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() && $user->getBlock()->isSitewide() ) {
 528                                 return Status::newFatal( 'tags-apply-blocked', $user->getName() );
 529                         }
 530                 }
 531
 532                 // to be applied, a tag has to be explicitly defined
 533                 $allowedTags = self::listExplicitlyDefinedTags();
 534                 Hooks::run( 'ChangeTagsAllowedAdd', [ &$allowedTags, $tags, $user ] );
 535                 $disallowedTags = array_diff( $tags, $allowedTags );
 536                 if ( $disallowedTags ) {
 537                         return self::restrictedTagError( 'tags-apply-not-allowed-one',
 538                                 'tags-apply-not-allowed-multi', $disallowedTags );
 539                 }
 540
 541                 return Status::newGood();
 542         }
 543
 544         /**
 545          * Adds tags to a given change, checking whether it is allowed first, but
 546          * without adding a log entry. Useful for cases where the tag is being added
 547          * along with the action that generated the change (e.g. tagging an edit as
 548          * it is being made).
 549          *
 550          * Extensions should not use this function, unless directly handling a user
 551          * request to add a particular tag. Normally, extensions should call
 552          * ChangeTags::updateTags() instead.
 553          *
 554          * @param array $tags Tags to apply
 555          * @param int|null $rc_id The rc_id of the change to add the tags to
 556          * @param int|null $rev_id The rev_id of the change to add the tags to
 557          * @param int|null $log_id The log_id of the change to add the tags to
 558          * @param string $params Params to put in the ct_params field of table
 559          * 'change_tag' when adding tags
 560          * @param User $user Who to give credit for the action
 561          * @return Status
 562          * @since 1.25
 563          */
 564         public static function addTagsAccompanyingChangeWithChecks(
 565                 array $tags, $rc_id, $rev_id, $log_id, $params, User $user
 566         ) {
 567                 // are we allowed to do this?
 568                 $result = self::canAddTagsAccompanyingChange( $tags, $user );
 569                 if ( !$result->isOK() ) {
 570                         $result->value = null;
 571                         return $result;
 572                 }
 573
 574                 // do it!
 575                 self::addTags( $tags, $rc_id, $rev_id, $log_id, $params );
 576
 577                 return Status::newGood( true );
 578         }
 579
 580         /**
 581          * Is it OK to allow the user to adds and remove the given tags tags to/from a
 582          * change?
 583          *
 584          * Extensions should not use this function, unless directly handling a user
 585          * request to add or remove tags from an existing revision or log entry.
 586          *
 587          * @param array $tagsToAdd Tags that you are interested in adding
 588          * @param array $tagsToRemove Tags that you are interested in removing
 589          * @param User|null $user User whose permission you wish to check, or null to
 590          * check for a generic non-blocked user with the relevant rights
 591          * @return Status
 592          * @since 1.25
 593          */
 594         public static function canUpdateTags( array $tagsToAdd, array $tagsToRemove,
 595                 User $user = null
 596         ) {
 597                 if ( !is_null( $user ) ) {
 598                         if ( !MediaWikiServices::getInstance()->getPermissionManager()
 599                                         ->userHasRight( $user, 'changetags' )
 600                         ) {
 601                                 return Status::newFatal( 'tags-update-no-permission' );
 602                         } elseif ( $user->getBlock() && $user->getBlock()->isSitewide() ) {
 603                                 return Status::newFatal( 'tags-update-blocked', $user->getName() );
 604                         }
 605                 }
 606
 607                 if ( $tagsToAdd ) {
 608                         // to be added, a tag has to be explicitly defined
 609                         // @todo Allow extensions to define tags that can be applied by users...
 610                         $explicitlyDefinedTags = self::listExplicitlyDefinedTags();
 611                         $diff = array_diff( $tagsToAdd, $explicitlyDefinedTags );
 612                         if ( $diff ) {
 613                                 return self::restrictedTagError( 'tags-update-add-not-allowed-one',
 614                                         'tags-update-add-not-allowed-multi', $diff );
 615                         }
 616                 }
 617
 618                 if ( $tagsToRemove ) {
 619                         // to be removed, a tag must not be defined by an extension, or equivalently it
 620                         // has to be either explicitly defined or not defined at all
 621                         // (assuming no edge case of a tag both explicitly-defined and extension-defined)
 622                         $softwareDefinedTags = self::listSoftwareDefinedTags();
 623                         $intersect = array_intersect( $tagsToRemove, $softwareDefinedTags );
 624                         if ( $intersect ) {
 625                                 return self::restrictedTagError( 'tags-update-remove-not-allowed-one',
 626                                         'tags-update-remove-not-allowed-multi', $intersect );
 627                         }
 628                 }
 629
 630                 return Status::newGood();
 631         }
 632
 633         /**
 634          * Adds and/or removes tags to/from a given change, checking whether it is
 635          * allowed first, and adding a log entry afterwards.
 636          *
 637          * Includes a call to ChangeTags::canUpdateTags(), so your code doesn't need
 638          * to do that. However, it doesn't check whether the *_id parameters are a
 639          * valid combination. That is up to you to enforce. See ApiTag::execute() for
 640          * an example.
 641          *
 642          * Extensions should generally avoid this function. Call
 643          * ChangeTags::updateTags() instead, unless directly handling a user request
 644          * to add or remove tags from an existing revision or log entry.
 645          *
 646          * @param array|null $tagsToAdd If none, pass [] or null
 647          * @param array|null $tagsToRemove If none, pass [] or null
 648          * @param int|null $rc_id The rc_id of the change to add the tags to
 649          * @param int|null $rev_id The rev_id of the change to add the tags to
 650          * @param int|null $log_id The log_id of the change to add the tags to
 651          * @param string|null $params Params to put in the ct_params field of table
 652          * 'change_tag' when adding tags
 653          * @param string $reason Comment for the log
 654          * @param User $user Who to give credit for the action
 655          * @return Status If successful, the value of this Status object will be an
 656          * object (stdClass) with the following fields:
 657          *  - logId: the ID of the added log entry, or null if no log entry was added
 658          *    (i.e. no operation was performed)
 659          *  - addedTags: an array containing the tags that were actually added
 660          *  - removedTags: an array containing the tags that were actually removed
 661          * @since 1.25
 662          */
 663         public static function updateTagsWithChecks( $tagsToAdd, $tagsToRemove,
 664                 $rc_id, $rev_id, $log_id, $params, $reason, User $user
 665         ) {
 666                 if ( is_null( $tagsToAdd ) ) {
 667                         $tagsToAdd = [];
 668                 }
 669                 if ( is_null( $tagsToRemove ) ) {
 670                         $tagsToRemove = [];
 671                 }
 672                 if ( !$tagsToAdd && !$tagsToRemove ) {
 673                         // no-op, don't bother
 674                         return Status::newGood( (object)[
 675                                 'logId' => null,
 676                                 'addedTags' => [],
 677                                 'removedTags' => [],
 678                         ] );
 679                 }
 680
 681                 // are we allowed to do this?
 682                 $result = self::canUpdateTags( $tagsToAdd, $tagsToRemove, $user );
 683                 if ( !$result->isOK() ) {
 684                         $result->value = null;
 685                         return $result;
 686                 }
 687
 688                 // basic rate limiting
 689                 if ( $user->pingLimiter( 'changetag' ) ) {
 690                         return Status::newFatal( 'actionthrottledtext' );
 691                 }
 692
 693                 // do it!
 694                 list( $tagsAdded, $tagsRemoved, $initialTags ) = self::updateTags( $tagsToAdd,
 695                         $tagsToRemove, $rc_id, $rev_id, $log_id, $params, null, $user );
 696                 if ( !$tagsAdded && !$tagsRemoved ) {
 697                         // no-op, don't log it
 698                         return Status::newGood( (object)[
 699                                 'logId' => null,
 700                                 'addedTags' => [],
 701                                 'removedTags' => [],
 702                         ] );
 703                 }
 704
 705                 // log it
 706                 $logEntry = new ManualLogEntry( 'tag', 'update' );
 707                 $logEntry->setPerformer( $user );
 708                 $logEntry->setComment( $reason );
 709
 710                 // find the appropriate target page
 711                 if ( $rev_id ) {
 712                         $rev = Revision::newFromId( $rev_id );
 713                         if ( $rev ) {
 714                                 $logEntry->setTarget( $rev->getTitle() );
 715                         }
 716                 } elseif ( $log_id ) {
 717                         // This function is from revision deletion logic and has nothing to do with
 718                         // change tags, but it appears to be the only other place in core where we
 719                         // perform logged actions on log items.
 720                         $logEntry->setTarget( RevDelLogList::suggestTarget( null, [ $log_id ] ) );
 721                 }
 722
 723                 if ( !$logEntry->getTarget() ) {
 724                         // target is required, so we have to set something
 725                         $logEntry->setTarget( SpecialPage::getTitleFor( 'Tags' ) );
 726                 }
 727
 728                 $logParams = [
 729                         '4::revid' => $rev_id,
 730                         '5::logid' => $log_id,
 731                         '6:list:tagsAdded' => $tagsAdded,
 732                         '7:number:tagsAddedCount' => count( $tagsAdded ),
 733                         '8:list:tagsRemoved' => $tagsRemoved,
 734                         '9:number:tagsRemovedCount' => count( $tagsRemoved ),
 735                         'initialTags' => $initialTags,
 736                 ];
 737                 $logEntry->setParameters( $logParams );
 738                 $logEntry->setRelations( [ 'Tag' => array_merge( $tagsAdded, $tagsRemoved ) ] );
 739
 740                 $dbw = wfGetDB( DB_MASTER );
 741                 $logId = $logEntry->insert( $dbw );
 742                 // Only send this to UDP, not RC, similar to patrol events
 743                 $logEntry->publish( $logId, 'udp' );
 744
 745                 return Status::newGood( (object)[
 746                         'logId' => $logId,
 747                         'addedTags' => $tagsAdded,
 748                         'removedTags' => $tagsRemoved,
 749                 ] );
 750         }
 751
 752         /**
 753          * Applies all tags-related changes to a query.
 754          * Handles selecting tags, and filtering.
 755          * Needs $tables to be set up properly, so we can figure out which join conditions to use.
 756          *
 757          * WARNING: If $filter_tag contains more than one tag, this function will add DISTINCT,
 758          * which may cause performance problems for your query unless you put the ID field of your
 759          * table at the end of the ORDER BY, and set a GROUP BY equal to the ORDER BY. For example,
 760          * if you had ORDER BY foo_timestamp DESC, you will now need GROUP BY foo_timestamp, foo_id
 761          * ORDER BY foo_timestamp DESC, foo_id DESC.
 762          *
 763          * @param string|array &$tables Table names, see Database::select
 764          * @param string|array &$fields Fields used in query, see Database::select
 765          * @param string|array &$conds Conditions used in query, see Database::select
 766          * @param array &$join_conds Join conditions, see Database::select
 767          * @param string|array &$options Options, see Database::select
 768          * @param string|array $filter_tag Tag(s) to select on
 769          *
 770          * @throws MWException When unable to determine appropriate JOIN condition for tagging
 771          */
 772         public static function modifyDisplayQuery( &$tables, &$fields, &$conds,
 773                 &$join_conds, &$options, $filter_tag = ''
 774         ) {
 775                 global $wgUseTagFilter;
 776
 777                 // Normalize to arrays
 778                 $tables = (array)$tables;
 779                 $fields = (array)$fields;
 780                 $conds = (array)$conds;
 781                 $options = (array)$options;
 782
 783                 $fields['ts_tags'] = self::makeTagSummarySubquery( $tables );
 784
 785                 // Figure out which ID field to use
 786                 if ( in_array( 'recentchanges', $tables ) ) {
 787                         $join_cond = 'ct_rc_id=rc_id';
 788                 } elseif ( in_array( 'logging', $tables ) ) {
 789                         $join_cond = 'ct_log_id=log_id';
 790                 } elseif ( in_array( 'revision', $tables ) ) {
 791                         $join_cond = 'ct_rev_id=rev_id';
 792                 } elseif ( in_array( 'archive', $tables ) ) {
 793                         $join_cond = 'ct_rev_id=ar_rev_id';
 794                 } else {
 795                         throw new MWException( 'Unable to determine appropriate JOIN condition for tagging.' );
 796                 }
 797
 798                 if ( $wgUseTagFilter && $filter_tag ) {
 799                         // Somebody wants to filter on a tag.
 800                         // Add an INNER JOIN on change_tag
 801
 802                         $tables[] = 'change_tag';
 803                         $join_conds['change_tag'] = [ 'JOIN', $join_cond ];
 804                         $filterTagIds = [];
 805                         $changeTagDefStore = MediaWikiServices::getInstance()->getChangeTagDefStore();
 806                         foreach ( (array)$filter_tag as $filterTagName ) {
 807                                 try {
 808                                         $filterTagIds[] = $changeTagDefStore->getId( $filterTagName );
 809                                 } catch ( NameTableAccessException $exception ) {
 810                                         // Return nothing.
 811                                         $conds[] = '0';
 812                                         break;
 813                                 }
 814                         }
 815
 816                         if ( $filterTagIds !== [] ) {
 817                                 $conds['ct_tag_id'] = $filterTagIds;
 818                         }
 819
 820                         if (
 821                                 is_array( $filter_tag ) && count( $filter_tag ) > 1 &&
 822                                 !in_array( 'DISTINCT', $options )
 823                         ) {
 824                                 $options[] = 'DISTINCT';
 825                         }
 826                 }
 827         }
 828
 829         /**
 830          * Make the tag summary subquery based on the given tables and return it.
 831          *
 832          * @param string|array $tables Table names, see Database::select
 833          *
 834          * @return string tag summary subqeury
 835          * @throws MWException When unable to determine appropriate JOIN condition for tagging
 836          */
 837         public static function makeTagSummarySubquery( $tables ) {
 838                 // Normalize to arrays
 839                 $tables = (array)$tables;
 840
 841                 // Figure out which ID field to use
 842                 if ( in_array( 'recentchanges', $tables ) ) {
 843                         $join_cond = 'ct_rc_id=rc_id';
 844                 } elseif ( in_array( 'logging', $tables ) ) {
 845                         $join_cond = 'ct_log_id=log_id';
 846                 } elseif ( in_array( 'revision', $tables ) ) {
 847                         $join_cond = 'ct_rev_id=rev_id';
 848                 } elseif ( in_array( 'archive', $tables ) ) {
 849                         $join_cond = 'ct_rev_id=ar_rev_id';
 850                 } else {
 851                         throw new MWException( 'Unable to determine appropriate JOIN condition for tagging.' );
 852                 }
 853
 854                 $tagTables = [ 'change_tag', 'change_tag_def' ];
 855                 $join_cond_ts_tags = [ 'change_tag_def' => [ 'JOIN', 'ct_tag_id=ctd_id' ] ];
 856                 $field = 'ctd_name';
 857
 858                 return wfGetDB( DB_REPLICA )->buildGroupConcatField(
 859                         ',', $tagTables, $field, $join_cond, $join_cond_ts_tags
 860                 );
 861         }
 862
 863         /**
 864          * Build a text box to select a change tag
 865          *
 866          * @param string $selected Tag to select by default
 867          * @param bool $ooui Use an OOUI TextInputWidget as selector instead of a non-OOUI input field
 868          *        You need to call OutputPage::enableOOUI() yourself.
 869          * @param IContextSource|null $context
 870          * @note Even though it takes null as a valid argument, an IContextSource is preferred
 871          *       in a new code, as the null value can change in the future
 872          * @return array an array of (label, selector)
 873          */
 874         public static function buildTagFilterSelector(
 875                 $selected = '', $ooui = false, IContextSource $context = null
 876         ) {
 877                 if ( !$context ) {
 878                         $context = RequestContext::getMain();
 879                 }
 880
 881                 $config = $context->getConfig();
 882                 if ( !$config->get( 'UseTagFilter' ) || !count( self::listDefinedTags() ) ) {
 883                         return [];
 884                 }
 885
 886                 $data = [
 887                         Html::rawElement(
 888                                 'label',
 889                                 [ 'for' => 'tagfilter' ],
 890                                 $context->msg( 'tag-filter' )->parse()
 891                         )
 892                 ];
 893
 894                 if ( $ooui ) {
 895                         $data[] = new OOUI\TextInputWidget( [
 896                                 'id' => 'tagfilter',
 897                                 'name' => 'tagfilter',
 898                                 'value' => $selected,
 899                                 'classes' => 'mw-tagfilter-input',
 900                         ] );
 901                 } else {
 902                         $data[] = Xml::input(
 903                                 'tagfilter',
 904                                 20,
 905                                 $selected,
 906                                 [ 'class' => 'mw-tagfilter-input mw-ui-input mw-ui-input-inline', 'id' => 'tagfilter' ]
 907                         );
 908                 }
 909
 910                 return $data;
 911         }
 912
 913         /**
 914          * Set ctd_user_defined = 1 in change_tag_def without checking that the tag name is valid.
 915          * Extensions should NOT use this function; they can use the ListDefinedTags
 916          * hook instead.
 917          *
 918          * @param string $tag Tag to create
 919          * @since 1.25
 920          */
 921         public static function defineTag( $tag ) {
 922                 $dbw = wfGetDB( DB_MASTER );
 923                 $tagDef = [
 924                         'ctd_name' => $tag,
 925                         'ctd_user_defined' => 1,
 926                         'ctd_count' => 0
 927                 ];
 928                 $dbw->upsert(
 929                         'change_tag_def',
 930                         $tagDef,
 931                         [ 'ctd_name' ],
 932                         [ 'ctd_user_defined' => 1 ],
 933                         __METHOD__
 934                 );
 935
 936                 // clear the memcache of defined tags
 937                 self::purgeTagCacheAll();
 938         }
 939
 940         /**
 941          * Update ctd_user_defined = 0 field in change_tag_def.
 942          * The tag may remain in use by extensions, and may still show up as 'defined'
 943          * if an extension is setting it from the ListDefinedTags hook.
 944          *
 945          * @param string $tag Tag to remove
 946          * @since 1.25
 947          */
 948         public static function undefineTag( $tag ) {
 949                 $dbw = wfGetDB( DB_MASTER );
 950
 951                 $dbw->update(
 952                         'change_tag_def',
 953                         [ 'ctd_user_defined' => 0 ],
 954                         [ 'ctd_name' => $tag ],
 955                         __METHOD__
 956                 );
 957
 958                 $dbw->delete(
 959                         'change_tag_def',
 960                         [ 'ctd_name' => $tag, 'ctd_count' => 0 ],
 961                         __METHOD__
 962                 );
 963
 964                 // clear the memcache of defined tags
 965                 self::purgeTagCacheAll();
 966         }
 967
 968         /**
 969          * Writes a tag action into the tag management log.
 970          *
 971          * @param string $action
 972          * @param string $tag
 973          * @param string $reason
 974          * @param User $user Who to attribute the action to
 975          * @param int|null $tagCount For deletion only, how many usages the tag had before
 976          * it was deleted.
 977          * @param array $logEntryTags Change tags to apply to the entry
 978          * that will be created in the tag management log
 979          * @return int ID of the inserted log entry
 980          * @since 1.25
 981          */
 982         protected static function logTagManagementAction( $action, $tag, $reason,
 983                 User $user, $tagCount = null, array $logEntryTags = []
 984         ) {
 985                 $dbw = wfGetDB( DB_MASTER );
 986
 987                 $logEntry = new ManualLogEntry( 'managetags', $action );
 988                 $logEntry->setPerformer( $user );
 989                 // target page is not relevant, but it has to be set, so we just put in
 990                 // the title of Special:Tags
 991                 $logEntry->setTarget( Title::newFromText( 'Special:Tags' ) );
 992                 $logEntry->setComment( $reason );
 993
 994                 $params = [ '4::tag' => $tag ];
 995                 if ( !is_null( $tagCount ) ) {
 996                         $params['5:number:count'] = $tagCount;
 997                 }
 998                 $logEntry->setParameters( $params );
 999                 $logEntry->setRelations( [ 'Tag' => $tag ] );
1000                 $logEntry->addTags( $logEntryTags );
1001
1002                 $logId = $logEntry->insert( $dbw );
1003                 $logEntry->publish( $logId );
1004                 return $logId;
1005         }
1006
1007         /**
1008          * Is it OK to allow the user to activate this tag?
1009          *
1010          * @param string $tag Tag that you are interested in activating
1011          * @param User|null $user User whose permission you wish to check, or null if
1012          * you don't care (e.g. maintenance scripts)
1013          * @return Status
1014          * @since 1.25
1015          */
1016         public static function canActivateTag( $tag, User $user = null ) {
1017                 if ( !is_null( $user ) ) {
1018                         if ( !MediaWikiServices::getInstance()->getPermissionManager()
1019                                         ->userHasRight( $user, 'managechangetags' )
1020                         ) {
1021                                 return Status::newFatal( 'tags-manage-no-permission' );
1022                         } elseif ( $user->getBlock() && $user->getBlock()->isSitewide() ) {
1023                                 return Status::newFatal( 'tags-manage-blocked', $user->getName() );
1024                         }
1025                 }
1026
1027                 // defined tags cannot be activated (a defined tag is either extension-
1028                 // defined, in which case the extension chooses whether or not to active it;
1029                 // or user-defined, in which case it is considered active)
1030                 $definedTags = self::listDefinedTags();
1031                 if ( in_array( $tag, $definedTags ) ) {
1032                         return Status::newFatal( 'tags-activate-not-allowed', $tag );
1033                 }
1034
1035                 // non-existing tags cannot be activated
1036                 $tagUsage = self::tagUsageStatistics();
1037                 if ( !isset( $tagUsage[$tag] ) ) { // we already know the tag is undefined
1038                         return Status::newFatal( 'tags-activate-not-found', $tag );
1039                 }
1040
1041                 return Status::newGood();
1042         }
1043
1044         /**
1045          * Activates a tag, checking whether it is allowed first, and adding a log
1046          * entry afterwards.
1047          *
1048          * Includes a call to ChangeTag::canActivateTag(), so your code doesn't need
1049          * to do that.
1050          *
1051          * @param string $tag
1052          * @param string $reason
1053          * @param User $user Who to give credit for the action
1054          * @param bool $ignoreWarnings Can be used for API interaction, default false
1055          * @param array $logEntryTags Change tags to apply to the entry
1056          * that will be created in the tag management log
1057          * @return Status If successful, the Status contains the ID of the added log
1058          * entry as its value
1059          * @since 1.25
1060          */
1061         public static function activateTagWithChecks( $tag, $reason, User $user,
1062                 $ignoreWarnings = false, array $logEntryTags = []
1063         ) {
1064                 // are we allowed to do this?
1065                 $result = self::canActivateTag( $tag, $user );
1066                 if ( $ignoreWarnings ? !$result->isOK() : !$result->isGood() ) {
1067                         $result->value = null;
1068                         return $result;
1069                 }
1070
1071                 // do it!
1072                 self::defineTag( $tag );
1073
1074                 // log it
1075                 $logId = self::logTagManagementAction( 'activate', $tag, $reason, $user,
1076                         null, $logEntryTags );
1077
1078                 return Status::newGood( $logId );
1079         }
1080
1081         /**
1082          * Is it OK to allow the user to deactivate this tag?
1083          *
1084          * @param string $tag Tag that you are interested in deactivating
1085          * @param User|null $user User whose permission you wish to check, or null if
1086          * you don't care (e.g. maintenance scripts)
1087          * @return Status
1088          * @since 1.25
1089          */
1090         public static function canDeactivateTag( $tag, User $user = null ) {
1091                 if ( !is_null( $user ) ) {
1092                         if ( !MediaWikiServices::getInstance()->getPermissionManager()
1093                                         ->userHasRight( $user, 'managechangetags' )
1094                         ) {
1095                                 return Status::newFatal( 'tags-manage-no-permission' );
1096                         } elseif ( $user->getBlock() && $user->getBlock()->isSitewide() ) {
1097                                 return Status::newFatal( 'tags-manage-blocked', $user->getName() );
1098                         }
1099                 }
1100
1101                 // only explicitly-defined tags can be deactivated
1102                 $explicitlyDefinedTags = self::listExplicitlyDefinedTags();
1103                 if ( !in_array( $tag, $explicitlyDefinedTags ) ) {
1104                         return Status::newFatal( 'tags-deactivate-not-allowed', $tag );
1105                 }
1106                 return Status::newGood();
1107         }
1108
1109         /**
1110          * Deactivates a tag, checking whether it is allowed first, and adding a log
1111          * entry afterwards.
1112          *
1113          * Includes a call to ChangeTag::canDeactivateTag(), so your code doesn't need
1114          * to do that.
1115          *
1116          * @param string $tag
1117          * @param string $reason
1118          * @param User $user Who to give credit for the action
1119          * @param bool $ignoreWarnings Can be used for API interaction, default false
1120          * @param array $logEntryTags Change tags to apply to the entry
1121          * that will be created in the tag management log
1122          * @return Status If successful, the Status contains the ID of the added log
1123          * entry as its value
1124          * @since 1.25
1125          */
1126         public static function deactivateTagWithChecks( $tag, $reason, User $user,
1127                 $ignoreWarnings = false, array $logEntryTags = []
1128         ) {
1129                 // are we allowed to do this?
1130                 $result = self::canDeactivateTag( $tag, $user );
1131                 if ( $ignoreWarnings ? !$result->isOK() : !$result->isGood() ) {
1132                         $result->value = null;
1133                         return $result;
1134                 }
1135
1136                 // do it!
1137                 self::undefineTag( $tag );
1138
1139                 // log it
1140                 $logId = self::logTagManagementAction( 'deactivate', $tag, $reason, $user,
1141                         null, $logEntryTags );
1142
1143                 return Status::newGood( $logId );
1144         }
1145
1146         /**
1147          * Is the tag name valid?
1148          *
1149          * @param string $tag Tag that you are interested in creating
1150          * @return Status
1151          * @since 1.30
1152          */
1153         public static function isTagNameValid( $tag ) {
1154                 // no empty tags
1155                 if ( $tag === '' ) {
1156                         return Status::newFatal( 'tags-create-no-name' );
1157                 }
1158
1159                 // tags cannot contain commas (used to be used as a delimiter in tag_summary table),
1160                 // pipe (used as a delimiter between multiple tags in
1161                 // SpecialRecentchanges and friends), or slashes (would break tag description messages in
1162                 // MediaWiki namespace)
1163                 if ( strpos( $tag, ',' ) !== false || strpos( $tag, '|' ) !== false
1164                         || strpos( $tag, '/' ) !== false ) {
1165                         return Status::newFatal( 'tags-create-invalid-chars' );
1166                 }
1167
1168                 // could the MediaWiki namespace description messages be created?
1169                 $title = Title::makeTitleSafe( NS_MEDIAWIKI, "Tag-$tag-description" );
1170                 if ( is_null( $title ) ) {
1171                         return Status::newFatal( 'tags-create-invalid-title-chars' );
1172                 }
1173
1174                 return Status::newGood();
1175         }
1176
1177         /**
1178          * Is it OK to allow the user to create this tag?
1179          *
1180          * Extensions should NOT use this function. In most cases, a tag can be
1181          * defined using the ListDefinedTags hook without any checking.
1182          *
1183          * @param string $tag Tag that you are interested in creating
1184          * @param User|null $user User whose permission you wish to check, or null if
1185          * you don't care (e.g. maintenance scripts)
1186          * @return Status
1187          * @since 1.25
1188          */
1189         public static function canCreateTag( $tag, User $user = null ) {
1190                 if ( !is_null( $user ) ) {
1191                         if ( !MediaWikiServices::getInstance()->getPermissionManager()
1192                                         ->userHasRight( $user, 'managechangetags' )
1193                         ) {
1194                                 return Status::newFatal( 'tags-manage-no-permission' );
1195                         } elseif ( $user->getBlock() && $user->getBlock()->isSitewide() ) {
1196                                 return Status::newFatal( 'tags-manage-blocked', $user->getName() );
1197                         }
1198                 }
1199
1200                 $status = self::isTagNameValid( $tag );
1201                 if ( !$status->isGood() ) {
1202                         return $status;
1203                 }
1204
1205                 // does the tag already exist?
1206                 $tagUsage = self::tagUsageStatistics();
1207                 if ( isset( $tagUsage[$tag] ) || in_array( $tag, self::listDefinedTags() ) ) {
1208                         return Status::newFatal( 'tags-create-already-exists', $tag );
1209                 }
1210
1211                 // check with hooks
1212                 $canCreateResult = Status::newGood();
1213                 Hooks::run( 'ChangeTagCanCreate', [ $tag, $user, &$canCreateResult ] );
1214                 return $canCreateResult;
1215         }
1216
1217         /**
1218          * Creates a tag by adding it to `change_tag_def` table.
1219          *
1220          * Extensions should NOT use this function; they can use the ListDefinedTags
1221          * hook instead.
1222          *
1223          * Includes a call to ChangeTag::canCreateTag(), so your code doesn't need to
1224          * do that.
1225          *
1226          * @param string $tag
1227          * @param string $reason
1228          * @param User $user Who to give credit for the action
1229          * @param bool $ignoreWarnings Can be used for API interaction, default false
1230          * @param array $logEntryTags Change tags to apply to the entry
1231          * that will be created in the tag management log
1232          * @return Status If successful, the Status contains the ID of the added log
1233          * entry as its value
1234          * @since 1.25
1235          */
1236         public static function createTagWithChecks( $tag, $reason, User $user,
1237                 $ignoreWarnings = false, array $logEntryTags = []
1238         ) {
1239                 // are we allowed to do this?
1240                 $result = self::canCreateTag( $tag, $user );
1241                 if ( $ignoreWarnings ? !$result->isOK() : !$result->isGood() ) {
1242                         $result->value = null;
1243                         return $result;
1244                 }
1245
1246                 // do it!
1247                 self::defineTag( $tag );
1248
1249                 // log it
1250                 $logId = self::logTagManagementAction( 'create', $tag, $reason, $user,
1251                         null, $logEntryTags );
1252
1253                 return Status::newGood( $logId );
1254         }
1255
1256         /**
1257          * Permanently removes all traces of a tag from the DB. Good for removing
1258          * misspelt or temporary tags.
1259          *
1260          * This function should be directly called by maintenance scripts only, never
1261          * by user-facing code. See deleteTagWithChecks() for functionality that can
1262          * safely be exposed to users.
1263          *
1264          * @param string $tag Tag to remove
1265          * @return Status The returned status will be good unless a hook changed it
1266          * @since 1.25
1267          */
1268         public static function deleteTagEverywhere( $tag ) {
1269                 $dbw = wfGetDB( DB_MASTER );
1270                 $dbw->startAtomic( __METHOD__ );
1271
1272                 // fetch tag id, this must be done before calling undefineTag(), see T225564
1273                 $tagId = MediaWikiServices::getInstance()->getChangeTagDefStore()->getId( $tag );
1274
1275                 // set ctd_user_defined = 0
1276                 self::undefineTag( $tag );
1277
1278                 // delete from change_tag
1279                 $dbw->delete( 'change_tag', [ 'ct_tag_id' => $tagId ], __METHOD__ );
1280                 $dbw->delete( 'change_tag_def', [ 'ctd_name' => $tag ], __METHOD__ );
1281                 $dbw->endAtomic( __METHOD__ );
1282
1283                 // give extensions a chance
1284                 $status = Status::newGood();
1285                 Hooks::run( 'ChangeTagAfterDelete', [ $tag, &$status ] );
1286                 // let's not allow error results, as the actual tag deletion succeeded
1287                 if ( !$status->isOK() ) {
1288                         wfDebug( 'ChangeTagAfterDelete error condition downgraded to warning' );
1289                         $status->setOK( true );
1290                 }
1291
1292                 // clear the memcache of defined tags
1293                 self::purgeTagCacheAll();
1294
1295                 return $status;
1296         }
1297
1298         /**
1299          * Is it OK to allow the user to delete this tag?
1300          *
1301          * @param string $tag Tag that you are interested in deleting
1302          * @param User|null $user User whose permission you wish to check, or null if
1303          * you don't care (e.g. maintenance scripts)
1304          * @return Status
1305          * @since 1.25
1306          */
1307         public static function canDeleteTag( $tag, User $user = null ) {
1308                 $tagUsage = self::tagUsageStatistics();
1309
1310                 if ( !is_null( $user ) ) {
1311                         if ( !MediaWikiServices::getInstance()->getPermissionManager()
1312                                         ->userHasRight( $user, 'deletechangetags' )
1313                         ) {
1314                                 return Status::newFatal( 'tags-delete-no-permission' );
1315                         } elseif ( $user->getBlock() && $user->getBlock()->isSitewide() ) {
1316                                 return Status::newFatal( 'tags-manage-blocked', $user->getName() );
1317                         }
1318                 }
1319
1320                 if ( !isset( $tagUsage[$tag] ) && !in_array( $tag, self::listDefinedTags() ) ) {
1321                         return Status::newFatal( 'tags-delete-not-found', $tag );
1322                 }
1323
1324                 if ( isset( $tagUsage[$tag] ) && $tagUsage[$tag] > self::MAX_DELETE_USES ) {
1325                         return Status::newFatal( 'tags-delete-too-many-uses', $tag, self::MAX_DELETE_USES );
1326                 }
1327
1328                 $softwareDefined = self::listSoftwareDefinedTags();
1329                 if ( in_array( $tag, $softwareDefined ) ) {
1330                         // extension-defined tags can't be deleted unless the extension
1331                         // specifically allows it
1332                         $status = Status::newFatal( 'tags-delete-not-allowed' );
1333                 } else {
1334                         // user-defined tags are deletable unless otherwise specified
1335                         $status = Status::newGood();
1336                 }
1337
1338                 Hooks::run( 'ChangeTagCanDelete', [ $tag, $user, &$status ] );
1339                 return $status;
1340         }
1341
1342         /**
1343          * Deletes a tag, checking whether it is allowed first, and adding a log entry
1344          * afterwards.
1345          *
1346          * Includes a call to ChangeTag::canDeleteTag(), so your code doesn't need to
1347          * do that.
1348          *
1349          * @param string $tag
1350          * @param string $reason
1351          * @param User $user Who to give credit for the action
1352          * @param bool $ignoreWarnings Can be used for API interaction, default false
1353          * @param array $logEntryTags Change tags to apply to the entry
1354          * that will be created in the tag management log
1355          * @return Status If successful, the Status contains the ID of the added log
1356          * entry as its value
1357          * @since 1.25
1358          */
1359         public static function deleteTagWithChecks( $tag, $reason, User $user,
1360                 $ignoreWarnings = false, array $logEntryTags = []
1361         ) {
1362                 // are we allowed to do this?
1363                 $result = self::canDeleteTag( $tag, $user );
1364                 if ( $ignoreWarnings ? !$result->isOK() : !$result->isGood() ) {
1365                         $result->value = null;
1366                         return $result;
1367                 }
1368
1369                 // store the tag usage statistics
1370                 $tagUsage = self::tagUsageStatistics();
1371                 $hitcount = $tagUsage[$tag] ?? 0;
1372
1373                 // do it!
1374                 $deleteResult = self::deleteTagEverywhere( $tag );
1375                 if ( !$deleteResult->isOK() ) {
1376                         return $deleteResult;
1377                 }
1378
1379                 // log it
1380                 $logId = self::logTagManagementAction( 'delete', $tag, $reason, $user,
1381                         $hitcount, $logEntryTags );
1382
1383                 $deleteResult->value = $logId;
1384                 return $deleteResult;
1385         }
1386
1387         /**
1388          * Lists those tags which core or extensions report as being "active".
1389          *
1390          * @return array
1391          * @since 1.25
1392          */
1393         public static function listSoftwareActivatedTags() {
1394                 // core active tags
1395                 $tags = self::getSoftwareTags();
1396                 if ( !Hooks::isRegistered( 'ChangeTagsListActive' ) ) {
1397                         return $tags;
1398                 }
1399                 $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
1400                 return $cache->getWithSetCallback(
1401                         $cache->makeKey( 'active-tags' ),
1402                         WANObjectCache::TTL_MINUTE * 5,
1403                         function ( $oldValue, &$ttl, array &$setOpts ) use ( $tags ) {
1404                                 $setOpts += Database::getCacheSetOptions( wfGetDB( DB_REPLICA ) );
1405
1406                                 // Ask extensions which tags they consider active
1407                                 Hooks::run( 'ChangeTagsListActive', [ &$tags ] );
1408                                 return $tags;
1409                         },
1410                         [
1411                                 'checkKeys' => [ $cache->makeKey( 'active-tags' ) ],
1412                                 'lockTSE' => WANObjectCache::TTL_MINUTE * 5,
1413                                 'pcTTL' => WANObjectCache::TTL_PROC_LONG
1414                         ]
1415                 );
1416         }
1417
1418         /**
1419          * Basically lists defined tags which count even if they aren't applied to anything.
1420          * It returns a union of the results of listExplicitlyDefinedTags()
1421          *
1422          * @return string[] Array of strings: tags
1423          */
1424         public static function listDefinedTags() {
1425                 $tags1 = self::listExplicitlyDefinedTags();
1426                 $tags2 = self::listSoftwareDefinedTags();
1427                 return array_values( array_unique( array_merge( $tags1, $tags2 ) ) );
1428         }
1429
1430         /**
1431          * Lists tags explicitly defined in the `change_tag_def` table of the database.
1432          *
1433          * Tries memcached first.
1434          *
1435          * @return string[] Array of strings: tags
1436          * @since 1.25
1437          */
1438         public static function listExplicitlyDefinedTags() {
1439                 $fname = __METHOD__;
1440
1441                 $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
1442                 return $cache->getWithSetCallback(
1443                         $cache->makeKey( 'valid-tags-db' ),
1444                         WANObjectCache::TTL_MINUTE * 5,
1445                         function ( $oldValue, &$ttl, array &$setOpts ) use ( $fname ) {
1446                                 $dbr = wfGetDB( DB_REPLICA );
1447
1448                                 $setOpts += Database::getCacheSetOptions( $dbr );
1449
1450                                 $tags = $dbr->selectFieldValues(
1451                                         'change_tag_def',
1452                                         'ctd_name',
1453                                         [ 'ctd_user_defined' => 1 ],
1454                                         $fname
1455                                 );
1456
1457                                 return array_filter( array_unique( $tags ) );
1458                         },
1459                         [
1460                                 'checkKeys' => [ $cache->makeKey( 'valid-tags-db' ) ],
1461                                 'lockTSE' => WANObjectCache::TTL_MINUTE * 5,
1462                                 'pcTTL' => WANObjectCache::TTL_PROC_LONG
1463                         ]
1464                 );
1465         }
1466
1467         /**
1468          * Lists tags defined by core or extensions using the ListDefinedTags hook.
1469          * Extensions need only define those tags they deem to be in active use.
1470          *
1471          * Tries memcached first.
1472          *
1473          * @return string[] Array of strings: tags
1474          * @since 1.25
1475          */
1476         public static function listSoftwareDefinedTags() {
1477                 // core defined tags
1478                 $tags = self::getSoftwareTags( true );
1479                 if ( !Hooks::isRegistered( 'ListDefinedTags' ) ) {
1480                         return $tags;
1481                 }
1482                 $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
1483                 return $cache->getWithSetCallback(
1484                         $cache->makeKey( 'valid-tags-hook' ),
1485                         WANObjectCache::TTL_MINUTE * 5,
1486                         function ( $oldValue, &$ttl, array &$setOpts ) use ( $tags ) {
1487                                 $setOpts += Database::getCacheSetOptions( wfGetDB( DB_REPLICA ) );
1488
1489                                 Hooks::run( 'ListDefinedTags', [ &$tags ] );
1490                                 return array_filter( array_unique( $tags ) );
1491                         },
1492                         [
1493                                 'checkKeys' => [ $cache->makeKey( 'valid-tags-hook' ) ],
1494                                 'lockTSE' => WANObjectCache::TTL_MINUTE * 5,
1495                                 'pcTTL' => WANObjectCache::TTL_PROC_LONG
1496                         ]
1497                 );
1498         }
1499
1500         /**
1501          * Invalidates the short-term cache of defined tags used by the
1502          * list*DefinedTags functions, as well as the tag statistics cache.
1503          * @since 1.25
1504          */
1505         public static function purgeTagCacheAll() {
1506                 $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
1507
1508                 $cache->touchCheckKey( $cache->makeKey( 'active-tags' ) );
1509                 $cache->touchCheckKey( $cache->makeKey( 'valid-tags-db' ) );
1510                 $cache->touchCheckKey( $cache->makeKey( 'valid-tags-hook' ) );
1511                 $cache->touchCheckKey( $cache->makeKey( 'tags-usage-statistics' ) );
1512
1513                 MediaWikiServices::getInstance()->getChangeTagDefStore()->reloadMap();
1514         }
1515
1516         /**
1517          * Returns a map of any tags used on the wiki to number of edits
1518          * tagged with them, ordered descending by the hitcount.
1519          * This does not include tags defined somewhere that have never been applied.
1520          * @return array Array of string => int
1521          */
1522         public static function tagUsageStatistics() {
1523                 $fname = __METHOD__;
1524
1525                 $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
1526                 return $cache->getWithSetCallback(
1527                         $cache->makeKey( 'tags-usage-statistics' ),
1528                         WANObjectCache::TTL_MINUTE * 5,
1529                         function ( $oldValue, &$ttl, array &$setOpts ) use ( $fname ) {
1530                                 $dbr = wfGetDB( DB_REPLICA );
1531                                 $res = $dbr->select(
1532                                         'change_tag_def',
1533                                         [ 'ctd_name', 'ctd_count' ],
1534                                         [],
1535                                         $fname,
1536                                         [ 'ORDER BY' => 'ctd_count DESC' ]
1537                                 );
1538
1539                                 $out = [];
1540                                 foreach ( $res as $row ) {
1541                                         $out[$row->ctd_name] = $row->ctd_count;
1542                                 }
1543
1544                                 return $out;
1545                         },
1546                         [
1547                                 'checkKeys' => [ $cache->makeKey( 'tags-usage-statistics' ) ],
1548                                 'lockTSE' => WANObjectCache::TTL_MINUTE * 5,
1549                                 'pcTTL' => WANObjectCache::TTL_PROC_LONG
1550                         ]
1551                 );
1552         }
1553
1554         /**
1555          * Indicate whether change tag editing UI is relevant
1556          *
1557          * Returns true if the user has the necessary right and there are any
1558          * editable tags defined.
1559          *
1560          * This intentionally doesn't check "any addable || any deletable", because
1561          * it seems like it would be more confusing than useful if the checkboxes
1562          * suddenly showed up because some abuse filter stopped defining a tag and
1563          * then suddenly disappeared when someone deleted all uses of that tag.
1564          *
1565          * @param User $user
1566          * @return bool
1567          */
1568         public static function showTagEditingUI( User $user ) {
1569                 return MediaWikiServices::getInstance()->getPermissionManager()
1570                                    ->userHasRight( $user, 'changetags' ) &&
1571                            (bool)self::listExplicitlyDefinedTags();
1572         }
1573 }