3 * Per-process memory cache for storing items.
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
15 * You should have received a copy of the GNU General Public License along
16 * with this program; if not, write to the Free Software Foundation, Inc.,
17 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
18 * http://www.gnu.org/copyleft/gpl.html
25 * Handles per process caching of items
28 class ProcessCacheLRU
{
30 protected $cache = array(); // (key => prop => value)
32 protected $maxCacheKeys; // integer; max entries
35 * @param $maxKeys integer Maximum number of entries allowed (min 1).
36 * @throws MWException When $maxCacheKeys is not an int or =< 0.
38 public function __construct( $maxKeys ) {
39 if ( !is_int( $maxKeys ) ||
$maxKeys < 1 ) {
40 throw new MWException( __METHOD__
. " must be given an integer and >= 1" );
42 $this->maxCacheKeys
= $maxKeys;
46 * Set a property field for a cache entry.
47 * This will prune the cache if it gets too large.
48 * If the item is already set, it will be pushed to the top of the cache.
55 public function set( $key, $prop, $value ) {
56 if ( isset( $this->cache
[$key] ) ) {
57 $this->ping( $key ); // push to top
58 } elseif ( count( $this->cache
) >= $this->maxCacheKeys
) {
59 reset( $this->cache
);
60 unset( $this->cache
[key( $this->cache
)] );
62 $this->cache
[$key][$prop] = $value;
66 * Check if a property field exists for a cache entry.
72 public function has( $key, $prop ) {
73 return isset( $this->cache
[$key][$prop] );
77 * Get a property field for a cache entry.
78 * This returns null if the property is not set.
79 * If the item is already set, it will be pushed to the top of the cache.
85 public function get( $key, $prop ) {
86 if ( isset( $this->cache
[$key][$prop] ) ) {
87 $this->ping( $key ); // push to top
88 return $this->cache
[$key][$prop];
95 * Clear one or several cache entries, or all cache entries
97 * @param $keys string|Array
100 public function clear( $keys = null ) {
101 if ( $keys === null ) {
102 $this->cache
= array();
104 foreach ( (array)$keys as $key ) {
105 unset( $this->cache
[$key] );
111 * Push an entry to the top of the cache
115 protected function ping( $key ) {
116 $item = $this->cache
[$key];
117 unset( $this->cache
[$key] );
118 $this->cache
[$key] = $item;