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 use MediaWiki\MediaWikiServices;
  25 use MediaWiki\Storage\NameTableAccessException;
  26 use Wikimedia\Rdbms\Database;
  27 use Wikimedia\Rdbms\IDatabase;
  28
  29 class ChangeTags {
  30         /**
  31          * Can't delete tags with more than this many uses. Similar in intent to
  32          * the bigdelete user right
  33          * @todo Use the job queue for tag deletion to avoid this restriction
  34          */
  35         const MAX_DELETE_USES = 5000;
  36
  37         /**
  38          * A list of tags defined and used by MediaWiki itself.
  39          */
  40         private static $definedSoftwareTags = [
  41                 'mw-contentmodelchange',
  42                 'mw-new-redirect',
  43                 'mw-removed-redirect',
  44                 'mw-changed-redirect-target',
  45                 'mw-blank',
  46                 'mw-replace',
  47                 'mw-rollback',
  48                 'mw-undo',
  49         ];
  50
  51         /**
  52          * Loads defined core tags, checks for invalid types (if not array),
  53          * and filters for supported and enabled (if $all is false) tags only.
  54          *
  55          * @param bool $all If true, return all valid defined tags. Otherwise, return only enabled ones.
  56          * @return array Array of all defined/enabled tags.
  57          */
  58         public static function getSoftwareTags( $all = false ) {
  59                 global $wgSoftwareTags;
  60                 $softwareTags = [];
  61
  62                 if ( !is_array( $wgSoftwareTags ) ) {
  63                         wfWarn( 'wgSoftwareTags should be associative array of enabled tags.
  64                         Please refer to documentation for the list of tags you can enable' );
  65                         return $softwareTags;
  66                 }
  67
  68                 $availableSoftwareTags = !$all ?
  69                         array_keys( array_filter( $wgSoftwareTags ) ) :
  70                         array_keys( $wgSoftwareTags );
  71
  72                 $softwareTags = array_intersect(
  73                         $availableSoftwareTags,
  74                         self::$definedSoftwareTags
  75                 );
  76
  77                 return $softwareTags;
  78         }
  79
  80         /**
  81          * Creates HTML for the given tags
  82          *
  83          * @param string $tags Comma-separated list of tags
  84          * @param string $page A label for the type of action which is being displayed,
  85          *   for example: 'history', 'contributions' or 'newpages'
  86          * @param IContextSource|null $context
  87          * @note Even though it takes null as a valid argument, an IContextSource is preferred
  88          *       in a new code, as the null value is subject to change in the future
  89          * @return array Array with two items: (html, classes)
  90          *   - html: String: HTML for displaying the tags (empty string when param $tags is empty)
  91          *   - classes: Array of strings: CSS classes used in the generated html, one class for each tag
  92          * @return-taint onlysafefor_htmlnoent
  93          */
  94         public static function formatSummaryRow( $tags, $page, IContextSource $context = null ) {
  95                 if ( !$tags ) {
  96                         return [ '', [] ];
  97                 }
  98                 if ( !$context ) {
  99                         $context = RequestContext::getMain();
 100                 }
 101
 102                 $classes = [];
 103
 104                 $tags = explode( ',', $tags );
 105                 $displayTags = [];
 106                 foreach ( $tags as $tag ) {
 107                         if ( !$tag ) {
 108                                 continue;
 109                         }
 110                         $description = self::tagDescription( $tag, $context );
 111                         if ( $description === false ) {
 112                                 continue;
 113                         }
 114                         $displayTags[] = Xml::tags(
 115                                 'span',
 116                                 [ 'class' => 'mw-tag-marker ' .
 117                                                                 Sanitizer::escapeClass( "mw-tag-marker-$tag" ) ],
 118                                 $description
 119                         );
 120                         $classes[] = Sanitizer::escapeClass( "mw-tag-$tag" );
 121                 }
 122
 123                 if ( !$displayTags ) {
 124                         return [ '', [] ];
 125                 }
 126
 127                 $markers = $context->msg( 'tag-list-wrapper' )
 128                         ->numParams( count( $displayTags ) )
 129                         ->rawParams( implode( ' ',  $displayTags ) )
 130                         ->parse();
 131                 $markers = Xml::tags( 'span', [ 'class' => 'mw-tag-markers' ], $markers );
 132
 133                 return [ $markers, $classes ];
 134         }
 135
 136         /**
 137          * Get the message object for the tag's short description.
 138          *
 139          * Checks if message key "mediawiki:tag-$tag" exists. If it does not,
 140          * returns the tag name in a RawMessage. If the message exists, it is
 141          * used, provided it is not disabled. If the message is disabled, we
 142          * consider the tag hidden, and return false.
 143          *
 144          * @since 1.34
 145          * @param string $tag
 146          * @param MessageLocalizer $context
 147          * @return Message|bool Tag description, or false if tag is to be hidden.
 148          */
 149         public static function tagShortDescriptionMessage( $tag, MessageLocalizer $context ) {
 150                 $msg = $context->msg( "tag-$tag" );
 151                 if ( !$msg->exists() ) {
 152                         // No such message
 153                         return ( new RawMessage( '$1', [ Message::plaintextParam( $tag ) ] ) )
 154                                 // HACK MessageLocalizer doesn't have a way to set the right language on a RawMessage,
 155                                 // so extract the language from $msg and use that.
 156                                 // The language doesn't really matter, but we need to set it to avoid requesting
 157                                 // the user's language from session-less entry points (T227233)
 158                                 ->inLanguage( $msg->getLanguage() );
 159
 160                 }
 161                 if ( $msg->isDisabled() ) {
 162                         // The message exists but is disabled, hide the tag.
 163                         return false;
 164                 }
 165
 166                 // Message exists and isn't disabled, use it.
 167                 return $msg;
 168         }
 169
 170         /**
 171          * Get a short description for a tag.
 172          *
 173          * Checks if message key "mediawiki:tag-$tag" exists. If it does not,
 174          * returns the HTML-escaped tag name. Uses the message if the message
 175          * exists, provided it is not disabled. If the message is disabled,
 176          * we consider the tag hidden, and return false.
 177          *
 178          * @param string $tag
 179          * @param MessageLocalizer $context
 180          * @return string|bool Tag description or false if tag is to be hidden.
 181          * @since 1.25 Returns false if tag is to be hidden.
 182          */
 183         public static function tagDescription( $tag, MessageLocalizer $context ) {
 184                 $msg = self::tagShortDescriptionMessage( $tag, $context );
 185                 return $msg ? $msg->parse() : false;
 186         }
 187
 188         /**
 189          * Get the message object for the tag's long description.
 190          *
 191          * Checks if message key "mediawiki:tag-$tag-description" exists. If it does not,
 192          * or if message is disabled, returns false. Otherwise, returns the message object
 193          * for the long description.
 194          *
 195          * @param string $tag
 196          * @param MessageLocalizer $context
 197          * @return Message|bool Message object of the tag long description or false if
 198          *  there is no description.
 199          */
 200         public static function tagLongDescriptionMessage( $tag, MessageLocalizer $context ) {
 201                 $msg = $context->msg( "tag-$tag-description" );
 202                 if ( !$msg->exists() ) {
 203                         return false;
 204                 }
 205                 if ( $msg->isDisabled() ) {
 206                         // The message exists but is disabled, hide the description.
 207                         return false;
 208                 }
 209
 210                 // Message exists and isn't disabled, use it.
 211                 return $msg;
 212         }
 213
 214         /**
 215          * Get truncated message for the tag's long description.
 216          *
 217          * @param string $tag Tag name.
 218          * @param int $length Maximum length of truncated message, including ellipsis.
 219          * @param IContextSource $context
 220          *
 221          * @return string Truncated long tag description.
 222          */
 223         public static function truncateTagDescription( $tag, $length, IContextSource $context ) {
 224                 // FIXME: Make this accept MessageLocalizer and Language instead of IContextSource
 225
 226                 $originalDesc = self::tagLongDescriptionMessage( $tag, $context );
 227                 // If there is no tag description, return empty string
 228                 if ( !$originalDesc ) {
 229                         return '';
 230                 }
 231
 232                 $taglessDesc = Sanitizer::stripAllTags( $originalDesc->parse() );
 233
 234                 return $context->getLanguage()->truncateForVisual( $taglessDesc, $length );
 235         }
 236
 237         /**
 238          * Add tags to a change given its rc_id, rev_id and/or log_id
 239          *
 240          * @param string|string[] $tags Tags to add to the change
 241          * @param int|null $rc_id The rc_id of the change to add the tags to
 242          * @param int|null $rev_id The rev_id of the change to add the tags to
 243          * @param int|null $log_id The log_id of the change to add the tags to
 244          * @param string|null $params Params to put in the ct_params field of table 'change_tag'
 245          * @param RecentChange|null $rc Recent change, in case the tagging accompanies the action
 246          * (this should normally be the case)
 247          *
 248          * @throws MWException
 249          * @return bool False if no changes are made, otherwise true
 250          */
 251         public static function addTags( $tags, $rc_id = null, $rev_id = null,
 252                 $log_id = null, $params = null, RecentChange $rc = null
 253         ) {
 254                 $result = self::updateTags( $tags, null, $rc_id, $rev_id, $log_id, $params, $rc );
 255                 return (bool)$result[0];
 256         }
 257
 258         /**
 259          * Add and remove tags to/from a change given its rc_id, rev_id and/or log_id,
 260          * without verifying that the tags exist or are valid. If a tag is present in
 261          * both $tagsToAdd and $tagsToRemove, it will be removed.
 262          *
 263          * This function should only be used by extensions to manipulate tags they
 264          * have registered using the ListDefinedTags hook. When dealing with user
 265          * input, call updateTagsWithChecks() instead.
 266          *
 267          * @param string|array|null $tagsToAdd Tags to add to the change
 268          * @param string|array|null $tagsToRemove Tags to remove from the change
 269          * @param int|null &$rc_id The rc_id of the change to add the tags to.
 270          * Pass a variable whose value is null if the rc_id is not relevant or unknown.
 271          * @param int|null &$rev_id The rev_id of the change to add the tags to.
 272          * Pass a variable whose value is null if the rev_id is not relevant or unknown.
 273          * @param int|null &$log_id The log_id of the change to add the tags to.
 274          * Pass a variable whose value is null if the log_id is not relevant or unknown.
 275          * @param string|null $params Params to put in the ct_params field of table
 276          * 'change_tag' when adding tags
 277          * @param RecentChange|null $rc Recent change being tagged, in case the tagging accompanies
 278          * the action
 279          * @param User|null $user Tagging user, in case the tagging is subsequent to the tagged action
 280          *
 281          * @throws MWException When $rc_id, $rev_id and $log_id are all null
 282          * @return array Index 0 is an array of tags actually added, index 1 is an
 283          * array of tags actually removed, index 2 is an array of tags present on the
 284          * revision or log entry before any changes were made
 285          *
 286          * @since 1.25
 287          */
 288         public static function updateTags( $tagsToAdd, $tagsToRemove, &$rc_id = null,
 289                 &$rev_id = null, &$log_id = null, $params = null, RecentChange $rc = null,
 290                 User $user = null
 291         ) {
 292                 $tagsToAdd = array_filter( (array)$tagsToAdd ); // Make sure we're submitting all tags...
 293                 $tagsToRemove = array_filter( (array)$tagsToRemove );
 294
 295                 if ( !$rc_id && !$rev_id && !$log_id ) {
 296                         throw new MWException( 'At least one of: RCID, revision ID, and log ID MUST be ' .
 297                                 'specified when adding or removing a tag from a change!' );
 298                 }
 299
 300                 $dbw = wfGetDB( DB_MASTER );
 301
 302                 // Might as well look for rcids and so on.
 303                 if ( !$rc_id ) {
 304                         // Info might be out of date, somewhat fractionally, on replica DB.
 305                         // LogEntry/LogPage and WikiPage match rev/log/rc timestamps,
 306                         // so use that relation to avoid full table scans.
 307                         if ( $log_id ) {
 308                                 $rc_id = $dbw->selectField(
 309                                         [ 'logging', 'recentchanges' ],
 310                                         'rc_id',
 311                                         [
 312                                                 'log_id' => $log_id,
 313                                                 'rc_timestamp = log_timestamp',
 314                                                 'rc_logid = log_id'
 315                                         ],
 316                                         __METHOD__
 317                                 );
 318                         } elseif ( $rev_id ) {
 319                                 $rc_id = $dbw->selectField(
 320                                         [ 'revision', 'recentchanges' ],
 321                                         'rc_id',
 322                                         [
 323                                                 'rev_id' => $rev_id,
 324                                                 'rc_timestamp = rev_timestamp',
 325                                                 'rc_this_oldid = rev_id'
 326                                         ],
 327                                         __METHOD__
 328                                 );
 329                         }
 330                 } elseif ( !$log_id && !$rev_id ) {
 331                         // Info might be out of date, somewhat fractionally, on replica DB.
 332                         $log_id = $dbw->selectField(
 333                                 'recentchanges',
 334                                 'rc_logid',
 335                                 [ 'rc_id' => $rc_id ],
 336                                 __METHOD__
 337                         );
 338                         $rev_id = $dbw->selectField(
 339                                 'recentchanges',
 340                                 'rc_this_oldid',
 341                                 [ 'rc_id' => $rc_id ],
 342                                 __METHOD__
 343                         );
 344                 }
 345
 346                 if ( $log_id && !$rev_id ) {
 347                         $rev_id = $dbw->selectField(
 348                                 'log_search',
 349                                 'ls_value',
 350                                 [ 'ls_field' => 'associated_rev_id', 'ls_log_id' => $log_id ],
 351                                 __METHOD__
 352                         );
 353                 } elseif ( !$log_id && $rev_id ) {
 354                         $log_id = $dbw->selectField(
 355                                 'log_search',
 356                                 'ls_log_id',
 357                                 [ 'ls_field' => 'associated_rev_id', 'ls_value' => $rev_id ],
 358                                 __METHOD__
 359                         );
 360                 }
 361
 362                 $prevTags = self::getTags( $dbw, $rc_id, $rev_id, $log_id );
 363
 364                 // add tags
 365                 $tagsToAdd = array_values( array_diff( $tagsToAdd, $prevTags ) );
 366                 $newTags = array_unique( array_merge( $prevTags, $tagsToAdd ) );
 367
 368                 // remove tags
 369                 $tagsToRemove = array_values( array_intersect( $tagsToRemove, $newTags ) );
 370                 $newTags = array_values( array_diff( $newTags, $tagsToRemove ) );
 371
 372                 sort( $prevTags );
 373                 sort( $newTags );
 374                 if ( $prevTags == $newTags ) {
 375                         return [ [], [], $prevTags ];
 376                 }
 377
 378                 // insert a row into change_tag for each new tag
 379                 $changeTagDefStore = MediaWikiServices::getInstance()->getChangeTagDefStore();
 380                 if ( count( $tagsToAdd ) ) {
 381                         $changeTagMapping = [];
 382                         foreach ( $tagsToAdd as $tag ) {
 383                                 $changeTagMapping[$tag] = $changeTagDefStore->acquireId( $tag );
 384                         }
 385                         $fname = __METHOD__;
 386                         // T207881: update the counts at the end of the transaction
 387                         $dbw->onTransactionPreCommitOrIdle( function () use ( $dbw, $tagsToAdd, $fname ) {
 388                                 $dbw->update(
 389                                         'change_tag_def',
 390                                         [ 'ctd_count = ctd_count + 1' ],
 391                                         [ 'ctd_name' => $tagsToAdd ],
 392                                         $fname
 393                                 );
 394                         } );
 395
 396                         $tagsRows = [];
 397                         foreach ( $tagsToAdd as $tag ) {
 398                                 // Filter so we don't insert NULLs as zero accidentally.
 399                                 // Keep in mind that $rc_id === null means "I don't care/know about the
 400                                 // rc_id, just delete $tag on this revision/log entry". It doesn't
 401                                 // mean "only delete tags on this revision/log WHERE rc_id IS NULL".
 402                                 $tagsRows[] = array_filter(
 403                                         [
 404                                                 'ct_rc_id' => $rc_id,
 405                                                 'ct_log_id' => $log_id,
 406                                                 'ct_rev_id' => $rev_id,
 407                                                 'ct_params' => $params,
 408                                                 'ct_tag_id' => $changeTagMapping[$tag] ?? null,
 409                                         ]
 410                                 );
 411
 412                         }
 413
 414                         $dbw->insert( 'change_tag', $tagsRows, __METHOD__, [ 'IGNORE' ] );
 415                 }
 416
 417                 // delete from change_tag
 418                 if ( count( $tagsToRemove ) ) {
 419                         $fname = __METHOD__;
 420                         foreach ( $tagsToRemove as $tag ) {
 421                                 $conds = array_filter(
 422                                         [
 423                                                 'ct_rc_id' => $rc_id,
 424                                                 'ct_log_id' => $log_id,
 425                                                 'ct_rev_id' => $rev_id,
 426                                                 'ct_tag_id' => $changeTagDefStore->getId( $tag ),
 427                                         ]
 428                                 );
 429                                 $dbw->delete( 'change_tag', $conds, __METHOD__ );
 430                                 if ( $dbw->affectedRows() ) {
 431                                         // T207881: update the counts at the end of the transaction
 432                                         $dbw->onTransactionPreCommitOrIdle( function () use ( $dbw, $tag, $fname ) {
 433                                                 $dbw->update(
 434                                                         'change_tag_def',
 435                                                         [ 'ctd_count = ctd_count - 1' ],
 436                                                         [ 'ctd_name' => $tag ],
 437                                                         $fname
 438                                                 );
 439
 440                                                 $dbw->delete(
 441                                                         'change_tag_def',
 442                                                         [ 'ctd_name' => $tag, 'ctd_count' => 0, 'ctd_user_defined' => 0 ],
 443                                                         $fname
 444                                                 );
 445                                         } );
 446                                 }
 447                         }
 448                 }
 449
 450                 Hooks::run( 'ChangeTagsAfterUpdateTags', [ $tagsToAdd, $tagsToRemove, $prevTags,
 451                         $rc_id, $rev_id, $log_id, $params, $rc, $user ] );
 452
 453                 return [ $tagsToAdd, $tagsToRemove, $prevTags ];
 454         }
 455
 456         /**
 457          * Return all the tags associated with the given recent change ID,
 458          * revision ID, and/or log entry ID.
 459          *
 460          * @param IDatabase $db the database to query
 461          * @param int|null $rc_id
 462          * @param int|null $rev_id
 463          * @param int|null $log_id
 464          * @return string[]
 465          */
 466         public static function getTags( IDatabase $db, $rc_id = null, $rev_id = null, $log_id = null ) {
 467                 $conds = array_filter(
 468                         [
 469                                 'ct_rc_id' => $rc_id,
 470                                 'ct_rev_id' => $rev_id,
 471                                 'ct_log_id' => $log_id,
 472                         ]
 473                 );
 474
 475                 $tagIds = $db->selectFieldValues(
 476                         'change_tag',
 477                         'ct_tag_id',
 478                         $conds,
 479                         __METHOD__
 480                 );
 481
 482                 $tags = [];
 483                 $changeTagDefStore = MediaWikiServices::getInstance()->getChangeTagDefStore();
 484                 foreach ( $tagIds as $tagId ) {
 485                         $tags[] = $changeTagDefStore->getName( (int)$tagId );
 486                 }
 487
 488                 return $tags;
 489         }
 490
 491         /**
 492          * Helper function to generate a fatal status with a 'not-allowed' type error.
 493          *
 494          * @param string $msgOne Message key to use in the case of one tag
 495          * @param string $msgMulti Message key to use in the case of more than one tag
 496          * @param array $tags Restricted tags (passed as $1 into the message, count of
 497          * $tags passed as $2)
 498          * @return Status
 499          * @since 1.25
 500          */
 501         protected static function restrictedTagError( $msgOne, $msgMulti, $tags ) {
 502                 $lang = RequestContext::getMain()->getLanguage();
 503                 $count = count( $tags );
 504                 return Status::newFatal( ( $count > 1 ) ? $msgMulti : $msgOne,
 505                         $lang->commaList( $tags ), $count );
 506         }
 507
 508         /**
 509          * Is it OK to allow the user to apply all the specified tags at the same time
 510          * as they edit/make the change?
 511          *
 512          * Extensions should not use this function, unless directly handling a user
 513          * request to add a tag to a revision or log entry that the user is making.
 514          *
 515          * @param array $tags Tags that you are interested in applying
 516          * @param User|null $user User whose permission you wish to check, or null to
 517          * check for a generic non-blocked user with the relevant rights
 518          * @return Status
 519          * @since 1.25
 520          */
 521         public static function canAddTagsAccompanyingChange( array $tags, User $user = null ) {
 522                 if ( !is_null( $user ) ) {
 523                         if ( !MediaWikiServices::getInstance()->getPermissionManager()
 524                                         ->userHasRight( $user, 'applychangetags' )
 525                         ) {
 526                                 return Status::newFatal( 'tags-apply-no-permission' );
 527                         } elseif ( $user->getBlock() ) {
 528                                 // @TODO Ensure that the block does not apply to the `applychangetags`
 529                                 //       right.
 530                                 return Status::newFatal( 'tags-apply-blocked', $user->getName() );
 531                         }
 532                 }
 533
 534                 // to be applied, a tag has to be explicitly defined
 535                 $allowedTags = self::listExplicitlyDefinedTags();
 536                 Hooks::run( 'ChangeTagsAllowedAdd', [ &$allowedTags, $tags, $user ] );
 537                 $disallowedTags = array_diff( $tags, $allowedTags );
 538                 if ( $disallowedTags ) {
 539                         return self::restrictedTagError( 'tags-apply-not-allowed-one',
 540                                 'tags-apply-not-allowed-multi', $disallowedTags );
 541                 }
 542
 543                 return Status::newGood();
 544         }
 545
 546         /**
 547          * Adds tags to a given change, checking whether it is allowed first, but
 548          * without adding a log entry. Useful for cases where the tag is being added
 549          * along with the action that generated the change (e.g. tagging an edit as
 550          * it is being made).
 551          *
 552          * Extensions should not use this function, unless directly handling a user
 553          * request to add a particular tag. Normally, extensions should call
 554          * ChangeTags::updateTags() instead.
 555          *
 556          * @param array $tags Tags to apply
 557          * @param int|null $rc_id The rc_id of the change to add the tags to
 558          * @param int|null $rev_id The rev_id of the change to add the tags to
 559          * @param int|null $log_id The log_id of the change to add the tags to
 560          * @param string $params Params to put in the ct_params field of table
 561          * 'change_tag' when adding tags
 562          * @param User $user Who to give credit for the action
 563          * @return Status
 564          * @since 1.25
 565          */
 566         public static function addTagsAccompanyingChangeWithChecks(
 567                 array $tags, $rc_id, $rev_id, $log_id, $params, User $user
 568         ) {
 569                 // are we allowed to do this?
 570                 $result = self::canAddTagsAccompanyingChange( $tags, $user );
 571                 if ( !$result->isOK() ) {
 572                         $result->value = null;
 573                         return $result;
 574                 }
 575
 576                 // do it!
 577                 self::addTags( $tags, $rc_id, $rev_id, $log_id, $params );
 578
 579                 return Status::newGood( true );
 580         }
 581
 582         /**
 583          * Is it OK to allow the user to adds and remove the given tags tags to/from a
 584          * change?
 585          *
 586          * Extensions should not use this function, unless directly handling a user
 587          * request to add or remove tags from an existing revision or log entry.
 588          *
 589          * @param array $tagsToAdd Tags that you are interested in adding
 590          * @param array $tagsToRemove Tags that you are interested in removing
 591          * @param User|null $user User whose permission you wish to check, or null to
 592          * check for a generic non-blocked user with the relevant rights
 593          * @return Status
 594          * @since 1.25
 595          */
 596         public static function canUpdateTags( array $tagsToAdd, array $tagsToRemove,
 597                 User $user = null
 598         ) {
 599                 if ( !is_null( $user ) ) {
 600                         if ( !MediaWikiServices::getInstance()->getPermissionManager()
 601                                         ->userHasRight( $user, 'changetags' )
 602                         ) {
 603                                 return Status::newFatal( 'tags-update-no-permission' );
 604                         } elseif ( $user->getBlock() ) {
 605                                 // @TODO Ensure that the block does not apply to the `changetags`
 606                                 //       right.
 607                                 return Status::newFatal( 'tags-update-blocked', $user->getName() );
 608                         }
 609                 }
 610
 611                 if ( $tagsToAdd ) {
 612                         // to be added, a tag has to be explicitly defined
 613                         // @todo Allow extensions to define tags that can be applied by users...
 614                         $explicitlyDefinedTags = self::listExplicitlyDefinedTags();
 615                         $diff = array_diff( $tagsToAdd, $explicitlyDefinedTags );
 616                         if ( $diff ) {
 617                                 return self::restrictedTagError( 'tags-update-add-not-allowed-one',
 618                                         'tags-update-add-not-allowed-multi', $diff );
 619                         }
 620                 }
 621
 622                 if ( $tagsToRemove ) {
 623                         // to be removed, a tag must not be defined by an extension, or equivalently it
 624                         // has to be either explicitly defined or not defined at all
 625                         // (assuming no edge case of a tag both explicitly-defined and extension-defined)
 626                         $softwareDefinedTags = self::listSoftwareDefinedTags();
 627                         $intersect = array_intersect( $tagsToRemove, $softwareDefinedTags );
 628                         if ( $intersect ) {
 629                                 return self::restrictedTagError( 'tags-update-remove-not-allowed-one',
 630                                         'tags-update-remove-not-allowed-multi', $intersect );
 631                         }
 632                 }
 633
 634                 return Status::newGood();
 635         }
 636
 637         /**
 638          * Adds and/or removes tags to/from a given change, checking whether it is
 639          * allowed first, and adding a log entry afterwards.
 640          *
 641          * Includes a call to ChangeTags::canUpdateTags(), so your code doesn't need
 642          * to do that. However, it doesn't check whether the *_id parameters are a
 643          * valid combination. That is up to you to enforce. See ApiTag::execute() for
 644          * an example.
 645          *
 646          * Extensions should generally avoid this function. Call
 647          * ChangeTags::updateTags() instead, unless directly handling a user request
 648          * to add or remove tags from an existing revision or log entry.
 649          *
 650          * @param array|null $tagsToAdd If none, pass [] or null
 651          * @param array|null $tagsToRemove If none, pass [] or null
 652          * @param int|null $rc_id The rc_id of the change to add the tags to
 653          * @param int|null $rev_id The rev_id of the change to add the tags to
 654          * @param int|null $log_id The log_id of the change to add the tags to
 655          * @param string|null $params Params to put in the ct_params field of table
 656          * 'change_tag' when adding tags
 657          * @param string $reason Comment for the log
 658          * @param User $user Who to give credit for the action
 659          * @return Status If successful, the value of this Status object will be an
 660          * object (stdClass) with the following fields:
 661          *  - logId: the ID of the added log entry, or null if no log entry was added
 662          *    (i.e. no operation was performed)
 663          *  - addedTags: an array containing the tags that were actually added
 664          *  - removedTags: an array containing the tags that were actually removed
 665          * @since 1.25
 666          */
 667         public static function updateTagsWithChecks( $tagsToAdd, $tagsToRemove,
 668                 $rc_id, $rev_id, $log_id, $params, $reason, User $user
 669         ) {
 670                 if ( is_null( $tagsToAdd ) ) {
 671                         $tagsToAdd = [];
 672                 }
 673                 if ( is_null( $tagsToRemove ) ) {
 674                         $tagsToRemove = [];
 675                 }
 676                 if ( !$tagsToAdd && !$tagsToRemove ) {
 677                         // no-op, don't bother
 678                         return Status::newGood( (object)[
 679                                 'logId' => null,
 680                                 'addedTags' => [],
 681                                 'removedTags' => [],
 682                         ] );
 683                 }
 684
 685                 // are we allowed to do this?
 686                 $result = self::canUpdateTags( $tagsToAdd, $tagsToRemove, $user );
 687                 if ( !$result->isOK() ) {
 688                         $result->value = null;
 689                         return $result;
 690                 }
 691
 692                 // basic rate limiting
 693                 if ( $user->pingLimiter( 'changetag' ) ) {
 694                         return Status::newFatal( 'actionthrottledtext' );
 695                 }
 696
 697                 // do it!
 698                 list( $tagsAdded, $tagsRemoved, $initialTags ) = self::updateTags( $tagsToAdd,
 699                         $tagsToRemove, $rc_id, $rev_id, $log_id, $params, null, $user );
 700                 if ( !$tagsAdded && !$tagsRemoved ) {
 701                         // no-op, don't log it
 702                         return Status::newGood( (object)[
 703                                 'logId' => null,
 704                                 'addedTags' => [],
 705                                 'removedTags' => [],
 706                         ] );
 707                 }
 708
 709                 // log it
 710                 $logEntry = new ManualLogEntry( 'tag', 'update' );
 711                 $logEntry->setPerformer( $user );
 712                 $logEntry->setComment( $reason );
 713
 714                 // find the appropriate target page
 715                 if ( $rev_id ) {
 716                         $rev = Revision::newFromId( $rev_id );
 717                         if ( $rev ) {
 718                                 $logEntry->setTarget( $rev->getTitle() );
 719                         }
 720                 } elseif ( $log_id ) {
 721                         // This function is from revision deletion logic and has nothing to do with
 722                         // change tags, but it appears to be the only other place in core where we
 723                         // perform logged actions on log items.
 724                         $logEntry->setTarget( RevDelLogList::suggestTarget( null, [ $log_id ] ) );
 725                 }
 726
 727                 if ( !$logEntry->getTarget() ) {
 728                         // target is required, so we have to set something
 729                         $logEntry->setTarget( SpecialPage::getTitleFor( 'Tags' ) );
 730                 }
 731
 732                 $logParams = [
 733                         '4::revid' => $rev_id,
 734                         '5::logid' => $log_id,
 735                         '6:list:tagsAdded' => $tagsAdded,
 736                         '7:number:tagsAddedCount' => count( $tagsAdded ),
 737                         '8:list:tagsRemoved' => $tagsRemoved,
 738                         '9:number:tagsRemovedCount' => count( $tagsRemoved ),
 739                         'initialTags' => $initialTags,
 740                 ];
 741                 $logEntry->setParameters( $logParams );
 742                 $logEntry->setRelations( [ 'Tag' => array_merge( $tagsAdded, $tagsRemoved ) ] );
 743
 744                 $dbw = wfGetDB( DB_MASTER );
 745                 $logId = $logEntry->insert( $dbw );
 746                 // Only send this to UDP, not RC, similar to patrol events
 747                 $logEntry->publish( $logId, 'udp' );
 748
 749                 return Status::newGood( (object)[
 750                         'logId' => $logId,
 751                         'addedTags' => $tagsAdded,
 752                         'removedTags' => $tagsRemoved,
 753                 ] );
 754         }
 755
 756         /**
 757          * Applies all tags-related changes to a query.
 758          * Handles selecting tags, and filtering.
 759          * Needs $tables to be set up properly, so we can figure out which join conditions to use.
 760          *
 761          * WARNING: If $filter_tag contains more than one tag, this function will add DISTINCT,
 762          * which may cause performance problems for your query unless you put the ID field of your
 763          * table at the end of the ORDER BY, and set a GROUP BY equal to the ORDER BY. For example,
 764          * if you had ORDER BY foo_timestamp DESC, you will now need GROUP BY foo_timestamp, foo_id
 765          * ORDER BY foo_timestamp DESC, foo_id DESC.
 766          *
 767          * @param string|array &$tables Table names, see Database::select
 768          * @param string|array &$fields Fields used in query, see Database::select
 769          * @param string|array &$conds Conditions used in query, see Database::select
 770          * @param array &$join_conds Join conditions, see Database::select
 771          * @param string|array &$options Options, see Database::select
 772          * @param string|array $filter_tag Tag(s) to select on
 773          *
 774          * @throws MWException When unable to determine appropriate JOIN condition for tagging
 775          */
 776         public static function modifyDisplayQuery( &$tables, &$fields, &$conds,
 777                 &$join_conds, &$options, $filter_tag = ''
 778         ) {
 779                 global $wgUseTagFilter;
 780
 781                 // Normalize to arrays
 782                 $tables = (array)$tables;
 783                 $fields = (array)$fields;
 784                 $conds = (array)$conds;
 785                 $options = (array)$options;
 786
 787                 $fields['ts_tags'] = self::makeTagSummarySubquery( $tables );
 788
 789                 // Figure out which ID field to use
 790                 if ( in_array( 'recentchanges', $tables ) ) {
 791                         $join_cond = 'ct_rc_id=rc_id';
 792                 } elseif ( in_array( 'logging', $tables ) ) {
 793                         $join_cond = 'ct_log_id=log_id';
 794                 } elseif ( in_array( 'revision', $tables ) ) {
 795                         $join_cond = 'ct_rev_id=rev_id';
 796                 } elseif ( in_array( 'archive', $tables ) ) {
 797                         $join_cond = 'ct_rev_id=ar_rev_id';
 798                 } else {
 799                         throw new MWException( 'Unable to determine appropriate JOIN condition for tagging.' );
 800                 }
 801
 802                 if ( $wgUseTagFilter && $filter_tag ) {
 803                         // Somebody wants to filter on a tag.
 804                         // Add an INNER JOIN on change_tag
 805
 806                         $tables[] = 'change_tag';
 807                         $join_conds['change_tag'] = [ 'JOIN', $join_cond ];
 808                         $filterTagIds = [];
 809                         $changeTagDefStore = MediaWikiServices::getInstance()->getChangeTagDefStore();
 810                         foreach ( (array)$filter_tag as $filterTagName ) {
 811                                 try {
 812                                         $filterTagIds[] = $changeTagDefStore->getId( $filterTagName );
 813                                 } catch ( NameTableAccessException $exception ) {
 814                                         // Return nothing.
 815                                         $conds[] = '0';
 816                                         break;
 817                                 }
 818                         }
 819
 820                         if ( $filterTagIds !== [] ) {
 821                                 $conds['ct_tag_id'] = $filterTagIds;
 822                         }
 823
 824                         if (
 825                                 is_array( $filter_tag ) && count( $filter_tag ) > 1 &&
 826                                 !in_array( 'DISTINCT', $options )
 827                         ) {
 828                                 $options[] = 'DISTINCT';
 829                         }
 830                 }
 831         }
 832
 833         /**
 834          * Make the tag summary subquery based on the given tables and return it.
 835          *
 836          * @param string|array $tables Table names, see Database::select
 837          *
 838          * @return string tag summary subqeury
 839          * @throws MWException When unable to determine appropriate JOIN condition for tagging
 840          */
 841         public static function makeTagSummarySubquery( $tables ) {
 842                 // Normalize to arrays
 843                 $tables = (array)$tables;
 844
 845                 // Figure out which ID field to use
 846                 if ( in_array( 'recentchanges', $tables ) ) {
 847                         $join_cond = 'ct_rc_id=rc_id';
 848                 } elseif ( in_array( 'logging', $tables ) ) {
 849                         $join_cond = 'ct_log_id=log_id';
 850                 } elseif ( in_array( 'revision', $tables ) ) {
 851                         $join_cond = 'ct_rev_id=rev_id';
 852                 } elseif ( in_array( 'archive', $tables ) ) {
 853                         $join_cond = 'ct_rev_id=ar_rev_id';
 854                 } else {
 855                         throw new MWException( 'Unable to determine appropriate JOIN condition for tagging.' );
 856                 }
 857
 858                 $tagTables = [ 'change_tag', 'change_tag_def' ];
 859                 $join_cond_ts_tags = [ 'change_tag_def' => [ 'JOIN', 'ct_tag_id=ctd_id' ] ];
 860                 $field = 'ctd_name';
 861
 862                 return wfGetDB( DB_REPLICA )->buildGroupConcatField(
 863                         ',', $tagTables, $field, $join_cond, $join_cond_ts_tags
 864                 );
 865         }
 866
 867         /**
 868          * Build a text box to select a change tag
 869          *
 870          * @param string $selected Tag to select by default
 871          * @param bool $ooui Use an OOUI TextInputWidget as selector instead of a non-OOUI input field
 872          *        You need to call OutputPage::enableOOUI() yourself.
 873          * @param IContextSource|null $context
 874          * @note Even though it takes null as a valid argument, an IContextSource is preferred
 875          *       in a new code, as the null value can change in the future
 876          * @return array an array of (label, selector)
 877          */
 878         public static function buildTagFilterSelector(
 879                 $selected = '', $ooui = false, IContextSource $context = null
 880         ) {
 881                 if ( !$context ) {
 882                         $context = RequestContext::getMain();
 883                 }
 884
 885                 $config = $context->getConfig();
 886                 if ( !$config->get( 'UseTagFilter' ) || !count( self::listDefinedTags() ) ) {
 887                         return [];
 888                 }
 889
 890                 $data = [
 891                         Html::rawElement(
 892                                 'label',
 893                                 [ 'for' => 'tagfilter' ],
 894                                 $context->msg( 'tag-filter' )->parse()
 895                         )
 896                 ];
 897
 898                 if ( $ooui ) {
 899                         $data[] = new OOUI\TextInputWidget( [
 900                                 'id' => 'tagfilter',
 901                                 'name' => 'tagfilter',
 902                                 'value' => $selected,
 903                                 'classes' => 'mw-tagfilter-input',
 904                         ] );
 905                 } else {
 906                         $data[] = Xml::input(
 907                                 'tagfilter',
 908                                 20,
 909                                 $selected,
 910                                 [ 'class' => 'mw-tagfilter-input mw-ui-input mw-ui-input-inline', 'id' => 'tagfilter' ]
 911                         );
 912                 }
 913
 914                 return $data;
 915         }
 916
 917         /**
 918          * Set ctd_user_defined = 1 in change_tag_def without checking that the tag name is valid.
 919          * Extensions should NOT use this function; they can use the ListDefinedTags
 920          * hook instead.
 921          *
 922          * @param string $tag Tag to create
 923          * @since 1.25
 924          */
 925         public static function defineTag( $tag ) {
 926                 $dbw = wfGetDB( DB_MASTER );
 927                 $tagDef = [
 928                         'ctd_name' => $tag,
 929                         'ctd_user_defined' => 1,
 930                         'ctd_count' => 0
 931                 ];
 932                 $dbw->upsert(
 933                         'change_tag_def',
 934                         $tagDef,
 935                         [ 'ctd_name' ],
 936                         [ 'ctd_user_defined' => 1 ],
 937                         __METHOD__
 938                 );
 939
 940                 // clear the memcache of defined tags
 941                 self::purgeTagCacheAll();
 942         }
 943
 944         /**
 945          * Update ctd_user_defined = 0 field in change_tag_def.
 946          * The tag may remain in use by extensions, and may still show up as 'defined'
 947          * if an extension is setting it from the ListDefinedTags hook.
 948          *
 949          * @param string $tag Tag to remove
 950          * @since 1.25
 951          */
 952         public static function undefineTag( $tag ) {
 953                 $dbw = wfGetDB( DB_MASTER );
 954
 955                 $dbw->update(
 956                         'change_tag_def',
 957                         [ 'ctd_user_defined' => 0 ],
 958                         [ 'ctd_name' => $tag ],
 959                         __METHOD__
 960                 );
 961
 962                 $dbw->delete(
 963                         'change_tag_def',
 964                         [ 'ctd_name' => $tag, 'ctd_count' => 0 ],
 965                         __METHOD__
 966                 );
 967
 968                 // clear the memcache of defined tags
 969                 self::purgeTagCacheAll();
 970         }
 971
 972         /**
 973          * Writes a tag action into the tag management log.
 974          *
 975          * @param string $action
 976          * @param string $tag
 977          * @param string $reason
 978          * @param User $user Who to attribute the action to
 979          * @param int|null $tagCount For deletion only, how many usages the tag had before
 980          * it was deleted.
 981          * @param array $logEntryTags Change tags to apply to the entry
 982          * that will be created in the tag management log
 983          * @return int ID of the inserted log entry
 984          * @since 1.25
 985          */
 986         protected static function logTagManagementAction( $action, $tag, $reason,
 987                 User $user, $tagCount = null, array $logEntryTags = []
 988         ) {
 989                 $dbw = wfGetDB( DB_MASTER );
 990
 991                 $logEntry = new ManualLogEntry( 'managetags', $action );
 992                 $logEntry->setPerformer( $user );
 993                 // target page is not relevant, but it has to be set, so we just put in
 994                 // the title of Special:Tags
 995                 $logEntry->setTarget( Title::newFromText( 'Special:Tags' ) );
 996                 $logEntry->setComment( $reason );
 997
 998                 $params = [ '4::tag' => $tag ];
 999                 if ( !is_null( $tagCount ) ) {
1000                         $params['5:number:count'] = $tagCount;
1001                 }
1002                 $logEntry->setParameters( $params );
1003                 $logEntry->setRelations( [ 'Tag' => $tag ] );
1004                 $logEntry->addTags( $logEntryTags );
1005
1006                 $logId = $logEntry->insert( $dbw );
1007                 $logEntry->publish( $logId );
1008                 return $logId;
1009         }
1010
1011         /**
1012          * Is it OK to allow the user to activate this tag?
1013          *
1014          * @param string $tag Tag that you are interested in activating
1015          * @param User|null $user User whose permission you wish to check, or null if
1016          * you don't care (e.g. maintenance scripts)
1017          * @return Status
1018          * @since 1.25
1019          */
1020         public static function canActivateTag( $tag, User $user = null ) {
1021                 if ( !is_null( $user ) ) {
1022                         if ( !MediaWikiServices::getInstance()->getPermissionManager()
1023                                         ->userHasRight( $user, 'managechangetags' )
1024                         ) {
1025                                 return Status::newFatal( 'tags-manage-no-permission' );
1026                         } elseif ( $user->getBlock() ) {
1027                                 // @TODO Ensure that the block does not apply to the `managechangetags`
1028                                 //       right.
1029                                 return Status::newFatal( 'tags-manage-blocked', $user->getName() );
1030                         }
1031                 }
1032
1033                 // defined tags cannot be activated (a defined tag is either extension-
1034                 // defined, in which case the extension chooses whether or not to active it;
1035                 // or user-defined, in which case it is considered active)
1036                 $definedTags = self::listDefinedTags();
1037                 if ( in_array( $tag, $definedTags ) ) {
1038                         return Status::newFatal( 'tags-activate-not-allowed', $tag );
1039                 }
1040
1041                 // non-existing tags cannot be activated
1042                 $tagUsage = self::tagUsageStatistics();
1043                 if ( !isset( $tagUsage[$tag] ) ) { // we already know the tag is undefined
1044                         return Status::newFatal( 'tags-activate-not-found', $tag );
1045                 }
1046
1047                 return Status::newGood();
1048         }
1049
1050         /**
1051          * Activates a tag, checking whether it is allowed first, and adding a log
1052          * entry afterwards.
1053          *
1054          * Includes a call to ChangeTag::canActivateTag(), so your code doesn't need
1055          * to do that.
1056          *
1057          * @param string $tag
1058          * @param string $reason
1059          * @param User $user Who to give credit for the action
1060          * @param bool $ignoreWarnings Can be used for API interaction, default false
1061          * @param array $logEntryTags Change tags to apply to the entry
1062          * that will be created in the tag management log
1063          * @return Status If successful, the Status contains the ID of the added log
1064          * entry as its value
1065          * @since 1.25
1066          */
1067         public static function activateTagWithChecks( $tag, $reason, User $user,
1068                 $ignoreWarnings = false, array $logEntryTags = []
1069         ) {
1070                 // are we allowed to do this?
1071                 $result = self::canActivateTag( $tag, $user );
1072                 if ( $ignoreWarnings ? !$result->isOK() : !$result->isGood() ) {
1073                         $result->value = null;
1074                         return $result;
1075                 }
1076
1077                 // do it!
1078                 self::defineTag( $tag );
1079
1080                 // log it
1081                 $logId = self::logTagManagementAction( 'activate', $tag, $reason, $user,
1082                         null, $logEntryTags );
1083
1084                 return Status::newGood( $logId );
1085         }
1086
1087         /**
1088          * Is it OK to allow the user to deactivate this tag?
1089          *
1090          * @param string $tag Tag that you are interested in deactivating
1091          * @param User|null $user User whose permission you wish to check, or null if
1092          * you don't care (e.g. maintenance scripts)
1093          * @return Status
1094          * @since 1.25
1095          */
1096         public static function canDeactivateTag( $tag, User $user = null ) {
1097                 if ( !is_null( $user ) ) {
1098                         if ( !MediaWikiServices::getInstance()->getPermissionManager()
1099                                         ->userHasRight( $user, 'managechangetags' )
1100                         ) {
1101                                 return Status::newFatal( 'tags-manage-no-permission' );
1102                         } elseif ( $user->getBlock() ) {
1103                                 // @TODO Ensure that the block does not apply to the `managechangetags`
1104                                 //       right.
1105                                 return Status::newFatal( 'tags-manage-blocked', $user->getName() );
1106                         }
1107                 }
1108
1109                 // only explicitly-defined tags can be deactivated
1110                 $explicitlyDefinedTags = self::listExplicitlyDefinedTags();
1111                 if ( !in_array( $tag, $explicitlyDefinedTags ) ) {
1112                         return Status::newFatal( 'tags-deactivate-not-allowed', $tag );
1113                 }
1114                 return Status::newGood();
1115         }
1116
1117         /**
1118          * Deactivates a tag, checking whether it is allowed first, and adding a log
1119          * entry afterwards.
1120          *
1121          * Includes a call to ChangeTag::canDeactivateTag(), so your code doesn't need
1122          * to do that.
1123          *
1124          * @param string $tag
1125          * @param string $reason
1126          * @param User $user Who to give credit for the action
1127          * @param bool $ignoreWarnings Can be used for API interaction, default false
1128          * @param array $logEntryTags Change tags to apply to the entry
1129          * that will be created in the tag management log
1130          * @return Status If successful, the Status contains the ID of the added log
1131          * entry as its value
1132          * @since 1.25
1133          */
1134         public static function deactivateTagWithChecks( $tag, $reason, User $user,
1135                 $ignoreWarnings = false, array $logEntryTags = []
1136         ) {
1137                 // are we allowed to do this?
1138                 $result = self::canDeactivateTag( $tag, $user );
1139                 if ( $ignoreWarnings ? !$result->isOK() : !$result->isGood() ) {
1140                         $result->value = null;
1141                         return $result;
1142                 }
1143
1144                 // do it!
1145                 self::undefineTag( $tag );
1146
1147                 // log it
1148                 $logId = self::logTagManagementAction( 'deactivate', $tag, $reason, $user,
1149                         null, $logEntryTags );
1150
1151                 return Status::newGood( $logId );
1152         }
1153
1154         /**
1155          * Is the tag name valid?
1156          *
1157          * @param string $tag Tag that you are interested in creating
1158          * @return Status
1159          * @since 1.30
1160          */
1161         public static function isTagNameValid( $tag ) {
1162                 // no empty tags
1163                 if ( $tag === '' ) {
1164                         return Status::newFatal( 'tags-create-no-name' );
1165                 }
1166
1167                 // tags cannot contain commas (used to be used as a delimiter in tag_summary table),
1168                 // pipe (used as a delimiter between multiple tags in
1169                 // SpecialRecentchanges and friends), or slashes (would break tag description messages in
1170                 // MediaWiki namespace)
1171                 if ( strpos( $tag, ',' ) !== false || strpos( $tag, '|' ) !== false
1172                         || strpos( $tag, '/' ) !== false ) {
1173                         return Status::newFatal( 'tags-create-invalid-chars' );
1174                 }
1175
1176                 // could the MediaWiki namespace description messages be created?
1177                 $title = Title::makeTitleSafe( NS_MEDIAWIKI, "Tag-$tag-description" );
1178                 if ( is_null( $title ) ) {
1179                         return Status::newFatal( 'tags-create-invalid-title-chars' );
1180                 }
1181
1182                 return Status::newGood();
1183         }
1184
1185         /**
1186          * Is it OK to allow the user to create this tag?
1187          *
1188          * Extensions should NOT use this function. In most cases, a tag can be
1189          * defined using the ListDefinedTags hook without any checking.
1190          *
1191          * @param string $tag Tag that you are interested in creating
1192          * @param User|null $user User whose permission you wish to check, or null if
1193          * you don't care (e.g. maintenance scripts)
1194          * @return Status
1195          * @since 1.25
1196          */
1197         public static function canCreateTag( $tag, User $user = null ) {
1198                 if ( !is_null( $user ) ) {
1199                         if ( !MediaWikiServices::getInstance()->getPermissionManager()
1200                                         ->userHasRight( $user, 'managechangetags' )
1201                         ) {
1202                                 return Status::newFatal( 'tags-manage-no-permission' );
1203                         } elseif ( $user->getBlock() ) {
1204                                 // @TODO Ensure that the block does not apply to the `managechangetags`
1205                                 //       right.
1206                                 return Status::newFatal( 'tags-manage-blocked', $user->getName() );
1207                         }
1208                 }
1209
1210                 $status = self::isTagNameValid( $tag );
1211                 if ( !$status->isGood() ) {
1212                         return $status;
1213                 }
1214
1215                 // does the tag already exist?
1216                 $tagUsage = self::tagUsageStatistics();
1217                 if ( isset( $tagUsage[$tag] ) || in_array( $tag, self::listDefinedTags() ) ) {
1218                         return Status::newFatal( 'tags-create-already-exists', $tag );
1219                 }
1220
1221                 // check with hooks
1222                 $canCreateResult = Status::newGood();
1223                 Hooks::run( 'ChangeTagCanCreate', [ $tag, $user, &$canCreateResult ] );
1224                 return $canCreateResult;
1225         }
1226
1227         /**
1228          * Creates a tag by adding it to `change_tag_def` table.
1229          *
1230          * Extensions should NOT use this function; they can use the ListDefinedTags
1231          * hook instead.
1232          *
1233          * Includes a call to ChangeTag::canCreateTag(), so your code doesn't need to
1234          * do that.
1235          *
1236          * @param string $tag
1237          * @param string $reason
1238          * @param User $user Who to give credit for the action
1239          * @param bool $ignoreWarnings Can be used for API interaction, default false
1240          * @param array $logEntryTags Change tags to apply to the entry
1241          * that will be created in the tag management log
1242          * @return Status If successful, the Status contains the ID of the added log
1243          * entry as its value
1244          * @since 1.25
1245          */
1246         public static function createTagWithChecks( $tag, $reason, User $user,
1247                 $ignoreWarnings = false, array $logEntryTags = []
1248         ) {
1249                 // are we allowed to do this?
1250                 $result = self::canCreateTag( $tag, $user );
1251                 if ( $ignoreWarnings ? !$result->isOK() : !$result->isGood() ) {
1252                         $result->value = null;
1253                         return $result;
1254                 }
1255
1256                 // do it!
1257                 self::defineTag( $tag );
1258
1259                 // log it
1260                 $logId = self::logTagManagementAction( 'create', $tag, $reason, $user,
1261                         null, $logEntryTags );
1262
1263                 return Status::newGood( $logId );
1264         }
1265
1266         /**
1267          * Permanently removes all traces of a tag from the DB. Good for removing
1268          * misspelt or temporary tags.
1269          *
1270          * This function should be directly called by maintenance scripts only, never
1271          * by user-facing code. See deleteTagWithChecks() for functionality that can
1272          * safely be exposed to users.
1273          *
1274          * @param string $tag Tag to remove
1275          * @return Status The returned status will be good unless a hook changed it
1276          * @since 1.25
1277          */
1278         public static function deleteTagEverywhere( $tag ) {
1279                 $dbw = wfGetDB( DB_MASTER );
1280                 $dbw->startAtomic( __METHOD__ );
1281
1282                 // fetch tag id, this must be done before calling undefineTag(), see T225564
1283                 $tagId = MediaWikiServices::getInstance()->getChangeTagDefStore()->getId( $tag );
1284
1285                 // set ctd_user_defined = 0
1286                 self::undefineTag( $tag );
1287
1288                 // delete from change_tag
1289                 $dbw->delete( 'change_tag', [ 'ct_tag_id' => $tagId ], __METHOD__ );
1290                 $dbw->delete( 'change_tag_def', [ 'ctd_name' => $tag ], __METHOD__ );
1291                 $dbw->endAtomic( __METHOD__ );
1292
1293                 // give extensions a chance
1294                 $status = Status::newGood();
1295                 Hooks::run( 'ChangeTagAfterDelete', [ $tag, &$status ] );
1296                 // let's not allow error results, as the actual tag deletion succeeded
1297                 if ( !$status->isOK() ) {
1298                         wfDebug( 'ChangeTagAfterDelete error condition downgraded to warning' );
1299                         $status->setOK( true );
1300                 }
1301
1302                 // clear the memcache of defined tags
1303                 self::purgeTagCacheAll();
1304
1305                 return $status;
1306         }
1307
1308         /**
1309          * Is it OK to allow the user to delete this tag?
1310          *
1311          * @param string $tag Tag that you are interested in deleting
1312          * @param User|null $user User whose permission you wish to check, or null if
1313          * you don't care (e.g. maintenance scripts)
1314          * @return Status
1315          * @since 1.25
1316          */
1317         public static function canDeleteTag( $tag, User $user = null ) {
1318                 $tagUsage = self::tagUsageStatistics();
1319
1320                 if ( !is_null( $user ) ) {
1321                         if ( !MediaWikiServices::getInstance()->getPermissionManager()
1322                                         ->userHasRight( $user, 'deletechangetags' )
1323                         ) {
1324                                 return Status::newFatal( 'tags-delete-no-permission' );
1325                         } elseif ( $user->getBlock() ) {
1326                                 // @TODO Ensure that the block does not apply to the `deletechangetags`
1327                                 //       right.
1328                                 return Status::newFatal( 'tags-manage-blocked', $user->getName() );
1329                         }
1330                 }
1331
1332                 if ( !isset( $tagUsage[$tag] ) && !in_array( $tag, self::listDefinedTags() ) ) {
1333                         return Status::newFatal( 'tags-delete-not-found', $tag );
1334                 }
1335
1336                 if ( isset( $tagUsage[$tag] ) && $tagUsage[$tag] > self::MAX_DELETE_USES ) {
1337                         return Status::newFatal( 'tags-delete-too-many-uses', $tag, self::MAX_DELETE_USES );
1338                 }
1339
1340                 $softwareDefined = self::listSoftwareDefinedTags();
1341                 if ( in_array( $tag, $softwareDefined ) ) {
1342                         // extension-defined tags can't be deleted unless the extension
1343                         // specifically allows it
1344                         $status = Status::newFatal( 'tags-delete-not-allowed' );
1345                 } else {
1346                         // user-defined tags are deletable unless otherwise specified
1347                         $status = Status::newGood();
1348                 }
1349
1350                 Hooks::run( 'ChangeTagCanDelete', [ $tag, $user, &$status ] );
1351                 return $status;
1352         }
1353
1354         /**
1355          * Deletes a tag, checking whether it is allowed first, and adding a log entry
1356          * afterwards.
1357          *
1358          * Includes a call to ChangeTag::canDeleteTag(), so your code doesn't need to
1359          * do that.
1360          *
1361          * @param string $tag
1362          * @param string $reason
1363          * @param User $user Who to give credit for the action
1364          * @param bool $ignoreWarnings Can be used for API interaction, default false
1365          * @param array $logEntryTags Change tags to apply to the entry
1366          * that will be created in the tag management log
1367          * @return Status If successful, the Status contains the ID of the added log
1368          * entry as its value
1369          * @since 1.25
1370          */
1371         public static function deleteTagWithChecks( $tag, $reason, User $user,
1372                 $ignoreWarnings = false, array $logEntryTags = []
1373         ) {
1374                 // are we allowed to do this?
1375                 $result = self::canDeleteTag( $tag, $user );
1376                 if ( $ignoreWarnings ? !$result->isOK() : !$result->isGood() ) {
1377                         $result->value = null;
1378                         return $result;
1379                 }
1380
1381                 // store the tag usage statistics
1382                 $tagUsage = self::tagUsageStatistics();
1383                 $hitcount = $tagUsage[$tag] ?? 0;
1384
1385                 // do it!
1386                 $deleteResult = self::deleteTagEverywhere( $tag );
1387                 if ( !$deleteResult->isOK() ) {
1388                         return $deleteResult;
1389                 }
1390
1391                 // log it
1392                 $logId = self::logTagManagementAction( 'delete', $tag, $reason, $user,
1393                         $hitcount, $logEntryTags );
1394
1395                 $deleteResult->value = $logId;
1396                 return $deleteResult;
1397         }
1398
1399         /**
1400          * Lists those tags which core or extensions report as being "active".
1401          *
1402          * @return array
1403          * @since 1.25
1404          */
1405         public static function listSoftwareActivatedTags() {
1406                 // core active tags
1407                 $tags = self::getSoftwareTags();
1408                 if ( !Hooks::isRegistered( 'ChangeTagsListActive' ) ) {
1409                         return $tags;
1410                 }
1411                 $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
1412                 return $cache->getWithSetCallback(
1413                         $cache->makeKey( 'active-tags' ),
1414                         WANObjectCache::TTL_MINUTE * 5,
1415                         function ( $oldValue, &$ttl, array &$setOpts ) use ( $tags ) {
1416                                 $setOpts += Database::getCacheSetOptions( wfGetDB( DB_REPLICA ) );
1417
1418                                 // Ask extensions which tags they consider active
1419                                 Hooks::run( 'ChangeTagsListActive', [ &$tags ] );
1420                                 return $tags;
1421                         },
1422                         [
1423                                 'checkKeys' => [ $cache->makeKey( 'active-tags' ) ],
1424                                 'lockTSE' => WANObjectCache::TTL_MINUTE * 5,
1425                                 'pcTTL' => WANObjectCache::TTL_PROC_LONG
1426                         ]
1427                 );
1428         }
1429
1430         /**
1431          * Basically lists defined tags which count even if they aren't applied to anything.
1432          * It returns a union of the results of listExplicitlyDefinedTags()
1433          *
1434          * @return string[] Array of strings: tags
1435          */
1436         public static function listDefinedTags() {
1437                 $tags1 = self::listExplicitlyDefinedTags();
1438                 $tags2 = self::listSoftwareDefinedTags();
1439                 return array_values( array_unique( array_merge( $tags1, $tags2 ) ) );
1440         }
1441
1442         /**
1443          * Lists tags explicitly defined in the `change_tag_def` table of the database.
1444          *
1445          * Tries memcached first.
1446          *
1447          * @return string[] Array of strings: tags
1448          * @since 1.25
1449          */
1450         public static function listExplicitlyDefinedTags() {
1451                 $fname = __METHOD__;
1452
1453                 $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
1454                 return $cache->getWithSetCallback(
1455                         $cache->makeKey( 'valid-tags-db' ),
1456                         WANObjectCache::TTL_MINUTE * 5,
1457                         function ( $oldValue, &$ttl, array &$setOpts ) use ( $fname ) {
1458                                 $dbr = wfGetDB( DB_REPLICA );
1459
1460                                 $setOpts += Database::getCacheSetOptions( $dbr );
1461
1462                                 $tags = $dbr->selectFieldValues(
1463                                         'change_tag_def',
1464                                         'ctd_name',
1465                                         [ 'ctd_user_defined' => 1 ],
1466                                         $fname
1467                                 );
1468
1469                                 return array_filter( array_unique( $tags ) );
1470                         },
1471                         [
1472                                 'checkKeys' => [ $cache->makeKey( 'valid-tags-db' ) ],
1473                                 'lockTSE' => WANObjectCache::TTL_MINUTE * 5,
1474                                 'pcTTL' => WANObjectCache::TTL_PROC_LONG
1475                         ]
1476                 );
1477         }
1478
1479         /**
1480          * Lists tags defined by core or extensions using the ListDefinedTags hook.
1481          * Extensions need only define those tags they deem to be in active use.
1482          *
1483          * Tries memcached first.
1484          *
1485          * @return string[] Array of strings: tags
1486          * @since 1.25
1487          */
1488         public static function listSoftwareDefinedTags() {
1489                 // core defined tags
1490                 $tags = self::getSoftwareTags( true );
1491                 if ( !Hooks::isRegistered( 'ListDefinedTags' ) ) {
1492                         return $tags;
1493                 }
1494                 $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
1495                 return $cache->getWithSetCallback(
1496                         $cache->makeKey( 'valid-tags-hook' ),
1497                         WANObjectCache::TTL_MINUTE * 5,
1498                         function ( $oldValue, &$ttl, array &$setOpts ) use ( $tags ) {
1499                                 $setOpts += Database::getCacheSetOptions( wfGetDB( DB_REPLICA ) );
1500
1501                                 Hooks::run( 'ListDefinedTags', [ &$tags ] );
1502                                 return array_filter( array_unique( $tags ) );
1503                         },
1504                         [
1505                                 'checkKeys' => [ $cache->makeKey( 'valid-tags-hook' ) ],
1506                                 'lockTSE' => WANObjectCache::TTL_MINUTE * 5,
1507                                 'pcTTL' => WANObjectCache::TTL_PROC_LONG
1508                         ]
1509                 );
1510         }
1511
1512         /**
1513          * Invalidates the short-term cache of defined tags used by the
1514          * list*DefinedTags functions, as well as the tag statistics cache.
1515          * @since 1.25
1516          */
1517         public static function purgeTagCacheAll() {
1518                 $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
1519
1520                 $cache->touchCheckKey( $cache->makeKey( 'active-tags' ) );
1521                 $cache->touchCheckKey( $cache->makeKey( 'valid-tags-db' ) );
1522                 $cache->touchCheckKey( $cache->makeKey( 'valid-tags-hook' ) );
1523                 $cache->touchCheckKey( $cache->makeKey( 'tags-usage-statistics' ) );
1524
1525                 MediaWikiServices::getInstance()->getChangeTagDefStore()->reloadMap();
1526         }
1527
1528         /**
1529          * Returns a map of any tags used on the wiki to number of edits
1530          * tagged with them, ordered descending by the hitcount.
1531          * This does not include tags defined somewhere that have never been applied.
1532          * @return array Array of string => int
1533          */
1534         public static function tagUsageStatistics() {
1535                 $fname = __METHOD__;
1536
1537                 $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
1538                 return $cache->getWithSetCallback(
1539                         $cache->makeKey( 'tags-usage-statistics' ),
1540                         WANObjectCache::TTL_MINUTE * 5,
1541                         function ( $oldValue, &$ttl, array &$setOpts ) use ( $fname ) {
1542                                 $dbr = wfGetDB( DB_REPLICA );
1543                                 $res = $dbr->select(
1544                                         'change_tag_def',
1545                                         [ 'ctd_name', 'ctd_count' ],
1546                                         [],
1547                                         $fname,
1548                                         [ 'ORDER BY' => 'ctd_count DESC' ]
1549                                 );
1550
1551                                 $out = [];
1552                                 foreach ( $res as $row ) {
1553                                         $out[$row->ctd_name] = $row->ctd_count;
1554                                 }
1555
1556                                 return $out;
1557                         },
1558                         [
1559                                 'checkKeys' => [ $cache->makeKey( 'tags-usage-statistics' ) ],
1560                                 'lockTSE' => WANObjectCache::TTL_MINUTE * 5,
1561                                 'pcTTL' => WANObjectCache::TTL_PROC_LONG
1562                         ]
1563                 );
1564         }
1565
1566         /**
1567          * Indicate whether change tag editing UI is relevant
1568          *
1569          * Returns true if the user has the necessary right and there are any
1570          * editable tags defined.
1571          *
1572          * This intentionally doesn't check "any addable || any deletable", because
1573          * it seems like it would be more confusing than useful if the checkboxes
1574          * suddenly showed up because some abuse filter stopped defining a tag and
1575          * then suddenly disappeared when someone deleted all uses of that tag.
1576          *
1577          * @param User $user
1578          * @return bool
1579          */
1580         public static function showTagEditingUI( User $user ) {
1581                 return MediaWikiServices::getInstance()->getPermissionManager()
1582                                    ->userHasRight( $user, 'changetags' ) &&
1583                            (bool)self::listExplicitlyDefinedTags();
1584         }
1585 }