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