includes/changetags/ChangeTags.php

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