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
  28 class ChangeTags {
  29         /**
  30          * Can't delete tags with more than this many uses. Similar in intent to
  31          * the bigdelete user right
  32          * @todo Use the job queue for tag deletion to avoid this restriction
  33          */
  34         const MAX_DELETE_USES = 5000;
  35
  36         /**
  37          * A list of tags defined and used by MediaWiki itself.
  38          */
  39         private static $definedSoftwareTags = [
  40                 'mw-contentmodelchange',
  41                 'mw-new-redirect',
  42                 'mw-removed-redirect',
  43                 'mw-changed-redirect-target',
  44                 'mw-blank',
  45                 'mw-replace',
  46                 'mw-rollback',
  47                 'mw-undo',
  48         ];
  49
  50         /**
  51          * Loads defined core tags, checks for invalid types (if not array),
  52          * and filters for supported and enabled (if $all is false) tags only.
  53          *
  54          * @param bool $all If true, return all valid defined tags. Otherwise, return only enabled ones.
  55          * @return array Array of all defined/enabled tags.
  56          */
  57         public static function getSoftwareTags( $all = false ) {
  58                 global $wgSoftwareTags;
  59                 $softwareTags = [];
  60
  61                 if ( !is_array( $wgSoftwareTags ) ) {
  62                         wfWarn( 'wgSoftwareTags should be associative array of enabled tags.
  63                         Please refer to documentation for the list of tags you can enable' );
  64                         return $softwareTags;
  65                 }
  66
  67                 $availableSoftwareTags = !$all ?
  68                         array_keys( array_filter( $wgSoftwareTags ) ) :
  69                         array_keys( $wgSoftwareTags );
  70
  71                 $softwareTags = array_intersect(
  72                         $availableSoftwareTags,
  73                         self::$definedSoftwareTags
  74                 );
  75
  76                 return $softwareTags;
  77         }
  78
  79         /**
  80          * Creates HTML for the given tags
  81          *
  82          * @param string $tags Comma-separated list of tags
  83          * @param string $page A label for the type of action which is being displayed,
  84          *   for example: 'history', 'contributions' or 'newpages'
  85          * @param IContextSource|null $context
  86          * @note Even though it takes null as a valid argument, an IContextSource is preferred
  87          *       in a new code, as the null value is subject to change in the future
  88          * @return array Array with two items: (html, classes)
  89          *   - html: String: HTML for displaying the tags (empty string when param $tags is empty)
  90          *   - classes: Array of strings: CSS classes used in the generated html, one class for each tag
  91          * @return-taint onlysafefor_htmlnoent
  92          */
  93         public static function formatSummaryRow( $tags, $page, IContextSource $context = null ) {
  94                 if ( !$tags ) {
  95                         return [ '', [] ];
  96                 }
  97                 if ( !$context ) {
  98                         $context = RequestContext::getMain();
  99                 }
 100
 101                 $classes = [];
 102
 103                 $tags = explode( ',', $tags );
 104                 $displayTags = [];
 105                 foreach ( $tags as $tag ) {
 106                         if ( !$tag ) {
 107                                 continue;
 108                         }
 109                         $description = self::tagDescription( $tag, $context );
 110                         if ( $description === false ) {
 111                                 continue;
 112                         }
 113                         $displayTags[] = Xml::tags(
 114                                 'span',
 115                                 [ 'class' => 'mw-tag-marker ' .
 116                                                                 Sanitizer::escapeClass( "mw-tag-marker-$tag" ) ],
 117                                 $description
 118                         );
 119                         $classes[] = Sanitizer::escapeClass( "mw-tag-$tag" );
 120                 }
 121
 122                 if ( !$displayTags ) {
 123                         return [ '', [] ];
 124                 }
 125
 126                 $markers = $context->msg( 'tag-list-wrapper' )
 127                         ->numParams( count( $displayTags ) )
 128                         ->rawParams( $context->getLanguage()->commaList( $displayTags ) )
 129                         ->parse();
 130                 $markers = Xml::tags( 'span', [ 'class' => 'mw-tag-markers' ], $markers );
 131
 132                 return [ $markers, $classes ];
 133         }
 134
 135         /**
 136          * Get a short description for a tag.
 137          *
 138          * Checks if message key "mediawiki:tag-$tag" exists. If it does not,
 139          * returns the HTML-escaped tag name. Uses the message if the message
 140          * exists, provided it is not disabled. If the message is disabled,
 141          * we consider the tag hidden, and return false.
 142          *
 143          * @param string $tag
 144          * @param MessageLocalizer $context
 145          * @return string|bool Tag description or false if tag is to be hidden.
 146          * @since 1.25 Returns false if tag is to be hidden.
 147          */
 148         public static function tagDescription( $tag, MessageLocalizer $context ) {
 149                 $msg = $context->msg( "tag-$tag" );
 150                 if ( !$msg->exists() ) {
 151                         // No such message, so return the HTML-escaped tag name.
 152                         return htmlspecialchars( $tag );
 153                 }
 154                 if ( $msg->isDisabled() ) {
 155                         // The message exists but is disabled, hide the tag.
 156                         return false;
 157                 }
 158
 159                 // Message exists and isn't disabled, use it.
 160                 return $msg->parse();
 161         }
 162
 163         /**
 164          * Get the message object for the tag's long description.
 165          *
 166          * Checks if message key "mediawiki:tag-$tag-description" exists. If it does not,
 167          * or if message is disabled, returns false. Otherwise, returns the message object
 168          * for the long description.
 169          *
 170          * @param string $tag
 171          * @param MessageLocalizer $context
 172          * @return Message|bool Message object of the tag long description or false if
 173          *  there is no description.
 174          */
 175         public static function tagLongDescriptionMessage( $tag, MessageLocalizer $context ) {
 176                 $msg = $context->msg( "tag-$tag-description" );
 177                 if ( !$msg->exists() ) {
 178                         return false;
 179                 }
 180                 if ( $msg->isDisabled() ) {
 181                         // The message exists but is disabled, hide the description.
 182                         return false;
 183                 }
 184
 185                 // Message exists and isn't disabled, use it.
 186                 return $msg;
 187         }
 188
 189         /**
 190          * Get truncated message for the tag's long description.
 191          *
 192          * @param string $tag Tag name.
 193          * @param int $length Maximum length of truncated message, including ellipsis.
 194          * @param IContextSource $context
 195          *
 196          * @return string Truncated long tag description.
 197          */
 198         public static function truncateTagDescription( $tag, $length, IContextSource $context ) {
 199                 // FIXME: Make this accept MessageLocalizer and Language instead of IContextSource
 200
 201                 $originalDesc = self::tagLongDescriptionMessage( $tag, $context );
 202                 // If there is no tag description, return empty string
 203                 if ( !$originalDesc ) {
 204                         return '';
 205                 }
 206
 207                 $taglessDesc = Sanitizer::stripAllTags( $originalDesc->parse() );
 208
 209                 return $context->getLanguage()->truncateForVisual( $taglessDesc, $length );
 210         }
 211
 212         /**
 213          * Add tags to a change given its rc_id, rev_id and/or log_id
 214          *
 215          * @param string|string[] $tags Tags to add to the change
 216          * @param int|null $rc_id The rc_id of the change to add the tags to
 217          * @param int|null $rev_id The rev_id of the change to add the tags to
 218          * @param int|null $log_id The log_id of the change to add the tags to
 219          * @param string|null $params Params to put in the ct_params field of table 'change_tag'
 220          * @param RecentChange|null $rc Recent change, in case the tagging accompanies the action
 221          * (this should normally be the case)
 222          *
 223          * @throws MWException
 224          * @return bool False if no changes are made, otherwise true
 225          */
 226         public static function addTags( $tags, $rc_id = null, $rev_id = null,
 227                 $log_id = null, $params = null, RecentChange $rc = null
 228         ) {
 229                 $result = self::updateTags( $tags, null, $rc_id, $rev_id, $log_id, $params, $rc );
 230                 return (bool)$result[0];
 231         }
 232
 233         /**
 234          * Add and remove tags to/from a change given its rc_id, rev_id and/or log_id,
 235          * without verifying that the tags exist or are valid. If a tag is present in
 236          * both $tagsToAdd and $tagsToRemove, it will be removed.
 237          *
 238          * This function should only be used by extensions to manipulate tags they
 239          * have registered using the ListDefinedTags hook. When dealing with user
 240          * input, call updateTagsWithChecks() instead.
 241          *
 242          * @param string|array|null $tagsToAdd Tags to add to the change
 243          * @param string|array|null $tagsToRemove Tags to remove from the change
 244          * @param int|null &$rc_id The rc_id of the change to add the tags to.
 245          * Pass a variable whose value is null if the rc_id is not relevant or unknown.
 246          * @param int|null &$rev_id The rev_id of the change to add the tags to.
 247          * Pass a variable whose value is null if the rev_id is not relevant or unknown.
 248          * @param int|null &$log_id The log_id of the change to add the tags to.
 249          * Pass a variable whose value is null if the log_id is not relevant or unknown.
 250          * @param string|null $params Params to put in the ct_params field of table
 251          * 'change_tag' when adding tags
 252          * @param RecentChange|null $rc Recent change being tagged, in case the tagging accompanies
 253          * the action
 254          * @param User|null $user Tagging user, in case the tagging is subsequent to the tagged action
 255          *
 256          * @throws MWException When $rc_id, $rev_id and $log_id are all null
 257          * @return array Index 0 is an array of tags actually added, index 1 is an
 258          * array of tags actually removed, index 2 is an array of tags present on the
 259          * revision or log entry before any changes were made
 260          *
 261          * @since 1.25
 262          */
 263         public static function updateTags( $tagsToAdd, $tagsToRemove, &$rc_id = null,
 264                 &$rev_id = null, &$log_id = null, $params = null, RecentChange $rc = null,
 265                 User $user = null
 266         ) {
 267                 $tagsToAdd = array_filter( (array)$tagsToAdd ); // Make sure we're submitting all tags...
 268                 $tagsToRemove = array_filter( (array)$tagsToRemove );
 269
 270                 if ( !$rc_id && !$rev_id && !$log_id ) {
 271                         throw new MWException( 'At least one of: RCID, revision ID, and log ID MUST be ' .
 272                                 'specified when adding or removing a tag from a change!' );
 273                 }
 274
 275                 $dbw = wfGetDB( DB_MASTER );
 276
 277                 // Might as well look for rcids and so on.
 278                 if ( !$rc_id ) {
 279                         // Info might be out of date, somewhat fractionally, on replica DB.
 280                         // LogEntry/LogPage and WikiPage match rev/log/rc timestamps,
 281                         // so use that relation to avoid full table scans.
 282                         if ( $log_id ) {
 283                                 $rc_id = $dbw->selectField(
 284                                         [ 'logging', 'recentchanges' ],
 285                                         'rc_id',
 286                                         [
 287                                                 'log_id' => $log_id,
 288                                                 'rc_timestamp = log_timestamp',
 289                                                 'rc_logid = log_id'
 290                                         ],
 291                                         __METHOD__
 292                                 );
 293                         } elseif ( $rev_id ) {
 294                                 $rc_id = $dbw->selectField(
 295                                         [ 'revision', 'recentchanges' ],
 296                                         'rc_id',
 297                                         [
 298                                                 'rev_id' => $rev_id,
 299                                                 'rc_timestamp = rev_timestamp',
 300                                                 'rc_this_oldid = rev_id'
 301                                         ],
 302                                         __METHOD__
 303                                 );
 304                         }
 305                 } elseif ( !$log_id && !$rev_id ) {
 306                         // Info might be out of date, somewhat fractionally, on replica DB.
 307                         $log_id = $dbw->selectField(
 308                                 'recentchanges',
 309                                 'rc_logid',
 310                                 [ 'rc_id' => $rc_id ],
 311                                 __METHOD__
 312                         );
 313                         $rev_id = $dbw->selectField(
 314                                 'recentchanges',
 315                                 'rc_this_oldid',
 316                                 [ 'rc_id' => $rc_id ],
 317                                 __METHOD__
 318                         );
 319                 }
 320
 321                 if ( $log_id && !$rev_id ) {
 322                         $rev_id = $dbw->selectField(
 323                                 'log_search',
 324                                 'ls_value',
 325                                 [ 'ls_field' => 'associated_rev_id', 'ls_log_id' => $log_id ],
 326                                 __METHOD__
 327                         );
 328                 } elseif ( !$log_id && $rev_id ) {
 329                         $log_id = $dbw->selectField(
 330                                 'log_search',
 331                                 'ls_log_id',
 332                                 [ 'ls_field' => 'associated_rev_id', 'ls_value' => $rev_id ],
 333                                 __METHOD__
 334                         );
 335                 }
 336
 337                 $prevTags = self::getPrevTags( $rc_id, $log_id, $rev_id );
 338
 339                 // add tags
 340                 $tagsToAdd = array_values( array_diff( $tagsToAdd, $prevTags ) );
 341                 $newTags = array_unique( array_merge( $prevTags, $tagsToAdd ) );
 342
 343                 // remove tags
 344                 $tagsToRemove = array_values( array_intersect( $tagsToRemove, $newTags ) );
 345                 $newTags = array_values( array_diff( $newTags, $tagsToRemove ) );
 346
 347                 sort( $prevTags );
 348                 sort( $newTags );
 349                 if ( $prevTags == $newTags ) {
 350                         return [ [], [], $prevTags ];
 351                 }
 352
 353                 // insert a row into change_tag for each new tag
 354                 $changeTagDefStore = MediaWikiServices::getInstance()->getChangeTagDefStore();
 355                 if ( count( $tagsToAdd ) ) {
 356                         $changeTagMapping = [];
 357                         foreach ( $tagsToAdd as $tag ) {
 358                                 $changeTagMapping[$tag] = $changeTagDefStore->acquireId( $tag );
 359                         }
 360                         $fname = __METHOD__;
 361                         // T207881: update the counts at the end of the transaction
 362                         $dbw->onTransactionPreCommitOrIdle( function () use ( $dbw, $tagsToAdd, $fname ) {
 363                                 $dbw->update(
 364                                         'change_tag_def',
 365                                         [ 'ctd_count = ctd_count + 1' ],
 366                                         [ 'ctd_name' => $tagsToAdd ],
 367                                         $fname
 368                                 );
 369                         } );
 370
 371                         $tagsRows = [];
 372                         foreach ( $tagsToAdd as $tag ) {
 373                                 // Filter so we don't insert NULLs as zero accidentally.
 374                                 // Keep in mind that $rc_id === null means "I don't care/know about the
 375                                 // rc_id, just delete $tag on this revision/log entry". It doesn't
 376                                 // mean "only delete tags on this revision/log WHERE rc_id IS NULL".
 377                                 $tagsRows[] = array_filter(
 378                                         [
 379                                                 'ct_rc_id' => $rc_id,
 380                                                 'ct_log_id' => $log_id,
 381                                                 'ct_rev_id' => $rev_id,
 382                                                 'ct_params' => $params,
 383                                                 'ct_tag_id' => $changeTagMapping[$tag] ?? null,
 384                                         ]
 385                                 );
 386
 387                         }
 388
 389                         $dbw->insert( 'change_tag', $tagsRows, __METHOD__, [ 'IGNORE' ] );
 390                 }
 391
 392                 // delete from change_tag
 393                 if ( count( $tagsToRemove ) ) {
 394                         $fname = __METHOD__;
 395                         foreach ( $tagsToRemove as $tag ) {
 396                                 $conds = array_filter(
 397                                         [
 398                                                 'ct_rc_id' => $rc_id,
 399                                                 'ct_log_id' => $log_id,
 400                                                 'ct_rev_id' => $rev_id,
 401                                                 'ct_tag_id' => $changeTagDefStore->getId( $tag ),
 402                                         ]
 403                                 );
 404                                 $dbw->delete( 'change_tag', $conds, __METHOD__ );
 405                                 if ( $dbw->affectedRows() ) {
 406                                         // T207881: update the counts at the end of the transaction
 407                                         $dbw->onTransactionPreCommitOrIdle( function () use ( $dbw, $tag, $fname ) {
 408                                                 $dbw->update(
 409                                                         'change_tag_def',
 410                                                         [ 'ctd_count = ctd_count - 1' ],
 411                                                         [ 'ctd_name' => $tag ],
 412                                                         $fname
 413                                                 );
 414
 415                                                 $dbw->delete(
 416                                                         'change_tag_def',
 417                                                         [ 'ctd_name' => $tag, 'ctd_count' => 0, 'ctd_user_defined' => 0 ],
 418                                                         $fname
 419                                                 );
 420                                         } );
 421                                 }
 422                         }
 423                 }
 424
 425                 Hooks::run( 'ChangeTagsAfterUpdateTags', [ $tagsToAdd, $tagsToRemove, $prevTags,
 426                         $rc_id, $rev_id, $log_id, $params, $rc, $user ] );
 427
 428                 return [ $tagsToAdd, $tagsToRemove, $prevTags ];
 429         }
 430
 431         private static function getPrevTags( $rc_id = null, $log_id = null, $rev_id = null ) {
 432                 $conds = array_filter(
 433                         [
 434                                 'ct_rc_id' => $rc_id,
 435                                 'ct_log_id' => $log_id,
 436                                 'ct_rev_id' => $rev_id,
 437                         ]
 438                 );
 439
 440                 $dbw = wfGetDB( DB_MASTER );
 441                 $tagIds = $dbw->selectFieldValues( 'change_tag', 'ct_tag_id', $conds, __METHOD__ );
 442
 443                 $tags = [];
 444                 foreach ( $tagIds as $tagId ) {
 445                         $tags[] = MediaWikiServices::getInstance()->getChangeTagDefStore()->getName( (int)$tagId );
 446                 }
 447
 448                 return $tags;
 449         }
 450
 451         /**
 452          * Helper function to generate a fatal status with a 'not-allowed' type error.
 453          *
 454          * @param string $msgOne Message key to use in the case of one tag
 455          * @param string $msgMulti Message key to use in the case of more than one tag
 456          * @param array $tags Restricted tags (passed as $1 into the message, count of
 457          * $tags passed as $2)
 458          * @return Status
 459          * @since 1.25
 460          */
 461         protected static function restrictedTagError( $msgOne, $msgMulti, $tags ) {
 462                 $lang = RequestContext::getMain()->getLanguage();
 463                 $count = count( $tags );
 464                 return Status::newFatal( ( $count > 1 ) ? $msgMulti : $msgOne,
 465                         $lang->commaList( $tags ), $count );
 466         }
 467
 468         /**
 469          * Is it OK to allow the user to apply all the specified tags at the same time
 470          * as they edit/make the change?
 471          *
 472          * Extensions should not use this function, unless directly handling a user
 473          * request to add a tag to a revision or log entry that the user is making.
 474          *
 475          * @param array $tags Tags that you are interested in applying
 476          * @param User|null $user User whose permission you wish to check, or null to
 477          * check for a generic non-blocked user with the relevant rights
 478          * @return Status
 479          * @since 1.25
 480          */
 481         public static function canAddTagsAccompanyingChange( array $tags, User $user = null ) {
 482                 if ( !is_null( $user ) ) {
 483                         if ( !$user->isAllowed( 'applychangetags' ) ) {
 484                                 return Status::newFatal( 'tags-apply-no-permission' );
 485                         } elseif ( $user->isBlocked() ) {
 486                                 return Status::newFatal( 'tags-apply-blocked', $user->getName() );
 487                         }
 488                 }
 489
 490                 // to be applied, a tag has to be explicitly defined
 491                 $allowedTags = self::listExplicitlyDefinedTags();
 492                 Hooks::run( 'ChangeTagsAllowedAdd', [ &$allowedTags, $tags, $user ] );
 493                 $disallowedTags = array_diff( $tags, $allowedTags );
 494                 if ( $disallowedTags ) {
 495                         return self::restrictedTagError( 'tags-apply-not-allowed-one',
 496                                 'tags-apply-not-allowed-multi', $disallowedTags );
 497                 }
 498
 499                 return Status::newGood();
 500         }
 501
 502         /**
 503          * Adds tags to a given change, checking whether it is allowed first, but
 504          * without adding a log entry. Useful for cases where the tag is being added
 505          * along with the action that generated the change (e.g. tagging an edit as
 506          * it is being made).
 507          *
 508          * Extensions should not use this function, unless directly handling a user
 509          * request to add a particular tag. Normally, extensions should call
 510          * ChangeTags::updateTags() instead.
 511          *
 512          * @param array $tags Tags to apply
 513          * @param int|null $rc_id The rc_id of the change to add the tags to
 514          * @param int|null $rev_id The rev_id of the change to add the tags to
 515          * @param int|null $log_id The log_id of the change to add the tags to
 516          * @param string $params Params to put in the ct_params field of table
 517          * 'change_tag' when adding tags
 518          * @param User $user Who to give credit for the action
 519          * @return Status
 520          * @since 1.25
 521          */
 522         public static function addTagsAccompanyingChangeWithChecks(
 523                 array $tags, $rc_id, $rev_id, $log_id, $params, User $user
 524         ) {
 525                 // are we allowed to do this?
 526                 $result = self::canAddTagsAccompanyingChange( $tags, $user );
 527                 if ( !$result->isOK() ) {
 528                         $result->value = null;
 529                         return $result;
 530                 }
 531
 532                 // do it!
 533                 self::addTags( $tags, $rc_id, $rev_id, $log_id, $params );
 534
 535                 return Status::newGood( true );
 536         }
 537
 538         /**
 539          * Is it OK to allow the user to adds and remove the given tags tags to/from a
 540          * change?
 541          *
 542          * Extensions should not use this function, unless directly handling a user
 543          * request to add or remove tags from an existing revision or log entry.
 544          *
 545          * @param array $tagsToAdd Tags that you are interested in adding
 546          * @param array $tagsToRemove Tags that you are interested in removing
 547          * @param User|null $user User whose permission you wish to check, or null to
 548          * check for a generic non-blocked user with the relevant rights
 549          * @return Status
 550          * @since 1.25
 551          */
 552         public static function canUpdateTags( array $tagsToAdd, array $tagsToRemove,
 553                 User $user = null
 554         ) {
 555                 if ( !is_null( $user ) ) {
 556                         if ( !$user->isAllowed( 'changetags' ) ) {
 557                                 return Status::newFatal( 'tags-update-no-permission' );
 558                         } elseif ( $user->isBlocked() ) {
 559                                 return Status::newFatal( 'tags-update-blocked', $user->getName() );
 560                         }
 561                 }
 562
 563                 if ( $tagsToAdd ) {
 564                         // to be added, a tag has to be explicitly defined
 565                         // @todo Allow extensions to define tags that can be applied by users...
 566                         $explicitlyDefinedTags = self::listExplicitlyDefinedTags();
 567                         $diff = array_diff( $tagsToAdd, $explicitlyDefinedTags );
 568                         if ( $diff ) {
 569                                 return self::restrictedTagError( 'tags-update-add-not-allowed-one',
 570                                         'tags-update-add-not-allowed-multi', $diff );
 571                         }
 572                 }
 573
 574                 if ( $tagsToRemove ) {
 575                         // to be removed, a tag must not be defined by an extension, or equivalently it
 576                         // has to be either explicitly defined or not defined at all
 577                         // (assuming no edge case of a tag both explicitly-defined and extension-defined)
 578                         $softwareDefinedTags = self::listSoftwareDefinedTags();
 579                         $intersect = array_intersect( $tagsToRemove, $softwareDefinedTags );
 580                         if ( $intersect ) {
 581                                 return self::restrictedTagError( 'tags-update-remove-not-allowed-one',
 582                                         'tags-update-remove-not-allowed-multi', $intersect );
 583                         }
 584                 }
 585
 586                 return Status::newGood();
 587         }
 588
 589         /**
 590          * Adds and/or removes tags to/from a given change, checking whether it is
 591          * allowed first, and adding a log entry afterwards.
 592          *
 593          * Includes a call to ChangeTags::canUpdateTags(), so your code doesn't need
 594          * to do that. However, it doesn't check whether the *_id parameters are a
 595          * valid combination. That is up to you to enforce. See ApiTag::execute() for
 596          * an example.
 597          *
 598          * Extensions should generally avoid this function. Call
 599          * ChangeTags::updateTags() instead, unless directly handling a user request
 600          * to add or remove tags from an existing revision or log entry.
 601          *
 602          * @param array|null $tagsToAdd If none, pass array() or null
 603          * @param array|null $tagsToRemove If none, pass array() or null
 604          * @param int|null $rc_id The rc_id of the change to add the tags to
 605          * @param int|null $rev_id The rev_id of the change to add the tags to
 606          * @param int|null $log_id The log_id of the change to add the tags to
 607          * @param string $params Params to put in the ct_params field of table
 608          * 'change_tag' when adding tags
 609          * @param string $reason Comment for the log
 610          * @param User $user Who to give credit for the action
 611          * @return Status If successful, the value of this Status object will be an
 612          * object (stdClass) with the following fields:
 613          *  - logId: the ID of the added log entry, or null if no log entry was added
 614          *    (i.e. no operation was performed)
 615          *  - addedTags: an array containing the tags that were actually added
 616          *  - removedTags: an array containing the tags that were actually removed
 617          * @since 1.25
 618          */
 619         public static function updateTagsWithChecks( $tagsToAdd, $tagsToRemove,
 620                 $rc_id, $rev_id, $log_id, $params, $reason, User $user
 621         ) {
 622                 if ( is_null( $tagsToAdd ) ) {
 623                         $tagsToAdd = [];
 624                 }
 625                 if ( is_null( $tagsToRemove ) ) {
 626                         $tagsToRemove = [];
 627                 }
 628                 if ( !$tagsToAdd && !$tagsToRemove ) {
 629                         // no-op, don't bother
 630                         return Status::newGood( (object)[
 631                                 'logId' => null,
 632                                 'addedTags' => [],
 633                                 'removedTags' => [],
 634                         ] );
 635                 }
 636
 637                 // are we allowed to do this?
 638                 $result = self::canUpdateTags( $tagsToAdd, $tagsToRemove, $user );
 639                 if ( !$result->isOK() ) {
 640                         $result->value = null;
 641                         return $result;
 642                 }
 643
 644                 // basic rate limiting
 645                 if ( $user->pingLimiter( 'changetag' ) ) {
 646                         return Status::newFatal( 'actionthrottledtext' );
 647                 }
 648
 649                 // do it!
 650                 list( $tagsAdded, $tagsRemoved, $initialTags ) = self::updateTags( $tagsToAdd,
 651                         $tagsToRemove, $rc_id, $rev_id, $log_id, $params, null, $user );
 652                 if ( !$tagsAdded && !$tagsRemoved ) {
 653                         // no-op, don't log it
 654                         return Status::newGood( (object)[
 655                                 'logId' => null,
 656                                 'addedTags' => [],
 657                                 'removedTags' => [],
 658                         ] );
 659                 }
 660
 661                 // log it
 662                 $logEntry = new ManualLogEntry( 'tag', 'update' );
 663                 $logEntry->setPerformer( $user );
 664                 $logEntry->setComment( $reason );
 665
 666                 // find the appropriate target page
 667                 if ( $rev_id ) {
 668                         $rev = Revision::newFromId( $rev_id );
 669                         if ( $rev ) {
 670                                 $logEntry->setTarget( $rev->getTitle() );
 671                         }
 672                 } elseif ( $log_id ) {
 673                         // This function is from revision deletion logic and has nothing to do with
 674                         // change tags, but it appears to be the only other place in core where we
 675                         // perform logged actions on log items.
 676                         $logEntry->setTarget( RevDelLogList::suggestTarget( null, [ $log_id ] ) );
 677                 }
 678
 679                 if ( !$logEntry->getTarget() ) {
 680                         // target is required, so we have to set something
 681                         $logEntry->setTarget( SpecialPage::getTitleFor( 'Tags' ) );
 682                 }
 683
 684                 $logParams = [
 685                         '4::revid' => $rev_id,
 686                         '5::logid' => $log_id,
 687                         '6:list:tagsAdded' => $tagsAdded,
 688                         '7:number:tagsAddedCount' => count( $tagsAdded ),
 689                         '8:list:tagsRemoved' => $tagsRemoved,
 690                         '9:number:tagsRemovedCount' => count( $tagsRemoved ),
 691                         'initialTags' => $initialTags,
 692                 ];
 693                 $logEntry->setParameters( $logParams );
 694                 $logEntry->setRelations( [ 'Tag' => array_merge( $tagsAdded, $tagsRemoved ) ] );
 695
 696                 $dbw = wfGetDB( DB_MASTER );
 697                 $logId = $logEntry->insert( $dbw );
 698                 // Only send this to UDP, not RC, similar to patrol events
 699                 $logEntry->publish( $logId, 'udp' );
 700
 701                 return Status::newGood( (object)[
 702                         'logId' => $logId,
 703                         'addedTags' => $tagsAdded,
 704                         'removedTags' => $tagsRemoved,
 705                 ] );
 706         }
 707
 708         /**
 709          * Applies all tags-related changes to a query.
 710          * Handles selecting tags, and filtering.
 711          * Needs $tables to be set up properly, so we can figure out which join conditions to use.
 712          *
 713          * WARNING: If $filter_tag contains more than one tag, this function will add DISTINCT,
 714          * which may cause performance problems for your query unless you put the ID field of your
 715          * table at the end of the ORDER BY, and set a GROUP BY equal to the ORDER BY. For example,
 716          * if you had ORDER BY foo_timestamp DESC, you will now need GROUP BY foo_timestamp, foo_id
 717          * ORDER BY foo_timestamp DESC, foo_id DESC.
 718          *
 719          * @param string|array &$tables Table names, see Database::select
 720          * @param string|array &$fields Fields used in query, see Database::select
 721          * @param string|array &$conds Conditions used in query, see Database::select
 722          * @param array &$join_conds Join conditions, see Database::select
 723          * @param string|array &$options Options, see Database::select
 724          * @param string|array $filter_tag Tag(s) to select on
 725          *
 726          * @throws MWException When unable to determine appropriate JOIN condition for tagging
 727          */
 728         public static function modifyDisplayQuery( &$tables, &$fields, &$conds,
 729                 &$join_conds, &$options, $filter_tag = ''
 730         ) {
 731                 global $wgUseTagFilter;
 732
 733                 // Normalize to arrays
 734                 $tables = (array)$tables;
 735                 $fields = (array)$fields;
 736                 $conds = (array)$conds;
 737                 $options = (array)$options;
 738
 739                 $fields['ts_tags'] = self::makeTagSummarySubquery( $tables );
 740
 741                 // Figure out which ID field to use
 742                 if ( in_array( 'recentchanges', $tables ) ) {
 743                         $join_cond = 'ct_rc_id=rc_id';
 744                 } elseif ( in_array( 'logging', $tables ) ) {
 745                         $join_cond = 'ct_log_id=log_id';
 746                 } elseif ( in_array( 'revision', $tables ) ) {
 747                         $join_cond = 'ct_rev_id=rev_id';
 748                 } elseif ( in_array( 'archive', $tables ) ) {
 749                         $join_cond = 'ct_rev_id=ar_rev_id';
 750                 } else {
 751                         throw new MWException( 'Unable to determine appropriate JOIN condition for tagging.' );
 752                 }
 753
 754                 if ( $wgUseTagFilter && $filter_tag ) {
 755                         // Somebody wants to filter on a tag.
 756                         // Add an INNER JOIN on change_tag
 757
 758                         $tables[] = 'change_tag';
 759                         $join_conds['change_tag'] = [ 'JOIN', $join_cond ];
 760                         $filterTagIds = [];
 761                         $changeTagDefStore = MediaWikiServices::getInstance()->getChangeTagDefStore();
 762                         foreach ( (array)$filter_tag as $filterTagName ) {
 763                                 try {
 764                                         $filterTagIds[] = $changeTagDefStore->getId( $filterTagName );
 765                                 } catch ( NameTableAccessException $exception ) {
 766                                         // Return nothing.
 767                                         $conds[] = '0';
 768                                         break;
 769                                 }
 770                         }
 771
 772                         if ( $filterTagIds !== [] ) {
 773                                 $conds['ct_tag_id'] = $filterTagIds;
 774                         }
 775
 776                         if (
 777                                 is_array( $filter_tag ) && count( $filter_tag ) > 1 &&
 778                                 !in_array( 'DISTINCT', $options )
 779                         ) {
 780                                 $options[] = 'DISTINCT';
 781                         }
 782                 }
 783         }
 784
 785         /**
 786          * Make the tag summary subquery based on the given tables and return it.
 787          *
 788          * @param string|array $tables Table names, see Database::select
 789          *
 790          * @return string tag summary subqeury
 791          * @throws MWException When unable to determine appropriate JOIN condition for tagging
 792          */
 793         public static function makeTagSummarySubquery( $tables ) {
 794                 // Normalize to arrays
 795                 $tables = (array)$tables;
 796
 797                 // Figure out which ID field to use
 798                 if ( in_array( 'recentchanges', $tables ) ) {
 799                         $join_cond = 'ct_rc_id=rc_id';
 800                 } elseif ( in_array( 'logging', $tables ) ) {
 801                         $join_cond = 'ct_log_id=log_id';
 802                 } elseif ( in_array( 'revision', $tables ) ) {
 803                         $join_cond = 'ct_rev_id=rev_id';
 804                 } elseif ( in_array( 'archive', $tables ) ) {
 805                         $join_cond = 'ct_rev_id=ar_rev_id';
 806                 } else {
 807                         throw new MWException( 'Unable to determine appropriate JOIN condition for tagging.' );
 808                 }
 809
 810                 $tagTables = [ 'change_tag', 'change_tag_def' ];
 811                 $join_cond_ts_tags = [ 'change_tag_def' => [ 'JOIN', 'ct_tag_id=ctd_id' ] ];
 812                 $field = 'ctd_name';
 813
 814                 return wfGetDB( DB_REPLICA )->buildGroupConcatField(
 815                         ',', $tagTables, $field, $join_cond, $join_cond_ts_tags
 816                 );
 817         }
 818
 819         /**
 820          * Build a text box to select a change tag
 821          *
 822          * @param string $selected Tag to select by default
 823          * @param bool $ooui Use an OOUI TextInputWidget as selector instead of a non-OOUI input field
 824          *        You need to call OutputPage::enableOOUI() yourself.
 825          * @param IContextSource|null $context
 826          * @note Even though it takes null as a valid argument, an IContextSource is preferred
 827          *       in a new code, as the null value can change in the future
 828          * @return array an array of (label, selector)
 829          */
 830         public static function buildTagFilterSelector(
 831                 $selected = '', $ooui = false, IContextSource $context = null
 832         ) {
 833                 if ( !$context ) {
 834                         $context = RequestContext::getMain();
 835                 }
 836
 837                 $config = $context->getConfig();
 838                 if ( !$config->get( 'UseTagFilter' ) || !count( self::listDefinedTags() ) ) {
 839                         return [];
 840                 }
 841
 842                 $data = [
 843                         Html::rawElement(
 844                                 'label',
 845                                 [ 'for' => 'tagfilter' ],
 846                                 $context->msg( 'tag-filter' )->parse()
 847                         )
 848                 ];
 849
 850                 if ( $ooui ) {
 851                         $data[] = new OOUI\TextInputWidget( [
 852                                 'id' => 'tagfilter',
 853                                 'name' => 'tagfilter',
 854                                 'value' => $selected,
 855                                 'classes' => 'mw-tagfilter-input',
 856                         ] );
 857                 } else {
 858                         $data[] = Xml::input(
 859                                 'tagfilter',
 860                                 20,
 861                                 $selected,
 862                                 [ 'class' => 'mw-tagfilter-input mw-ui-input mw-ui-input-inline', 'id' => 'tagfilter' ]
 863                         );
 864                 }
 865
 866                 return $data;
 867         }
 868
 869         /**
 870          * Set ctd_user_defined = 1 in change_tag_def without checking that the tag name is valid.
 871          * Extensions should NOT use this function; they can use the ListDefinedTags
 872          * hook instead.
 873          *
 874          * @param string $tag Tag to create
 875          * @since 1.25
 876          */
 877         public static function defineTag( $tag ) {
 878                 $dbw = wfGetDB( DB_MASTER );
 879                 $tagDef = [
 880                         'ctd_name' => $tag,
 881                         'ctd_user_defined' => 1,
 882                         'ctd_count' => 0
 883                 ];
 884                 $dbw->upsert(
 885                         'change_tag_def',
 886                         $tagDef,
 887                         [ 'ctd_name' ],
 888                         [ 'ctd_user_defined' => 1 ],
 889                         __METHOD__
 890                 );
 891
 892                 // clear the memcache of defined tags
 893                 self::purgeTagCacheAll();
 894         }
 895
 896         /**
 897          * Update ctd_user_defined = 0 field in change_tag_def.
 898          * The tag may remain in use by extensions, and may still show up as 'defined'
 899          * if an extension is setting it from the ListDefinedTags hook.
 900          *
 901          * @param string $tag Tag to remove
 902          * @since 1.25
 903          */
 904         public static function undefineTag( $tag ) {
 905                 $dbw = wfGetDB( DB_MASTER );
 906
 907                 $dbw->update(
 908                         'change_tag_def',
 909                         [ 'ctd_user_defined' => 0 ],
 910                         [ 'ctd_name' => $tag ],
 911                         __METHOD__
 912                 );
 913
 914                 $dbw->delete(
 915                         'change_tag_def',
 916                         [ 'ctd_name' => $tag, 'ctd_count' => 0 ],
 917                         __METHOD__
 918                 );
 919
 920                 // clear the memcache of defined tags
 921                 self::purgeTagCacheAll();
 922         }
 923
 924         /**
 925          * Writes a tag action into the tag management log.
 926          *
 927          * @param string $action
 928          * @param string $tag
 929          * @param string $reason
 930          * @param User $user Who to attribute the action to
 931          * @param int|null $tagCount For deletion only, how many usages the tag had before
 932          * it was deleted.
 933          * @param array $logEntryTags Change tags to apply to the entry
 934          * that will be created in the tag management log
 935          * @return int ID of the inserted log entry
 936          * @since 1.25
 937          */
 938         protected static function logTagManagementAction( $action, $tag, $reason,
 939                 User $user, $tagCount = null, array $logEntryTags = []
 940         ) {
 941                 $dbw = wfGetDB( DB_MASTER );
 942
 943                 $logEntry = new ManualLogEntry( 'managetags', $action );
 944                 $logEntry->setPerformer( $user );
 945                 // target page is not relevant, but it has to be set, so we just put in
 946                 // the title of Special:Tags
 947                 $logEntry->setTarget( Title::newFromText( 'Special:Tags' ) );
 948                 $logEntry->setComment( $reason );
 949
 950                 $params = [ '4::tag' => $tag ];
 951                 if ( !is_null( $tagCount ) ) {
 952                         $params['5:number:count'] = $tagCount;
 953                 }
 954                 $logEntry->setParameters( $params );
 955                 $logEntry->setRelations( [ 'Tag' => $tag ] );
 956                 $logEntry->setTags( $logEntryTags );
 957
 958                 $logId = $logEntry->insert( $dbw );
 959                 $logEntry->publish( $logId );
 960                 return $logId;
 961         }
 962
 963         /**
 964          * Is it OK to allow the user to activate this tag?
 965          *
 966          * @param string $tag Tag that you are interested in activating
 967          * @param User|null $user User whose permission you wish to check, or null if
 968          * you don't care (e.g. maintenance scripts)
 969          * @return Status
 970          * @since 1.25
 971          */
 972         public static function canActivateTag( $tag, User $user = null ) {
 973                 if ( !is_null( $user ) ) {
 974                         if ( !$user->isAllowed( 'managechangetags' ) ) {
 975                                 return Status::newFatal( 'tags-manage-no-permission' );
 976                         } elseif ( $user->isBlocked() ) {
 977                                 return Status::newFatal( 'tags-manage-blocked', $user->getName() );
 978                         }
 979                 }
 980
 981                 // defined tags cannot be activated (a defined tag is either extension-
 982                 // defined, in which case the extension chooses whether or not to active it;
 983                 // or user-defined, in which case it is considered active)
 984                 $definedTags = self::listDefinedTags();
 985                 if ( in_array( $tag, $definedTags ) ) {
 986                         return Status::newFatal( 'tags-activate-not-allowed', $tag );
 987                 }
 988
 989                 // non-existing tags cannot be activated
 990                 $tagUsage = self::tagUsageStatistics();
 991                 if ( !isset( $tagUsage[$tag] ) ) { // we already know the tag is undefined
 992                         return Status::newFatal( 'tags-activate-not-found', $tag );
 993                 }
 994
 995                 return Status::newGood();
 996         }
 997
 998         /**
 999          * Activates a tag, checking whether it is allowed first, and adding a log
1000          * entry afterwards.
1001          *
1002          * Includes a call to ChangeTag::canActivateTag(), so your code doesn't need
1003          * to do that.
1004          *
1005          * @param string $tag
1006          * @param string $reason
1007          * @param User $user Who to give credit for the action
1008          * @param bool $ignoreWarnings Can be used for API interaction, default false
1009          * @param array $logEntryTags Change tags to apply to the entry
1010          * that will be created in the tag management log
1011          * @return Status If successful, the Status contains the ID of the added log
1012          * entry as its value
1013          * @since 1.25
1014          */
1015         public static function activateTagWithChecks( $tag, $reason, User $user,
1016                 $ignoreWarnings = false, array $logEntryTags = []
1017         ) {
1018                 // are we allowed to do this?
1019                 $result = self::canActivateTag( $tag, $user );
1020                 if ( $ignoreWarnings ? !$result->isOK() : !$result->isGood() ) {
1021                         $result->value = null;
1022                         return $result;
1023                 }
1024
1025                 // do it!
1026                 self::defineTag( $tag );
1027
1028                 // log it
1029                 $logId = self::logTagManagementAction( 'activate', $tag, $reason, $user,
1030                         null, $logEntryTags );
1031
1032                 return Status::newGood( $logId );
1033         }
1034
1035         /**
1036          * Is it OK to allow the user to deactivate this tag?
1037          *
1038          * @param string $tag Tag that you are interested in deactivating
1039          * @param User|null $user User whose permission you wish to check, or null if
1040          * you don't care (e.g. maintenance scripts)
1041          * @return Status
1042          * @since 1.25
1043          */
1044         public static function canDeactivateTag( $tag, User $user = null ) {
1045                 if ( !is_null( $user ) ) {
1046                         if ( !$user->isAllowed( 'managechangetags' ) ) {
1047                                 return Status::newFatal( 'tags-manage-no-permission' );
1048                         } elseif ( $user->isBlocked() ) {
1049                                 return Status::newFatal( 'tags-manage-blocked', $user->getName() );
1050                         }
1051                 }
1052
1053                 // only explicitly-defined tags can be deactivated
1054                 $explicitlyDefinedTags = self::listExplicitlyDefinedTags();
1055                 if ( !in_array( $tag, $explicitlyDefinedTags ) ) {
1056                         return Status::newFatal( 'tags-deactivate-not-allowed', $tag );
1057                 }
1058                 return Status::newGood();
1059         }
1060
1061         /**
1062          * Deactivates a tag, checking whether it is allowed first, and adding a log
1063          * entry afterwards.
1064          *
1065          * Includes a call to ChangeTag::canDeactivateTag(), so your code doesn't need
1066          * to do that.
1067          *
1068          * @param string $tag
1069          * @param string $reason
1070          * @param User $user Who to give credit for the action
1071          * @param bool $ignoreWarnings Can be used for API interaction, default false
1072          * @param array $logEntryTags Change tags to apply to the entry
1073          * that will be created in the tag management log
1074          * @return Status If successful, the Status contains the ID of the added log
1075          * entry as its value
1076          * @since 1.25
1077          */
1078         public static function deactivateTagWithChecks( $tag, $reason, User $user,
1079                 $ignoreWarnings = false, array $logEntryTags = []
1080         ) {
1081                 // are we allowed to do this?
1082                 $result = self::canDeactivateTag( $tag, $user );
1083                 if ( $ignoreWarnings ? !$result->isOK() : !$result->isGood() ) {
1084                         $result->value = null;
1085                         return $result;
1086                 }
1087
1088                 // do it!
1089                 self::undefineTag( $tag );
1090
1091                 // log it
1092                 $logId = self::logTagManagementAction( 'deactivate', $tag, $reason, $user,
1093                         null, $logEntryTags );
1094
1095                 return Status::newGood( $logId );
1096         }
1097
1098         /**
1099          * Is the tag name valid?
1100          *
1101          * @param string $tag Tag that you are interested in creating
1102          * @return Status
1103          * @since 1.30
1104          */
1105         public static function isTagNameValid( $tag ) {
1106                 // no empty tags
1107                 if ( $tag === '' ) {
1108                         return Status::newFatal( 'tags-create-no-name' );
1109                 }
1110
1111                 // tags cannot contain commas (used to be used as a delimiter in tag_summary table),
1112                 // pipe (used as a delimiter between multiple tags in
1113                 // SpecialRecentchanges and friends), or slashes (would break tag description messages in
1114                 // MediaWiki namespace)
1115                 if ( strpos( $tag, ',' ) !== false || strpos( $tag, '|' ) !== false
1116                         || strpos( $tag, '/' ) !== false ) {
1117                         return Status::newFatal( 'tags-create-invalid-chars' );
1118                 }
1119
1120                 // could the MediaWiki namespace description messages be created?
1121                 $title = Title::makeTitleSafe( NS_MEDIAWIKI, "Tag-$tag-description" );
1122                 if ( is_null( $title ) ) {
1123                         return Status::newFatal( 'tags-create-invalid-title-chars' );
1124                 }
1125
1126                 return Status::newGood();
1127         }
1128
1129         /**
1130          * Is it OK to allow the user to create this tag?
1131          *
1132          * Extensions should NOT use this function. In most cases, a tag can be
1133          * defined using the ListDefinedTags hook without any checking.
1134          *
1135          * @param string $tag Tag that you are interested in creating
1136          * @param User|null $user User whose permission you wish to check, or null if
1137          * you don't care (e.g. maintenance scripts)
1138          * @return Status
1139          * @since 1.25
1140          */
1141         public static function canCreateTag( $tag, User $user = null ) {
1142                 if ( !is_null( $user ) ) {
1143                         if ( !$user->isAllowed( 'managechangetags' ) ) {
1144                                 return Status::newFatal( 'tags-manage-no-permission' );
1145                         } elseif ( $user->isBlocked() ) {
1146                                 return Status::newFatal( 'tags-manage-blocked', $user->getName() );
1147                         }
1148                 }
1149
1150                 $status = self::isTagNameValid( $tag );
1151                 if ( !$status->isGood() ) {
1152                         return $status;
1153                 }
1154
1155                 // does the tag already exist?
1156                 $tagUsage = self::tagUsageStatistics();
1157                 if ( isset( $tagUsage[$tag] ) || in_array( $tag, self::listDefinedTags() ) ) {
1158                         return Status::newFatal( 'tags-create-already-exists', $tag );
1159                 }
1160
1161                 // check with hooks
1162                 $canCreateResult = Status::newGood();
1163                 Hooks::run( 'ChangeTagCanCreate', [ $tag, $user, &$canCreateResult ] );
1164                 return $canCreateResult;
1165         }
1166
1167         /**
1168          * Creates a tag by adding it to `change_tag_def` table.
1169          *
1170          * Extensions should NOT use this function; they can use the ListDefinedTags
1171          * hook instead.
1172          *
1173          * Includes a call to ChangeTag::canCreateTag(), so your code doesn't need to
1174          * do that.
1175          *
1176          * @param string $tag
1177          * @param string $reason
1178          * @param User $user Who to give credit for the action
1179          * @param bool $ignoreWarnings Can be used for API interaction, default false
1180          * @param array $logEntryTags Change tags to apply to the entry
1181          * that will be created in the tag management log
1182          * @return Status If successful, the Status contains the ID of the added log
1183          * entry as its value
1184          * @since 1.25
1185          */
1186         public static function createTagWithChecks( $tag, $reason, User $user,
1187                 $ignoreWarnings = false, array $logEntryTags = []
1188         ) {
1189                 // are we allowed to do this?
1190                 $result = self::canCreateTag( $tag, $user );
1191                 if ( $ignoreWarnings ? !$result->isOK() : !$result->isGood() ) {
1192                         $result->value = null;
1193                         return $result;
1194                 }
1195
1196                 // do it!
1197                 self::defineTag( $tag );
1198
1199                 // log it
1200                 $logId = self::logTagManagementAction( 'create', $tag, $reason, $user,
1201                         null, $logEntryTags );
1202
1203                 return Status::newGood( $logId );
1204         }
1205
1206         /**
1207          * Permanently removes all traces of a tag from the DB. Good for removing
1208          * misspelt or temporary tags.
1209          *
1210          * This function should be directly called by maintenance scripts only, never
1211          * by user-facing code. See deleteTagWithChecks() for functionality that can
1212          * safely be exposed to users.
1213          *
1214          * @param string $tag Tag to remove
1215          * @return Status The returned status will be good unless a hook changed it
1216          * @since 1.25
1217          */
1218         public static function deleteTagEverywhere( $tag ) {
1219                 $dbw = wfGetDB( DB_MASTER );
1220                 $dbw->startAtomic( __METHOD__ );
1221
1222                 // set ctd_user_defined = 0
1223                 self::undefineTag( $tag );
1224
1225                 // delete from change_tag
1226                 $tagId = MediaWikiServices::getInstance()->getChangeTagDefStore()->getId( $tag );
1227                 $dbw->delete( 'change_tag', [ 'ct_tag_id' => $tagId ], __METHOD__ );
1228                 $dbw->delete( 'change_tag_def', [ 'ctd_name' => $tag ], __METHOD__ );
1229                 $dbw->endAtomic( __METHOD__ );
1230
1231                 // give extensions a chance
1232                 $status = Status::newGood();
1233                 Hooks::run( 'ChangeTagAfterDelete', [ $tag, &$status ] );
1234                 // let's not allow error results, as the actual tag deletion succeeded
1235                 if ( !$status->isOK() ) {
1236                         wfDebug( 'ChangeTagAfterDelete error condition downgraded to warning' );
1237                         $status->setOK( true );
1238                 }
1239
1240                 // clear the memcache of defined tags
1241                 self::purgeTagCacheAll();
1242
1243                 return $status;
1244         }
1245
1246         /**
1247          * Is it OK to allow the user to delete this tag?
1248          *
1249          * @param string $tag Tag that you are interested in deleting
1250          * @param User|null $user User whose permission you wish to check, or null if
1251          * you don't care (e.g. maintenance scripts)
1252          * @return Status
1253          * @since 1.25
1254          */
1255         public static function canDeleteTag( $tag, User $user = null ) {
1256                 $tagUsage = self::tagUsageStatistics();
1257
1258                 if ( !is_null( $user ) ) {
1259                         if ( !$user->isAllowed( 'deletechangetags' ) ) {
1260                                 return Status::newFatal( 'tags-delete-no-permission' );
1261                         } elseif ( $user->isBlocked() ) {
1262                                 return Status::newFatal( 'tags-manage-blocked', $user->getName() );
1263                         }
1264                 }
1265
1266                 if ( !isset( $tagUsage[$tag] ) && !in_array( $tag, self::listDefinedTags() ) ) {
1267                         return Status::newFatal( 'tags-delete-not-found', $tag );
1268                 }
1269
1270                 if ( isset( $tagUsage[$tag] ) && $tagUsage[$tag] > self::MAX_DELETE_USES ) {
1271                         return Status::newFatal( 'tags-delete-too-many-uses', $tag, self::MAX_DELETE_USES );
1272                 }
1273
1274                 $softwareDefined = self::listSoftwareDefinedTags();
1275                 if ( in_array( $tag, $softwareDefined ) ) {
1276                         // extension-defined tags can't be deleted unless the extension
1277                         // specifically allows it
1278                         $status = Status::newFatal( 'tags-delete-not-allowed' );
1279                 } else {
1280                         // user-defined tags are deletable unless otherwise specified
1281                         $status = Status::newGood();
1282                 }
1283
1284                 Hooks::run( 'ChangeTagCanDelete', [ $tag, $user, &$status ] );
1285                 return $status;
1286         }
1287
1288         /**
1289          * Deletes a tag, checking whether it is allowed first, and adding a log entry
1290          * afterwards.
1291          *
1292          * Includes a call to ChangeTag::canDeleteTag(), so your code doesn't need to
1293          * do that.
1294          *
1295          * @param string $tag
1296          * @param string $reason
1297          * @param User $user Who to give credit for the action
1298          * @param bool $ignoreWarnings Can be used for API interaction, default false
1299          * @param array $logEntryTags Change tags to apply to the entry
1300          * that will be created in the tag management log
1301          * @return Status If successful, the Status contains the ID of the added log
1302          * entry as its value
1303          * @since 1.25
1304          */
1305         public static function deleteTagWithChecks( $tag, $reason, User $user,
1306                 $ignoreWarnings = false, array $logEntryTags = []
1307         ) {
1308                 // are we allowed to do this?
1309                 $result = self::canDeleteTag( $tag, $user );
1310                 if ( $ignoreWarnings ? !$result->isOK() : !$result->isGood() ) {
1311                         $result->value = null;
1312                         return $result;
1313                 }
1314
1315                 // store the tag usage statistics
1316                 $tagUsage = self::tagUsageStatistics();
1317                 $hitcount = $tagUsage[$tag] ?? 0;
1318
1319                 // do it!
1320                 $deleteResult = self::deleteTagEverywhere( $tag );
1321                 if ( !$deleteResult->isOK() ) {
1322                         return $deleteResult;
1323                 }
1324
1325                 // log it
1326                 $logId = self::logTagManagementAction( 'delete', $tag, $reason, $user,
1327                         $hitcount, $logEntryTags );
1328
1329                 $deleteResult->value = $logId;
1330                 return $deleteResult;
1331         }
1332
1333         /**
1334          * Lists those tags which core or extensions report as being "active".
1335          *
1336          * @return array
1337          * @since 1.25
1338          */
1339         public static function listSoftwareActivatedTags() {
1340                 // core active tags
1341                 $tags = self::getSoftwareTags();
1342                 if ( !Hooks::isRegistered( 'ChangeTagsListActive' ) ) {
1343                         return $tags;
1344                 }
1345                 $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
1346                 return $cache->getWithSetCallback(
1347                         $cache->makeKey( 'active-tags' ),
1348                         WANObjectCache::TTL_MINUTE * 5,
1349                         function ( $oldValue, &$ttl, array &$setOpts ) use ( $tags ) {
1350                                 $setOpts += Database::getCacheSetOptions( wfGetDB( DB_REPLICA ) );
1351
1352                                 // Ask extensions which tags they consider active
1353                                 Hooks::run( 'ChangeTagsListActive', [ &$tags ] );
1354                                 return $tags;
1355                         },
1356                         [
1357                                 'checkKeys' => [ $cache->makeKey( 'active-tags' ) ],
1358                                 'lockTSE' => WANObjectCache::TTL_MINUTE * 5,
1359                                 'pcTTL' => WANObjectCache::TTL_PROC_LONG
1360                         ]
1361                 );
1362         }
1363
1364         /**
1365          * Basically lists defined tags which count even if they aren't applied to anything.
1366          * It returns a union of the results of listExplicitlyDefinedTags()
1367          *
1368          * @return string[] Array of strings: tags
1369          */
1370         public static function listDefinedTags() {
1371                 $tags1 = self::listExplicitlyDefinedTags();
1372                 $tags2 = self::listSoftwareDefinedTags();
1373                 return array_values( array_unique( array_merge( $tags1, $tags2 ) ) );
1374         }
1375
1376         /**
1377          * Lists tags explicitly defined in the `change_tag_def` table of the database.
1378          *
1379          * Tries memcached first.
1380          *
1381          * @return string[] Array of strings: tags
1382          * @since 1.25
1383          */
1384         public static function listExplicitlyDefinedTags() {
1385                 $fname = __METHOD__;
1386
1387                 $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
1388                 return $cache->getWithSetCallback(
1389                         $cache->makeKey( 'valid-tags-db' ),
1390                         WANObjectCache::TTL_MINUTE * 5,
1391                         function ( $oldValue, &$ttl, array &$setOpts ) use ( $fname ) {
1392                                 $dbr = wfGetDB( DB_REPLICA );
1393
1394                                 $setOpts += Database::getCacheSetOptions( $dbr );
1395
1396                                 $tags = $dbr->selectFieldValues(
1397                                         'change_tag_def',
1398                                         'ctd_name',
1399                                         [ 'ctd_user_defined' => 1 ],
1400                                         $fname
1401                                 );
1402
1403                                 return array_filter( array_unique( $tags ) );
1404                         },
1405                         [
1406                                 'checkKeys' => [ $cache->makeKey( 'valid-tags-db' ) ],
1407                                 'lockTSE' => WANObjectCache::TTL_MINUTE * 5,
1408                                 'pcTTL' => WANObjectCache::TTL_PROC_LONG
1409                         ]
1410                 );
1411         }
1412
1413         /**
1414          * Lists tags defined by core or extensions using the ListDefinedTags hook.
1415          * Extensions need only define those tags they deem to be in active use.
1416          *
1417          * Tries memcached first.
1418          *
1419          * @return string[] Array of strings: tags
1420          * @since 1.25
1421          */
1422         public static function listSoftwareDefinedTags() {
1423                 // core defined tags
1424                 $tags = self::getSoftwareTags( true );
1425                 if ( !Hooks::isRegistered( 'ListDefinedTags' ) ) {
1426                         return $tags;
1427                 }
1428                 $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
1429                 return $cache->getWithSetCallback(
1430                         $cache->makeKey( 'valid-tags-hook' ),
1431                         WANObjectCache::TTL_MINUTE * 5,
1432                         function ( $oldValue, &$ttl, array &$setOpts ) use ( $tags ) {
1433                                 $setOpts += Database::getCacheSetOptions( wfGetDB( DB_REPLICA ) );
1434
1435                                 Hooks::run( 'ListDefinedTags', [ &$tags ] );
1436                                 return array_filter( array_unique( $tags ) );
1437                         },
1438                         [
1439                                 'checkKeys' => [ $cache->makeKey( 'valid-tags-hook' ) ],
1440                                 'lockTSE' => WANObjectCache::TTL_MINUTE * 5,
1441                                 'pcTTL' => WANObjectCache::TTL_PROC_LONG
1442                         ]
1443                 );
1444         }
1445
1446         /**
1447          * Invalidates the short-term cache of defined tags used by the
1448          * list*DefinedTags functions, as well as the tag statistics cache.
1449          * @since 1.25
1450          */
1451         public static function purgeTagCacheAll() {
1452                 $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
1453
1454                 $cache->touchCheckKey( $cache->makeKey( 'active-tags' ) );
1455                 $cache->touchCheckKey( $cache->makeKey( 'valid-tags-db' ) );
1456                 $cache->touchCheckKey( $cache->makeKey( 'valid-tags-hook' ) );
1457
1458                 MediaWikiServices::getInstance()->getChangeTagDefStore()->reloadMap();
1459         }
1460
1461         /**
1462          * Invalidates the tag statistics cache only.
1463          * @since 1.25
1464          * @deprecated since 1.33 the cache this purges no longer exists
1465          */
1466         public static function purgeTagUsageCache() {
1467                 wfDeprecated( __METHOD__, '1.33' );
1468         }
1469
1470         /**
1471          * Returns a map of any tags used on the wiki to number of edits
1472          * tagged with them, ordered descending by the hitcount.
1473          * This does not include tags defined somewhere that have never been applied.
1474          * @return array Array of string => int
1475          */
1476         public static function tagUsageStatistics() {
1477                 $dbr = wfGetDB( DB_REPLICA );
1478                 $res = $dbr->select(
1479                         'change_tag_def',
1480                         [ 'ctd_name', 'ctd_count' ],
1481                         [],
1482                         __METHOD__,
1483                         [ 'ORDER BY' => 'ctd_count DESC' ]
1484                 );
1485
1486                 $out = [];
1487                 foreach ( $res as $row ) {
1488                         $out[$row->ctd_name] = $row->ctd_count;
1489                 }
1490
1491                 return $out;
1492         }
1493
1494         /**
1495          * Indicate whether change tag editing UI is relevant
1496          *
1497          * Returns true if the user has the necessary right and there are any
1498          * editable tags defined.
1499          *
1500          * This intentionally doesn't check "any addable || any deletable", because
1501          * it seems like it would be more confusing than useful if the checkboxes
1502          * suddenly showed up because some abuse filter stopped defining a tag and
1503          * then suddenly disappeared when someone deleted all uses of that tag.
1504          *
1505          * @param User $user
1506          * @return bool
1507          */
1508         public static function showTagEditingUI( User $user ) {
1509                 return $user->isAllowed( 'changetags' ) && (bool)self::listExplicitlyDefinedTags();
1510         }
1511 }