wikimedia /
mediawiki
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 WatchedItemStore 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 WatchedItemStore, and based on these observations, apply Extract Interface, too.
| 1 | <?php |
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| 16 | class WatchedItemStore implements StatsdAwareInterface { |
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| 17 | |||
| 18 | const SORT_DESC = 'DESC'; |
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| 19 | const SORT_ASC = 'ASC'; |
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| 20 | |||
| 21 | /** |
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| 22 | * @var LoadBalancer |
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| 23 | */ |
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| 24 | private $loadBalancer; |
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| 25 | |||
| 26 | /** |
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| 27 | * @var HashBagOStuff |
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| 28 | */ |
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| 29 | private $cache; |
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| 30 | |||
| 31 | /** |
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| 32 | * @var array[] Looks like $cacheIndex[Namespace ID][Target DB Key][User Id] => 'key' |
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| 33 | * The index is needed so that on mass changes all relevant items can be un-cached. |
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| 34 | * For example: Clearing a users watchlist of all items or updating notification timestamps |
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| 35 | * for all users watching a single target. |
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| 36 | */ |
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| 37 | private $cacheIndex = []; |
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| 38 | |||
| 39 | /** |
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| 40 | * @var callable|null |
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| 41 | */ |
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| 42 | private $deferredUpdatesAddCallableUpdateCallback; |
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| 43 | |||
| 44 | /** |
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| 45 | * @var callable|null |
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| 46 | */ |
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| 47 | private $revisionGetTimestampFromIdCallback; |
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| 48 | |||
| 49 | /** |
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| 50 | * @var StatsdDataFactoryInterface |
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| 51 | */ |
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| 52 | private $stats; |
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| 53 | |||
| 54 | /** |
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| 55 | * @param LoadBalancer $loadBalancer |
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| 56 | * @param HashBagOStuff $cache |
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| 57 | */ |
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| 58 | public function __construct( |
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| 68 | |||
| 69 | public function setStatsdDataFactory( StatsdDataFactoryInterface $stats ) { |
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| 72 | |||
| 73 | /** |
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| 74 | * Overrides the DeferredUpdates::addCallableUpdate callback |
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| 75 | * This is intended for use while testing and will fail if MW_PHPUNIT_TEST is not defined. |
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| 76 | * |
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| 77 | * @param callable $callback |
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| 78 | * |
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| 79 | * @see DeferredUpdates::addCallableUpdate for callback signiture |
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| 80 | * |
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| 81 | * @return ScopedCallback to reset the overridden value |
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| 82 | * @throws MWException |
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| 83 | */ |
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| 84 | View Code Duplication | public function overrideDeferredUpdatesAddCallableUpdateCallback( callable $callback ) { |
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| 96 | |||
| 97 | /** |
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| 98 | * Overrides the Revision::getTimestampFromId callback |
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| 99 | * This is intended for use while testing and will fail if MW_PHPUNIT_TEST is not defined. |
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| 100 | * |
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| 101 | * @param callable $callback |
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| 102 | * @see Revision::getTimestampFromId for callback signiture |
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| 103 | * |
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| 104 | * @return ScopedCallback to reset the overridden value |
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| 105 | * @throws MWException |
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| 106 | */ |
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| 107 | View Code Duplication | public function overrideRevisionGetTimestampFromIdCallback( callable $callback ) { |
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| 119 | |||
| 120 | private function getCacheKey( User $user, LinkTarget $target ) { |
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| 127 | |||
| 128 | private function cache( WatchedItem $item ) { |
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| 136 | |||
| 137 | private function uncache( User $user, LinkTarget $target ) { |
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| 142 | |||
| 143 | private function uncacheLinkTarget( LinkTarget $target ) { |
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| 153 | |||
| 154 | private function uncacheUser( User $user ) { |
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| 165 | |||
| 166 | /** |
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| 167 | * @param User $user |
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| 168 | * @param LinkTarget $target |
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| 169 | * |
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| 170 | * @return WatchedItem|false |
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| 171 | */ |
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| 172 | private function getCached( User $user, LinkTarget $target ) { |
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| 175 | |||
| 176 | /** |
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| 177 | * Return an array of conditions to select or update the appropriate database |
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| 178 | * row. |
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| 179 | * |
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| 180 | * @param User $user |
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| 181 | * @param LinkTarget $target |
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| 182 | * |
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| 183 | * @return array |
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| 184 | */ |
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| 185 | private function dbCond( User $user, LinkTarget $target ) { |
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| 192 | |||
| 193 | /** |
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| 194 | * @param int $dbIndex DB_MASTER or DB_REPLICA |
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| 195 | * |
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| 196 | * @return IDatabase |
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| 197 | * @throws MWException |
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| 198 | */ |
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| 199 | private function getConnectionRef( $dbIndex ) { |
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| 202 | |||
| 203 | /** |
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| 204 | * Count the number of individual items that are watched by the user. |
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| 205 | * If a subject and corresponding talk page are watched this will return 2. |
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| 206 | * |
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| 207 | * @param User $user |
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| 208 | * |
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| 209 | * @return int |
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| 210 | */ |
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| 211 | public function countWatchedItems( User $user ) { |
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| 224 | |||
| 225 | /** |
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| 226 | * @param LinkTarget $target |
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| 227 | * |
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| 228 | * @return int |
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| 229 | */ |
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| 230 | public function countWatchers( LinkTarget $target ) { |
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| 244 | |||
| 245 | /** |
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| 246 | * Number of page watchers who also visited a "recent" edit |
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| 247 | * |
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| 248 | * @param LinkTarget $target |
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| 249 | * @param mixed $threshold timestamp accepted by wfTimestamp |
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| 250 | * |
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| 251 | * @return int |
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| 252 | * @throws DBUnexpectedError |
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| 253 | * @throws MWException |
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| 254 | */ |
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| 255 | public function countVisitingWatchers( LinkTarget $target, $threshold ) { |
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| 272 | |||
| 273 | /** |
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| 274 | * @param LinkTarget[] $targets |
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| 275 | * @param array $options Allowed keys: |
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| 276 | * 'minimumWatchers' => int |
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| 277 | * |
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| 278 | * @return array multi dimensional like $return[$namespaceId][$titleString] = int $watchers |
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| 279 | * All targets will be present in the result. 0 either means no watchers or the number |
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| 280 | * of watchers was below the minimumWatchers option if passed. |
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| 281 | */ |
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| 282 | public function countWatchersMultiple( array $targets, array $options = [] ) { |
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| 311 | |||
| 312 | /** |
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| 313 | * Number of watchers of each page who have visited recent edits to that page |
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| 314 | * |
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| 315 | * @param array $targetsWithVisitThresholds array of pairs (LinkTarget $target, mixed $threshold), |
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| 316 | * $threshold is: |
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| 317 | * - a timestamp of the recent edit if $target exists (format accepted by wfTimestamp) |
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| 318 | * - null if $target doesn't exist |
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| 319 | * @param int|null $minimumWatchers |
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| 320 | * @return array multi-dimensional like $return[$namespaceId][$titleString] = $watchers, |
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| 321 | * where $watchers is an int: |
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| 322 | * - if the page exists, number of users watching who have visited the page recently |
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| 323 | * - if the page doesn't exist, number of users that have the page on their watchlist |
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| 324 | * - 0 means there are no visiting watchers or their number is below the minimumWatchers |
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| 325 | * option (if passed). |
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| 326 | */ |
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| 327 | public function countVisitingWatchersMultiple( |
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| 359 | |||
| 360 | /** |
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| 361 | * Generates condition for the query used in a batch count visiting watchers. |
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| 362 | * |
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| 363 | * @param IDatabase $db |
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| 364 | * @param array $targetsWithVisitThresholds array of pairs (LinkTarget, last visit threshold) |
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| 365 | * @return string |
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| 366 | */ |
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| 367 | private function getVisitingWatchersCondition( |
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| 403 | |||
| 404 | /** |
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| 405 | * Get an item (may be cached) |
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| 406 | * |
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| 407 | * @param User $user |
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| 408 | * @param LinkTarget $target |
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| 409 | * |
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| 410 | * @return WatchedItem|false |
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| 411 | */ |
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| 412 | public function getWatchedItem( User $user, LinkTarget $target ) { |
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| 425 | |||
| 426 | /** |
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| 427 | * Loads an item from the db |
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| 428 | * |
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| 429 | * @param User $user |
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| 430 | * @param LinkTarget $target |
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| 431 | * |
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| 432 | * @return WatchedItem|false |
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| 433 | */ |
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| 434 | public function loadWatchedItem( User $user, LinkTarget $target ) { |
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| 461 | |||
| 462 | /** |
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| 463 | * @param User $user |
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| 464 | * @param array $options Allowed keys: |
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| 465 | * 'forWrite' => bool defaults to false |
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| 466 | * 'sort' => string optional sorting by namespace ID and title |
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| 467 | * one of the self::SORT_* constants |
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| 468 | * |
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| 469 | * @return WatchedItem[] |
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| 470 | */ |
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| 471 | public function getWatchedItemsForUser( User $user, array $options = [] ) { |
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| 508 | |||
| 509 | /** |
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| 510 | * Must be called separately for Subject & Talk namespaces |
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| 511 | * |
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| 512 | * @param User $user |
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| 513 | * @param LinkTarget $target |
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| 514 | * |
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| 515 | * @return bool |
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| 516 | */ |
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| 517 | public function isWatched( User $user, LinkTarget $target ) { |
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| 520 | |||
| 521 | /** |
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| 522 | * @param User $user |
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| 523 | * @param LinkTarget[] $targets |
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| 524 | * |
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| 525 | * @return array multi-dimensional like $return[$namespaceId][$titleString] = $timestamp, |
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| 526 | * where $timestamp is: |
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| 527 | * - string|null value of wl_notificationtimestamp, |
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| 528 | * - false if $target is not watched by $user. |
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| 529 | */ |
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| 530 | public function getNotificationTimestampsBatch( User $user, array $targets ) { |
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| 574 | |||
| 575 | /** |
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| 576 | * Must be called separately for Subject & Talk namespaces |
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| 577 | * |
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| 578 | * @param User $user |
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| 579 | * @param LinkTarget $target |
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| 580 | */ |
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| 581 | public function addWatch( User $user, LinkTarget $target ) { |
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| 584 | |||
| 585 | /** |
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| 586 | * @param User $user |
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| 587 | * @param LinkTarget[] $targets |
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| 588 | * |
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| 589 | * @return bool success |
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| 590 | */ |
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| 591 | public function addWatchBatchForUser( User $user, array $targets ) { |
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| 636 | |||
| 637 | /** |
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| 638 | * Removes the an entry for the User watching the LinkTarget |
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| 639 | * Must be called separately for Subject & Talk namespaces |
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| 640 | * |
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| 641 | * @param User $user |
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| 642 | * @param LinkTarget $target |
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| 643 | * |
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| 644 | * @return bool success |
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| 645 | * @throws DBUnexpectedError |
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| 646 | * @throws MWException |
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| 647 | */ |
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| 648 | public function removeWatch( User $user, LinkTarget $target ) { |
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| 668 | |||
| 669 | /** |
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| 670 | * @param User $user The user to set the timestamp for |
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| 671 | * @param string $timestamp Set the update timestamp to this value |
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| 672 | * @param LinkTarget[] $targets List of targets to update. Default to all targets |
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| 673 | * |
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| 674 | * @return bool success |
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| 675 | */ |
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| 676 | public function setNotificationTimestampsForUser( User $user, $timestamp, array $targets = [] ) { |
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| 701 | |||
| 702 | /** |
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| 703 | * @param User $editor The editor that triggered the update. Their notification |
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| 704 | * timestamp will not be updated(they have already seen it) |
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| 705 | * @param LinkTarget $target The target to update timestamps for |
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| 706 | * @param string $timestamp Set the update timestamp to this value |
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| 707 | * |
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| 708 | * @return int[] Array of user IDs the timestamp has been updated for |
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| 709 | */ |
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| 710 | public function updateNotificationTimestamp( User $editor, LinkTarget $target, $timestamp ) { |
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| 762 | |||
| 763 | /** |
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| 764 | * Reset the notification timestamp of this entry |
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| 765 | * |
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| 766 | * @param User $user |
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| 767 | * @param Title $title |
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| 768 | * @param string $force Whether to force the write query to be executed even if the |
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| 769 | * page is not watched or the notification timestamp is already NULL. |
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| 770 | * 'force' in order to force |
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| 771 | * @param int $oldid The revision id being viewed. If not given or 0, latest revision is assumed. |
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| 772 | * |
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| 773 | * @return bool success |
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| 774 | */ |
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| 775 | public function resetNotificationTimestamp( User $user, Title $title, $force = '', $oldid = 0 ) { |
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| 813 | |||
| 814 | private function getNotificationTimestamp( User $user, Title $title, $item, $force, $oldid ) { |
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| 860 | |||
| 861 | /** |
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| 862 | * @param User $user |
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| 863 | * @param int $unreadLimit |
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| 864 | * |
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| 865 | * @return int|bool The number of unread notifications |
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| 866 | * true if greater than or equal to $unreadLimit |
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| 867 | */ |
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| 868 | public function countUnreadNotifications( User $user, $unreadLimit = null ) { |
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| 897 | |||
| 898 | /** |
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| 899 | * Check if the given title already is watched by the user, and if so |
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| 900 | * add a watch for the new title. |
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| 901 | * |
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| 902 | * To be used for page renames and such. |
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| 903 | * |
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| 904 | * @param LinkTarget $oldTarget |
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| 905 | * @param LinkTarget $newTarget |
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| 906 | */ |
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| 907 | public function duplicateAllAssociatedEntries( LinkTarget $oldTarget, LinkTarget $newTarget ) { |
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| 914 | |||
| 915 | /** |
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| 916 | * Check if the given title already is watched by the user, and if so |
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| 917 | * add a watch for the new title. |
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| 918 | * |
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| 919 | * To be used for page renames and such. |
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| 920 | * This must be called separately for Subject and Talk pages |
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| 921 | * |
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| 922 | * @param LinkTarget $oldTarget |
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| 923 | * @param LinkTarget $newTarget |
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| 924 | */ |
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| 925 | public function duplicateEntry( LinkTarget $oldTarget, LinkTarget $newTarget ) { |
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| 965 | |||
| 966 | } |
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| 967 |
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Let’s assume that you have a directory layout like this:
. |-- OtherDir | |-- Bar.php | `-- Foo.php `-- SomeDir `-- Foo.phpand let’s assume the following content of
Bar.php:If both files
OtherDir/Foo.phpandSomeDir/Foo.phpare loaded in the same runtime, you will see a PHP error such as the following:PHP Fatal error: Cannot use SomeDir\Foo as Foo because the name is already in use in OtherDir/Foo.phpHowever, as
OtherDir/Foo.phpdoes not necessarily have to be loaded and the error is only triggered if it is loaded beforeOtherDir/Bar.php, this problem might go unnoticed for a while. In order to prevent this error from surfacing, you must import the namespace with a different alias: