[1] | 1 | <?php |
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| 2 | /** |
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[362] | 3 | * The Strangecode Codebase - a general application development framework for PHP |
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| 4 | * For details visit the project site: <http://trac.strangecode.com/codebase/> |
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[396] | 5 | * Copyright 2001-2012 Strangecode, LLC |
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[362] | 6 | * |
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| 7 | * This file is part of The Strangecode Codebase. |
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| 8 | * |
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| 9 | * The Strangecode Codebase is free software: you can redistribute it and/or |
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| 10 | * modify it under the terms of the GNU General Public License as published by the |
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| 11 | * Free Software Foundation, either version 3 of the License, or (at your option) |
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| 12 | * any later version. |
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| 13 | * |
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| 14 | * The Strangecode Codebase is distributed in the hope that it will be useful, but |
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| 15 | * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
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| 16 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more |
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| 17 | * details. |
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| 18 | * |
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| 19 | * You should have received a copy of the GNU General Public License along with |
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| 20 | * The Strangecode Codebase. If not, see <http://www.gnu.org/licenses/>. |
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| 21 | */ |
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| 22 | |
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| 23 | /** |
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[136] | 24 | * Cache.inc.php |
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| 25 | * |
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[1] | 26 | * Provides an API for storing a limited amount of data |
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| 27 | * intended to have a short lifetime in a user's session. |
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| 28 | * |
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| 29 | * @author Quinn Comendant <quinn@strangecode.com> |
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[136] | 30 | * @version 2.1 |
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[1] | 31 | * @since 2001 |
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| 32 | */ |
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[136] | 33 | |
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| 34 | // Flags. |
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[152] | 35 | define('CACHE_ALLOW_OVERSIZED', 1); |
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[136] | 36 | |
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| 37 | class Cache { |
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| 38 | |
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[152] | 39 | // Namespace of this instance of Prefs. |
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| 40 | var $_ns; |
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| 41 | |
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| 42 | // Configuration parameters for this object. |
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[1] | 43 | var $_params = array( |
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[152] | 44 | |
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[334] | 45 | // If false nothing will be cached or retrieved. Useful for testing realtime data requests. |
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[21] | 46 | 'enabled' => true, |
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[152] | 47 | |
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| 48 | // The maximum size in bytes of any one variable. |
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| 49 | 'item_size_limit' => 4194304, // 4 MB |
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| 50 | |
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| 51 | // The maximum size in bytes before the cache will begin flushing out old items. |
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| 52 | 'stack_size_limit' => 4194304, // 4 MB |
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| 53 | |
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| 54 | // The minimum items to keep in the cache regardless of item or cache size. |
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| 55 | 'min_items' => 5, |
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[1] | 56 | ); |
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[152] | 57 | |
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| 58 | /* |
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| 59 | * Constructor |
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| 60 | * |
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| 61 | * @access public |
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| 62 | * @param string $namespace This object will store data under this realm. |
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| 63 | * @author Quinn Comendant <quinn@strangecode.com> |
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| 64 | * @version 1.0 |
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| 65 | * @since 05 Jun 2006 23:14:21 |
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| 66 | */ |
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| 67 | function Cache($namespace='') |
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| 68 | { |
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[172] | 69 | $app =& App::getInstance(); |
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| 70 | |
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[154] | 71 | $this->_ns = $namespace; |
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[172] | 72 | |
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| 73 | if (true !== $app->getParam('enable_session')) { |
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[238] | 74 | $app->logMsg('Cache disabled, enable_session is false.', LOG_DEBUG, __FILE__, __LINE__); |
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[172] | 75 | $this->setParam(array('enabled' => false)); |
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| 76 | } |
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[152] | 77 | |
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[154] | 78 | if (!isset($_SESSION['_cache'][$this->_ns])) { |
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[152] | 79 | $this->clear(); |
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| 80 | } |
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| 81 | } |
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[1] | 82 | |
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| 83 | /** |
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| 84 | * This method enforces the singleton pattern for this class. |
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| 85 | * |
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[136] | 86 | * @return object Reference to the global Cache object. |
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[1] | 87 | * @access public |
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| 88 | * @static |
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| 89 | */ |
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[380] | 90 | static function &getInstance($namespace='') |
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[136] | 91 | { |
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[152] | 92 | static $instances = array(); |
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[1] | 93 | |
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[152] | 94 | if (!array_key_exists($namespace, $instances)) { |
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| 95 | $instances[$namespace] = new Cache($namespace); |
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[1] | 96 | } |
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| 97 | |
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[152] | 98 | return $instances[$namespace]; |
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[1] | 99 | } |
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| 100 | |
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| 101 | /** |
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| 102 | * Set (or overwrite existing) parameters by passing an array of new parameters. |
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| 103 | * |
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| 104 | * @access public |
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| 105 | * @param array $params Array of parameters (key => val pairs). |
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| 106 | */ |
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| 107 | function setParam($params) |
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| 108 | { |
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[136] | 109 | $app =& App::getInstance(); |
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[21] | 110 | |
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[1] | 111 | if (isset($params) && is_array($params)) { |
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| 112 | // Merge new parameters with old overriding only those passed. |
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[136] | 113 | $this->_params = array_merge($this->_params, $params); |
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[1] | 114 | } else { |
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[136] | 115 | $app->logMsg(sprintf('Parameters are not an array: %s', $params), LOG_ERR, __FILE__, __LINE__); |
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[1] | 116 | } |
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| 117 | } |
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| 118 | |
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| 119 | /** |
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| 120 | * Return the value of a parameter, if it exists. |
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| 121 | * |
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| 122 | * @access public |
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| 123 | * @param string $param Which parameter to return. |
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| 124 | * @return mixed Configured parameter value. |
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| 125 | */ |
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| 126 | function getParam($param) |
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| 127 | { |
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[136] | 128 | $app =& App::getInstance(); |
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| 129 | |
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| 130 | if (isset($this->_params[$param])) { |
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| 131 | return $this->_params[$param]; |
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[1] | 132 | } else { |
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[146] | 133 | $app->logMsg(sprintf('Parameter is not set: %s', $param), LOG_DEBUG, __FILE__, __LINE__); |
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[1] | 134 | return null; |
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| 135 | } |
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| 136 | } |
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| 137 | |
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| 138 | /** |
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[334] | 139 | * Stores a new variable in the session cache. The $key should not be numeric |
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[174] | 140 | * because the array_shift function will reset the key to the next largest |
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| 141 | * int key. Weird behavior I can't understand. For example $cache["123"] will become $cache[0] |
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[1] | 142 | * |
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[136] | 143 | * @param str $key An identifier for the cached object. |
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[152] | 144 | * @param mixed $var The var to store in the session cache. |
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[136] | 145 | * @param bool $flags If we have something really big that we |
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[152] | 146 | * still want to cache, setting this to |
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| 147 | * CACHE_ALLOW_OVERSIZED allows this. |
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| 148 | * @return bool True on success, false otherwise. |
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[1] | 149 | */ |
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[136] | 150 | function set($key, $var, $flags=0) |
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[1] | 151 | { |
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[136] | 152 | $app =& App::getInstance(); |
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[1] | 153 | |
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[152] | 154 | if (true !== $this->getParam('enabled')) { |
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[316] | 155 | $app->logMsg(sprintf('Cache disabled, not saving data.', null), LOG_DEBUG, __FILE__, __LINE__); |
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[21] | 156 | return false; |
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| 157 | } |
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| 158 | |
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[152] | 159 | $var = serialize($var); |
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[247] | 160 | $var_len = mb_strlen($var); |
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[42] | 161 | |
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[152] | 162 | if ($var_len >= $this->getParam('item_size_limit')) { |
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| 163 | $app->logMsg(sprintf('Serialized variable (%s bytes) more than item_size_limit (%s bytes).', $var_len, $this->getParam('item_size_limit')), LOG_NOTICE, __FILE__, __LINE__); |
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[1] | 164 | return false; |
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| 165 | } |
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[42] | 166 | |
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[152] | 167 | if ($flags & CACHE_ALLOW_OVERSIZED == 0 && $var_len >= $this->getParam('stack_size_limit')) { |
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| 168 | $app->logMsg(sprintf('Serialized variable (%s bytes) more than stack_size_limit (%s bytes).', $var_len, $this->getParam('stack_size_limit')), LOG_NOTICE, __FILE__, __LINE__); |
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[1] | 169 | return false; |
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[152] | 170 | } |
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[1] | 171 | |
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[152] | 172 | // Remove any value already stored under this key. |
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[174] | 173 | unset($_SESSION['_cache'][$this->_ns][$key]); |
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[152] | 174 | |
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| 175 | // Continue to prune the cache if its size is greater than stack_size_limit, but keep at least min_items. |
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[247] | 176 | while (mb_strlen(serialize($_SESSION['_cache'][$this->_ns])) + $var_len >= $this->getParam('stack_size_limit') && sizeof($_SESSION['_cache'][$this->_ns]) >= $this->getParam('min_items')) { |
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[154] | 177 | array_shift($_SESSION['_cache'][$this->_ns]); |
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[1] | 178 | } |
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[42] | 179 | |
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[152] | 180 | // Save this value under the specified key. |
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[174] | 181 | $_SESSION['_cache'][$this->_ns][$key] =& $var; |
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[152] | 182 | |
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| 183 | if ($var_len >= 1024000) { |
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| 184 | $app->logMsg(sprintf('Successfully cached oversized variable (%s bytes).', $var_len), LOG_DEBUG, __FILE__, __LINE__); |
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[1] | 185 | } |
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[42] | 186 | |
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[136] | 187 | return true; |
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[1] | 188 | } |
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[42] | 189 | |
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[1] | 190 | /** |
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[334] | 191 | * Retrieves an object from the session cache and returns it unserialized. |
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[1] | 192 | * It also moves it to the top of the stack, which makes it such that the |
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| 193 | * cache flushing mechanism of putCache deletes the oldest referenced items |
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| 194 | * first. |
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| 195 | * |
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[136] | 196 | * @param string $key The key for the datum to retrieve. |
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[1] | 197 | * @return mixed The requested datum, or false on failure. |
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| 198 | */ |
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[136] | 199 | function get($key) |
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[1] | 200 | { |
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[153] | 201 | $app =& App::getInstance(); |
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[162] | 202 | |
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[152] | 203 | if (true !== $this->getParam('enabled')) { |
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[316] | 204 | $app->logMsg(sprintf('Cache disabled, not getting data.', null), LOG_DEBUG, __FILE__, __LINE__); |
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[21] | 205 | return false; |
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| 206 | } |
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[42] | 207 | |
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[218] | 208 | if (array_key_exists($key, $_SESSION['_cache'][$this->_ns])) { |
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[153] | 209 | $app->logMsg(sprintf('Retreiving %s from cache.', $key), LOG_DEBUG, __FILE__, __LINE__); |
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[1] | 210 | // Move the accessed cached datum to the top of the stack. Maybe somebody knows a better way to do this? |
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[174] | 211 | $tmp =& $_SESSION['_cache'][$this->_ns][$key]; |
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| 212 | unset($_SESSION['_cache'][$this->_ns][$key]); |
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| 213 | $_SESSION['_cache'][$this->_ns][$key] =& $tmp; |
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[1] | 214 | // Return the unserialized datum. |
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[174] | 215 | return unserialize($_SESSION['_cache'][$this->_ns][$key]); |
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[1] | 216 | } else { |
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[172] | 217 | $app->logMsg(sprintf('Missing %s from cache.', $key), LOG_DEBUG, __FILE__, __LINE__); |
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[1] | 218 | return false; |
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| 219 | } |
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| 220 | } |
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[42] | 221 | |
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[1] | 222 | /** |
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| 223 | * Tells you if the object is cached. |
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| 224 | * |
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[136] | 225 | * @param string $key The key of the object to check. |
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[218] | 226 | * @return bool True if a value exists for the given key. |
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[1] | 227 | */ |
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[136] | 228 | function exists($key) |
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[1] | 229 | { |
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[405] | 230 | $app =& App::getInstance(); |
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| 231 | |
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[152] | 232 | if (true !== $this->getParam('enabled')) { |
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[405] | 233 | $app->logMsg(sprintf('Cache disabled on exist assertion.', null), LOG_DEBUG, __FILE__, __LINE__); |
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[21] | 234 | return false; |
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| 235 | } |
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| 236 | |
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[174] | 237 | return array_key_exists($key, $_SESSION['_cache'][$this->_ns]); |
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[1] | 238 | } |
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[42] | 239 | |
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[1] | 240 | /** |
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[188] | 241 | * Removes a cached object. |
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[1] | 242 | * |
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[136] | 243 | * @param string $key The key of the object to check. |
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[218] | 244 | * @return bool True if the value existed before being unset. |
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[1] | 245 | */ |
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[136] | 246 | function delete($key) |
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[1] | 247 | { |
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[218] | 248 | if (array_key_exists($key, $_SESSION['_cache'][$this->_ns])) { |
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| 249 | unset($_SESSION['_cache'][$this->_ns][$key]); |
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| 250 | return true; |
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| 251 | } else { |
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| 252 | return false; |
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| 253 | } |
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[1] | 254 | } |
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[152] | 255 | |
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| 256 | /* |
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| 257 | * Delete all existing items from the cache. |
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| 258 | * |
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| 259 | * @access public |
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| 260 | * @author Quinn Comendant <quinn@strangecode.com> |
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| 261 | * @version 1.0 |
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| 262 | * @since 05 Jun 2006 23:51:34 |
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| 263 | */ |
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| 264 | function clear() |
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| 265 | { |
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[154] | 266 | $_SESSION['_cache'][$this->_ns] = array(); |
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[152] | 267 | } |
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[1] | 268 | |
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[136] | 269 | // END Cache |
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[1] | 270 | } |
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| 271 | |
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| 272 | ?> |
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