Duplicate code is one of the most pungent code smells. A rule that is often used is to re-structure code once it is duplicated in three or more places.
Common duplication problems, and corresponding solutions are:
Complex classes like references_Cache_Lite often do a lot of different things. To break such a class down, we need to identify a cohesive component within that class. A common approach to find such a component is to look for fields/methods that share the same prefixes, or suffixes. You can also have a look at the cohesion graph to spot any un-connected, or weakly-connected components.
Once you have determined the fields that belong together, you can apply the Extract Class refactoring. If the component makes sense as a sub-class, Extract Subclass is also a candidate, and is often faster.
While breaking up the class, it is a good idea to analyze how other classes use references_Cache_Lite, and based on these observations, apply Extract Interface, too.
| 1 | <?php |
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| 28 | class references_Cache_Lite |
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| 29 | { |
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| 30 | |||
| 31 | // --- Private properties --- |
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| 32 | |||
| 33 | /** |
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| 34 | * Directory where to put the cache files |
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| 35 | * (make sure to add a trailing slash) |
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| 36 | * |
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| 37 | * @var string $_cacheDir |
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| 38 | */ |
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| 39 | public $_cacheDir = '/tmp/'; |
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| 40 | |||
| 41 | /** |
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| 42 | * Enable / disable caching |
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| 43 | * |
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| 44 | * (can be very usefull for the debug of cached scripts) |
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| 45 | * |
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| 46 | * @var boolean $_caching |
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| 47 | */ |
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| 48 | public $_caching = true; |
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| 49 | |||
| 50 | /** |
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| 51 | * Cache lifetime (in seconds) |
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| 52 | * |
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| 53 | * If null, the cache is valid forever. |
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| 54 | * |
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| 55 | * @var int $_lifeTime |
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| 56 | */ |
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| 57 | public $_lifeTime = 3600; |
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| 58 | |||
| 59 | /** |
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| 60 | * Enable / disable fileLocking |
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| 61 | * |
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| 62 | * (can avoid cache corruption under bad circumstances) |
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| 63 | * |
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| 64 | * @var boolean $_fileLocking |
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| 65 | */ |
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| 66 | public $_fileLocking = true; |
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| 67 | |||
| 68 | /** |
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| 69 | * Timestamp of the last valid cache |
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| 70 | * |
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| 71 | * @var int $_refreshTime |
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| 72 | */ |
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| 73 | public $_refreshTime; |
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| 74 | |||
| 75 | /** |
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| 76 | * File name (with path) |
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| 77 | * |
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| 78 | * @var string $_file |
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| 79 | */ |
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| 80 | public $_file; |
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| 81 | |||
| 82 | /** |
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| 83 | * File name (without path) |
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| 84 | * |
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| 85 | * @var string $_fileName |
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| 86 | */ |
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| 87 | public $_fileName; |
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| 88 | |||
| 89 | /** |
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| 90 | * Enable / disable write control (the cache is read just after writing to detect corrupt entries) |
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| 91 | * |
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| 92 | * Enable write control will lightly slow the cache writing but not the cache reading |
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| 93 | * Write control can detect some corrupt cache files but maybe it's not a perfect control |
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| 94 | * |
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| 95 | * @var boolean $_writeControl |
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| 96 | */ |
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| 97 | public $_writeControl = true; |
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| 98 | |||
| 99 | /** |
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| 100 | * Enable / disable read control |
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| 101 | * |
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| 102 | * If enabled, a control key is embeded in cache file and this key is compared with the one |
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| 103 | * calculated after the reading. |
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| 104 | * |
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| 105 | * @var boolean $_writeControl |
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| 106 | */ |
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| 107 | public $_readControl = true; |
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| 108 | |||
| 109 | /** |
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| 110 | * Type of read control (only if read control is enabled) |
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| 111 | * |
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| 112 | * Available values are : |
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| 113 | * 'md5' for a md5 hash control (best but slowest) |
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| 114 | * 'crc32' for a crc32 hash control (lightly less safe but faster, better choice) |
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| 115 | * 'strlen' for a length only test (fastest) |
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| 116 | * |
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| 117 | * @var boolean $_readControlType |
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| 118 | */ |
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| 119 | public $_readControlType = 'crc32'; |
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| 120 | |||
| 121 | /** |
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| 122 | * Pear error mode (when raiseError is called) |
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| 123 | * |
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| 124 | * (see PEAR doc) |
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| 125 | * |
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| 126 | * @see setToDebug() |
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| 127 | * @var int $_pearErrorMode |
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| 128 | */ |
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| 129 | public $_pearErrorMode = REFERENCES_CACHE_LITE_ERROR_RETURN; |
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| 130 | |||
| 131 | /** |
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| 132 | * Current cache id |
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| 133 | * |
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| 134 | * @var string $_id |
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| 135 | */ |
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| 136 | public $_id; |
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| 137 | |||
| 138 | /** |
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| 139 | * Current cache group |
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| 140 | * |
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| 141 | * @var string $_group |
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| 142 | */ |
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| 143 | public $_group; |
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| 144 | |||
| 145 | /** |
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| 146 | * Enable / Disable "Memory Caching" |
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| 147 | * |
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| 148 | * NB : There is no lifetime for memory caching ! |
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| 149 | * |
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| 150 | * @var boolean $_memoryCaching |
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| 151 | */ |
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| 152 | public $_memoryCaching = false; |
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| 153 | |||
| 154 | /** |
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| 155 | * Enable / Disable "Only Memory Caching" |
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| 156 | * (be carefull, memory caching is "beta quality") |
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| 157 | * |
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| 158 | * @var boolean $_onlyMemoryCaching |
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| 159 | */ |
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| 160 | public $_onlyMemoryCaching = false; |
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| 161 | |||
| 162 | /** |
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| 163 | * Memory caching array |
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| 164 | * |
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| 165 | * @var array $_memoryCachingArray |
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| 166 | */ |
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| 167 | public $_memoryCachingArray = array(); |
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| 168 | |||
| 169 | /** |
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| 170 | * Memory caching counter |
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| 171 | * |
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| 172 | * @var int $memoryCachingCounter |
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| 173 | */ |
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| 174 | public $_memoryCachingCounter = 0; |
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| 175 | |||
| 176 | /** |
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| 177 | * Memory caching limit |
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| 178 | * |
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| 179 | * @var int $memoryCachingLimit |
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| 180 | */ |
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| 181 | public $_memoryCachingLimit = 1000; |
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| 182 | |||
| 183 | /** |
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| 184 | * File Name protection |
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| 185 | * |
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| 186 | * if set to true, you can use any cache id or group name |
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| 187 | * if set to false, it can be faster but cache ids and group names |
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| 188 | * will be used directly in cache file names so be carefull with |
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| 189 | * special characters... |
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| 190 | * |
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| 191 | * @var boolean $fileNameProtection |
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| 192 | */ |
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| 193 | public $_fileNameProtection = true; |
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| 194 | |||
| 195 | /** |
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| 196 | * Enable / disable automatic serialization |
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| 197 | * |
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| 198 | * it can be used to save directly datas which aren't strings |
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| 199 | * (but it's slower) |
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| 200 | * |
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| 201 | * @var boolean $_serialize |
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| 202 | */ |
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| 203 | public $_automaticSerialization = false; |
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| 204 | |||
| 205 | /** |
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| 206 | * Disable / Tune the automatic cleaning process |
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| 207 | * |
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| 208 | * The automatic cleaning process destroy too old (for the given life time) |
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| 209 | * cache files when a new cache file is written. |
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| 210 | * 0 => no automatic cache cleaning |
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| 211 | * 1 => systematic cache cleaning |
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| 212 | * x (integer) > 1 => automatic cleaning randomly 1 times on x cache write |
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| 213 | * |
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| 214 | * @var int $_automaticCleaning |
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| 215 | */ |
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| 216 | public $_automaticCleaningFactor = 0; |
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| 217 | |||
| 218 | /** |
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| 219 | * Nested directory level |
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| 220 | * |
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| 221 | * Set the hashed directory structure level. 0 means "no hashed directory |
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| 222 | * structure", 1 means "one level of directory", 2 means "two levels"... |
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| 223 | * This option can speed up Cache_Lite only when you have many thousands of |
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| 224 | * cache file. Only specific benchs can help you to choose the perfect value |
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| 225 | * for you. Maybe, 1 or 2 is a good start. |
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| 226 | * |
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| 227 | * @var int $_hashedDirectoryLevel |
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| 228 | */ |
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| 229 | public $_hashedDirectoryLevel = 0; |
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| 230 | |||
| 231 | /** |
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| 232 | * Umask for hashed directory structure |
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| 233 | * |
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| 234 | * @var int $_hashedDirectoryUmask |
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| 235 | */ |
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| 236 | public $_hashedDirectoryUmask = 0700; |
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| 237 | |||
| 238 | /** |
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| 239 | * API break for error handling in REFERENCES_CACHE_LITE_ERROR_RETURN mode |
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| 240 | * |
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| 241 | * In REFERENCES_CACHE_LITE_ERROR_RETURN mode, error handling was not good because |
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| 242 | * for example save() method always returned a boolean (a PEAR_Error object |
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| 243 | * would be better in REFERENCES_CACHE_LITE_ERROR_RETURN mode). To correct this without |
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| 244 | * breaking the API, this option (false by default) can change this handling. |
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| 245 | * |
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| 246 | * @var boolean |
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| 247 | */ |
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| 248 | public $_errorHandlingAPIBreak = false; |
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| 249 | |||
| 250 | // --- Public methods --- |
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| 251 | |||
| 252 | /** |
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| 253 | * Constructor |
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| 254 | * |
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| 255 | * $options is an assoc. Available options are : |
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| 256 | * $options = array( |
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| 257 | * 'cacheDir' => directory where to put the cache files (string) , |
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| 258 | * 'caching' => enable / disable caching (boolean) , |
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| 259 | * 'lifeTime' => cache lifetime in seconds (int) , |
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| 260 | * 'fileLocking' => enable / disable fileLocking (boolean) , |
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| 261 | * 'writeControl' => enable / disable write control (boolean) , |
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| 262 | * 'readControl' => enable / disable read control (boolean) , |
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| 263 | * 'readControlType' => type of read control 'crc32', 'md5', 'strlen' (string) , |
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| 264 | * 'pearErrorMode' => pear error mode (when raiseError is called) (cf PEAR doc) (int) , |
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| 265 | * 'memoryCaching' => enable / disable memory caching (boolean) , |
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| 266 | * 'onlyMemoryCaching' => enable / disable only memory caching (boolean) , |
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| 267 | * 'memoryCachingLimit' => max nbr of records to store into memory caching (int) , |
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| 268 | * 'fileNameProtection' => enable / disable automatic file name protection (boolean) , |
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| 269 | * 'automaticSerialization' => enable / disable automatic serialization (boolean) , |
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| 270 | * 'automaticCleaningFactor' => distable / tune automatic cleaning process (int) , |
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| 271 | * 'hashedDirectoryLevel' => level of the hashed directory system (int) , |
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| 272 | * 'hashedDirectoryUmask' => umask for hashed directory structure (int) , |
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| 273 | * 'errorHandlingAPIBreak' => API break for better error handling ? (boolean) |
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| 274 | * ); |
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| 275 | * |
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| 276 | * @param array $options options |
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| 277 | * @access public |
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| 278 | */ |
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| 279 | public function __construct($options = array(null)) |
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| 285 | |||
| 286 | /** |
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| 287 | * Generic way to set a Cache_Lite option |
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| 288 | * |
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| 289 | * see Cache_Lite constructor for available options |
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| 290 | * |
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| 291 | * @var string $name name of the option |
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| 292 | * @var mixed $value value of the option |
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| 293 | * @access public |
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| 294 | */ |
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| 295 | public function setOption($name, $value) |
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| 321 | |||
| 322 | /** |
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| 323 | * Test if a cache is available and (if yes) return it |
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| 324 | * |
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| 325 | * @param string $id cache id |
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| 326 | * @param string $group name of the cache group |
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| 327 | * @param boolean $doNotTestCacheValidity if set to true, the cache validity won't be tested |
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| 328 | * @return string data of the cache (else : false) |
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| 329 | * @access public |
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| 330 | */ |
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| 331 | public function get($id, $group = 'default', $doNotTestCacheValidity = false) |
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| 373 | |||
| 374 | /** |
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| 375 | * Save some data in a cache file |
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| 376 | * |
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| 377 | * @param string $data data to put in cache (can be another type than strings if automaticSerialization is on) |
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| 378 | * @param string $id cache id |
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| 379 | * @param string $group name of the cache group |
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| 380 | * @return boolean true if no problem (else : false or a PEAR_Error object) |
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| 381 | * @access public |
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| 382 | */ |
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| 383 | public function save($data, $id = null, $group = 'default') |
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| 427 | |||
| 428 | /** |
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| 429 | * Remove a cache file |
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| 430 | * |
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| 431 | * @param string $id cache id |
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| 432 | * @param string $group name of the cache group |
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| 433 | * @param boolean $checkbeforeunlink check if file exists before removing it |
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| 434 | * @return boolean true if no problem |
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| 435 | * @access public |
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| 436 | */ |
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| 437 | public function remove($id, $group = 'default', $checkbeforeunlink = false) |
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| 457 | |||
| 458 | /** |
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| 459 | * Clean the cache |
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| 460 | * |
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| 461 | * if no group is specified all cache files will be destroyed |
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| 462 | * else only cache files of the specified group will be destroyed |
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| 463 | * |
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| 464 | * @param bool|string $group name of the cache group |
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| 465 | * @param string $mode flush cache mode : 'old', 'ingroup', 'notingroup', |
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| 466 | * 'callback_myFunction' |
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| 467 | * @return bool true if no problem |
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| 468 | * @access public |
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| 469 | */ |
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| 470 | public function clean($group = false, $mode = 'ingroup') |
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| 474 | |||
| 475 | /** |
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| 476 | * Set to debug mode |
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| 477 | * |
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| 478 | * When an error is found, the script will stop and the message will be displayed |
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| 479 | * (in debug mode only). |
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| 480 | * |
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| 481 | * @access public |
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| 482 | */ |
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| 483 | public function setToDebug() |
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| 487 | |||
| 488 | /** |
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| 489 | * Set a new life time |
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| 490 | * |
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| 491 | * @param int $newLifeTime new life time (in seconds) |
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| 492 | * @access public |
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| 493 | */ |
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| 494 | public function setLifeTime($newLifeTime) |
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| 499 | |||
| 500 | /** |
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| 501 | * Save the state of the caching memory array into a cache file cache |
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| 502 | * |
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| 503 | * @param string $id cache id |
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| 504 | * @param string $group name of the cache group |
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| 505 | * @access public |
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| 506 | */ |
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| 507 | public function saveMemoryCachingState($id, $group = 'default') |
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| 518 | |||
| 519 | /** |
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| 520 | * Load the state of the caching memory array from a given cache file cache |
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| 521 | * |
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| 522 | * @param string $id cache id |
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| 523 | * @param string $group name of the cache group |
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| 524 | * @param boolean $doNotTestCacheValidity if set to true, the cache validity won't be tested |
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| 525 | * @access public |
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| 526 | */ |
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| 527 | public function getMemoryCachingState($id, $group = 'default', $doNotTestCacheValidity = false) |
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| 537 | |||
| 538 | /** |
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| 539 | * Return the cache last modification time |
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| 540 | * |
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| 541 | * BE CAREFUL : THIS METHOD IS FOR HACKING ONLY ! |
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| 542 | * |
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| 543 | * @return int last modification time |
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| 544 | */ |
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| 545 | public function lastModified() |
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| 549 | |||
| 550 | /** |
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| 551 | * Trigger a PEAR error |
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| 552 | * |
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| 553 | * To improve performances, the PEAR.php file is included dynamically. |
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| 554 | * The file is so included only when an error is triggered. So, in most |
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| 555 | * cases, the file isn't included and perfs are much better. |
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| 556 | * |
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| 557 | * @param string $msg error message |
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| 558 | * @param int $code error code |
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| 559 | * @access public |
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| 560 | * @return object |
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| 561 | */ |
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| 562 | public function raiseError($msg, $code) |
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| 568 | |||
| 569 | /** |
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| 570 | * Extend the life of a valid cache file |
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| 571 | * |
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| 572 | * see http://pear.php.net/bugs/bug.php?id=6681 |
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| 573 | * |
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| 574 | * @access public |
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| 575 | */ |
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| 576 | public function extendLife() |
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| 580 | |||
| 581 | // --- Private methods --- |
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| 582 | |||
| 583 | /** |
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| 584 | * Compute & set the refresh time |
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| 585 | * |
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| 586 | * @access private |
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| 587 | */ |
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| 588 | public function _setRefreshTime() |
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| 596 | |||
| 597 | /** |
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| 598 | * Remove a file |
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| 599 | * |
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| 600 | * @param string $file complete file path and name |
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| 601 | * @return boolean true if no problem |
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| 602 | * @access private |
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| 603 | */ |
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| 604 | public function _unlink($file) |
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| 612 | |||
| 613 | /** |
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| 614 | * Recursive function for cleaning cache file in the given directory |
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| 615 | * |
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| 616 | * @param string $dir directory complete path (with a trailing slash) |
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| 617 | * @param bool|string $group name of the cache group |
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| 618 | * @param string $mode flush cache mode : 'old', 'ingroup', 'notingroup', |
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| 619 | * 'callback_myFunction' |
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| 620 | * @return bool true if no problem |
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| 621 | * @access private |
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| 622 | */ |
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| 623 | public function _cleanDir($dir, $group = false, $mode = 'ingroup') |
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| 687 | |||
| 688 | /** |
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| 689 | * Add some date in the memory caching array |
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| 690 | * |
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| 691 | * @param string $data data to cache |
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| 692 | * @access private |
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| 693 | */ |
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| 694 | public function _memoryCacheAdd($data) |
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| 704 | |||
| 705 | /** |
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| 706 | * Make a file name (with path) |
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| 707 | * |
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| 708 | * @param string $id cache id |
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| 709 | * @param string $group name of the group |
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| 710 | * @access private |
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| 711 | */ |
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| 712 | public function _setFileName($id, $group) |
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| 729 | |||
| 730 | /** |
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| 731 | * Read the cache file and return the content |
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| 732 | * |
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| 733 | * @return string content of the cache file (else : false or a PEAR_Error object) |
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| 734 | * @access private |
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| 735 | */ |
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| 736 | public function _read() |
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| 779 | |||
| 780 | /** |
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| 781 | * Write the given data in the cache file |
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| 782 | * |
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| 783 | * @param string $data data to put in cache |
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| 784 | * @return boolean true if ok (a PEAR_Error object else) |
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| 785 | * @access private |
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| 786 | */ |
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| 787 | public function _write($data) |
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| 821 | |||
| 822 | /** |
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| 823 | * Write the given data in the cache file and control it just after to avoir corrupted cache entries |
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| 824 | * |
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| 825 | * @param string $data data to put in cache |
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| 826 | * @return boolean true if the test is ok (else : false or a PEAR_Error object) |
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| 827 | * @access private |
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| 828 | */ |
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| 829 | public function _writeAndControl($data) |
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| 845 | |||
| 846 | /** |
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| 847 | * Make a control key with the string containing datas |
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| 848 | * |
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| 849 | * @param string $data data |
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| 850 | * @param string $controlType type of control 'md5', 'crc32' or 'strlen' |
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| 851 | * @return string control key |
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| 852 | * @access private |
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| 853 | */ |
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| 854 | public function _hash($data, $controlType) |
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| 867 | } |
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| 868 |
You can fix this by adding a namespace to your class:
When choosing a vendor namespace, try to pick something that is not too generic to avoid conflicts with other libraries.