includes/changetags/ChangeTags.php

   1 <?php
   2 /**
   3  * Recent changes tagging.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  * @ingroup Change tagging
  22  */
  23
  24 class ChangeTags {
  25         /**
  26          * Can't delete tags with more than this many uses. Similar in intent to
  27          * the bigdelete user right
  28          * @todo Use the job queue for tag deletion to avoid this restriction
  29          */
  30         const MAX_DELETE_USES = 5000;
  31
  32         /**
  33          * @var string[]
  34          */
  35         private static $coreTags = [ 'mw-contentmodelchange' ];
  36
  37         /**
  38          * Creates HTML for the given tags
  39          *
  40          * @param string $tags Comma-separated list of tags
  41          * @param string $page A label for the type of action which is being displayed,
  42          *   for example: 'history', 'contributions' or 'newpages'
  43          * @param IContextSource|null $context
  44          * @note Even though it takes null as a valid argument, an IContextSource is preferred
  45          *       in a new code, as the null value is subject to change in the future
  46          * @return array Array with two items: (html, classes)
  47          *   - html: String: HTML for displaying the tags (empty string when param $tags is empty)
  48          *   - classes: Array of strings: CSS classes used in the generated html, one class for each tag
  49          */
  50         public static function formatSummaryRow( $tags, $page, IContextSource $context = null ) {
  51                 if ( !$tags ) {
  52                         return [ '', [] ];
  53                 }
  54                 if ( !$context ) {
  55                         $context = RequestContext::getMain();
  56                 }
  57
  58                 $classes = [];
  59
  60                 $tags = explode( ',', $tags );
  61                 $displayTags = [];
  62                 foreach ( $tags as $tag ) {
  63                         if ( !$tag ) {
  64                                 continue;
  65                         }
  66                         $description = self::tagDescription( $tag );
  67                         if ( $description === false ) {
  68                                 continue;
  69                         }
  70                         $displayTags[] = Xml::tags(
  71                                 'span',
  72                                 [ 'class' => 'mw-tag-marker ' .
  73                                                                 Sanitizer::escapeClass( "mw-tag-marker-$tag" ) ],
  74                                 $description
  75                         );
  76                         $classes[] = Sanitizer::escapeClass( "mw-tag-$tag" );
  77                 }
  78
  79                 if ( !$displayTags ) {
  80                         return [ '', [] ];
  81                 }
  82
  83                 $markers = $context->msg( 'tag-list-wrapper' )
  84                         ->numParams( count( $displayTags ) )
  85                         ->rawParams( $context->getLanguage()->commaList( $displayTags ) )
  86                         ->parse();
  87                 $markers = Xml::tags( 'span', [ 'class' => 'mw-tag-markers' ], $markers );
  88
  89                 return [ $markers, $classes ];
  90         }
  91
  92         /**
  93          * Get a short description for a tag.
  94          *
  95          * Checks if message key "mediawiki:tag-$tag" exists. If it does not,
  96          * returns the HTML-escaped tag name. Uses the message if the message
  97          * exists, provided it is not disabled. If the message is disabled,
  98          * we consider the tag hidden, and return false.
  99          *
 100          * @param string $tag Tag
 101          * @return string|bool Tag description or false if tag is to be hidden.
 102          * @since 1.25 Returns false if tag is to be hidden.
 103          */
 104         public static function tagDescription( $tag ) {
 105                 $msg = wfMessage( "tag-$tag" );
 106                 if ( !$msg->exists() ) {
 107                         // No such message, so return the HTML-escaped tag name.
 108                         return htmlspecialchars( $tag );
 109                 }
 110                 if ( $msg->isDisabled() ) {
 111                         // The message exists but is disabled, hide the tag.
 112                         return false;
 113                 }
 114
 115                 // Message exists and isn't disabled, use it.
 116                 return $msg->parse();
 117         }
 118
 119         /**
 120          * Add tags to a change given its rc_id, rev_id and/or log_id
 121          *
 122          * @param string|string[] $tags Tags to add to the change
 123          * @param int|null $rc_id The rc_id of the change to add the tags to
 124          * @param int|null $rev_id The rev_id of the change to add the tags to
 125          * @param int|null $log_id The log_id of the change to add the tags to
 126          * @param string $params Params to put in the ct_params field of table 'change_tag'
 127          * @param RecentChange|null $rc Recent change, in case the tagging accompanies the action
 128          * (this should normally be the case)
 129          *
 130          * @throws MWException
 131          * @return bool False if no changes are made, otherwise true
 132          */
 133         public static function addTags( $tags, $rc_id = null, $rev_id = null,
 134                 $log_id = null, $params = null, RecentChange $rc = null
 135         ) {
 136                 $result = self::updateTags( $tags, null, $rc_id, $rev_id, $log_id, $params, $rc );
 137                 return (bool)$result[0];
 138         }
 139
 140         /**
 141          * Add and remove tags to/from a change given its rc_id, rev_id and/or log_id,
 142          * without verifying that the tags exist or are valid. If a tag is present in
 143          * both $tagsToAdd and $tagsToRemove, it will be removed.
 144          *
 145          * This function should only be used by extensions to manipulate tags they
 146          * have registered using the ListDefinedTags hook. When dealing with user
 147          * input, call updateTagsWithChecks() instead.
 148          *
 149          * @param string|array|null $tagsToAdd Tags to add to the change
 150          * @param string|array|null $tagsToRemove Tags to remove from the change
 151          * @param int|null &$rc_id The rc_id of the change to add the tags to.
 152          * Pass a variable whose value is null if the rc_id is not relevant or unknown.
 153          * @param int|null &$rev_id The rev_id of the change to add the tags to.
 154          * Pass a variable whose value is null if the rev_id is not relevant or unknown.
 155          * @param int|null &$log_id The log_id of the change to add the tags to.
 156          * Pass a variable whose value is null if the log_id is not relevant or unknown.
 157          * @param string $params Params to put in the ct_params field of table
 158          * 'change_tag' when adding tags
 159          * @param RecentChange|null $rc Recent change being tagged, in case the tagging accompanies
 160          * the action
 161          * @param User|null $user Tagging user, in case the tagging is subsequent to the tagged action
 162          *
 163          * @throws MWException When $rc_id, $rev_id and $log_id are all null
 164          * @return array Index 0 is an array of tags actually added, index 1 is an
 165          * array of tags actually removed, index 2 is an array of tags present on the
 166          * revision or log entry before any changes were made
 167          *
 168          * @since 1.25
 169          */
 170         public static function updateTags( $tagsToAdd, $tagsToRemove, &$rc_id = null,
 171                 &$rev_id = null, &$log_id = null, $params = null, RecentChange $rc = null,
 172                 User $user = null
 173         ) {
 174
 175                 $tagsToAdd = array_filter( (array)$tagsToAdd ); // Make sure we're submitting all tags...
 176                 $tagsToRemove = array_filter( (array)$tagsToRemove );
 177
 178                 if ( !$rc_id && !$rev_id && !$log_id ) {
 179                         throw new MWException( 'At least one of: RCID, revision ID, and log ID MUST be ' .
 180                                 'specified when adding or removing a tag from a change!' );
 181                 }
 182
 183                 $dbw = wfGetDB( DB_MASTER );
 184
 185                 // Might as well look for rcids and so on.
 186                 if ( !$rc_id ) {
 187                         // Info might be out of date, somewhat fractionally, on replica DB.
 188                         // LogEntry/LogPage and WikiPage match rev/log/rc timestamps,
 189                         // so use that relation to avoid full table scans.
 190                         if ( $log_id ) {
 191                                 $rc_id = $dbw->selectField(
 192                                         [ 'logging', 'recentchanges' ],
 193                                         'rc_id',
 194                                         [
 195                                                 'log_id' => $log_id,
 196                                                 'rc_timestamp = log_timestamp',
 197                                                 'rc_logid = log_id'
 198                                         ],
 199                                         __METHOD__
 200                                 );
 201                         } elseif ( $rev_id ) {
 202                                 $rc_id = $dbw->selectField(
 203                                         [ 'revision', 'recentchanges' ],
 204                                         'rc_id',
 205                                         [
 206                                                 'rev_id' => $rev_id,
 207                                                 'rc_timestamp = rev_timestamp',
 208                                                 'rc_this_oldid = rev_id'
 209                                         ],
 210                                         __METHOD__
 211                                 );
 212                         }
 213                 } elseif ( !$log_id && !$rev_id ) {
 214                         // Info might be out of date, somewhat fractionally, on replica DB.
 215                         $log_id = $dbw->selectField(
 216                                 'recentchanges',
 217                                 'rc_logid',
 218                                 [ 'rc_id' => $rc_id ],
 219                                 __METHOD__
 220                         );
 221                         $rev_id = $dbw->selectField(
 222                                 'recentchanges',
 223                                 'rc_this_oldid',
 224                                 [ 'rc_id' => $rc_id ],
 225                                 __METHOD__
 226                         );
 227                 }
 228
 229                 if ( $log_id && !$rev_id ) {
 230                         $rev_id = $dbw->selectField(
 231                                 'log_search',
 232                                 'ls_value',
 233                                 [ 'ls_field' => 'associated_rev_id', 'ls_log_id' => $log_id ],
 234                                 __METHOD__
 235                         );
 236                 } elseif ( !$log_id && $rev_id ) {
 237                         $log_id = $dbw->selectField(
 238                                 'log_search',
 239                                 'ls_log_id',
 240                                 [ 'ls_field' => 'associated_rev_id', 'ls_value' => $rev_id ],
 241                                 __METHOD__
 242                         );
 243                 }
 244
 245                 // update the tag_summary row
 246                 $prevTags = [];
 247                 if ( !self::updateTagSummaryRow( $tagsToAdd, $tagsToRemove, $rc_id, $rev_id,
 248                         $log_id, $prevTags ) ) {
 249
 250                         // nothing to do
 251                         return [ [], [], $prevTags ];
 252                 }
 253
 254                 // insert a row into change_tag for each new tag
 255                 if ( count( $tagsToAdd ) ) {
 256                         $tagsRows = [];
 257                         foreach ( $tagsToAdd as $tag ) {
 258                                 // Filter so we don't insert NULLs as zero accidentally.
 259                                 // Keep in mind that $rc_id === null means "I don't care/know about the
 260                                 // rc_id, just delete $tag on this revision/log entry". It doesn't
 261                                 // mean "only delete tags on this revision/log WHERE rc_id IS NULL".
 262                                 $tagsRows[] = array_filter(
 263                                         [
 264                                                 'ct_tag' => $tag,
 265                                                 'ct_rc_id' => $rc_id,
 266                                                 'ct_log_id' => $log_id,
 267                                                 'ct_rev_id' => $rev_id,
 268                                                 'ct_params' => $params
 269                                         ]
 270                                 );
 271                         }
 272
 273                         $dbw->insert( 'change_tag', $tagsRows, __METHOD__, [ 'IGNORE' ] );
 274                 }
 275
 276                 // delete from change_tag
 277                 if ( count( $tagsToRemove ) ) {
 278                         foreach ( $tagsToRemove as $tag ) {
 279                                 $conds = array_filter(
 280                                         [
 281                                                 'ct_tag' => $tag,
 282                                                 'ct_rc_id' => $rc_id,
 283                                                 'ct_log_id' => $log_id,
 284                                                 'ct_rev_id' => $rev_id
 285                                         ]
 286                                 );
 287                                 $dbw->delete( 'change_tag', $conds, __METHOD__ );
 288                         }
 289                 }
 290
 291                 self::purgeTagUsageCache();
 292
 293                 Hooks::run( 'ChangeTagsAfterUpdateTags', [ $tagsToAdd, $tagsToRemove, $prevTags,
 294                         $rc_id, $rev_id, $log_id, $params, $rc, $user ] );
 295
 296                 return [ $tagsToAdd, $tagsToRemove, $prevTags ];
 297         }
 298
 299         /**
 300          * Adds or removes a given set of tags to/from the relevant row of the
 301          * tag_summary table. Modifies the tagsToAdd and tagsToRemove arrays to
 302          * reflect the tags that were actually added and/or removed.
 303          *
 304          * @param array &$tagsToAdd
 305          * @param array &$tagsToRemove If a tag is present in both $tagsToAdd and
 306          * $tagsToRemove, it will be removed
 307          * @param int|null $rc_id Null if not known or not applicable
 308          * @param int|null $rev_id Null if not known or not applicable
 309          * @param int|null $log_id Null if not known or not applicable
 310          * @param array &$prevTags Optionally outputs a list of the tags that were
 311          * in the tag_summary row to begin with
 312          * @return bool True if any modifications were made, otherwise false
 313          * @since 1.25
 314          */
 315         protected static function updateTagSummaryRow( &$tagsToAdd, &$tagsToRemove,
 316                 $rc_id, $rev_id, $log_id, &$prevTags = [] ) {
 317
 318                 $dbw = wfGetDB( DB_MASTER );
 319
 320                 $tsConds = array_filter( [
 321                         'ts_rc_id' => $rc_id,
 322                         'ts_rev_id' => $rev_id,
 323                         'ts_log_id' => $log_id
 324                 ] );
 325
 326                 // Can't both add and remove a tag at the same time...
 327                 $tagsToAdd = array_diff( $tagsToAdd, $tagsToRemove );
 328
 329                 // Update the summary row.
 330                 // $prevTags can be out of date on replica DBs, especially when addTags is called consecutively,
 331                 // causing loss of tags added recently in tag_summary table.
 332                 $prevTags = $dbw->selectField( 'tag_summary', 'ts_tags', $tsConds, __METHOD__ );
 333                 $prevTags = $prevTags ? $prevTags : '';
 334                 $prevTags = array_filter( explode( ',', $prevTags ) );
 335
 336                 // add tags
 337                 $tagsToAdd = array_values( array_diff( $tagsToAdd, $prevTags ) );
 338                 $newTags = array_unique( array_merge( $prevTags, $tagsToAdd ) );
 339
 340                 // remove tags
 341                 $tagsToRemove = array_values( array_intersect( $tagsToRemove, $newTags ) );
 342                 $newTags = array_values( array_diff( $newTags, $tagsToRemove ) );
 343
 344                 sort( $prevTags );
 345                 sort( $newTags );
 346                 if ( $prevTags == $newTags ) {
 347                         // No change.
 348                         return false;
 349                 }
 350
 351                 if ( !$newTags ) {
 352                         // no tags left, so delete the row altogether
 353                         $dbw->delete( 'tag_summary', $tsConds, __METHOD__ );
 354                 } else {
 355                         $dbw->replace( 'tag_summary',
 356                                 [ 'ts_rev_id', 'ts_rc_id', 'ts_log_id' ],
 357                                 array_filter( array_merge( $tsConds, [ 'ts_tags' => implode( ',', $newTags ) ] ) ),
 358                                 __METHOD__
 359                         );
 360                 }
 361
 362                 return true;
 363         }
 364
 365         /**
 366          * Helper function to generate a fatal status with a 'not-allowed' type error.
 367          *
 368          * @param string $msgOne Message key to use in the case of one tag
 369          * @param string $msgMulti Message key to use in the case of more than one tag
 370          * @param array $tags Restricted tags (passed as $1 into the message, count of
 371          * $tags passed as $2)
 372          * @return Status
 373          * @since 1.25
 374          */
 375         protected static function restrictedTagError( $msgOne, $msgMulti, $tags ) {
 376                 $lang = RequestContext::getMain()->getLanguage();
 377                 $count = count( $tags );
 378                 return Status::newFatal( ( $count > 1 ) ? $msgMulti : $msgOne,
 379                         $lang->commaList( $tags ), $count );
 380         }
 381
 382         /**
 383          * Is it OK to allow the user to apply all the specified tags at the same time
 384          * as they edit/make the change?
 385          *
 386          * @param array $tags Tags that you are interested in applying
 387          * @param User|null $user User whose permission you wish to check, or null if
 388          * you don't care (e.g. maintenance scripts)
 389          * @return Status
 390          * @since 1.25
 391          */
 392         public static function canAddTagsAccompanyingChange( array $tags,
 393                 User $user = null ) {
 394
 395                 if ( !is_null( $user ) ) {
 396                         if ( !$user->isAllowed( 'applychangetags' ) ) {
 397                                 return Status::newFatal( 'tags-apply-no-permission' );
 398                         } elseif ( $user->isBlocked() ) {
 399                                 return Status::newFatal( 'tags-apply-blocked' );
 400                         }
 401                 }
 402
 403                 // to be applied, a tag has to be explicitly defined
 404                 // @todo Allow extensions to define tags that can be applied by users...
 405                 $allowedTags = self::listExplicitlyDefinedTags();
 406                 $disallowedTags = array_diff( $tags, $allowedTags );
 407                 if ( $disallowedTags ) {
 408                         return self::restrictedTagError( 'tags-apply-not-allowed-one',
 409                                 'tags-apply-not-allowed-multi', $disallowedTags );
 410                 }
 411
 412                 return Status::newGood();
 413         }
 414
 415         /**
 416          * Adds tags to a given change, checking whether it is allowed first, but
 417          * without adding a log entry. Useful for cases where the tag is being added
 418          * along with the action that generated the change (e.g. tagging an edit as
 419          * it is being made).
 420          *
 421          * Extensions should not use this function, unless directly handling a user
 422          * request to add a particular tag. Normally, extensions should call
 423          * ChangeTags::updateTags() instead.
 424          *
 425          * @param array $tags Tags to apply
 426          * @param int|null $rc_id The rc_id of the change to add the tags to
 427          * @param int|null $rev_id The rev_id of the change to add the tags to
 428          * @param int|null $log_id The log_id of the change to add the tags to
 429          * @param string $params Params to put in the ct_params field of table
 430          * 'change_tag' when adding tags
 431          * @param User $user Who to give credit for the action
 432          * @return Status
 433          * @since 1.25
 434          */
 435         public static function addTagsAccompanyingChangeWithChecks(
 436                 array $tags, $rc_id, $rev_id, $log_id, $params, User $user
 437         ) {
 438
 439                 // are we allowed to do this?
 440                 $result = self::canAddTagsAccompanyingChange( $tags, $user );
 441                 if ( !$result->isOK() ) {
 442                         $result->value = null;
 443                         return $result;
 444                 }
 445
 446                 // do it!
 447                 self::addTags( $tags, $rc_id, $rev_id, $log_id, $params );
 448
 449                 return Status::newGood( true );
 450         }
 451
 452         /**
 453          * Is it OK to allow the user to adds and remove the given tags tags to/from a
 454          * change?
 455          *
 456          * @param array $tagsToAdd Tags that you are interested in adding
 457          * @param array $tagsToRemove Tags that you are interested in removing
 458          * @param User|null $user User whose permission you wish to check, or null if
 459          * you don't care (e.g. maintenance scripts)
 460          * @return Status
 461          * @since 1.25
 462          */
 463         public static function canUpdateTags( array $tagsToAdd, array $tagsToRemove,
 464                 User $user = null ) {
 465
 466                 if ( !is_null( $user ) ) {
 467                         if ( !$user->isAllowed( 'changetags' ) ) {
 468                                 return Status::newFatal( 'tags-update-no-permission' );
 469                         } elseif ( $user->isBlocked() ) {
 470                                 return Status::newFatal( 'tags-update-blocked' );
 471                         }
 472                 }
 473
 474                 if ( $tagsToAdd ) {
 475                         // to be added, a tag has to be explicitly defined
 476                         // @todo Allow extensions to define tags that can be applied by users...
 477                         $explicitlyDefinedTags = self::listExplicitlyDefinedTags();
 478                         $diff = array_diff( $tagsToAdd, $explicitlyDefinedTags );
 479                         if ( $diff ) {
 480                                 return self::restrictedTagError( 'tags-update-add-not-allowed-one',
 481                                         'tags-update-add-not-allowed-multi', $diff );
 482                         }
 483                 }
 484
 485                 if ( $tagsToRemove ) {
 486                         // to be removed, a tag must not be defined by an extension, or equivalently it
 487                         // has to be either explicitly defined or not defined at all
 488                         // (assuming no edge case of a tag both explicitly-defined and extension-defined)
 489                         $softwareDefinedTags = self::listSoftwareDefinedTags();
 490                         $intersect = array_intersect( $tagsToRemove, $softwareDefinedTags );
 491                         if ( $intersect ) {
 492                                 return self::restrictedTagError( 'tags-update-remove-not-allowed-one',
 493                                         'tags-update-remove-not-allowed-multi', $intersect );
 494                         }
 495                 }
 496
 497                 return Status::newGood();
 498         }
 499
 500         /**
 501          * Adds and/or removes tags to/from a given change, checking whether it is
 502          * allowed first, and adding a log entry afterwards.
 503          *
 504          * Includes a call to ChangeTag::canUpdateTags(), so your code doesn't need
 505          * to do that. However, it doesn't check whether the *_id parameters are a
 506          * valid combination. That is up to you to enforce. See ApiTag::execute() for
 507          * an example.
 508          *
 509          * @param array|null $tagsToAdd If none, pass array() or null
 510          * @param array|null $tagsToRemove If none, pass array() or null
 511          * @param int|null $rc_id The rc_id of the change to add the tags to
 512          * @param int|null $rev_id The rev_id of the change to add the tags to
 513          * @param int|null $log_id The log_id of the change to add the tags to
 514          * @param string $params Params to put in the ct_params field of table
 515          * 'change_tag' when adding tags
 516          * @param string $reason Comment for the log
 517          * @param User $user Who to give credit for the action
 518          * @return Status If successful, the value of this Status object will be an
 519          * object (stdClass) with the following fields:
 520          *  - logId: the ID of the added log entry, or null if no log entry was added
 521          *    (i.e. no operation was performed)
 522          *  - addedTags: an array containing the tags that were actually added
 523          *  - removedTags: an array containing the tags that were actually removed
 524          * @since 1.25
 525          */
 526         public static function updateTagsWithChecks( $tagsToAdd, $tagsToRemove,
 527                 $rc_id, $rev_id, $log_id, $params, $reason, User $user ) {
 528
 529                 if ( is_null( $tagsToAdd ) ) {
 530                         $tagsToAdd = [];
 531                 }
 532                 if ( is_null( $tagsToRemove ) ) {
 533                         $tagsToRemove = [];
 534                 }
 535                 if ( !$tagsToAdd && !$tagsToRemove ) {
 536                         // no-op, don't bother
 537                         return Status::newGood( (object)[
 538                                 'logId' => null,
 539                                 'addedTags' => [],
 540                                 'removedTags' => [],
 541                         ] );
 542                 }
 543
 544                 // are we allowed to do this?
 545                 $result = self::canUpdateTags( $tagsToAdd, $tagsToRemove, $user );
 546                 if ( !$result->isOK() ) {
 547                         $result->value = null;
 548                         return $result;
 549                 }
 550
 551                 // basic rate limiting
 552                 if ( $user->pingLimiter( 'changetag' ) ) {
 553                         return Status::newFatal( 'actionthrottledtext' );
 554                 }
 555
 556                 // do it!
 557                 list( $tagsAdded, $tagsRemoved, $initialTags ) = self::updateTags( $tagsToAdd,
 558                         $tagsToRemove, $rc_id, $rev_id, $log_id, $params, null, $user );
 559                 if ( !$tagsAdded && !$tagsRemoved ) {
 560                         // no-op, don't log it
 561                         return Status::newGood( (object)[
 562                                 'logId' => null,
 563                                 'addedTags' => [],
 564                                 'removedTags' => [],
 565                         ] );
 566                 }
 567
 568                 // log it
 569                 $logEntry = new ManualLogEntry( 'tag', 'update' );
 570                 $logEntry->setPerformer( $user );
 571                 $logEntry->setComment( $reason );
 572
 573                 // find the appropriate target page
 574                 if ( $rev_id ) {
 575                         $rev = Revision::newFromId( $rev_id );
 576                         if ( $rev ) {
 577                                 $logEntry->setTarget( $rev->getTitle() );
 578                         }
 579                 } elseif ( $log_id ) {
 580                         // This function is from revision deletion logic and has nothing to do with
 581                         // change tags, but it appears to be the only other place in core where we
 582                         // perform logged actions on log items.
 583                         $logEntry->setTarget( RevDelLogList::suggestTarget( null, [ $log_id ] ) );
 584                 }
 585
 586                 if ( !$logEntry->getTarget() ) {
 587                         // target is required, so we have to set something
 588                         $logEntry->setTarget( SpecialPage::getTitleFor( 'Tags' ) );
 589                 }
 590
 591                 $logParams = [
 592                         '4::revid' => $rev_id,
 593                         '5::logid' => $log_id,
 594                         '6:list:tagsAdded' => $tagsAdded,
 595                         '7:number:tagsAddedCount' => count( $tagsAdded ),
 596                         '8:list:tagsRemoved' => $tagsRemoved,
 597                         '9:number:tagsRemovedCount' => count( $tagsRemoved ),
 598                         'initialTags' => $initialTags,
 599                 ];
 600                 $logEntry->setParameters( $logParams );
 601                 $logEntry->setRelations( [ 'Tag' => array_merge( $tagsAdded, $tagsRemoved ) ] );
 602
 603                 $dbw = wfGetDB( DB_MASTER );
 604                 $logId = $logEntry->insert( $dbw );
 605                 // Only send this to UDP, not RC, similar to patrol events
 606                 $logEntry->publish( $logId, 'udp' );
 607
 608                 return Status::newGood( (object)[
 609                         'logId' => $logId,
 610                         'addedTags' => $tagsAdded,
 611                         'removedTags' => $tagsRemoved,
 612                 ] );
 613         }
 614
 615         /**
 616          * Applies all tags-related changes to a query.
 617          * Handles selecting tags, and filtering.
 618          * Needs $tables to be set up properly, so we can figure out which join conditions to use.
 619          *
 620          * @param string|array $tables Table names, see Database::select
 621          * @param string|array $fields Fields used in query, see Database::select
 622          * @param string|array $conds Conditions used in query, see Database::select
 623          * @param array $join_conds Join conditions, see Database::select
 624          * @param array $options Options, see Database::select
 625          * @param bool|string $filter_tag Tag to select on
 626          *
 627          * @throws MWException When unable to determine appropriate JOIN condition for tagging
 628          */
 629         public static function modifyDisplayQuery( &$tables, &$fields, &$conds,
 630                                                                                 &$join_conds, &$options, $filter_tag = false ) {
 631                 global $wgRequest, $wgUseTagFilter;
 632
 633                 if ( $filter_tag === false ) {
 634                         $filter_tag = $wgRequest->getVal( 'tagfilter' );
 635                 }
 636
 637                 // Figure out which conditions can be done.
 638                 if ( in_array( 'recentchanges', $tables ) ) {
 639                         $join_cond = 'ct_rc_id=rc_id';
 640                 } elseif ( in_array( 'logging', $tables ) ) {
 641                         $join_cond = 'ct_log_id=log_id';
 642                 } elseif ( in_array( 'revision', $tables ) ) {
 643                         $join_cond = 'ct_rev_id=rev_id';
 644                 } elseif ( in_array( 'archive', $tables ) ) {
 645                         $join_cond = 'ct_rev_id=ar_rev_id';
 646                 } else {
 647                         throw new MWException( 'Unable to determine appropriate JOIN condition for tagging.' );
 648                 }
 649
 650                 $fields['ts_tags'] = wfGetDB( DB_REPLICA )->buildGroupConcatField(
 651                         ',', 'change_tag', 'ct_tag', $join_cond
 652                 );
 653
 654                 if ( $wgUseTagFilter && $filter_tag ) {
 655                         // Somebody wants to filter on a tag.
 656                         // Add an INNER JOIN on change_tag
 657
 658                         $tables[] = 'change_tag';
 659                         $join_conds['change_tag'] = [ 'INNER JOIN', $join_cond ];
 660                         $conds['ct_tag'] = $filter_tag;
 661                 }
 662         }
 663
 664         /**
 665          * Build a text box to select a change tag
 666          *
 667          * @param string $selected Tag to select by default
 668          * @param bool $ooui Use an OOUI TextInputWidget as selector instead of a non-OOUI input field
 669          *        You need to call OutputPage::enableOOUI() yourself.
 670          * @return array an array of (label, selector)
 671          */
 672         public static function buildTagFilterSelector( $selected = '', $ooui = false ) {
 673                 global $wgUseTagFilter;
 674
 675                 if ( !$wgUseTagFilter || !count( self::listDefinedTags() ) ) {
 676                         return [];
 677                 }
 678
 679                 $data = [
 680                         Html::rawElement(
 681                                 'label',
 682                                 [ 'for' => 'tagfilter' ],
 683                                 wfMessage( 'tag-filter' )->parse()
 684                         )
 685                 ];
 686
 687                 if ( $ooui ) {
 688                         $data[] = new OOUI\TextInputWidget( [
 689                                 'id' => 'tagfilter',
 690                                 'name' => 'tagfilter',
 691                                 'value' => $selected,
 692                                 'classes' => 'mw-tagfilter-input',
 693                         ] );
 694                 } else {
 695                         $data[] = Xml::input(
 696                                 'tagfilter',
 697                                 20,
 698                                 $selected,
 699                                 [ 'class' => 'mw-tagfilter-input mw-ui-input mw-ui-input-inline', 'id' => 'tagfilter' ]
 700                         );
 701                 }
 702
 703                 return $data;
 704         }
 705
 706         /**
 707          * Defines a tag in the valid_tag table, without checking that the tag name
 708          * is valid.
 709          * Extensions should NOT use this function; they can use the ListDefinedTags
 710          * hook instead.
 711          *
 712          * @param string $tag Tag to create
 713          * @since 1.25
 714          */
 715         public static function defineTag( $tag ) {
 716                 $dbw = wfGetDB( DB_MASTER );
 717                 $dbw->replace( 'valid_tag',
 718                         [ 'vt_tag' ],
 719                         [ 'vt_tag' => $tag ],
 720                         __METHOD__ );
 721
 722                 // clear the memcache of defined tags
 723                 self::purgeTagCacheAll();
 724         }
 725
 726         /**
 727          * Removes a tag from the valid_tag table. The tag may remain in use by
 728          * extensions, and may still show up as 'defined' if an extension is setting
 729          * it from the ListDefinedTags hook.
 730          *
 731          * @param string $tag Tag to remove
 732          * @since 1.25
 733          */
 734         public static function undefineTag( $tag ) {
 735                 $dbw = wfGetDB( DB_MASTER );
 736                 $dbw->delete( 'valid_tag', [ 'vt_tag' => $tag ], __METHOD__ );
 737
 738                 // clear the memcache of defined tags
 739                 self::purgeTagCacheAll();
 740         }
 741
 742         /**
 743          * Writes a tag action into the tag management log.
 744          *
 745          * @param string $action
 746          * @param string $tag
 747          * @param string $reason
 748          * @param User $user Who to attribute the action to
 749          * @param int $tagCount For deletion only, how many usages the tag had before
 750          * it was deleted.
 751          * @return int ID of the inserted log entry
 752          * @since 1.25
 753          */
 754         protected static function logTagManagementAction( $action, $tag, $reason,
 755                 User $user, $tagCount = null ) {
 756
 757                 $dbw = wfGetDB( DB_MASTER );
 758
 759                 $logEntry = new ManualLogEntry( 'managetags', $action );
 760                 $logEntry->setPerformer( $user );
 761                 // target page is not relevant, but it has to be set, so we just put in
 762                 // the title of Special:Tags
 763                 $logEntry->setTarget( Title::newFromText( 'Special:Tags' ) );
 764                 $logEntry->setComment( $reason );
 765
 766                 $params = [ '4::tag' => $tag ];
 767                 if ( !is_null( $tagCount ) ) {
 768                         $params['5:number:count'] = $tagCount;
 769                 }
 770                 $logEntry->setParameters( $params );
 771                 $logEntry->setRelations( [ 'Tag' => $tag ] );
 772
 773                 $logId = $logEntry->insert( $dbw );
 774                 $logEntry->publish( $logId );
 775                 return $logId;
 776         }
 777
 778         /**
 779          * Is it OK to allow the user to activate this tag?
 780          *
 781          * @param string $tag Tag that you are interested in activating
 782          * @param User|null $user User whose permission you wish to check, or null if
 783          * you don't care (e.g. maintenance scripts)
 784          * @return Status
 785          * @since 1.25
 786          */
 787         public static function canActivateTag( $tag, User $user = null ) {
 788                 if ( !is_null( $user ) ) {
 789                         if ( !$user->isAllowed( 'managechangetags' ) ) {
 790                                 return Status::newFatal( 'tags-manage-no-permission' );
 791                         } elseif ( $user->isBlocked() ) {
 792                                 return Status::newFatal( 'tags-manage-blocked' );
 793                         }
 794                 }
 795
 796                 // defined tags cannot be activated (a defined tag is either extension-
 797                 // defined, in which case the extension chooses whether or not to active it;
 798                 // or user-defined, in which case it is considered active)
 799                 $definedTags = self::listDefinedTags();
 800                 if ( in_array( $tag, $definedTags ) ) {
 801                         return Status::newFatal( 'tags-activate-not-allowed', $tag );
 802                 }
 803
 804                 // non-existing tags cannot be activated
 805                 $tagUsage = self::tagUsageStatistics();
 806                 if ( !isset( $tagUsage[$tag] ) ) { // we already know the tag is undefined
 807                         return Status::newFatal( 'tags-activate-not-found', $tag );
 808                 }
 809
 810                 return Status::newGood();
 811         }
 812
 813         /**
 814          * Activates a tag, checking whether it is allowed first, and adding a log
 815          * entry afterwards.
 816          *
 817          * Includes a call to ChangeTag::canActivateTag(), so your code doesn't need
 818          * to do that.
 819          *
 820          * @param string $tag
 821          * @param string $reason
 822          * @param User $user Who to give credit for the action
 823          * @param bool $ignoreWarnings Can be used for API interaction, default false
 824          * @return Status If successful, the Status contains the ID of the added log
 825          * entry as its value
 826          * @since 1.25
 827          */
 828         public static function activateTagWithChecks( $tag, $reason, User $user,
 829                 $ignoreWarnings = false ) {
 830
 831                 // are we allowed to do this?
 832                 $result = self::canActivateTag( $tag, $user );
 833                 if ( $ignoreWarnings ? !$result->isOK() : !$result->isGood() ) {
 834                         $result->value = null;
 835                         return $result;
 836                 }
 837
 838                 // do it!
 839                 self::defineTag( $tag );
 840
 841                 // log it
 842                 $logId = self::logTagManagementAction( 'activate', $tag, $reason, $user );
 843                 return Status::newGood( $logId );
 844         }
 845
 846         /**
 847          * Is it OK to allow the user to deactivate this tag?
 848          *
 849          * @param string $tag Tag that you are interested in deactivating
 850          * @param User|null $user User whose permission you wish to check, or null if
 851          * you don't care (e.g. maintenance scripts)
 852          * @return Status
 853          * @since 1.25
 854          */
 855         public static function canDeactivateTag( $tag, User $user = null ) {
 856                 if ( !is_null( $user ) ) {
 857                         if ( !$user->isAllowed( 'managechangetags' ) ) {
 858                                 return Status::newFatal( 'tags-manage-no-permission' );
 859                         } elseif ( $user->isBlocked() ) {
 860                                 return Status::newFatal( 'tags-manage-blocked' );
 861                         }
 862                 }
 863
 864                 // only explicitly-defined tags can be deactivated
 865                 $explicitlyDefinedTags = self::listExplicitlyDefinedTags();
 866                 if ( !in_array( $tag, $explicitlyDefinedTags ) ) {
 867                         return Status::newFatal( 'tags-deactivate-not-allowed', $tag );
 868                 }
 869                 return Status::newGood();
 870         }
 871
 872         /**
 873          * Deactivates a tag, checking whether it is allowed first, and adding a log
 874          * entry afterwards.
 875          *
 876          * Includes a call to ChangeTag::canDeactivateTag(), so your code doesn't need
 877          * to do that.
 878          *
 879          * @param string $tag
 880          * @param string $reason
 881          * @param User $user Who to give credit for the action
 882          * @param bool $ignoreWarnings Can be used for API interaction, default false
 883          * @return Status If successful, the Status contains the ID of the added log
 884          * entry as its value
 885          * @since 1.25
 886          */
 887         public static function deactivateTagWithChecks( $tag, $reason, User $user,
 888                 $ignoreWarnings = false ) {
 889
 890                 // are we allowed to do this?
 891                 $result = self::canDeactivateTag( $tag, $user );
 892                 if ( $ignoreWarnings ? !$result->isOK() : !$result->isGood() ) {
 893                         $result->value = null;
 894                         return $result;
 895                 }
 896
 897                 // do it!
 898                 self::undefineTag( $tag );
 899
 900                 // log it
 901                 $logId = self::logTagManagementAction( 'deactivate', $tag, $reason, $user );
 902                 return Status::newGood( $logId );
 903         }
 904
 905         /**
 906          * Is it OK to allow the user to create this tag?
 907          *
 908          * @param string $tag Tag that you are interested in creating
 909          * @param User|null $user User whose permission you wish to check, or null if
 910          * you don't care (e.g. maintenance scripts)
 911          * @return Status
 912          * @since 1.25
 913          */
 914         public static function canCreateTag( $tag, User $user = null ) {
 915                 if ( !is_null( $user ) ) {
 916                         if ( !$user->isAllowed( 'managechangetags' ) ) {
 917                                 return Status::newFatal( 'tags-manage-no-permission' );
 918                         } elseif ( $user->isBlocked() ) {
 919                                 return Status::newFatal( 'tags-manage-blocked' );
 920                         }
 921                 }
 922
 923                 // no empty tags
 924                 if ( $tag === '' ) {
 925                         return Status::newFatal( 'tags-create-no-name' );
 926                 }
 927
 928                 // tags cannot contain commas (used as a delimiter in tag_summary table) or
 929                 // slashes (would break tag description messages in MediaWiki namespace)
 930                 if ( strpos( $tag, ',' ) !== false || strpos( $tag, '/' ) !== false ) {
 931                         return Status::newFatal( 'tags-create-invalid-chars' );
 932                 }
 933
 934                 // could the MediaWiki namespace description messages be created?
 935                 $title = Title::makeTitleSafe( NS_MEDIAWIKI, "Tag-$tag-description" );
 936                 if ( is_null( $title ) ) {
 937                         return Status::newFatal( 'tags-create-invalid-title-chars' );
 938                 }
 939
 940                 // does the tag already exist?
 941                 $tagUsage = self::tagUsageStatistics();
 942                 if ( isset( $tagUsage[$tag] ) || in_array( $tag, self::listDefinedTags() ) ) {
 943                         return Status::newFatal( 'tags-create-already-exists', $tag );
 944                 }
 945
 946                 // check with hooks
 947                 $canCreateResult = Status::newGood();
 948                 Hooks::run( 'ChangeTagCanCreate', [ $tag, $user, &$canCreateResult ] );
 949                 return $canCreateResult;
 950         }
 951
 952         /**
 953          * Creates a tag by adding a row to the `valid_tag` table.
 954          *
 955          * Includes a call to ChangeTag::canDeleteTag(), so your code doesn't need to
 956          * do that.
 957          *
 958          * @param string $tag
 959          * @param string $reason
 960          * @param User $user Who to give credit for the action
 961          * @param bool $ignoreWarnings Can be used for API interaction, default false
 962          * @return Status If successful, the Status contains the ID of the added log
 963          * entry as its value
 964          * @since 1.25
 965          */
 966         public static function createTagWithChecks( $tag, $reason, User $user,
 967                 $ignoreWarnings = false ) {
 968
 969                 // are we allowed to do this?
 970                 $result = self::canCreateTag( $tag, $user );
 971                 if ( $ignoreWarnings ? !$result->isOK() : !$result->isGood() ) {
 972                         $result->value = null;
 973                         return $result;
 974                 }
 975
 976                 // do it!
 977                 self::defineTag( $tag );
 978
 979                 // log it
 980                 $logId = self::logTagManagementAction( 'create', $tag, $reason, $user );
 981                 return Status::newGood( $logId );
 982         }
 983
 984         /**
 985          * Permanently removes all traces of a tag from the DB. Good for removing
 986          * misspelt or temporary tags.
 987          *
 988          * This function should be directly called by maintenance scripts only, never
 989          * by user-facing code. See deleteTagWithChecks() for functionality that can
 990          * safely be exposed to users.
 991          *
 992          * @param string $tag Tag to remove
 993          * @return Status The returned status will be good unless a hook changed it
 994          * @since 1.25
 995          */
 996         public static function deleteTagEverywhere( $tag ) {
 997                 $dbw = wfGetDB( DB_MASTER );
 998                 $dbw->startAtomic( __METHOD__ );
 999
1000                 // delete from valid_tag
1001                 self::undefineTag( $tag );
1002
1003                 // find out which revisions use this tag, so we can delete from tag_summary
1004                 $result = $dbw->select( 'change_tag',
1005                         [ 'ct_rc_id', 'ct_log_id', 'ct_rev_id', 'ct_tag' ],
1006                         [ 'ct_tag' => $tag ],
1007                         __METHOD__ );
1008                 foreach ( $result as $row ) {
1009                         // remove the tag from the relevant row of tag_summary
1010                         $tagsToAdd = [];
1011                         $tagsToRemove = [ $tag ];
1012                         self::updateTagSummaryRow( $tagsToAdd, $tagsToRemove, $row->ct_rc_id,
1013                                 $row->ct_rev_id, $row->ct_log_id );
1014                 }
1015
1016                 // delete from change_tag
1017                 $dbw->delete( 'change_tag', [ 'ct_tag' => $tag ], __METHOD__ );
1018
1019                 $dbw->endAtomic( __METHOD__ );
1020
1021                 // give extensions a chance
1022                 $status = Status::newGood();
1023                 Hooks::run( 'ChangeTagAfterDelete', [ $tag, &$status ] );
1024                 // let's not allow error results, as the actual tag deletion succeeded
1025                 if ( !$status->isOK() ) {
1026                         wfDebug( 'ChangeTagAfterDelete error condition downgraded to warning' );
1027                         $status->setOK( true );
1028                 }
1029
1030                 // clear the memcache of defined tags
1031                 self::purgeTagCacheAll();
1032
1033                 return $status;
1034         }
1035
1036         /**
1037          * Is it OK to allow the user to delete this tag?
1038          *
1039          * @param string $tag Tag that you are interested in deleting
1040          * @param User|null $user User whose permission you wish to check, or null if
1041          * you don't care (e.g. maintenance scripts)
1042          * @return Status
1043          * @since 1.25
1044          */
1045         public static function canDeleteTag( $tag, User $user = null ) {
1046                 $tagUsage = self::tagUsageStatistics();
1047
1048                 if ( !is_null( $user ) ) {
1049                         if ( !$user->isAllowed( 'deletechangetags' ) ) {
1050                                 return Status::newFatal( 'tags-delete-no-permission' );
1051                         } elseif ( $user->isBlocked() ) {
1052                                 return Status::newFatal( 'tags-manage-blocked' );
1053                         }
1054                 }
1055
1056                 if ( !isset( $tagUsage[$tag] ) && !in_array( $tag, self::listDefinedTags() ) ) {
1057                         return Status::newFatal( 'tags-delete-not-found', $tag );
1058                 }
1059
1060                 if ( isset( $tagUsage[$tag] ) && $tagUsage[$tag] > self::MAX_DELETE_USES ) {
1061                         return Status::newFatal( 'tags-delete-too-many-uses', $tag, self::MAX_DELETE_USES );
1062                 }
1063
1064                 $softwareDefined = self::listSoftwareDefinedTags();
1065                 if ( in_array( $tag, $softwareDefined ) ) {
1066                         // extension-defined tags can't be deleted unless the extension
1067                         // specifically allows it
1068                         $status = Status::newFatal( 'tags-delete-not-allowed' );
1069                 } else {
1070                         // user-defined tags are deletable unless otherwise specified
1071                         $status = Status::newGood();
1072                 }
1073
1074                 Hooks::run( 'ChangeTagCanDelete', [ $tag, $user, &$status ] );
1075                 return $status;
1076         }
1077
1078         /**
1079          * Deletes a tag, checking whether it is allowed first, and adding a log entry
1080          * afterwards.
1081          *
1082          * Includes a call to ChangeTag::canDeleteTag(), so your code doesn't need to
1083          * do that.
1084          *
1085          * @param string $tag
1086          * @param string $reason
1087          * @param User $user Who to give credit for the action
1088          * @param bool $ignoreWarnings Can be used for API interaction, default false
1089          * @return Status If successful, the Status contains the ID of the added log
1090          * entry as its value
1091          * @since 1.25
1092          */
1093         public static function deleteTagWithChecks( $tag, $reason, User $user,
1094                 $ignoreWarnings = false ) {
1095
1096                 // are we allowed to do this?
1097                 $result = self::canDeleteTag( $tag, $user );
1098                 if ( $ignoreWarnings ? !$result->isOK() : !$result->isGood() ) {
1099                         $result->value = null;
1100                         return $result;
1101                 }
1102
1103                 // store the tag usage statistics
1104                 $tagUsage = self::tagUsageStatistics();
1105                 $hitcount = isset( $tagUsage[$tag] ) ? $tagUsage[$tag] : 0;
1106
1107                 // do it!
1108                 $deleteResult = self::deleteTagEverywhere( $tag );
1109                 if ( !$deleteResult->isOK() ) {
1110                         return $deleteResult;
1111                 }
1112
1113                 // log it
1114                 $logId = self::logTagManagementAction( 'delete', $tag, $reason, $user, $hitcount );
1115                 $deleteResult->value = $logId;
1116                 return $deleteResult;
1117         }
1118
1119         /**
1120          * Lists those tags which core or extensions report as being "active".
1121          *
1122          * @return array
1123          * @since 1.25
1124          */
1125         public static function listSoftwareActivatedTags() {
1126                 // core active tags
1127                 $tags = self::$coreTags;
1128                 if ( !Hooks::isRegistered( 'ChangeTagsListActive' ) ) {
1129                         return $tags;
1130                 }
1131                 return ObjectCache::getMainWANInstance()->getWithSetCallback(
1132                         wfMemcKey( 'active-tags' ),
1133                         WANObjectCache::TTL_MINUTE * 5,
1134                         function ( $oldValue, &$ttl, array &$setOpts ) use ( $tags ) {
1135                                 $setOpts += Database::getCacheSetOptions( wfGetDB( DB_REPLICA ) );
1136
1137                                 // Ask extensions which tags they consider active
1138                                 Hooks::run( 'ChangeTagsListActive', [ &$tags ] );
1139                                 return $tags;
1140                         },
1141                         [
1142                                 'checkKeys' => [ wfMemcKey( 'active-tags' ) ],
1143                                 'lockTSE' => WANObjectCache::TTL_MINUTE * 5,
1144                                 'pcTTL' => WANObjectCache::TTL_PROC_LONG
1145                         ]
1146                 );
1147         }
1148
1149         /**
1150          * @see listSoftwareActivatedTags
1151          * @deprecated since 1.28 call listSoftwareActivatedTags directly
1152          * @return array
1153          */
1154         public static function listExtensionActivatedTags() {
1155                 wfDeprecated( __METHOD__, '1.28' );
1156                 return self::listSoftwareActivatedTags();
1157         }
1158
1159         /**
1160          * Basically lists defined tags which count even if they aren't applied to anything.
1161          * It returns a union of the results of listExplicitlyDefinedTags() and
1162          * listExtensionDefinedTags().
1163          *
1164          * @return string[] Array of strings: tags
1165          */
1166         public static function listDefinedTags() {
1167                 $tags1 = self::listExplicitlyDefinedTags();
1168                 $tags2 = self::listSoftwareDefinedTags();
1169                 return array_values( array_unique( array_merge( $tags1, $tags2 ) ) );
1170         }
1171
1172         /**
1173          * Lists tags explicitly defined in the `valid_tag` table of the database.
1174          * Tags in table 'change_tag' which are not in table 'valid_tag' are not
1175          * included.
1176          *
1177          * Tries memcached first.
1178          *
1179          * @return string[] Array of strings: tags
1180          * @since 1.25
1181          */
1182         public static function listExplicitlyDefinedTags() {
1183                 $fname = __METHOD__;
1184
1185                 return ObjectCache::getMainWANInstance()->getWithSetCallback(
1186                         wfMemcKey( 'valid-tags-db' ),
1187                         WANObjectCache::TTL_MINUTE * 5,
1188                         function ( $oldValue, &$ttl, array &$setOpts ) use ( $fname ) {
1189                                 $dbr = wfGetDB( DB_REPLICA );
1190
1191                                 $setOpts += Database::getCacheSetOptions( $dbr );
1192
1193                                 $tags = $dbr->selectFieldValues( 'valid_tag', 'vt_tag', [], $fname );
1194
1195                                 return array_filter( array_unique( $tags ) );
1196                         },
1197                         [
1198                                 'checkKeys' => [ wfMemcKey( 'valid-tags-db' ) ],
1199                                 'lockTSE' => WANObjectCache::TTL_MINUTE * 5,
1200                                 'pcTTL' => WANObjectCache::TTL_PROC_LONG
1201                         ]
1202                 );
1203         }
1204
1205         /**
1206          * Lists tags defined by core or extensions using the ListDefinedTags hook.
1207          * Extensions need only define those tags they deem to be in active use.
1208          *
1209          * Tries memcached first.
1210          *
1211          * @return string[] Array of strings: tags
1212          * @since 1.25
1213          */
1214         public static function listSoftwareDefinedTags() {
1215                 // core defined tags
1216                 $tags = self::$coreTags;
1217                 if ( !Hooks::isRegistered( 'ListDefinedTags' ) ) {
1218                         return $tags;
1219                 }
1220                 return ObjectCache::getMainWANInstance()->getWithSetCallback(
1221                         wfMemcKey( 'valid-tags-hook' ),
1222                         WANObjectCache::TTL_MINUTE * 5,
1223                         function ( $oldValue, &$ttl, array &$setOpts ) use ( $tags ) {
1224                                 $setOpts += Database::getCacheSetOptions( wfGetDB( DB_REPLICA ) );
1225
1226                                 Hooks::run( 'ListDefinedTags', [ &$tags ] );
1227                                 return array_filter( array_unique( $tags ) );
1228                         },
1229                         [
1230                                 'checkKeys' => [ wfMemcKey( 'valid-tags-hook' ) ],
1231                                 'lockTSE' => WANObjectCache::TTL_MINUTE * 5,
1232                                 'pcTTL' => WANObjectCache::TTL_PROC_LONG
1233                         ]
1234                 );
1235         }
1236
1237         /**
1238          * Call listSoftwareDefinedTags directly
1239          *
1240          * @see listSoftwareDefinedTags
1241          * @deprecated since 1.28
1242          */
1243         public static function listExtensionDefinedTags() {
1244                 wfDeprecated( __METHOD__, '1.28' );
1245                 return self::listSoftwareDefinedTags();
1246         }
1247
1248         /**
1249          * Invalidates the short-term cache of defined tags used by the
1250          * list*DefinedTags functions, as well as the tag statistics cache.
1251          * @since 1.25
1252          */
1253         public static function purgeTagCacheAll() {
1254                 $cache = ObjectCache::getMainWANInstance();
1255
1256                 $cache->touchCheckKey( wfMemcKey( 'active-tags' ) );
1257                 $cache->touchCheckKey( wfMemcKey( 'valid-tags-db' ) );
1258                 $cache->touchCheckKey( wfMemcKey( 'valid-tags-hook' ) );
1259
1260                 self::purgeTagUsageCache();
1261         }
1262
1263         /**
1264          * Invalidates the tag statistics cache only.
1265          * @since 1.25
1266          */
1267         public static function purgeTagUsageCache() {
1268                 $cache = ObjectCache::getMainWANInstance();
1269
1270                 $cache->touchCheckKey( wfMemcKey( 'change-tag-statistics' ) );
1271         }
1272
1273         /**
1274          * Returns a map of any tags used on the wiki to number of edits
1275          * tagged with them, ordered descending by the hitcount.
1276          * This does not include tags defined somewhere that have never been applied.
1277          *
1278          * Keeps a short-term cache in memory, so calling this multiple times in the
1279          * same request should be fine.
1280          *
1281          * @return array Array of string => int
1282          */
1283         public static function tagUsageStatistics() {
1284                 $fname = __METHOD__;
1285                 return ObjectCache::getMainWANInstance()->getWithSetCallback(
1286                         wfMemcKey( 'change-tag-statistics' ),
1287                         WANObjectCache::TTL_MINUTE * 5,
1288                         function ( $oldValue, &$ttl, array &$setOpts ) use ( $fname ) {
1289                                 $dbr = wfGetDB( DB_REPLICA, 'vslow' );
1290
1291                                 $setOpts += Database::getCacheSetOptions( $dbr );
1292
1293                                 $res = $dbr->select(
1294                                         'change_tag',
1295                                         [ 'ct_tag', 'hitcount' => 'count(*)' ],
1296                                         [],
1297                                         $fname,
1298                                         [ 'GROUP BY' => 'ct_tag', 'ORDER BY' => 'hitcount DESC' ]
1299                                 );
1300
1301                                 $out = [];
1302                                 foreach ( $res as $row ) {
1303                                         $out[$row->ct_tag] = $row->hitcount;
1304                                 }
1305
1306                                 return $out;
1307                         },
1308                         [
1309                                 'checkKeys' => [ wfMemcKey( 'change-tag-statistics' ) ],
1310                                 'lockTSE' => WANObjectCache::TTL_MINUTE * 5,
1311                                 'pcTTL' => WANObjectCache::TTL_PROC_LONG
1312                         ]
1313                 );
1314         }
1315
1316         /**
1317          * Indicate whether change tag editing UI is relevant
1318          *
1319          * Returns true if the user has the necessary right and there are any
1320          * editable tags defined.
1321          *
1322          * This intentionally doesn't check "any addable || any deletable", because
1323          * it seems like it would be more confusing than useful if the checkboxes
1324          * suddenly showed up because some abuse filter stopped defining a tag and
1325          * then suddenly disappeared when someone deleted all uses of that tag.
1326          *
1327          * @param User $user
1328          * @return bool
1329          */
1330         public static function showTagEditingUI( User $user ) {
1331                 return $user->isAllowed( 'changetags' ) && (bool)self::listExplicitlyDefinedTags();
1332         }
1333 }