includes/changetags/ChangeTags.php

   1 <?php
   2 /**
   3  * Recent changes tagging.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  * @ingroup Change tagging
  22  */
  23
  24 use MediaWiki\MediaWikiServices;
  25 use MediaWiki\Storage\NameTableAccessException;
  26 use Wikimedia\Rdbms\Database;
  27
  28 class ChangeTags {
  29         /**
  30          * Can't delete tags with more than this many uses. Similar in intent to
  31          * the bigdelete user right
  32          * @todo Use the job queue for tag deletion to avoid this restriction
  33          */
  34         const MAX_DELETE_USES = 5000;
  35
  36         /**
  37          * A list of tags defined and used by MediaWiki itself.
  38          */
  39         private static $definedSoftwareTags = [
  40                 'mw-contentmodelchange',
  41                 'mw-new-redirect',
  42                 'mw-removed-redirect',
  43                 'mw-changed-redirect-target',
  44                 'mw-blank',
  45                 'mw-replace',
  46                 'mw-rollback',
  47                 'mw-undo',
  48         ];
  49
  50         /**
  51          * Loads defined core tags, checks for invalid types (if not array),
  52          * and filters for supported and enabled (if $all is false) tags only.
  53          *
  54          * @param bool $all If true, return all valid defined tags. Otherwise, return only enabled ones.
  55          * @return array Array of all defined/enabled tags.
  56          */
  57         public static function getSoftwareTags( $all = false ) {
  58                 global $wgSoftwareTags;
  59                 $softwareTags = [];
  60
  61                 if ( !is_array( $wgSoftwareTags ) ) {
  62                         wfWarn( 'wgSoftwareTags should be associative array of enabled tags.
  63                         Please refer to documentation for the list of tags you can enable' );
  64                         return $softwareTags;
  65                 }
  66
  67                 $availableSoftwareTags = !$all ?
  68                         array_keys( array_filter( $wgSoftwareTags ) ) :
  69                         array_keys( $wgSoftwareTags );
  70
  71                 $softwareTags = array_intersect(
  72                         $availableSoftwareTags,
  73                         self::$definedSoftwareTags
  74                 );
  75
  76                 return $softwareTags;
  77         }
  78
  79         /**
  80          * Creates HTML for the given tags
  81          *
  82          * @param string $tags Comma-separated list of tags
  83          * @param string $page A label for the type of action which is being displayed,
  84          *   for example: 'history', 'contributions' or 'newpages'
  85          * @param IContextSource|null $context
  86          * @note Even though it takes null as a valid argument, an IContextSource is preferred
  87          *       in a new code, as the null value is subject to change in the future
  88          * @return array Array with two items: (html, classes)
  89          *   - html: String: HTML for displaying the tags (empty string when param $tags is empty)
  90          *   - classes: Array of strings: CSS classes used in the generated html, one class for each tag
  91          * @return-taint onlysafefor_htmlnoent
  92          */
  93         public static function formatSummaryRow( $tags, $page, IContextSource $context = null ) {
  94                 if ( !$tags ) {
  95                         return [ '', [] ];
  96                 }
  97                 if ( !$context ) {
  98                         $context = RequestContext::getMain();
  99                 }
 100
 101                 $classes = [];
 102
 103                 $tags = explode( ',', $tags );
 104                 $displayTags = [];
 105                 foreach ( $tags as $tag ) {
 106                         if ( !$tag ) {
 107                                 continue;
 108                         }
 109                         $description = self::tagDescription( $tag, $context );
 110                         if ( $description === false ) {
 111                                 continue;
 112                         }
 113                         $displayTags[] = Xml::tags(
 114                                 'span',
 115                                 [ 'class' => 'mw-tag-marker ' .
 116                                                                 Sanitizer::escapeClass( "mw-tag-marker-$tag" ) ],
 117                                 $description
 118                         );
 119                         $classes[] = Sanitizer::escapeClass( "mw-tag-$tag" );
 120                 }
 121
 122                 if ( !$displayTags ) {
 123                         return [ '', [] ];
 124                 }
 125
 126                 $markers = $context->msg( 'tag-list-wrapper' )
 127                         ->numParams( count( $displayTags ) )
 128                         ->rawParams( $context->getLanguage()->commaList( $displayTags ) )
 129                         ->parse();
 130                 $markers = Xml::tags( 'span', [ 'class' => 'mw-tag-markers' ], $markers );
 131
 132                 return [ $markers, $classes ];
 133         }
 134
 135         /**
 136          * Get a short description for a tag.
 137          *
 138          * Checks if message key "mediawiki:tag-$tag" exists. If it does not,
 139          * returns the HTML-escaped tag name. Uses the message if the message
 140          * exists, provided it is not disabled. If the message is disabled,
 141          * we consider the tag hidden, and return false.
 142          *
 143          * @param string $tag
 144          * @param IContextSource $context
 145          * @return string|bool Tag description or false if tag is to be hidden.
 146          * @since 1.25 Returns false if tag is to be hidden.
 147          */
 148         public static function tagDescription( $tag, IContextSource $context ) {
 149                 $msg = $context->msg( "tag-$tag" );
 150                 if ( !$msg->exists() ) {
 151                         // No such message, so return the HTML-escaped tag name.
 152                         return htmlspecialchars( $tag );
 153                 }
 154                 if ( $msg->isDisabled() ) {
 155                         // The message exists but is disabled, hide the tag.
 156                         return false;
 157                 }
 158
 159                 // Message exists and isn't disabled, use it.
 160                 return $msg->parse();
 161         }
 162
 163         /**
 164          * Get the message object for the tag's long description.
 165          *
 166          * Checks if message key "mediawiki:tag-$tag-description" exists. If it does not,
 167          * or if message is disabled, returns false. Otherwise, returns the message object
 168          * for the long description.
 169          *
 170          * @param string $tag
 171          * @param IContextSource $context
 172          * @return Message|bool Message object of the tag long description or false if
 173          *  there is no description.
 174          */
 175         public static function tagLongDescriptionMessage( $tag, IContextSource $context ) {
 176                 $msg = $context->msg( "tag-$tag-description" );
 177                 if ( !$msg->exists() ) {
 178                         return false;
 179                 }
 180                 if ( $msg->isDisabled() ) {
 181                         // The message exists but is disabled, hide the description.
 182                         return false;
 183                 }
 184
 185                 // Message exists and isn't disabled, use it.
 186                 return $msg;
 187         }
 188
 189         /**
 190          * Get truncated message for the tag's long description.
 191          *
 192          * @param string $tag Tag name.
 193          * @param int $length Maximum length of truncated message, including ellipsis.
 194          * @param IContextSource $context
 195          *
 196          * @return string Truncated long tag description.
 197          */
 198         public static function truncateTagDescription( $tag, $length, IContextSource $context ) {
 199                 $originalDesc = self::tagLongDescriptionMessage( $tag, $context );
 200                 // If there is no tag description, return empty string
 201                 if ( !$originalDesc ) {
 202                         return '';
 203                 }
 204
 205                 $taglessDesc = Sanitizer::stripAllTags( $originalDesc->parse() );
 206
 207                 return $context->getLanguage()->truncateForVisual( $taglessDesc, $length );
 208         }
 209
 210         /**
 211          * Add tags to a change given its rc_id, rev_id and/or log_id
 212          *
 213          * @param string|string[] $tags Tags to add to the change
 214          * @param int|null $rc_id The rc_id of the change to add the tags to
 215          * @param int|null $rev_id The rev_id of the change to add the tags to
 216          * @param int|null $log_id The log_id of the change to add the tags to
 217          * @param string|null $params Params to put in the ct_params field of table 'change_tag'
 218          * @param RecentChange|null $rc Recent change, in case the tagging accompanies the action
 219          * (this should normally be the case)
 220          *
 221          * @throws MWException
 222          * @return bool False if no changes are made, otherwise true
 223          */
 224         public static function addTags( $tags, $rc_id = null, $rev_id = null,
 225                 $log_id = null, $params = null, RecentChange $rc = null
 226         ) {
 227                 $result = self::updateTags( $tags, null, $rc_id, $rev_id, $log_id, $params, $rc );
 228                 return (bool)$result[0];
 229         }
 230
 231         /**
 232          * Add and remove tags to/from a change given its rc_id, rev_id and/or log_id,
 233          * without verifying that the tags exist or are valid. If a tag is present in
 234          * both $tagsToAdd and $tagsToRemove, it will be removed.
 235          *
 236          * This function should only be used by extensions to manipulate tags they
 237          * have registered using the ListDefinedTags hook. When dealing with user
 238          * input, call updateTagsWithChecks() instead.
 239          *
 240          * @param string|array|null $tagsToAdd Tags to add to the change
 241          * @param string|array|null $tagsToRemove Tags to remove from the change
 242          * @param int|null &$rc_id The rc_id of the change to add the tags to.
 243          * Pass a variable whose value is null if the rc_id is not relevant or unknown.
 244          * @param int|null &$rev_id The rev_id of the change to add the tags to.
 245          * Pass a variable whose value is null if the rev_id is not relevant or unknown.
 246          * @param int|null &$log_id The log_id of the change to add the tags to.
 247          * Pass a variable whose value is null if the log_id is not relevant or unknown.
 248          * @param string|null $params Params to put in the ct_params field of table
 249          * 'change_tag' when adding tags
 250          * @param RecentChange|null $rc Recent change being tagged, in case the tagging accompanies
 251          * the action
 252          * @param User|null $user Tagging user, in case the tagging is subsequent to the tagged action
 253          *
 254          * @throws MWException When $rc_id, $rev_id and $log_id are all null
 255          * @return array Index 0 is an array of tags actually added, index 1 is an
 256          * array of tags actually removed, index 2 is an array of tags present on the
 257          * revision or log entry before any changes were made
 258          *
 259          * @since 1.25
 260          */
 261         public static function updateTags( $tagsToAdd, $tagsToRemove, &$rc_id = null,
 262                 &$rev_id = null, &$log_id = null, $params = null, RecentChange $rc = null,
 263                 User $user = null
 264         ) {
 265                 global $wgChangeTagsSchemaMigrationStage;
 266
 267                 $tagsToAdd = array_filter( (array)$tagsToAdd ); // Make sure we're submitting all tags...
 268                 $tagsToRemove = array_filter( (array)$tagsToRemove );
 269
 270                 if ( !$rc_id && !$rev_id && !$log_id ) {
 271                         throw new MWException( 'At least one of: RCID, revision ID, and log ID MUST be ' .
 272                                 'specified when adding or removing a tag from a change!' );
 273                 }
 274
 275                 $dbw = wfGetDB( DB_MASTER );
 276
 277                 // Might as well look for rcids and so on.
 278                 if ( !$rc_id ) {
 279                         // Info might be out of date, somewhat fractionally, on replica DB.
 280                         // LogEntry/LogPage and WikiPage match rev/log/rc timestamps,
 281                         // so use that relation to avoid full table scans.
 282                         if ( $log_id ) {
 283                                 $rc_id = $dbw->selectField(
 284                                         [ 'logging', 'recentchanges' ],
 285                                         'rc_id',
 286                                         [
 287                                                 'log_id' => $log_id,
 288                                                 'rc_timestamp = log_timestamp',
 289                                                 'rc_logid = log_id'
 290                                         ],
 291                                         __METHOD__
 292                                 );
 293                         } elseif ( $rev_id ) {
 294                                 $rc_id = $dbw->selectField(
 295                                         [ 'revision', 'recentchanges' ],
 296                                         'rc_id',
 297                                         [
 298                                                 'rev_id' => $rev_id,
 299                                                 'rc_timestamp = rev_timestamp',
 300                                                 'rc_this_oldid = rev_id'
 301                                         ],
 302                                         __METHOD__
 303                                 );
 304                         }
 305                 } elseif ( !$log_id && !$rev_id ) {
 306                         // Info might be out of date, somewhat fractionally, on replica DB.
 307                         $log_id = $dbw->selectField(
 308                                 'recentchanges',
 309                                 'rc_logid',
 310                                 [ 'rc_id' => $rc_id ],
 311                                 __METHOD__
 312                         );
 313                         $rev_id = $dbw->selectField(
 314                                 'recentchanges',
 315                                 'rc_this_oldid',
 316                                 [ 'rc_id' => $rc_id ],
 317                                 __METHOD__
 318                         );
 319                 }
 320
 321                 if ( $log_id && !$rev_id ) {
 322                         $rev_id = $dbw->selectField(
 323                                 'log_search',
 324                                 'ls_value',
 325                                 [ 'ls_field' => 'associated_rev_id', 'ls_log_id' => $log_id ],
 326                                 __METHOD__
 327                         );
 328                 } elseif ( !$log_id && $rev_id ) {
 329                         $log_id = $dbw->selectField(
 330                                 'log_search',
 331                                 'ls_log_id',
 332                                 [ 'ls_field' => 'associated_rev_id', 'ls_value' => $rev_id ],
 333                                 __METHOD__
 334                         );
 335                 }
 336
 337                 // update the tag_summary row
 338                 $prevTags = [];
 339                 if ( !self::updateTagSummaryRow( $tagsToAdd, $tagsToRemove, $rc_id, $rev_id,
 340                         $log_id, $prevTags )
 341                 ) {
 342                         // nothing to do
 343                         return [ [], [], $prevTags ];
 344                 }
 345
 346                 // insert a row into change_tag for each new tag
 347                 $changeTagDefStore = MediaWikiServices::getInstance()->getChangeTagDefStore();
 348                 if ( count( $tagsToAdd ) ) {
 349                         $changeTagMapping = [];
 350                         if ( $wgChangeTagsSchemaMigrationStage > MIGRATION_OLD ) {
 351                                 foreach ( $tagsToAdd as $tag ) {
 352                                         $changeTagMapping[$tag] = $changeTagDefStore->acquireId( $tag );
 353                                 }
 354
 355                                 $dbw->update(
 356                                         'change_tag_def',
 357                                         [ 'ctd_count = ctd_count + 1' ],
 358                                         [ 'ctd_name' => $tagsToAdd ],
 359                                         __METHOD__
 360                                 );
 361                         }
 362
 363                         $tagsRows = [];
 364                         foreach ( $tagsToAdd as $tag ) {
 365                                 if ( $wgChangeTagsSchemaMigrationStage > MIGRATION_WRITE_BOTH ) {
 366                                         $tagName = null;
 367                                 } else {
 368                                         $tagName = $tag;
 369                                 }
 370                                 // Filter so we don't insert NULLs as zero accidentally.
 371                                 // Keep in mind that $rc_id === null means "I don't care/know about the
 372                                 // rc_id, just delete $tag on this revision/log entry". It doesn't
 373                                 // mean "only delete tags on this revision/log WHERE rc_id IS NULL".
 374                                 $tagsRows[] = array_filter(
 375                                         [
 376                                                 'ct_tag' => $tagName,
 377                                                 'ct_rc_id' => $rc_id,
 378                                                 'ct_log_id' => $log_id,
 379                                                 'ct_rev_id' => $rev_id,
 380                                                 'ct_params' => $params,
 381                                                 'ct_tag_id' => $changeTagMapping[$tag] ?? null,
 382                                         ]
 383                                 );
 384
 385                         }
 386
 387                         $dbw->insert( 'change_tag', $tagsRows, __METHOD__, [ 'IGNORE' ] );
 388                 }
 389
 390                 // delete from change_tag
 391                 if ( count( $tagsToRemove ) ) {
 392                         foreach ( $tagsToRemove as $tag ) {
 393                                 if ( $wgChangeTagsSchemaMigrationStage > MIGRATION_WRITE_BOTH ) {
 394                                         $tagName = null;
 395                                         $tagId = $changeTagDefStore->getId( $tag );
 396                                 } else {
 397                                         $tagName = $tag;
 398                                         $tagId = null;
 399                                 }
 400                                 $conds = array_filter(
 401                                         [
 402                                                 'ct_tag' => $tagName,
 403                                                 'ct_rc_id' => $rc_id,
 404                                                 'ct_log_id' => $log_id,
 405                                                 'ct_rev_id' => $rev_id,
 406                                                 'ct_tag_id' => $tagId,
 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, $wgChangeTagsSchemaMigrationStage;
 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                 $tagTables[] = 'change_tag';
 808                 if ( $wgChangeTagsSchemaMigrationStage > MIGRATION_WRITE_BOTH ) {
 809                         $tagTables[] = 'change_tag_def';
 810                         $join_cond_ts_tags = [ $join_cond, 'ct_tag_id=ctd_id' ];
 811                         $field = 'ctd_name';
 812                 } else {
 813                         $field = 'ct_tag';
 814                         $join_cond_ts_tags = $join_cond;
 815                 }
 816
 817                 $fields['ts_tags'] = wfGetDB( DB_REPLICA )->buildGroupConcatField(
 818                         ',', $tagTables, $field, $join_cond_ts_tags
 819                 );
 820
 821                 if ( $wgUseTagFilter && $filter_tag ) {
 822                         // Somebody wants to filter on a tag.
 823                         // Add an INNER JOIN on change_tag
 824
 825                         $tables[] = 'change_tag';
 826                         $join_conds['change_tag'] = [ 'INNER JOIN', $join_cond ];
 827                         if ( $wgChangeTagsSchemaMigrationStage > MIGRATION_WRITE_BOTH ) {
 828                                 $filterTagIds = [];
 829                                 $changeTagDefStore = MediaWikiServices::getInstance()->getChangeTagDefStore();
 830                                 foreach ( (array)$filter_tag as $filterTagName ) {
 831                                         try {
 832                                                 $filterTagIds[] = $changeTagDefStore->getId( $filterTagName );
 833                                         } catch ( NameTableAccessException $exception ) {
 834                                                 // Return nothing.
 835                                                 $conds[] = '0';
 836                                                 break;
 837                                         };
 838                                 }
 839                                 $conds['ct_tag_id'] = $filterTagIds;
 840                         } else {
 841                                 $conds['ct_tag'] = $filter_tag;
 842                         }
 843
 844                         if (
 845                                 is_array( $filter_tag ) && count( $filter_tag ) > 1 &&
 846                                 !in_array( 'DISTINCT', $options )
 847                         ) {
 848                                 $options[] = 'DISTINCT';
 849                         }
 850                 }
 851         }
 852
 853         /**
 854          * Build a text box to select a change tag
 855          *
 856          * @param string $selected Tag to select by default
 857          * @param bool $ooui Use an OOUI TextInputWidget as selector instead of a non-OOUI input field
 858          *        You need to call OutputPage::enableOOUI() yourself.
 859          * @param IContextSource|null $context
 860          * @note Even though it takes null as a valid argument, an IContextSource is preferred
 861          *       in a new code, as the null value can change in the future
 862          * @return array an array of (label, selector)
 863          */
 864         public static function buildTagFilterSelector(
 865                 $selected = '', $ooui = false, IContextSource $context = null
 866         ) {
 867                 if ( !$context ) {
 868                         $context = RequestContext::getMain();
 869                 }
 870
 871                 $config = $context->getConfig();
 872                 if ( !$config->get( 'UseTagFilter' ) || !count( self::listDefinedTags() ) ) {
 873                         return [];
 874                 }
 875
 876                 $data = [
 877                         Html::rawElement(
 878                                 'label',
 879                                 [ 'for' => 'tagfilter' ],
 880                                 $context->msg( 'tag-filter' )->parse()
 881                         )
 882                 ];
 883
 884                 if ( $ooui ) {
 885                         $data[] = new OOUI\TextInputWidget( [
 886                                 'id' => 'tagfilter',
 887                                 'name' => 'tagfilter',
 888                                 'value' => $selected,
 889                                 'classes' => 'mw-tagfilter-input',
 890                         ] );
 891                 } else {
 892                         $data[] = Xml::input(
 893                                 'tagfilter',
 894                                 20,
 895                                 $selected,
 896                                 [ 'class' => 'mw-tagfilter-input mw-ui-input mw-ui-input-inline', 'id' => 'tagfilter' ]
 897                         );
 898                 }
 899
 900                 return $data;
 901         }
 902
 903         /**
 904          * Defines a tag in the valid_tag table and/or update ctd_user_defined field in change_tag_def,
 905          * without checking that the tag name is valid.
 906          * Extensions should NOT use this function; they can use the ListDefinedTags
 907          * hook instead.
 908          *
 909          * @param string $tag Tag to create
 910          * @since 1.25
 911          */
 912         public static function defineTag( $tag ) {
 913                 global $wgChangeTagsSchemaMigrationStage;
 914
 915                 $dbw = wfGetDB( DB_MASTER );
 916                 if ( $wgChangeTagsSchemaMigrationStage > MIGRATION_OLD ) {
 917                         $tagDef = [
 918                                 'ctd_name' => $tag,
 919                                 'ctd_user_defined' => 1,
 920                                 'ctd_count' => 0
 921                         ];
 922                         $dbw->upsert(
 923                                 'change_tag_def',
 924                                 $tagDef,
 925                                 [ 'ctd_name' ],
 926                                 [ 'ctd_user_defined' => 1 ],
 927                                 __METHOD__
 928                         );
 929                 }
 930
 931                 $dbw->replace(
 932                         'valid_tag',
 933                         [ 'vt_tag' ],
 934                         [ 'vt_tag' => $tag ],
 935                         __METHOD__
 936                 );
 937
 938                 // clear the memcache of defined tags
 939                 self::purgeTagCacheAll();
 940         }
 941
 942         /**
 943          * Removes a tag from the valid_tag table and/or update ctd_user_defined field in change_tag_def.
 944          * The tag may remain in use by extensions, and may still show up as 'defined'
 945          * if an extension is setting it from the ListDefinedTags hook.
 946          *
 947          * @param string $tag Tag to remove
 948          * @since 1.25
 949          */
 950         public static function undefineTag( $tag ) {
 951                 global $wgChangeTagsSchemaMigrationStage;
 952
 953                 $dbw = wfGetDB( DB_MASTER );
 954
 955                 if ( $wgChangeTagsSchemaMigrationStage > MIGRATION_OLD ) {
 956                         $dbw->update(
 957                                 'change_tag_def',
 958                                 [ 'ctd_user_defined' => 0 ],
 959                                 [ 'ctd_name' => $tag ],
 960                                 __METHOD__
 961                         );
 962
 963                         $dbw->delete(
 964                                 'change_tag_def',
 965                                 [ 'ctd_name' => $tag, 'ctd_count' => 0 ],
 966                                 __METHOD__
 967                         );
 968                 }
 969
 970                 $dbw->delete( 'valid_tag', [ 'vt_tag' => $tag ], __METHOD__ );
 971
 972                 // clear the memcache of defined tags
 973                 self::purgeTagCacheAll();
 974         }
 975
 976         /**
 977          * Writes a tag action into the tag management log.
 978          *
 979          * @param string $action
 980          * @param string $tag
 981          * @param string $reason
 982          * @param User $user Who to attribute the action to
 983          * @param int|null $tagCount For deletion only, how many usages the tag had before
 984          * it was deleted.
 985          * @param array $logEntryTags Change tags to apply to the entry
 986          * that will be created in the tag management log
 987          * @return int ID of the inserted log entry
 988          * @since 1.25
 989          */
 990         protected static function logTagManagementAction( $action, $tag, $reason,
 991                 User $user, $tagCount = null, array $logEntryTags = []
 992         ) {
 993                 $dbw = wfGetDB( DB_MASTER );
 994
 995                 $logEntry = new ManualLogEntry( 'managetags', $action );
 996                 $logEntry->setPerformer( $user );
 997                 // target page is not relevant, but it has to be set, so we just put in
 998                 // the title of Special:Tags
 999                 $logEntry->setTarget( Title::newFromText( 'Special:Tags' ) );
1000                 $logEntry->setComment( $reason );
1001
1002                 $params = [ '4::tag' => $tag ];
1003                 if ( !is_null( $tagCount ) ) {
1004                         $params['5:number:count'] = $tagCount;
1005                 }
1006                 $logEntry->setParameters( $params );
1007                 $logEntry->setRelations( [ 'Tag' => $tag ] );
1008                 $logEntry->setTags( $logEntryTags );
1009
1010                 $logId = $logEntry->insert( $dbw );
1011                 $logEntry->publish( $logId );
1012                 return $logId;
1013         }
1014
1015         /**
1016          * Is it OK to allow the user to activate this tag?
1017          *
1018          * @param string $tag Tag that you are interested in activating
1019          * @param User|null $user User whose permission you wish to check, or null if
1020          * you don't care (e.g. maintenance scripts)
1021          * @return Status
1022          * @since 1.25
1023          */
1024         public static function canActivateTag( $tag, User $user = null ) {
1025                 if ( !is_null( $user ) ) {
1026                         if ( !$user->isAllowed( 'managechangetags' ) ) {
1027                                 return Status::newFatal( 'tags-manage-no-permission' );
1028                         } elseif ( $user->isBlocked() ) {
1029                                 return Status::newFatal( 'tags-manage-blocked', $user->getName() );
1030                         }
1031                 }
1032
1033                 // defined tags cannot be activated (a defined tag is either extension-
1034                 // defined, in which case the extension chooses whether or not to active it;
1035                 // or user-defined, in which case it is considered active)
1036                 $definedTags = self::listDefinedTags();
1037                 if ( in_array( $tag, $definedTags ) ) {
1038                         return Status::newFatal( 'tags-activate-not-allowed', $tag );
1039                 }
1040
1041                 // non-existing tags cannot be activated
1042                 $tagUsage = self::tagUsageStatistics();
1043                 if ( !isset( $tagUsage[$tag] ) ) { // we already know the tag is undefined
1044                         return Status::newFatal( 'tags-activate-not-found', $tag );
1045                 }
1046
1047                 return Status::newGood();
1048         }
1049
1050         /**
1051          * Activates a tag, checking whether it is allowed first, and adding a log
1052          * entry afterwards.
1053          *
1054          * Includes a call to ChangeTag::canActivateTag(), so your code doesn't need
1055          * to do that.
1056          *
1057          * @param string $tag
1058          * @param string $reason
1059          * @param User $user Who to give credit for the action
1060          * @param bool $ignoreWarnings Can be used for API interaction, default false
1061          * @param array $logEntryTags Change tags to apply to the entry
1062          * that will be created in the tag management log
1063          * @return Status If successful, the Status contains the ID of the added log
1064          * entry as its value
1065          * @since 1.25
1066          */
1067         public static function activateTagWithChecks( $tag, $reason, User $user,
1068                 $ignoreWarnings = false, array $logEntryTags = []
1069         ) {
1070                 // are we allowed to do this?
1071                 $result = self::canActivateTag( $tag, $user );
1072                 if ( $ignoreWarnings ? !$result->isOK() : !$result->isGood() ) {
1073                         $result->value = null;
1074                         return $result;
1075                 }
1076
1077                 // do it!
1078                 self::defineTag( $tag );
1079
1080                 // log it
1081                 $logId = self::logTagManagementAction( 'activate', $tag, $reason, $user,
1082                         null, $logEntryTags );
1083
1084                 return Status::newGood( $logId );
1085         }
1086
1087         /**
1088          * Is it OK to allow the user to deactivate this tag?
1089          *
1090          * @param string $tag Tag that you are interested in deactivating
1091          * @param User|null $user User whose permission you wish to check, or null if
1092          * you don't care (e.g. maintenance scripts)
1093          * @return Status
1094          * @since 1.25
1095          */
1096         public static function canDeactivateTag( $tag, User $user = null ) {
1097                 if ( !is_null( $user ) ) {
1098                         if ( !$user->isAllowed( 'managechangetags' ) ) {
1099                                 return Status::newFatal( 'tags-manage-no-permission' );
1100                         } elseif ( $user->isBlocked() ) {
1101                                 return Status::newFatal( 'tags-manage-blocked', $user->getName() );
1102                         }
1103                 }
1104
1105                 // only explicitly-defined tags can be deactivated
1106                 $explicitlyDefinedTags = self::listExplicitlyDefinedTags();
1107                 if ( !in_array( $tag, $explicitlyDefinedTags ) ) {
1108                         return Status::newFatal( 'tags-deactivate-not-allowed', $tag );
1109                 }
1110                 return Status::newGood();
1111         }
1112
1113         /**
1114          * Deactivates a tag, checking whether it is allowed first, and adding a log
1115          * entry afterwards.
1116          *
1117          * Includes a call to ChangeTag::canDeactivateTag(), so your code doesn't need
1118          * to do that.
1119          *
1120          * @param string $tag
1121          * @param string $reason
1122          * @param User $user Who to give credit for the action
1123          * @param bool $ignoreWarnings Can be used for API interaction, default false
1124          * @param array $logEntryTags Change tags to apply to the entry
1125          * that will be created in the tag management log
1126          * @return Status If successful, the Status contains the ID of the added log
1127          * entry as its value
1128          * @since 1.25
1129          */
1130         public static function deactivateTagWithChecks( $tag, $reason, User $user,
1131                 $ignoreWarnings = false, array $logEntryTags = []
1132         ) {
1133                 // are we allowed to do this?
1134                 $result = self::canDeactivateTag( $tag, $user );
1135                 if ( $ignoreWarnings ? !$result->isOK() : !$result->isGood() ) {
1136                         $result->value = null;
1137                         return $result;
1138                 }
1139
1140                 // do it!
1141                 self::undefineTag( $tag );
1142
1143                 // log it
1144                 $logId = self::logTagManagementAction( 'deactivate', $tag, $reason, $user,
1145                         null, $logEntryTags );
1146
1147                 return Status::newGood( $logId );
1148         }
1149
1150         /**
1151          * Is the tag name valid?
1152          *
1153          * @param string $tag Tag that you are interested in creating
1154          * @return Status
1155          * @since 1.30
1156          */
1157         public static function isTagNameValid( $tag ) {
1158                 // no empty tags
1159                 if ( $tag === '' ) {
1160                         return Status::newFatal( 'tags-create-no-name' );
1161                 }
1162
1163                 // tags cannot contain commas (used as a delimiter in tag_summary table),
1164                 // pipe (used as a delimiter between multiple tags in
1165                 // SpecialRecentchanges and friends), or slashes (would break tag description messages in
1166                 // MediaWiki namespace)
1167                 if ( strpos( $tag, ',' ) !== false || strpos( $tag, '|' ) !== false
1168                         || strpos( $tag, '/' ) !== false ) {
1169                         return Status::newFatal( 'tags-create-invalid-chars' );
1170                 }
1171
1172                 // could the MediaWiki namespace description messages be created?
1173                 $title = Title::makeTitleSafe( NS_MEDIAWIKI, "Tag-$tag-description" );
1174                 if ( is_null( $title ) ) {
1175                         return Status::newFatal( 'tags-create-invalid-title-chars' );
1176                 }
1177
1178                 return Status::newGood();
1179         }
1180
1181         /**
1182          * Is it OK to allow the user to create this tag?
1183          *
1184          * Extensions should NOT use this function. In most cases, a tag can be
1185          * defined using the ListDefinedTags hook without any checking.
1186          *
1187          * @param string $tag Tag that you are interested in creating
1188          * @param User|null $user User whose permission you wish to check, or null if
1189          * you don't care (e.g. maintenance scripts)
1190          * @return Status
1191          * @since 1.25
1192          */
1193         public static function canCreateTag( $tag, User $user = null ) {
1194                 if ( !is_null( $user ) ) {
1195                         if ( !$user->isAllowed( 'managechangetags' ) ) {
1196                                 return Status::newFatal( 'tags-manage-no-permission' );
1197                         } elseif ( $user->isBlocked() ) {
1198                                 return Status::newFatal( 'tags-manage-blocked', $user->getName() );
1199                         }
1200                 }
1201
1202                 $status = self::isTagNameValid( $tag );
1203                 if ( !$status->isGood() ) {
1204                         return $status;
1205                 }
1206
1207                 // does the tag already exist?
1208                 $tagUsage = self::tagUsageStatistics();
1209                 if ( isset( $tagUsage[$tag] ) || in_array( $tag, self::listDefinedTags() ) ) {
1210                         return Status::newFatal( 'tags-create-already-exists', $tag );
1211                 }
1212
1213                 // check with hooks
1214                 $canCreateResult = Status::newGood();
1215                 Hooks::run( 'ChangeTagCanCreate', [ $tag, $user, &$canCreateResult ] );
1216                 return $canCreateResult;
1217         }
1218
1219         /**
1220          * Creates a tag by adding a row to the `valid_tag` table.
1221          * and/or add it to `change_tag_def` table.
1222          *
1223          * Extensions should NOT use this function; they can use the ListDefinedTags
1224          * hook instead.
1225          *
1226          * Includes a call to ChangeTag::canCreateTag(), so your code doesn't need to
1227          * do that.
1228          *
1229          * @param string $tag
1230          * @param string $reason
1231          * @param User $user Who to give credit for the action
1232          * @param bool $ignoreWarnings Can be used for API interaction, default false
1233          * @param array $logEntryTags Change tags to apply to the entry
1234          * that will be created in the tag management log
1235          * @return Status If successful, the Status contains the ID of the added log
1236          * entry as its value
1237          * @since 1.25
1238          */
1239         public static function createTagWithChecks( $tag, $reason, User $user,
1240                 $ignoreWarnings = false, array $logEntryTags = []
1241         ) {
1242                 // are we allowed to do this?
1243                 $result = self::canCreateTag( $tag, $user );
1244                 if ( $ignoreWarnings ? !$result->isOK() : !$result->isGood() ) {
1245                         $result->value = null;
1246                         return $result;
1247                 }
1248
1249                 // do it!
1250                 self::defineTag( $tag );
1251
1252                 // log it
1253                 $logId = self::logTagManagementAction( 'create', $tag, $reason, $user,
1254                         null, $logEntryTags );
1255
1256                 return Status::newGood( $logId );
1257         }
1258
1259         /**
1260          * Permanently removes all traces of a tag from the DB. Good for removing
1261          * misspelt or temporary tags.
1262          *
1263          * This function should be directly called by maintenance scripts only, never
1264          * by user-facing code. See deleteTagWithChecks() for functionality that can
1265          * safely be exposed to users.
1266          *
1267          * @param string $tag Tag to remove
1268          * @return Status The returned status will be good unless a hook changed it
1269          * @since 1.25
1270          */
1271         public static function deleteTagEverywhere( $tag ) {
1272                 global $wgChangeTagsSchemaMigrationStage;
1273                 $dbw = wfGetDB( DB_MASTER );
1274                 $dbw->startAtomic( __METHOD__ );
1275
1276                 // delete from valid_tag and/or set ctd_user_defined = 0
1277                 self::undefineTag( $tag );
1278
1279                 if ( $wgChangeTagsSchemaMigrationStage > MIGRATION_WRITE_BOTH ) {
1280                         $tagId = MediaWikiServices::getInstance()->getChangeTagDefStore()->getId( $tag );
1281                         $conditions = [ 'ct_tag_id' => $tagId ];
1282                 } else {
1283                         $conditions = [ 'ct_tag' => $tag ];
1284                 }
1285
1286                 // find out which revisions use this tag, so we can delete from tag_summary
1287                 $result = $dbw->select( 'change_tag',
1288                         [ 'ct_rc_id', 'ct_log_id', 'ct_rev_id' ],
1289                         $conditions,
1290                         __METHOD__ );
1291                 foreach ( $result as $row ) {
1292                         // remove the tag from the relevant row of tag_summary
1293                         $tagsToAdd = [];
1294                         $tagsToRemove = [ $tag ];
1295                         self::updateTagSummaryRow( $tagsToAdd, $tagsToRemove, $row->ct_rc_id,
1296                                 $row->ct_rev_id, $row->ct_log_id );
1297                 }
1298
1299                 // delete from change_tag
1300                 if ( $wgChangeTagsSchemaMigrationStage > MIGRATION_WRITE_BOTH ) {
1301                         $tagId = MediaWikiServices::getInstance()->getChangeTagDefStore()->getId( $tag );
1302                         $dbw->delete( 'change_tag', [ 'ct_tag_id' => $tagId ], __METHOD__ );
1303                 } else {
1304                         $dbw->delete( 'change_tag', [ 'ct_tag' => $tag ], __METHOD__ );
1305                 }
1306
1307                 if ( $wgChangeTagsSchemaMigrationStage > MIGRATION_OLD ) {
1308                         $dbw->delete( 'change_tag_def', [ 'ctd_name' => $tag ], __METHOD__ );
1309                 }
1310
1311                 $dbw->endAtomic( __METHOD__ );
1312
1313                 // give extensions a chance
1314                 $status = Status::newGood();
1315                 Hooks::run( 'ChangeTagAfterDelete', [ $tag, &$status ] );
1316                 // let's not allow error results, as the actual tag deletion succeeded
1317                 if ( !$status->isOK() ) {
1318                         wfDebug( 'ChangeTagAfterDelete error condition downgraded to warning' );
1319                         $status->setOK( true );
1320                 }
1321
1322                 // clear the memcache of defined tags
1323                 self::purgeTagCacheAll();
1324
1325                 return $status;
1326         }
1327
1328         /**
1329          * Is it OK to allow the user to delete this tag?
1330          *
1331          * @param string $tag Tag that you are interested in deleting
1332          * @param User|null $user User whose permission you wish to check, or null if
1333          * you don't care (e.g. maintenance scripts)
1334          * @return Status
1335          * @since 1.25
1336          */
1337         public static function canDeleteTag( $tag, User $user = null ) {
1338                 $tagUsage = self::tagUsageStatistics();
1339
1340                 if ( !is_null( $user ) ) {
1341                         if ( !$user->isAllowed( 'deletechangetags' ) ) {
1342                                 return Status::newFatal( 'tags-delete-no-permission' );
1343                         } elseif ( $user->isBlocked() ) {
1344                                 return Status::newFatal( 'tags-manage-blocked', $user->getName() );
1345                         }
1346                 }
1347
1348                 if ( !isset( $tagUsage[$tag] ) && !in_array( $tag, self::listDefinedTags() ) ) {
1349                         return Status::newFatal( 'tags-delete-not-found', $tag );
1350                 }
1351
1352                 if ( isset( $tagUsage[$tag] ) && $tagUsage[$tag] > self::MAX_DELETE_USES ) {
1353                         return Status::newFatal( 'tags-delete-too-many-uses', $tag, self::MAX_DELETE_USES );
1354                 }
1355
1356                 $softwareDefined = self::listSoftwareDefinedTags();
1357                 if ( in_array( $tag, $softwareDefined ) ) {
1358                         // extension-defined tags can't be deleted unless the extension
1359                         // specifically allows it
1360                         $status = Status::newFatal( 'tags-delete-not-allowed' );
1361                 } else {
1362                         // user-defined tags are deletable unless otherwise specified
1363                         $status = Status::newGood();
1364                 }
1365
1366                 Hooks::run( 'ChangeTagCanDelete', [ $tag, $user, &$status ] );
1367                 return $status;
1368         }
1369
1370         /**
1371          * Deletes a tag, checking whether it is allowed first, and adding a log entry
1372          * afterwards.
1373          *
1374          * Includes a call to ChangeTag::canDeleteTag(), so your code doesn't need to
1375          * do that.
1376          *
1377          * @param string $tag
1378          * @param string $reason
1379          * @param User $user Who to give credit for the action
1380          * @param bool $ignoreWarnings Can be used for API interaction, default false
1381          * @param array $logEntryTags Change tags to apply to the entry
1382          * that will be created in the tag management log
1383          * @return Status If successful, the Status contains the ID of the added log
1384          * entry as its value
1385          * @since 1.25
1386          */
1387         public static function deleteTagWithChecks( $tag, $reason, User $user,
1388                 $ignoreWarnings = false, array $logEntryTags = []
1389         ) {
1390                 // are we allowed to do this?
1391                 $result = self::canDeleteTag( $tag, $user );
1392                 if ( $ignoreWarnings ? !$result->isOK() : !$result->isGood() ) {
1393                         $result->value = null;
1394                         return $result;
1395                 }
1396
1397                 // store the tag usage statistics
1398                 $tagUsage = self::tagUsageStatistics();
1399                 $hitcount = $tagUsage[$tag] ?? 0;
1400
1401                 // do it!
1402                 $deleteResult = self::deleteTagEverywhere( $tag );
1403                 if ( !$deleteResult->isOK() ) {
1404                         return $deleteResult;
1405                 }
1406
1407                 // log it
1408                 $logId = self::logTagManagementAction( 'delete', $tag, $reason, $user,
1409                         $hitcount, $logEntryTags );
1410
1411                 $deleteResult->value = $logId;
1412                 return $deleteResult;
1413         }
1414
1415         /**
1416          * Lists those tags which core or extensions report as being "active".
1417          *
1418          * @return array
1419          * @since 1.25
1420          */
1421         public static function listSoftwareActivatedTags() {
1422                 // core active tags
1423                 $tags = self::getSoftwareTags();
1424                 if ( !Hooks::isRegistered( 'ChangeTagsListActive' ) ) {
1425                         return $tags;
1426                 }
1427                 $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
1428                 return $cache->getWithSetCallback(
1429                         $cache->makeKey( 'active-tags' ),
1430                         WANObjectCache::TTL_MINUTE * 5,
1431                         function ( $oldValue, &$ttl, array &$setOpts ) use ( $tags ) {
1432                                 $setOpts += Database::getCacheSetOptions( wfGetDB( DB_REPLICA ) );
1433
1434                                 // Ask extensions which tags they consider active
1435                                 Hooks::run( 'ChangeTagsListActive', [ &$tags ] );
1436                                 return $tags;
1437                         },
1438                         [
1439                                 'checkKeys' => [ $cache->makeKey( 'active-tags' ) ],
1440                                 'lockTSE' => WANObjectCache::TTL_MINUTE * 5,
1441                                 'pcTTL' => WANObjectCache::TTL_PROC_LONG
1442                         ]
1443                 );
1444         }
1445
1446         /**
1447          * Basically lists defined tags which count even if they aren't applied to anything.
1448          * It returns a union of the results of listExplicitlyDefinedTags()
1449          *
1450          * @return string[] Array of strings: tags
1451          */
1452         public static function listDefinedTags() {
1453                 $tags1 = self::listExplicitlyDefinedTags();
1454                 $tags2 = self::listSoftwareDefinedTags();
1455                 return array_values( array_unique( array_merge( $tags1, $tags2 ) ) );
1456         }
1457
1458         /**
1459          * Lists tags explicitly defined in the `valid_tag` table of the database.
1460          * Tags in table 'change_tag' which are not in table 'valid_tag' are not
1461          * included.
1462          *
1463          * Tries memcached first.
1464          *
1465          * @return string[] Array of strings: tags
1466          * @since 1.25
1467          */
1468         public static function listExplicitlyDefinedTags() {
1469                 $fname = __METHOD__;
1470
1471                 $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
1472                 return $cache->getWithSetCallback(
1473                         $cache->makeKey( 'valid-tags-db' ),
1474                         WANObjectCache::TTL_MINUTE * 5,
1475                         function ( $oldValue, &$ttl, array &$setOpts ) use ( $fname ) {
1476                                 $dbr = wfGetDB( DB_REPLICA );
1477
1478                                 $setOpts += Database::getCacheSetOptions( $dbr );
1479
1480                                 $tags = $dbr->selectFieldValues( 'valid_tag', 'vt_tag', [], $fname );
1481
1482                                 return array_filter( array_unique( $tags ) );
1483                         },
1484                         [
1485                                 'checkKeys' => [ $cache->makeKey( 'valid-tags-db' ) ],
1486                                 'lockTSE' => WANObjectCache::TTL_MINUTE * 5,
1487                                 'pcTTL' => WANObjectCache::TTL_PROC_LONG
1488                         ]
1489                 );
1490         }
1491
1492         /**
1493          * Lists tags defined by core or extensions using the ListDefinedTags hook.
1494          * Extensions need only define those tags they deem to be in active use.
1495          *
1496          * Tries memcached first.
1497          *
1498          * @return string[] Array of strings: tags
1499          * @since 1.25
1500          */
1501         public static function listSoftwareDefinedTags() {
1502                 // core defined tags
1503                 $tags = self::getSoftwareTags( true );
1504                 if ( !Hooks::isRegistered( 'ListDefinedTags' ) ) {
1505                         return $tags;
1506                 }
1507                 $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
1508                 return $cache->getWithSetCallback(
1509                         $cache->makeKey( 'valid-tags-hook' ),
1510                         WANObjectCache::TTL_MINUTE * 5,
1511                         function ( $oldValue, &$ttl, array &$setOpts ) use ( $tags ) {
1512                                 $setOpts += Database::getCacheSetOptions( wfGetDB( DB_REPLICA ) );
1513
1514                                 Hooks::run( 'ListDefinedTags', [ &$tags ] );
1515                                 return array_filter( array_unique( $tags ) );
1516                         },
1517                         [
1518                                 'checkKeys' => [ $cache->makeKey( 'valid-tags-hook' ) ],
1519                                 'lockTSE' => WANObjectCache::TTL_MINUTE * 5,
1520                                 'pcTTL' => WANObjectCache::TTL_PROC_LONG
1521                         ]
1522                 );
1523         }
1524
1525         /**
1526          * Invalidates the short-term cache of defined tags used by the
1527          * list*DefinedTags functions, as well as the tag statistics cache.
1528          * @since 1.25
1529          */
1530         public static function purgeTagCacheAll() {
1531                 $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
1532
1533                 $cache->touchCheckKey( $cache->makeKey( 'active-tags' ) );
1534                 $cache->touchCheckKey( $cache->makeKey( 'valid-tags-db' ) );
1535                 $cache->touchCheckKey( $cache->makeKey( 'valid-tags-hook' ) );
1536
1537                 self::purgeTagUsageCache();
1538         }
1539
1540         /**
1541          * Invalidates the tag statistics cache only.
1542          * @since 1.25
1543          */
1544         public static function purgeTagUsageCache() {
1545                 $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
1546
1547                 $cache->touchCheckKey( $cache->makeKey( 'change-tag-statistics' ) );
1548         }
1549
1550         /**
1551          * Returns a map of any tags used on the wiki to number of edits
1552          * tagged with them, ordered descending by the hitcount.
1553          * This does not include tags defined somewhere that have never been applied.
1554          *
1555          * Keeps a short-term cache in memory, so calling this multiple times in the
1556          * same request should be fine.
1557          *
1558          * @return array Array of string => int
1559          */
1560         public static function tagUsageStatistics() {
1561                 global $wgChangeTagsSchemaMigrationStage, $wgTagStatisticsNewTable;
1562                 if ( $wgChangeTagsSchemaMigrationStage > MIGRATION_WRITE_BOTH ||
1563                         ( $wgTagStatisticsNewTable && $wgChangeTagsSchemaMigrationStage > MIGRATION_OLD )
1564                 ) {
1565                         return self::newTagUsageStatistics();
1566                 }
1567
1568                 $fname = __METHOD__;
1569                 $cache = MediaWikiServices::getInstance()->getMainWANObjectCache();
1570                 return $cache->getWithSetCallback(
1571                         $cache->makeKey( 'change-tag-statistics' ),
1572                         WANObjectCache::TTL_MINUTE * 5,
1573                         function ( $oldValue, &$ttl, array &$setOpts ) use ( $fname ) {
1574                                 $dbr = wfGetDB( DB_REPLICA, 'vslow' );
1575
1576                                 $setOpts += Database::getCacheSetOptions( $dbr );
1577
1578                                 $res = $dbr->select(
1579                                         'change_tag',
1580                                         [ 'ct_tag', 'hitcount' => 'count(*)' ],
1581                                         [],
1582                                         $fname,
1583                                         [ 'GROUP BY' => 'ct_tag', 'ORDER BY' => 'hitcount DESC' ]
1584                                 );
1585
1586                                 $out = [];
1587                                 foreach ( $res as $row ) {
1588                                         $out[$row->ct_tag] = $row->hitcount;
1589                                 }
1590
1591                                 return $out;
1592                         },
1593                         [
1594                                 'checkKeys' => [ $cache->makeKey( 'change-tag-statistics' ) ],
1595                                 'lockTSE' => WANObjectCache::TTL_MINUTE * 5,
1596                                 'pcTTL' => WANObjectCache::TTL_PROC_LONG
1597                         ]
1598                 );
1599         }
1600
1601         /**
1602          * Same self::tagUsageStatistics() but uses change_tag_def.
1603          *
1604          * @return array Array of string => int
1605          */
1606         private static function newTagUsageStatistics() {
1607                 $dbr = wfGetDB( DB_REPLICA );
1608                 $res = $dbr->select(
1609                         'change_tag_def',
1610                         [ 'ctd_name', 'ctd_count' ],
1611                         [],
1612                         __METHOD__,
1613                         [ 'ORDER BY' => 'ctd_count DESC' ]
1614                 );
1615
1616                 $out = [];
1617                 foreach ( $res as $row ) {
1618                         $out[$row->ctd_name] = $row->ctd_count;
1619                 }
1620
1621                 return $out;
1622         }
1623
1624         /**
1625          * Indicate whether change tag editing UI is relevant
1626          *
1627          * Returns true if the user has the necessary right and there are any
1628          * editable tags defined.
1629          *
1630          * This intentionally doesn't check "any addable || any deletable", because
1631          * it seems like it would be more confusing than useful if the checkboxes
1632          * suddenly showed up because some abuse filter stopped defining a tag and
1633          * then suddenly disappeared when someone deleted all uses of that tag.
1634          *
1635          * @param User $user
1636          * @return bool
1637          */
1638         public static function showTagEditingUI( User $user ) {
1639                 return $user->isAllowed( 'changetags' ) && (bool)self::listExplicitlyDefinedTags();
1640         }
1641 }