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          */
  92         public static function formatSummaryRow( $tags, $page, IContextSource $context = null ) {
  93                 if ( !$tags ) {
  94                         return [ '', [] ];
  95                 }
  96                 if ( !$context ) {
  97                         $context = RequestContext::getMain();
  98                 }
  99
 100                 $classes = [];
 101
 102                 $tags = explode( ',', $tags );
 103                 $displayTags = [];
 104                 foreach ( $tags as $tag ) {
 105                         if ( !$tag ) {
 106                                 continue;
 107                         }
 108                         $description = self::tagDescription( $tag, $context );
 109                         if ( $description === false ) {
 110                                 continue;
 111                         }
 112                         $displayTags[] = Xml::tags(
 113                                 'span',
 114                                 [ 'class' => 'mw-tag-marker ' .
 115                                                                 Sanitizer::escapeClass( "mw-tag-marker-$tag" ) ],
 116                                 $description
 117                         );
 118                         $classes[] = Sanitizer::escapeClass( "mw-tag-$tag" );
 119                 }
 120
 121                 if ( !$displayTags ) {
 122                         return [ '', [] ];
 123                 }
 124
 125                 $markers = $context->msg( 'tag-list-wrapper' )
 126                         ->numParams( count( $displayTags ) )
 127                         ->rawParams( $context->getLanguage()->commaList( $displayTags ) )
 128                         ->parse();
 129                 $markers = Xml::tags( 'span', [ 'class' => 'mw-tag-markers' ], $markers );
 130
 131                 return [ $markers, $classes ];
 132         }
 133
 134         /**
 135          * Get a short description for a tag.
 136          *
 137          * Checks if message key "mediawiki:tag-$tag" exists. If it does not,
 138          * returns the HTML-escaped tag name. Uses the message if the message
 139          * exists, provided it is not disabled. If the message is disabled,
 140          * we consider the tag hidden, and return false.
 141          *
 142          * @param string $tag
 143          * @param IContextSource $context
 144          * @return string|bool Tag description or false if tag is to be hidden.
 145          * @since 1.25 Returns false if tag is to be hidden.
 146          */
 147         public static function tagDescription( $tag, IContextSource $context ) {
 148                 $msg = $context->msg( "tag-$tag" );
 149                 if ( !$msg->exists() ) {
 150                         // No such message, so return the HTML-escaped tag name.
 151                         return htmlspecialchars( $tag );
 152                 }
 153                 if ( $msg->isDisabled() ) {
 154                         // The message exists but is disabled, hide the tag.
 155                         return false;
 156                 }
 157
 158                 // Message exists and isn't disabled, use it.
 159                 return $msg->parse();
 160         }
 161
 162         /**
 163          * Get the message object for the tag's long description.
 164          *
 165          * Checks if message key "mediawiki:tag-$tag-description" exists. If it does not,
 166          * or if message is disabled, returns false. Otherwise, returns the message object
 167          * for the long description.
 168          *
 169          * @param string $tag
 170          * @param IContextSource $context
 171          * @return Message|bool Message object of the tag long description or false if
 172          *  there is no description.
 173          */
 174         public static function tagLongDescriptionMessage( $tag, IContextSource $context ) {
 175                 $msg = $context->msg( "tag-$tag-description" );
 176                 if ( !$msg->exists() ) {
 177                         return false;
 178                 }
 179                 if ( $msg->isDisabled() ) {
 180                         // The message exists but is disabled, hide the description.
 181                         return false;
 182                 }
 183
 184                 // Message exists and isn't disabled, use it.
 185                 return $msg;
 186         }
 187
 188         /**
 189          * Get truncated message for the tag's long description.
 190          *
 191          * @param string $tag Tag name.
 192          * @param int $length Maximum length of truncated message, including ellipsis.
 193          * @param IContextSource $context
 194          *
 195          * @return string Truncated long tag description.
 196          */
 197         public static function truncateTagDescription( $tag, $length, IContextSource $context ) {
 198                 $originalDesc = self::tagLongDescriptionMessage( $tag, $context );
 199                 // If there is no tag description, return empty string
 200                 if ( !$originalDesc ) {
 201                         return '';
 202                 }
 203
 204                 $taglessDesc = Sanitizer::stripAllTags( $originalDesc->parse() );
 205
 206                 return $context->getLanguage()->truncateForVisual( $taglessDesc, $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|null $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|null $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                 global $wgChangeTagsSchemaMigrationStage;
 265
 266                 $tagsToAdd = array_filter( (array)$tagsToAdd ); // Make sure we're submitting all tags...
 267                 $tagsToRemove = array_filter( (array)$tagsToRemove );
 268
 269                 if ( !$rc_id && !$rev_id && !$log_id ) {
 270                         throw new MWException( 'At least one of: RCID, revision ID, and log ID MUST be ' .
 271                                 'specified when adding or removing a tag from a change!' );
 272                 }
 273
 274                 $dbw = wfGetDB( DB_MASTER );
 275
 276                 // Might as well look for rcids and so on.
 277                 if ( !$rc_id ) {
 278                         // Info might be out of date, somewhat fractionally, on replica DB.
 279                         // LogEntry/LogPage and WikiPage match rev/log/rc timestamps,
 280                         // so use that relation to avoid full table scans.
 281                         if ( $log_id ) {
 282                                 $rc_id = $dbw->selectField(
 283                                         [ 'logging', 'recentchanges' ],
 284                                         'rc_id',
 285                                         [
 286                                                 'log_id' => $log_id,
 287                                                 'rc_timestamp = log_timestamp',
 288                                                 'rc_logid = log_id'
 289                                         ],
 290                                         __METHOD__
 291                                 );
 292                         } elseif ( $rev_id ) {
 293                                 $rc_id = $dbw->selectField(
 294                                         [ 'revision', 'recentchanges' ],
 295                                         'rc_id',
 296                                         [
 297                                                 'rev_id' => $rev_id,
 298                                                 'rc_timestamp = rev_timestamp',
 299                                                 'rc_this_oldid = rev_id'
 300                                         ],
 301                                         __METHOD__
 302                                 );
 303                         }
 304                 } elseif ( !$log_id && !$rev_id ) {
 305                         // Info might be out of date, somewhat fractionally, on replica DB.
 306                         $log_id = $dbw->selectField(
 307                                 'recentchanges',
 308                                 'rc_logid',
 309                                 [ 'rc_id' => $rc_id ],
 310                                 __METHOD__
 311                         );
 312                         $rev_id = $dbw->selectField(
 313                                 'recentchanges',
 314                                 'rc_this_oldid',
 315                                 [ 'rc_id' => $rc_id ],
 316                                 __METHOD__
 317                         );
 318                 }
 319
 320                 if ( $log_id && !$rev_id ) {
 321                         $rev_id = $dbw->selectField(
 322                                 'log_search',
 323                                 'ls_value',
 324                                 [ 'ls_field' => 'associated_rev_id', 'ls_log_id' => $log_id ],
 325                                 __METHOD__
 326                         );
 327                 } elseif ( !$log_id && $rev_id ) {
 328                         $log_id = $dbw->selectField(
 329                                 'log_search',
 330                                 'ls_log_id',
 331                                 [ 'ls_field' => 'associated_rev_id', 'ls_value' => $rev_id ],
 332                                 __METHOD__
 333                         );
 334                 }
 335
 336                 // update the tag_summary row
 337                 $prevTags = [];
 338                 if ( !self::updateTagSummaryRow( $tagsToAdd, $tagsToRemove, $rc_id, $rev_id,
 339                         $log_id, $prevTags )
 340                 ) {
 341                         // nothing to do
 342                         return [ [], [], $prevTags ];
 343                 }
 344
 345                 // insert a row into change_tag for each new tag
 346                 $changeTagDefStore = MediaWikiServices::getInstance()->getChangeTagDefStore();
 347                 if ( count( $tagsToAdd ) ) {
 348                         $changeTagMapping = [];
 349                         if ( $wgChangeTagsSchemaMigrationStage > MIGRATION_OLD ) {
 350                                 foreach ( $tagsToAdd as $tag ) {
 351                                         $changeTagMapping[$tag] = $changeTagDefStore->acquireId( $tag );
 352                                 }
 353
 354                                 $dbw->update(
 355                                         'change_tag_def',
 356                                         [ 'ctd_count = ctd_count + 1' ],
 357                                         [ 'ctd_name' => $tagsToAdd ],
 358                                         __METHOD__
 359                                 );
 360                         }
 361
 362                         $tagsRows = [];
 363                         foreach ( $tagsToAdd as $tag ) {
 364                                 if ( $wgChangeTagsSchemaMigrationStage > MIGRATION_WRITE_BOTH ) {
 365                                         $tagName = null;
 366                                 } else {
 367                                         $tagName = $tag;
 368                                 }
 369                                 // Filter so we don't insert NULLs as zero accidentally.
 370                                 // Keep in mind that $rc_id === null means "I don't care/know about the
 371                                 // rc_id, just delete $tag on this revision/log entry". It doesn't
 372                                 // mean "only delete tags on this revision/log WHERE rc_id IS NULL".
 373                                 $tagsRows[] = array_filter(
 374                                         [
 375                                                 'ct_tag' => $tagName,
 376                                                 'ct_rc_id' => $rc_id,
 377                                                 'ct_log_id' => $log_id,
 378                                                 'ct_rev_id' => $rev_id,
 379                                                 'ct_params' => $params,
 380                                                 'ct_tag_id' => $changeTagMapping[$tag] ?? null,
 381                                         ]
 382                                 );
 383
 384                         }
 385
 386                         $dbw->insert( 'change_tag', $tagsRows, __METHOD__, [ 'IGNORE' ] );
 387                 }
 388
 389                 // delete from change_tag
 390                 if ( count( $tagsToRemove ) ) {
 391                         foreach ( $tagsToRemove as $tag ) {
 392                                 if ( $wgChangeTagsSchemaMigrationStage > MIGRATION_WRITE_BOTH ) {
 393                                         $tagName = null;
 394                                         $tagId = $changeTagDefStore->getId( $tag );
 395                                 } else {
 396                                         $tagName = $tag;
 397                                         $tagId = null;
 398                                 }
 399                                 $conds = array_filter(
 400                                         [
 401                                                 'ct_tag' => $tagName,
 402                                                 'ct_rc_id' => $rc_id,
 403                                                 'ct_log_id' => $log_id,
 404                                                 'ct_rev_id' => $rev_id,
 405                                                 'ct_tag_id' => $tagId,
 406                                         ]
 407                                 );
 408                                 $dbw->delete( 'change_tag', $conds, __METHOD__ );
 409                                 if ( $dbw->affectedRows() && $wgChangeTagsSchemaMigrationStage > MIGRATION_OLD ) {
 410                                         $dbw->update(
 411                                                 'change_tag_def',
 412                                                 [ 'ctd_count = ctd_count - 1' ],
 413                                                 [ 'ctd_name' => $tag ],
 414                                                 __METHOD__
 415                                         );
 416
 417                                         $dbw->delete(
 418                                                 'change_tag_def',
 419                                                 [ 'ctd_name' => $tag, 'ctd_count' => 0, 'ctd_user_defined' => 0 ],
 420                                                 __METHOD__
 421                                         );
 422                                 }
 423                         }
 424                 }
 425
 426                 self::purgeTagUsageCache();
 427
 428                 Hooks::run( 'ChangeTagsAfterUpdateTags', [ $tagsToAdd, $tagsToRemove, $prevTags,
 429                         $rc_id, $rev_id, $log_id, $params, $rc, $user ] );
 430
 431                 return [ $tagsToAdd, $tagsToRemove, $prevTags ];
 432         }
 433
 434         /**
 435          * Adds or removes a given set of tags to/from the relevant row of the
 436          * tag_summary table. Modifies the tagsToAdd and tagsToRemove arrays to
 437          * reflect the tags that were actually added and/or removed.
 438          *
 439          * @param array &$tagsToAdd
 440          * @param array &$tagsToRemove If a tag is present in both $tagsToAdd and
 441          * $tagsToRemove, it will be removed
 442          * @param int|null $rc_id Null if not known or not applicable
 443          * @param int|null $rev_id Null if not known or not applicable
 444          * @param int|null $log_id Null if not known or not applicable
 445          * @param array &$prevTags Optionally outputs a list of the tags that were
 446          * in the tag_summary row to begin with
 447          * @return bool True if any modifications were made, otherwise false
 448          * @since 1.25
 449          */
 450         protected static function updateTagSummaryRow( &$tagsToAdd, &$tagsToRemove,
 451                 $rc_id, $rev_id, $log_id, &$prevTags = []
 452         ) {
 453                 $dbw = wfGetDB( DB_MASTER );
 454
 455                 $tsConds = array_filter( [
 456                         'ts_rc_id' => $rc_id,
 457                         'ts_rev_id' => $rev_id,
 458                         'ts_log_id' => $log_id
 459                 ] );
 460
 461                 // Can't both add and remove a tag at the same time...
 462                 $tagsToAdd = array_diff( $tagsToAdd, $tagsToRemove );
 463
 464                 // Update the summary row.
 465                 // $prevTags can be out of date on replica DBs, especially when addTags is called consecutively,
 466                 // causing loss of tags added recently in tag_summary table.
 467                 $prevTags = $dbw->selectField( 'tag_summary', 'ts_tags', $tsConds, __METHOD__ );
 468                 $prevTags = $prevTags ?: '';
 469                 $prevTags = array_filter( explode( ',', $prevTags ) );
 470
 471                 // add tags
 472                 $tagsToAdd = array_values( array_diff( $tagsToAdd, $prevTags ) );
 473                 $newTags = array_unique( array_merge( $prevTags, $tagsToAdd ) );
 474
 475                 // remove tags
 476                 $tagsToRemove = array_values( array_intersect( $tagsToRemove, $newTags ) );
 477                 $newTags = array_values( array_diff( $newTags, $tagsToRemove ) );
 478
 479                 sort( $prevTags );
 480                 sort( $newTags );
 481                 if ( $prevTags == $newTags ) {
 482                         return false;
 483                 }
 484
 485                 if ( !$newTags ) {
 486                         // No tags left, so delete the row altogether
 487                         $dbw->delete( 'tag_summary', $tsConds, __METHOD__ );
 488                 } else {
 489                         // Specify the non-DEFAULT value columns in the INSERT/REPLACE clause
 490                         $row = array_filter( [ 'ts_tags' => implode( ',', $newTags ) ] + $tsConds );
 491                         // Check the unique keys for conflicts, ignoring any NULL *_id values
 492                         $uniqueKeys = [];
 493                         foreach ( [ 'ts_rev_id', 'ts_rc_id', 'ts_log_id' ] as $uniqueColumn ) {
 494                                 if ( isset( $row[$uniqueColumn] ) ) {
 495                                         $uniqueKeys[] = [ $uniqueColumn ];
 496                                 }
 497                         }
 498
 499                         $dbw->replace( 'tag_summary', $uniqueKeys, $row, __METHOD__ );
 500                 }
 501
 502                 return true;
 503         }
 504
 505         /**
 506          * Helper function to generate a fatal status with a 'not-allowed' type error.
 507          *
 508          * @param string $msgOne Message key to use in the case of one tag
 509          * @param string $msgMulti Message key to use in the case of more than one tag
 510          * @param array $tags Restricted tags (passed as $1 into the message, count of
 511          * $tags passed as $2)
 512          * @return Status
 513          * @since 1.25
 514          */
 515         protected static function restrictedTagError( $msgOne, $msgMulti, $tags ) {
 516                 $lang = RequestContext::getMain()->getLanguage();
 517                 $count = count( $tags );
 518                 return Status::newFatal( ( $count > 1 ) ? $msgMulti : $msgOne,
 519                         $lang->commaList( $tags ), $count );
 520         }
 521
 522         /**
 523          * Is it OK to allow the user to apply all the specified tags at the same time
 524          * as they edit/make the change?
 525          *
 526          * Extensions should not use this function, unless directly handling a user
 527          * request to add a tag to a revision or log entry that the user is making.
 528          *
 529          * @param array $tags Tags that you are interested in applying
 530          * @param User|null $user User whose permission you wish to check, or null to
 531          * check for a generic non-blocked user with the relevant rights
 532          * @return Status
 533          * @since 1.25
 534          */
 535         public static function canAddTagsAccompanyingChange( array $tags, User $user = null ) {
 536                 if ( !is_null( $user ) ) {
 537                         if ( !$user->isAllowed( 'applychangetags' ) ) {
 538                                 return Status::newFatal( 'tags-apply-no-permission' );
 539                         } elseif ( $user->isBlocked() ) {
 540                                 return Status::newFatal( 'tags-apply-blocked', $user->getName() );
 541                         }
 542                 }
 543
 544                 // to be applied, a tag has to be explicitly defined
 545                 $allowedTags = self::listExplicitlyDefinedTags();
 546                 Hooks::run( 'ChangeTagsAllowedAdd', [ &$allowedTags, $tags, $user ] );
 547                 $disallowedTags = array_diff( $tags, $allowedTags );
 548                 if ( $disallowedTags ) {
 549                         return self::restrictedTagError( 'tags-apply-not-allowed-one',
 550                                 'tags-apply-not-allowed-multi', $disallowedTags );
 551                 }
 552
 553                 return Status::newGood();
 554         }
 555
 556         /**
 557          * Adds tags to a given change, checking whether it is allowed first, but
 558          * without adding a log entry. Useful for cases where the tag is being added
 559          * along with the action that generated the change (e.g. tagging an edit as
 560          * it is being made).
 561          *
 562          * Extensions should not use this function, unless directly handling a user
 563          * request to add a particular tag. Normally, extensions should call
 564          * ChangeTags::updateTags() instead.
 565          *
 566          * @param array $tags Tags to apply
 567          * @param int|null $rc_id The rc_id of the change to add the tags to
 568          * @param int|null $rev_id The rev_id of the change to add the tags to
 569          * @param int|null $log_id The log_id of the change to add the tags to
 570          * @param string $params Params to put in the ct_params field of table
 571          * 'change_tag' when adding tags
 572          * @param User $user Who to give credit for the action
 573          * @return Status
 574          * @since 1.25
 575          */
 576         public static function addTagsAccompanyingChangeWithChecks(
 577                 array $tags, $rc_id, $rev_id, $log_id, $params, User $user
 578         ) {
 579                 // are we allowed to do this?
 580                 $result = self::canAddTagsAccompanyingChange( $tags, $user );
 581                 if ( !$result->isOK() ) {
 582                         $result->value = null;
 583                         return $result;
 584                 }
 585
 586                 // do it!
 587                 self::addTags( $tags, $rc_id, $rev_id, $log_id, $params );
 588
 589                 return Status::newGood( true );
 590         }
 591
 592         /**
 593          * Is it OK to allow the user to adds and remove the given tags tags to/from a
 594          * change?
 595          *
 596          * Extensions should not use this function, unless directly handling a user
 597          * request to add or remove tags from an existing revision or log entry.
 598          *
 599          * @param array $tagsToAdd Tags that you are interested in adding
 600          * @param array $tagsToRemove Tags that you are interested in removing
 601          * @param User|null $user User whose permission you wish to check, or null to
 602          * check for a generic non-blocked user with the relevant rights
 603          * @return Status
 604          * @since 1.25
 605          */
 606         public static function canUpdateTags( array $tagsToAdd, array $tagsToRemove,
 607                 User $user = null
 608         ) {
 609                 if ( !is_null( $user ) ) {
 610                         if ( !$user->isAllowed( 'changetags' ) ) {
 611                                 return Status::newFatal( 'tags-update-no-permission' );
 612                         } elseif ( $user->isBlocked() ) {
 613                                 return Status::newFatal( 'tags-update-blocked', $user->getName() );
 614                         }
 615                 }
 616
 617                 if ( $tagsToAdd ) {
 618                         // to be added, a tag has to be explicitly defined
 619                         // @todo Allow extensions to define tags that can be applied by users...
 620                         $explicitlyDefinedTags = self::listExplicitlyDefinedTags();
 621                         $diff = array_diff( $tagsToAdd, $explicitlyDefinedTags );
 622                         if ( $diff ) {
 623                                 return self::restrictedTagError( 'tags-update-add-not-allowed-one',
 624                                         'tags-update-add-not-allowed-multi', $diff );
 625                         }
 626                 }
 627
 628                 if ( $tagsToRemove ) {
 629                         // to be removed, a tag must not be defined by an extension, or equivalently it
 630                         // has to be either explicitly defined or not defined at all
 631                         // (assuming no edge case of a tag both explicitly-defined and extension-defined)
 632                         $softwareDefinedTags = self::listSoftwareDefinedTags();
 633                         $intersect = array_intersect( $tagsToRemove, $softwareDefinedTags );
 634                         if ( $intersect ) {
 635                                 return self::restrictedTagError( 'tags-update-remove-not-allowed-one',
 636                                         'tags-update-remove-not-allowed-multi', $intersect );
 637                         }
 638                 }
 639
 640                 return Status::newGood();
 641         }
 642
 643         /**
 644          * Adds and/or removes tags to/from a given change, checking whether it is
 645          * allowed first, and adding a log entry afterwards.
 646          *
 647          * Includes a call to ChangeTags::canUpdateTags(), so your code doesn't need
 648          * to do that. However, it doesn't check whether the *_id parameters are a
 649          * valid combination. That is up to you to enforce. See ApiTag::execute() for
 650          * an example.
 651          *
 652          * Extensions should generally avoid this function. Call
 653          * ChangeTags::updateTags() instead, unless directly handling a user request
 654          * to add or remove tags from an existing revision or log entry.
 655          *
 656          * @param array|null $tagsToAdd If none, pass array() or null
 657          * @param array|null $tagsToRemove If none, pass array() or null
 658          * @param int|null $rc_id The rc_id of the change to add the tags to
 659          * @param int|null $rev_id The rev_id of the change to add the tags to
 660          * @param int|null $log_id The log_id of the change to add the tags to
 661          * @param string $params Params to put in the ct_params field of table
 662          * 'change_tag' when adding tags
 663          * @param string $reason Comment for the log
 664          * @param User $user Who to give credit for the action
 665          * @return Status If successful, the value of this Status object will be an
 666          * object (stdClass) with the following fields:
 667          *  - logId: the ID of the added log entry, or null if no log entry was added
 668          *    (i.e. no operation was performed)
 669          *  - addedTags: an array containing the tags that were actually added
 670          *  - removedTags: an array containing the tags that were actually removed
 671          * @since 1.25
 672          */
 673         public static function updateTagsWithChecks( $tagsToAdd, $tagsToRemove,
 674                 $rc_id, $rev_id, $log_id, $params, $reason, User $user
 675         ) {
 676                 if ( is_null( $tagsToAdd ) ) {
 677                         $tagsToAdd = [];
 678                 }
 679                 if ( is_null( $tagsToRemove ) ) {
 680                         $tagsToRemove = [];
 681                 }
 682                 if ( !$tagsToAdd && !$tagsToRemove ) {
 683                         // no-op, don't bother
 684                         return Status::newGood( (object)[
 685                                 'logId' => null,
 686                                 'addedTags' => [],
 687                                 'removedTags' => [],
 688                         ] );
 689                 }
 690
 691                 // are we allowed to do this?
 692                 $result = self::canUpdateTags( $tagsToAdd, $tagsToRemove, $user );
 693                 if ( !$result->isOK() ) {
 694                         $result->value = null;
 695                         return $result;
 696                 }
 697
 698                 // basic rate limiting
 699                 if ( $user->pingLimiter( 'changetag' ) ) {
 700                         return Status::newFatal( 'actionthrottledtext' );
 701                 }
 702
 703                 // do it!
 704                 list( $tagsAdded, $tagsRemoved, $initialTags ) = self::updateTags( $tagsToAdd,
 705                         $tagsToRemove, $rc_id, $rev_id, $log_id, $params, null, $user );
 706                 if ( !$tagsAdded && !$tagsRemoved ) {
 707                         // no-op, don't log it
 708                         return Status::newGood( (object)[
 709                                 'logId' => null,
 710                                 'addedTags' => [],
 711                                 'removedTags' => [],
 712                         ] );
 713                 }
 714
 715                 // log it
 716                 $logEntry = new ManualLogEntry( 'tag', 'update' );
 717                 $logEntry->setPerformer( $user );
 718                 $logEntry->setComment( $reason );
 719
 720                 // find the appropriate target page
 721                 if ( $rev_id ) {
 722                         $rev = Revision::newFromId( $rev_id );
 723                         if ( $rev ) {
 724                                 $logEntry->setTarget( $rev->getTitle() );
 725                         }
 726                 } elseif ( $log_id ) {
 727                         // This function is from revision deletion logic and has nothing to do with
 728                         // change tags, but it appears to be the only other place in core where we
 729                         // perform logged actions on log items.
 730                         $logEntry->setTarget( RevDelLogList::suggestTarget( null, [ $log_id ] ) );
 731                 }
 732
 733                 if ( !$logEntry->getTarget() ) {
 734                         // target is required, so we have to set something
 735                         $logEntry->setTarget( SpecialPage::getTitleFor( 'Tags' ) );
 736                 }
 737
 738                 $logParams = [
 739                         '4::revid' => $rev_id,
 740                         '5::logid' => $log_id,
 741                         '6:list:tagsAdded' => $tagsAdded,
 742                         '7:number:tagsAddedCount' => count( $tagsAdded ),
 743                         '8:list:tagsRemoved' => $tagsRemoved,
 744                         '9:number:tagsRemovedCount' => count( $tagsRemoved ),
 745                         'initialTags' => $initialTags,
 746                 ];
 747                 $logEntry->setParameters( $logParams );
 748                 $logEntry->setRelations( [ 'Tag' => array_merge( $tagsAdded, $tagsRemoved ) ] );
 749
 750                 $dbw = wfGetDB( DB_MASTER );
 751                 $logId = $logEntry->insert( $dbw );
 752                 // Only send this to UDP, not RC, similar to patrol events
 753                 $logEntry->publish( $logId, 'udp' );
 754
 755                 return Status::newGood( (object)[
 756                         'logId' => $logId,
 757                         'addedTags' => $tagsAdded,
 758                         'removedTags' => $tagsRemoved,
 759                 ] );
 760         }
 761
 762         /**
 763          * Applies all tags-related changes to a query.
 764          * Handles selecting tags, and filtering.
 765          * Needs $tables to be set up properly, so we can figure out which join conditions to use.
 766          *
 767          * WARNING: If $filter_tag contains more than one tag, this function will add DISTINCT,
 768          * which may cause performance problems for your query unless you put the ID field of your
 769          * table at the end of the ORDER BY, and set a GROUP BY equal to the ORDER BY. For example,
 770          * if you had ORDER BY foo_timestamp DESC, you will now need GROUP BY foo_timestamp, foo_id
 771          * ORDER BY foo_timestamp DESC, foo_id DESC.
 772          *
 773          * @param string|array &$tables Table names, see Database::select
 774          * @param string|array &$fields Fields used in query, see Database::select
 775          * @param string|array &$conds Conditions used in query, see Database::select
 776          * @param array &$join_conds Join conditions, see Database::select
 777          * @param string|array &$options Options, see Database::select
 778          * @param string|array $filter_tag Tag(s) to select on
 779          *
 780          * @throws MWException When unable to determine appropriate JOIN condition for tagging
 781          */
 782         public static function modifyDisplayQuery( &$tables, &$fields, &$conds,
 783                 &$join_conds, &$options, $filter_tag = ''
 784         ) {
 785                 global $wgUseTagFilter, $wgChangeTagsSchemaMigrationStage;
 786
 787                 // Normalize to arrays
 788                 $tables = (array)$tables;
 789                 $fields = (array)$fields;
 790                 $conds = (array)$conds;
 791                 $options = (array)$options;
 792
 793                 // Figure out which ID field to use
 794                 if ( in_array( 'recentchanges', $tables ) ) {
 795                         $join_cond = 'ct_rc_id=rc_id';
 796                 } elseif ( in_array( 'logging', $tables ) ) {
 797                         $join_cond = 'ct_log_id=log_id';
 798                 } elseif ( in_array( 'revision', $tables ) ) {
 799                         $join_cond = 'ct_rev_id=rev_id';
 800                 } elseif ( in_array( 'archive', $tables ) ) {
 801                         $join_cond = 'ct_rev_id=ar_rev_id';
 802                 } else {
 803                         throw new MWException( 'Unable to determine appropriate JOIN condition for tagging.' );
 804                 }
 805
 806                 $tagTables[] = 'change_tag';
 807                 if ( $wgChangeTagsSchemaMigrationStage > MIGRATION_WRITE_BOTH ) {
 808                         $tagTables[] = 'change_tag_def';
 809                         $join_cond_ts_tags = [ $join_cond, 'ct_tag_id=ctd_id' ];
 810                         $field = 'ctd_name';
 811                 } else {
 812                         $field = 'ct_tag';
 813                         $join_cond_ts_tags = $join_cond;
 814                 }
 815
 816                 $fields['ts_tags'] = wfGetDB( DB_REPLICA )->buildGroupConcatField(
 817                         ',', $tagTables, $field, $join_cond_ts_tags
 818                 );
 819
 820                 if ( $wgUseTagFilter && $filter_tag ) {
 821                         // Somebody wants to filter on a tag.
 822                         // Add an INNER JOIN on change_tag
 823
 824                         $tables[] = 'change_tag';
 825                         $join_conds['change_tag'] = [ 'INNER JOIN', $join_cond ];
 826                         if ( $wgChangeTagsSchemaMigrationStage > MIGRATION_WRITE_BOTH ) {
 827                                 $filterTagIds = [];
 828                                 $changeTagDefStore = MediaWikiServices::getInstance()->getChangeTagDefStore();
 829                                 foreach ( (array)$filter_tag as $filterTagName ) {
 830                                         try {
 831                                                 $filterTagIds[] = $changeTagDefStore->getId( $filterTagName );
 832                                         } catch ( NameTableAccessException $exception ) {
 833                                                 // Return nothing.
 834                                                 $conds[] = '0';
 835                                                 break;
 836                                         };
 837                                 }
 838                                 $conds['ct_tag_id'] = $filterTagIds;
 839                         } else {
 840                                 $conds['ct_tag'] = $filter_tag;
 841                         }
 842
 843                         if (
 844                                 is_array( $filter_tag ) && count( $filter_tag ) > 1 &&
 845                                 !in_array( 'DISTINCT', $options )
 846                         ) {
 847                                 $options[] = 'DISTINCT';
 848                         }
 849                 }
 850         }
 851
 852         /**
 853          * Build a text box to select a change tag
 854          *
 855          * @param string $selected Tag to select by default
 856          * @param bool $ooui Use an OOUI TextInputWidget as selector instead of a non-OOUI input field
 857          *        You need to call OutputPage::enableOOUI() yourself.
 858          * @param IContextSource|null $context
 859          * @note Even though it takes null as a valid argument, an IContextSource is preferred
 860          *       in a new code, as the null value can change in the future
 861          * @return array an array of (label, selector)
 862          */
 863         public static function buildTagFilterSelector(
 864                 $selected = '', $ooui = false, IContextSource $context = null
 865         ) {
 866                 if ( !$context ) {
 867                         $context = RequestContext::getMain();
 868                 }
 869
 870                 $config = $context->getConfig();
 871                 if ( !$config->get( 'UseTagFilter' ) || !count( self::listDefinedTags() ) ) {
 872                         return [];
 873                 }
 874
 875                 $data = [
 876                         Html::rawElement(
 877                                 'label',
 878                                 [ 'for' => 'tagfilter' ],
 879                                 $context->msg( 'tag-filter' )->parse()
 880                         )
 881                 ];
 882
 883                 if ( $ooui ) {
 884                         $data[] = new OOUI\TextInputWidget( [
 885                                 'id' => 'tagfilter',
 886                                 'name' => 'tagfilter',
 887                                 'value' => $selected,
 888                                 'classes' => 'mw-tagfilter-input',
 889                         ] );
 890                 } else {
 891                         $data[] = Xml::input(
 892                                 'tagfilter',
 893                                 20,
 894                                 $selected,
 895                                 [ 'class' => 'mw-tagfilter-input mw-ui-input mw-ui-input-inline', 'id' => 'tagfilter' ]
 896                         );
 897                 }
 898
 899                 return $data;
 900         }
 901
 902         /**
 903          * Defines a tag in the valid_tag table and/or update ctd_user_defined field in change_tag_def,
 904          * without checking that the tag name is valid.
 905          * Extensions should NOT use this function; they can use the ListDefinedTags
 906          * hook instead.
 907          *
 908          * @param string $tag Tag to create
 909          * @since 1.25
 910          */
 911         public static function defineTag( $tag ) {
 912                 global $wgChangeTagsSchemaMigrationStage;
 913
 914                 $dbw = wfGetDB( DB_MASTER );
 915                 if ( $wgChangeTagsSchemaMigrationStage > MIGRATION_OLD ) {
 916                         $tagDef = [
 917                                 'ctd_name' => $tag,
 918                                 'ctd_user_defined' => 1,
 919                                 'ctd_count' => 0
 920                         ];
 921                         $dbw->upsert(
 922                                 'change_tag_def',
 923                                 $tagDef,
 924                                 [ 'ctd_name' ],
 925                                 [ 'ctd_user_defined' => 1 ],
 926                                 __METHOD__
 927                         );
 928                 }
 929
 930                 $dbw->replace(
 931                         'valid_tag',
 932                         [ 'vt_tag' ],
 933                         [ 'vt_tag' => $tag ],
 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                 global $wgChangeTagsSchemaMigrationStage;
 951
 952                 $dbw = wfGetDB( DB_MASTER );
 953
 954                 if ( $wgChangeTagsSchemaMigrationStage > MIGRATION_OLD ) {
 955                         $dbw->update(
 956                                 'change_tag_def',
 957                                 [ 'ctd_user_defined' => 0 ],
 958                                 [ 'ctd_name' => $tag ],
 959                                 __METHOD__
 960                         );
 961
 962                         $dbw->delete(
 963                                 'change_tag_def',
 964                                 [ 'ctd_name' => $tag, 'ctd_count' => 0 ],
 965                                 __METHOD__
 966                         );
 967                 }
 968
 969                 $dbw->delete( 'valid_tag', [ 'vt_tag' => $tag ], __METHOD__ );
 970
 971                 // clear the memcache of defined tags
 972                 self::purgeTagCacheAll();
 973         }
 974
 975         /**
 976          * Writes a tag action into the tag management log.
 977          *
 978          * @param string $action
 979          * @param string $tag
 980          * @param string $reason
 981          * @param User $user Who to attribute the action to
 982          * @param int|null $tagCount For deletion only, how many usages the tag had before
 983          * it was deleted.
 984          * @param array $logEntryTags Change tags to apply to the entry
 985          * that will be created in the tag management log
 986          * @return int ID of the inserted log entry
 987          * @since 1.25
 988          */
 989         protected static function logTagManagementAction( $action, $tag, $reason,
 990                 User $user, $tagCount = null, array $logEntryTags = []
 991         ) {
 992                 $dbw = wfGetDB( DB_MASTER );
 993
 994                 $logEntry = new ManualLogEntry( 'managetags', $action );
 995                 $logEntry->setPerformer( $user );
 996                 // target page is not relevant, but it has to be set, so we just put in
 997                 // the title of Special:Tags
 998                 $logEntry->setTarget( Title::newFromText( 'Special:Tags' ) );
 999                 $logEntry->setComment( $reason );
1000
1001                 $params = [ '4::tag' => $tag ];
1002                 if ( !is_null( $tagCount ) ) {
1003                         $params['5:number:count'] = $tagCount;
1004                 }
1005                 $logEntry->setParameters( $params );
1006                 $logEntry->setRelations( [ 'Tag' => $tag ] );
1007                 $logEntry->setTags( $logEntryTags );
1008
1009                 $logId = $logEntry->insert( $dbw );
1010                 $logEntry->publish( $logId );
1011                 return $logId;
1012         }
1013
1014         /**
1015          * Is it OK to allow the user to activate this tag?
1016          *
1017          * @param string $tag Tag that you are interested in activating
1018          * @param User|null $user User whose permission you wish to check, or null if
1019          * you don't care (e.g. maintenance scripts)
1020          * @return Status
1021          * @since 1.25
1022          */
1023         public static function canActivateTag( $tag, User $user = null ) {
1024                 if ( !is_null( $user ) ) {
1025                         if ( !$user->isAllowed( 'managechangetags' ) ) {
1026                                 return Status::newFatal( 'tags-manage-no-permission' );
1027                         } elseif ( $user->isBlocked() ) {
1028                                 return Status::newFatal( 'tags-manage-blocked', $user->getName() );
1029                         }
1030                 }
1031
1032                 // defined tags cannot be activated (a defined tag is either extension-
1033                 // defined, in which case the extension chooses whether or not to active it;
1034                 // or user-defined, in which case it is considered active)
1035                 $definedTags = self::listDefinedTags();
1036                 if ( in_array( $tag, $definedTags ) ) {
1037                         return Status::newFatal( 'tags-activate-not-allowed', $tag );
1038                 }
1039
1040                 // non-existing tags cannot be activated
1041                 $tagUsage = self::tagUsageStatistics();
1042                 if ( !isset( $tagUsage[$tag] ) ) { // we already know the tag is undefined
1043                         return Status::newFatal( 'tags-activate-not-found', $tag );
1044                 }
1045
1046                 return Status::newGood();
1047         }
1048
1049         /**
1050          * Activates a tag, checking whether it is allowed first, and adding a log
1051          * entry afterwards.
1052          *
1053          * Includes a call to ChangeTag::canActivateTag(), so your code doesn't need
1054          * to do that.
1055          *
1056          * @param string $tag
1057          * @param string $reason
1058          * @param User $user Who to give credit for the action
1059          * @param bool $ignoreWarnings Can be used for API interaction, default false
1060          * @param array $logEntryTags Change tags to apply to the entry
1061          * that will be created in the tag management log
1062          * @return Status If successful, the Status contains the ID of the added log
1063          * entry as its value
1064          * @since 1.25
1065          */
1066         public static function activateTagWithChecks( $tag, $reason, User $user,
1067                 $ignoreWarnings = false, array $logEntryTags = []
1068         ) {
1069                 // are we allowed to do this?
1070                 $result = self::canActivateTag( $tag, $user );
1071                 if ( $ignoreWarnings ? !$result->isOK() : !$result->isGood() ) {
1072                         $result->value = null;
1073                         return $result;
1074                 }
1075
1076                 // do it!
1077                 self::defineTag( $tag );
1078
1079                 // log it
1080                 $logId = self::logTagManagementAction( 'activate', $tag, $reason, $user,
1081                         null, $logEntryTags );
1082
1083                 return Status::newGood( $logId );
1084         }
1085
1086         /**
1087          * Is it OK to allow the user to deactivate this tag?
1088          *
1089          * @param string $tag Tag that you are interested in deactivating
1090          * @param User|null $user User whose permission you wish to check, or null if
1091          * you don't care (e.g. maintenance scripts)
1092          * @return Status
1093          * @since 1.25
1094          */
1095         public static function canDeactivateTag( $tag, User $user = null ) {
1096                 if ( !is_null( $user ) ) {
1097                         if ( !$user->isAllowed( 'managechangetags' ) ) {
1098                                 return Status::newFatal( 'tags-manage-no-permission' );
1099                         } elseif ( $user->isBlocked() ) {
1100                                 return Status::newFatal( 'tags-manage-blocked', $user->getName() );
1101                         }
1102                 }
1103
1104                 // only explicitly-defined tags can be deactivated
1105                 $explicitlyDefinedTags = self::listExplicitlyDefinedTags();
1106                 if ( !in_array( $tag, $explicitlyDefinedTags ) ) {
1107                         return Status::newFatal( 'tags-deactivate-not-allowed', $tag );
1108                 }
1109                 return Status::newGood();
1110         }
1111
1112         /**
1113          * Deactivates a tag, checking whether it is allowed first, and adding a log
1114          * entry afterwards.
1115          *
1116          * Includes a call to ChangeTag::canDeactivateTag(), so your code doesn't need
1117          * to do that.
1118          *
1119          * @param string $tag
1120          * @param string $reason
1121          * @param User $user Who to give credit for the action
1122          * @param bool $ignoreWarnings Can be used for API interaction, default false
1123          * @param array $logEntryTags Change tags to apply to the entry
1124          * that will be created in the tag management log
1125          * @return Status If successful, the Status contains the ID of the added log
1126          * entry as its value
1127          * @since 1.25
1128          */
1129         public static function deactivateTagWithChecks( $tag, $reason, User $user,
1130                 $ignoreWarnings = false, array $logEntryTags = []
1131         ) {
1132                 // are we allowed to do this?
1133                 $result = self::canDeactivateTag( $tag, $user );
1134                 if ( $ignoreWarnings ? !$result->isOK() : !$result->isGood() ) {
1135                         $result->value = null;
1136                         return $result;
1137                 }
1138
1139                 // do it!
1140                 self::undefineTag( $tag );
1141
1142                 // log it
1143                 $logId = self::logTagManagementAction( 'deactivate', $tag, $reason, $user,
1144                         null, $logEntryTags );
1145
1146                 return Status::newGood( $logId );
1147         }
1148
1149         /**
1150          * Is the tag name valid?
1151          *
1152          * @param string $tag Tag that you are interested in creating
1153          * @return Status
1154          * @since 1.30
1155          */
1156         public static function isTagNameValid( $tag ) {
1157                 // no empty tags
1158                 if ( $tag === '' ) {
1159                         return Status::newFatal( 'tags-create-no-name' );
1160                 }
1161
1162                 // tags cannot contain commas (used as a delimiter in tag_summary table),
1163                 // pipe (used as a delimiter between multiple tags in
1164                 // SpecialRecentchanges and friends), or slashes (would break tag description messages in
1165                 // MediaWiki namespace)
1166                 if ( strpos( $tag, ',' ) !== false || strpos( $tag, '|' ) !== false
1167                         || strpos( $tag, '/' ) !== false ) {
1168                         return Status::newFatal( 'tags-create-invalid-chars' );
1169                 }
1170
1171                 // could the MediaWiki namespace description messages be created?
1172                 $title = Title::makeTitleSafe( NS_MEDIAWIKI, "Tag-$tag-description" );
1173                 if ( is_null( $title ) ) {
1174                         return Status::newFatal( 'tags-create-invalid-title-chars' );
1175                 }
1176
1177                 return Status::newGood();
1178         }
1179
1180         /**
1181          * Is it OK to allow the user to create this tag?
1182          *
1183          * Extensions should NOT use this function. In most cases, a tag can be
1184          * defined using the ListDefinedTags hook without any checking.
1185          *
1186          * @param string $tag Tag that you are interested in creating
1187          * @param User|null $user User whose permission you wish to check, or null if
1188          * you don't care (e.g. maintenance scripts)
1189          * @return Status
1190          * @since 1.25
1191          */
1192         public static function canCreateTag( $tag, User $user = null ) {
1193                 if ( !is_null( $user ) ) {
1194                         if ( !$user->isAllowed( 'managechangetags' ) ) {
1195                                 return Status::newFatal( 'tags-manage-no-permission' );
1196                         } elseif ( $user->isBlocked() ) {
1197                                 return Status::newFatal( 'tags-manage-blocked', $user->getName() );
1198                         }
1199                 }
1200
1201                 $status = self::isTagNameValid( $tag );
1202                 if ( !$status->isGood() ) {
1203                         return $status;
1204                 }
1205
1206                 // does the tag already exist?
1207                 $tagUsage = self::tagUsageStatistics();
1208                 if ( isset( $tagUsage[$tag] ) || in_array( $tag, self::listDefinedTags() ) ) {
1209                         return Status::newFatal( 'tags-create-already-exists', $tag );
1210                 }
1211
1212                 // check with hooks
1213                 $canCreateResult = Status::newGood();
1214                 Hooks::run( 'ChangeTagCanCreate', [ $tag, $user, &$canCreateResult ] );
1215                 return $canCreateResult;
1216         }
1217
1218         /**
1219          * Creates a tag by adding a row to the `valid_tag` table.
1220          * and/or add it to `change_tag_def` table.
1221          *
1222          * Extensions should NOT use this function; they can use the ListDefinedTags
1223          * hook instead.
1224          *
1225          * Includes a call to ChangeTag::canCreateTag(), so your code doesn't need to
1226          * do that.
1227          *
1228          * @param string $tag
1229          * @param string $reason
1230          * @param User $user Who to give credit for the action
1231          * @param bool $ignoreWarnings Can be used for API interaction, default false
1232          * @param array $logEntryTags Change tags to apply to the entry
1233          * that will be created in the tag management log
1234          * @return Status If successful, the Status contains the ID of the added log
1235          * entry as its value
1236          * @since 1.25
1237          */
1238         public static function createTagWithChecks( $tag, $reason, User $user,
1239                 $ignoreWarnings = false, array $logEntryTags = []
1240         ) {
1241                 // are we allowed to do this?
1242                 $result = self::canCreateTag( $tag, $user );
1243                 if ( $ignoreWarnings ? !$result->isOK() : !$result->isGood() ) {
1244                         $result->value = null;
1245                         return $result;
1246                 }
1247
1248                 // do it!
1249                 self::defineTag( $tag );
1250
1251                 // log it
1252                 $logId = self::logTagManagementAction( 'create', $tag, $reason, $user,
1253                         null, $logEntryTags );
1254
1255                 return Status::newGood( $logId );
1256         }
1257
1258         /**
1259          * Permanently removes all traces of a tag from the DB. Good for removing
1260          * misspelt or temporary tags.
1261          *
1262          * This function should be directly called by maintenance scripts only, never
1263          * by user-facing code. See deleteTagWithChecks() for functionality that can
1264          * safely be exposed to users.
1265          *
1266          * @param string $tag Tag to remove
1267          * @return Status The returned status will be good unless a hook changed it
1268          * @since 1.25
1269          */
1270         public static function deleteTagEverywhere( $tag ) {
1271                 global $wgChangeTagsSchemaMigrationStage;
1272                 $dbw = wfGetDB( DB_MASTER );
1273                 $dbw->startAtomic( __METHOD__ );
1274
1275                 // delete from valid_tag and/or set ctd_user_defined = 0
1276                 self::undefineTag( $tag );
1277
1278                 if ( $wgChangeTagsSchemaMigrationStage > MIGRATION_WRITE_BOTH ) {
1279                         $tagId = MediaWikiServices::getInstance()->getChangeTagDefStore()->getId( $tag );
1280                         $conditions = [ 'ct_tag_id' => $tagId ];
1281                 } else {
1282                         $conditions = [ 'ct_tag' => $tag ];
1283                 }
1284
1285                 // find out which revisions use this tag, so we can delete from tag_summary
1286                 $result = $dbw->select( 'change_tag',
1287                         [ 'ct_rc_id', 'ct_log_id', 'ct_rev_id' ],
1288                         $conditions,
1289                         __METHOD__ );
1290                 foreach ( $result as $row ) {
1291                         // remove the tag from the relevant row of tag_summary
1292                         $tagsToAdd = [];
1293                         $tagsToRemove = [ $tag ];
1294                         self::updateTagSummaryRow( $tagsToAdd, $tagsToRemove, $row->ct_rc_id,
1295                                 $row->ct_rev_id, $row->ct_log_id );
1296                 }
1297
1298                 // delete from change_tag
1299                 if ( $wgChangeTagsSchemaMigrationStage > MIGRATION_WRITE_BOTH ) {
1300                         $tagId = MediaWikiServices::getInstance()->getChangeTagDefStore()->getId( $tag );
1301                         $dbw->delete( 'change_tag', [ 'ct_tag_id' => $tagId ], __METHOD__ );
1302                 } else {
1303                         $dbw->delete( 'change_tag', [ 'ct_tag' => $tag ], __METHOD__ );
1304                 }
1305
1306                 if ( $wgChangeTagsSchemaMigrationStage > MIGRATION_OLD ) {
1307                         $dbw->delete( 'change_tag_def', [ 'ctd_name' => $tag ], __METHOD__ );
1308                 }
1309
1310                 $dbw->endAtomic( __METHOD__ );
1311
1312                 // give extensions a chance
1313                 $status = Status::newGood();
1314                 Hooks::run( 'ChangeTagAfterDelete', [ $tag, &$status ] );
1315                 // let's not allow error results, as the actual tag deletion succeeded
1316                 if ( !$status->isOK() ) {
1317                         wfDebug( 'ChangeTagAfterDelete error condition downgraded to warning' );
1318                         $status->setOK( true );
1319                 }
1320
1321                 // clear the memcache of defined tags
1322                 self::purgeTagCacheAll();
1323
1324                 return $status;
1325         }
1326
1327         /**
1328          * Is it OK to allow the user to delete this tag?
1329          *
1330          * @param string $tag Tag that you are interested in deleting
1331          * @param User|null $user User whose permission you wish to check, or null if
1332          * you don't care (e.g. maintenance scripts)
1333          * @return Status
1334          * @since 1.25
1335          */
1336         public static function canDeleteTag( $tag, User $user = null ) {
1337                 $tagUsage = self::tagUsageStatistics();
1338
1339                 if ( !is_null( $user ) ) {
1340                         if ( !$user->isAllowed( 'deletechangetags' ) ) {
1341                                 return Status::newFatal( 'tags-delete-no-permission' );
1342                         } elseif ( $user->isBlocked() ) {
1343                                 return Status::newFatal( 'tags-manage-blocked', $user->getName() );
1344                         }
1345                 }
1346
1347                 if ( !isset( $tagUsage[$tag] ) && !in_array( $tag, self::listDefinedTags() ) ) {
1348                         return Status::newFatal( 'tags-delete-not-found', $tag );
1349                 }
1350
1351                 if ( isset( $tagUsage[$tag] ) && $tagUsage[$tag] > self::MAX_DELETE_USES ) {
1352                         return Status::newFatal( 'tags-delete-too-many-uses', $tag, self::MAX_DELETE_USES );
1353                 }
1354
1355                 $softwareDefined = self::listSoftwareDefinedTags();
1356                 if ( in_array( $tag, $softwareDefined ) ) {
1357                         // extension-defined tags can't be deleted unless the extension
1358                         // specifically allows it
1359                         $status = Status::newFatal( 'tags-delete-not-allowed' );
1360                 } else {
1361                         // user-defined tags are deletable unless otherwise specified
1362                         $status = Status::newGood();
1363                 }
1364
1365                 Hooks::run( 'ChangeTagCanDelete', [ $tag, $user, &$status ] );
1366                 return $status;
1367         }
1368
1369         /**
1370          * Deletes a tag, checking whether it is allowed first, and adding a log entry
1371          * afterwards.
1372          *
1373          * Includes a call to ChangeTag::canDeleteTag(), so your code doesn't need to
1374          * do that.
1375          *
1376          * @param string $tag
1377          * @param string $reason
1378          * @param User $user Who to give credit for the action
1379          * @param bool $ignoreWarnings Can be used for API interaction, default false
1380          * @param array $logEntryTags Change tags to apply to the entry
1381          * that will be created in the tag management log
1382          * @return Status If successful, the Status contains the ID of the added log
1383          * entry as its value
1384          * @since 1.25
1385          */
1386         public static function deleteTagWithChecks( $tag, $reason, User $user,
1387                 $ignoreWarnings = false, array $logEntryTags = []
1388         ) {
1389                 // are we allowed to do this?
1390                 $result = self::canDeleteTag( $tag, $user );
1391                 if ( $ignoreWarnings ? !$result->isOK() : !$result->isGood() ) {
1392                         $result->value = null;
1393                         return $result;
1394                 }
1395
1396                 // store the tag usage statistics
1397                 $tagUsage = self::tagUsageStatistics();
1398                 $hitcount = $tagUsage[$tag] ?? 0;
1399
1400                 // do it!
1401                 $deleteResult = self::deleteTagEverywhere( $tag );
1402                 if ( !$deleteResult->isOK() ) {
1403                         return $deleteResult;
1404                 }
1405
1406                 // log it
1407                 $logId = self::logTagManagementAction( 'delete', $tag, $reason, $user,
1408                         $hitcount, $logEntryTags );
1409
1410                 $deleteResult->value = $logId;
1411                 return $deleteResult;
1412         }
1413
1414         /**
1415          * Lists those tags which core or extensions report as being "active".
1416          *
1417          * @return array
1418          * @since 1.25
1419          */
1420         public static function listSoftwareActivatedTags() {
1421                 // core active tags
1422                 $tags = self::getSoftwareTags();
1423                 if ( !Hooks::isRegistered( 'ChangeTagsListActive' ) ) {
1424                         return $tags;
1425                 }
1426                 $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
1427                 return $cache->getWithSetCallback(
1428                         $cache->makeKey( 'active-tags' ),
1429                         WANObjectCache::TTL_MINUTE * 5,
1430                         function ( $oldValue, &$ttl, array &$setOpts ) use ( $tags ) {
1431                                 $setOpts += Database::getCacheSetOptions( wfGetDB( DB_REPLICA ) );
1432
1433                                 // Ask extensions which tags they consider active
1434                                 Hooks::run( 'ChangeTagsListActive', [ &$tags ] );
1435                                 return $tags;
1436                         },
1437                         [
1438                                 'checkKeys' => [ $cache->makeKey( 'active-tags' ) ],
1439                                 'lockTSE' => WANObjectCache::TTL_MINUTE * 5,
1440                                 'pcTTL' => WANObjectCache::TTL_PROC_LONG
1441                         ]
1442                 );
1443         }
1444
1445         /**
1446          * Basically lists defined tags which count even if they aren't applied to anything.
1447          * It returns a union of the results of listExplicitlyDefinedTags()
1448          *
1449          * @return string[] Array of strings: tags
1450          */
1451         public static function listDefinedTags() {
1452                 $tags1 = self::listExplicitlyDefinedTags();
1453                 $tags2 = self::listSoftwareDefinedTags();
1454                 return array_values( array_unique( array_merge( $tags1, $tags2 ) ) );
1455         }
1456
1457         /**
1458          * Lists tags explicitly defined in the `valid_tag` table of the database.
1459          * Tags in table 'change_tag' which are not in table 'valid_tag' are not
1460          * included.
1461          *
1462          * Tries memcached first.
1463          *
1464          * @return string[] Array of strings: tags
1465          * @since 1.25
1466          */
1467         public static function listExplicitlyDefinedTags() {
1468                 $fname = __METHOD__;
1469
1470                 $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
1471                 return $cache->getWithSetCallback(
1472                         $cache->makeKey( 'valid-tags-db' ),
1473                         WANObjectCache::TTL_MINUTE * 5,
1474                         function ( $oldValue, &$ttl, array &$setOpts ) use ( $fname ) {
1475                                 $dbr = wfGetDB( DB_REPLICA );
1476
1477                                 $setOpts += Database::getCacheSetOptions( $dbr );
1478
1479                                 $tags = $dbr->selectFieldValues( 'valid_tag', 'vt_tag', [], $fname );
1480
1481                                 return array_filter( array_unique( $tags ) );
1482                         },
1483                         [
1484                                 'checkKeys' => [ $cache->makeKey( 'valid-tags-db' ) ],
1485                                 'lockTSE' => WANObjectCache::TTL_MINUTE * 5,
1486                                 'pcTTL' => WANObjectCache::TTL_PROC_LONG
1487                         ]
1488                 );
1489         }
1490
1491         /**
1492          * Lists tags defined by core or extensions using the ListDefinedTags hook.
1493          * Extensions need only define those tags they deem to be in active use.
1494          *
1495          * Tries memcached first.
1496          *
1497          * @return string[] Array of strings: tags
1498          * @since 1.25
1499          */
1500         public static function listSoftwareDefinedTags() {
1501                 // core defined tags
1502                 $tags = self::getSoftwareTags( true );
1503                 if ( !Hooks::isRegistered( 'ListDefinedTags' ) ) {
1504                         return $tags;
1505                 }
1506                 $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
1507                 return $cache->getWithSetCallback(
1508                         $cache->makeKey( 'valid-tags-hook' ),
1509                         WANObjectCache::TTL_MINUTE * 5,
1510                         function ( $oldValue, &$ttl, array &$setOpts ) use ( $tags ) {
1511                                 $setOpts += Database::getCacheSetOptions( wfGetDB( DB_REPLICA ) );
1512
1513                                 Hooks::run( 'ListDefinedTags', [ &$tags ] );
1514                                 return array_filter( array_unique( $tags ) );
1515                         },
1516                         [
1517                                 'checkKeys' => [ $cache->makeKey( 'valid-tags-hook' ) ],
1518                                 'lockTSE' => WANObjectCache::TTL_MINUTE * 5,
1519                                 'pcTTL' => WANObjectCache::TTL_PROC_LONG
1520                         ]
1521                 );
1522         }
1523
1524         /**
1525          * Invalidates the short-term cache of defined tags used by the
1526          * list*DefinedTags functions, as well as the tag statistics cache.
1527          * @since 1.25
1528          */
1529         public static function purgeTagCacheAll() {
1530                 $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
1531
1532                 $cache->touchCheckKey( $cache->makeKey( 'active-tags' ) );
1533                 $cache->touchCheckKey( $cache->makeKey( 'valid-tags-db' ) );
1534                 $cache->touchCheckKey( $cache->makeKey( 'valid-tags-hook' ) );
1535
1536                 self::purgeTagUsageCache();
1537         }
1538
1539         /**
1540          * Invalidates the tag statistics cache only.
1541          * @since 1.25
1542          */
1543         public static function purgeTagUsageCache() {
1544                 $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
1545
1546                 $cache->touchCheckKey( $cache->makeKey( 'change-tag-statistics' ) );
1547         }
1548
1549         /**
1550          * Returns a map of any tags used on the wiki to number of edits
1551          * tagged with them, ordered descending by the hitcount.
1552          * This does not include tags defined somewhere that have never been applied.
1553          *
1554          * Keeps a short-term cache in memory, so calling this multiple times in the
1555          * same request should be fine.
1556          *
1557          * @return array Array of string => int
1558          */
1559         public static function tagUsageStatistics() {
1560                 global $wgChangeTagsSchemaMigrationStage, $wgTagStatisticsNewTable;
1561                 if ( $wgChangeTagsSchemaMigrationStage > MIGRATION_WRITE_BOTH ||
1562                         ( $wgTagStatisticsNewTable && $wgChangeTagsSchemaMigrationStage > MIGRATION_OLD )
1563                 ) {
1564                         return self::newTagUsageStatistics();
1565                 }
1566
1567                 $fname = __METHOD__;
1568                 $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
1569                 return $cache->getWithSetCallback(
1570                         $cache->makeKey( 'change-tag-statistics' ),
1571                         WANObjectCache::TTL_MINUTE * 5,
1572                         function ( $oldValue, &$ttl, array &$setOpts ) use ( $fname ) {
1573                                 $dbr = wfGetDB( DB_REPLICA, 'vslow' );
1574
1575                                 $setOpts += Database::getCacheSetOptions( $dbr );
1576
1577                                 $res = $dbr->select(
1578                                         'change_tag',
1579                                         [ 'ct_tag', 'hitcount' => 'count(*)' ],
1580                                         [],
1581                                         $fname,
1582                                         [ 'GROUP BY' => 'ct_tag', 'ORDER BY' => 'hitcount DESC' ]
1583                                 );
1584
1585                                 $out = [];
1586                                 foreach ( $res as $row ) {
1587                                         $out[$row->ct_tag] = $row->hitcount;
1588                                 }
1589
1590                                 return $out;
1591                         },
1592                         [
1593                                 'checkKeys' => [ $cache->makeKey( 'change-tag-statistics' ) ],
1594                                 'lockTSE' => WANObjectCache::TTL_MINUTE * 5,
1595                                 'pcTTL' => WANObjectCache::TTL_PROC_LONG
1596                         ]
1597                 );
1598         }
1599
1600         /**
1601          * Same self::tagUsageStatistics() but uses change_tag_def.
1602          *
1603          * @return array Array of string => int
1604          */
1605         private static function newTagUsageStatistics() {
1606                 $dbr = wfGetDB( DB_REPLICA );
1607                 $res = $dbr->select(
1608                         'change_tag_def',
1609                         [ 'ctd_name', 'ctd_count' ],
1610                         [],
1611                         __METHOD__,
1612                         [ 'ORDER BY' => 'ctd_count DESC' ]
1613                 );
1614
1615                 $out = [];
1616                 foreach ( $res as $row ) {
1617                         $out[$row->ctd_name] = $row->ctd_count;
1618                 }
1619
1620                 return $out;
1621         }
1622
1623         /**
1624          * Indicate whether change tag editing UI is relevant
1625          *
1626          * Returns true if the user has the necessary right and there are any
1627          * editable tags defined.
1628          *
1629          * This intentionally doesn't check "any addable || any deletable", because
1630          * it seems like it would be more confusing than useful if the checkboxes
1631          * suddenly showed up because some abuse filter stopped defining a tag and
1632          * then suddenly disappeared when someone deleted all uses of that tag.
1633          *
1634          * @param User $user
1635          * @return bool
1636          */
1637         public static function showTagEditingUI( User $user ) {
1638                 return $user->isAllowed( 'changetags' ) && (bool)self::listExplicitlyDefinedTags();
1639         }
1640 }