includes/changetags/ChangeTags.php

   1 <?php
   2 /**
   3  * Recent changes tagging.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  * @ingroup Change tagging
  22  */
  23
  24 use MediaWiki\MediaWikiServices;
  25 use MediaWiki\Storage\NameTableAccessException;
  26 use Wikimedia\Rdbms\Database;
  27
  28 class ChangeTags {
  29         /**
  30          * Can't delete tags with more than this many uses. Similar in intent to
  31          * the bigdelete user right
  32          * @todo Use the job queue for tag deletion to avoid this restriction
  33          */
  34         const MAX_DELETE_USES = 5000;
  35
  36         /**
  37          * A list of tags defined and used by MediaWiki itself.
  38          */
  39         private static $definedSoftwareTags = [
  40                 'mw-contentmodelchange',
  41                 'mw-new-redirect',
  42                 'mw-removed-redirect',
  43                 'mw-changed-redirect-target',
  44                 'mw-blank',
  45                 'mw-replace',
  46                 'mw-rollback',
  47                 'mw-undo',
  48         ];
  49
  50         /**
  51          * Loads defined core tags, checks for invalid types (if not array),
  52          * and filters for supported and enabled (if $all is false) tags only.
  53          *
  54          * @param bool $all If true, return all valid defined tags. Otherwise, return only enabled ones.
  55          * @return array Array of all defined/enabled tags.
  56          */
  57         public static function getSoftwareTags( $all = false ) {
  58                 global $wgSoftwareTags;
  59                 $softwareTags = [];
  60
  61                 if ( !is_array( $wgSoftwareTags ) ) {
  62                         wfWarn( 'wgSoftwareTags should be associative array of enabled tags.
  63                         Please refer to documentation for the list of tags you can enable' );
  64                         return $softwareTags;
  65                 }
  66
  67                 $availableSoftwareTags = !$all ?
  68                         array_keys( array_filter( $wgSoftwareTags ) ) :
  69                         array_keys( $wgSoftwareTags );
  70
  71                 $softwareTags = array_intersect(
  72                         $availableSoftwareTags,
  73                         self::$definedSoftwareTags
  74                 );
  75
  76                 return $softwareTags;
  77         }
  78
  79         /**
  80          * Creates HTML for the given tags
  81          *
  82          * @param string $tags Comma-separated list of tags
  83          * @param string $page A label for the type of action which is being displayed,
  84          *   for example: 'history', 'contributions' or 'newpages'
  85          * @param IContextSource|null $context
  86          * @note Even though it takes null as a valid argument, an IContextSource is preferred
  87          *       in a new code, as the null value is subject to change in the future
  88          * @return array Array with two items: (html, classes)
  89          *   - html: String: HTML for displaying the tags (empty string when param $tags is empty)
  90          *   - classes: Array of strings: CSS classes used in the generated html, one class for each tag
  91          * @return-taint onlysafefor_htmlnoent
  92          */
  93         public static function formatSummaryRow( $tags, $page, IContextSource $context = null ) {
  94                 if ( !$tags ) {
  95                         return [ '', [] ];
  96                 }
  97                 if ( !$context ) {
  98                         $context = RequestContext::getMain();
  99                 }
 100
 101                 $classes = [];
 102
 103                 $tags = explode( ',', $tags );
 104                 $displayTags = [];
 105                 foreach ( $tags as $tag ) {
 106                         if ( !$tag ) {
 107                                 continue;
 108                         }
 109                         $description = self::tagDescription( $tag, $context );
 110                         if ( $description === false ) {
 111                                 continue;
 112                         }
 113                         $displayTags[] = Xml::tags(
 114                                 'span',
 115                                 [ 'class' => 'mw-tag-marker ' .
 116                                                                 Sanitizer::escapeClass( "mw-tag-marker-$tag" ) ],
 117                                 $description
 118                         );
 119                         $classes[] = Sanitizer::escapeClass( "mw-tag-$tag" );
 120                 }
 121
 122                 if ( !$displayTags ) {
 123                         return [ '', [] ];
 124                 }
 125
 126                 $markers = $context->msg( 'tag-list-wrapper' )
 127                         ->numParams( count( $displayTags ) )
 128                         ->rawParams( $context->getLanguage()->commaList( $displayTags ) )
 129                         ->parse();
 130                 $markers = Xml::tags( 'span', [ 'class' => 'mw-tag-markers' ], $markers );
 131
 132                 return [ $markers, $classes ];
 133         }
 134
 135         /**
 136          * Get a short description for a tag.
 137          *
 138          * Checks if message key "mediawiki:tag-$tag" exists. If it does not,
 139          * returns the HTML-escaped tag name. Uses the message if the message
 140          * exists, provided it is not disabled. If the message is disabled,
 141          * we consider the tag hidden, and return false.
 142          *
 143          * @param string $tag
 144          * @param IContextSource $context
 145          * @return string|bool Tag description or false if tag is to be hidden.
 146          * @since 1.25 Returns false if tag is to be hidden.
 147          */
 148         public static function tagDescription( $tag, IContextSource $context ) {
 149                 $msg = $context->msg( "tag-$tag" );
 150                 if ( !$msg->exists() ) {
 151                         // No such message, so return the HTML-escaped tag name.
 152                         return htmlspecialchars( $tag );
 153                 }
 154                 if ( $msg->isDisabled() ) {
 155                         // The message exists but is disabled, hide the tag.
 156                         return false;
 157                 }
 158
 159                 // Message exists and isn't disabled, use it.
 160                 return $msg->parse();
 161         }
 162
 163         /**
 164          * Get the message object for the tag's long description.
 165          *
 166          * Checks if message key "mediawiki:tag-$tag-description" exists. If it does not,
 167          * or if message is disabled, returns false. Otherwise, returns the message object
 168          * for the long description.
 169          *
 170          * @param string $tag
 171          * @param IContextSource $context
 172          * @return Message|bool Message object of the tag long description or false if
 173          *  there is no description.
 174          */
 175         public static function tagLongDescriptionMessage( $tag, IContextSource $context ) {
 176                 $msg = $context->msg( "tag-$tag-description" );
 177                 if ( !$msg->exists() ) {
 178                         return false;
 179                 }
 180                 if ( $msg->isDisabled() ) {
 181                         // The message exists but is disabled, hide the description.
 182                         return false;
 183                 }
 184
 185                 // Message exists and isn't disabled, use it.
 186                 return $msg;
 187         }
 188
 189         /**
 190          * Get truncated message for the tag's long description.
 191          *
 192          * @param string $tag Tag name.
 193          * @param int $length Maximum length of truncated message, including ellipsis.
 194          * @param IContextSource $context
 195          *
 196          * @return string Truncated long tag description.
 197          */
 198         public static function truncateTagDescription( $tag, $length, IContextSource $context ) {
 199                 $originalDesc = self::tagLongDescriptionMessage( $tag, $context );
 200                 // If there is no tag description, return empty string
 201                 if ( !$originalDesc ) {
 202                         return '';
 203                 }
 204
 205                 $taglessDesc = Sanitizer::stripAllTags( $originalDesc->parse() );
 206
 207                 return $context->getLanguage()->truncateForVisual( $taglessDesc, $length );
 208         }
 209
 210         /**
 211          * Add tags to a change given its rc_id, rev_id and/or log_id
 212          *
 213          * @param string|string[] $tags Tags to add to the change
 214          * @param int|null $rc_id The rc_id of the change to add the tags to
 215          * @param int|null $rev_id The rev_id of the change to add the tags to
 216          * @param int|null $log_id The log_id of the change to add the tags to
 217          * @param string|null $params Params to put in the ct_params field of table 'change_tag'
 218          * @param RecentChange|null $rc Recent change, in case the tagging accompanies the action
 219          * (this should normally be the case)
 220          *
 221          * @throws MWException
 222          * @return bool False if no changes are made, otherwise true
 223          */
 224         public static function addTags( $tags, $rc_id = null, $rev_id = null,
 225                 $log_id = null, $params = null, RecentChange $rc = null
 226         ) {
 227                 $result = self::updateTags( $tags, null, $rc_id, $rev_id, $log_id, $params, $rc );
 228                 return (bool)$result[0];
 229         }
 230
 231         /**
 232          * Add and remove tags to/from a change given its rc_id, rev_id and/or log_id,
 233          * without verifying that the tags exist or are valid. If a tag is present in
 234          * both $tagsToAdd and $tagsToRemove, it will be removed.
 235          *
 236          * This function should only be used by extensions to manipulate tags they
 237          * have registered using the ListDefinedTags hook. When dealing with user
 238          * input, call updateTagsWithChecks() instead.
 239          *
 240          * @param string|array|null $tagsToAdd Tags to add to the change
 241          * @param string|array|null $tagsToRemove Tags to remove from the change
 242          * @param int|null &$rc_id The rc_id of the change to add the tags to.
 243          * Pass a variable whose value is null if the rc_id is not relevant or unknown.
 244          * @param int|null &$rev_id The rev_id of the change to add the tags to.
 245          * Pass a variable whose value is null if the rev_id is not relevant or unknown.
 246          * @param int|null &$log_id The log_id of the change to add the tags to.
 247          * Pass a variable whose value is null if the log_id is not relevant or unknown.
 248          * @param string|null $params Params to put in the ct_params field of table
 249          * 'change_tag' when adding tags
 250          * @param RecentChange|null $rc Recent change being tagged, in case the tagging accompanies
 251          * the action
 252          * @param User|null $user Tagging user, in case the tagging is subsequent to the tagged action
 253          *
 254          * @throws MWException When $rc_id, $rev_id and $log_id are all null
 255          * @return array Index 0 is an array of tags actually added, index 1 is an
 256          * array of tags actually removed, index 2 is an array of tags present on the
 257          * revision or log entry before any changes were made
 258          *
 259          * @since 1.25
 260          */
 261         public static function updateTags( $tagsToAdd, $tagsToRemove, &$rc_id = null,
 262                 &$rev_id = null, &$log_id = null, $params = null, RecentChange $rc = null,
 263                 User $user = null
 264         ) {
 265                 $tagsToAdd = array_filter( (array)$tagsToAdd ); // Make sure we're submitting all tags...
 266                 $tagsToRemove = array_filter( (array)$tagsToRemove );
 267
 268                 if ( !$rc_id && !$rev_id && !$log_id ) {
 269                         throw new MWException( 'At least one of: RCID, revision ID, and log ID MUST be ' .
 270                                 'specified when adding or removing a tag from a change!' );
 271                 }
 272
 273                 $dbw = wfGetDB( DB_MASTER );
 274
 275                 // Might as well look for rcids and so on.
 276                 if ( !$rc_id ) {
 277                         // Info might be out of date, somewhat fractionally, on replica DB.
 278                         // LogEntry/LogPage and WikiPage match rev/log/rc timestamps,
 279                         // so use that relation to avoid full table scans.
 280                         if ( $log_id ) {
 281                                 $rc_id = $dbw->selectField(
 282                                         [ 'logging', 'recentchanges' ],
 283                                         'rc_id',
 284                                         [
 285                                                 'log_id' => $log_id,
 286                                                 'rc_timestamp = log_timestamp',
 287                                                 'rc_logid = log_id'
 288                                         ],
 289                                         __METHOD__
 290                                 );
 291                         } elseif ( $rev_id ) {
 292                                 $rc_id = $dbw->selectField(
 293                                         [ 'revision', 'recentchanges' ],
 294                                         'rc_id',
 295                                         [
 296                                                 'rev_id' => $rev_id,
 297                                                 'rc_timestamp = rev_timestamp',
 298                                                 'rc_this_oldid = rev_id'
 299                                         ],
 300                                         __METHOD__
 301                                 );
 302                         }
 303                 } elseif ( !$log_id && !$rev_id ) {
 304                         // Info might be out of date, somewhat fractionally, on replica DB.
 305                         $log_id = $dbw->selectField(
 306                                 'recentchanges',
 307                                 'rc_logid',
 308                                 [ 'rc_id' => $rc_id ],
 309                                 __METHOD__
 310                         );
 311                         $rev_id = $dbw->selectField(
 312                                 'recentchanges',
 313                                 'rc_this_oldid',
 314                                 [ 'rc_id' => $rc_id ],
 315                                 __METHOD__
 316                         );
 317                 }
 318
 319                 if ( $log_id && !$rev_id ) {
 320                         $rev_id = $dbw->selectField(
 321                                 'log_search',
 322                                 'ls_value',
 323                                 [ 'ls_field' => 'associated_rev_id', 'ls_log_id' => $log_id ],
 324                                 __METHOD__
 325                         );
 326                 } elseif ( !$log_id && $rev_id ) {
 327                         $log_id = $dbw->selectField(
 328                                 'log_search',
 329                                 'ls_log_id',
 330                                 [ 'ls_field' => 'associated_rev_id', 'ls_value' => $rev_id ],
 331                                 __METHOD__
 332                         );
 333                 }
 334
 335                 // update the tag_summary row
 336                 $prevTags = [];
 337                 if ( !self::updateTagSummaryRow( $tagsToAdd, $tagsToRemove, $rc_id, $rev_id,
 338                         $log_id, $prevTags )
 339                 ) {
 340                         // nothing to do
 341                         return [ [], [], $prevTags ];
 342                 }
 343
 344                 // insert a row into change_tag for each new tag
 345                 $changeTagDefStore = MediaWikiServices::getInstance()->getChangeTagDefStore();
 346                 if ( count( $tagsToAdd ) ) {
 347                         $changeTagMapping = [];
 348                         foreach ( $tagsToAdd as $tag ) {
 349                                 $changeTagMapping[$tag] = $changeTagDefStore->acquireId( $tag );
 350                         }
 351                         $fname = __METHOD__;
 352                         // T207881: update the counts at the end of the transaction
 353                         $dbw->onTransactionPreCommitOrIdle( function () use ( $dbw, $tagsToAdd, $fname ) {
 354                                 $dbw->update(
 355                                         'change_tag_def',
 356                                         [ 'ctd_count = ctd_count + 1' ],
 357                                         [ 'ctd_name' => $tagsToAdd ],
 358                                         $fname
 359                                 );
 360                         } );
 361
 362                         $tagsRows = [];
 363                         foreach ( $tagsToAdd as $tag ) {
 364                                 // Filter so we don't insert NULLs as zero accidentally.
 365                                 // Keep in mind that $rc_id === null means "I don't care/know about the
 366                                 // rc_id, just delete $tag on this revision/log entry". It doesn't
 367                                 // mean "only delete tags on this revision/log WHERE rc_id IS NULL".
 368                                 $tagsRows[] = array_filter(
 369                                         [
 370                                                 'ct_rc_id' => $rc_id,
 371                                                 'ct_log_id' => $log_id,
 372                                                 'ct_rev_id' => $rev_id,
 373                                                 'ct_params' => $params,
 374                                                 'ct_tag_id' => $changeTagMapping[$tag] ?? null,
 375                                         ]
 376                                 );
 377
 378                         }
 379
 380                         $dbw->insert( 'change_tag', $tagsRows, __METHOD__, [ 'IGNORE' ] );
 381                 }
 382
 383                 // delete from change_tag
 384                 if ( count( $tagsToRemove ) ) {
 385                         $fname = __METHOD__;
 386                         foreach ( $tagsToRemove as $tag ) {
 387                                 $conds = array_filter(
 388                                         [
 389                                                 'ct_rc_id' => $rc_id,
 390                                                 'ct_log_id' => $log_id,
 391                                                 'ct_rev_id' => $rev_id,
 392                                                 'ct_tag_id' => $changeTagDefStore->getId( $tag ),
 393                                         ]
 394                                 );
 395                                 $dbw->delete( 'change_tag', $conds, __METHOD__ );
 396                                 if ( $dbw->affectedRows() ) {
 397                                         // T207881: update the counts at the end of the transaction
 398                                         $dbw->onTransactionPreCommitOrIdle( function () use ( $dbw, $tag, $fname ) {
 399                                                 $dbw->update(
 400                                                         'change_tag_def',
 401                                                         [ 'ctd_count = ctd_count - 1' ],
 402                                                         [ 'ctd_name' => $tag ],
 403                                                         $fname
 404                                                 );
 405
 406                                                 $dbw->delete(
 407                                                         'change_tag_def',
 408                                                         [ 'ctd_name' => $tag, 'ctd_count' => 0, 'ctd_user_defined' => 0 ],
 409                                                         $fname
 410                                                 );
 411                                         } );
 412                                 }
 413                         }
 414                 }
 415
 416                 self::purgeTagUsageCache();
 417
 418                 Hooks::run( 'ChangeTagsAfterUpdateTags', [ $tagsToAdd, $tagsToRemove, $prevTags,
 419                         $rc_id, $rev_id, $log_id, $params, $rc, $user ] );
 420
 421                 return [ $tagsToAdd, $tagsToRemove, $prevTags ];
 422         }
 423
 424         /**
 425          * Adds or removes a given set of tags to/from the relevant row of the
 426          * tag_summary table. Modifies the tagsToAdd and tagsToRemove arrays to
 427          * reflect the tags that were actually added and/or removed.
 428          *
 429          * @param array &$tagsToAdd
 430          * @param array &$tagsToRemove If a tag is present in both $tagsToAdd and
 431          * $tagsToRemove, it will be removed
 432          * @param int|null $rc_id Null if not known or not applicable
 433          * @param int|null $rev_id Null if not known or not applicable
 434          * @param int|null $log_id Null if not known or not applicable
 435          * @param array &$prevTags Optionally outputs a list of the tags that were
 436          * in the tag_summary row to begin with
 437          * @return bool True if any modifications were made, otherwise false
 438          * @since 1.25
 439          */
 440         protected static function updateTagSummaryRow( &$tagsToAdd, &$tagsToRemove,
 441                 $rc_id, $rev_id, $log_id, &$prevTags = []
 442         ) {
 443                 $dbw = wfGetDB( DB_MASTER );
 444
 445                 $tsConds = array_filter( [
 446                         'ts_rc_id' => $rc_id,
 447                         'ts_rev_id' => $rev_id,
 448                         'ts_log_id' => $log_id
 449                 ] );
 450
 451                 // Can't both add and remove a tag at the same time...
 452                 $tagsToAdd = array_diff( $tagsToAdd, $tagsToRemove );
 453
 454                 // Update the summary row.
 455                 // $prevTags can be out of date on replica DBs, especially when addTags is called consecutively,
 456                 // causing loss of tags added recently in tag_summary table.
 457                 $prevTags = $dbw->selectField( 'tag_summary', 'ts_tags', $tsConds, __METHOD__ );
 458                 $prevTags = $prevTags ?: '';
 459                 $prevTags = array_filter( explode( ',', $prevTags ) );
 460
 461                 // add tags
 462                 $tagsToAdd = array_values( array_diff( $tagsToAdd, $prevTags ) );
 463                 $newTags = array_unique( array_merge( $prevTags, $tagsToAdd ) );
 464
 465                 // remove tags
 466                 $tagsToRemove = array_values( array_intersect( $tagsToRemove, $newTags ) );
 467                 $newTags = array_values( array_diff( $newTags, $tagsToRemove ) );
 468
 469                 sort( $prevTags );
 470                 sort( $newTags );
 471                 if ( $prevTags == $newTags ) {
 472                         return false;
 473                 }
 474
 475                 if ( !$newTags ) {
 476                         // No tags left, so delete the row altogether
 477                         $dbw->delete( 'tag_summary', $tsConds, __METHOD__ );
 478                 } else {
 479                         // Specify the non-DEFAULT value columns in the INSERT/REPLACE clause
 480                         $row = array_filter( [ 'ts_tags' => implode( ',', $newTags ) ] + $tsConds );
 481                         // Check the unique keys for conflicts, ignoring any NULL *_id values
 482                         $uniqueKeys = [];
 483                         foreach ( [ 'ts_rev_id', 'ts_rc_id', 'ts_log_id' ] as $uniqueColumn ) {
 484                                 if ( isset( $row[$uniqueColumn] ) ) {
 485                                         $uniqueKeys[] = [ $uniqueColumn ];
 486                                 }
 487                         }
 488
 489                         $dbw->replace( 'tag_summary', $uniqueKeys, $row, __METHOD__ );
 490                 }
 491
 492                 return true;
 493         }
 494
 495         /**
 496          * Helper function to generate a fatal status with a 'not-allowed' type error.
 497          *
 498          * @param string $msgOne Message key to use in the case of one tag
 499          * @param string $msgMulti Message key to use in the case of more than one tag
 500          * @param array $tags Restricted tags (passed as $1 into the message, count of
 501          * $tags passed as $2)
 502          * @return Status
 503          * @since 1.25
 504          */
 505         protected static function restrictedTagError( $msgOne, $msgMulti, $tags ) {
 506                 $lang = RequestContext::getMain()->getLanguage();
 507                 $count = count( $tags );
 508                 return Status::newFatal( ( $count > 1 ) ? $msgMulti : $msgOne,
 509                         $lang->commaList( $tags ), $count );
 510         }
 511
 512         /**
 513          * Is it OK to allow the user to apply all the specified tags at the same time
 514          * as they edit/make the change?
 515          *
 516          * Extensions should not use this function, unless directly handling a user
 517          * request to add a tag to a revision or log entry that the user is making.
 518          *
 519          * @param array $tags Tags that you are interested in applying
 520          * @param User|null $user User whose permission you wish to check, or null to
 521          * check for a generic non-blocked user with the relevant rights
 522          * @return Status
 523          * @since 1.25
 524          */
 525         public static function canAddTagsAccompanyingChange( array $tags, User $user = null ) {
 526                 if ( !is_null( $user ) ) {
 527                         if ( !$user->isAllowed( 'applychangetags' ) ) {
 528                                 return Status::newFatal( 'tags-apply-no-permission' );
 529                         } elseif ( $user->isBlocked() ) {
 530                                 return Status::newFatal( 'tags-apply-blocked', $user->getName() );
 531                         }
 532                 }
 533
 534                 // to be applied, a tag has to be explicitly defined
 535                 $allowedTags = self::listExplicitlyDefinedTags();
 536                 Hooks::run( 'ChangeTagsAllowedAdd', [ &$allowedTags, $tags, $user ] );
 537                 $disallowedTags = array_diff( $tags, $allowedTags );
 538                 if ( $disallowedTags ) {
 539                         return self::restrictedTagError( 'tags-apply-not-allowed-one',
 540                                 'tags-apply-not-allowed-multi', $disallowedTags );
 541                 }
 542
 543                 return Status::newGood();
 544         }
 545
 546         /**
 547          * Adds tags to a given change, checking whether it is allowed first, but
 548          * without adding a log entry. Useful for cases where the tag is being added
 549          * along with the action that generated the change (e.g. tagging an edit as
 550          * it is being made).
 551          *
 552          * Extensions should not use this function, unless directly handling a user
 553          * request to add a particular tag. Normally, extensions should call
 554          * ChangeTags::updateTags() instead.
 555          *
 556          * @param array $tags Tags to apply
 557          * @param int|null $rc_id The rc_id of the change to add the tags to
 558          * @param int|null $rev_id The rev_id of the change to add the tags to
 559          * @param int|null $log_id The log_id of the change to add the tags to
 560          * @param string $params Params to put in the ct_params field of table
 561          * 'change_tag' when adding tags
 562          * @param User $user Who to give credit for the action
 563          * @return Status
 564          * @since 1.25
 565          */
 566         public static function addTagsAccompanyingChangeWithChecks(
 567                 array $tags, $rc_id, $rev_id, $log_id, $params, User $user
 568         ) {
 569                 // are we allowed to do this?
 570                 $result = self::canAddTagsAccompanyingChange( $tags, $user );
 571                 if ( !$result->isOK() ) {
 572                         $result->value = null;
 573                         return $result;
 574                 }
 575
 576                 // do it!
 577                 self::addTags( $tags, $rc_id, $rev_id, $log_id, $params );
 578
 579                 return Status::newGood( true );
 580         }
 581
 582         /**
 583          * Is it OK to allow the user to adds and remove the given tags tags to/from a
 584          * change?
 585          *
 586          * Extensions should not use this function, unless directly handling a user
 587          * request to add or remove tags from an existing revision or log entry.
 588          *
 589          * @param array $tagsToAdd Tags that you are interested in adding
 590          * @param array $tagsToRemove Tags that you are interested in removing
 591          * @param User|null $user User whose permission you wish to check, or null to
 592          * check for a generic non-blocked user with the relevant rights
 593          * @return Status
 594          * @since 1.25
 595          */
 596         public static function canUpdateTags( array $tagsToAdd, array $tagsToRemove,
 597                 User $user = null
 598         ) {
 599                 if ( !is_null( $user ) ) {
 600                         if ( !$user->isAllowed( 'changetags' ) ) {
 601                                 return Status::newFatal( 'tags-update-no-permission' );
 602                         } elseif ( $user->isBlocked() ) {
 603                                 return Status::newFatal( 'tags-update-blocked', $user->getName() );
 604                         }
 605                 }
 606
 607                 if ( $tagsToAdd ) {
 608                         // to be added, a tag has to be explicitly defined
 609                         // @todo Allow extensions to define tags that can be applied by users...
 610                         $explicitlyDefinedTags = self::listExplicitlyDefinedTags();
 611                         $diff = array_diff( $tagsToAdd, $explicitlyDefinedTags );
 612                         if ( $diff ) {
 613                                 return self::restrictedTagError( 'tags-update-add-not-allowed-one',
 614                                         'tags-update-add-not-allowed-multi', $diff );
 615                         }
 616                 }
 617
 618                 if ( $tagsToRemove ) {
 619                         // to be removed, a tag must not be defined by an extension, or equivalently it
 620                         // has to be either explicitly defined or not defined at all
 621                         // (assuming no edge case of a tag both explicitly-defined and extension-defined)
 622                         $softwareDefinedTags = self::listSoftwareDefinedTags();
 623                         $intersect = array_intersect( $tagsToRemove, $softwareDefinedTags );
 624                         if ( $intersect ) {
 625                                 return self::restrictedTagError( 'tags-update-remove-not-allowed-one',
 626                                         'tags-update-remove-not-allowed-multi', $intersect );
 627                         }
 628                 }
 629
 630                 return Status::newGood();
 631         }
 632
 633         /**
 634          * Adds and/or removes tags to/from a given change, checking whether it is
 635          * allowed first, and adding a log entry afterwards.
 636          *
 637          * Includes a call to ChangeTags::canUpdateTags(), so your code doesn't need
 638          * to do that. However, it doesn't check whether the *_id parameters are a
 639          * valid combination. That is up to you to enforce. See ApiTag::execute() for
 640          * an example.
 641          *
 642          * Extensions should generally avoid this function. Call
 643          * ChangeTags::updateTags() instead, unless directly handling a user request
 644          * to add or remove tags from an existing revision or log entry.
 645          *
 646          * @param array|null $tagsToAdd If none, pass array() or null
 647          * @param array|null $tagsToRemove If none, pass array() or null
 648          * @param int|null $rc_id The rc_id of the change to add the tags to
 649          * @param int|null $rev_id The rev_id of the change to add the tags to
 650          * @param int|null $log_id The log_id of the change to add the tags to
 651          * @param string $params Params to put in the ct_params field of table
 652          * 'change_tag' when adding tags
 653          * @param string $reason Comment for the log
 654          * @param User $user Who to give credit for the action
 655          * @return Status If successful, the value of this Status object will be an
 656          * object (stdClass) with the following fields:
 657          *  - logId: the ID of the added log entry, or null if no log entry was added
 658          *    (i.e. no operation was performed)
 659          *  - addedTags: an array containing the tags that were actually added
 660          *  - removedTags: an array containing the tags that were actually removed
 661          * @since 1.25
 662          */
 663         public static function updateTagsWithChecks( $tagsToAdd, $tagsToRemove,
 664                 $rc_id, $rev_id, $log_id, $params, $reason, User $user
 665         ) {
 666                 if ( is_null( $tagsToAdd ) ) {
 667                         $tagsToAdd = [];
 668                 }
 669                 if ( is_null( $tagsToRemove ) ) {
 670                         $tagsToRemove = [];
 671                 }
 672                 if ( !$tagsToAdd && !$tagsToRemove ) {
 673                         // no-op, don't bother
 674                         return Status::newGood( (object)[
 675                                 'logId' => null,
 676                                 'addedTags' => [],
 677                                 'removedTags' => [],
 678                         ] );
 679                 }
 680
 681                 // are we allowed to do this?
 682                 $result = self::canUpdateTags( $tagsToAdd, $tagsToRemove, $user );
 683                 if ( !$result->isOK() ) {
 684                         $result->value = null;
 685                         return $result;
 686                 }
 687
 688                 // basic rate limiting
 689                 if ( $user->pingLimiter( 'changetag' ) ) {
 690                         return Status::newFatal( 'actionthrottledtext' );
 691                 }
 692
 693                 // do it!
 694                 list( $tagsAdded, $tagsRemoved, $initialTags ) = self::updateTags( $tagsToAdd,
 695                         $tagsToRemove, $rc_id, $rev_id, $log_id, $params, null, $user );
 696                 if ( !$tagsAdded && !$tagsRemoved ) {
 697                         // no-op, don't log it
 698                         return Status::newGood( (object)[
 699                                 'logId' => null,
 700                                 'addedTags' => [],
 701                                 'removedTags' => [],
 702                         ] );
 703                 }
 704
 705                 // log it
 706                 $logEntry = new ManualLogEntry( 'tag', 'update' );
 707                 $logEntry->setPerformer( $user );
 708                 $logEntry->setComment( $reason );
 709
 710                 // find the appropriate target page
 711                 if ( $rev_id ) {
 712                         $rev = Revision::newFromId( $rev_id );
 713                         if ( $rev ) {
 714                                 $logEntry->setTarget( $rev->getTitle() );
 715                         }
 716                 } elseif ( $log_id ) {
 717                         // This function is from revision deletion logic and has nothing to do with
 718                         // change tags, but it appears to be the only other place in core where we
 719                         // perform logged actions on log items.
 720                         $logEntry->setTarget( RevDelLogList::suggestTarget( null, [ $log_id ] ) );
 721                 }
 722
 723                 if ( !$logEntry->getTarget() ) {
 724                         // target is required, so we have to set something
 725                         $logEntry->setTarget( SpecialPage::getTitleFor( 'Tags' ) );
 726                 }
 727
 728                 $logParams = [
 729                         '4::revid' => $rev_id,
 730                         '5::logid' => $log_id,
 731                         '6:list:tagsAdded' => $tagsAdded,
 732                         '7:number:tagsAddedCount' => count( $tagsAdded ),
 733                         '8:list:tagsRemoved' => $tagsRemoved,
 734                         '9:number:tagsRemovedCount' => count( $tagsRemoved ),
 735                         'initialTags' => $initialTags,
 736                 ];
 737                 $logEntry->setParameters( $logParams );
 738                 $logEntry->setRelations( [ 'Tag' => array_merge( $tagsAdded, $tagsRemoved ) ] );
 739
 740                 $dbw = wfGetDB( DB_MASTER );
 741                 $logId = $logEntry->insert( $dbw );
 742                 // Only send this to UDP, not RC, similar to patrol events
 743                 $logEntry->publish( $logId, 'udp' );
 744
 745                 return Status::newGood( (object)[
 746                         'logId' => $logId,
 747                         'addedTags' => $tagsAdded,
 748                         'removedTags' => $tagsRemoved,
 749                 ] );
 750         }
 751
 752         /**
 753          * Applies all tags-related changes to a query.
 754          * Handles selecting tags, and filtering.
 755          * Needs $tables to be set up properly, so we can figure out which join conditions to use.
 756          *
 757          * WARNING: If $filter_tag contains more than one tag, this function will add DISTINCT,
 758          * which may cause performance problems for your query unless you put the ID field of your
 759          * table at the end of the ORDER BY, and set a GROUP BY equal to the ORDER BY. For example,
 760          * if you had ORDER BY foo_timestamp DESC, you will now need GROUP BY foo_timestamp, foo_id
 761          * ORDER BY foo_timestamp DESC, foo_id DESC.
 762          *
 763          * @param string|array &$tables Table names, see Database::select
 764          * @param string|array &$fields Fields used in query, see Database::select
 765          * @param string|array &$conds Conditions used in query, see Database::select
 766          * @param array &$join_conds Join conditions, see Database::select
 767          * @param string|array &$options Options, see Database::select
 768          * @param string|array $filter_tag Tag(s) to select on
 769          *
 770          * @throws MWException When unable to determine appropriate JOIN condition for tagging
 771          */
 772         public static function modifyDisplayQuery( &$tables, &$fields, &$conds,
 773                 &$join_conds, &$options, $filter_tag = ''
 774         ) {
 775                 global $wgUseTagFilter;
 776
 777                 // Normalize to arrays
 778                 $tables = (array)$tables;
 779                 $fields = (array)$fields;
 780                 $conds = (array)$conds;
 781                 $options = (array)$options;
 782
 783                 $fields['ts_tags'] = self::makeTagSummarySubquery( $tables );
 784
 785                 // Figure out which ID field to use
 786                 if ( in_array( 'recentchanges', $tables ) ) {
 787                         $join_cond = 'ct_rc_id=rc_id';
 788                 } elseif ( in_array( 'logging', $tables ) ) {
 789                         $join_cond = 'ct_log_id=log_id';
 790                 } elseif ( in_array( 'revision', $tables ) ) {
 791                         $join_cond = 'ct_rev_id=rev_id';
 792                 } elseif ( in_array( 'archive', $tables ) ) {
 793                         $join_cond = 'ct_rev_id=ar_rev_id';
 794                 } else {
 795                         throw new MWException( 'Unable to determine appropriate JOIN condition for tagging.' );
 796                 }
 797
 798                 if ( $wgUseTagFilter && $filter_tag ) {
 799                         // Somebody wants to filter on a tag.
 800                         // Add an INNER JOIN on change_tag
 801
 802                         $tables[] = 'change_tag';
 803                         $join_conds['change_tag'] = [ 'INNER JOIN', $join_cond ];
 804                         $filterTagIds = [];
 805                         $changeTagDefStore = MediaWikiServices::getInstance()->getChangeTagDefStore();
 806                         foreach ( (array)$filter_tag as $filterTagName ) {
 807                                 try {
 808                                         $filterTagIds[] = $changeTagDefStore->getId( $filterTagName );
 809                                 } catch ( NameTableAccessException $exception ) {
 810                                         // Return nothing.
 811                                         $conds[] = '0';
 812                                         break;
 813                                 };
 814                         }
 815
 816                         if ( $filterTagIds !== [] ) {
 817                                 $conds['ct_tag_id'] = $filterTagIds;
 818                         }
 819
 820                         if (
 821                                 is_array( $filter_tag ) && count( $filter_tag ) > 1 &&
 822                                 !in_array( 'DISTINCT', $options )
 823                         ) {
 824                                 $options[] = 'DISTINCT';
 825                         }
 826                 }
 827         }
 828
 829         /**
 830          * Make the tag summary subquery based on the given tables and return it.
 831          *
 832          * @param string|array $tables Table names, see Database::select
 833          *
 834          * @return string tag summary subqeury
 835          * @throws MWException When unable to determine appropriate JOIN condition for tagging
 836          */
 837         public static function makeTagSummarySubquery( $tables ) {
 838                 // Normalize to arrays
 839                 $tables = (array)$tables;
 840
 841                 // Figure out which ID field to use
 842                 if ( in_array( 'recentchanges', $tables ) ) {
 843                         $join_cond = 'ct_rc_id=rc_id';
 844                 } elseif ( in_array( 'logging', $tables ) ) {
 845                         $join_cond = 'ct_log_id=log_id';
 846                 } elseif ( in_array( 'revision', $tables ) ) {
 847                         $join_cond = 'ct_rev_id=rev_id';
 848                 } elseif ( in_array( 'archive', $tables ) ) {
 849                         $join_cond = 'ct_rev_id=ar_rev_id';
 850                 } else {
 851                         throw new MWException( 'Unable to determine appropriate JOIN condition for tagging.' );
 852                 }
 853
 854                 $tagTables = [ 'change_tag', 'change_tag_def' ];
 855                 $join_cond_ts_tags = [ 'change_tag_def' => [ 'INNER JOIN', 'ct_tag_id=ctd_id' ] ];
 856                 $field = 'ctd_name';
 857
 858                 return wfGetDB( DB_REPLICA )->buildGroupConcatField(
 859                         ',', $tagTables, $field, $join_cond, $join_cond_ts_tags
 860                 );
 861         }
 862
 863         /**
 864          * Build a text box to select a change tag
 865          *
 866          * @param string $selected Tag to select by default
 867          * @param bool $ooui Use an OOUI TextInputWidget as selector instead of a non-OOUI input field
 868          *        You need to call OutputPage::enableOOUI() yourself.
 869          * @param IContextSource|null $context
 870          * @note Even though it takes null as a valid argument, an IContextSource is preferred
 871          *       in a new code, as the null value can change in the future
 872          * @return array an array of (label, selector)
 873          */
 874         public static function buildTagFilterSelector(
 875                 $selected = '', $ooui = false, IContextSource $context = null
 876         ) {
 877                 if ( !$context ) {
 878                         $context = RequestContext::getMain();
 879                 }
 880
 881                 $config = $context->getConfig();
 882                 if ( !$config->get( 'UseTagFilter' ) || !count( self::listDefinedTags() ) ) {
 883                         return [];
 884                 }
 885
 886                 $data = [
 887                         Html::rawElement(
 888                                 'label',
 889                                 [ 'for' => 'tagfilter' ],
 890                                 $context->msg( 'tag-filter' )->parse()
 891                         )
 892                 ];
 893
 894                 if ( $ooui ) {
 895                         $data[] = new OOUI\TextInputWidget( [
 896                                 'id' => 'tagfilter',
 897                                 'name' => 'tagfilter',
 898                                 'value' => $selected,
 899                                 'classes' => 'mw-tagfilter-input',
 900                         ] );
 901                 } else {
 902                         $data[] = Xml::input(
 903                                 'tagfilter',
 904                                 20,
 905                                 $selected,
 906                                 [ 'class' => 'mw-tagfilter-input mw-ui-input mw-ui-input-inline', 'id' => 'tagfilter' ]
 907                         );
 908                 }
 909
 910                 return $data;
 911         }
 912
 913         /**
 914          * Defines a tag in the valid_tag table and/or update ctd_user_defined field in change_tag_def,
 915          * without checking that the tag name is valid.
 916          * Extensions should NOT use this function; they can use the ListDefinedTags
 917          * hook instead.
 918          *
 919          * @param string $tag Tag to create
 920          * @since 1.25
 921          */
 922         public static function defineTag( $tag ) {
 923                 $dbw = wfGetDB( DB_MASTER );
 924                 $tagDef = [
 925                         'ctd_name' => $tag,
 926                         'ctd_user_defined' => 1,
 927                         'ctd_count' => 0
 928                 ];
 929                 $dbw->upsert(
 930                         'change_tag_def',
 931                         $tagDef,
 932                         [ 'ctd_name' ],
 933                         [ 'ctd_user_defined' => 1 ],
 934                         __METHOD__
 935                 );
 936
 937                 // clear the memcache of defined tags
 938                 self::purgeTagCacheAll();
 939         }
 940
 941         /**
 942          * Removes a tag from the valid_tag table and/or update ctd_user_defined field in change_tag_def.
 943          * The tag may remain in use by extensions, and may still show up as 'defined'
 944          * if an extension is setting it from the ListDefinedTags hook.
 945          *
 946          * @param string $tag Tag to remove
 947          * @since 1.25
 948          */
 949         public static function undefineTag( $tag ) {
 950                 $dbw = wfGetDB( DB_MASTER );
 951
 952                 $dbw->update(
 953                         'change_tag_def',
 954                         [ 'ctd_user_defined' => 0 ],
 955                         [ 'ctd_name' => $tag ],
 956                         __METHOD__
 957                 );
 958
 959                 $dbw->delete(
 960                         'change_tag_def',
 961                         [ 'ctd_name' => $tag, 'ctd_count' => 0 ],
 962                         __METHOD__
 963                 );
 964
 965                 // clear the memcache of defined tags
 966                 self::purgeTagCacheAll();
 967         }
 968
 969         /**
 970          * Writes a tag action into the tag management log.
 971          *
 972          * @param string $action
 973          * @param string $tag
 974          * @param string $reason
 975          * @param User $user Who to attribute the action to
 976          * @param int|null $tagCount For deletion only, how many usages the tag had before
 977          * it was deleted.
 978          * @param array $logEntryTags Change tags to apply to the entry
 979          * that will be created in the tag management log
 980          * @return int ID of the inserted log entry
 981          * @since 1.25
 982          */
 983         protected static function logTagManagementAction( $action, $tag, $reason,
 984                 User $user, $tagCount = null, array $logEntryTags = []
 985         ) {
 986                 $dbw = wfGetDB( DB_MASTER );
 987
 988                 $logEntry = new ManualLogEntry( 'managetags', $action );
 989                 $logEntry->setPerformer( $user );
 990                 // target page is not relevant, but it has to be set, so we just put in
 991                 // the title of Special:Tags
 992                 $logEntry->setTarget( Title::newFromText( 'Special:Tags' ) );
 993                 $logEntry->setComment( $reason );
 994
 995                 $params = [ '4::tag' => $tag ];
 996                 if ( !is_null( $tagCount ) ) {
 997                         $params['5:number:count'] = $tagCount;
 998                 }
 999                 $logEntry->setParameters( $params );
1000                 $logEntry->setRelations( [ 'Tag' => $tag ] );
1001                 $logEntry->setTags( $logEntryTags );
1002
1003                 $logId = $logEntry->insert( $dbw );
1004                 $logEntry->publish( $logId );
1005                 return $logId;
1006         }
1007
1008         /**
1009          * Is it OK to allow the user to activate this tag?
1010          *
1011          * @param string $tag Tag that you are interested in activating
1012          * @param User|null $user User whose permission you wish to check, or null if
1013          * you don't care (e.g. maintenance scripts)
1014          * @return Status
1015          * @since 1.25
1016          */
1017         public static function canActivateTag( $tag, User $user = null ) {
1018                 if ( !is_null( $user ) ) {
1019                         if ( !$user->isAllowed( 'managechangetags' ) ) {
1020                                 return Status::newFatal( 'tags-manage-no-permission' );
1021                         } elseif ( $user->isBlocked() ) {
1022                                 return Status::newFatal( 'tags-manage-blocked', $user->getName() );
1023                         }
1024                 }
1025
1026                 // defined tags cannot be activated (a defined tag is either extension-
1027                 // defined, in which case the extension chooses whether or not to active it;
1028                 // or user-defined, in which case it is considered active)
1029                 $definedTags = self::listDefinedTags();
1030                 if ( in_array( $tag, $definedTags ) ) {
1031                         return Status::newFatal( 'tags-activate-not-allowed', $tag );
1032                 }
1033
1034                 // non-existing tags cannot be activated
1035                 $tagUsage = self::tagUsageStatistics();
1036                 if ( !isset( $tagUsage[$tag] ) ) { // we already know the tag is undefined
1037                         return Status::newFatal( 'tags-activate-not-found', $tag );
1038                 }
1039
1040                 return Status::newGood();
1041         }
1042
1043         /**
1044          * Activates a tag, checking whether it is allowed first, and adding a log
1045          * entry afterwards.
1046          *
1047          * Includes a call to ChangeTag::canActivateTag(), so your code doesn't need
1048          * to do that.
1049          *
1050          * @param string $tag
1051          * @param string $reason
1052          * @param User $user Who to give credit for the action
1053          * @param bool $ignoreWarnings Can be used for API interaction, default false
1054          * @param array $logEntryTags Change tags to apply to the entry
1055          * that will be created in the tag management log
1056          * @return Status If successful, the Status contains the ID of the added log
1057          * entry as its value
1058          * @since 1.25
1059          */
1060         public static function activateTagWithChecks( $tag, $reason, User $user,
1061                 $ignoreWarnings = false, array $logEntryTags = []
1062         ) {
1063                 // are we allowed to do this?
1064                 $result = self::canActivateTag( $tag, $user );
1065                 if ( $ignoreWarnings ? !$result->isOK() : !$result->isGood() ) {
1066                         $result->value = null;
1067                         return $result;
1068                 }
1069
1070                 // do it!
1071                 self::defineTag( $tag );
1072
1073                 // log it
1074                 $logId = self::logTagManagementAction( 'activate', $tag, $reason, $user,
1075                         null, $logEntryTags );
1076
1077                 return Status::newGood( $logId );
1078         }
1079
1080         /**
1081          * Is it OK to allow the user to deactivate this tag?
1082          *
1083          * @param string $tag Tag that you are interested in deactivating
1084          * @param User|null $user User whose permission you wish to check, or null if
1085          * you don't care (e.g. maintenance scripts)
1086          * @return Status
1087          * @since 1.25
1088          */
1089         public static function canDeactivateTag( $tag, User $user = null ) {
1090                 if ( !is_null( $user ) ) {
1091                         if ( !$user->isAllowed( 'managechangetags' ) ) {
1092                                 return Status::newFatal( 'tags-manage-no-permission' );
1093                         } elseif ( $user->isBlocked() ) {
1094                                 return Status::newFatal( 'tags-manage-blocked', $user->getName() );
1095                         }
1096                 }
1097
1098                 // only explicitly-defined tags can be deactivated
1099                 $explicitlyDefinedTags = self::listExplicitlyDefinedTags();
1100                 if ( !in_array( $tag, $explicitlyDefinedTags ) ) {
1101                         return Status::newFatal( 'tags-deactivate-not-allowed', $tag );
1102                 }
1103                 return Status::newGood();
1104         }
1105
1106         /**
1107          * Deactivates a tag, checking whether it is allowed first, and adding a log
1108          * entry afterwards.
1109          *
1110          * Includes a call to ChangeTag::canDeactivateTag(), so your code doesn't need
1111          * to do that.
1112          *
1113          * @param string $tag
1114          * @param string $reason
1115          * @param User $user Who to give credit for the action
1116          * @param bool $ignoreWarnings Can be used for API interaction, default false
1117          * @param array $logEntryTags Change tags to apply to the entry
1118          * that will be created in the tag management log
1119          * @return Status If successful, the Status contains the ID of the added log
1120          * entry as its value
1121          * @since 1.25
1122          */
1123         public static function deactivateTagWithChecks( $tag, $reason, User $user,
1124                 $ignoreWarnings = false, array $logEntryTags = []
1125         ) {
1126                 // are we allowed to do this?
1127                 $result = self::canDeactivateTag( $tag, $user );
1128                 if ( $ignoreWarnings ? !$result->isOK() : !$result->isGood() ) {
1129                         $result->value = null;
1130                         return $result;
1131                 }
1132
1133                 // do it!
1134                 self::undefineTag( $tag );
1135
1136                 // log it
1137                 $logId = self::logTagManagementAction( 'deactivate', $tag, $reason, $user,
1138                         null, $logEntryTags );
1139
1140                 return Status::newGood( $logId );
1141         }
1142
1143         /**
1144          * Is the tag name valid?
1145          *
1146          * @param string $tag Tag that you are interested in creating
1147          * @return Status
1148          * @since 1.30
1149          */
1150         public static function isTagNameValid( $tag ) {
1151                 // no empty tags
1152                 if ( $tag === '' ) {
1153                         return Status::newFatal( 'tags-create-no-name' );
1154                 }
1155
1156                 // tags cannot contain commas (used as a delimiter in tag_summary table),
1157                 // pipe (used as a delimiter between multiple tags in
1158                 // SpecialRecentchanges and friends), or slashes (would break tag description messages in
1159                 // MediaWiki namespace)
1160                 if ( strpos( $tag, ',' ) !== false || strpos( $tag, '|' ) !== false
1161                         || strpos( $tag, '/' ) !== false ) {
1162                         return Status::newFatal( 'tags-create-invalid-chars' );
1163                 }
1164
1165                 // could the MediaWiki namespace description messages be created?
1166                 $title = Title::makeTitleSafe( NS_MEDIAWIKI, "Tag-$tag-description" );
1167                 if ( is_null( $title ) ) {
1168                         return Status::newFatal( 'tags-create-invalid-title-chars' );
1169                 }
1170
1171                 return Status::newGood();
1172         }
1173
1174         /**
1175          * Is it OK to allow the user to create this tag?
1176          *
1177          * Extensions should NOT use this function. In most cases, a tag can be
1178          * defined using the ListDefinedTags hook without any checking.
1179          *
1180          * @param string $tag Tag that you are interested in creating
1181          * @param User|null $user User whose permission you wish to check, or null if
1182          * you don't care (e.g. maintenance scripts)
1183          * @return Status
1184          * @since 1.25
1185          */
1186         public static function canCreateTag( $tag, User $user = null ) {
1187                 if ( !is_null( $user ) ) {
1188                         if ( !$user->isAllowed( 'managechangetags' ) ) {
1189                                 return Status::newFatal( 'tags-manage-no-permission' );
1190                         } elseif ( $user->isBlocked() ) {
1191                                 return Status::newFatal( 'tags-manage-blocked', $user->getName() );
1192                         }
1193                 }
1194
1195                 $status = self::isTagNameValid( $tag );
1196                 if ( !$status->isGood() ) {
1197                         return $status;
1198                 }
1199
1200                 // does the tag already exist?
1201                 $tagUsage = self::tagUsageStatistics();
1202                 if ( isset( $tagUsage[$tag] ) || in_array( $tag, self::listDefinedTags() ) ) {
1203                         return Status::newFatal( 'tags-create-already-exists', $tag );
1204                 }
1205
1206                 // check with hooks
1207                 $canCreateResult = Status::newGood();
1208                 Hooks::run( 'ChangeTagCanCreate', [ $tag, $user, &$canCreateResult ] );
1209                 return $canCreateResult;
1210         }
1211
1212         /**
1213          * Creates a tag by adding a row to the `valid_tag` table.
1214          * and/or add it to `change_tag_def` table.
1215          *
1216          * Extensions should NOT use this function; they can use the ListDefinedTags
1217          * hook instead.
1218          *
1219          * Includes a call to ChangeTag::canCreateTag(), so your code doesn't need to
1220          * do that.
1221          *
1222          * @param string $tag
1223          * @param string $reason
1224          * @param User $user Who to give credit for the action
1225          * @param bool $ignoreWarnings Can be used for API interaction, default false
1226          * @param array $logEntryTags Change tags to apply to the entry
1227          * that will be created in the tag management log
1228          * @return Status If successful, the Status contains the ID of the added log
1229          * entry as its value
1230          * @since 1.25
1231          */
1232         public static function createTagWithChecks( $tag, $reason, User $user,
1233                 $ignoreWarnings = false, array $logEntryTags = []
1234         ) {
1235                 // are we allowed to do this?
1236                 $result = self::canCreateTag( $tag, $user );
1237                 if ( $ignoreWarnings ? !$result->isOK() : !$result->isGood() ) {
1238                         $result->value = null;
1239                         return $result;
1240                 }
1241
1242                 // do it!
1243                 self::defineTag( $tag );
1244
1245                 // log it
1246                 $logId = self::logTagManagementAction( 'create', $tag, $reason, $user,
1247                         null, $logEntryTags );
1248
1249                 return Status::newGood( $logId );
1250         }
1251
1252         /**
1253          * Permanently removes all traces of a tag from the DB. Good for removing
1254          * misspelt or temporary tags.
1255          *
1256          * This function should be directly called by maintenance scripts only, never
1257          * by user-facing code. See deleteTagWithChecks() for functionality that can
1258          * safely be exposed to users.
1259          *
1260          * @param string $tag Tag to remove
1261          * @return Status The returned status will be good unless a hook changed it
1262          * @since 1.25
1263          */
1264         public static function deleteTagEverywhere( $tag ) {
1265                 $dbw = wfGetDB( DB_MASTER );
1266                 $dbw->startAtomic( __METHOD__ );
1267
1268                 // delete from valid_tag and/or set ctd_user_defined = 0
1269                 self::undefineTag( $tag );
1270
1271                 $tagId = MediaWikiServices::getInstance()->getChangeTagDefStore()->getId( $tag );
1272                 $conditions = [ 'ct_tag_id' => $tagId ];
1273
1274                 // find out which revisions use this tag, so we can delete from tag_summary
1275                 $result = $dbw->select( 'change_tag',
1276                         [ 'ct_rc_id', 'ct_log_id', 'ct_rev_id' ],
1277                         $conditions,
1278                         __METHOD__ );
1279                 foreach ( $result as $row ) {
1280                         // remove the tag from the relevant row of tag_summary
1281                         $tagsToAdd = [];
1282                         $tagsToRemove = [ $tag ];
1283                         self::updateTagSummaryRow( $tagsToAdd, $tagsToRemove, $row->ct_rc_id,
1284                                 $row->ct_rev_id, $row->ct_log_id );
1285                 }
1286
1287                 // delete from change_tag
1288                 $tagId = MediaWikiServices::getInstance()->getChangeTagDefStore()->getId( $tag );
1289                 $dbw->delete( 'change_tag', [ 'ct_tag_id' => $tagId ], __METHOD__ );
1290                 $dbw->delete( 'change_tag_def', [ 'ctd_name' => $tag ], __METHOD__ );
1291                 $dbw->endAtomic( __METHOD__ );
1292
1293                 // give extensions a chance
1294                 $status = Status::newGood();
1295                 Hooks::run( 'ChangeTagAfterDelete', [ $tag, &$status ] );
1296                 // let's not allow error results, as the actual tag deletion succeeded
1297                 if ( !$status->isOK() ) {
1298                         wfDebug( 'ChangeTagAfterDelete error condition downgraded to warning' );
1299                         $status->setOK( true );
1300                 }
1301
1302                 // clear the memcache of defined tags
1303                 self::purgeTagCacheAll();
1304
1305                 return $status;
1306         }
1307
1308         /**
1309          * Is it OK to allow the user to delete this tag?
1310          *
1311          * @param string $tag Tag that you are interested in deleting
1312          * @param User|null $user User whose permission you wish to check, or null if
1313          * you don't care (e.g. maintenance scripts)
1314          * @return Status
1315          * @since 1.25
1316          */
1317         public static function canDeleteTag( $tag, User $user = null ) {
1318                 $tagUsage = self::tagUsageStatistics();
1319
1320                 if ( !is_null( $user ) ) {
1321                         if ( !$user->isAllowed( 'deletechangetags' ) ) {
1322                                 return Status::newFatal( 'tags-delete-no-permission' );
1323                         } elseif ( $user->isBlocked() ) {
1324                                 return Status::newFatal( 'tags-manage-blocked', $user->getName() );
1325                         }
1326                 }
1327
1328                 if ( !isset( $tagUsage[$tag] ) && !in_array( $tag, self::listDefinedTags() ) ) {
1329                         return Status::newFatal( 'tags-delete-not-found', $tag );
1330                 }
1331
1332                 if ( isset( $tagUsage[$tag] ) && $tagUsage[$tag] > self::MAX_DELETE_USES ) {
1333                         return Status::newFatal( 'tags-delete-too-many-uses', $tag, self::MAX_DELETE_USES );
1334                 }
1335
1336                 $softwareDefined = self::listSoftwareDefinedTags();
1337                 if ( in_array( $tag, $softwareDefined ) ) {
1338                         // extension-defined tags can't be deleted unless the extension
1339                         // specifically allows it
1340                         $status = Status::newFatal( 'tags-delete-not-allowed' );
1341                 } else {
1342                         // user-defined tags are deletable unless otherwise specified
1343                         $status = Status::newGood();
1344                 }
1345
1346                 Hooks::run( 'ChangeTagCanDelete', [ $tag, $user, &$status ] );
1347                 return $status;
1348         }
1349
1350         /**
1351          * Deletes a tag, checking whether it is allowed first, and adding a log entry
1352          * afterwards.
1353          *
1354          * Includes a call to ChangeTag::canDeleteTag(), so your code doesn't need to
1355          * do that.
1356          *
1357          * @param string $tag
1358          * @param string $reason
1359          * @param User $user Who to give credit for the action
1360          * @param bool $ignoreWarnings Can be used for API interaction, default false
1361          * @param array $logEntryTags Change tags to apply to the entry
1362          * that will be created in the tag management log
1363          * @return Status If successful, the Status contains the ID of the added log
1364          * entry as its value
1365          * @since 1.25
1366          */
1367         public static function deleteTagWithChecks( $tag, $reason, User $user,
1368                 $ignoreWarnings = false, array $logEntryTags = []
1369         ) {
1370                 // are we allowed to do this?
1371                 $result = self::canDeleteTag( $tag, $user );
1372                 if ( $ignoreWarnings ? !$result->isOK() : !$result->isGood() ) {
1373                         $result->value = null;
1374                         return $result;
1375                 }
1376
1377                 // store the tag usage statistics
1378                 $tagUsage = self::tagUsageStatistics();
1379                 $hitcount = $tagUsage[$tag] ?? 0;
1380
1381                 // do it!
1382                 $deleteResult = self::deleteTagEverywhere( $tag );
1383                 if ( !$deleteResult->isOK() ) {
1384                         return $deleteResult;
1385                 }
1386
1387                 // log it
1388                 $logId = self::logTagManagementAction( 'delete', $tag, $reason, $user,
1389                         $hitcount, $logEntryTags );
1390
1391                 $deleteResult->value = $logId;
1392                 return $deleteResult;
1393         }
1394
1395         /**
1396          * Lists those tags which core or extensions report as being "active".
1397          *
1398          * @return array
1399          * @since 1.25
1400          */
1401         public static function listSoftwareActivatedTags() {
1402                 // core active tags
1403                 $tags = self::getSoftwareTags();
1404                 if ( !Hooks::isRegistered( 'ChangeTagsListActive' ) ) {
1405                         return $tags;
1406                 }
1407                 $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
1408                 return $cache->getWithSetCallback(
1409                         $cache->makeKey( 'active-tags' ),
1410                         WANObjectCache::TTL_MINUTE * 5,
1411                         function ( $oldValue, &$ttl, array &$setOpts ) use ( $tags ) {
1412                                 $setOpts += Database::getCacheSetOptions( wfGetDB( DB_REPLICA ) );
1413
1414                                 // Ask extensions which tags they consider active
1415                                 Hooks::run( 'ChangeTagsListActive', [ &$tags ] );
1416                                 return $tags;
1417                         },
1418                         [
1419                                 'checkKeys' => [ $cache->makeKey( 'active-tags' ) ],
1420                                 'lockTSE' => WANObjectCache::TTL_MINUTE * 5,
1421                                 'pcTTL' => WANObjectCache::TTL_PROC_LONG
1422                         ]
1423                 );
1424         }
1425
1426         /**
1427          * Basically lists defined tags which count even if they aren't applied to anything.
1428          * It returns a union of the results of listExplicitlyDefinedTags()
1429          *
1430          * @return string[] Array of strings: tags
1431          */
1432         public static function listDefinedTags() {
1433                 $tags1 = self::listExplicitlyDefinedTags();
1434                 $tags2 = self::listSoftwareDefinedTags();
1435                 return array_values( array_unique( array_merge( $tags1, $tags2 ) ) );
1436         }
1437
1438         /**
1439          * Lists tags explicitly defined in the `valid_tag` table of the database.
1440          * Tags in table 'change_tag' which are not in table 'valid_tag' are not
1441          * included. In case of new backend loads the data from `change_tag_def` table.
1442          *
1443          * Tries memcached first.
1444          *
1445          * @return string[] Array of strings: tags
1446          * @since 1.25
1447          */
1448         public static function listExplicitlyDefinedTags() {
1449                 $fname = __METHOD__;
1450
1451                 $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
1452                 return $cache->getWithSetCallback(
1453                         $cache->makeKey( 'valid-tags-db' ),
1454                         WANObjectCache::TTL_MINUTE * 5,
1455                         function ( $oldValue, &$ttl, array &$setOpts ) use ( $fname ) {
1456                                 $dbr = wfGetDB( DB_REPLICA );
1457
1458                                 $setOpts += Database::getCacheSetOptions( $dbr );
1459
1460                                 $tags = $dbr->selectFieldValues(
1461                                         'change_tag_def',
1462                                         'ctd_name',
1463                                         [ 'ctd_user_defined' => 1 ],
1464                                         $fname
1465                                 );
1466
1467                                 return array_filter( array_unique( $tags ) );
1468                         },
1469                         [
1470                                 'checkKeys' => [ $cache->makeKey( 'valid-tags-db' ) ],
1471                                 'lockTSE' => WANObjectCache::TTL_MINUTE * 5,
1472                                 'pcTTL' => WANObjectCache::TTL_PROC_LONG
1473                         ]
1474                 );
1475         }
1476
1477         /**
1478          * Lists tags defined by core or extensions using the ListDefinedTags hook.
1479          * Extensions need only define those tags they deem to be in active use.
1480          *
1481          * Tries memcached first.
1482          *
1483          * @return string[] Array of strings: tags
1484          * @since 1.25
1485          */
1486         public static function listSoftwareDefinedTags() {
1487                 // core defined tags
1488                 $tags = self::getSoftwareTags( true );
1489                 if ( !Hooks::isRegistered( 'ListDefinedTags' ) ) {
1490                         return $tags;
1491                 }
1492                 $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
1493                 return $cache->getWithSetCallback(
1494                         $cache->makeKey( 'valid-tags-hook' ),
1495                         WANObjectCache::TTL_MINUTE * 5,
1496                         function ( $oldValue, &$ttl, array &$setOpts ) use ( $tags ) {
1497                                 $setOpts += Database::getCacheSetOptions( wfGetDB( DB_REPLICA ) );
1498
1499                                 Hooks::run( 'ListDefinedTags', [ &$tags ] );
1500                                 return array_filter( array_unique( $tags ) );
1501                         },
1502                         [
1503                                 'checkKeys' => [ $cache->makeKey( 'valid-tags-hook' ) ],
1504                                 'lockTSE' => WANObjectCache::TTL_MINUTE * 5,
1505                                 'pcTTL' => WANObjectCache::TTL_PROC_LONG
1506                         ]
1507                 );
1508         }
1509
1510         /**
1511          * Invalidates the short-term cache of defined tags used by the
1512          * list*DefinedTags functions, as well as the tag statistics cache.
1513          * @since 1.25
1514          */
1515         public static function purgeTagCacheAll() {
1516                 $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
1517
1518                 $cache->touchCheckKey( $cache->makeKey( 'active-tags' ) );
1519                 $cache->touchCheckKey( $cache->makeKey( 'valid-tags-db' ) );
1520                 $cache->touchCheckKey( $cache->makeKey( 'valid-tags-hook' ) );
1521
1522                 self::purgeTagUsageCache();
1523         }
1524
1525         /**
1526          * Invalidates the tag statistics cache only.
1527          * @since 1.25
1528          */
1529         public static function purgeTagUsageCache() {
1530                 $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
1531
1532                 $cache->touchCheckKey( $cache->makeKey( 'change-tag-statistics' ) );
1533         }
1534
1535         /**
1536          * Returns a map of any tags used on the wiki to number of edits
1537          * tagged with them, ordered descending by the hitcount.
1538          * This does not include tags defined somewhere that have never been applied.
1539          * @return array Array of string => int
1540          */
1541         public static function tagUsageStatistics() {
1542                 $dbr = wfGetDB( DB_REPLICA );
1543                 $res = $dbr->select(
1544                         'change_tag_def',
1545                         [ 'ctd_name', 'ctd_count' ],
1546                         [],
1547                         __METHOD__,
1548                         [ 'ORDER BY' => 'ctd_count DESC' ]
1549                 );
1550
1551                 $out = [];
1552                 foreach ( $res as $row ) {
1553                         $out[$row->ctd_name] = $row->ctd_count;
1554                 }
1555
1556                 return $out;
1557         }
1558
1559         /**
1560          * Indicate whether change tag editing UI is relevant
1561          *
1562          * Returns true if the user has the necessary right and there are any
1563          * editable tags defined.
1564          *
1565          * This intentionally doesn't check "any addable || any deletable", because
1566          * it seems like it would be more confusing than useful if the checkboxes
1567          * suddenly showed up because some abuse filter stopped defining a tag and
1568          * then suddenly disappeared when someone deleted all uses of that tag.
1569          *
1570          * @param User $user
1571          * @return bool
1572          */
1573         public static function showTagEditingUI( User $user ) {
1574                 return $user->isAllowed( 'changetags' ) && (bool)self::listExplicitlyDefinedTags();
1575         }
1576 }