includes/changetags/ChangeTags.php

   1 <?php
   2 /**
   3  * Recent changes tagging.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  * @ingroup Change tagging
  22  */
  23
  24 use MediaWiki\MediaWikiServices;
  25 use Wikimedia\Rdbms\Database;
  26
  27 class ChangeTags {
  28         /**
  29          * Can't delete tags with more than this many uses. Similar in intent to
  30          * the bigdelete user right
  31          * @todo Use the job queue for tag deletion to avoid this restriction
  32          */
  33         const MAX_DELETE_USES = 5000;
  34
  35         /**
  36          * A list of tags defined and used by MediaWiki itself.
  37          */
  38         private static $definedSoftwareTags = [
  39                 'mw-contentmodelchange',
  40                 'mw-new-redirect',
  41                 'mw-removed-redirect',
  42                 'mw-changed-redirect-target',
  43                 'mw-blank',
  44                 'mw-replace',
  45                 'mw-rollback',
  46                 'mw-undo',
  47         ];
  48
  49         /**
  50          * Loads defined core tags, checks for invalid types (if not array),
  51          * and filters for supported and enabled (if $all is false) tags only.
  52          *
  53          * @param bool $all If true, return all valid defined tags. Otherwise, return only enabled ones.
  54          * @return array Array of all defined/enabled tags.
  55          */
  56         public static function getSoftwareTags( $all = false ) {
  57                 global $wgSoftwareTags;
  58                 $softwareTags = [];
  59
  60                 if ( !is_array( $wgSoftwareTags ) ) {
  61                         wfWarn( 'wgSoftwareTags should be associative array of enabled tags.
  62                         Please refer to documentation for the list of tags you can enable' );
  63                         return $softwareTags;
  64                 }
  65
  66                 $availableSoftwareTags = !$all ?
  67                         array_keys( array_filter( $wgSoftwareTags ) ) :
  68                         array_keys( $wgSoftwareTags );
  69
  70                 $softwareTags = array_intersect(
  71                         $availableSoftwareTags,
  72                         self::$definedSoftwareTags
  73                 );
  74
  75                 return $softwareTags;
  76         }
  77
  78         /**
  79          * Creates HTML for the given tags
  80          *
  81          * @param string $tags Comma-separated list of tags
  82          * @param string $page A label for the type of action which is being displayed,
  83          *   for example: 'history', 'contributions' or 'newpages'
  84          * @param IContextSource|null $context
  85          * @note Even though it takes null as a valid argument, an IContextSource is preferred
  86          *       in a new code, as the null value is subject to change in the future
  87          * @return array Array with two items: (html, classes)
  88          *   - html: String: HTML for displaying the tags (empty string when param $tags is empty)
  89          *   - classes: Array of strings: CSS classes used in the generated html, one class for each tag
  90          */
  91         public static function formatSummaryRow( $tags, $page, IContextSource $context = null ) {
  92                 if ( !$tags ) {
  93                         return [ '', [] ];
  94                 }
  95                 if ( !$context ) {
  96                         $context = RequestContext::getMain();
  97                 }
  98
  99                 $classes = [];
 100
 101                 $tags = explode( ',', $tags );
 102                 $displayTags = [];
 103                 foreach ( $tags as $tag ) {
 104                         if ( !$tag ) {
 105                                 continue;
 106                         }
 107                         $description = self::tagDescription( $tag, $context );
 108                         if ( $description === false ) {
 109                                 continue;
 110                         }
 111                         $displayTags[] = Xml::tags(
 112                                 'span',
 113                                 [ 'class' => 'mw-tag-marker ' .
 114                                                                 Sanitizer::escapeClass( "mw-tag-marker-$tag" ) ],
 115                                 $description
 116                         );
 117                         $classes[] = Sanitizer::escapeClass( "mw-tag-$tag" );
 118                 }
 119
 120                 if ( !$displayTags ) {
 121                         return [ '', [] ];
 122                 }
 123
 124                 $markers = $context->msg( 'tag-list-wrapper' )
 125                         ->numParams( count( $displayTags ) )
 126                         ->rawParams( $context->getLanguage()->commaList( $displayTags ) )
 127                         ->parse();
 128                 $markers = Xml::tags( 'span', [ 'class' => 'mw-tag-markers' ], $markers );
 129
 130                 return [ $markers, $classes ];
 131         }
 132
 133         /**
 134          * Get a short description for a tag.
 135          *
 136          * Checks if message key "mediawiki:tag-$tag" exists. If it does not,
 137          * returns the HTML-escaped tag name. Uses the message if the message
 138          * exists, provided it is not disabled. If the message is disabled,
 139          * we consider the tag hidden, and return false.
 140          *
 141          * @param string $tag
 142          * @param IContextSource $context
 143          * @return string|bool Tag description or false if tag is to be hidden.
 144          * @since 1.25 Returns false if tag is to be hidden.
 145          */
 146         public static function tagDescription( $tag, IContextSource $context ) {
 147                 $msg = $context->msg( "tag-$tag" );
 148                 if ( !$msg->exists() ) {
 149                         // No such message, so return the HTML-escaped tag name.
 150                         return htmlspecialchars( $tag );
 151                 }
 152                 if ( $msg->isDisabled() ) {
 153                         // The message exists but is disabled, hide the tag.
 154                         return false;
 155                 }
 156
 157                 // Message exists and isn't disabled, use it.
 158                 return $msg->parse();
 159         }
 160
 161         /**
 162          * Get the message object for the tag's long description.
 163          *
 164          * Checks if message key "mediawiki:tag-$tag-description" exists. If it does not,
 165          * or if message is disabled, returns false. Otherwise, returns the message object
 166          * for the long description.
 167          *
 168          * @param string $tag
 169          * @param IContextSource $context
 170          * @return Message|bool Message object of the tag long description or false if
 171          *  there is no description.
 172          */
 173         public static function tagLongDescriptionMessage( $tag, IContextSource $context ) {
 174                 $msg = $context->msg( "tag-$tag-description" );
 175                 if ( !$msg->exists() ) {
 176                         return false;
 177                 }
 178                 if ( $msg->isDisabled() ) {
 179                         // The message exists but is disabled, hide the description.
 180                         return false;
 181                 }
 182
 183                 // Message exists and isn't disabled, use it.
 184                 return $msg;
 185         }
 186
 187         /**
 188          * Get truncated message for the tag's long description.
 189          *
 190          * @param string $tag Tag name.
 191          * @param int $length Maximum length of truncated message, including ellipsis.
 192          * @param IContextSource $context
 193          *
 194          * @return string Truncated long tag description.
 195          */
 196         public static function truncateTagDescription( $tag, $length, IContextSource $context ) {
 197                 $originalDesc = self::tagLongDescriptionMessage( $tag, $context );
 198                 // If there is no tag description, return empty string
 199                 if ( !$originalDesc ) {
 200                         return '';
 201                 }
 202
 203                 $taglessDesc = Sanitizer::stripAllTags( $originalDesc->parse() );
 204
 205                 return $context->getLanguage()->truncateForVisual( $taglessDesc, $length );
 206         }
 207
 208         /**
 209          * Add tags to a change given its rc_id, rev_id and/or log_id
 210          *
 211          * @param string|string[] $tags Tags to add to the change
 212          * @param int|null $rc_id The rc_id of the change to add the tags to
 213          * @param int|null $rev_id The rev_id of the change to add the tags to
 214          * @param int|null $log_id The log_id of the change to add the tags to
 215          * @param string|null $params Params to put in the ct_params field of table 'change_tag'
 216          * @param RecentChange|null $rc Recent change, in case the tagging accompanies the action
 217          * (this should normally be the case)
 218          *
 219          * @throws MWException
 220          * @return bool False if no changes are made, otherwise true
 221          */
 222         public static function addTags( $tags, $rc_id = null, $rev_id = null,
 223                 $log_id = null, $params = null, RecentChange $rc = null
 224         ) {
 225                 $result = self::updateTags( $tags, null, $rc_id, $rev_id, $log_id, $params, $rc );
 226                 return (bool)$result[0];
 227         }
 228
 229         /**
 230          * Add and remove tags to/from a change given its rc_id, rev_id and/or log_id,
 231          * without verifying that the tags exist or are valid. If a tag is present in
 232          * both $tagsToAdd and $tagsToRemove, it will be removed.
 233          *
 234          * This function should only be used by extensions to manipulate tags they
 235          * have registered using the ListDefinedTags hook. When dealing with user
 236          * input, call updateTagsWithChecks() instead.
 237          *
 238          * @param string|array|null $tagsToAdd Tags to add to the change
 239          * @param string|array|null $tagsToRemove Tags to remove from the change
 240          * @param int|null &$rc_id The rc_id of the change to add the tags to.
 241          * Pass a variable whose value is null if the rc_id is not relevant or unknown.
 242          * @param int|null &$rev_id The rev_id of the change to add the tags to.
 243          * Pass a variable whose value is null if the rev_id is not relevant or unknown.
 244          * @param int|null &$log_id The log_id of the change to add the tags to.
 245          * Pass a variable whose value is null if the log_id is not relevant or unknown.
 246          * @param string|null $params Params to put in the ct_params field of table
 247          * 'change_tag' when adding tags
 248          * @param RecentChange|null $rc Recent change being tagged, in case the tagging accompanies
 249          * the action
 250          * @param User|null $user Tagging user, in case the tagging is subsequent to the tagged action
 251          *
 252          * @throws MWException When $rc_id, $rev_id and $log_id are all null
 253          * @return array Index 0 is an array of tags actually added, index 1 is an
 254          * array of tags actually removed, index 2 is an array of tags present on the
 255          * revision or log entry before any changes were made
 256          *
 257          * @since 1.25
 258          */
 259         public static function updateTags( $tagsToAdd, $tagsToRemove, &$rc_id = null,
 260                 &$rev_id = null, &$log_id = null, $params = null, RecentChange $rc = null,
 261                 User $user = null
 262         ) {
 263                 global $wgChangeTagsSchemaMigrationStage;
 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                         if ( $wgChangeTagsSchemaMigrationStage > MIGRATION_OLD ) {
 349                                 foreach ( $tagsToAdd as $tag ) {
 350                                         $changeTagMapping[$tag] = $changeTagDefStore->acquireId( $tag );
 351                                 }
 352
 353                                 $dbw->update(
 354                                         'change_tag_def',
 355                                         [ 'ctd_count = ctd_count + 1' ],
 356                                         [ 'ctd_name' => $tagsToAdd ],
 357                                         __METHOD__
 358                                 );
 359                         }
 360
 361                         $tagsRows = [];
 362                         foreach ( $tagsToAdd as $tag ) {
 363                                 if ( $wgChangeTagsSchemaMigrationStage > MIGRATION_WRITE_BOTH ) {
 364                                         $tagName = null;
 365                                 } else {
 366                                         $tagName = $tag;
 367                                 }
 368                                 // Filter so we don't insert NULLs as zero accidentally.
 369                                 // Keep in mind that $rc_id === null means "I don't care/know about the
 370                                 // rc_id, just delete $tag on this revision/log entry". It doesn't
 371                                 // mean "only delete tags on this revision/log WHERE rc_id IS NULL".
 372                                 $tagsRows[] = array_filter(
 373                                         [
 374                                                 'ct_tag' => $tagName,
 375                                                 'ct_rc_id' => $rc_id,
 376                                                 'ct_log_id' => $log_id,
 377                                                 'ct_rev_id' => $rev_id,
 378                                                 'ct_params' => $params,
 379                                                 'ct_tag_id' => $changeTagMapping[$tag] ?? null,
 380                                         ]
 381                                 );
 382
 383                         }
 384
 385                         $dbw->insert( 'change_tag', $tagsRows, __METHOD__, [ 'IGNORE' ] );
 386                 }
 387
 388                 // delete from change_tag
 389                 if ( count( $tagsToRemove ) ) {
 390                         foreach ( $tagsToRemove as $tag ) {
 391                                 if ( $wgChangeTagsSchemaMigrationStage > MIGRATION_WRITE_BOTH ) {
 392                                         $tagName = null;
 393                                         $tagId = $changeTagDefStore->getId( $tag );
 394                                 } else {
 395                                         $tagName = $tag;
 396                                         $tagId = null;
 397                                 }
 398                                 $conds = array_filter(
 399                                         [
 400                                                 'ct_tag' => $tagName,
 401                                                 'ct_rc_id' => $rc_id,
 402                                                 'ct_log_id' => $log_id,
 403                                                 'ct_rev_id' => $rev_id,
 404                                                 'ct_tag_id' => $tagId,
 405                                         ]
 406                                 );
 407                                 $dbw->delete( 'change_tag', $conds, __METHOD__ );
 408                                 if ( $dbw->affectedRows() && $wgChangeTagsSchemaMigrationStage > MIGRATION_OLD ) {
 409                                         $dbw->update(
 410                                                 'change_tag_def',
 411                                                 [ 'ctd_count = ctd_count - 1' ],
 412                                                 [ 'ctd_name' => $tag ],
 413                                                 __METHOD__
 414                                         );
 415
 416                                         $dbw->delete(
 417                                                 'change_tag_def',
 418                                                 [ 'ctd_name' => $tag, 'ctd_count' => 0, 'ctd_user_defined' => 0 ],
 419                                                 __METHOD__
 420                                         );
 421                                 }
 422                         }
 423                 }
 424
 425                 self::purgeTagUsageCache();
 426
 427                 Hooks::run( 'ChangeTagsAfterUpdateTags', [ $tagsToAdd, $tagsToRemove, $prevTags,
 428                         $rc_id, $rev_id, $log_id, $params, $rc, $user ] );
 429
 430                 return [ $tagsToAdd, $tagsToRemove, $prevTags ];
 431         }
 432
 433         /**
 434          * Adds or removes a given set of tags to/from the relevant row of the
 435          * tag_summary table. Modifies the tagsToAdd and tagsToRemove arrays to
 436          * reflect the tags that were actually added and/or removed.
 437          *
 438          * @param array &$tagsToAdd
 439          * @param array &$tagsToRemove If a tag is present in both $tagsToAdd and
 440          * $tagsToRemove, it will be removed
 441          * @param int|null $rc_id Null if not known or not applicable
 442          * @param int|null $rev_id Null if not known or not applicable
 443          * @param int|null $log_id Null if not known or not applicable
 444          * @param array &$prevTags Optionally outputs a list of the tags that were
 445          * in the tag_summary row to begin with
 446          * @return bool True if any modifications were made, otherwise false
 447          * @since 1.25
 448          */
 449         protected static function updateTagSummaryRow( &$tagsToAdd, &$tagsToRemove,
 450                 $rc_id, $rev_id, $log_id, &$prevTags = []
 451         ) {
 452                 $dbw = wfGetDB( DB_MASTER );
 453
 454                 $tsConds = array_filter( [
 455                         'ts_rc_id' => $rc_id,
 456                         'ts_rev_id' => $rev_id,
 457                         'ts_log_id' => $log_id
 458                 ] );
 459
 460                 // Can't both add and remove a tag at the same time...
 461                 $tagsToAdd = array_diff( $tagsToAdd, $tagsToRemove );
 462
 463                 // Update the summary row.
 464                 // $prevTags can be out of date on replica DBs, especially when addTags is called consecutively,
 465                 // causing loss of tags added recently in tag_summary table.
 466                 $prevTags = $dbw->selectField( 'tag_summary', 'ts_tags', $tsConds, __METHOD__ );
 467                 $prevTags = $prevTags ?: '';
 468                 $prevTags = array_filter( explode( ',', $prevTags ) );
 469
 470                 // add tags
 471                 $tagsToAdd = array_values( array_diff( $tagsToAdd, $prevTags ) );
 472                 $newTags = array_unique( array_merge( $prevTags, $tagsToAdd ) );
 473
 474                 // remove tags
 475                 $tagsToRemove = array_values( array_intersect( $tagsToRemove, $newTags ) );
 476                 $newTags = array_values( array_diff( $newTags, $tagsToRemove ) );
 477
 478                 sort( $prevTags );
 479                 sort( $newTags );
 480                 if ( $prevTags == $newTags ) {
 481                         return false;
 482                 }
 483
 484                 if ( !$newTags ) {
 485                         // No tags left, so delete the row altogether
 486                         $dbw->delete( 'tag_summary', $tsConds, __METHOD__ );
 487                 } else {
 488                         // Specify the non-DEFAULT value columns in the INSERT/REPLACE clause
 489                         $row = array_filter( [ 'ts_tags' => implode( ',', $newTags ) ] + $tsConds );
 490                         // Check the unique keys for conflicts, ignoring any NULL *_id values
 491                         $uniqueKeys = [];
 492                         foreach ( [ 'ts_rev_id', 'ts_rc_id', 'ts_log_id' ] as $uniqueColumn ) {
 493                                 if ( isset( $row[$uniqueColumn] ) ) {
 494                                         $uniqueKeys[] = [ $uniqueColumn ];
 495                                 }
 496                         }
 497
 498                         $dbw->replace( 'tag_summary', $uniqueKeys, $row, __METHOD__ );
 499                 }
 500
 501                 return true;
 502         }
 503
 504         /**
 505          * Helper function to generate a fatal status with a 'not-allowed' type error.
 506          *
 507          * @param string $msgOne Message key to use in the case of one tag
 508          * @param string $msgMulti Message key to use in the case of more than one tag
 509          * @param array $tags Restricted tags (passed as $1 into the message, count of
 510          * $tags passed as $2)
 511          * @return Status
 512          * @since 1.25
 513          */
 514         protected static function restrictedTagError( $msgOne, $msgMulti, $tags ) {
 515                 $lang = RequestContext::getMain()->getLanguage();
 516                 $count = count( $tags );
 517                 return Status::newFatal( ( $count > 1 ) ? $msgMulti : $msgOne,
 518                         $lang->commaList( $tags ), $count );
 519         }
 520
 521         /**
 522          * Is it OK to allow the user to apply all the specified tags at the same time
 523          * as they edit/make the change?
 524          *
 525          * Extensions should not use this function, unless directly handling a user
 526          * request to add a tag to a revision or log entry that the user is making.
 527          *
 528          * @param array $tags Tags that you are interested in applying
 529          * @param User|null $user User whose permission you wish to check, or null to
 530          * check for a generic non-blocked user with the relevant rights
 531          * @return Status
 532          * @since 1.25
 533          */
 534         public static function canAddTagsAccompanyingChange( array $tags, User $user = null ) {
 535                 if ( !is_null( $user ) ) {
 536                         if ( !$user->isAllowed( 'applychangetags' ) ) {
 537                                 return Status::newFatal( 'tags-apply-no-permission' );
 538                         } elseif ( $user->isBlocked() ) {
 539                                 return Status::newFatal( 'tags-apply-blocked', $user->getName() );
 540                         }
 541                 }
 542
 543                 // to be applied, a tag has to be explicitly defined
 544                 $allowedTags = self::listExplicitlyDefinedTags();
 545                 Hooks::run( 'ChangeTagsAllowedAdd', [ &$allowedTags, $tags, $user ] );
 546                 $disallowedTags = array_diff( $tags, $allowedTags );
 547                 if ( $disallowedTags ) {
 548                         return self::restrictedTagError( 'tags-apply-not-allowed-one',
 549                                 'tags-apply-not-allowed-multi', $disallowedTags );
 550                 }
 551
 552                 return Status::newGood();
 553         }
 554
 555         /**
 556          * Adds tags to a given change, checking whether it is allowed first, but
 557          * without adding a log entry. Useful for cases where the tag is being added
 558          * along with the action that generated the change (e.g. tagging an edit as
 559          * it is being made).
 560          *
 561          * Extensions should not use this function, unless directly handling a user
 562          * request to add a particular tag. Normally, extensions should call
 563          * ChangeTags::updateTags() instead.
 564          *
 565          * @param array $tags Tags to apply
 566          * @param int|null $rc_id The rc_id of the change to add the tags to
 567          * @param int|null $rev_id The rev_id of the change to add the tags to
 568          * @param int|null $log_id The log_id of the change to add the tags to
 569          * @param string $params Params to put in the ct_params field of table
 570          * 'change_tag' when adding tags
 571          * @param User $user Who to give credit for the action
 572          * @return Status
 573          * @since 1.25
 574          */
 575         public static function addTagsAccompanyingChangeWithChecks(
 576                 array $tags, $rc_id, $rev_id, $log_id, $params, User $user
 577         ) {
 578                 // are we allowed to do this?
 579                 $result = self::canAddTagsAccompanyingChange( $tags, $user );
 580                 if ( !$result->isOK() ) {
 581                         $result->value = null;
 582                         return $result;
 583                 }
 584
 585                 // do it!
 586                 self::addTags( $tags, $rc_id, $rev_id, $log_id, $params );
 587
 588                 return Status::newGood( true );
 589         }
 590
 591         /**
 592          * Is it OK to allow the user to adds and remove the given tags tags to/from a
 593          * change?
 594          *
 595          * Extensions should not use this function, unless directly handling a user
 596          * request to add or remove tags from an existing revision or log entry.
 597          *
 598          * @param array $tagsToAdd Tags that you are interested in adding
 599          * @param array $tagsToRemove Tags that you are interested in removing
 600          * @param User|null $user User whose permission you wish to check, or null to
 601          * check for a generic non-blocked user with the relevant rights
 602          * @return Status
 603          * @since 1.25
 604          */
 605         public static function canUpdateTags( array $tagsToAdd, array $tagsToRemove,
 606                 User $user = null
 607         ) {
 608                 if ( !is_null( $user ) ) {
 609                         if ( !$user->isAllowed( 'changetags' ) ) {
 610                                 return Status::newFatal( 'tags-update-no-permission' );
 611                         } elseif ( $user->isBlocked() ) {
 612                                 return Status::newFatal( 'tags-update-blocked', $user->getName() );
 613                         }
 614                 }
 615
 616                 if ( $tagsToAdd ) {
 617                         // to be added, a tag has to be explicitly defined
 618                         // @todo Allow extensions to define tags that can be applied by users...
 619                         $explicitlyDefinedTags = self::listExplicitlyDefinedTags();
 620                         $diff = array_diff( $tagsToAdd, $explicitlyDefinedTags );
 621                         if ( $diff ) {
 622                                 return self::restrictedTagError( 'tags-update-add-not-allowed-one',
 623                                         'tags-update-add-not-allowed-multi', $diff );
 624                         }
 625                 }
 626
 627                 if ( $tagsToRemove ) {
 628                         // to be removed, a tag must not be defined by an extension, or equivalently it
 629                         // has to be either explicitly defined or not defined at all
 630                         // (assuming no edge case of a tag both explicitly-defined and extension-defined)
 631                         $softwareDefinedTags = self::listSoftwareDefinedTags();
 632                         $intersect = array_intersect( $tagsToRemove, $softwareDefinedTags );
 633                         if ( $intersect ) {
 634                                 return self::restrictedTagError( 'tags-update-remove-not-allowed-one',
 635                                         'tags-update-remove-not-allowed-multi', $intersect );
 636                         }
 637                 }
 638
 639                 return Status::newGood();
 640         }
 641
 642         /**
 643          * Adds and/or removes tags to/from a given change, checking whether it is
 644          * allowed first, and adding a log entry afterwards.
 645          *
 646          * Includes a call to ChangeTags::canUpdateTags(), so your code doesn't need
 647          * to do that. However, it doesn't check whether the *_id parameters are a
 648          * valid combination. That is up to you to enforce. See ApiTag::execute() for
 649          * an example.
 650          *
 651          * Extensions should generally avoid this function. Call
 652          * ChangeTags::updateTags() instead, unless directly handling a user request
 653          * to add or remove tags from an existing revision or log entry.
 654          *
 655          * @param array|null $tagsToAdd If none, pass array() or null
 656          * @param array|null $tagsToRemove If none, pass array() or null
 657          * @param int|null $rc_id The rc_id of the change to add the tags to
 658          * @param int|null $rev_id The rev_id of the change to add the tags to
 659          * @param int|null $log_id The log_id of the change to add the tags to
 660          * @param string $params Params to put in the ct_params field of table
 661          * 'change_tag' when adding tags
 662          * @param string $reason Comment for the log
 663          * @param User $user Who to give credit for the action
 664          * @return Status If successful, the value of this Status object will be an
 665          * object (stdClass) with the following fields:
 666          *  - logId: the ID of the added log entry, or null if no log entry was added
 667          *    (i.e. no operation was performed)
 668          *  - addedTags: an array containing the tags that were actually added
 669          *  - removedTags: an array containing the tags that were actually removed
 670          * @since 1.25
 671          */
 672         public static function updateTagsWithChecks( $tagsToAdd, $tagsToRemove,
 673                 $rc_id, $rev_id, $log_id, $params, $reason, User $user
 674         ) {
 675                 if ( is_null( $tagsToAdd ) ) {
 676                         $tagsToAdd = [];
 677                 }
 678                 if ( is_null( $tagsToRemove ) ) {
 679                         $tagsToRemove = [];
 680                 }
 681                 if ( !$tagsToAdd && !$tagsToRemove ) {
 682                         // no-op, don't bother
 683                         return Status::newGood( (object)[
 684                                 'logId' => null,
 685                                 'addedTags' => [],
 686                                 'removedTags' => [],
 687                         ] );
 688                 }
 689
 690                 // are we allowed to do this?
 691                 $result = self::canUpdateTags( $tagsToAdd, $tagsToRemove, $user );
 692                 if ( !$result->isOK() ) {
 693                         $result->value = null;
 694                         return $result;
 695                 }
 696
 697                 // basic rate limiting
 698                 if ( $user->pingLimiter( 'changetag' ) ) {
 699                         return Status::newFatal( 'actionthrottledtext' );
 700                 }
 701
 702                 // do it!
 703                 list( $tagsAdded, $tagsRemoved, $initialTags ) = self::updateTags( $tagsToAdd,
 704                         $tagsToRemove, $rc_id, $rev_id, $log_id, $params, null, $user );
 705                 if ( !$tagsAdded && !$tagsRemoved ) {
 706                         // no-op, don't log it
 707                         return Status::newGood( (object)[
 708                                 'logId' => null,
 709                                 'addedTags' => [],
 710                                 'removedTags' => [],
 711                         ] );
 712                 }
 713
 714                 // log it
 715                 $logEntry = new ManualLogEntry( 'tag', 'update' );
 716                 $logEntry->setPerformer( $user );
 717                 $logEntry->setComment( $reason );
 718
 719                 // find the appropriate target page
 720                 if ( $rev_id ) {
 721                         $rev = Revision::newFromId( $rev_id );
 722                         if ( $rev ) {
 723                                 $logEntry->setTarget( $rev->getTitle() );
 724                         }
 725                 } elseif ( $log_id ) {
 726                         // This function is from revision deletion logic and has nothing to do with
 727                         // change tags, but it appears to be the only other place in core where we
 728                         // perform logged actions on log items.
 729                         $logEntry->setTarget( RevDelLogList::suggestTarget( null, [ $log_id ] ) );
 730                 }
 731
 732                 if ( !$logEntry->getTarget() ) {
 733                         // target is required, so we have to set something
 734                         $logEntry->setTarget( SpecialPage::getTitleFor( 'Tags' ) );
 735                 }
 736
 737                 $logParams = [
 738                         '4::revid' => $rev_id,
 739                         '5::logid' => $log_id,
 740                         '6:list:tagsAdded' => $tagsAdded,
 741                         '7:number:tagsAddedCount' => count( $tagsAdded ),
 742                         '8:list:tagsRemoved' => $tagsRemoved,
 743                         '9:number:tagsRemovedCount' => count( $tagsRemoved ),
 744                         'initialTags' => $initialTags,
 745                 ];
 746                 $logEntry->setParameters( $logParams );
 747                 $logEntry->setRelations( [ 'Tag' => array_merge( $tagsAdded, $tagsRemoved ) ] );
 748
 749                 $dbw = wfGetDB( DB_MASTER );
 750                 $logId = $logEntry->insert( $dbw );
 751                 // Only send this to UDP, not RC, similar to patrol events
 752                 $logEntry->publish( $logId, 'udp' );
 753
 754                 return Status::newGood( (object)[
 755                         'logId' => $logId,
 756                         'addedTags' => $tagsAdded,
 757                         'removedTags' => $tagsRemoved,
 758                 ] );
 759         }
 760
 761         /**
 762          * Applies all tags-related changes to a query.
 763          * Handles selecting tags, and filtering.
 764          * Needs $tables to be set up properly, so we can figure out which join conditions to use.
 765          *
 766          * WARNING: If $filter_tag contains more than one tag, this function will add DISTINCT,
 767          * which may cause performance problems for your query unless you put the ID field of your
 768          * table at the end of the ORDER BY, and set a GROUP BY equal to the ORDER BY. For example,
 769          * if you had ORDER BY foo_timestamp DESC, you will now need GROUP BY foo_timestamp, foo_id
 770          * ORDER BY foo_timestamp DESC, foo_id DESC.
 771          *
 772          * @param string|array &$tables Table names, see Database::select
 773          * @param string|array &$fields Fields used in query, see Database::select
 774          * @param string|array &$conds Conditions used in query, see Database::select
 775          * @param array &$join_conds Join conditions, see Database::select
 776          * @param string|array &$options Options, see Database::select
 777          * @param string|array $filter_tag Tag(s) to select on
 778          *
 779          * @throws MWException When unable to determine appropriate JOIN condition for tagging
 780          */
 781         public static function modifyDisplayQuery( &$tables, &$fields, &$conds,
 782                 &$join_conds, &$options, $filter_tag = ''
 783         ) {
 784                 global $wgUseTagFilter, $wgChangeTagsSchemaMigrationStage;
 785
 786                 // Normalize to arrays
 787                 $tables = (array)$tables;
 788                 $fields = (array)$fields;
 789                 $conds = (array)$conds;
 790                 $options = (array)$options;
 791
 792                 // Figure out which ID field to use
 793                 if ( in_array( 'recentchanges', $tables ) ) {
 794                         $join_cond = 'ct_rc_id=rc_id';
 795                 } elseif ( in_array( 'logging', $tables ) ) {
 796                         $join_cond = 'ct_log_id=log_id';
 797                 } elseif ( in_array( 'revision', $tables ) ) {
 798                         $join_cond = 'ct_rev_id=rev_id';
 799                 } elseif ( in_array( 'archive', $tables ) ) {
 800                         $join_cond = 'ct_rev_id=ar_rev_id';
 801                 } else {
 802                         throw new MWException( 'Unable to determine appropriate JOIN condition for tagging.' );
 803                 }
 804
 805                 if ( $wgChangeTagsSchemaMigrationStage > MIGRATION_WRITE_BOTH ) {
 806                         $tables[] = 'change_tag_def';
 807                         $join_cond = [ $join_cond, 'ct_tag_id=ctd_id' ];
 808                         $field = 'ctd_name';
 809                 } else {
 810                         $field = 'ct_tag';
 811                 }
 812
 813                 $fields['ts_tags'] = wfGetDB( DB_REPLICA )->buildGroupConcatField(
 814                         ',', 'change_tag', $field, $join_cond
 815                 );
 816
 817                 if ( $wgUseTagFilter && $filter_tag ) {
 818                         // Somebody wants to filter on a tag.
 819                         // Add an INNER JOIN on change_tag
 820
 821                         $tables[] = 'change_tag';
 822                         $join_conds['change_tag'] = [ 'INNER JOIN', $join_cond ];
 823                         if ( $wgChangeTagsSchemaMigrationStage > MIGRATION_WRITE_BOTH ) {
 824                                 $tables[] = 'change_tag_def';
 825                                 $join_conds['change_tag_def'] = [ 'INNER JOIN', 'ct_tag_id=ctd_id' ];
 826                                 $conds['ctd_name'] = $filter_tag;
 827                         } else {
 828                                 $conds['ct_tag'] = $filter_tag;
 829                         }
 830
 831                         if (
 832                                 is_array( $filter_tag ) && count( $filter_tag ) > 1 &&
 833                                 !in_array( 'DISTINCT', $options )
 834                         ) {
 835                                 $options[] = 'DISTINCT';
 836                         }
 837                 }
 838         }
 839
 840         /**
 841          * Build a text box to select a change tag
 842          *
 843          * @param string $selected Tag to select by default
 844          * @param bool $ooui Use an OOUI TextInputWidget as selector instead of a non-OOUI input field
 845          *        You need to call OutputPage::enableOOUI() yourself.
 846          * @param IContextSource|null $context
 847          * @note Even though it takes null as a valid argument, an IContextSource is preferred
 848          *       in a new code, as the null value can change in the future
 849          * @return array an array of (label, selector)
 850          */
 851         public static function buildTagFilterSelector(
 852                 $selected = '', $ooui = false, IContextSource $context = null
 853         ) {
 854                 if ( !$context ) {
 855                         $context = RequestContext::getMain();
 856                 }
 857
 858                 $config = $context->getConfig();
 859                 if ( !$config->get( 'UseTagFilter' ) || !count( self::listDefinedTags() ) ) {
 860                         return [];
 861                 }
 862
 863                 $data = [
 864                         Html::rawElement(
 865                                 'label',
 866                                 [ 'for' => 'tagfilter' ],
 867                                 $context->msg( 'tag-filter' )->parse()
 868                         )
 869                 ];
 870
 871                 if ( $ooui ) {
 872                         $data[] = new OOUI\TextInputWidget( [
 873                                 'id' => 'tagfilter',
 874                                 'name' => 'tagfilter',
 875                                 'value' => $selected,
 876                                 'classes' => 'mw-tagfilter-input',
 877                         ] );
 878                 } else {
 879                         $data[] = Xml::input(
 880                                 'tagfilter',
 881                                 20,
 882                                 $selected,
 883                                 [ 'class' => 'mw-tagfilter-input mw-ui-input mw-ui-input-inline', 'id' => 'tagfilter' ]
 884                         );
 885                 }
 886
 887                 return $data;
 888         }
 889
 890         /**
 891          * Defines a tag in the valid_tag table and/or update ctd_user_defined field in change_tag_def,
 892          * without checking that the tag name is valid.
 893          * Extensions should NOT use this function; they can use the ListDefinedTags
 894          * hook instead.
 895          *
 896          * @param string $tag Tag to create
 897          * @since 1.25
 898          */
 899         public static function defineTag( $tag ) {
 900                 global $wgChangeTagsSchemaMigrationStage;
 901
 902                 $dbw = wfGetDB( DB_MASTER );
 903                 if ( $wgChangeTagsSchemaMigrationStage > MIGRATION_OLD ) {
 904                         $tagDef = [
 905                                 'ctd_name' => $tag,
 906                                 'ctd_user_defined' => 1,
 907                                 'ctd_count' => 0
 908                         ];
 909                         $dbw->upsert(
 910                                 'change_tag_def',
 911                                 $tagDef,
 912                                 [ 'ctd_name' ],
 913                                 [ 'ctd_user_defined' => 1 ],
 914                                 __METHOD__
 915                         );
 916                 }
 917
 918                 $dbw->replace(
 919                         'valid_tag',
 920                         [ 'vt_tag' ],
 921                         [ 'vt_tag' => $tag ],
 922                         __METHOD__
 923                 );
 924
 925                 // clear the memcache of defined tags
 926                 self::purgeTagCacheAll();
 927         }
 928
 929         /**
 930          * Removes a tag from the valid_tag table and/or update ctd_user_defined field in change_tag_def.
 931          * The tag may remain in use by extensions, and may still show up as 'defined'
 932          * if an extension is setting it from the ListDefinedTags hook.
 933          *
 934          * @param string $tag Tag to remove
 935          * @since 1.25
 936          */
 937         public static function undefineTag( $tag ) {
 938                 global $wgChangeTagsSchemaMigrationStage;
 939
 940                 $dbw = wfGetDB( DB_MASTER );
 941
 942                 if ( $wgChangeTagsSchemaMigrationStage > MIGRATION_OLD ) {
 943                         $dbw->update(
 944                                 'change_tag_def',
 945                                 [ 'ctd_user_defined' => 0 ],
 946                                 [ 'ctd_name' => $tag ],
 947                                 __METHOD__
 948                         );
 949
 950                         $dbw->delete(
 951                                 'change_tag_def',
 952                                 [ 'ctd_name' => $tag, 'ctd_count' => 0 ],
 953                                 __METHOD__
 954                         );
 955                 }
 956
 957                 $dbw->delete( 'valid_tag', [ 'vt_tag' => $tag ], __METHOD__ );
 958
 959                 // clear the memcache of defined tags
 960                 self::purgeTagCacheAll();
 961         }
 962
 963         /**
 964          * Writes a tag action into the tag management log.
 965          *
 966          * @param string $action
 967          * @param string $tag
 968          * @param string $reason
 969          * @param User $user Who to attribute the action to
 970          * @param int|null $tagCount For deletion only, how many usages the tag had before
 971          * it was deleted.
 972          * @param array $logEntryTags Change tags to apply to the entry
 973          * that will be created in the tag management log
 974          * @return int ID of the inserted log entry
 975          * @since 1.25
 976          */
 977         protected static function logTagManagementAction( $action, $tag, $reason,
 978                 User $user, $tagCount = null, array $logEntryTags = []
 979         ) {
 980                 $dbw = wfGetDB( DB_MASTER );
 981
 982                 $logEntry = new ManualLogEntry( 'managetags', $action );
 983                 $logEntry->setPerformer( $user );
 984                 // target page is not relevant, but it has to be set, so we just put in
 985                 // the title of Special:Tags
 986                 $logEntry->setTarget( Title::newFromText( 'Special:Tags' ) );
 987                 $logEntry->setComment( $reason );
 988
 989                 $params = [ '4::tag' => $tag ];
 990                 if ( !is_null( $tagCount ) ) {
 991                         $params['5:number:count'] = $tagCount;
 992                 }
 993                 $logEntry->setParameters( $params );
 994                 $logEntry->setRelations( [ 'Tag' => $tag ] );
 995                 $logEntry->setTags( $logEntryTags );
 996
 997                 $logId = $logEntry->insert( $dbw );
 998                 $logEntry->publish( $logId );
 999                 return $logId;
1000         }
1001
1002         /**
1003          * Is it OK to allow the user to activate this tag?
1004          *
1005          * @param string $tag Tag that you are interested in activating
1006          * @param User|null $user User whose permission you wish to check, or null if
1007          * you don't care (e.g. maintenance scripts)
1008          * @return Status
1009          * @since 1.25
1010          */
1011         public static function canActivateTag( $tag, User $user = null ) {
1012                 if ( !is_null( $user ) ) {
1013                         if ( !$user->isAllowed( 'managechangetags' ) ) {
1014                                 return Status::newFatal( 'tags-manage-no-permission' );
1015                         } elseif ( $user->isBlocked() ) {
1016                                 return Status::newFatal( 'tags-manage-blocked', $user->getName() );
1017                         }
1018                 }
1019
1020                 // defined tags cannot be activated (a defined tag is either extension-
1021                 // defined, in which case the extension chooses whether or not to active it;
1022                 // or user-defined, in which case it is considered active)
1023                 $definedTags = self::listDefinedTags();
1024                 if ( in_array( $tag, $definedTags ) ) {
1025                         return Status::newFatal( 'tags-activate-not-allowed', $tag );
1026                 }
1027
1028                 // non-existing tags cannot be activated
1029                 $tagUsage = self::tagUsageStatistics();
1030                 if ( !isset( $tagUsage[$tag] ) ) { // we already know the tag is undefined
1031                         return Status::newFatal( 'tags-activate-not-found', $tag );
1032                 }
1033
1034                 return Status::newGood();
1035         }
1036
1037         /**
1038          * Activates a tag, checking whether it is allowed first, and adding a log
1039          * entry afterwards.
1040          *
1041          * Includes a call to ChangeTag::canActivateTag(), so your code doesn't need
1042          * to do that.
1043          *
1044          * @param string $tag
1045          * @param string $reason
1046          * @param User $user Who to give credit for the action
1047          * @param bool $ignoreWarnings Can be used for API interaction, default false
1048          * @param array $logEntryTags Change tags to apply to the entry
1049          * that will be created in the tag management log
1050          * @return Status If successful, the Status contains the ID of the added log
1051          * entry as its value
1052          * @since 1.25
1053          */
1054         public static function activateTagWithChecks( $tag, $reason, User $user,
1055                 $ignoreWarnings = false, array $logEntryTags = []
1056         ) {
1057                 // are we allowed to do this?
1058                 $result = self::canActivateTag( $tag, $user );
1059                 if ( $ignoreWarnings ? !$result->isOK() : !$result->isGood() ) {
1060                         $result->value = null;
1061                         return $result;
1062                 }
1063
1064                 // do it!
1065                 self::defineTag( $tag );
1066
1067                 // log it
1068                 $logId = self::logTagManagementAction( 'activate', $tag, $reason, $user,
1069                         null, $logEntryTags );
1070
1071                 return Status::newGood( $logId );
1072         }
1073
1074         /**
1075          * Is it OK to allow the user to deactivate this tag?
1076          *
1077          * @param string $tag Tag that you are interested in deactivating
1078          * @param User|null $user User whose permission you wish to check, or null if
1079          * you don't care (e.g. maintenance scripts)
1080          * @return Status
1081          * @since 1.25
1082          */
1083         public static function canDeactivateTag( $tag, User $user = null ) {
1084                 if ( !is_null( $user ) ) {
1085                         if ( !$user->isAllowed( 'managechangetags' ) ) {
1086                                 return Status::newFatal( 'tags-manage-no-permission' );
1087                         } elseif ( $user->isBlocked() ) {
1088                                 return Status::newFatal( 'tags-manage-blocked', $user->getName() );
1089                         }
1090                 }
1091
1092                 // only explicitly-defined tags can be deactivated
1093                 $explicitlyDefinedTags = self::listExplicitlyDefinedTags();
1094                 if ( !in_array( $tag, $explicitlyDefinedTags ) ) {
1095                         return Status::newFatal( 'tags-deactivate-not-allowed', $tag );
1096                 }
1097                 return Status::newGood();
1098         }
1099
1100         /**
1101          * Deactivates a tag, checking whether it is allowed first, and adding a log
1102          * entry afterwards.
1103          *
1104          * Includes a call to ChangeTag::canDeactivateTag(), so your code doesn't need
1105          * to do that.
1106          *
1107          * @param string $tag
1108          * @param string $reason
1109          * @param User $user Who to give credit for the action
1110          * @param bool $ignoreWarnings Can be used for API interaction, default false
1111          * @param array $logEntryTags Change tags to apply to the entry
1112          * that will be created in the tag management log
1113          * @return Status If successful, the Status contains the ID of the added log
1114          * entry as its value
1115          * @since 1.25
1116          */
1117         public static function deactivateTagWithChecks( $tag, $reason, User $user,
1118                 $ignoreWarnings = false, array $logEntryTags = []
1119         ) {
1120                 // are we allowed to do this?
1121                 $result = self::canDeactivateTag( $tag, $user );
1122                 if ( $ignoreWarnings ? !$result->isOK() : !$result->isGood() ) {
1123                         $result->value = null;
1124                         return $result;
1125                 }
1126
1127                 // do it!
1128                 self::undefineTag( $tag );
1129
1130                 // log it
1131                 $logId = self::logTagManagementAction( 'deactivate', $tag, $reason, $user,
1132                         null, $logEntryTags );
1133
1134                 return Status::newGood( $logId );
1135         }
1136
1137         /**
1138          * Is the tag name valid?
1139          *
1140          * @param string $tag Tag that you are interested in creating
1141          * @return Status
1142          * @since 1.30
1143          */
1144         public static function isTagNameValid( $tag ) {
1145                 // no empty tags
1146                 if ( $tag === '' ) {
1147                         return Status::newFatal( 'tags-create-no-name' );
1148                 }
1149
1150                 // tags cannot contain commas (used as a delimiter in tag_summary table),
1151                 // pipe (used as a delimiter between multiple tags in
1152                 // SpecialRecentchanges and friends), or slashes (would break tag description messages in
1153                 // MediaWiki namespace)
1154                 if ( strpos( $tag, ',' ) !== false || strpos( $tag, '|' ) !== false
1155                         || strpos( $tag, '/' ) !== false ) {
1156                         return Status::newFatal( 'tags-create-invalid-chars' );
1157                 }
1158
1159                 // could the MediaWiki namespace description messages be created?
1160                 $title = Title::makeTitleSafe( NS_MEDIAWIKI, "Tag-$tag-description" );
1161                 if ( is_null( $title ) ) {
1162                         return Status::newFatal( 'tags-create-invalid-title-chars' );
1163                 }
1164
1165                 return Status::newGood();
1166         }
1167
1168         /**
1169          * Is it OK to allow the user to create this tag?
1170          *
1171          * Extensions should NOT use this function. In most cases, a tag can be
1172          * defined using the ListDefinedTags hook without any checking.
1173          *
1174          * @param string $tag Tag that you are interested in creating
1175          * @param User|null $user User whose permission you wish to check, or null if
1176          * you don't care (e.g. maintenance scripts)
1177          * @return Status
1178          * @since 1.25
1179          */
1180         public static function canCreateTag( $tag, User $user = null ) {
1181                 if ( !is_null( $user ) ) {
1182                         if ( !$user->isAllowed( 'managechangetags' ) ) {
1183                                 return Status::newFatal( 'tags-manage-no-permission' );
1184                         } elseif ( $user->isBlocked() ) {
1185                                 return Status::newFatal( 'tags-manage-blocked', $user->getName() );
1186                         }
1187                 }
1188
1189                 $status = self::isTagNameValid( $tag );
1190                 if ( !$status->isGood() ) {
1191                         return $status;
1192                 }
1193
1194                 // does the tag already exist?
1195                 $tagUsage = self::tagUsageStatistics();
1196                 if ( isset( $tagUsage[$tag] ) || in_array( $tag, self::listDefinedTags() ) ) {
1197                         return Status::newFatal( 'tags-create-already-exists', $tag );
1198                 }
1199
1200                 // check with hooks
1201                 $canCreateResult = Status::newGood();
1202                 Hooks::run( 'ChangeTagCanCreate', [ $tag, $user, &$canCreateResult ] );
1203                 return $canCreateResult;
1204         }
1205
1206         /**
1207          * Creates a tag by adding a row to the `valid_tag` table.
1208          * and/or add it to `change_tag_def` table.
1209          *
1210          * Extensions should NOT use this function; they can use the ListDefinedTags
1211          * hook instead.
1212          *
1213          * Includes a call to ChangeTag::canCreateTag(), so your code doesn't need to
1214          * do that.
1215          *
1216          * @param string $tag
1217          * @param string $reason
1218          * @param User $user Who to give credit for the action
1219          * @param bool $ignoreWarnings Can be used for API interaction, default false
1220          * @param array $logEntryTags Change tags to apply to the entry
1221          * that will be created in the tag management log
1222          * @return Status If successful, the Status contains the ID of the added log
1223          * entry as its value
1224          * @since 1.25
1225          */
1226         public static function createTagWithChecks( $tag, $reason, User $user,
1227                 $ignoreWarnings = false, array $logEntryTags = []
1228         ) {
1229                 // are we allowed to do this?
1230                 $result = self::canCreateTag( $tag, $user );
1231                 if ( $ignoreWarnings ? !$result->isOK() : !$result->isGood() ) {
1232                         $result->value = null;
1233                         return $result;
1234                 }
1235
1236                 // do it!
1237                 self::defineTag( $tag );
1238
1239                 // log it
1240                 $logId = self::logTagManagementAction( 'create', $tag, $reason, $user,
1241                         null, $logEntryTags );
1242
1243                 return Status::newGood( $logId );
1244         }
1245
1246         /**
1247          * Permanently removes all traces of a tag from the DB. Good for removing
1248          * misspelt or temporary tags.
1249          *
1250          * This function should be directly called by maintenance scripts only, never
1251          * by user-facing code. See deleteTagWithChecks() for functionality that can
1252          * safely be exposed to users.
1253          *
1254          * @param string $tag Tag to remove
1255          * @return Status The returned status will be good unless a hook changed it
1256          * @since 1.25
1257          */
1258         public static function deleteTagEverywhere( $tag ) {
1259                 global $wgChangeTagsSchemaMigrationStage;
1260                 $dbw = wfGetDB( DB_MASTER );
1261                 $dbw->startAtomic( __METHOD__ );
1262
1263                 // delete from valid_tag and/or set ctd_user_defined = 0
1264                 self::undefineTag( $tag );
1265
1266                 if ( $wgChangeTagsSchemaMigrationStage > MIGRATION_WRITE_BOTH ) {
1267                         $tagId = MediaWikiServices::getInstance()->getChangeTagDefStore()->getId( $tag );
1268                         $conditions = [ 'ct_tag_id' => $tagId ];
1269                 } else {
1270                         $conditions = [ 'ct_tag' => $tag ];
1271                 }
1272
1273                 // find out which revisions use this tag, so we can delete from tag_summary
1274                 $result = $dbw->select( 'change_tag',
1275                         [ 'ct_rc_id', 'ct_log_id', 'ct_rev_id' ],
1276                         $conditions,
1277                         __METHOD__ );
1278                 foreach ( $result as $row ) {
1279                         // remove the tag from the relevant row of tag_summary
1280                         $tagsToAdd = [];
1281                         $tagsToRemove = [ $tag ];
1282                         self::updateTagSummaryRow( $tagsToAdd, $tagsToRemove, $row->ct_rc_id,
1283                                 $row->ct_rev_id, $row->ct_log_id );
1284                 }
1285
1286                 // delete from change_tag
1287                 if ( $wgChangeTagsSchemaMigrationStage > MIGRATION_WRITE_BOTH ) {
1288                         $tagId = MediaWikiServices::getInstance()->getChangeTagDefStore()->getId( $tag );
1289                         $dbw->delete( 'change_tag', [ 'ct_tag_id' => $tagId ], __METHOD__ );
1290                 } else {
1291                         $dbw->delete( 'change_tag', [ 'ct_tag' => $tag ], __METHOD__ );
1292                 }
1293
1294                 if ( $wgChangeTagsSchemaMigrationStage > MIGRATION_OLD ) {
1295                         $dbw->delete( 'change_tag_def', [ 'ctd_name' => $tag ], __METHOD__ );
1296                 }
1297
1298                 $dbw->endAtomic( __METHOD__ );
1299
1300                 // give extensions a chance
1301                 $status = Status::newGood();
1302                 Hooks::run( 'ChangeTagAfterDelete', [ $tag, &$status ] );
1303                 // let's not allow error results, as the actual tag deletion succeeded
1304                 if ( !$status->isOK() ) {
1305                         wfDebug( 'ChangeTagAfterDelete error condition downgraded to warning' );
1306                         $status->setOK( true );
1307                 }
1308
1309                 // clear the memcache of defined tags
1310                 self::purgeTagCacheAll();
1311
1312                 return $status;
1313         }
1314
1315         /**
1316          * Is it OK to allow the user to delete this tag?
1317          *
1318          * @param string $tag Tag that you are interested in deleting
1319          * @param User|null $user User whose permission you wish to check, or null if
1320          * you don't care (e.g. maintenance scripts)
1321          * @return Status
1322          * @since 1.25
1323          */
1324         public static function canDeleteTag( $tag, User $user = null ) {
1325                 $tagUsage = self::tagUsageStatistics();
1326
1327                 if ( !is_null( $user ) ) {
1328                         if ( !$user->isAllowed( 'deletechangetags' ) ) {
1329                                 return Status::newFatal( 'tags-delete-no-permission' );
1330                         } elseif ( $user->isBlocked() ) {
1331                                 return Status::newFatal( 'tags-manage-blocked', $user->getName() );
1332                         }
1333                 }
1334
1335                 if ( !isset( $tagUsage[$tag] ) && !in_array( $tag, self::listDefinedTags() ) ) {
1336                         return Status::newFatal( 'tags-delete-not-found', $tag );
1337                 }
1338
1339                 if ( isset( $tagUsage[$tag] ) && $tagUsage[$tag] > self::MAX_DELETE_USES ) {
1340                         return Status::newFatal( 'tags-delete-too-many-uses', $tag, self::MAX_DELETE_USES );
1341                 }
1342
1343                 $softwareDefined = self::listSoftwareDefinedTags();
1344                 if ( in_array( $tag, $softwareDefined ) ) {
1345                         // extension-defined tags can't be deleted unless the extension
1346                         // specifically allows it
1347                         $status = Status::newFatal( 'tags-delete-not-allowed' );
1348                 } else {
1349                         // user-defined tags are deletable unless otherwise specified
1350                         $status = Status::newGood();
1351                 }
1352
1353                 Hooks::run( 'ChangeTagCanDelete', [ $tag, $user, &$status ] );
1354                 return $status;
1355         }
1356
1357         /**
1358          * Deletes a tag, checking whether it is allowed first, and adding a log entry
1359          * afterwards.
1360          *
1361          * Includes a call to ChangeTag::canDeleteTag(), so your code doesn't need to
1362          * do that.
1363          *
1364          * @param string $tag
1365          * @param string $reason
1366          * @param User $user Who to give credit for the action
1367          * @param bool $ignoreWarnings Can be used for API interaction, default false
1368          * @param array $logEntryTags Change tags to apply to the entry
1369          * that will be created in the tag management log
1370          * @return Status If successful, the Status contains the ID of the added log
1371          * entry as its value
1372          * @since 1.25
1373          */
1374         public static function deleteTagWithChecks( $tag, $reason, User $user,
1375                 $ignoreWarnings = false, array $logEntryTags = []
1376         ) {
1377                 // are we allowed to do this?
1378                 $result = self::canDeleteTag( $tag, $user );
1379                 if ( $ignoreWarnings ? !$result->isOK() : !$result->isGood() ) {
1380                         $result->value = null;
1381                         return $result;
1382                 }
1383
1384                 // store the tag usage statistics
1385                 $tagUsage = self::tagUsageStatistics();
1386                 $hitcount = $tagUsage[$tag] ?? 0;
1387
1388                 // do it!
1389                 $deleteResult = self::deleteTagEverywhere( $tag );
1390                 if ( !$deleteResult->isOK() ) {
1391                         return $deleteResult;
1392                 }
1393
1394                 // log it
1395                 $logId = self::logTagManagementAction( 'delete', $tag, $reason, $user,
1396                         $hitcount, $logEntryTags );
1397
1398                 $deleteResult->value = $logId;
1399                 return $deleteResult;
1400         }
1401
1402         /**
1403          * Lists those tags which core or extensions report as being "active".
1404          *
1405          * @return array
1406          * @since 1.25
1407          */
1408         public static function listSoftwareActivatedTags() {
1409                 // core active tags
1410                 $tags = self::getSoftwareTags();
1411                 if ( !Hooks::isRegistered( 'ChangeTagsListActive' ) ) {
1412                         return $tags;
1413                 }
1414                 $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
1415                 return $cache->getWithSetCallback(
1416                         $cache->makeKey( 'active-tags' ),
1417                         WANObjectCache::TTL_MINUTE * 5,
1418                         function ( $oldValue, &$ttl, array &$setOpts ) use ( $tags ) {
1419                                 $setOpts += Database::getCacheSetOptions( wfGetDB( DB_REPLICA ) );
1420
1421                                 // Ask extensions which tags they consider active
1422                                 Hooks::run( 'ChangeTagsListActive', [ &$tags ] );
1423                                 return $tags;
1424                         },
1425                         [
1426                                 'checkKeys' => [ $cache->makeKey( 'active-tags' ) ],
1427                                 'lockTSE' => WANObjectCache::TTL_MINUTE * 5,
1428                                 'pcTTL' => WANObjectCache::TTL_PROC_LONG
1429                         ]
1430                 );
1431         }
1432
1433         /**
1434          * Basically lists defined tags which count even if they aren't applied to anything.
1435          * It returns a union of the results of listExplicitlyDefinedTags()
1436          *
1437          * @return string[] Array of strings: tags
1438          */
1439         public static function listDefinedTags() {
1440                 $tags1 = self::listExplicitlyDefinedTags();
1441                 $tags2 = self::listSoftwareDefinedTags();
1442                 return array_values( array_unique( array_merge( $tags1, $tags2 ) ) );
1443         }
1444
1445         /**
1446          * Lists tags explicitly defined in the `valid_tag` table of the database.
1447          * Tags in table 'change_tag' which are not in table 'valid_tag' are not
1448          * included.
1449          *
1450          * Tries memcached first.
1451          *
1452          * @return string[] Array of strings: tags
1453          * @since 1.25
1454          */
1455         public static function listExplicitlyDefinedTags() {
1456                 $fname = __METHOD__;
1457
1458                 $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
1459                 return $cache->getWithSetCallback(
1460                         $cache->makeKey( 'valid-tags-db' ),
1461                         WANObjectCache::TTL_MINUTE * 5,
1462                         function ( $oldValue, &$ttl, array &$setOpts ) use ( $fname ) {
1463                                 $dbr = wfGetDB( DB_REPLICA );
1464
1465                                 $setOpts += Database::getCacheSetOptions( $dbr );
1466
1467                                 $tags = $dbr->selectFieldValues( 'valid_tag', 'vt_tag', [], $fname );
1468
1469                                 return array_filter( array_unique( $tags ) );
1470                         },
1471                         [
1472                                 'checkKeys' => [ $cache->makeKey( 'valid-tags-db' ) ],
1473                                 'lockTSE' => WANObjectCache::TTL_MINUTE * 5,
1474                                 'pcTTL' => WANObjectCache::TTL_PROC_LONG
1475                         ]
1476                 );
1477         }
1478
1479         /**
1480          * Lists tags defined by core or extensions using the ListDefinedTags hook.
1481          * Extensions need only define those tags they deem to be in active use.
1482          *
1483          * Tries memcached first.
1484          *
1485          * @return string[] Array of strings: tags
1486          * @since 1.25
1487          */
1488         public static function listSoftwareDefinedTags() {
1489                 // core defined tags
1490                 $tags = self::getSoftwareTags( true );
1491                 if ( !Hooks::isRegistered( 'ListDefinedTags' ) ) {
1492                         return $tags;
1493                 }
1494                 $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
1495                 return $cache->getWithSetCallback(
1496                         $cache->makeKey( 'valid-tags-hook' ),
1497                         WANObjectCache::TTL_MINUTE * 5,
1498                         function ( $oldValue, &$ttl, array &$setOpts ) use ( $tags ) {
1499                                 $setOpts += Database::getCacheSetOptions( wfGetDB( DB_REPLICA ) );
1500
1501                                 Hooks::run( 'ListDefinedTags', [ &$tags ] );
1502                                 return array_filter( array_unique( $tags ) );
1503                         },
1504                         [
1505                                 'checkKeys' => [ $cache->makeKey( 'valid-tags-hook' ) ],
1506                                 'lockTSE' => WANObjectCache::TTL_MINUTE * 5,
1507                                 'pcTTL' => WANObjectCache::TTL_PROC_LONG
1508                         ]
1509                 );
1510         }
1511
1512         /**
1513          * Invalidates the short-term cache of defined tags used by the
1514          * list*DefinedTags functions, as well as the tag statistics cache.
1515          * @since 1.25
1516          */
1517         public static function purgeTagCacheAll() {
1518                 $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
1519
1520                 $cache->touchCheckKey( $cache->makeKey( 'active-tags' ) );
1521                 $cache->touchCheckKey( $cache->makeKey( 'valid-tags-db' ) );
1522                 $cache->touchCheckKey( $cache->makeKey( 'valid-tags-hook' ) );
1523
1524                 self::purgeTagUsageCache();
1525         }
1526
1527         /**
1528          * Invalidates the tag statistics cache only.
1529          * @since 1.25
1530          */
1531         public static function purgeTagUsageCache() {
1532                 $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
1533
1534                 $cache->touchCheckKey( $cache->makeKey( 'change-tag-statistics' ) );
1535         }
1536
1537         /**
1538          * Returns a map of any tags used on the wiki to number of edits
1539          * tagged with them, ordered descending by the hitcount.
1540          * This does not include tags defined somewhere that have never been applied.
1541          *
1542          * Keeps a short-term cache in memory, so calling this multiple times in the
1543          * same request should be fine.
1544          *
1545          * @return array Array of string => int
1546          */
1547         public static function tagUsageStatistics() {
1548                 global $wgChangeTagsSchemaMigrationStage, $wgTagStatisticsNewTable;
1549                 if ( $wgChangeTagsSchemaMigrationStage > MIGRATION_WRITE_BOTH ||
1550                         ( $wgTagStatisticsNewTable && $wgChangeTagsSchemaMigrationStage > MIGRATION_OLD )
1551                 ) {
1552                         return self::newTagUsageStatistics();
1553                 }
1554
1555                 $fname = __METHOD__;
1556                 $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
1557                 return $cache->getWithSetCallback(
1558                         $cache->makeKey( 'change-tag-statistics' ),
1559                         WANObjectCache::TTL_MINUTE * 5,
1560                         function ( $oldValue, &$ttl, array &$setOpts ) use ( $fname ) {
1561                                 $dbr = wfGetDB( DB_REPLICA, 'vslow' );
1562
1563                                 $setOpts += Database::getCacheSetOptions( $dbr );
1564
1565                                 $res = $dbr->select(
1566                                         'change_tag',
1567                                         [ 'ct_tag', 'hitcount' => 'count(*)' ],
1568                                         [],
1569                                         $fname,
1570                                         [ 'GROUP BY' => 'ct_tag', 'ORDER BY' => 'hitcount DESC' ]
1571                                 );
1572
1573                                 $out = [];
1574                                 foreach ( $res as $row ) {
1575                                         $out[$row->ct_tag] = $row->hitcount;
1576                                 }
1577
1578                                 return $out;
1579                         },
1580                         [
1581                                 'checkKeys' => [ $cache->makeKey( 'change-tag-statistics' ) ],
1582                                 'lockTSE' => WANObjectCache::TTL_MINUTE * 5,
1583                                 'pcTTL' => WANObjectCache::TTL_PROC_LONG
1584                         ]
1585                 );
1586         }
1587
1588         /**
1589          * Same self::tagUsageStatistics() but uses change_tag_def.
1590          *
1591          * @return array Array of string => int
1592          */
1593         private static function newTagUsageStatistics() {
1594                 $dbr = wfGetDB( DB_REPLICA );
1595                 $res = $dbr->select(
1596                         'change_tag_def',
1597                         [ 'ctd_name', 'ctd_count' ],
1598                         [],
1599                         __METHOD__,
1600                         [ 'ORDER BY' => 'ctd_count DESC' ]
1601                 );
1602
1603                 $out = [];
1604                 foreach ( $res as $row ) {
1605                         $out[$row->ctd_name] = $row->ctd_count;
1606                 }
1607
1608                 return $out;
1609         }
1610
1611         /**
1612          * Indicate whether change tag editing UI is relevant
1613          *
1614          * Returns true if the user has the necessary right and there are any
1615          * editable tags defined.
1616          *
1617          * This intentionally doesn't check "any addable || any deletable", because
1618          * it seems like it would be more confusing than useful if the checkboxes
1619          * suddenly showed up because some abuse filter stopped defining a tag and
1620          * then suddenly disappeared when someone deleted all uses of that tag.
1621          *
1622          * @param User $user
1623          * @return bool
1624          */
1625         public static function showTagEditingUI( User $user ) {
1626                 return $user->isAllowed( 'changetags' ) && (bool)self::listExplicitlyDefinedTags();
1627         }
1628 }