File: include/core/WASHM.lib

<?php

/*
    WASHM.lib, DomCore, the WebAbility(r) Core System
    Contains the shared memory manager class to access resident memory variables
    (c) 2008-2012 Philippe Thomassigny

    This file is part of DomCore

    DomCore is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    DomCore is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with DomCore.  If not, see <http://www.gnu.org/licenses/>.
*/

/* @UML_Box -- Do not edit
|------------------------------------------------------------------|
| SHM : Shared Memory static object                                |
|------------------------------------------------------------------|
| - size : integer                                                 |
| - memid : integer                                                |
| - shm : resource                                                 |
|------------------------------------------------------------------|
| + new WASHM($size: integer, $memid: integer)                     |
| - start() : void                                                 |
| - attach() : resource                                            |
| - detach() : void                                                |
| - getlink($id: string, $type: enum(null, 'r', 'w', 'd')) : array('p': integer, 'r': timestamp, 'w': timestamp) |
| - writelink($id: string, $pointer: integer) : void               |
| - getnextpointer() : integer                                     |
| + write($id: string, $val: mixed) : void                         |
| + read($id: string) : void                                       |
| + delete($id: string) : void                                     |
| + lastread($id: string) : timestamp                              |
| + lastwrite($id: string) : timestamp                             |
| + __get($id: string) : mixed                                     |
| + __set($id: string, $data: mixed) : void                        |
| + __isset($id: string) : boolean                                 |
| + __unset($id: string) : void                                    |
| + flush() : void                                                 |
| + content() : array($name:string => $id: string)                 |
| + size() : array( 'total' => integer, 'used' => integer, 'free' => integer) |
|------------------------------------------------------------------|
|------------------------------------------------------------------|
@End_UML_Box */

class WASHM extends WADebug
{
  private $size = 20971520; // 20 MB by default (1024*1024*20)
  private $memid = 10010;   // our version by default, arbitrary value
  private $shm = null;      // our shared memory segment resource pointer

  public function __construct($size = null, $memid = null)
  {
    parent::__construct();

    if (self::$debug || $this->localdebug)
      $this->doDebug("include/core/WASHM->__construct( $size, $memid )", WADebug::SYSTEM);

    if (!function_exists('sem_get'))
      throw new SHMError(WAMessage::getMessage('WASHM.nosharedmemory'));

    if ($size)
      $this->size = $size;
    if ($memid)
      $this->memid = $memid;
    $this->start();
  }

  private function attach()
  {
    $this->shm = shm_attach($this->memid, $this->size);
    if (!$this->shm)
      throw new SHMError(WAMessage::getMessage('WASHM.noattach'));
  }

  private function detach()
  {
    shm_detach($this->shm);
    $this->shm = null;
  }

  private function start()
  {
    // check if we have availability of shared memory
    $this->attach();
    if (!shm_has_var($this->shm, 0))
    {
      shm_put_var($this->shm, 0, array());
      shm_put_var($this->shm, 1, 2);
    }
    $this->detach();
  }

  private function getlink($id, $type)
  {
    $links = shm_get_var($this->shm, 0);
    if (isset($links[$id]))
    {
      $link = $links[$id];
      if ($type == 'r') $links[$id]['r'] = microtime(true);
      if ($type == 'w') $links[$id]['w'] = microtime(true);
      if ($type == 'd') unset($links[$id]);
      if ($type)
        shm_put_var($this->shm, 0, $links);
      return $link;
    }
    return null;
  }

  private function writelink($id, $pointer)
  {
    $link = array('p' => $pointer, 'r' => null, 'w' => microtime(true));
    $links = shm_get_var($this->shm, 0);
    $links[$id] = $link;
    shm_put_var($this->shm, 0, $links);
  }

  private function getnextpointer()
  {
    $pt = shm_get_var($this->shm, 1);
    shm_put_var($this->shm, 1, $pt+1);
    return $pt;
  }

  // write an object into shm
  public function write($id, $data)
  {
    if (self::$debug || $this->localdebug)
      $this->doDebug("include/core/WASHM->write( $id, $data )", WADebug::SYSTEM);

    $this->attach();
    $link = $this->getlink($id, 'w');
    if ($link)
    {
      shm_put_var($this->shm, $link['p'], $data);
    }
    else
    {
      $pointer = $this->getnextpointer();
      shm_put_var($this->shm, $pointer, $data);
      $this->writelink($id, $pointer);
    }
    $this->detach();
  }

  // read an object from shm
  public function read($id)
  {
    if (self::$debug || $this->localdebug)
      $this->doDebug("include/core/WASHM->read( $id )", WADebug::SYSTEM);

    $this->attach();
    $var = null;
    $link = $this->getlink($id, 'r');
    if ($link)
      $var = shm_get_var($this->shm, $link['p']);
    $this->detach();
    return $var;
  }

  // delete an object from shm
  public function delete($id)
  {
    if (self::$debug || $this->localdebug)
      $this->doDebug("include/core/WASHM->delete( $id )", WADebug::SYSTEM);

    $this->attach();
    $link = $this->getlink($id, 'd');
    if ($link)
      $var = shm_remove_var($this->shm, $link['p']);
    $this->detach();
  }

  public function lastread($id)
  {
    if (self::$debug || $this->localdebug)
      $this->doDebug("include/core/WASHM->lastread( $id )", WADebug::SYSTEM);

    $this->attach();
    $link = $this->getlink($id, null);
    $this->detach();
    if ($link)
      return $link['r'];
    return null;
  }

  public function lastwrite($id)
  {
    if (self::$debug || $this->localdebug)
      $this->doDebug("include/core/WASHM->lastwrite( $id )", WADebug::SYSTEM);

    $this->attach();
    $link = $this->getlink($id, null);
    $this->detach();
    if ($link)
      return $link['w'];
    return null;
  }

  public function __get($id)
  {
    return $this->read($id);
  }

  public function __set($id, $data)
  {
    $this->write($id, $data);
  }

  public function __isset($id)
  {
    if (self::$debug || $this->localdebug)
      $this->doDebug("include/core/WASHM->__isset( $name )", WADebug::SYSTEM);

    $this->attach();
    $link = $this->getlink($id, null);
    $this->detach();
    return !!$link;
  }

  public function __unset($id)
  {
    $this->delete($id);
  }

  // clear all the memory
  public function flush()
  {
    if (self::$debug || $this->localdebug)
      $this->doDebug('include/core/WASHM->flush()', WADebug::SYSTEM);

    $this->attach();
    shm_remove($this->shm);
    $this->detach();
    //restart with same values
    $this->start();
  }

  // get all the id of sm objects
  public function content()
  {
    if (self::$debug || $this->localdebug)
      $this->doDebug('include/core/WASHM->content()', WADebug::SYSTEM);

    $this->attach();
    $links = shm_get_var($this->shm, 0);
    $this->detach();
    return $links;
  }

  // return totalmem, usedmem, freemem
  public function size()
  {
    if (self::$debug || $this->localdebug)
      $this->doDebug('include/core/WASHM->size()', WADebug::SYSTEM);

    $this->attach();
    // header size
    $size = (PHP_INT_SIZE * 4) + 8;
    $links = shm_get_var($this->shm, 0);
    $size += (((strlen(serialize($links))+ (4 * PHP_INT_SIZE)) /4 ) * 4 ) + 4;
    $pointer = shm_get_var($this->shm, 1);
    $size += (((strlen(serialize($pointer))+ (4 * PHP_INT_SIZE)) /4 ) * 4 ) + 4;
    foreach($links as $link)
    {
      $var = shm_get_var($this->shm, $link['p']);
      $size += (((strlen(serialize($var))+ (4 * PHP_INT_SIZE)) /4 ) * 4 ) + 4;
    }
    $this->detach();
    return array('total' => $this->size, 'used' => $size, 'free' => $this->size - $size);
  }

}

?>