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          * Get truncated message for the tag's long description.
 186          *
 187          * @param string $tag Tag name.
 188          * @param int $length Maximum length of truncated message, including ellipsis.
 189          * @param IContextSource $context
 190          *
 191          * @return string Truncated long tag description.
 192          */
 193         public static function truncateTagDescription( $tag, $length, IContextSource $context ) {
 194                 $originalDesc = self::tagLongDescriptionMessage( $tag, $context );
 195                 // If there is no tag description, return empty string
 196                 if ( !$originalDesc ) {
 197                         return '';
 198                 }
 199
 200                 $taglessDesc = Sanitizer::stripAllTags( $originalDesc->parse() );
 201                 $escapedDesc = Sanitizer::escapeHtmlAllowEntities( $taglessDesc );
 202
 203                 return $context->getLanguage()->truncateForVisual( $escapedDesc, $length );
 204         }
 205
 206         /**
 207          * Add tags to a change given its rc_id, rev_id and/or log_id
 208          *
 209          * @param string|string[] $tags Tags to add to the change
 210          * @param int|null $rc_id The rc_id of the change to add the tags to
 211          * @param int|null $rev_id The rev_id of the change to add the tags to
 212          * @param int|null $log_id The log_id of the change to add the tags to
 213          * @param string $params Params to put in the ct_params field of table 'change_tag'
 214          * @param RecentChange|null $rc Recent change, in case the tagging accompanies the action
 215          * (this should normally be the case)
 216          *
 217          * @throws MWException
 218          * @return bool False if no changes are made, otherwise true
 219          */
 220         public static function addTags( $tags, $rc_id = null, $rev_id = null,
 221                 $log_id = null, $params = null, RecentChange $rc = null
 222         ) {
 223                 $result = self::updateTags( $tags, null, $rc_id, $rev_id, $log_id, $params, $rc );
 224                 return (bool)$result[0];
 225         }
 226
 227         /**
 228          * Add and remove tags to/from a change given its rc_id, rev_id and/or log_id,
 229          * without verifying that the tags exist or are valid. If a tag is present in
 230          * both $tagsToAdd and $tagsToRemove, it will be removed.
 231          *
 232          * This function should only be used by extensions to manipulate tags they
 233          * have registered using the ListDefinedTags hook. When dealing with user
 234          * input, call updateTagsWithChecks() instead.
 235          *
 236          * @param string|array|null $tagsToAdd Tags to add to the change
 237          * @param string|array|null $tagsToRemove Tags to remove from the change
 238          * @param int|null &$rc_id The rc_id of the change to add the tags to.
 239          * Pass a variable whose value is null if the rc_id is not relevant or unknown.
 240          * @param int|null &$rev_id The rev_id of the change to add the tags to.
 241          * Pass a variable whose value is null if the rev_id is not relevant or unknown.
 242          * @param int|null &$log_id The log_id of the change to add the tags to.
 243          * Pass a variable whose value is null if the log_id is not relevant or unknown.
 244          * @param string $params Params to put in the ct_params field of table
 245          * 'change_tag' when adding tags
 246          * @param RecentChange|null $rc Recent change being tagged, in case the tagging accompanies
 247          * the action
 248          * @param User|null $user Tagging user, in case the tagging is subsequent to the tagged action
 249          *
 250          * @throws MWException When $rc_id, $rev_id and $log_id are all null
 251          * @return array Index 0 is an array of tags actually added, index 1 is an
 252          * array of tags actually removed, index 2 is an array of tags present on the
 253          * revision or log entry before any changes were made
 254          *
 255          * @since 1.25
 256          */
 257         public static function updateTags( $tagsToAdd, $tagsToRemove, &$rc_id = null,
 258                 &$rev_id = null, &$log_id = null, $params = null, RecentChange $rc = null,
 259                 User $user = null
 260         ) {
 261                 $tagsToAdd = array_filter( (array)$tagsToAdd ); // Make sure we're submitting all tags...
 262                 $tagsToRemove = array_filter( (array)$tagsToRemove );
 263
 264                 if ( !$rc_id && !$rev_id && !$log_id ) {
 265                         throw new MWException( 'At least one of: RCID, revision ID, and log ID MUST be ' .
 266                                 'specified when adding or removing a tag from a change!' );
 267                 }
 268
 269                 $dbw = wfGetDB( DB_MASTER );
 270
 271                 // Might as well look for rcids and so on.
 272                 if ( !$rc_id ) {
 273                         // Info might be out of date, somewhat fractionally, on replica DB.
 274                         // LogEntry/LogPage and WikiPage match rev/log/rc timestamps,
 275                         // so use that relation to avoid full table scans.
 276                         if ( $log_id ) {
 277                                 $rc_id = $dbw->selectField(
 278                                         [ 'logging', 'recentchanges' ],
 279                                         'rc_id',
 280                                         [
 281                                                 'log_id' => $log_id,
 282                                                 'rc_timestamp = log_timestamp',
 283                                                 'rc_logid = log_id'
 284                                         ],
 285                                         __METHOD__
 286                                 );
 287                         } elseif ( $rev_id ) {
 288                                 $rc_id = $dbw->selectField(
 289                                         [ 'revision', 'recentchanges' ],
 290                                         'rc_id',
 291                                         [
 292                                                 'rev_id' => $rev_id,
 293                                                 'rc_timestamp = rev_timestamp',
 294                                                 'rc_this_oldid = rev_id'
 295                                         ],
 296                                         __METHOD__
 297                                 );
 298                         }
 299                 } elseif ( !$log_id && !$rev_id ) {
 300                         // Info might be out of date, somewhat fractionally, on replica DB.
 301                         $log_id = $dbw->selectField(
 302                                 'recentchanges',
 303                                 'rc_logid',
 304                                 [ 'rc_id' => $rc_id ],
 305                                 __METHOD__
 306                         );
 307                         $rev_id = $dbw->selectField(
 308                                 'recentchanges',
 309                                 'rc_this_oldid',
 310                                 [ 'rc_id' => $rc_id ],
 311                                 __METHOD__
 312                         );
 313                 }
 314
 315                 if ( $log_id && !$rev_id ) {
 316                         $rev_id = $dbw->selectField(
 317                                 'log_search',
 318                                 'ls_value',
 319                                 [ 'ls_field' => 'associated_rev_id', 'ls_log_id' => $log_id ],
 320                                 __METHOD__
 321                         );
 322                 } elseif ( !$log_id && $rev_id ) {
 323                         $log_id = $dbw->selectField(
 324                                 'log_search',
 325                                 'ls_log_id',
 326                                 [ 'ls_field' => 'associated_rev_id', 'ls_value' => $rev_id ],
 327                                 __METHOD__
 328                         );
 329                 }
 330
 331                 // update the tag_summary row
 332                 $prevTags = [];
 333                 if ( !self::updateTagSummaryRow( $tagsToAdd, $tagsToRemove, $rc_id, $rev_id,
 334                         $log_id, $prevTags )
 335                 ) {
 336                         // nothing to do
 337                         return [ [], [], $prevTags ];
 338                 }
 339
 340                 // insert a row into change_tag for each new tag
 341                 if ( count( $tagsToAdd ) ) {
 342                         $tagsRows = [];
 343                         foreach ( $tagsToAdd as $tag ) {
 344                                 // Filter so we don't insert NULLs as zero accidentally.
 345                                 // Keep in mind that $rc_id === null means "I don't care/know about the
 346                                 // rc_id, just delete $tag on this revision/log entry". It doesn't
 347                                 // mean "only delete tags on this revision/log WHERE rc_id IS NULL".
 348                                 $tagsRows[] = array_filter(
 349                                         [
 350                                                 'ct_tag' => $tag,
 351                                                 'ct_rc_id' => $rc_id,
 352                                                 'ct_log_id' => $log_id,
 353                                                 'ct_rev_id' => $rev_id,
 354                                                 'ct_params' => $params
 355                                         ]
 356                                 );
 357                         }
 358
 359                         $dbw->insert( 'change_tag', $tagsRows, __METHOD__, [ 'IGNORE' ] );
 360                 }
 361
 362                 // delete from change_tag
 363                 if ( count( $tagsToRemove ) ) {
 364                         foreach ( $tagsToRemove as $tag ) {
 365                                 $conds = array_filter(
 366                                         [
 367                                                 'ct_tag' => $tag,
 368                                                 'ct_rc_id' => $rc_id,
 369                                                 'ct_log_id' => $log_id,
 370                                                 'ct_rev_id' => $rev_id
 371                                         ]
 372                                 );
 373                                 $dbw->delete( 'change_tag', $conds, __METHOD__ );
 374                         }
 375                 }
 376
 377                 self::purgeTagUsageCache();
 378
 379                 Hooks::run( 'ChangeTagsAfterUpdateTags', [ $tagsToAdd, $tagsToRemove, $prevTags,
 380                         $rc_id, $rev_id, $log_id, $params, $rc, $user ] );
 381
 382                 return [ $tagsToAdd, $tagsToRemove, $prevTags ];
 383         }
 384
 385         /**
 386          * Adds or removes a given set of tags to/from the relevant row of the
 387          * tag_summary table. Modifies the tagsToAdd and tagsToRemove arrays to
 388          * reflect the tags that were actually added and/or removed.
 389          *
 390          * @param array &$tagsToAdd
 391          * @param array &$tagsToRemove If a tag is present in both $tagsToAdd and
 392          * $tagsToRemove, it will be removed
 393          * @param int|null $rc_id Null if not known or not applicable
 394          * @param int|null $rev_id Null if not known or not applicable
 395          * @param int|null $log_id Null if not known or not applicable
 396          * @param array &$prevTags Optionally outputs a list of the tags that were
 397          * in the tag_summary row to begin with
 398          * @return bool True if any modifications were made, otherwise false
 399          * @since 1.25
 400          */
 401         protected static function updateTagSummaryRow( &$tagsToAdd, &$tagsToRemove,
 402                 $rc_id, $rev_id, $log_id, &$prevTags = []
 403         ) {
 404                 $dbw = wfGetDB( DB_MASTER );
 405
 406                 $tsConds = array_filter( [
 407                         'ts_rc_id' => $rc_id,
 408                         'ts_rev_id' => $rev_id,
 409                         'ts_log_id' => $log_id
 410                 ] );
 411
 412                 // Can't both add and remove a tag at the same time...
 413                 $tagsToAdd = array_diff( $tagsToAdd, $tagsToRemove );
 414
 415                 // Update the summary row.
 416                 // $prevTags can be out of date on replica DBs, especially when addTags is called consecutively,
 417                 // causing loss of tags added recently in tag_summary table.
 418                 $prevTags = $dbw->selectField( 'tag_summary', 'ts_tags', $tsConds, __METHOD__ );
 419                 $prevTags = $prevTags ? $prevTags : '';
 420                 $prevTags = array_filter( explode( ',', $prevTags ) );
 421
 422                 // add tags
 423                 $tagsToAdd = array_values( array_diff( $tagsToAdd, $prevTags ) );
 424                 $newTags = array_unique( array_merge( $prevTags, $tagsToAdd ) );
 425
 426                 // remove tags
 427                 $tagsToRemove = array_values( array_intersect( $tagsToRemove, $newTags ) );
 428                 $newTags = array_values( array_diff( $newTags, $tagsToRemove ) );
 429
 430                 sort( $prevTags );
 431                 sort( $newTags );
 432                 if ( $prevTags == $newTags ) {
 433                         return false;
 434                 }
 435
 436                 if ( !$newTags ) {
 437                         // No tags left, so delete the row altogether
 438                         $dbw->delete( 'tag_summary', $tsConds, __METHOD__ );
 439                 } else {
 440                         // Specify the non-DEFAULT value columns in the INSERT/REPLACE clause
 441                         $row = array_filter( [ 'ts_tags' => implode( ',', $newTags ) ] + $tsConds );
 442                         // Check the unique keys for conflicts, ignoring any NULL *_id values
 443                         $uniqueKeys = [];
 444                         foreach ( [ 'ts_rev_id', 'ts_rc_id', 'ts_log_id' ] as $uniqueColumn ) {
 445                                 if ( isset( $row[$uniqueColumn] ) ) {
 446                                         $uniqueKeys[] = [ $uniqueColumn ];
 447                                 }
 448                         }
 449
 450                         $dbw->replace( 'tag_summary', $uniqueKeys, $row, __METHOD__ );
 451                 }
 452
 453                 return true;
 454         }
 455
 456         /**
 457          * Helper function to generate a fatal status with a 'not-allowed' type error.
 458          *
 459          * @param string $msgOne Message key to use in the case of one tag
 460          * @param string $msgMulti Message key to use in the case of more than one tag
 461          * @param array $tags Restricted tags (passed as $1 into the message, count of
 462          * $tags passed as $2)
 463          * @return Status
 464          * @since 1.25
 465          */
 466         protected static function restrictedTagError( $msgOne, $msgMulti, $tags ) {
 467                 $lang = RequestContext::getMain()->getLanguage();
 468                 $count = count( $tags );
 469                 return Status::newFatal( ( $count > 1 ) ? $msgMulti : $msgOne,
 470                         $lang->commaList( $tags ), $count );
 471         }
 472
 473         /**
 474          * Is it OK to allow the user to apply all the specified tags at the same time
 475          * as they edit/make the change?
 476          *
 477          * @param array $tags Tags that you are interested in applying
 478          * @param User|null $user User whose permission you wish to check, or null if
 479          * you don't care (e.g. maintenance scripts)
 480          * @return Status
 481          * @since 1.25
 482          */
 483         public static function canAddTagsAccompanyingChange( array $tags, User $user = null ) {
 484                 if ( !is_null( $user ) ) {
 485                         if ( !$user->isAllowed( 'applychangetags' ) ) {
 486                                 return Status::newFatal( 'tags-apply-no-permission' );
 487                         } elseif ( $user->isBlocked() ) {
 488                                 return Status::newFatal( 'tags-apply-blocked', $user->getName() );
 489                         }
 490                 }
 491
 492                 // to be applied, a tag has to be explicitly defined
 493                 $allowedTags = self::listExplicitlyDefinedTags();
 494                 Hooks::run( 'ChangeTagsAllowedAdd', [ &$allowedTags, $tags, $user ] );
 495                 $disallowedTags = array_diff( $tags, $allowedTags );
 496                 if ( $disallowedTags ) {
 497                         return self::restrictedTagError( 'tags-apply-not-allowed-one',
 498                                 'tags-apply-not-allowed-multi', $disallowedTags );
 499                 }
 500
 501                 return Status::newGood();
 502         }
 503
 504         /**
 505          * Adds tags to a given change, checking whether it is allowed first, but
 506          * without adding a log entry. Useful for cases where the tag is being added
 507          * along with the action that generated the change (e.g. tagging an edit as
 508          * it is being made).
 509          *
 510          * Extensions should not use this function, unless directly handling a user
 511          * request to add a particular tag. Normally, extensions should call
 512          * ChangeTags::updateTags() instead.
 513          *
 514          * @param array $tags Tags to apply
 515          * @param int|null $rc_id The rc_id of the change to add the tags to
 516          * @param int|null $rev_id The rev_id of the change to add the tags to
 517          * @param int|null $log_id The log_id of the change to add the tags to
 518          * @param string $params Params to put in the ct_params field of table
 519          * 'change_tag' when adding tags
 520          * @param User $user Who to give credit for the action
 521          * @return Status
 522          * @since 1.25
 523          */
 524         public static function addTagsAccompanyingChangeWithChecks(
 525                 array $tags, $rc_id, $rev_id, $log_id, $params, User $user
 526         ) {
 527                 // are we allowed to do this?
 528                 $result = self::canAddTagsAccompanyingChange( $tags, $user );
 529                 if ( !$result->isOK() ) {
 530                         $result->value = null;
 531                         return $result;
 532                 }
 533
 534                 // do it!
 535                 self::addTags( $tags, $rc_id, $rev_id, $log_id, $params );
 536
 537                 return Status::newGood( true );
 538         }
 539
 540         /**
 541          * Is it OK to allow the user to adds and remove the given tags tags to/from a
 542          * change?
 543          *
 544          * @param array $tagsToAdd Tags that you are interested in adding
 545          * @param array $tagsToRemove Tags that you are interested in removing
 546          * @param User|null $user User whose permission you wish to check, or null if
 547          * you don't care (e.g. maintenance scripts)
 548          * @return Status
 549          * @since 1.25
 550          */
 551         public static function canUpdateTags( array $tagsToAdd, array $tagsToRemove,
 552                 User $user = null
 553         ) {
 554                 if ( !is_null( $user ) ) {
 555                         if ( !$user->isAllowed( 'changetags' ) ) {
 556                                 return Status::newFatal( 'tags-update-no-permission' );
 557                         } elseif ( $user->isBlocked() ) {
 558                                 return Status::newFatal( 'tags-update-blocked', $user->getName() );
 559                         }
 560                 }
 561
 562                 if ( $tagsToAdd ) {
 563                         // to be added, a tag has to be explicitly defined
 564                         // @todo Allow extensions to define tags that can be applied by users...
 565                         $explicitlyDefinedTags = self::listExplicitlyDefinedTags();
 566                         $diff = array_diff( $tagsToAdd, $explicitlyDefinedTags );
 567                         if ( $diff ) {
 568                                 return self::restrictedTagError( 'tags-update-add-not-allowed-one',
 569                                         'tags-update-add-not-allowed-multi', $diff );
 570                         }
 571                 }
 572
 573                 if ( $tagsToRemove ) {
 574                         // to be removed, a tag must not be defined by an extension, or equivalently it
 575                         // has to be either explicitly defined or not defined at all
 576                         // (assuming no edge case of a tag both explicitly-defined and extension-defined)
 577                         $softwareDefinedTags = self::listSoftwareDefinedTags();
 578                         $intersect = array_intersect( $tagsToRemove, $softwareDefinedTags );
 579                         if ( $intersect ) {
 580                                 return self::restrictedTagError( 'tags-update-remove-not-allowed-one',
 581                                         'tags-update-remove-not-allowed-multi', $intersect );
 582                         }
 583                 }
 584
 585                 return Status::newGood();
 586         }
 587
 588         /**
 589          * Adds and/or removes tags to/from a given change, checking whether it is
 590          * allowed first, and adding a log entry afterwards.
 591          *
 592          * Includes a call to ChangeTag::canUpdateTags(), so your code doesn't need
 593          * to do that. However, it doesn't check whether the *_id parameters are a
 594          * valid combination. That is up to you to enforce. See ApiTag::execute() for
 595          * an example.
 596          *
 597          * @param array|null $tagsToAdd If none, pass array() or null
 598          * @param array|null $tagsToRemove If none, pass array() or null
 599          * @param int|null $rc_id The rc_id of the change to add the tags to
 600          * @param int|null $rev_id The rev_id of the change to add the tags to
 601          * @param int|null $log_id The log_id of the change to add the tags to
 602          * @param string $params Params to put in the ct_params field of table
 603          * 'change_tag' when adding tags
 604          * @param string $reason Comment for the log
 605          * @param User $user Who to give credit for the action
 606          * @return Status If successful, the value of this Status object will be an
 607          * object (stdClass) with the following fields:
 608          *  - logId: the ID of the added log entry, or null if no log entry was added
 609          *    (i.e. no operation was performed)
 610          *  - addedTags: an array containing the tags that were actually added
 611          *  - removedTags: an array containing the tags that were actually removed
 612          * @since 1.25
 613          */
 614         public static function updateTagsWithChecks( $tagsToAdd, $tagsToRemove,
 615                 $rc_id, $rev_id, $log_id, $params, $reason, User $user
 616         ) {
 617                 if ( is_null( $tagsToAdd ) ) {
 618                         $tagsToAdd = [];
 619                 }
 620                 if ( is_null( $tagsToRemove ) ) {
 621                         $tagsToRemove = [];
 622                 }
 623                 if ( !$tagsToAdd && !$tagsToRemove ) {
 624                         // no-op, don't bother
 625                         return Status::newGood( (object)[
 626                                 'logId' => null,
 627                                 'addedTags' => [],
 628                                 'removedTags' => [],
 629                         ] );
 630                 }
 631
 632                 // are we allowed to do this?
 633                 $result = self::canUpdateTags( $tagsToAdd, $tagsToRemove, $user );
 634                 if ( !$result->isOK() ) {
 635                         $result->value = null;
 636                         return $result;
 637                 }
 638
 639                 // basic rate limiting
 640                 if ( $user->pingLimiter( 'changetag' ) ) {
 641                         return Status::newFatal( 'actionthrottledtext' );
 642                 }
 643
 644                 // do it!
 645                 list( $tagsAdded, $tagsRemoved, $initialTags ) = self::updateTags( $tagsToAdd,
 646                         $tagsToRemove, $rc_id, $rev_id, $log_id, $params, null, $user );
 647                 if ( !$tagsAdded && !$tagsRemoved ) {
 648                         // no-op, don't log it
 649                         return Status::newGood( (object)[
 650                                 'logId' => null,
 651                                 'addedTags' => [],
 652                                 'removedTags' => [],
 653                         ] );
 654                 }
 655
 656                 // log it
 657                 $logEntry = new ManualLogEntry( 'tag', 'update' );
 658                 $logEntry->setPerformer( $user );
 659                 $logEntry->setComment( $reason );
 660
 661                 // find the appropriate target page
 662                 if ( $rev_id ) {
 663                         $rev = Revision::newFromId( $rev_id );
 664                         if ( $rev ) {
 665                                 $logEntry->setTarget( $rev->getTitle() );
 666                         }
 667                 } elseif ( $log_id ) {
 668                         // This function is from revision deletion logic and has nothing to do with
 669                         // change tags, but it appears to be the only other place in core where we
 670                         // perform logged actions on log items.
 671                         $logEntry->setTarget( RevDelLogList::suggestTarget( null, [ $log_id ] ) );
 672                 }
 673
 674                 if ( !$logEntry->getTarget() ) {
 675                         // target is required, so we have to set something
 676                         $logEntry->setTarget( SpecialPage::getTitleFor( 'Tags' ) );
 677                 }
 678
 679                 $logParams = [
 680                         '4::revid' => $rev_id,
 681                         '5::logid' => $log_id,
 682                         '6:list:tagsAdded' => $tagsAdded,
 683                         '7:number:tagsAddedCount' => count( $tagsAdded ),
 684                         '8:list:tagsRemoved' => $tagsRemoved,
 685                         '9:number:tagsRemovedCount' => count( $tagsRemoved ),
 686                         'initialTags' => $initialTags,
 687                 ];
 688                 $logEntry->setParameters( $logParams );
 689                 $logEntry->setRelations( [ 'Tag' => array_merge( $tagsAdded, $tagsRemoved ) ] );
 690
 691                 $dbw = wfGetDB( DB_MASTER );
 692                 $logId = $logEntry->insert( $dbw );
 693                 // Only send this to UDP, not RC, similar to patrol events
 694                 $logEntry->publish( $logId, 'udp' );
 695
 696                 return Status::newGood( (object)[
 697                         'logId' => $logId,
 698                         'addedTags' => $tagsAdded,
 699                         'removedTags' => $tagsRemoved,
 700                 ] );
 701         }
 702
 703         /**
 704          * Applies all tags-related changes to a query.
 705          * Handles selecting tags, and filtering.
 706          * Needs $tables to be set up properly, so we can figure out which join conditions to use.
 707          *
 708          * WARNING: If $filter_tag contains more than one tag, this function will add DISTINCT,
 709          * which may cause performance problems for your query unless you put the ID field of your
 710          * table at the end of the ORDER BY, and set a GROUP BY equal to the ORDER BY. For example,
 711          * if you had ORDER BY foo_timestamp DESC, you will now need GROUP BY foo_timestamp, foo_id
 712          * ORDER BY foo_timestamp DESC, foo_id DESC.
 713          *
 714          * @param string|array &$tables Table names, see Database::select
 715          * @param string|array &$fields Fields used in query, see Database::select
 716          * @param string|array &$conds Conditions used in query, see Database::select
 717          * @param array &$join_conds Join conditions, see Database::select
 718          * @param string|array &$options Options, see Database::select
 719          * @param string|array $filter_tag Tag(s) to select on
 720          *
 721          * @throws MWException When unable to determine appropriate JOIN condition for tagging
 722          */
 723         public static function modifyDisplayQuery( &$tables, &$fields, &$conds,
 724                                                                                 &$join_conds, &$options, $filter_tag = '' ) {
 725                 global $wgUseTagFilter;
 726
 727                 // Normalize to arrays
 728                 $tables = (array)$tables;
 729                 $fields = (array)$fields;
 730                 $conds = (array)$conds;
 731                 $options = (array)$options;
 732
 733                 // Figure out which ID field to use
 734                 if ( in_array( 'recentchanges', $tables ) ) {
 735                         $join_cond = 'ct_rc_id=rc_id';
 736                 } elseif ( in_array( 'logging', $tables ) ) {
 737                         $join_cond = 'ct_log_id=log_id';
 738                 } elseif ( in_array( 'revision', $tables ) ) {
 739                         $join_cond = 'ct_rev_id=rev_id';
 740                 } elseif ( in_array( 'archive', $tables ) ) {
 741                         $join_cond = 'ct_rev_id=ar_rev_id';
 742                 } else {
 743                         throw new MWException( 'Unable to determine appropriate JOIN condition for tagging.' );
 744                 }
 745
 746                 $fields['ts_tags'] = wfGetDB( DB_REPLICA )->buildGroupConcatField(
 747                         ',', 'change_tag', 'ct_tag', $join_cond
 748                 );
 749
 750                 if ( $wgUseTagFilter && $filter_tag ) {
 751                         // Somebody wants to filter on a tag.
 752                         // Add an INNER JOIN on change_tag
 753
 754                         $tables[] = 'change_tag';
 755                         $join_conds['change_tag'] = [ 'INNER JOIN', $join_cond ];
 756                         $conds['ct_tag'] = $filter_tag;
 757                         if (
 758                                 is_array( $filter_tag ) && count( $filter_tag ) > 1 &&
 759                                 !in_array( 'DISTINCT', $options )
 760                         ) {
 761                                 $options[] = 'DISTINCT';
 762                         }
 763                 }
 764         }
 765
 766         /**
 767          * Build a text box to select a change tag
 768          *
 769          * @param string $selected Tag to select by default
 770          * @param bool $ooui Use an OOUI TextInputWidget as selector instead of a non-OOUI input field
 771          *        You need to call OutputPage::enableOOUI() yourself.
 772          * @param IContextSource|null $context
 773          * @note Even though it takes null as a valid argument, an IContextSource is preferred
 774          *       in a new code, as the null value can change in the future
 775          * @return array an array of (label, selector)
 776          */
 777         public static function buildTagFilterSelector(
 778                 $selected = '', $ooui = false, IContextSource $context = null
 779         ) {
 780                 if ( !$context ) {
 781                         $context = RequestContext::getMain();
 782                 }
 783
 784                 $config = $context->getConfig();
 785                 if ( !$config->get( 'UseTagFilter' ) || !count( self::listDefinedTags() ) ) {
 786                         return [];
 787                 }
 788
 789                 $data = [
 790                         Html::rawElement(
 791                                 'label',
 792                                 [ 'for' => 'tagfilter' ],
 793                                 $context->msg( 'tag-filter' )->parse()
 794                         )
 795                 ];
 796
 797                 if ( $ooui ) {
 798                         $data[] = new OOUI\TextInputWidget( [
 799                                 'id' => 'tagfilter',
 800                                 'name' => 'tagfilter',
 801                                 'value' => $selected,
 802                                 'classes' => 'mw-tagfilter-input',
 803                         ] );
 804                 } else {
 805                         $data[] = Xml::input(
 806                                 'tagfilter',
 807                                 20,
 808                                 $selected,
 809                                 [ 'class' => 'mw-tagfilter-input mw-ui-input mw-ui-input-inline', 'id' => 'tagfilter' ]
 810                         );
 811                 }
 812
 813                 return $data;
 814         }
 815
 816         /**
 817          * Defines a tag in the valid_tag table, without checking that the tag name
 818          * is valid.
 819          * Extensions should NOT use this function; they can use the ListDefinedTags
 820          * hook instead.
 821          *
 822          * @param string $tag Tag to create
 823          * @since 1.25
 824          */
 825         public static function defineTag( $tag ) {
 826                 $dbw = wfGetDB( DB_MASTER );
 827                 $dbw->replace( 'valid_tag',
 828                         [ 'vt_tag' ],
 829                         [ 'vt_tag' => $tag ],
 830                         __METHOD__ );
 831
 832                 // clear the memcache of defined tags
 833                 self::purgeTagCacheAll();
 834         }
 835
 836         /**
 837          * Removes a tag from the valid_tag table. The tag may remain in use by
 838          * extensions, and may still show up as 'defined' if an extension is setting
 839          * it from the ListDefinedTags hook.
 840          *
 841          * @param string $tag Tag to remove
 842          * @since 1.25
 843          */
 844         public static function undefineTag( $tag ) {
 845                 $dbw = wfGetDB( DB_MASTER );
 846                 $dbw->delete( 'valid_tag', [ 'vt_tag' => $tag ], __METHOD__ );
 847
 848                 // clear the memcache of defined tags
 849                 self::purgeTagCacheAll();
 850         }
 851
 852         /**
 853          * Writes a tag action into the tag management log.
 854          *
 855          * @param string $action
 856          * @param string $tag
 857          * @param string $reason
 858          * @param User $user Who to attribute the action to
 859          * @param int $tagCount For deletion only, how many usages the tag had before
 860          * it was deleted.
 861          * @param array $logEntryTags Change tags to apply to the entry
 862          * that will be created in the tag management log
 863          * @return int ID of the inserted log entry
 864          * @since 1.25
 865          */
 866         protected static function logTagManagementAction( $action, $tag, $reason,
 867                 User $user, $tagCount = null, array $logEntryTags = []
 868         ) {
 869                 $dbw = wfGetDB( DB_MASTER );
 870
 871                 $logEntry = new ManualLogEntry( 'managetags', $action );
 872                 $logEntry->setPerformer( $user );
 873                 // target page is not relevant, but it has to be set, so we just put in
 874                 // the title of Special:Tags
 875                 $logEntry->setTarget( Title::newFromText( 'Special:Tags' ) );
 876                 $logEntry->setComment( $reason );
 877
 878                 $params = [ '4::tag' => $tag ];
 879                 if ( !is_null( $tagCount ) ) {
 880                         $params['5:number:count'] = $tagCount;
 881                 }
 882                 $logEntry->setParameters( $params );
 883                 $logEntry->setRelations( [ 'Tag' => $tag ] );
 884                 $logEntry->setTags( $logEntryTags );
 885
 886                 $logId = $logEntry->insert( $dbw );
 887                 $logEntry->publish( $logId );
 888                 return $logId;
 889         }
 890
 891         /**
 892          * Is it OK to allow the user to activate this tag?
 893          *
 894          * @param string $tag Tag that you are interested in activating
 895          * @param User|null $user User whose permission you wish to check, or null if
 896          * you don't care (e.g. maintenance scripts)
 897          * @return Status
 898          * @since 1.25
 899          */
 900         public static function canActivateTag( $tag, User $user = null ) {
 901                 if ( !is_null( $user ) ) {
 902                         if ( !$user->isAllowed( 'managechangetags' ) ) {
 903                                 return Status::newFatal( 'tags-manage-no-permission' );
 904                         } elseif ( $user->isBlocked() ) {
 905                                 return Status::newFatal( 'tags-manage-blocked', $user->getName() );
 906                         }
 907                 }
 908
 909                 // defined tags cannot be activated (a defined tag is either extension-
 910                 // defined, in which case the extension chooses whether or not to active it;
 911                 // or user-defined, in which case it is considered active)
 912                 $definedTags = self::listDefinedTags();
 913                 if ( in_array( $tag, $definedTags ) ) {
 914                         return Status::newFatal( 'tags-activate-not-allowed', $tag );
 915                 }
 916
 917                 // non-existing tags cannot be activated
 918                 $tagUsage = self::tagUsageStatistics();
 919                 if ( !isset( $tagUsage[$tag] ) ) { // we already know the tag is undefined
 920                         return Status::newFatal( 'tags-activate-not-found', $tag );
 921                 }
 922
 923                 return Status::newGood();
 924         }
 925
 926         /**
 927          * Activates a tag, checking whether it is allowed first, and adding a log
 928          * entry afterwards.
 929          *
 930          * Includes a call to ChangeTag::canActivateTag(), so your code doesn't need
 931          * to do that.
 932          *
 933          * @param string $tag
 934          * @param string $reason
 935          * @param User $user Who to give credit for the action
 936          * @param bool $ignoreWarnings Can be used for API interaction, default false
 937          * @param array $logEntryTags Change tags to apply to the entry
 938          * that will be created in the tag management log
 939          * @return Status If successful, the Status contains the ID of the added log
 940          * entry as its value
 941          * @since 1.25
 942          */
 943         public static function activateTagWithChecks( $tag, $reason, User $user,
 944                 $ignoreWarnings = false, array $logEntryTags = []
 945         ) {
 946                 // are we allowed to do this?
 947                 $result = self::canActivateTag( $tag, $user );
 948                 if ( $ignoreWarnings ? !$result->isOK() : !$result->isGood() ) {
 949                         $result->value = null;
 950                         return $result;
 951                 }
 952
 953                 // do it!
 954                 self::defineTag( $tag );
 955
 956                 // log it
 957                 $logId = self::logTagManagementAction( 'activate', $tag, $reason, $user,
 958                         null, $logEntryTags );
 959
 960                 return Status::newGood( $logId );
 961         }
 962
 963         /**
 964          * Is it OK to allow the user to deactivate this tag?
 965          *
 966          * @param string $tag Tag that you are interested in deactivating
 967          * @param User|null $user User whose permission you wish to check, or null if
 968          * you don't care (e.g. maintenance scripts)
 969          * @return Status
 970          * @since 1.25
 971          */
 972         public static function canDeactivateTag( $tag, User $user = null ) {
 973                 if ( !is_null( $user ) ) {
 974                         if ( !$user->isAllowed( 'managechangetags' ) ) {
 975                                 return Status::newFatal( 'tags-manage-no-permission' );
 976                         } elseif ( $user->isBlocked() ) {
 977                                 return Status::newFatal( 'tags-manage-blocked', $user->getName() );
 978                         }
 979                 }
 980
 981                 // only explicitly-defined tags can be deactivated
 982                 $explicitlyDefinedTags = self::listExplicitlyDefinedTags();
 983                 if ( !in_array( $tag, $explicitlyDefinedTags ) ) {
 984                         return Status::newFatal( 'tags-deactivate-not-allowed', $tag );
 985                 }
 986                 return Status::newGood();
 987         }
 988
 989         /**
 990          * Deactivates a tag, checking whether it is allowed first, and adding a log
 991          * entry afterwards.
 992          *
 993          * Includes a call to ChangeTag::canDeactivateTag(), so your code doesn't need
 994          * to do that.
 995          *
 996          * @param string $tag
 997          * @param string $reason
 998          * @param User $user Who to give credit for the action
 999          * @param bool $ignoreWarnings Can be used for API interaction, default false
1000          * @param array $logEntryTags Change tags to apply to the entry
1001          * that will be created in the tag management log
1002          * @return Status If successful, the Status contains the ID of the added log
1003          * entry as its value
1004          * @since 1.25
1005          */
1006         public static function deactivateTagWithChecks( $tag, $reason, User $user,
1007                 $ignoreWarnings = false, array $logEntryTags = []
1008         ) {
1009                 // are we allowed to do this?
1010                 $result = self::canDeactivateTag( $tag, $user );
1011                 if ( $ignoreWarnings ? !$result->isOK() : !$result->isGood() ) {
1012                         $result->value = null;
1013                         return $result;
1014                 }
1015
1016                 // do it!
1017                 self::undefineTag( $tag );
1018
1019                 // log it
1020                 $logId = self::logTagManagementAction( 'deactivate', $tag, $reason, $user,
1021                         null, $logEntryTags );
1022
1023                 return Status::newGood( $logId );
1024         }
1025
1026         /**
1027          * Is the tag name valid?
1028          *
1029          * @param string $tag Tag that you are interested in creating
1030          * @return Status
1031          * @since 1.30
1032          */
1033         public static function isTagNameValid( $tag ) {
1034                 // no empty tags
1035                 if ( $tag === '' ) {
1036                         return Status::newFatal( 'tags-create-no-name' );
1037                 }
1038
1039                 // tags cannot contain commas (used as a delimiter in tag_summary table),
1040                 // pipe (used as a delimiter between multiple tags in
1041                 // SpecialRecentchanges and friends), or slashes (would break tag description messages in
1042                 // MediaWiki namespace)
1043                 if ( strpos( $tag, ',' ) !== false || strpos( $tag, '|' ) !== false
1044                         || strpos( $tag, '/' ) !== false ) {
1045                         return Status::newFatal( 'tags-create-invalid-chars' );
1046                 }
1047
1048                 // could the MediaWiki namespace description messages be created?
1049                 $title = Title::makeTitleSafe( NS_MEDIAWIKI, "Tag-$tag-description" );
1050                 if ( is_null( $title ) ) {
1051                         return Status::newFatal( 'tags-create-invalid-title-chars' );
1052                 }
1053
1054                 return Status::newGood();
1055         }
1056
1057         /**
1058          * Is it OK to allow the user to create this tag?
1059          *
1060          * @param string $tag Tag that you are interested in creating
1061          * @param User|null $user User whose permission you wish to check, or null if
1062          * you don't care (e.g. maintenance scripts)
1063          * @return Status
1064          * @since 1.25
1065          */
1066         public static function canCreateTag( $tag, User $user = null ) {
1067                 if ( !is_null( $user ) ) {
1068                         if ( !$user->isAllowed( 'managechangetags' ) ) {
1069                                 return Status::newFatal( 'tags-manage-no-permission' );
1070                         } elseif ( $user->isBlocked() ) {
1071                                 return Status::newFatal( 'tags-manage-blocked', $user->getName() );
1072                         }
1073                 }
1074
1075                 $status = self::isTagNameValid( $tag );
1076                 if ( !$status->isGood() ) {
1077                         return $status;
1078                 }
1079
1080                 // does the tag already exist?
1081                 $tagUsage = self::tagUsageStatistics();
1082                 if ( isset( $tagUsage[$tag] ) || in_array( $tag, self::listDefinedTags() ) ) {
1083                         return Status::newFatal( 'tags-create-already-exists', $tag );
1084                 }
1085
1086                 // check with hooks
1087                 $canCreateResult = Status::newGood();
1088                 Hooks::run( 'ChangeTagCanCreate', [ $tag, $user, &$canCreateResult ] );
1089                 return $canCreateResult;
1090         }
1091
1092         /**
1093          * Creates a tag by adding a row to the `valid_tag` table.
1094          *
1095          * Includes a call to ChangeTag::canDeleteTag(), so your code doesn't need to
1096          * do that.
1097          *
1098          * @param string $tag
1099          * @param string $reason
1100          * @param User $user Who to give credit for the action
1101          * @param bool $ignoreWarnings Can be used for API interaction, default false
1102          * @param array $logEntryTags Change tags to apply to the entry
1103          * that will be created in the tag management log
1104          * @return Status If successful, the Status contains the ID of the added log
1105          * entry as its value
1106          * @since 1.25
1107          */
1108         public static function createTagWithChecks( $tag, $reason, User $user,
1109                 $ignoreWarnings = false, array $logEntryTags = []
1110         ) {
1111                 // are we allowed to do this?
1112                 $result = self::canCreateTag( $tag, $user );
1113                 if ( $ignoreWarnings ? !$result->isOK() : !$result->isGood() ) {
1114                         $result->value = null;
1115                         return $result;
1116                 }
1117
1118                 // do it!
1119                 self::defineTag( $tag );
1120
1121                 // log it
1122                 $logId = self::logTagManagementAction( 'create', $tag, $reason, $user,
1123                         null, $logEntryTags );
1124
1125                 return Status::newGood( $logId );
1126         }
1127
1128         /**
1129          * Permanently removes all traces of a tag from the DB. Good for removing
1130          * misspelt or temporary tags.
1131          *
1132          * This function should be directly called by maintenance scripts only, never
1133          * by user-facing code. See deleteTagWithChecks() for functionality that can
1134          * safely be exposed to users.
1135          *
1136          * @param string $tag Tag to remove
1137          * @return Status The returned status will be good unless a hook changed it
1138          * @since 1.25
1139          */
1140         public static function deleteTagEverywhere( $tag ) {
1141                 $dbw = wfGetDB( DB_MASTER );
1142                 $dbw->startAtomic( __METHOD__ );
1143
1144                 // delete from valid_tag
1145                 self::undefineTag( $tag );
1146
1147                 // find out which revisions use this tag, so we can delete from tag_summary
1148                 $result = $dbw->select( 'change_tag',
1149                         [ 'ct_rc_id', 'ct_log_id', 'ct_rev_id', 'ct_tag' ],
1150                         [ 'ct_tag' => $tag ],
1151                         __METHOD__ );
1152                 foreach ( $result as $row ) {
1153                         // remove the tag from the relevant row of tag_summary
1154                         $tagsToAdd = [];
1155                         $tagsToRemove = [ $tag ];
1156                         self::updateTagSummaryRow( $tagsToAdd, $tagsToRemove, $row->ct_rc_id,
1157                                 $row->ct_rev_id, $row->ct_log_id );
1158                 }
1159
1160                 // delete from change_tag
1161                 $dbw->delete( 'change_tag', [ 'ct_tag' => $tag ], __METHOD__ );
1162
1163                 $dbw->endAtomic( __METHOD__ );
1164
1165                 // give extensions a chance
1166                 $status = Status::newGood();
1167                 Hooks::run( 'ChangeTagAfterDelete', [ $tag, &$status ] );
1168                 // let's not allow error results, as the actual tag deletion succeeded
1169                 if ( !$status->isOK() ) {
1170                         wfDebug( 'ChangeTagAfterDelete error condition downgraded to warning' );
1171                         $status->setOK( true );
1172                 }
1173
1174                 // clear the memcache of defined tags
1175                 self::purgeTagCacheAll();
1176
1177                 return $status;
1178         }
1179
1180         /**
1181          * Is it OK to allow the user to delete this tag?
1182          *
1183          * @param string $tag Tag that you are interested in deleting
1184          * @param User|null $user User whose permission you wish to check, or null if
1185          * you don't care (e.g. maintenance scripts)
1186          * @return Status
1187          * @since 1.25
1188          */
1189         public static function canDeleteTag( $tag, User $user = null ) {
1190                 $tagUsage = self::tagUsageStatistics();
1191
1192                 if ( !is_null( $user ) ) {
1193                         if ( !$user->isAllowed( 'deletechangetags' ) ) {
1194                                 return Status::newFatal( 'tags-delete-no-permission' );
1195                         } elseif ( $user->isBlocked() ) {
1196                                 return Status::newFatal( 'tags-manage-blocked', $user->getName() );
1197                         }
1198                 }
1199
1200                 if ( !isset( $tagUsage[$tag] ) && !in_array( $tag, self::listDefinedTags() ) ) {
1201                         return Status::newFatal( 'tags-delete-not-found', $tag );
1202                 }
1203
1204                 if ( isset( $tagUsage[$tag] ) && $tagUsage[$tag] > self::MAX_DELETE_USES ) {
1205                         return Status::newFatal( 'tags-delete-too-many-uses', $tag, self::MAX_DELETE_USES );
1206                 }
1207
1208                 $softwareDefined = self::listSoftwareDefinedTags();
1209                 if ( in_array( $tag, $softwareDefined ) ) {
1210                         // extension-defined tags can't be deleted unless the extension
1211                         // specifically allows it
1212                         $status = Status::newFatal( 'tags-delete-not-allowed' );
1213                 } else {
1214                         // user-defined tags are deletable unless otherwise specified
1215                         $status = Status::newGood();
1216                 }
1217
1218                 Hooks::run( 'ChangeTagCanDelete', [ $tag, $user, &$status ] );
1219                 return $status;
1220         }
1221
1222         /**
1223          * Deletes a tag, checking whether it is allowed first, and adding a log entry
1224          * afterwards.
1225          *
1226          * Includes a call to ChangeTag::canDeleteTag(), so your code doesn't need to
1227          * do that.
1228          *
1229          * @param string $tag
1230          * @param string $reason
1231          * @param User $user Who to give credit for the action
1232          * @param bool $ignoreWarnings Can be used for API interaction, default false
1233          * @param array $logEntryTags Change tags to apply to the entry
1234          * that will be created in the tag management log
1235          * @return Status If successful, the Status contains the ID of the added log
1236          * entry as its value
1237          * @since 1.25
1238          */
1239         public static function deleteTagWithChecks( $tag, $reason, User $user,
1240                 $ignoreWarnings = false, array $logEntryTags = []
1241         ) {
1242                 // are we allowed to do this?
1243                 $result = self::canDeleteTag( $tag, $user );
1244                 if ( $ignoreWarnings ? !$result->isOK() : !$result->isGood() ) {
1245                         $result->value = null;
1246                         return $result;
1247                 }
1248
1249                 // store the tag usage statistics
1250                 $tagUsage = self::tagUsageStatistics();
1251                 $hitcount = isset( $tagUsage[$tag] ) ? $tagUsage[$tag] : 0;
1252
1253                 // do it!
1254                 $deleteResult = self::deleteTagEverywhere( $tag );
1255                 if ( !$deleteResult->isOK() ) {
1256                         return $deleteResult;
1257                 }
1258
1259                 // log it
1260                 $logId = self::logTagManagementAction( 'delete', $tag, $reason, $user,
1261                         $hitcount, $logEntryTags );
1262
1263                 $deleteResult->value = $logId;
1264                 return $deleteResult;
1265         }
1266
1267         /**
1268          * Lists those tags which core or extensions report as being "active".
1269          *
1270          * @return array
1271          * @since 1.25
1272          */
1273         public static function listSoftwareActivatedTags() {
1274                 // core active tags
1275                 $tags = self::getSoftwareTags();
1276                 if ( !Hooks::isRegistered( 'ChangeTagsListActive' ) ) {
1277                         return $tags;
1278                 }
1279                 $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
1280                 return $cache->getWithSetCallback(
1281                         $cache->makeKey( 'active-tags' ),
1282                         WANObjectCache::TTL_MINUTE * 5,
1283                         function ( $oldValue, &$ttl, array &$setOpts ) use ( $tags ) {
1284                                 $setOpts += Database::getCacheSetOptions( wfGetDB( DB_REPLICA ) );
1285
1286                                 // Ask extensions which tags they consider active
1287                                 Hooks::run( 'ChangeTagsListActive', [ &$tags ] );
1288                                 return $tags;
1289                         },
1290                         [
1291                                 'checkKeys' => [ $cache->makeKey( 'active-tags' ) ],
1292                                 'lockTSE' => WANObjectCache::TTL_MINUTE * 5,
1293                                 'pcTTL' => WANObjectCache::TTL_PROC_LONG
1294                         ]
1295                 );
1296         }
1297
1298         /**
1299          * @see listSoftwareActivatedTags
1300          * @deprecated since 1.28 call listSoftwareActivatedTags directly
1301          * @return array
1302          */
1303         public static function listExtensionActivatedTags() {
1304                 wfDeprecated( __METHOD__, '1.28' );
1305                 return self::listSoftwareActivatedTags();
1306         }
1307
1308         /**
1309          * Basically lists defined tags which count even if they aren't applied to anything.
1310          * It returns a union of the results of listExplicitlyDefinedTags() and
1311          * listExtensionDefinedTags().
1312          *
1313          * @return string[] Array of strings: tags
1314          */
1315         public static function listDefinedTags() {
1316                 $tags1 = self::listExplicitlyDefinedTags();
1317                 $tags2 = self::listSoftwareDefinedTags();
1318                 return array_values( array_unique( array_merge( $tags1, $tags2 ) ) );
1319         }
1320
1321         /**
1322          * Lists tags explicitly defined in the `valid_tag` table of the database.
1323          * Tags in table 'change_tag' which are not in table 'valid_tag' are not
1324          * included.
1325          *
1326          * Tries memcached first.
1327          *
1328          * @return string[] Array of strings: tags
1329          * @since 1.25
1330          */
1331         public static function listExplicitlyDefinedTags() {
1332                 $fname = __METHOD__;
1333
1334                 $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
1335                 return $cache->getWithSetCallback(
1336                         $cache->makeKey( 'valid-tags-db' ),
1337                         WANObjectCache::TTL_MINUTE * 5,
1338                         function ( $oldValue, &$ttl, array &$setOpts ) use ( $fname ) {
1339                                 $dbr = wfGetDB( DB_REPLICA );
1340
1341                                 $setOpts += Database::getCacheSetOptions( $dbr );
1342
1343                                 $tags = $dbr->selectFieldValues( 'valid_tag', 'vt_tag', [], $fname );
1344
1345                                 return array_filter( array_unique( $tags ) );
1346                         },
1347                         [
1348                                 'checkKeys' => [ $cache->makeKey( 'valid-tags-db' ) ],
1349                                 'lockTSE' => WANObjectCache::TTL_MINUTE * 5,
1350                                 'pcTTL' => WANObjectCache::TTL_PROC_LONG
1351                         ]
1352                 );
1353         }
1354
1355         /**
1356          * Lists tags defined by core or extensions using the ListDefinedTags hook.
1357          * Extensions need only define those tags they deem to be in active use.
1358          *
1359          * Tries memcached first.
1360          *
1361          * @return string[] Array of strings: tags
1362          * @since 1.25
1363          */
1364         public static function listSoftwareDefinedTags() {
1365                 // core defined tags
1366                 $tags = self::getSoftwareTags( true );
1367                 if ( !Hooks::isRegistered( 'ListDefinedTags' ) ) {
1368                         return $tags;
1369                 }
1370                 $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
1371                 return $cache->getWithSetCallback(
1372                         $cache->makeKey( 'valid-tags-hook' ),
1373                         WANObjectCache::TTL_MINUTE * 5,
1374                         function ( $oldValue, &$ttl, array &$setOpts ) use ( $tags ) {
1375                                 $setOpts += Database::getCacheSetOptions( wfGetDB( DB_REPLICA ) );
1376
1377                                 Hooks::run( 'ListDefinedTags', [ &$tags ] );
1378                                 return array_filter( array_unique( $tags ) );
1379                         },
1380                         [
1381                                 'checkKeys' => [ $cache->makeKey( 'valid-tags-hook' ) ],
1382                                 'lockTSE' => WANObjectCache::TTL_MINUTE * 5,
1383                                 'pcTTL' => WANObjectCache::TTL_PROC_LONG
1384                         ]
1385                 );
1386         }
1387
1388         /**
1389          * Call listSoftwareDefinedTags directly
1390          *
1391          * @see listSoftwareDefinedTags
1392          * @deprecated since 1.28
1393          * @return array
1394          */
1395         public static function listExtensionDefinedTags() {
1396                 wfDeprecated( __METHOD__, '1.28' );
1397                 return self::listSoftwareDefinedTags();
1398         }
1399
1400         /**
1401          * Invalidates the short-term cache of defined tags used by the
1402          * list*DefinedTags functions, as well as the tag statistics cache.
1403          * @since 1.25
1404          */
1405         public static function purgeTagCacheAll() {
1406                 $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
1407
1408                 $cache->touchCheckKey( $cache->makeKey( 'active-tags' ) );
1409                 $cache->touchCheckKey( $cache->makeKey( 'valid-tags-db' ) );
1410                 $cache->touchCheckKey( $cache->makeKey( 'valid-tags-hook' ) );
1411
1412                 self::purgeTagUsageCache();
1413         }
1414
1415         /**
1416          * Invalidates the tag statistics cache only.
1417          * @since 1.25
1418          */
1419         public static function purgeTagUsageCache() {
1420                 $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
1421
1422                 $cache->touchCheckKey( $cache->makeKey( 'change-tag-statistics' ) );
1423         }
1424
1425         /**
1426          * Returns a map of any tags used on the wiki to number of edits
1427          * tagged with them, ordered descending by the hitcount.
1428          * This does not include tags defined somewhere that have never been applied.
1429          *
1430          * Keeps a short-term cache in memory, so calling this multiple times in the
1431          * same request should be fine.
1432          *
1433          * @return array Array of string => int
1434          */
1435         public static function tagUsageStatistics() {
1436                 $fname = __METHOD__;
1437                 $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
1438                 return $cache->getWithSetCallback(
1439                         $cache->makeKey( 'change-tag-statistics' ),
1440                         WANObjectCache::TTL_MINUTE * 5,
1441                         function ( $oldValue, &$ttl, array &$setOpts ) use ( $fname ) {
1442                                 $dbr = wfGetDB( DB_REPLICA, 'vslow' );
1443
1444                                 $setOpts += Database::getCacheSetOptions( $dbr );
1445
1446                                 $res = $dbr->select(
1447                                         'change_tag',
1448                                         [ 'ct_tag', 'hitcount' => 'count(*)' ],
1449                                         [],
1450                                         $fname,
1451                                         [ 'GROUP BY' => 'ct_tag', 'ORDER BY' => 'hitcount DESC' ]
1452                                 );
1453
1454                                 $out = [];
1455                                 foreach ( $res as $row ) {
1456                                         $out[$row->ct_tag] = $row->hitcount;
1457                                 }
1458
1459                                 return $out;
1460                         },
1461                         [
1462                                 'checkKeys' => [ $cache->makeKey( 'change-tag-statistics' ) ],
1463                                 'lockTSE' => WANObjectCache::TTL_MINUTE * 5,
1464                                 'pcTTL' => WANObjectCache::TTL_PROC_LONG
1465                         ]
1466                 );
1467         }
1468
1469         /**
1470          * Indicate whether change tag editing UI is relevant
1471          *
1472          * Returns true if the user has the necessary right and there are any
1473          * editable tags defined.
1474          *
1475          * This intentionally doesn't check "any addable || any deletable", because
1476          * it seems like it would be more confusing than useful if the checkboxes
1477          * suddenly showed up because some abuse filter stopped defining a tag and
1478          * then suddenly disappeared when someone deleted all uses of that tag.
1479          *
1480          * @param User $user
1481          * @return bool
1482          */
1483         public static function showTagEditingUI( User $user ) {
1484                 return $user->isAllowed( 'changetags' ) && (bool)self::listExplicitlyDefinedTags();
1485         }
1486 }