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