/usr/share/php/Cache/Container/shm.php is in php-cache 1.5.6-2ubuntu1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 | <?php
// +----------------------------------------------------------------------+
// | PEAR :: Cache |
// +----------------------------------------------------------------------+
// | Copyright (c) 1997-2003 The PHP Group |
// +----------------------------------------------------------------------+
// | This source file is subject to version 2.0 of the PHP license, |
// | that is bundled with this package in the file LICENSE, and is |
// | available at through the world-wide-web at |
// | http://www.php.net/license/2_02.txt. |
// | If you did not receive a copy of the PHP license and are unable to |
// | obtain it through the world-wide-web, please send a note to |
// | license@php.net so we can mail you a copy immediately. |
// +----------------------------------------------------------------------+
// | Authors: Ulf Wendel <ulf.wendel@phpdoc.de> |
// | Sebastian Bergmann <sb@sebastian-bergmann.de> |
// +----------------------------------------------------------------------+
//
// $Id: shm.php 186977 2005-05-25 10:00:41Z dufuz $
require_once 'Cache/Container.php';
/**
* Stores cache data into shared memory.
*
* Well, this is not a very efficient implementation. Indeed it's much
* slower than the file container as far as my tests showed. Files are
* cached by most operating systems and it will be hard to write a faster
* caching algorithm using PHP.
*
* @author Ulf Wendel <ulf.wendel@phpdoc.de>
* @version $Id: shm.php 186977 2005-05-25 10:00:41Z dufuz $
* @package Cache
*/
class Cache_Container_shm extends Cache_Container
{
/**
* Key of the semaphore used to sync the SHM access
*
* @var int
*/
var $sem_key = null;
/**
* Permissions of the semaphore used to sync the SHM access
*
* @var int
*/
var $sem_perm = 0644;
/**
* Semaphore handler
*
* @var resource
*/
var $sem_id = null;
/**
* Key of the shared memory block used to store cache data
*
* @var int
*/
var $shm_key = null;
/**
* Size of the shared memory block used
*
* Note: the container does only use _one_ shm block no more!
*
* @var int
*/
var $shm_size = 131072;
/**
* Permissions of the shared memory block
*
* @var int
*/
var $shm_perm = 0644;
/**
* Shared memory handler
*
* @var resource
*/
var $shm_id = null;
/**
* Hash of cache entries
*
* Used by the garbage collection to find old entries.
*
* @var array
*/
var $entries = array();
/**
* Number of bytes consumed by the cache
*
* @var int
*/
var $total_size = 0;
/**
* Creates a shared memory container
*
* @param array shm_key, sem_key, shm_size, sem_perm, shm_perm
*/
function Cache_Container_shm($options = '')
{
if (is_array($options)) {
$this->setOptions($options, array_merge($this->allowed_options,
array('shm_key', 'sem_key',
'shm_size', 'sem_perm',
'shm_perm'
)
)
);
}
// Cache::Container high- and lowwater defaults should be overridden if
// not already done by the user
if (!isset($options['highwater'])) {
$this->highwater = round(0.75 * 131072);
}
if (!isset($options['lowwater'])) {
$this->lowwater = round(0.5 * 131072);
}
if (!isset($options['shm_size'])) {
$this->shm_size = 131072;
}
//get SHM and Semaphore handles
if (!($this->shm_id = shmop_open($this->shm_key, 'c', $this->shm_perm, $this->shm_size))) {
new Cache_Error("Can't open SHM segment '{$this->shm_key}', size '{$this->shm_size}'.",
__FILE__,
__LINE__
);
}
if (!($this->sem_id = sem_get($this->sem_key, 1, $this->sem_perm))) {
new Cache_Error("Can't get semaphore '{$this->sem_key}' using perms '{$this->sem_perm}'.",
__FILE__,
__LINE__
);
}
} // end constructor
function fetch($id, $group)
{
sem_acquire($this->sem_id);
$cachedata = shmop_read($this->shm_id, 0, $this->shm_size);
sem_release($this->sem_id);
$cachedata = $this->decode($cachedata);
if (!isset($cachedata[$group][$id])) {
return array(null, null, null);
} else {
$cachedata = $cachedata[$group][$id];
}
return array($cachedata['expire'],
$cachedata['cachedata'],
$cachedata['userdata']
);
} // end func fetch
function save($id, $data, $expire, $group, $userdata)
{
$this->flushPreload($id, $group);
sem_acquire($this->sem_id);
$cachedata = $this->decode(shmop_read($this->shm_id, 0, $this->shm_size));
$cachedata[$group][$id] = array('expire' => $this->getExpiresAbsolute($expire),
'cachedata' => $data,
'userdata' => $userdata,
'changed' => time()
);
if (strlen($newdata = $this->encode($cachedata)) > $this->shm_size) {
$cachedata = $this->garbageCollection(time(), $cachedata);
}
shmop_write($this->shm_id, $newdata, 0);
sem_release($this->sem_id);
return true;
} // end func save
function remove($id, $group)
{
$this->flushPreload($id, $group);
sem_acquire($this->sem_id);
$cachedata = $this->decode(shmop_read($this->shm_id, 0, $this->shm_size));
unset($cachedata[$group][$id]);
shmop_write($this->shm_id, $this->encode($cachedata), 0);
sem_release($this->sem_id);
} // end func remove
function flush($group = '')
{
$this->flushPreload();
sem_acquire($this->sem_id);
shmop_write($this->shm_id, $this->encode(array()), 0);
sem_release($this->sem_id);
} // end func flush
function idExists($id, $group)
{
sem_acquire($this->sem_id);
$cachedata = shm_read($this->shm_id, 0, $this->shm_size);
sem_release($this->sem_id);
$cachedata = $this->decode($cachedata);
return isset($cachedata[$group][$id]);
} // end func isExists
function garbageCollection($maxlifetime, $cachedata = array())
{
if ($lock = empty($cachedata)) {
sem_acquire($this->sem_id);
$cachedata = $this->decode(shmop_read($this->shm_id, 0, $this->shm_size));
}
$this->doGarbageCollection($maxlifetime, $cachedata);
if ($this->total_size > $this->highwater) {
krsort($this->entries);
reset($this->entries);
while ($this->total_size > $this->lowwater && list($size, $entries) = each($this->entries)) {
reset($entries);
while (list($k, $entry) = each($entries)) {
unset($cachedata[$entry['group']][$entry['id']]);
$this->total_size -= $size;
}
}
}
if ($lock) {
sem_release($this->sem_id);
}
$this->entries = array();
$this->total_size = 0;
return $cachedata;
} // end func garbageCollection
function doGarbageCollection($maxlifetime, &$cachedata)
{
$changed = time() - $maxlifetime;
$removed = 0;
reset($cachedata);
while (list($group, $groupdata) = each($cachedata)) {
reset($groupdata);
while (list($id, $data) = each($groupdata)) {
if ($data['expire'] < time() || $data['changed'] < $changed) {
unset($cachedata[$group][$id]);
}
}
// ugly but simple to implement :/
$size = strlen($this->encode($data));
$this->entries[$size][] = array(
'group' => $group,
'id' => $id
);
$this->total_size += $size;
}
return $removed;
} // end func doGarbageCollection
} // end class Cache_Container_shm
?>
|