<?php
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/**
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* @copyright Copyright (c) 2016, ownCloud, Inc.
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*
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* @author Robin Appelman <robin@icewind.nl>
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*
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* @license AGPL-3.0
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*
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* This code is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Affero General Public License, version 3,
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* as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Affero General Public License for more details.
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*
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* You should have received a copy of the GNU Affero General Public License, version 3,
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* along with this program. If not, see <http://www.gnu.org/licenses/>
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*
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*/
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namespace OC\Cache;
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use OCP\ICache;
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/**
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* In-memory cache with a capacity limit to keep memory usage in check
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*
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* Uses a simple FIFO expiry mechanism
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*/
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class CappedMemoryCache implements ICache, \ArrayAccess {
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private $capacity;
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private $cache = [];
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public function __construct($capacity = 512) {
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$this->capacity = $capacity;
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}
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public function hasKey($key) {
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return isset($this->cache[$key]);
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}
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public function get($key) {
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return isset($this->cache[$key]) ? $this->cache[$key] : null;
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}
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public function set($key, $value, $ttl = 0) {
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if (is_null($key)) {
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$this->cache[] = $value;
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} else {
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$this->cache[$key] = $value;
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}
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$this->garbageCollect();
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}
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public function remove($key) {
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unset($this->cache[$key]);
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return true;
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}
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public function clear($prefix = '') {
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$this->cache = [];
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return true;
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}
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public function offsetExists($offset) {
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return $this->hasKey($offset);
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}
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public function &offsetGet($offset) {
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return $this->cache[$offset];
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}
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public function offsetSet($offset, $value) {
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$this->set($offset, $value);
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}
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public function offsetUnset($offset) {
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$this->remove($offset);
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}
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public function getData() {
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return $this->cache;
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}
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private function garbageCollect() {
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while (count($this->cache) > $this->capacity) {
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reset($this->cache);
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$key = key($this->cache);
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$this->remove($key);
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}
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}
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}
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