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 memcached(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  * @package memcached-client
  61  * @version 0.1.2
  62  */
  63
  64 // {{{ requirements
  65 // }}}
  66
  67 // {{{ constants
  68 // {{{ flags
  69
  70 /**
  71  * Flag: indicates data is serialized
  72  */
  73 define("MEMCACHE_SERIALIZED", 1<<0);
  74
  75 /**
  76  * Flag: indicates data is compressed
  77  */
  78 define("MEMCACHE_COMPRESSED", 1<<1);
  79
  80 // }}}
  81
  82 /**
  83  * Minimum savings to store data compressed
  84  */
  85 define("COMPRESSION_SAVINGS", 0.20);
  86
  87 // }}}
  88
  89 // {{{ class memcached
  90 /**
  91  * memcached client class implemented using (p)fsockopen()
  92  *
  93  * @author  Ryan T. Dean <rtdean@cytherianage.net>
  94  * @addtogroup Cache
  95  */
  96 class memcached
  97 {
  98    // {{{ properties
  99    // {{{ public
 100
 101    /**
 102     * Command statistics
 103     *
 104     * @var     array
 105     * @access  public
 106     */
 107    var $stats;
 108
 109    // }}}
 110    // {{{ private
 111
 112    /**
 113     * Cached Sockets that are connected
 114     *
 115     * @var     array
 116     * @access  private
 117     */
 118    var $_cache_sock;
 119
 120    /**
 121     * Current debug status; 0 - none to 9 - profiling
 122     *
 123     * @var     boolean
 124     * @access  private
 125     */
 126    var $_debug;
 127
 128    /**
 129     * Dead hosts, assoc array, 'host'=>'unixtime when ok to check again'
 130     *
 131     * @var     array
 132     * @access  private
 133     */
 134    var $_host_dead;
 135
 136    /**
 137     * Is compression available?
 138     *
 139     * @var     boolean
 140     * @access  private
 141     */
 142    var $_have_zlib;
 143
 144    /**
 145     * Do we want to use compression?
 146     *
 147     * @var     boolean
 148     * @access  private
 149     */
 150    var $_compress_enable;
 151
 152    /**
 153     * At how many bytes should we compress?
 154     *
 155     * @var     integer
 156     * @access  private
 157     */
 158    var $_compress_threshold;
 159
 160    /**
 161     * Are we using persistant links?
 162     *
 163     * @var     boolean
 164     * @access  private
 165     */
 166    var $_persistant;
 167
 168    /**
 169     * If only using one server; contains ip:port to connect to
 170     *
 171     * @var     string
 172     * @access  private
 173     */
 174    var $_single_sock;
 175
 176    /**
 177     * Array containing ip:port or array(ip:port, weight)
 178     *
 179     * @var     array
 180     * @access  private
 181     */
 182    var $_servers;
 183
 184    /**
 185     * Our bit buckets
 186     *
 187     * @var     array
 188     * @access  private
 189     */
 190    var $_buckets;
 191
 192    /**
 193     * Total # of bit buckets we have
 194     *
 195     * @var     integer
 196     * @access  private
 197     */
 198    var $_bucketcount;
 199
 200    /**
 201     * # of total servers we have
 202     *
 203     * @var     integer
 204     * @access  private
 205     */
 206    var $_active;
 207
 208    /**
 209     * Stream timeout in seconds. Applies for example to fread()
 210     *
 211     * @var     integer
 212     * @access  private
 213     */
 214    var $_timeout_seconds;
 215
 216    /**
 217     * Stream timeout in microseconds
 218     *
 219     * @var     integer
 220     * @access  private
 221     */
 222    var $_timeout_microseconds;
 223
 224    /**
 225     * Connect timeout in seconds
 226     */
 227    var $_connect_timeout;
 228
 229    /**
 230     * Number of connection attempts for each server
 231     */
 232    var $_connect_attempts;
 233
 234    // }}}
 235    // }}}
 236    // {{{ methods
 237    // {{{ public functions
 238    // {{{ memcached()
 239
 240    /**
 241     * Memcache initializer
 242     *
 243     * @param   array    $args    Associative array of settings
 244     *
 245     * @return  mixed
 246     * @access  public
 247     */
 248    function memcached ($args)
 249    {
 250       $this->set_servers(@$args['servers']);
 251       $this->_debug = @$args['debug'];
 252       $this->stats = array();
 253       $this->_compress_threshold = @$args['compress_threshold'];
 254       $this->_persistant = array_key_exists('persistant', $args) ? (@$args['persistant']) : false;
 255       $this->_compress_enable = true;
 256       $this->_have_zlib = function_exists("gzcompress");
 257
 258       $this->_cache_sock = array();
 259       $this->_host_dead = array();
 260
 261       $this->_timeout_seconds = 1;
 262       $this->_timeout_microseconds = 0;
 263
 264       $this->_connect_timeout = 0.01;
 265       $this->_connect_attempts = 3;
 266    }
 267
 268    // }}}
 269    // {{{ add()
 270
 271    /**
 272     * Adds a key/value to the memcache server if one isn't already set with
 273     * that key
 274     *
 275     * @param   string  $key     Key to set with data
 276     * @param   mixed   $val     Value to store
 277     * @param   integer $exp     (optional) Time to expire data at
 278     *
 279     * @return  boolean
 280     * @access  public
 281     */
 282    function add ($key, $val, $exp = 0)
 283    {
 284       return $this->_set('add', $key, $val, $exp);
 285    }
 286
 287    // }}}
 288    // {{{ decr()
 289
 290    /**
 291     * Decriment a value stored on the memcache server
 292     *
 293     * @param   string   $key     Key to decriment
 294     * @param   integer  $amt     (optional) Amount to decriment
 295     *
 296     * @return  mixed    FALSE on failure, value on success
 297     * @access  public
 298     */
 299    function decr ($key, $amt=1)
 300    {
 301       return $this->_incrdecr('decr', $key, $amt);
 302    }
 303
 304    // }}}
 305    // {{{ delete()
 306
 307    /**
 308     * Deletes a key from the server, optionally after $time
 309     *
 310     * @param   string   $key     Key to delete
 311     * @param   integer  $time    (optional) How long to wait before deleting
 312     *
 313     * @return  boolean  TRUE on success, FALSE on failure
 314     * @access  public
 315     */
 316    function delete ($key, $time = 0)
 317    {
 318       if (!$this->_active)
 319          return false;
 320
 321       $sock = $this->get_sock($key);
 322       if (!is_resource($sock))
 323          return false;
 324
 325       $key = is_array($key) ? $key[1] : $key;
 326
 327       @$this->stats['delete']++;
 328       $cmd = "delete $key $time\r\n";
 329       if(!$this->_safe_fwrite($sock, $cmd, strlen($cmd)))
 330       {
 331          $this->_dead_sock($sock);
 332          return false;
 333       }
 334       $res = trim(fgets($sock));
 335
 336       if ($this->_debug)
 337          $this->_debugprint(sprintf("MemCache: delete %s (%s)\n", $key, $res));
 338
 339       if ($res == "DELETED")
 340          return true;
 341       return false;
 342    }
 343
 344    // }}}
 345    // {{{ disconnect_all()
 346
 347    /**
 348     * Disconnects all connected sockets
 349     *
 350     * @access  public
 351     */
 352    function disconnect_all ()
 353    {
 354       foreach ($this->_cache_sock as $sock)
 355          fclose($sock);
 356
 357       $this->_cache_sock = array();
 358    }
 359
 360    // }}}
 361    // {{{ enable_compress()
 362
 363    /**
 364     * Enable / Disable compression
 365     *
 366     * @param   boolean  $enable  TRUE to enable, FALSE to disable
 367     *
 368     * @access  public
 369     */
 370    function enable_compress ($enable)
 371    {
 372       $this->_compress_enable = $enable;
 373    }
 374
 375    // }}}
 376    // {{{ forget_dead_hosts()
 377
 378    /**
 379     * Forget about all of the dead hosts
 380     *
 381     * @access  public
 382     */
 383    function forget_dead_hosts ()
 384    {
 385       $this->_host_dead = array();
 386    }
 387
 388    // }}}
 389    // {{{ get()
 390
 391    /**
 392     * Retrieves the value associated with the key from the memcache server
 393     *
 394     * @param  string   $key     Key to retrieve
 395     *
 396     * @return  mixed
 397     * @access  public
 398     */
 399    function get ($key)
 400    {
 401       $fname = 'memcached::get';
 402       wfProfileIn( $fname );
 403
 404       if (!$this->_active) {
 405          wfProfileOut( $fname );
 406          return false;
 407       }
 408
 409       $sock = $this->get_sock($key);
 410
 411       if (!is_resource($sock)) {
 412          wfProfileOut( $fname );
 413          return false;
 414       }
 415
 416       @$this->stats['get']++;
 417
 418       $cmd = "get $key\r\n";
 419       if (!$this->_safe_fwrite($sock, $cmd, strlen($cmd)))
 420       {
 421          $this->_dead_sock($sock);
 422          wfProfileOut( $fname );
 423          return false;
 424       }
 425
 426       $val = array();
 427       $this->_load_items($sock, $val);
 428
 429       if ($this->_debug)
 430          foreach ($val as $k => $v)
 431             $this->_debugprint(@sprintf("MemCache: sock %s got %s => %s\r\n", serialize($sock), $k, $v));
 432
 433       wfProfileOut( $fname );
 434       return @$val[$key];
 435    }
 436
 437    // }}}
 438    // {{{ get_multi()
 439
 440    /**
 441     * Get multiple keys from the server(s)
 442     *
 443     * @param   array    $keys    Keys to retrieve
 444     *
 445     * @return  array
 446     * @access  public
 447     */
 448    function get_multi ($keys)
 449    {
 450       if (!$this->_active)
 451          return false;
 452
 453       $this->stats['get_multi']++;
 454       $sock_keys = array();
 455
 456       foreach ($keys as $key)
 457       {
 458          $sock = $this->get_sock($key);
 459          if (!is_resource($sock)) continue;
 460          $key = is_array($key) ? $key[1] : $key;
 461          if (!isset($sock_keys[$sock]))
 462          {
 463             $sock_keys[$sock] = array();
 464             $socks[] = $sock;
 465          }
 466          $sock_keys[$sock][] = $key;
 467       }
 468
 469       // Send out the requests
 470       foreach ($socks as $sock)
 471       {
 472          $cmd = "get";
 473          foreach ($sock_keys[$sock] as $key)
 474          {
 475             $cmd .= " ". $key;
 476          }
 477          $cmd .= "\r\n";
 478
 479          if ($this->_safe_fwrite($sock, $cmd, strlen($cmd)))
 480          {
 481             $gather[] = $sock;
 482          } else
 483          {
 484             $this->_dead_sock($sock);
 485          }
 486       }
 487
 488       // Parse responses
 489       $val = array();
 490       foreach ($gather as $sock)
 491       {
 492          $this->_load_items($sock, $val);
 493       }
 494
 495       if ($this->_debug)
 496          foreach ($val as $k => $v)
 497             $this->_debugprint(sprintf("MemCache: got %s => %s\r\n", $k, $v));
 498
 499       return $val;
 500    }
 501
 502    // }}}
 503    // {{{ incr()
 504
 505    /**
 506     * Increments $key (optionally) by $amt
 507     *
 508     * @param   string   $key     Key to increment
 509     * @param   integer  $amt     (optional) amount to increment
 510     *
 511     * @return  integer  New key value?
 512     * @access  public
 513     */
 514    function incr ($key, $amt=1)
 515    {
 516       return $this->_incrdecr('incr', $key, $amt);
 517    }
 518
 519    // }}}
 520    // {{{ replace()
 521
 522    /**
 523     * Overwrites an existing value for key; only works if key is already set
 524     *
 525     * @param   string   $key     Key to set value as
 526     * @param   mixed    $value   Value to store
 527     * @param   integer  $exp     (optional) Experiation time
 528     *
 529     * @return  boolean
 530     * @access  public
 531     */
 532    function replace ($key, $value, $exp=0)
 533    {
 534       return $this->_set('replace', $key, $value, $exp);
 535    }
 536
 537    // }}}
 538    // {{{ run_command()
 539
 540    /**
 541     * Passes through $cmd to the memcache server connected by $sock; returns
 542     * output as an array (null array if no output)
 543     *
 544     * NOTE: due to a possible bug in how PHP reads while using fgets(), each
 545     *       line may not be terminated by a \r\n.  More specifically, my testing
 546     *       has shown that, on FreeBSD at least, each line is terminated only
 547     *       with a \n.  This is with the PHP flag auto_detect_line_endings set
 548     *       to falase (the default).
 549     *
 550     * @param   resource $sock    Socket to send command on
 551     * @param   string   $cmd     Command to run
 552     *
 553     * @return  array    Output array
 554     * @access  public
 555     */
 556    function run_command ($sock, $cmd)
 557    {
 558       if (!is_resource($sock))
 559          return array();
 560
 561       if (!$this->_safe_fwrite($sock, $cmd, strlen($cmd)))
 562          return array();
 563
 564       while (true)
 565       {
 566          $res = fgets($sock);
 567          $ret[] = $res;
 568          if (preg_match('/^END/', $res))
 569             break;
 570          if (strlen($res) == 0)
 571             break;
 572       }
 573       return $ret;
 574    }
 575
 576    // }}}
 577    // {{{ set()
 578
 579    /**
 580     * Unconditionally sets a key to a given value in the memcache.  Returns true
 581     * if set successfully.
 582     *
 583     * @param   string   $key     Key to set value as
 584     * @param   mixed    $value   Value to set
 585     * @param   integer  $exp     (optional) Experiation time
 586     *
 587     * @return  boolean  TRUE on success
 588     * @access  public
 589     */
 590    function set ($key, $value, $exp=0)
 591    {
 592       return $this->_set('set', $key, $value, $exp);
 593    }
 594
 595    // }}}
 596    // {{{ set_compress_threshold()
 597
 598    /**
 599     * Sets the compression threshold
 600     *
 601     * @param   integer  $thresh  Threshold to compress if larger than
 602     *
 603     * @access  public
 604     */
 605    function set_compress_threshold ($thresh)
 606    {
 607       $this->_compress_threshold = $thresh;
 608    }
 609
 610    // }}}
 611    // {{{ set_debug()
 612
 613    /**
 614     * Sets the debug flag
 615     *
 616     * @param   boolean  $dbg     TRUE for debugging, FALSE otherwise
 617     *
 618     * @access  public
 619     *
 620     * @see     memcahced::memcached
 621     */
 622    function set_debug ($dbg)
 623    {
 624       $this->_debug = $dbg;
 625    }
 626
 627    // }}}
 628    // {{{ set_servers()
 629
 630    /**
 631     * Sets the server list to distribute key gets and puts between
 632     *
 633     * @param   array    $list    Array of servers to connect to
 634     *
 635     * @access  public
 636     *
 637     * @see     memcached::memcached()
 638     */
 639    function set_servers ($list)
 640    {
 641       $this->_servers = $list;
 642       $this->_active = count($list);
 643       $this->_buckets = null;
 644       $this->_bucketcount = 0;
 645
 646       $this->_single_sock = null;
 647       if ($this->_active == 1)
 648          $this->_single_sock = $this->_servers[0];
 649    }
 650
 651    /**
 652     * Sets the timeout for new connections
 653     *
 654     * @param   integer  $seconds Number of seconds
 655     * @param   integer  $microseconds  Number of microseconds
 656     *
 657     * @access  public
 658     */
 659    function set_timeout ($seconds, $microseconds)
 660    {
 661       $this->_timeout_seconds = $seconds;
 662       $this->_timeout_microseconds = $microseconds;
 663    }
 664
 665    // }}}
 666    // }}}
 667    // {{{ private methods
 668    // {{{ _close_sock()
 669
 670    /**
 671     * Close the specified socket
 672     *
 673     * @param   string   $sock    Socket to close
 674     *
 675     * @access  private
 676     */
 677    function _close_sock ($sock)
 678    {
 679       $host = array_search($sock, $this->_cache_sock);
 680       fclose($this->_cache_sock[$host]);
 681       unset($this->_cache_sock[$host]);
 682    }
 683
 684    // }}}
 685    // {{{ _connect_sock()
 686
 687    /**
 688     * Connects $sock to $host, timing out after $timeout
 689     *
 690     * @param   integer  $sock    Socket to connect
 691     * @param   string   $host    Host:IP to connect to
 692     *
 693     * @return  boolean
 694     * @access  private
 695     */
 696    function _connect_sock (&$sock, $host)
 697    {
 698       list ($ip, $port) = explode(":", $host);
 699       $sock = false;
 700       $timeout = $this->_connect_timeout;
 701       $errno = $errstr = null;
 702       for ($i = 0; !$sock && $i < $this->_connect_attempts; $i++) {
 703          if ($i > 0) {
 704             # Sleep until the timeout, in case it failed fast
 705             $elapsed = microtime(true) - $t;
 706             if ( $elapsed < $timeout ) {
 707                usleep(($timeout - $elapsed) * 1e6);
 708             }
 709             $timeout *= 2;
 710          }
 711          $t = microtime(true);
 712          if ($this->_persistant == 1)
 713          {
 714             $sock = @pfsockopen($ip, $port, $errno, $errstr, $timeout);
 715          } else
 716          {
 717             $sock = @fsockopen($ip, $port, $errno, $errstr, $timeout);
 718          }
 719       }
 720       if (!$sock) {
 721          if ($this->_debug)
 722             $this->_debugprint( "Error connecting to $host: $errstr\n" );
 723          return false;
 724       }
 725
 726       // Initialise timeout
 727       stream_set_timeout($sock, $this->_timeout_seconds, $this->_timeout_microseconds);
 728
 729       return true;
 730    }
 731
 732    // }}}
 733    // {{{ _dead_sock()
 734
 735    /**
 736     * Marks a host as dead until 30-40 seconds in the future
 737     *
 738     * @param   string   $sock    Socket to mark as dead
 739     *
 740     * @access  private
 741     */
 742    function _dead_sock ($sock)
 743    {
 744       $host = array_search($sock, $this->_cache_sock);
 745       @list ($ip, /* $port */) = explode(":", $host);
 746       $this->_host_dead[$ip] = time() + 30 + intval(rand(0, 10));
 747       $this->_host_dead[$host] = $this->_host_dead[$ip];
 748       unset($this->_cache_sock[$host]);
 749    }
 750
 751    // }}}
 752    // {{{ get_sock()
 753
 754    /**
 755     * get_sock
 756     *
 757     * @param   string   $key     Key to retrieve value for;
 758     *
 759     * @return  mixed    resource on success, false on failure
 760     * @access  private
 761     */
 762    function get_sock ($key)
 763    {
 764       if (!$this->_active)
 765          return false;
 766
 767       if ($this->_single_sock !== null) {
 768          $this->_flush_read_buffer($this->_single_sock);
 769          return $this->sock_to_host($this->_single_sock);
 770       }
 771
 772       $hv = is_array($key) ? intval($key[0]) : $this->_hashfunc($key);
 773
 774       if ($this->_buckets === null)
 775       {
 776          foreach ($this->_servers as $v)
 777          {
 778             if (is_array($v))
 779             {
 780                for ($i=0; $i<$v[1]; $i++)
 781                   $bu[] = $v[0];
 782             } else
 783             {
 784                $bu[] = $v;
 785             }
 786          }
 787          $this->_buckets = $bu;
 788          $this->_bucketcount = count($bu);
 789       }
 790
 791       $realkey = is_array($key) ? $key[1] : $key;
 792       for ($tries = 0; $tries<20; $tries++)
 793       {
 794          $host = $this->_buckets[$hv % $this->_bucketcount];
 795          $sock = $this->sock_to_host($host);
 796          if (is_resource($sock)) {
 797             $this->_flush_read_buffer($sock);
 798             return $sock;
 799          }
 800          $hv += $this->_hashfunc($tries . $realkey);
 801       }
 802
 803       return false;
 804    }
 805
 806    // }}}
 807    // {{{ _hashfunc()
 808
 809    /**
 810     * Creates a hash integer  based on the $key
 811     *
 812     * @param   string   $key     Key to hash
 813     *
 814     * @return  integer  Hash value
 815     * @access  private
 816     */
 817    function _hashfunc ($key)
 818    {
 819       # Hash function must on [0,0x7ffffff]
 820       # We take the first 31 bits of the MD5 hash, which unlike the hash
 821       # function used in a previous version of this client, works
 822       return hexdec(substr(md5($key),0,8)) & 0x7fffffff;
 823    }
 824
 825    // }}}
 826    // {{{ _incrdecr()
 827
 828    /**
 829     * Perform increment/decriment on $key
 830     *
 831     * @param   string   $cmd     Command to perform
 832     * @param   string   $key     Key to perform it on
 833     * @param   integer  $amt     Amount to adjust
 834     *
 835     * @return  integer     New value of $key
 836     * @access  private
 837     */
 838    function _incrdecr ($cmd, $key, $amt=1)
 839    {
 840       if (!$this->_active)
 841          return null;
 842
 843       $sock = $this->get_sock($key);
 844       if (!is_resource($sock))
 845          return null;
 846
 847       $key = is_array($key) ? $key[1] : $key;
 848       @$this->stats[$cmd]++;
 849       if (!$this->_safe_fwrite($sock, "$cmd $key $amt\r\n"))
 850          return $this->_dead_sock($sock);
 851
 852       stream_set_timeout($sock, 1, 0);
 853       $line = fgets($sock);
 854       $match = array();
 855       if (!preg_match('/^(\d+)/', $line, $match))
 856          return null;
 857       return $match[1];
 858    }
 859
 860    // }}}
 861    // {{{ _load_items()
 862
 863    /**
 864     * Load items into $ret from $sock
 865     *
 866     * @param   resource $sock    Socket to read from
 867     * @param   array    $ret     Returned values
 868     *
 869     * @access  private
 870     */
 871    function _load_items ($sock, &$ret)
 872    {
 873       while (1)
 874       {
 875          $decl = fgets($sock);
 876          if ($decl == "END\r\n")
 877          {
 878             return true;
 879          } elseif (preg_match('/^VALUE (\S+) (\d+) (\d+)\r\n$/', $decl, $match))
 880          {
 881             list($rkey, $flags, $len) = array($match[1], $match[2], $match[3]);
 882             $bneed = $len+2;
 883             $offset = 0;
 884
 885             while ($bneed > 0)
 886             {
 887                $data = fread($sock, $bneed);
 888                $n = strlen($data);
 889                if ($n == 0)
 890                   break;
 891                $offset += $n;
 892                $bneed -= $n;
 893                @$ret[$rkey] .= $data;
 894             }
 895
 896             if ($offset != $len+2)
 897             {
 898                // Something is borked!
 899                if ($this->_debug)
 900                   $this->_debugprint(sprintf("Something is borked!  key %s expecting %d got %d length\n", $rkey, $len+2, $offset));
 901
 902                unset($ret[$rkey]);
 903                $this->_close_sock($sock);
 904                return false;
 905             }
 906
 907             if ($this->_have_zlib && $flags & MEMCACHE_COMPRESSED)
 908                $ret[$rkey] = gzuncompress($ret[$rkey]);
 909
 910             $ret[$rkey] = rtrim($ret[$rkey]);
 911
 912             if ($flags & MEMCACHE_SERIALIZED)
 913                $ret[$rkey] = unserialize($ret[$rkey]);
 914
 915          } else
 916          {
 917             $this->_debugprint("Error parsing memcached response\n");
 918             return 0;
 919          }
 920       }
 921    }
 922
 923    // }}}
 924    // {{{ _set()
 925
 926    /**
 927     * Performs the requested storage operation to the memcache server
 928     *
 929     * @param   string   $cmd     Command to perform
 930     * @param   string   $key     Key to act on
 931     * @param   mixed    $val     What we need to store
 932     * @param   integer  $exp     When it should expire
 933     *
 934     * @return  boolean
 935     * @access  private
 936     */
 937    function _set ($cmd, $key, $val, $exp)
 938    {
 939       if (!$this->_active)
 940          return false;
 941
 942       $sock = $this->get_sock($key);
 943       if (!is_resource($sock))
 944          return false;
 945
 946       @$this->stats[$cmd]++;
 947
 948       $flags = 0;
 949
 950       if (!is_scalar($val))
 951       {
 952          $val = serialize($val);
 953          $flags |= MEMCACHE_SERIALIZED;
 954          if ($this->_debug)
 955             $this->_debugprint(sprintf("client: serializing data as it is not scalar\n"));
 956       }
 957
 958       $len = strlen($val);
 959
 960       if ($this->_have_zlib && $this->_compress_enable &&
 961           $this->_compress_threshold && $len >= $this->_compress_threshold)
 962       {
 963          $c_val = gzcompress($val, 9);
 964          $c_len = strlen($c_val);
 965
 966          if ($c_len < $len*(1 - COMPRESSION_SAVINGS))
 967          {
 968             if ($this->_debug)
 969                $this->_debugprint(sprintf("client: compressing data; was %d bytes is now %d bytes\n", $len, $c_len));
 970             $val = $c_val;
 971             $len = $c_len;
 972             $flags |= MEMCACHE_COMPRESSED;
 973          }
 974       }
 975       if (!$this->_safe_fwrite($sock, "$cmd $key $flags $exp $len\r\n$val\r\n"))
 976          return $this->_dead_sock($sock);
 977
 978       $line = trim(fgets($sock));
 979
 980       if ($this->_debug)
 981       {
 982          if ($flags & MEMCACHE_COMPRESSED)
 983             $val = 'compressed data';
 984          $this->_debugprint(sprintf("MemCache: %s %s => %s (%s)\n", $cmd, $key, $val, $line));
 985       }
 986       if ($line == "STORED")
 987          return true;
 988       return false;
 989    }
 990
 991    // }}}
 992    // {{{ sock_to_host()
 993
 994    /**
 995     * Returns the socket for the host
 996     *
 997     * @param   string   $host    Host:IP to get socket for
 998     *
 999     * @return  mixed    IO Stream or false
1000     * @access  private
1001     */
1002    function sock_to_host ($host)
1003    {
1004       if (isset($this->_cache_sock[$host]))
1005          return $this->_cache_sock[$host];
1006
1007       $sock = null;
1008       $now = time();
1009       list ($ip, /* $port */) = explode (":", $host);
1010       if (isset($this->_host_dead[$host]) && $this->_host_dead[$host] > $now ||
1011           isset($this->_host_dead[$ip]) && $this->_host_dead[$ip] > $now)
1012          return null;
1013
1014       if (!$this->_connect_sock($sock, $host))
1015          return $this->_dead_sock($host);
1016
1017       // Do not buffer writes
1018       stream_set_write_buffer($sock, 0);
1019
1020       $this->_cache_sock[$host] = $sock;
1021
1022       return $this->_cache_sock[$host];
1023    }
1024
1025    function _debugprint($str){
1026       print($str);
1027    }
1028
1029    /**
1030     * Write to a stream, timing out after the correct amount of time
1031     *
1032     * @return bool false on failure, true on success
1033     */
1034     /*
1035    function _safe_fwrite($f, $buf, $len = false) {
1036       stream_set_blocking($f, 0);
1037
1038       if ($len === false) {
1039          wfDebug("Writing " . strlen( $buf ) . " bytes\n");
1040          $bytesWritten = fwrite($f, $buf);
1041       } else {
1042          wfDebug("Writing $len bytes\n");
1043          $bytesWritten = fwrite($f, $buf, $len);
1044       }
1045       $n = stream_select($r=NULL, $w = array($f), $e = NULL, 10, 0);
1046       #   $this->_timeout_seconds, $this->_timeout_microseconds);
1047
1048       wfDebug("stream_select returned $n\n");
1049       stream_set_blocking($f, 1);
1050       return $n == 1;
1051       return $bytesWritten;
1052    }*/
1053
1054    /**
1055     * Original behaviour
1056     */
1057    function _safe_fwrite($f, $buf, $len = false) {
1058       if ($len === false) {
1059          $bytesWritten = fwrite($f, $buf);
1060       } else {
1061          $bytesWritten = fwrite($f, $buf, $len);
1062       }
1063       return $bytesWritten;
1064    }
1065
1066    /**
1067     * Flush the read buffer of a stream
1068     */
1069    function _flush_read_buffer($f) {
1070       if (!is_resource($f)) {
1071          return;
1072       }
1073       $n = stream_select($r=array($f), $w = NULL, $e = NULL, 0, 0);
1074       while ($n == 1 && !feof($f)) {
1075          fread($f, 1024);
1076          $n = stream_select($r=array($f), $w = NULL, $e = NULL, 0, 0);
1077       }
1078    }
1079
1080    // }}}
1081    // }}}
1082    // }}}
1083 }
1084
1085 // vim: sts=3 sw=3 et
1086
1087 // }}}
1088