {
 315                         return false;
 316                 }
 317
 318                 $key = is_array( $key ) ? $key[1] : $key;
 319
 320                 @$this->stats['delete']++;
 321                 $cmd = "delete $key $time\r\n";
 322                 if( !$this->_safe_fwrite( $sock, $cmd, strlen( $cmd ) ) ) {
 323                         $this->_dead_sock( $sock );
 324                         return false;
 325                 }
 326                 $res = trim( fgets( $sock ) );
 327
 328                 if ( $this->_debug ) {
 329                         $this->_debugprint( sprintf( "MemCache: delete %s (%s)\n", $key, $res ) );
 330                 }
 331
 332                 if ( $res == "DELETED" ) {
 333                         return true;
 334                 }
 335                 return false;
 336         }
 337
 338         // }}}
 339         // {{{ disconnect_all()
 340
 341         /**
 342          * Disconnects all connected sockets
 343          */
 344         public function disconnect_all() {
 345                 foreach ( $this->_cache_sock as $sock ) {
 346                         fclose( $sock );
 347                 }
 348
 349                 $this->_cache_sock = array();
 350         }
 351
 352         // }}}
 353         // {{{ enable_compress()
 354
 355         /**
 356          * Enable / Disable compression
 357          *
 358          * @param   boolean  $enable  TRUE to enable, FALSE to disable
 359          */
 360         public function enable_compress( $enable ) {
 361                 $this->_compress_enable = $enable;
 362         }
 363
 364         // }}}
 365         // {{{ forget_dead_hosts()
 366
 367         /**
 368          * Forget about all of the dead hosts
 369          */
 370         public function forget_dead_hosts() {
 371                 $this->_host_dead = array();
 372         }
 373
 374         // }}}
 375         // {{{ get()
 376
 377         /**
 378          * Retrieves the value associated with the key from the memcache server
 379          *
 380          * @param  string   $key     Key to retrieve
 381          *
 382          * @return  mixed
 383          */
 384         public function get( $key ) {
 385                 wfProfileIn( __METHOD__ );
 386
 387                 if ( $this->_debug ) {
 388                         $this->_debugprint( "get($key)\n" );
 389                 }
 390
 391                 if ( !$this->_active ) {
 392                         wfProfileOut( __METHOD__ );
 393                         return false;
 394                 }
 395
 396                 $sock = $this->get_sock( $key );
 397
 398                 if ( !is_resource( $sock ) ) {
 399                         wfProfileOut( __METHOD__ );
 400                         return false;
 401                 }
 402
 403                 @$this->stats['get']++;
 404
 405                 $cmd = "get $key\r\n";
 406                 if ( !$this->_safe_fwrite( $sock, $cmd, strlen( $cmd ) ) ) {
 407                         $this->_dead_sock( $sock );
 408                         wfProfileOut( __METHOD__ );
 409                         return false;
 410                 }
 411
 412                 $val = array();
 413                 $this->_load_items( $sock, $val );
 414
 415                 if ( $this->_debug ) {
 416                         foreach ( $val as $k => $v ) {
 417                                 $this->_debugprint( sprintf( "MemCache: sock %s got %s\n", serialize( $sock ), $k ) );
 418                         }
 419                 }
 420
 421                 wfProfileOut( __METHOD__ );
 422                 return @$val[$key];
 423         }
 424
 425         // }}}
 426         // {{{ get_multi()
 427
 428         /**
 429          * Get multiple keys from the server(s)
 430          *
 431          * @param   array    $keys    Keys to retrieve
 432          *
 433          * @return  array
 434          */
 435         public function get_multi( $keys ) {
 436                 if ( !$this->_active ) {
 437                         return false;
 438                 }
 439
 440                 @$this->stats['get_multi']++;
 441                 $sock_keys = array();
 442
 443                 foreach ( $keys as $key ) {
 444                         $sock = $this->get_sock( $key );
 445                         if ( !is_resource( $sock ) ) {
 446                                 continue;
 447                         }
 448                         $key = is_array( $key ) ? $key[1] : $key;
 449                         if ( !isset( $sock_keys[$sock] ) ) {
 450                                 $sock_keys[$sock] = array();
 451                                 $socks[] = $sock;
 452                         }
 453                         $sock_keys[$sock][] = $key;
 454                 }
 455
 456                 // Send out the requests
 457                 foreach ( $socks as $sock ) {
 458                         $cmd = 'get';
 459                         foreach ( $sock_keys[$sock] as $key ) {
 460                                 $cmd .= ' ' . $key;
 461                         }
 462                         $cmd .= "\r\n";
 463
 464                         if ( $this->_safe_fwrite( $sock, $cmd, strlen( $cmd ) ) ) {
 465                                 $gather[] = $sock;
 466                         } else {
 467                                 $this->_dead_sock( $sock );
 468                         }
 469                 }
 470
 471                 // Parse responses
 472                 $val = array();
 473                 foreach ( $gather as $sock ) {
 474                         $this->_load_items( $sock, $val );
 475                 }
 476
 477                 if ( $this->_debug ) {
 478                         foreach ( $val as $k => $v ) {
 479                                 $this->_debugprint( sprintf( "MemCache: got %s\n", $k ) );
 480                         }
 481                 }
 482
 483                 return $val;
 484         }
 485
 486         // }}}
 487         // {{{ incr()
 488
 489         /**
 490          * Increments $key (optionally) by $amt
 491          *
 492          * @param   string   $key     Key to increment
 493          * @param   integer  $amt     (optional) amount to increment
 494          *
 495          * @return  integer  New key value?
 496          */
 497         public function incr( $key, $amt = 1 ) {
 498                 return $this->_incrdecr( 'incr', $key, $amt );
 499         }
 500
 501         // }}}
 502         // {{{ replace()
 503
 504         /**
 505          * Overwrites an existing value for key; only works if key is already set
 506          *
 507          * @param   string   $key     Key to set value as
 508          * @param   mixed    $value   Value to store
 509          * @param   integer  $exp     (optional) Experiation time
 510          *
 511          * @return  boolean
 512          */
 513         public function replace( $key, $value, $exp = 0 ) {
 514                 return $this->_set( 'replace', $key, $value, $exp );
 515         }
 516
 517         // }}}
 518         // {{{ run_command()
 519
 520         /**
 521          * Passes through $cmd to the memcache server connected by $sock; returns
 522          * output as an array (null array if no output)
 523          *
 524          * NOTE: due to a possible bug in how PHP reads while using fgets(), each
 525          *       line may not be terminated by a \r\n.  More specifically, my testing
 526          *       has shown that, on FreeBSD at least, each line is terminated only
 527          *       with a \n.  This is with the PHP flag auto_detect_line_endings set
 528          *       to falase (the default).
 529          *
 530          * @param   resource $sock    Socket to send command on
 531          * @param   string   $cmd     Command to run
 532          *
 533          * @return  array    Output array
 534          * @access  public
 535          */
 536         function run_command( $sock, $cmd ) {
 537                 if ( !is_resource( $sock ) ) {
 538                         return array();
 539                 }
 540
 541                 if ( !$this->_safe_fwrite( $sock, $cmd, strlen( $cmd ) ) ) {
 542                         return array();
 543                 }
 544
 545                 while ( true ) {
 546                         $res = fgets( $sock );
 547                         $ret[] = $res;
 548                         if ( preg_match( '/^END/', $res ) ) {
 549                                 break;
 550                         }
 551                         if ( strlen( $res ) == 0 ) {
 552                                 break;
 553                         }
 554                 }
 555                 return $ret;
 556         }
 557
 558         // }}}
 559         // {{{ set()
 560
 561         /**
 562          * Unconditionally sets a key to a given value in the memcache.  Returns true
 563          * if set successfully.
 564          *
 565          * @param   string   $key     Key to set value as
 566          * @param   mixed    $value   Value to set
 567          * @param   integer  $exp     (optional) Experiation time
 568          *
 569          * @return  boolean  TRUE on success
 570          */
 571         public function set( $key, $value, $exp = 0 ) {
 572                 return $this->_set( 'set', $key, $value, $exp );
 573         }
 574
 575         // }}}
 576         // {{{ set_compress_threshold()
 577
 578         /**
 579          * Sets the compression threshold
 580          *
 581          * @param   integer  $thresh  Threshold to compress if larger than
 582          */
 583         public function set_compress_threshold( $thresh ) {
 584                 $this->_compress_threshold = $thresh;
 585         }
 586
 587         // }}}
 588         // {{{ set_debug()
 589
 590         /**
 591          * Sets the debug flag
 592          *
 593          * @param   boolean  $dbg     TRUE for debugging, FALSE otherwise
 594          *
 595          * @see     MWMemcached::__construct
 596          */
 597         public function set_debug( $dbg ) {
 598                 $this->_debug = $dbg;
 599         }
 600
 601         // }}}
 602         // {{{ set_servers()
 603
 604         /**
 605          * Sets the server list to distribute key gets and puts between
 606          *
 607          * @param   array    $list    Array of servers to connect to
 608          *
 609          * @see     MWMemcached::__construct()
 610          */
 611         public function set_servers( $list ) {
 612                 $this->_servers = $list;
 613                 $this->_active = count( $list );
 614                 $this->_buckets = null;
 615                 $this->_bucketcount = 0;
 616
 617                 $this->_single_sock = null;
 618                 if ( $this->_active == 1 ) {
 619                         $this->_single_sock = $this->_servers[0];
 620                 }
 621         }
 622
 623         /**
 624          * Sets the timeout for new connections
 625          *
 626          * @param   integer  $seconds Number of seconds
 627          * @param   integer  $microseconds  Number of microseconds
 628          */
 629         public function set_timeout( $seconds, $microseconds ) {
 630                 $this->_timeout_seconds = $seconds;
 631                 $this->_timeout_microseconds = $microseconds;
 632         }
 633
 634         // }}}
 635         // }}}
 636         // {{{ private methods
 637         // {{{ _close_sock()
 638
 639         /**
 640          * Close the specified socket
 641          *
 642          * @param   string   $sock    Socket to close
 643          *
 644          * @access  private
 645          */
 646         function _close_sock( $sock ) {
 647                 $host = array_search( $sock, $this->_cache_sock );
 648                 fclose( $this->_cache_sock[$host] );
 649                 unset( $this->_cache_sock[$host] );
 650         }
 651
 652         // }}}
 653         // {{{ _connect_sock()
 654
 655         /**
 656          * Connects $sock to $host, timing out after $timeout
 657          *
 658          * @param   integer  $sock    Socket to connect
 659          * @param   string   $host    Host:IP to connect to
 660          *
 661          * @return  boolean
 662          * @access  private
 663          */
 664         function _connect_sock( &$sock, $host ) {
 665                 list( $ip, $port ) = explode( ':', $host );
 666                 $sock = false;
 667                 $timeout = $this->_connect_timeout;
 668                 $errno = $errstr = null;
 669                 for( $i = 0; !$sock && $i < $this->_connect_attempts; $i++ ) {
 670                         if ( $this->_persistant == 1 ) {
 671                                 $sock = @pfsockopen( $ip, $port, $errno, $errstr, $timeout );
 672                         } else {
 673                                 $sock = @fsockopen( $ip, $port, $errno, $errstr, $timeout );
 674                         }
 675                 }
 676                 if ( !$sock ) {
 677                         if ( $this->_debug ) {
 678                                 $this->_debugprint( "Error connecting to $host: $errstr\n" );
 679                         }
 680                         return false;
 681                 }
 682
 683                 // Initialise timeout
 684                 stream_set_timeout( $sock, $this->_timeout_seconds, $this->_timeout_microseconds );
 685
 686                 return true;
 687         }
 688
 689         // }}}
 690         // {{{ _dead_sock()
 691
 692         /**
 693          * Marks a host as dead until 30-40 seconds in the future
 694          *
 695          * @param   string   $sock    Socket to mark as dead
 696          *
 697          * @access  private
 698          */
 699         function _dead_sock( $sock ) {
 700                 $host = array_search( $sock, $this->_cache_sock );
 701                 $this->_dead_host( $host );
 702         }
 703
 704         function _dead_host( $host ) {
 705                 @list( $ip, /* $port */) = explode( ':', $host );
 706                 $this->_host_dead[$ip] = time() + 30 + intval( rand( 0, 10 ) );
 707                 $this->_host_dead[$host] = $this->_host_dead[$ip];
 708                 unset( $this->_cache_sock[$host] );
 709         }
 710
 711         // }}}
 712         // {{{ get_sock()
 713
 714         /**
 715          * get_sock
 716          *
 717          * @param   string   $key     Key to retrieve value for;
 718          *
 719          * @return  mixed    resource on success, false on failure
 720          * @access  private
 721          */
 722         function get_sock( $key ) {
 723                 if ( !$this->_active ) {
 724                         return false;
 725                 }
 726
 727                 if ( $this->_single_sock !== null ) {
 728                         $this->_flush_read_buffer( $this->_single_sock );
 729                         return $this->sock_to_host( $this->_single_sock );
 730                 }
 731
 732                 $hv = is_array( $key ) ? intval( $key[0] ) : $this->_hashfunc( $key );
 733
 734                 if ( $this->_buckets === null ) {
 735                         foreach ( $this->_servers as $v ) {
 736                                 if ( is_array( $v ) ) {
 737                                         for( $i = 0; $i < $v[1]; $i++ ) {
 738                                                 $bu[] = $v[0];
 739                                         }
 740                                 } else {
 741                                         $bu[] = $v;
 742                                 }
 743                         }
 744                         $this->_buckets = $bu;
 745                         $this->_bucketcount = count( $bu );
 746                 }
 747
 748                 $realkey = is_array( $key ) ? $key[1] : $key;
 749                 for( $tries = 0; $tries < 20; $tries++ ) {
 750                         $host = $this->_buckets[$hv % $this->_bucketcount];
 751                         $sock = $this->sock_to_host( $host );
 752                         if ( is_resource( $sock ) ) {
 753                                 $this->_flush_read_buffer( $sock );
 754                                 return $sock;
 755                         }
 756                         $hv = $this->_hashfunc( $hv . $realkey );
 757                 }
 758
 759                 return false;
 760         }
 761
 762         // }}}
 763         // {{{ _hashfunc()
 764
 765         /**
 766          * Creates a hash integer       based on the $key
 767          *
 768          * @param   string   $key     Key to hash
 769          *
 770          * @return  integer  Hash value
 771          * @access  private
 772          */
 773         function _hashfunc( $key ) {
 774                 # Hash function must on [0,0x7ffffff]
 775                 # We take the first 31 bits of the MD5 hash, which unlike the hash
 776                 # function used in a previous version of this client, works
 777                 return hexdec( substr( md5( $key ), 0, 8 ) ) & 0x7fffffff;
 778         }
 779
 780         // }}}
 781         // {{{ _incrdecr()
 782
 783         /**
 784          * Perform increment/decriment on $key
 785          *
 786          * @param   string   $cmd     Command to perform
 787          * @param   string   $key     Key to perform it on
 788          * @param   integer  $amt     Amount to adjust
 789          *
 790          * @return  integer     New value of $key
 791          * @access  private
 792          */
 793         function _incrdecr( $cmd, $key, $amt = 1 ) {
 794                 if ( !$this->_active ) {
 795                         return null;
 796                 }
 797
 798                 $sock = $this->get_sock( $key );
 799                 if ( !is_resource( $sock ) ) {
 800                         return null;
 801                 }
 802
 803                 $key = is_array( $key ) ? $key[1] : $key;
 804                 @$this->stats[$cmd]++;
 805                 if ( !$this->_safe_fwrite( $sock, "$cmd $key $amt\r\n" ) ) {
 806                         return $this->_dead_sock( $sock );
 807                 }
 808
 809                 $line = fgets( $sock );
 810                 $match = array();
 811                 if ( !preg_match( '/^(\d+)/', $line, $match ) ) {
 812                         return null;
 813                 }
 814                 return $match[1];
 815         }
 816
 817         // }}}
 818         // {{{ _load_items()
 819
 820         /**
 821          * Load items into $ret from $sock
 822          *
 823          * @param   resource $sock    Socket to read from
 824          * @param   array    $ret     Returned values
 825          *
 826          * @access  private
 827          */
 828         function _load_items( $sock, &$ret ) {
 829                 while ( 1 ) {
 830                         $decl = fgets( $sock );
 831                         if ( $decl == "END\r\n" ) {
 832                                 return true;
 833                         } elseif ( preg_match( '/^VALUE (\S+) (\d+) (\d+)\r\n$/', $decl, $match ) ) {
 834                                 list( $rkey, $flags, $len ) = array( $match[1], $match[2], $match[3] );
 835                                 $bneed = $len + 2;
 836                                 $offset = 0;
 837
 838                                 while ( $bneed > 0 ) {
 839                                         $data = fread( $sock, $bneed );
 840                                         $n = strlen( $data );
 841                                         if ( $n == 0 ) {
 842                                                 break;
 843                                         }
 844                                         $offset += $n;
 845                                         $bneed -= $n;
 846                                         @$ret[$rkey] .= $data;
 847                                 }
 848
 849                                 if ( $offset != $len + 2 ) {
 850                                         // Something is borked!
 851                                         if ( $this->_debug ) {
 852                                                 $this->_debugprint( sprintf( "Something is borked!  key %s expecting %d got %d length\n", $rkey, $len + 2, $offset ) );
 853                                         }
 854
 855                                         unset( $ret[$rkey] );
 856                                         $this->_close_sock( $sock );
 857                                         return false;
 858                                 }
 859
 860                                 if ( $this->_have_zlib && $flags & self::COMPRESSED ) {
 861                                         $ret[$rkey] = gzuncompress( $ret[$rkey] );
 862                                 }
 863
 864                                 $ret[$rkey] = rtrim( $ret[$rkey] );
 865
 866                                 if ( $flags & self::SERIALIZED ) {
 867                                         $ret[$rkey] = unserialize( $ret[$rkey] );
 868                                 }
 869
 870                         } else {
 871                                 $this->_debugprint( "Error parsing memcached response\n" );
 872                                 return 0;
 873                         }
 874                 }
 875         }
 876
 877         // }}}
 878         // {{{ _set()
 879
 880         /**
 881          * Performs the requested storage operation to the memcache server
 882          *
 883          * @param   string   $cmd     Command to perform
 884          * @param   string   $key     Key to act on
 885          * @param   mixed    $val     What we need to store
 886          * @param   integer  $exp     When it should expire
 887          *
 888          * @return  boolean
 889          * @access  private
 890          */
 891         function _set( $cmd, $key, $val, $exp ) {
 892                 if ( !$this->_active ) {
 893                         return false;
 894                 }
 895
 896                 $sock = $this->get_sock( $key );
 897                 if ( !is_resource( $sock ) ) {
 898                         return false;
 899                 }
 900
 901                 @$this->stats[$cmd]++;
 902
 903                 $flags = 0;
 904
 905                 if ( !is_scalar( $val ) ) {
 906                         $val = serialize( $val );
 907                         $flags |= self::SERIALIZED;
 908                         if ( $this->_debug ) {
 909                                 $this->_debugprint( sprintf( "client: serializing data as it is not scalar\n" ) );
 910                         }
 911                 }
 912
 913                 $len = strlen( $val );
 914
 915                 if ( $this->_have_zlib && $this->_compress_enable &&
 916                          $this->_compress_threshold && $len >= $this->_compress_threshold )
 917                 {
 918                         $c_val = gzcompress( $val, 9 );
 919                         $c_len = strlen( $c_val );
 920
 921                         if ( $c_len < $len * ( 1 - self::COMPRESSION_SAVINGS ) ) {
 922                                 if ( $this->_debug ) {
 923                                         $this->_debugprint( sprintf( "client: compressing data; was %d bytes is now %d bytes\n", $len, $c_len ) );
 924                                 }
 925                                 $val = $c_val;
 926                                 $len = $c_len;
 927                                 $flags |= self::COMPRESSED;
 928                         }
 929                 }
 930                 if ( !$this->_safe_fwrite( $sock, "$cmd $key $flags $exp $len\r\n$val\r\n" ) ) {
 931                         return $this->_dead_sock( $sock );
 932                 }
 933
 934                 $line = trim( fgets( $sock ) );
 935
 936                 if ( $this->_debug ) {
 937                         $this->_debugprint( sprintf( "%s %s (%s)\n", $cmd, $key, $line ) );
 938                 }
 939                 if ( $line == "STORED" ) {
 940                         return true;
 941                 }
 942                 return false;
 943         }
 944
 945         // }}}
 946         // {{{ sock_to_host()
 947
 948         /**
 949          * Returns the socket for the host
 950          *
 951          * @param   string   $host    Host:IP to get socket for
 952          *
 953          * @return  mixed    IO Stream or false
 954          * @access  private
 955          */
 956         function sock_to_host( $host ) {
 957                 if ( isset( $this->_cache_sock[$host] ) ) {
 958                         return $this->_cache_sock[$host];
 959                 }
 960
 961                 $sock = null;
 962                 $now = time();
 963                 list( $ip, /* $port */) = explode( ':', $host );
 964                 if ( isset( $this->_host_dead[$host] ) && $this->_host_dead[$host] > $now ||
 965                         isset( $this->_host_dead[$ip] ) && $this->_host_dead[$ip] > $now
 966                 ) {
 967                         return null;
 968                 }
 969
 970                 if ( !$this->_connect_sock( $sock, $host ) ) {
 971                         return $this->_dead_host( $host );
 972                 }
 973
 974                 // Do not buffer writes
 975                 stream_set_write_buffer( $sock, 0 );
 976
 977                 $this->_cache_sock[$host] = $sock;
 978
 979                 return $this->_cache_sock[$host];
 980         }
 981
 982         function _debugprint( $str ) {
 983                 print( $str );
 984         }
 985
 986         /**
 987          * Write to a stream, timing out after the correct amount of time
 988          *
 989          * @return bool false on failure, true on success
 990          */
 991         /*
 992         function _safe_fwrite( $f, $buf, $len = false ) {
 993                 stream_set_blocking( $f, 0 );
 994
 995                 if ( $len === false ) {
 996                         wfDebug( "Writing " . strlen( $buf ) . " bytes\n" );
 997                         $bytesWritten = fwrite( $f, $buf );
 998                 } else {
 999                         wfDebug( "Writing $len bytes\n" );
1000                         $bytesWritten = fwrite( $f, $buf, $len );
1001                 }
1002                 $n = stream_select( $r = null, $w = array( $f ), $e = null, 10, 0 );
1003                 #   $this->_timeout_seconds, $this->_timeout_microseconds );
1004
1005                 wfDebug( "stream_select returned $n\n" );
1006                 stream_set_blocking( $f, 1 );
1007                 return $n == 1;
1008                 return $bytesWritten;
1009         }*/
1010
1011         /**
1012          * Original behaviour
1013          */
1014         function _safe_fwrite( $f, $buf, $len = false ) {
1015                 if ( $len === false ) {
1016                         $bytesWritten = fwrite( $f, $buf );
1017                 } else {
1018                         $bytesWritten = fwrite( $f, $buf, $len );
1019                 }
1020                 return $bytesWritten;
1021         }
1022
1023         /**
1024          * Flush the read buffer of a stream
1025          */
1026         function _flush_read_buffer( $f ) {
1027                 if ( !is_resource( $f ) ) {
1028                         return;
1029                 }
1030                 $n = stream_select( $r = array( $f ), $w = null, $e = null, 0, 0 );
1031                 while ( $n == 1 && !feof( $f ) ) {
1032                         fread( $f, 1024 );
1033                         $n = stream_select( $r = array( $f ), $w = null, $e = null, 0, 0 );
1034                 }
1035         }
1036
1037         // }}}
1038         // }}}
1039         // }}}
1040 }
1041
1042 // vim: sts=3 sw=3 et
1043
1044 // }}}
1045
1046 class MemCachedClientforWiki extends MWMemcached {
1047         function _debugprint( $text ) {
1048                 wfDebug( "memcached: $text" );
1049         }
1050 }