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 Wikimedia\Rdbms\Database;
  26
  27 class ChangeTags {
  28         /**
  29          * Can't delete tags with more than this many uses. Similar in intent to
  30          * the bigdelete user right
  31          * @todo Use the job queue for tag deletion to avoid this restriction
  32          */
  33         const MAX_DELETE_USES = 5000;
  34
  35         private static $definedSoftwareTags = [
  36                 'mw-contentmodelchange',
  37                 'mw-new-redirect',
  38                 'mw-removed-redirect',
  39                 'mw-changed-redirect-target',
  40                 'mw-blank',
  41                 'mw-replace',
  42                 'mw-rollback',
  43                 'mw-undo',
  44         ];
  45
  46         /**
  47          * Loads defined core tags, checks for invalid types (if not array),
  48          * and filters for supported and enabled (if $all is false) tags only.
  49          *
  50          * @param bool $all If true, return all valid defined tags. Otherwise, return only enabled ones.
  51          * @return array Array of all defined/enabled tags.
  52          */
  53         public static function getSoftwareTags( $all = false ) {
  54                 global $wgSoftwareTags;
  55                 $softwareTags = [];
  56
  57                 if ( !is_array( $wgSoftwareTags ) ) {
  58                         wfWarn( 'wgSoftwareTags should be associative array of enabled tags.
  59                         Please refer to documentation for the list of tags you can enable' );
  60                         return $softwareTags;
  61                 }
  62
  63                 $availableSoftwareTags = !$all ?
  64                         array_keys( array_filter( $wgSoftwareTags ) ) :
  65                         array_keys( $wgSoftwareTags );
  66
  67                 $softwareTags = array_intersect(
  68                         $availableSoftwareTags,
  69                         self::$definedSoftwareTags
  70                 );
  71
  72                 return $softwareTags;
  73         }
  74
  75         /**
  76          * Creates HTML for the given tags
  77          *
  78          * @param string $tags Comma-separated list of tags
  79          * @param string $page A label for the type of action which is being displayed,
  80          *   for example: 'history', 'contributions' or 'newpages'
  81          * @param IContextSource|null $context
  82          * @note Even though it takes null as a valid argument, an IContextSource is preferred
  83          *       in a new code, as the null value is subject to change in the future
  84          * @return array Array with two items: (html, classes)
  85          *   - html: String: HTML for displaying the tags (empty string when param $tags is empty)
  86          *   - classes: Array of strings: CSS classes used in the generated html, one class for each tag
  87          */
  88         public static function formatSummaryRow( $tags, $page, IContextSource $context = null ) {
  89                 if ( !$tags ) {
  90                         return [ '', [] ];
  91                 }
  92                 if ( !$context ) {
  93                         $context = RequestContext::getMain();
  94                 }
  95
  96                 $classes = [];
  97
  98                 $tags = explode( ',', $tags );
  99                 $displayTags = [];
 100                 foreach ( $tags as $tag ) {
 101                         if ( !$tag ) {
 102                                 continue;
 103                         }
 104                         $description = self::tagDescription( $tag, $context );
 105                         if ( $description === false ) {
 106                                 continue;
 107                         }
 108                         $displayTags[] = Xml::tags(
 109                                 'span',
 110                                 [ 'class' => 'mw-tag-marker ' .
 111                                                                 Sanitizer::escapeClass( "mw-tag-marker-$tag" ) ],
 112                                 $description
 113                         );
 114                         $classes[] = Sanitizer::escapeClass( "mw-tag-$tag" );
 115                 }
 116
 117                 if ( !$displayTags ) {
 118                         return [ '', [] ];
 119                 }
 120
 121                 $markers = $context->msg( 'tag-list-wrapper' )
 122                         ->numParams( count( $displayTags ) )
 123                         ->rawParams( $context->getLanguage()->commaList( $displayTags ) )
 124                         ->parse();
 125                 $markers = Xml::tags( 'span', [ 'class' => 'mw-tag-markers' ], $markers );
 126
 127                 return [ $markers, $classes ];
 128         }
 129
 130         /**
 131          * Get a short description for a tag.
 132          *
 133          * Checks if message key "mediawiki:tag-$tag" exists. If it does not,
 134          * returns the HTML-escaped tag name. Uses the message if the message
 135          * exists, provided it is not disabled. If the message is disabled,
 136          * we consider the tag hidden, and return false.
 137          *
 138          * @param string $tag
 139          * @param IContextSource $context
 140          * @return string|bool Tag description or false if tag is to be hidden.
 141          * @since 1.25 Returns false if tag is to be hidden.
 142          */
 143         public static function tagDescription( $tag, IContextSource $context ) {
 144                 $msg = $context->msg( "tag-$tag" );
 145                 if ( !$msg->exists() ) {
 146                         // No such message, so return the HTML-escaped tag name.
 147                         return htmlspecialchars( $tag );
 148                 }
 149                 if ( $msg->isDisabled() ) {
 150                         // The message exists but is disabled, hide the tag.
 151                         return false;
 152                 }
 153
 154                 // Message exists and isn't disabled, use it.
 155                 return $msg->parse();
 156         }
 157
 158         /**
 159          * Get the message object for the tag's long description.
 160          *
 161          * Checks if message key "mediawiki:tag-$tag-description" exists. If it does not,
 162          * or if message is disabled, returns false. Otherwise, returns the message object
 163          * for the long description.
 164          *
 165          * @param string $tag
 166          * @param IContextSource $context
 167          * @return Message|bool Message object of the tag long description or false if
 168          *  there is no description.
 169          */
 170         public static function tagLongDescriptionMessage( $tag, IContextSource $context ) {
 171                 $msg = $context->msg( "tag-$tag-description" );
 172                 if ( !$msg->exists() ) {
 173                         return false;
 174                 }
 175                 if ( $msg->isDisabled() ) {
 176                         // The message exists but is disabled, hide the description.
 177                         return false;
 178                 }
 179
 180                 // Message exists and isn't disabled, use it.
 181                 return $msg;
 182         }
 183
 184         /**
 185          * Add tags to a change given its rc_id, rev_id and/or log_id
 186          *
 187          * @param string|string[] $tags Tags to add to the change
 188          * @param int|null $rc_id The rc_id of the change to add the tags to
 189          * @param int|null $rev_id The rev_id of the change to add the tags to
 190          * @param int|null $log_id The log_id of the change to add the tags to
 191          * @param string $params Params to put in the ct_params field of table 'change_tag'
 192          * @param RecentChange|null $rc Recent change, in case the tagging accompanies the action
 193          * (this should normally be the case)
 194          *
 195          * @throws MWException
 196          * @return bool False if no changes are made, otherwise true
 197          */
 198         public static function addTags( $tags, $rc_id = null, $rev_id = null,
 199                 $log_id = null, $params = null, RecentChange $rc = null
 200         ) {
 201                 $result = self::updateTags( $tags, null, $rc_id, $rev_id, $log_id, $params, $rc );
 202                 return (bool)$result[0];
 203         }
 204
 205         /**
 206          * Add and remove tags to/from a change given its rc_id, rev_id and/or log_id,
 207          * without verifying that the tags exist or are valid. If a tag is present in
 208          * both $tagsToAdd and $tagsToRemove, it will be removed.
 209          *
 210          * This function should only be used by extensions to manipulate tags they
 211          * have registered using the ListDefinedTags hook. When dealing with user
 212          * input, call updateTagsWithChecks() instead.
 213          *
 214          * @param string|array|null $tagsToAdd Tags to add to the change
 215          * @param string|array|null $tagsToRemove Tags to remove from the change
 216          * @param int|null &$rc_id The rc_id of the change to add the tags to.
 217          * Pass a variable whose value is null if the rc_id is not relevant or unknown.
 218          * @param int|null &$rev_id The rev_id of the change to add the tags to.
 219          * Pass a variable whose value is null if the rev_id is not relevant or unknown.
 220          * @param int|null &$log_id The log_id of the change to add the tags to.
 221          * Pass a variable whose value is null if the log_id is not relevant or unknown.
 222          * @param string $params Params to put in the ct_params field of table
 223          * 'change_tag' when adding tags
 224          * @param RecentChange|null $rc Recent change being tagged, in case the tagging accompanies
 225          * the action
 226          * @param User|null $user Tagging user, in case the tagging is subsequent to the tagged action
 227          *
 228          * @throws MWException When $rc_id, $rev_id and $log_id are all null
 229          * @return array Index 0 is an array of tags actually added, index 1 is an
 230          * array of tags actually removed, index 2 is an array of tags present on the
 231          * revision or log entry before any changes were made
 232          *
 233          * @since 1.25
 234          */
 235         public static function updateTags( $tagsToAdd, $tagsToRemove, &$rc_id = null,
 236                 &$rev_id = null, &$log_id = null, $params = null, RecentChange $rc = null,
 237                 User $user = null
 238         ) {
 239                 $tagsToAdd = array_filter( (array)$tagsToAdd ); // Make sure we're submitting all tags...
 240                 $tagsToRemove = array_filter( (array)$tagsToRemove );
 241
 242                 if ( !$rc_id && !$rev_id && !$log_id ) {
 243                         throw new MWException( 'At least one of: RCID, revision ID, and log ID MUST be ' .
 244                                 'specified when adding or removing a tag from a change!' );
 245                 }
 246
 247                 $dbw = wfGetDB( DB_MASTER );
 248
 249                 // Might as well look for rcids and so on.
 250                 if ( !$rc_id ) {
 251                         // Info might be out of date, somewhat fractionally, on replica DB.
 252                         // LogEntry/LogPage and WikiPage match rev/log/rc timestamps,
 253                         // so use that relation to avoid full table scans.
 254                         if ( $log_id ) {
 255                                 $rc_id = $dbw->selectField(
 256                                         [ 'logging', 'recentchanges' ],
 257                                         'rc_id',
 258                                         [
 259                                                 'log_id' => $log_id,
 260                                                 'rc_timestamp = log_timestamp',
 261                                                 'rc_logid = log_id'
 262                                         ],
 263                                         __METHOD__
 264                                 );
 265                         } elseif ( $rev_id ) {
 266                                 $rc_id = $dbw->selectField(
 267                                         [ 'revision', 'recentchanges' ],
 268                                         'rc_id',
 269                                         [
 270                                                 'rev_id' => $rev_id,
 271                                                 'rc_timestamp = rev_timestamp',
 272                                                 'rc_this_oldid = rev_id'
 273                                         ],
 274                                         __METHOD__
 275                                 );
 276                         }
 277                 } elseif ( !$log_id && !$rev_id ) {
 278                         // Info might be out of date, somewhat fractionally, on replica DB.
 279                         $log_id = $dbw->selectField(
 280                                 'recentchanges',
 281                                 'rc_logid',
 282                                 [ 'rc_id' => $rc_id ],
 283                                 __METHOD__
 284                         );
 285                         $rev_id = $dbw->selectField(
 286                                 'recentchanges',
 287                                 'rc_this_oldid',
 288                                 [ 'rc_id' => $rc_id ],
 289                                 __METHOD__
 290                         );
 291                 }
 292
 293                 if ( $log_id && !$rev_id ) {
 294                         $rev_id = $dbw->selectField(
 295                                 'log_search',
 296                                 'ls_value',
 297                                 [ 'ls_field' => 'associated_rev_id', 'ls_log_id' => $log_id ],
 298                                 __METHOD__
 299                         );
 300                 } elseif ( !$log_id && $rev_id ) {
 301                         $log_id = $dbw->selectField(
 302                                 'log_search',
 303                                 'ls_log_id',
 304                                 [ 'ls_field' => 'associated_rev_id', 'ls_value' => $rev_id ],
 305                                 __METHOD__
 306                         );
 307                 }
 308
 309                 // update the tag_summary row
 310                 $prevTags = [];
 311                 if ( !self::updateTagSummaryRow( $tagsToAdd, $tagsToRemove, $rc_id, $rev_id,
 312                         $log_id, $prevTags )
 313                 ) {
 314                         // nothing to do
 315                         return [ [], [], $prevTags ];
 316                 }
 317
 318                 // insert a row into change_tag for each new tag
 319                 if ( count( $tagsToAdd ) ) {
 320                         $tagsRows = [];
 321                         foreach ( $tagsToAdd as $tag ) {
 322                                 // Filter so we don't insert NULLs as zero accidentally.
 323                                 // Keep in mind that $rc_id === null means "I don't care/know about the
 324                                 // rc_id, just delete $tag on this revision/log entry". It doesn't
 325                                 // mean "only delete tags on this revision/log WHERE rc_id IS NULL".
 326                                 $tagsRows[] = array_filter(
 327                                         [
 328                                                 'ct_tag' => $tag,
 329                                                 'ct_rc_id' => $rc_id,
 330                                                 'ct_log_id' => $log_id,
 331                                                 'ct_rev_id' => $rev_id,
 332                                                 'ct_params' => $params
 333                                         ]
 334                                 );
 335                         }
 336
 337                         $dbw->insert( 'change_tag', $tagsRows, __METHOD__, [ 'IGNORE' ] );
 338                 }
 339
 340                 // delete from change_tag
 341                 if ( count( $tagsToRemove ) ) {
 342                         foreach ( $tagsToRemove as $tag ) {
 343                                 $conds = array_filter(
 344                                         [
 345                                                 'ct_tag' => $tag,
 346                                                 'ct_rc_id' => $rc_id,
 347                                                 'ct_log_id' => $log_id,
 348                                                 'ct_rev_id' => $rev_id
 349                                         ]
 350                                 );
 351                                 $dbw->delete( 'change_tag', $conds, __METHOD__ );
 352                         }
 353                 }
 354
 355                 self::purgeTagUsageCache();
 356
 357                 Hooks::run( 'ChangeTagsAfterUpdateTags', [ $tagsToAdd, $tagsToRemove, $prevTags,
 358                         $rc_id, $rev_id, $log_id, $params, $rc, $user ] );
 359
 360                 return [ $tagsToAdd, $tagsToRemove, $prevTags ];
 361         }
 362
 363         /**
 364          * Adds or removes a given set of tags to/from the relevant row of the
 365          * tag_summary table. Modifies the tagsToAdd and tagsToRemove arrays to
 366          * reflect the tags that were actually added and/or removed.
 367          *
 368          * @param array &$tagsToAdd
 369          * @param array &$tagsToRemove If a tag is present in both $tagsToAdd and
 370          * $tagsToRemove, it will be removed
 371          * @param int|null $rc_id Null if not known or not applicable
 372          * @param int|null $rev_id Null if not known or not applicable
 373          * @param int|null $log_id Null if not known or not applicable
 374          * @param array &$prevTags Optionally outputs a list of the tags that were
 375          * in the tag_summary row to begin with
 376          * @return bool True if any modifications were made, otherwise false
 377          * @since 1.25
 378          */
 379         protected static function updateTagSummaryRow( &$tagsToAdd, &$tagsToRemove,
 380                 $rc_id, $rev_id, $log_id, &$prevTags = []
 381         ) {
 382                 $dbw = wfGetDB( DB_MASTER );
 383
 384                 $tsConds = array_filter( [
 385                         'ts_rc_id' => $rc_id,
 386                         'ts_rev_id' => $rev_id,
 387                         'ts_log_id' => $log_id
 388                 ] );
 389
 390                 // Can't both add and remove a tag at the same time...
 391                 $tagsToAdd = array_diff( $tagsToAdd, $tagsToRemove );
 392
 393                 // Update the summary row.
 394                 // $prevTags can be out of date on replica DBs, especially when addTags is called consecutively,
 395                 // causing loss of tags added recently in tag_summary table.
 396                 $prevTags = $dbw->selectField( 'tag_summary', 'ts_tags', $tsConds, __METHOD__ );
 397                 $prevTags = $prevTags ? $prevTags : '';
 398                 $prevTags = array_filter( explode( ',', $prevTags ) );
 399
 400                 // add tags
 401                 $tagsToAdd = array_values( array_diff( $tagsToAdd, $prevTags ) );
 402                 $newTags = array_unique( array_merge( $prevTags, $tagsToAdd ) );
 403
 404                 // remove tags
 405                 $tagsToRemove = array_values( array_intersect( $tagsToRemove, $newTags ) );
 406                 $newTags = array_values( array_diff( $newTags, $tagsToRemove ) );
 407
 408                 sort( $prevTags );
 409                 sort( $newTags );
 410                 if ( $prevTags == $newTags ) {
 411                         return false;
 412                 }
 413
 414                 if ( !$newTags ) {
 415                         // No tags left, so delete the row altogether
 416                         $dbw->delete( 'tag_summary', $tsConds, __METHOD__ );
 417                 } else {
 418                         // Specify the non-DEFAULT value columns in the INSERT/REPLACE clause
 419                         $row = array_filter( [ 'ts_tags' => implode( ',', $newTags ) ] + $tsConds );
 420                         // Check the unique keys for conflicts, ignoring any NULL *_id values
 421                         $uniqueKeys = [];
 422                         foreach ( [ 'ts_rev_id', 'ts_rc_id', 'ts_log_id' ] as $uniqueColumn ) {
 423                                 if ( isset( $row[$uniqueColumn] ) ) {
 424                                         $uniqueKeys[] = [ $uniqueColumn ];
 425                                 }
 426                         }
 427
 428                         $dbw->replace( 'tag_summary', $uniqueKeys, $row, __METHOD__ );
 429                 }
 430
 431                 return true;
 432         }
 433
 434         /**
 435          * Helper function to generate a fatal status with a 'not-allowed' type error.
 436          *
 437          * @param string $msgOne Message key to use in the case of one tag
 438          * @param string $msgMulti Message key to use in the case of more than one tag
 439          * @param array $tags Restricted tags (passed as $1 into the message, count of
 440          * $tags passed as $2)
 441          * @return Status
 442          * @since 1.25
 443          */
 444         protected static function restrictedTagError( $msgOne, $msgMulti, $tags ) {
 445                 $lang = RequestContext::getMain()->getLanguage();
 446                 $count = count( $tags );
 447                 return Status::newFatal( ( $count > 1 ) ? $msgMulti : $msgOne,
 448                         $lang->commaList( $tags ), $count );
 449         }
 450
 451         /**
 452          * Is it OK to allow the user to apply all the specified tags at the same time
 453          * as they edit/make the change?
 454          *
 455          * @param array $tags Tags that you are interested in applying
 456          * @param User|null $user User whose permission you wish to check, or null if
 457          * you don't care (e.g. maintenance scripts)
 458          * @return Status
 459          * @since 1.25
 460          */
 461         public static function canAddTagsAccompanyingChange( array $tags, User $user = null ) {
 462                 if ( !is_null( $user ) ) {
 463                         if ( !$user->isAllowed( 'applychangetags' ) ) {
 464                                 return Status::newFatal( 'tags-apply-no-permission' );
 465                         } elseif ( $user->isBlocked() ) {
 466                                 return Status::newFatal( 'tags-apply-blocked', $user->getName() );
 467                         }
 468                 }
 469
 470                 // to be applied, a tag has to be explicitly defined
 471                 $allowedTags = self::listExplicitlyDefinedTags();
 472                 Hooks::run( 'ChangeTagsAllowedAdd', [ &$allowedTags, $tags, $user ] );
 473                 $disallowedTags = array_diff( $tags, $allowedTags );
 474                 if ( $disallowedTags ) {
 475                         return self::restrictedTagError( 'tags-apply-not-allowed-one',
 476                                 'tags-apply-not-allowed-multi', $disallowedTags );
 477                 }
 478
 479                 return Status::newGood();
 480         }
 481
 482         /**
 483          * Adds tags to a given change, checking whether it is allowed first, but
 484          * without adding a log entry. Useful for cases where the tag is being added
 485          * along with the action that generated the change (e.g. tagging an edit as
 486          * it is being made).
 487          *
 488          * Extensions should not use this function, unless directly handling a user
 489          * request to add a particular tag. Normally, extensions should call
 490          * ChangeTags::updateTags() instead.
 491          *
 492          * @param array $tags Tags to apply
 493          * @param int|null $rc_id The rc_id of the change to add the tags to
 494          * @param int|null $rev_id The rev_id of the change to add the tags to
 495          * @param int|null $log_id The log_id of the change to add the tags to
 496          * @param string $params Params to put in the ct_params field of table
 497          * 'change_tag' when adding tags
 498          * @param User $user Who to give credit for the action
 499          * @return Status
 500          * @since 1.25
 501          */
 502         public static function addTagsAccompanyingChangeWithChecks(
 503                 array $tags, $rc_id, $rev_id, $log_id, $params, User $user
 504         ) {
 505                 // are we allowed to do this?
 506                 $result = self::canAddTagsAccompanyingChange( $tags, $user );
 507                 if ( !$result->isOK() ) {
 508                         $result->value = null;
 509                         return $result;
 510                 }
 511
 512                 // do it!
 513                 self::addTags( $tags, $rc_id, $rev_id, $log_id, $params );
 514
 515                 return Status::newGood( true );
 516         }
 517
 518         /**
 519          * Is it OK to allow the user to adds and remove the given tags tags to/from a
 520          * change?
 521          *
 522          * @param array $tagsToAdd Tags that you are interested in adding
 523          * @param array $tagsToRemove Tags that you are interested in removing
 524          * @param User|null $user User whose permission you wish to check, or null if
 525          * you don't care (e.g. maintenance scripts)
 526          * @return Status
 527          * @since 1.25
 528          */
 529         public static function canUpdateTags( array $tagsToAdd, array $tagsToRemove,
 530                 User $user = null
 531         ) {
 532                 if ( !is_null( $user ) ) {
 533                         if ( !$user->isAllowed( 'changetags' ) ) {
 534                                 return Status::newFatal( 'tags-update-no-permission' );
 535                         } elseif ( $user->isBlocked() ) {
 536                                 return Status::newFatal( 'tags-update-blocked', $user->getName() );
 537                         }
 538                 }
 539
 540                 if ( $tagsToAdd ) {
 541                         // to be added, a tag has to be explicitly defined
 542                         // @todo Allow extensions to define tags that can be applied by users...
 543                         $explicitlyDefinedTags = self::listExplicitlyDefinedTags();
 544                         $diff = array_diff( $tagsToAdd, $explicitlyDefinedTags );
 545                         if ( $diff ) {
 546                                 return self::restrictedTagError( 'tags-update-add-not-allowed-one',
 547                                         'tags-update-add-not-allowed-multi', $diff );
 548                         }
 549                 }
 550
 551                 if ( $tagsToRemove ) {
 552                         // to be removed, a tag must not be defined by an extension, or equivalently it
 553                         // has to be either explicitly defined or not defined at all
 554                         // (assuming no edge case of a tag both explicitly-defined and extension-defined)
 555                         $softwareDefinedTags = self::listSoftwareDefinedTags();
 556                         $intersect = array_intersect( $tagsToRemove, $softwareDefinedTags );
 557                         if ( $intersect ) {
 558                                 return self::restrictedTagError( 'tags-update-remove-not-allowed-one',
 559                                         'tags-update-remove-not-allowed-multi', $intersect );
 560                         }
 561                 }
 562
 563                 return Status::newGood();
 564         }
 565
 566         /**
 567          * Adds and/or removes tags to/from a given change, checking whether it is
 568          * allowed first, and adding a log entry afterwards.
 569          *
 570          * Includes a call to ChangeTag::canUpdateTags(), so your code doesn't need
 571          * to do that. However, it doesn't check whether the *_id parameters are a
 572          * valid combination. That is up to you to enforce. See ApiTag::execute() for
 573          * an example.
 574          *
 575          * @param array|null $tagsToAdd If none, pass array() or null
 576          * @param array|null $tagsToRemove If none, pass array() or null
 577          * @param int|null $rc_id The rc_id of the change to add the tags to
 578          * @param int|null $rev_id The rev_id of the change to add the tags to
 579          * @param int|null $log_id The log_id of the change to add the tags to
 580          * @param string $params Params to put in the ct_params field of table
 581          * 'change_tag' when adding tags
 582          * @param string $reason Comment for the log
 583          * @param User $user Who to give credit for the action
 584          * @return Status If successful, the value of this Status object will be an
 585          * object (stdClass) with the following fields:
 586          *  - logId: the ID of the added log entry, or null if no log entry was added
 587          *    (i.e. no operation was performed)
 588          *  - addedTags: an array containing the tags that were actually added
 589          *  - removedTags: an array containing the tags that were actually removed
 590          * @since 1.25
 591          */
 592         public static function updateTagsWithChecks( $tagsToAdd, $tagsToRemove,
 593                 $rc_id, $rev_id, $log_id, $params, $reason, User $user
 594         ) {
 595                 if ( is_null( $tagsToAdd ) ) {
 596                         $tagsToAdd = [];
 597                 }
 598                 if ( is_null( $tagsToRemove ) ) {
 599                         $tagsToRemove = [];
 600                 }
 601                 if ( !$tagsToAdd && !$tagsToRemove ) {
 602                         // no-op, don't bother
 603                         return Status::newGood( (object)[
 604                                 'logId' => null,
 605                                 'addedTags' => [],
 606                                 'removedTags' => [],
 607                         ] );
 608                 }
 609
 610                 // are we allowed to do this?
 611                 $result = self::canUpdateTags( $tagsToAdd, $tagsToRemove, $user );
 612                 if ( !$result->isOK() ) {
 613                         $result->value = null;
 614                         return $result;
 615                 }
 616
 617                 // basic rate limiting
 618                 if ( $user->pingLimiter( 'changetag' ) ) {
 619                         return Status::newFatal( 'actionthrottledtext' );
 620                 }
 621
 622                 // do it!
 623                 list( $tagsAdded, $tagsRemoved, $initialTags ) = self::updateTags( $tagsToAdd,
 624                         $tagsToRemove, $rc_id, $rev_id, $log_id, $params, null, $user );
 625                 if ( !$tagsAdded && !$tagsRemoved ) {
 626                         // no-op, don't log it
 627                         return Status::newGood( (object)[
 628                                 'logId' => null,
 629                                 'addedTags' => [],
 630                                 'removedTags' => [],
 631                         ] );
 632                 }
 633
 634                 // log it
 635                 $logEntry = new ManualLogEntry( 'tag', 'update' );
 636                 $logEntry->setPerformer( $user );
 637                 $logEntry->setComment( $reason );
 638
 639                 // find the appropriate target page
 640                 if ( $rev_id ) {
 641                         $rev = Revision::newFromId( $rev_id );
 642                         if ( $rev ) {
 643                                 $logEntry->setTarget( $rev->getTitle() );
 644                         }
 645                 } elseif ( $log_id ) {
 646                         // This function is from revision deletion logic and has nothing to do with
 647                         // change tags, but it appears to be the only other place in core where we
 648                         // perform logged actions on log items.
 649                         $logEntry->setTarget( RevDelLogList::suggestTarget( null, [ $log_id ] ) );
 650                 }
 651
 652                 if ( !$logEntry->getTarget() ) {
 653                         // target is required, so we have to set something
 654                         $logEntry->setTarget( SpecialPage::getTitleFor( 'Tags' ) );
 655                 }
 656
 657                 $logParams = [
 658                         '4::revid' => $rev_id,
 659                         '5::logid' => $log_id,
 660                         '6:list:tagsAdded' => $tagsAdded,
 661                         '7:number:tagsAddedCount' => count( $tagsAdded ),
 662                         '8:list:tagsRemoved' => $tagsRemoved,
 663                         '9:number:tagsRemovedCount' => count( $tagsRemoved ),
 664                         'initialTags' => $initialTags,
 665                 ];
 666                 $logEntry->setParameters( $logParams );
 667                 $logEntry->setRelations( [ 'Tag' => array_merge( $tagsAdded, $tagsRemoved ) ] );
 668
 669                 $dbw = wfGetDB( DB_MASTER );
 670                 $logId = $logEntry->insert( $dbw );
 671                 // Only send this to UDP, not RC, similar to patrol events
 672                 $logEntry->publish( $logId, 'udp' );
 673
 674                 return Status::newGood( (object)[
 675                         'logId' => $logId,
 676                         'addedTags' => $tagsAdded,
 677                         'removedTags' => $tagsRemoved,
 678                 ] );
 679         }
 680
 681         /**
 682          * Applies all tags-related changes to a query.
 683          * Handles selecting tags, and filtering.
 684          * Needs $tables to be set up properly, so we can figure out which join conditions to use.
 685          *
 686          * WARNING: If $filter_tag contains more than one tag, this function will add DISTINCT,
 687          * which may cause performance problems for your query unless you put the ID field of your
 688          * table at the end of the ORDER BY, and set a GROUP BY equal to the ORDER BY. For example,
 689          * if you had ORDER BY foo_timestamp DESC, you will now need GROUP BY foo_timestamp, foo_id
 690          * ORDER BY foo_timestamp DESC, foo_id DESC.
 691          *
 692          * @param string|array &$tables Table names, see Database::select
 693          * @param string|array &$fields Fields used in query, see Database::select
 694          * @param string|array &$conds Conditions used in query, see Database::select
 695          * @param array &$join_conds Join conditions, see Database::select
 696          * @param string|array &$options Options, see Database::select
 697          * @param string|array $filter_tag Tag(s) to select on
 698          *
 699          * @throws MWException When unable to determine appropriate JOIN condition for tagging
 700          */
 701         public static function modifyDisplayQuery( &$tables, &$fields, &$conds,
 702                                                                                 &$join_conds, &$options, $filter_tag = '' ) {
 703                 global $wgUseTagFilter;
 704
 705                 // Normalize to arrays
 706                 $tables = (array)$tables;
 707                 $fields = (array)$fields;
 708                 $conds = (array)$conds;
 709                 $options = (array)$options;
 710
 711                 // Figure out which ID field to use
 712                 if ( in_array( 'recentchanges', $tables ) ) {
 713                         $join_cond = 'ct_rc_id=rc_id';
 714                 } elseif ( in_array( 'logging', $tables ) ) {
 715                         $join_cond = 'ct_log_id=log_id';
 716                 } elseif ( in_array( 'revision', $tables ) ) {
 717                         $join_cond = 'ct_rev_id=rev_id';
 718                 } elseif ( in_array( 'archive', $tables ) ) {
 719                         $join_cond = 'ct_rev_id=ar_rev_id';
 720                 } else {
 721                         throw new MWException( 'Unable to determine appropriate JOIN condition for tagging.' );
 722                 }
 723
 724                 $fields['ts_tags'] = wfGetDB( DB_REPLICA )->buildGroupConcatField(
 725                         ',', 'change_tag', 'ct_tag', $join_cond
 726                 );
 727
 728                 if ( $wgUseTagFilter && $filter_tag ) {
 729                         // Somebody wants to filter on a tag.
 730                         // Add an INNER JOIN on change_tag
 731
 732                         $tables[] = 'change_tag';
 733                         $join_conds['change_tag'] = [ 'INNER JOIN', $join_cond ];
 734                         $conds['ct_tag'] = $filter_tag;
 735                         if (
 736                                 is_array( $filter_tag ) && count( $filter_tag ) > 1 &&
 737                                 !in_array( 'DISTINCT', $options )
 738                         ) {
 739                                 $options[] = 'DISTINCT';
 740                         }
 741                 }
 742         }
 743
 744         /**
 745          * Build a text box to select a change tag
 746          *
 747          * @param string $selected Tag to select by default
 748          * @param bool $ooui Use an OOUI TextInputWidget as selector instead of a non-OOUI input field
 749          *        You need to call OutputPage::enableOOUI() yourself.
 750          * @param IContextSource|null $context
 751          * @note Even though it takes null as a valid argument, an IContextSource is preferred
 752          *       in a new code, as the null value can change in the future
 753          * @return array an array of (label, selector)
 754          */
 755         public static function buildTagFilterSelector(
 756                 $selected = '', $ooui = false, IContextSource $context = null
 757         ) {
 758                 if ( !$context ) {
 759                         $context = RequestContext::getMain();
 760                 }
 761
 762                 $config = $context->getConfig();
 763                 if ( !$config->get( 'UseTagFilter' ) || !count( self::listDefinedTags() ) ) {
 764                         return [];
 765                 }
 766
 767                 $data = [
 768                         Html::rawElement(
 769                                 'label',
 770                                 [ 'for' => 'tagfilter' ],
 771                                 $context->msg( 'tag-filter' )->parse()
 772                         )
 773                 ];
 774
 775                 if ( $ooui ) {
 776                         $data[] = new OOUI\TextInputWidget( [
 777                                 'id' => 'tagfilter',
 778                                 'name' => 'tagfilter',
 779                                 'value' => $selected,
 780                                 'classes' => 'mw-tagfilter-input',
 781                         ] );
 782                 } else {
 783                         $data[] = Xml::input(
 784                                 'tagfilter',
 785                                 20,
 786                                 $selected,
 787                                 [ 'class' => 'mw-tagfilter-input mw-ui-input mw-ui-input-inline', 'id' => 'tagfilter' ]
 788                         );
 789                 }
 790
 791                 return $data;
 792         }
 793
 794         /**
 795          * Defines a tag in the valid_tag table, without checking that the tag name
 796          * is valid.
 797          * Extensions should NOT use this function; they can use the ListDefinedTags
 798          * hook instead.
 799          *
 800          * @param string $tag Tag to create
 801          * @since 1.25
 802          */
 803         public static function defineTag( $tag ) {
 804                 $dbw = wfGetDB( DB_MASTER );
 805                 $dbw->replace( 'valid_tag',
 806                         [ 'vt_tag' ],
 807                         [ 'vt_tag' => $tag ],
 808                         __METHOD__ );
 809
 810                 // clear the memcache of defined tags
 811                 self::purgeTagCacheAll();
 812         }
 813
 814         /**
 815          * Removes a tag from the valid_tag table. The tag may remain in use by
 816          * extensions, and may still show up as 'defined' if an extension is setting
 817          * it from the ListDefinedTags hook.
 818          *
 819          * @param string $tag Tag to remove
 820          * @since 1.25
 821          */
 822         public static function undefineTag( $tag ) {
 823                 $dbw = wfGetDB( DB_MASTER );
 824                 $dbw->delete( 'valid_tag', [ 'vt_tag' => $tag ], __METHOD__ );
 825
 826                 // clear the memcache of defined tags
 827                 self::purgeTagCacheAll();
 828         }
 829
 830         /**
 831          * Writes a tag action into the tag management log.
 832          *
 833          * @param string $action
 834          * @param string $tag
 835          * @param string $reason
 836          * @param User $user Who to attribute the action to
 837          * @param int $tagCount For deletion only, how many usages the tag had before
 838          * it was deleted.
 839          * @param array $logEntryTags Change tags to apply to the entry
 840          * that will be created in the tag management log
 841          * @return int ID of the inserted log entry
 842          * @since 1.25
 843          */
 844         protected static function logTagManagementAction( $action, $tag, $reason,
 845                 User $user, $tagCount = null, array $logEntryTags = []
 846         ) {
 847                 $dbw = wfGetDB( DB_MASTER );
 848
 849                 $logEntry = new ManualLogEntry( 'managetags', $action );
 850                 $logEntry->setPerformer( $user );
 851                 // target page is not relevant, but it has to be set, so we just put in
 852                 // the title of Special:Tags
 853                 $logEntry->setTarget( Title::newFromText( 'Special:Tags' ) );
 854                 $logEntry->setComment( $reason );
 855
 856                 $params = [ '4::tag' => $tag ];
 857                 if ( !is_null( $tagCount ) ) {
 858                         $params['5:number:count'] = $tagCount;
 859                 }
 860                 $logEntry->setParameters( $params );
 861                 $logEntry->setRelations( [ 'Tag' => $tag ] );
 862                 $logEntry->setTags( $logEntryTags );
 863
 864                 $logId = $logEntry->insert( $dbw );
 865                 $logEntry->publish( $logId );
 866                 return $logId;
 867         }
 868
 869         /**
 870          * Is it OK to allow the user to activate this tag?
 871          *
 872          * @param string $tag Tag that you are interested in activating
 873          * @param User|null $user User whose permission you wish to check, or null if
 874          * you don't care (e.g. maintenance scripts)
 875          * @return Status
 876          * @since 1.25
 877          */
 878         public static function canActivateTag( $tag, User $user = null ) {
 879                 if ( !is_null( $user ) ) {
 880                         if ( !$user->isAllowed( 'managechangetags' ) ) {
 881                                 return Status::newFatal( 'tags-manage-no-permission' );
 882                         } elseif ( $user->isBlocked() ) {
 883                                 return Status::newFatal( 'tags-manage-blocked', $user->getName() );
 884                         }
 885                 }
 886
 887                 // defined tags cannot be activated (a defined tag is either extension-
 888                 // defined, in which case the extension chooses whether or not to active it;
 889                 // or user-defined, in which case it is considered active)
 890                 $definedTags = self::listDefinedTags();
 891                 if ( in_array( $tag, $definedTags ) ) {
 892                         return Status::newFatal( 'tags-activate-not-allowed', $tag );
 893                 }
 894
 895                 // non-existing tags cannot be activated
 896                 $tagUsage = self::tagUsageStatistics();
 897                 if ( !isset( $tagUsage[$tag] ) ) { // we already know the tag is undefined
 898                         return Status::newFatal( 'tags-activate-not-found', $tag );
 899                 }
 900
 901                 return Status::newGood();
 902         }
 903
 904         /**
 905          * Activates a tag, checking whether it is allowed first, and adding a log
 906          * entry afterwards.
 907          *
 908          * Includes a call to ChangeTag::canActivateTag(), so your code doesn't need
 909          * to do that.
 910          *
 911          * @param string $tag
 912          * @param string $reason
 913          * @param User $user Who to give credit for the action
 914          * @param bool $ignoreWarnings Can be used for API interaction, default false
 915          * @param array $logEntryTags Change tags to apply to the entry
 916          * that will be created in the tag management log
 917          * @return Status If successful, the Status contains the ID of the added log
 918          * entry as its value
 919          * @since 1.25
 920          */
 921         public static function activateTagWithChecks( $tag, $reason, User $user,
 922                 $ignoreWarnings = false, array $logEntryTags = []
 923         ) {
 924                 // are we allowed to do this?
 925                 $result = self::canActivateTag( $tag, $user );
 926                 if ( $ignoreWarnings ? !$result->isOK() : !$result->isGood() ) {
 927                         $result->value = null;
 928                         return $result;
 929                 }
 930
 931                 // do it!
 932                 self::defineTag( $tag );
 933
 934                 // log it
 935                 $logId = self::logTagManagementAction( 'activate', $tag, $reason, $user,
 936                         null, $logEntryTags );
 937
 938                 return Status::newGood( $logId );
 939         }
 940
 941         /**
 942          * Is it OK to allow the user to deactivate this tag?
 943          *
 944          * @param string $tag Tag that you are interested in deactivating
 945          * @param User|null $user User whose permission you wish to check, or null if
 946          * you don't care (e.g. maintenance scripts)
 947          * @return Status
 948          * @since 1.25
 949          */
 950         public static function canDeactivateTag( $tag, User $user = null ) {
 951                 if ( !is_null( $user ) ) {
 952                         if ( !$user->isAllowed( 'managechangetags' ) ) {
 953                                 return Status::newFatal( 'tags-manage-no-permission' );
 954                         } elseif ( $user->isBlocked() ) {
 955                                 return Status::newFatal( 'tags-manage-blocked', $user->getName() );
 956                         }
 957                 }
 958
 959                 // only explicitly-defined tags can be deactivated
 960                 $explicitlyDefinedTags = self::listExplicitlyDefinedTags();
 961                 if ( !in_array( $tag, $explicitlyDefinedTags ) ) {
 962                         return Status::newFatal( 'tags-deactivate-not-allowed', $tag );
 963                 }
 964                 return Status::newGood();
 965         }
 966
 967         /**
 968          * Deactivates a tag, checking whether it is allowed first, and adding a log
 969          * entry afterwards.
 970          *
 971          * Includes a call to ChangeTag::canDeactivateTag(), so your code doesn't need
 972          * to do that.
 973          *
 974          * @param string $tag
 975          * @param string $reason
 976          * @param User $user Who to give credit for the action
 977          * @param bool $ignoreWarnings Can be used for API interaction, default false
 978          * @param array $logEntryTags Change tags to apply to the entry
 979          * that will be created in the tag management log
 980          * @return Status If successful, the Status contains the ID of the added log
 981          * entry as its value
 982          * @since 1.25
 983          */
 984         public static function deactivateTagWithChecks( $tag, $reason, User $user,
 985                 $ignoreWarnings = false, array $logEntryTags = []
 986         ) {
 987                 // are we allowed to do this?
 988                 $result = self::canDeactivateTag( $tag, $user );
 989                 if ( $ignoreWarnings ? !$result->isOK() : !$result->isGood() ) {
 990                         $result->value = null;
 991                         return $result;
 992                 }
 993
 994                 // do it!
 995                 self::undefineTag( $tag );
 996
 997                 // log it
 998                 $logId = self::logTagManagementAction( 'deactivate', $tag, $reason, $user,
 999                         null, $logEntryTags );
1000
1001                 return Status::newGood( $logId );
1002         }
1003
1004         /**
1005          * Is the tag name valid?
1006          *
1007          * @param string $tag Tag that you are interested in creating
1008          * @return Status
1009          * @since 1.30
1010          */
1011         public static function isTagNameValid( $tag ) {
1012                 // no empty tags
1013                 if ( $tag === '' ) {
1014                         return Status::newFatal( 'tags-create-no-name' );
1015                 }
1016
1017                 // tags cannot contain commas (used as a delimiter in tag_summary table),
1018                 // pipe (used as a delimiter between multiple tags in
1019                 // SpecialRecentchanges and friends), or slashes (would break tag description messages in
1020                 // MediaWiki namespace)
1021                 if ( strpos( $tag, ',' ) !== false || strpos( $tag, '|' ) !== false
1022                         || strpos( $tag, '/' ) !== false ) {
1023                         return Status::newFatal( 'tags-create-invalid-chars' );
1024                 }
1025
1026                 // could the MediaWiki namespace description messages be created?
1027                 $title = Title::makeTitleSafe( NS_MEDIAWIKI, "Tag-$tag-description" );
1028                 if ( is_null( $title ) ) {
1029                         return Status::newFatal( 'tags-create-invalid-title-chars' );
1030                 }
1031
1032                 return Status::newGood();
1033         }
1034
1035         /**
1036          * Is it OK to allow the user to create this tag?
1037          *
1038          * @param string $tag Tag that you are interested in creating
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 canCreateTag( $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                 $status = self::isTagNameValid( $tag );
1054                 if ( !$status->isGood() ) {
1055                         return $status;
1056                 }
1057
1058                 // does the tag already exist?
1059                 $tagUsage = self::tagUsageStatistics();
1060                 if ( isset( $tagUsage[$tag] ) || in_array( $tag, self::listDefinedTags() ) ) {
1061                         return Status::newFatal( 'tags-create-already-exists', $tag );
1062                 }
1063
1064                 // check with hooks
1065                 $canCreateResult = Status::newGood();
1066                 Hooks::run( 'ChangeTagCanCreate', [ $tag, $user, &$canCreateResult ] );
1067                 return $canCreateResult;
1068         }
1069
1070         /**
1071          * Creates a tag by adding a row to the `valid_tag` table.
1072          *
1073          * Includes a call to ChangeTag::canDeleteTag(), so your code doesn't need to
1074          * do that.
1075          *
1076          * @param string $tag
1077          * @param string $reason
1078          * @param User $user Who to give credit for the action
1079          * @param bool $ignoreWarnings Can be used for API interaction, default false
1080          * @param array $logEntryTags Change tags to apply to the entry
1081          * that will be created in the tag management log
1082          * @return Status If successful, the Status contains the ID of the added log
1083          * entry as its value
1084          * @since 1.25
1085          */
1086         public static function createTagWithChecks( $tag, $reason, User $user,
1087                 $ignoreWarnings = false, array $logEntryTags = []
1088         ) {
1089                 // are we allowed to do this?
1090                 $result = self::canCreateTag( $tag, $user );
1091                 if ( $ignoreWarnings ? !$result->isOK() : !$result->isGood() ) {
1092                         $result->value = null;
1093                         return $result;
1094                 }
1095
1096                 // do it!
1097                 self::defineTag( $tag );
1098
1099                 // log it
1100                 $logId = self::logTagManagementAction( 'create', $tag, $reason, $user,
1101                         null, $logEntryTags );
1102
1103                 return Status::newGood( $logId );
1104         }
1105
1106         /**
1107          * Permanently removes all traces of a tag from the DB. Good for removing
1108          * misspelt or temporary tags.
1109          *
1110          * This function should be directly called by maintenance scripts only, never
1111          * by user-facing code. See deleteTagWithChecks() for functionality that can
1112          * safely be exposed to users.
1113          *
1114          * @param string $tag Tag to remove
1115          * @return Status The returned status will be good unless a hook changed it
1116          * @since 1.25
1117          */
1118         public static function deleteTagEverywhere( $tag ) {
1119                 $dbw = wfGetDB( DB_MASTER );
1120                 $dbw->startAtomic( __METHOD__ );
1121
1122                 // delete from valid_tag
1123                 self::undefineTag( $tag );
1124
1125                 // find out which revisions use this tag, so we can delete from tag_summary
1126                 $result = $dbw->select( 'change_tag',
1127                         [ 'ct_rc_id', 'ct_log_id', 'ct_rev_id', 'ct_tag' ],
1128                         [ 'ct_tag' => $tag ],
1129                         __METHOD__ );
1130                 foreach ( $result as $row ) {
1131                         // remove the tag from the relevant row of tag_summary
1132                         $tagsToAdd = [];
1133                         $tagsToRemove = [ $tag ];
1134                         self::updateTagSummaryRow( $tagsToAdd, $tagsToRemove, $row->ct_rc_id,
1135                                 $row->ct_rev_id, $row->ct_log_id );
1136                 }
1137
1138                 // delete from change_tag
1139                 $dbw->delete( 'change_tag', [ 'ct_tag' => $tag ], __METHOD__ );
1140
1141                 $dbw->endAtomic( __METHOD__ );
1142
1143                 // give extensions a chance
1144                 $status = Status::newGood();
1145                 Hooks::run( 'ChangeTagAfterDelete', [ $tag, &$status ] );
1146                 // let's not allow error results, as the actual tag deletion succeeded
1147                 if ( !$status->isOK() ) {
1148                         wfDebug( 'ChangeTagAfterDelete error condition downgraded to warning' );
1149                         $status->setOK( true );
1150                 }
1151
1152                 // clear the memcache of defined tags
1153                 self::purgeTagCacheAll();
1154
1155                 return $status;
1156         }
1157
1158         /**
1159          * Is it OK to allow the user to delete this tag?
1160          *
1161          * @param string $tag Tag that you are interested in deleting
1162          * @param User|null $user User whose permission you wish to check, or null if
1163          * you don't care (e.g. maintenance scripts)
1164          * @return Status
1165          * @since 1.25
1166          */
1167         public static function canDeleteTag( $tag, User $user = null ) {
1168                 $tagUsage = self::tagUsageStatistics();
1169
1170                 if ( !is_null( $user ) ) {
1171                         if ( !$user->isAllowed( 'deletechangetags' ) ) {
1172                                 return Status::newFatal( 'tags-delete-no-permission' );
1173                         } elseif ( $user->isBlocked() ) {
1174                                 return Status::newFatal( 'tags-manage-blocked', $user->getName() );
1175                         }
1176                 }
1177
1178                 if ( !isset( $tagUsage[$tag] ) && !in_array( $tag, self::listDefinedTags() ) ) {
1179                         return Status::newFatal( 'tags-delete-not-found', $tag );
1180                 }
1181
1182                 if ( isset( $tagUsage[$tag] ) && $tagUsage[$tag] > self::MAX_DELETE_USES ) {
1183                         return Status::newFatal( 'tags-delete-too-many-uses', $tag, self::MAX_DELETE_USES );
1184                 }
1185
1186                 $softwareDefined = self::listSoftwareDefinedTags();
1187                 if ( in_array( $tag, $softwareDefined ) ) {
1188                         // extension-defined tags can't be deleted unless the extension
1189                         // specifically allows it
1190                         $status = Status::newFatal( 'tags-delete-not-allowed' );
1191                 } else {
1192                         // user-defined tags are deletable unless otherwise specified
1193                         $status = Status::newGood();
1194                 }
1195
1196                 Hooks::run( 'ChangeTagCanDelete', [ $tag, $user, &$status ] );
1197                 return $status;
1198         }
1199
1200         /**
1201          * Deletes a tag, checking whether it is allowed first, and adding a log entry
1202          * afterwards.
1203          *
1204          * Includes a call to ChangeTag::canDeleteTag(), so your code doesn't need to
1205          * do that.
1206          *
1207          * @param string $tag
1208          * @param string $reason
1209          * @param User $user Who to give credit for the action
1210          * @param bool $ignoreWarnings Can be used for API interaction, default false
1211          * @param array $logEntryTags Change tags to apply to the entry
1212          * that will be created in the tag management log
1213          * @return Status If successful, the Status contains the ID of the added log
1214          * entry as its value
1215          * @since 1.25
1216          */
1217         public static function deleteTagWithChecks( $tag, $reason, User $user,
1218                 $ignoreWarnings = false, array $logEntryTags = []
1219         ) {
1220                 // are we allowed to do this?
1221                 $result = self::canDeleteTag( $tag, $user );
1222                 if ( $ignoreWarnings ? !$result->isOK() : !$result->isGood() ) {
1223                         $result->value = null;
1224                         return $result;
1225                 }
1226
1227                 // store the tag usage statistics
1228                 $tagUsage = self::tagUsageStatistics();
1229                 $hitcount = isset( $tagUsage[$tag] ) ? $tagUsage[$tag] : 0;
1230
1231                 // do it!
1232                 $deleteResult = self::deleteTagEverywhere( $tag );
1233                 if ( !$deleteResult->isOK() ) {
1234                         return $deleteResult;
1235                 }
1236
1237                 // log it
1238                 $logId = self::logTagManagementAction( 'delete', $tag, $reason, $user,
1239                         $hitcount, $logEntryTags );
1240
1241                 $deleteResult->value = $logId;
1242                 return $deleteResult;
1243         }
1244
1245         /**
1246          * Lists those tags which core or extensions report as being "active".
1247          *
1248          * @return array
1249          * @since 1.25
1250          */
1251         public static function listSoftwareActivatedTags() {
1252                 // core active tags
1253                 $tags = self::getSoftwareTags();
1254                 if ( !Hooks::isRegistered( 'ChangeTagsListActive' ) ) {
1255                         return $tags;
1256                 }
1257                 $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
1258                 return $cache->getWithSetCallback(
1259                         $cache->makeKey( 'active-tags' ),
1260                         WANObjectCache::TTL_MINUTE * 5,
1261                         function ( $oldValue, &$ttl, array &$setOpts ) use ( $tags ) {
1262                                 $setOpts += Database::getCacheSetOptions( wfGetDB( DB_REPLICA ) );
1263
1264                                 // Ask extensions which tags they consider active
1265                                 Hooks::run( 'ChangeTagsListActive', [ &$tags ] );
1266                                 return $tags;
1267                         },
1268                         [
1269                                 'checkKeys' => [ $cache->makeKey( 'active-tags' ) ],
1270                                 'lockTSE' => WANObjectCache::TTL_MINUTE * 5,
1271                                 'pcTTL' => WANObjectCache::TTL_PROC_LONG
1272                         ]
1273                 );
1274         }
1275
1276         /**
1277          * @see listSoftwareActivatedTags
1278          * @deprecated since 1.28 call listSoftwareActivatedTags directly
1279          * @return array
1280          */
1281         public static function listExtensionActivatedTags() {
1282                 wfDeprecated( __METHOD__, '1.28' );
1283                 return self::listSoftwareActivatedTags();
1284         }
1285
1286         /**
1287          * Basically lists defined tags which count even if they aren't applied to anything.
1288          * It returns a union of the results of listExplicitlyDefinedTags() and
1289          * listExtensionDefinedTags().
1290          *
1291          * @return string[] Array of strings: tags
1292          */
1293         public static function listDefinedTags() {
1294                 $tags1 = self::listExplicitlyDefinedTags();
1295                 $tags2 = self::listSoftwareDefinedTags();
1296                 return array_values( array_unique( array_merge( $tags1, $tags2 ) ) );
1297         }
1298
1299         /**
1300          * Lists tags explicitly defined in the `valid_tag` table of the database.
1301          * Tags in table 'change_tag' which are not in table 'valid_tag' are not
1302          * included.
1303          *
1304          * Tries memcached first.
1305          *
1306          * @return string[] Array of strings: tags
1307          * @since 1.25
1308          */
1309         public static function listExplicitlyDefinedTags() {
1310                 $fname = __METHOD__;
1311
1312                 $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
1313                 return $cache->getWithSetCallback(
1314                         $cache->makeKey( 'valid-tags-db' ),
1315                         WANObjectCache::TTL_MINUTE * 5,
1316                         function ( $oldValue, &$ttl, array &$setOpts ) use ( $fname ) {
1317                                 $dbr = wfGetDB( DB_REPLICA );
1318
1319                                 $setOpts += Database::getCacheSetOptions( $dbr );
1320
1321                                 $tags = $dbr->selectFieldValues( 'valid_tag', 'vt_tag', [], $fname );
1322
1323                                 return array_filter( array_unique( $tags ) );
1324                         },
1325                         [
1326                                 'checkKeys' => [ $cache->makeKey( 'valid-tags-db' ) ],
1327                                 'lockTSE' => WANObjectCache::TTL_MINUTE * 5,
1328                                 'pcTTL' => WANObjectCache::TTL_PROC_LONG
1329                         ]
1330                 );
1331         }
1332
1333         /**
1334          * Lists tags defined by core or extensions using the ListDefinedTags hook.
1335          * Extensions need only define those tags they deem to be in active use.
1336          *
1337          * Tries memcached first.
1338          *
1339          * @return string[] Array of strings: tags
1340          * @since 1.25
1341          */
1342         public static function listSoftwareDefinedTags() {
1343                 // core defined tags
1344                 $tags = self::getSoftwareTags( true );
1345                 if ( !Hooks::isRegistered( 'ListDefinedTags' ) ) {
1346                         return $tags;
1347                 }
1348                 $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
1349                 return $cache->getWithSetCallback(
1350                         $cache->makeKey( 'valid-tags-hook' ),
1351                         WANObjectCache::TTL_MINUTE * 5,
1352                         function ( $oldValue, &$ttl, array &$setOpts ) use ( $tags ) {
1353                                 $setOpts += Database::getCacheSetOptions( wfGetDB( DB_REPLICA ) );
1354
1355                                 Hooks::run( 'ListDefinedTags', [ &$tags ] );
1356                                 return array_filter( array_unique( $tags ) );
1357                         },
1358                         [
1359                                 'checkKeys' => [ $cache->makeKey( 'valid-tags-hook' ) ],
1360                                 'lockTSE' => WANObjectCache::TTL_MINUTE * 5,
1361                                 'pcTTL' => WANObjectCache::TTL_PROC_LONG
1362                         ]
1363                 );
1364         }
1365
1366         /**
1367          * Call listSoftwareDefinedTags directly
1368          *
1369          * @see listSoftwareDefinedTags
1370          * @deprecated since 1.28
1371          * @return array
1372          */
1373         public static function listExtensionDefinedTags() {
1374                 wfDeprecated( __METHOD__, '1.28' );
1375                 return self::listSoftwareDefinedTags();
1376         }
1377
1378         /**
1379          * Invalidates the short-term cache of defined tags used by the
1380          * list*DefinedTags functions, as well as the tag statistics cache.
1381          * @since 1.25
1382          */
1383         public static function purgeTagCacheAll() {
1384                 $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
1385
1386                 $cache->touchCheckKey( $cache->makeKey( 'active-tags' ) );
1387                 $cache->touchCheckKey( $cache->makeKey( 'valid-tags-db' ) );
1388                 $cache->touchCheckKey( $cache->makeKey( 'valid-tags-hook' ) );
1389
1390                 self::purgeTagUsageCache();
1391         }
1392
1393         /**
1394          * Invalidates the tag statistics cache only.
1395          * @since 1.25
1396          */
1397         public static function purgeTagUsageCache() {
1398                 $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
1399
1400                 $cache->touchCheckKey( $cache->makeKey( 'change-tag-statistics' ) );
1401         }
1402
1403         /**
1404          * Returns a map of any tags used on the wiki to number of edits
1405          * tagged with them, ordered descending by the hitcount.
1406          * This does not include tags defined somewhere that have never been applied.
1407          *
1408          * Keeps a short-term cache in memory, so calling this multiple times in the
1409          * same request should be fine.
1410          *
1411          * @return array Array of string => int
1412          */
1413         public static function tagUsageStatistics() {
1414                 $fname = __METHOD__;
1415                 $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
1416                 return $cache->getWithSetCallback(
1417                         $cache->makeKey( 'change-tag-statistics' ),
1418                         WANObjectCache::TTL_MINUTE * 5,
1419                         function ( $oldValue, &$ttl, array &$setOpts ) use ( $fname ) {
1420                                 $dbr = wfGetDB( DB_REPLICA, 'vslow' );
1421
1422                                 $setOpts += Database::getCacheSetOptions( $dbr );
1423
1424                                 $res = $dbr->select(
1425                                         'change_tag',
1426                                         [ 'ct_tag', 'hitcount' => 'count(*)' ],
1427                                         [],
1428                                         $fname,
1429                                         [ 'GROUP BY' => 'ct_tag', 'ORDER BY' => 'hitcount DESC' ]
1430                                 );
1431
1432                                 $out = [];
1433                                 foreach ( $res as $row ) {
1434                                         $out[$row->ct_tag] = $row->hitcount;
1435                                 }
1436
1437                                 return $out;
1438                         },
1439                         [
1440                                 'checkKeys' => [ $cache->makeKey( 'change-tag-statistics' ) ],
1441                                 'lockTSE' => WANObjectCache::TTL_MINUTE * 5,
1442                                 'pcTTL' => WANObjectCache::TTL_PROC_LONG
1443                         ]
1444                 );
1445         }
1446
1447         /**
1448          * Indicate whether change tag editing UI is relevant
1449          *
1450          * Returns true if the user has the necessary right and there are any
1451          * editable tags defined.
1452          *
1453          * This intentionally doesn't check "any addable || any deletable", because
1454          * it seems like it would be more confusing than useful if the checkboxes
1455          * suddenly showed up because some abuse filter stopped defining a tag and
1456          * then suddenly disappeared when someone deleted all uses of that tag.
1457          *
1458          * @param User $user
1459          * @return bool
1460          */
1461         public static function showTagEditingUI( User $user ) {
1462                 return $user->isAllowed( 'changetags' ) && (bool)self::listExplicitlyDefinedTags();
1463         }
1464 }