includes/CommentStore.php

   1 <?php
   2 /**
   3  * Manage storage of comments in the database
   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  */
  22
  23 use MediaWiki\MediaWikiServices;
  24 use Wikimedia\Rdbms\IDatabase;
  25
  26 /**
  27  * CommentStore handles storage of comments (edit summaries, log reasons, etc)
  28  * in the database.
  29  * @since 1.30
  30  */
  31 class CommentStore {
  32
  33         /**
  34          * Maximum length of a comment in UTF-8 characters. Longer comments will be truncated.
  35          * @note This must be at least 255 and not greater than floor( MAX_COMMENT_LENGTH / 4 ).
  36          */
  37         const COMMENT_CHARACTER_LIMIT = 500;
  38
  39         /**
  40          * Maximum length of a comment in bytes. Longer comments will be truncated.
  41          * @note This value is determined by the size of the underlying database field,
  42          *  currently BLOB in MySQL/MariaDB.
  43          */
  44         const MAX_COMMENT_LENGTH = 65535;
  45
  46         /**
  47          * Maximum length of serialized data in bytes. Longer data will result in an exception.
  48          * @note This value is determined by the size of the underlying database field,
  49          *  currently BLOB in MySQL/MariaDB.
  50          */
  51         const MAX_DATA_LENGTH = 65535;
  52
  53         /**
  54          * Define fields that use temporary tables for transitional purposes
  55          * @var array Keys are '$key', values are arrays with these possible fields:
  56          *  - table: Temporary table name
  57          *  - pk: Temporary table column referring to the main table's primary key
  58          *  - field: Temporary table column referring comment.comment_id
  59          *  - joinPK: Main table's primary key
  60          *  - stage: Migration stage
  61          *  - deprecatedIn: Version when using insertWithTempTable() was deprecated
  62          */
  63         protected $tempTables = [
  64                 'rev_comment' => [
  65                         'table' => 'revision_comment_temp',
  66                         'pk' => 'revcomment_rev',
  67                         'field' => 'revcomment_comment_id',
  68                         'joinPK' => 'rev_id',
  69                         'stage' => MIGRATION_OLD,
  70                         'deprecatedIn' => null,
  71                 ],
  72                 'img_description' => [
  73                         'stage' => MIGRATION_NEW,
  74                         'deprecatedIn' => '1.32',
  75                 ],
  76         ];
  77
  78         /**
  79          * @since 1.30
  80          * @deprecated in 1.31
  81          * @var string|null
  82          */
  83         protected $key = null;
  84
  85         /**
  86          * @var int One of the MIGRATION_* constants
  87          * @todo Deprecate and remove once extensions seem unlikely to need to use
  88          *  it for migration anymore.
  89          */
  90         protected $stage;
  91
  92         /** @var array[] Cache for `self::getJoin()` */
  93         protected $joinCache = [];
  94
  95         /** @var Language Language to use for comment truncation */
  96         protected $lang;
  97
  98         /**
  99          * @param Language $lang Language to use for comment truncation. Defaults
 100          *  to content language.
 101          * @param int $migrationStage One of the MIGRATION_* constants. Always
 102          *  MIGRATION_NEW for MediaWiki core since 1.33.
 103          */
 104         public function __construct( Language $lang, $migrationStage ) {
 105                 $this->stage = $migrationStage;
 106                 $this->lang = $lang;
 107         }
 108
 109         /**
 110          * Static constructor for easier chaining
 111          * @deprecated in 1.31 Should not be constructed with a $key, use CommentStore::getStore
 112          * @param string $key A key such as "rev_comment" identifying the comment
 113          *  field being fetched.
 114          * @return CommentStore
 115          */
 116         public static function newKey( $key ) {
 117                 wfDeprecated( __METHOD__, '1.31' );
 118                 $store = new CommentStore(
 119                         MediaWikiServices::getInstance()->getContentLanguage(), MIGRATION_NEW
 120                 );
 121                 $store->key = $key;
 122                 return $store;
 123         }
 124
 125         /**
 126          * @since 1.31
 127          * @deprecated in 1.31 Use DI to inject a CommentStore instance into your class.
 128          * @return CommentStore
 129          */
 130         public static function getStore() {
 131                 return MediaWikiServices::getInstance()->getCommentStore();
 132         }
 133
 134         /**
 135          * Compat method allowing use of self::newKey until removed.
 136          * @param string|null $methodKey
 137          * @throws InvalidArgumentException
 138          * @return string
 139          */
 140         private function getKey( $methodKey = null ) {
 141                 $key = $this->key ?? $methodKey;
 142                 if ( $key === null ) {
 143                         // @codeCoverageIgnoreStart
 144                         throw new InvalidArgumentException( '$key should not be null' );
 145                         // @codeCoverageIgnoreEnd
 146                 }
 147                 return $key;
 148         }
 149
 150         /**
 151          * Get SELECT fields for the comment key
 152          *
 153          * Each resulting row should be passed to `self::getCommentLegacy()` to get the
 154          * actual comment.
 155          *
 156          * @note Use of this method may require a subsequent database query to
 157          *  actually fetch the comment. If possible, use `self::getJoin()` instead.
 158          *
 159          * @since 1.30
 160          * @since 1.31 Method signature changed, $key parameter added (with deprecated back compat)
 161          * @param string|null $key A key such as "rev_comment" identifying the comment
 162          *  field being fetched.
 163          * @return string[] to include in the `$vars` to `IDatabase->select()`. All
 164          *  fields are aliased, so `+` is safe to use.
 165          */
 166         public function getFields( $key = null ) {
 167                 $key = $this->getKey( $key );
 168                 $fields = [];
 169                 if ( $this->stage === MIGRATION_OLD ) {
 170                         $fields["{$key}_text"] = $key;
 171                         $fields["{$key}_data"] = 'NULL';
 172                         $fields["{$key}_cid"] = 'NULL';
 173                 } else {
 174                         if ( $this->stage < MIGRATION_NEW ) {
 175                                 $fields["{$key}_old"] = $key;
 176                         }
 177
 178                         $tempTableStage = isset( $this->tempTables[$key] )
 179                                 ? $this->tempTables[$key]['stage'] : MIGRATION_NEW;
 180                         if ( $tempTableStage < MIGRATION_NEW ) {
 181                                 $fields["{$key}_pk"] = $this->tempTables[$key]['joinPK'];
 182                         }
 183                         if ( $tempTableStage > MIGRATION_OLD ) {
 184                                 $fields["{$key}_id"] = "{$key}_id";
 185                         }
 186                 }
 187                 return $fields;
 188         }
 189
 190         /**
 191          * Get SELECT fields and joins for the comment key
 192          *
 193          * Each resulting row should be passed to `self::getComment()` to get the
 194          * actual comment.
 195          *
 196          * @since 1.30
 197          * @since 1.31 Method signature changed, $key parameter added (with deprecated back compat)
 198          * @param string|null $key A key such as "rev_comment" identifying the comment
 199          *  field being fetched.
 200          * @return array With three keys:
 201          *   - tables: (string[]) to include in the `$table` to `IDatabase->select()`
 202          *   - fields: (string[]) to include in the `$vars` to `IDatabase->select()`
 203          *   - joins: (array) to include in the `$join_conds` to `IDatabase->select()`
 204          *  All tables, fields, and joins are aliased, so `+` is safe to use.
 205          */
 206         public function getJoin( $key = null ) {
 207                 $key = $this->getKey( $key );
 208                 if ( !array_key_exists( $key, $this->joinCache ) ) {
 209                         $tables = [];
 210                         $fields = [];
 211                         $joins = [];
 212
 213                         if ( $this->stage === MIGRATION_OLD ) {
 214                                 $fields["{$key}_text"] = $key;
 215                                 $fields["{$key}_data"] = 'NULL';
 216                                 $fields["{$key}_cid"] = 'NULL';
 217                         } else {
 218                                 $join = $this->stage === MIGRATION_NEW ? 'JOIN' : 'LEFT JOIN';
 219
 220                                 $tempTableStage = isset( $this->tempTables[$key] )
 221                                         ? $this->tempTables[$key]['stage'] : MIGRATION_NEW;
 222                                 if ( $tempTableStage < MIGRATION_NEW ) {
 223                                         $t = $this->tempTables[$key];
 224                                         $alias = "temp_$key";
 225                                         $tables[$alias] = $t['table'];
 226                                         $joins[$alias] = [ $join, "{$alias}.{$t['pk']} = {$t['joinPK']}" ];
 227                                         if ( $tempTableStage === MIGRATION_OLD ) {
 228                                                 $joinField = "{$alias}.{$t['field']}";
 229                                         } else {
 230                                                 // Nothing hits this code path for now, but will in the future when we set
 231                                                 // $this->tempTables['rev_comment']['stage'] to MIGRATION_WRITE_NEW while
 232                                                 // merging revision_comment_temp into revision.
 233                                                 // @codeCoverageIgnoreStart
 234                                                 $joins[$alias][0] = 'LEFT JOIN';
 235                                                 $joinField = "(CASE WHEN {$key}_id != 0 THEN {$key}_id ELSE {$alias}.{$t['field']} END)";
 236                                                 throw new LogicException( 'Nothing should reach this code path at this time' );
 237                                                 // @codeCoverageIgnoreEnd
 238                                         }
 239                                 } else {
 240                                         $joinField = "{$key}_id";
 241                                 }
 242
 243                                 $alias = "comment_$key";
 244                                 $tables[$alias] = 'comment';
 245                                 $joins[$alias] = [ $join, "{$alias}.comment_id = {$joinField}" ];
 246
 247                                 if ( $this->stage === MIGRATION_NEW ) {
 248                                         $fields["{$key}_text"] = "{$alias}.comment_text";
 249                                 } else {
 250                                         $fields["{$key}_text"] = "COALESCE( {$alias}.comment_text, $key )";
 251                                 }
 252                                 $fields["{$key}_data"] = "{$alias}.comment_data";
 253                                 $fields["{$key}_cid"] = "{$alias}.comment_id";
 254                         }
 255
 256                         $this->joinCache[$key] = [
 257                                 'tables' => $tables,
 258                                 'fields' => $fields,
 259                                 'joins' => $joins,
 260                         ];
 261                 }
 262
 263                 return $this->joinCache[$key];
 264         }
 265
 266         /**
 267          * Extract the comment from a row
 268          *
 269          * Shared implementation for getComment() and getCommentLegacy()
 270          *
 271          * @param IDatabase|null $db Database handle for getCommentLegacy(), or null for getComment()
 272          * @param string $key A key such as "rev_comment" identifying the comment
 273          *  field being fetched.
 274          * @param object|array $row
 275          * @param bool $fallback
 276          * @return CommentStoreComment
 277          */
 278         private function getCommentInternal( IDatabase $db = null, $key, $row, $fallback = false ) {
 279                 $row = (array)$row;
 280                 if ( array_key_exists( "{$key}_text", $row ) && array_key_exists( "{$key}_data", $row ) ) {
 281                         $cid = $row["{$key}_cid"] ?? null;
 282                         $text = $row["{$key}_text"];
 283                         $data = $row["{$key}_data"];
 284                 } elseif ( $this->stage === MIGRATION_OLD ) {
 285                         $cid = null;
 286                         if ( $fallback && isset( $row[$key] ) ) {
 287                                 wfLogWarning( "Using deprecated fallback handling for comment $key" );
 288                                 $text = $row[$key];
 289                         } else {
 290                                 wfLogWarning( "Missing {$key}_text and {$key}_data fields in row with MIGRATION_OLD" );
 291                                 $text = '';
 292                         }
 293                         $data = null;
 294                 } else {
 295                         $tempTableStage = isset( $this->tempTables[$key] )
 296                                 ? $this->tempTables[$key]['stage'] : MIGRATION_NEW;
 297                         $row2 = null;
 298                         if ( $tempTableStage > MIGRATION_OLD && array_key_exists( "{$key}_id", $row ) ) {
 299                                 if ( !$db ) {
 300                                         throw new InvalidArgumentException(
 301                                                 "\$row does not contain fields needed for comment $key and getComment(), but "
 302                                                 . "does have fields for getCommentLegacy()"
 303                                         );
 304                                 }
 305                                 $id = $row["{$key}_id"];
 306                                 $row2 = $db->selectRow(
 307                                         'comment',
 308                                         [ 'comment_id', 'comment_text', 'comment_data' ],
 309                                         [ 'comment_id' => $id ],
 310                                         __METHOD__
 311                                 );
 312                         }
 313                         if ( !$row2 && $tempTableStage < MIGRATION_NEW && array_key_exists( "{$key}_pk", $row ) ) {
 314                                 if ( !$db ) {
 315                                         throw new InvalidArgumentException(
 316                                                 "\$row does not contain fields needed for comment $key and getComment(), but "
 317                                                 . "does have fields for getCommentLegacy()"
 318                                         );
 319                                 }
 320                                 $t = $this->tempTables[$key];
 321                                 $id = $row["{$key}_pk"];
 322                                 $row2 = $db->selectRow(
 323                                         [ $t['table'], 'comment' ],
 324                                         [ 'comment_id', 'comment_text', 'comment_data' ],
 325                                         [ $t['pk'] => $id ],
 326                                         __METHOD__,
 327                                         [],
 328                                         [ 'comment' => [ 'JOIN', [ "comment_id = {$t['field']}" ] ] ]
 329                                 );
 330                         }
 331                         if ( $row2 === null && $fallback && isset( $row[$key] ) ) {
 332                                 wfLogWarning( "Using deprecated fallback handling for comment $key" );
 333                                 $row2 = (object)[ 'comment_text' => $row[$key], 'comment_data' => null ];
 334                         }
 335                         if ( $row2 === null ) {
 336                                 throw new InvalidArgumentException( "\$row does not contain fields needed for comment $key" );
 337                         }
 338
 339                         if ( $row2 ) {
 340                                 $cid = $row2->comment_id;
 341                                 $text = $row2->comment_text;
 342                                 $data = $row2->comment_data;
 343                         } elseif ( $this->stage < MIGRATION_NEW && array_key_exists( "{$key}_old", $row ) ) {
 344                                 $cid = null;
 345                                 $text = $row["{$key}_old"];
 346                                 $data = null;
 347                         } else {
 348                                 // @codeCoverageIgnoreStart
 349                                 wfLogWarning( "Missing comment row for $key, id=$id" );
 350                                 $cid = null;
 351                                 $text = '';
 352                                 $data = null;
 353                                 // @codeCoverageIgnoreEnd
 354                         }
 355                 }
 356
 357                 $msg = null;
 358                 if ( $data !== null ) {
 359                         $data = FormatJson::decode( $data, true );
 360                         if ( !is_array( $data ) ) {
 361                                 // @codeCoverageIgnoreStart
 362                                 wfLogWarning( "Invalid JSON object in comment: $data" );
 363                                 $data = null;
 364                                 // @codeCoverageIgnoreEnd
 365                         } else {
 366                                 if ( isset( $data['_message'] ) ) {
 367                                         $msg = self::decodeMessage( $data['_message'] )
 368                                                 ->setInterfaceMessageFlag( true );
 369                                 }
 370                                 if ( !empty( $data['_null'] ) ) {
 371                                         $data = null;
 372                                 } else {
 373                                         foreach ( $data as $k => $v ) {
 374                                                 if ( substr( $k, 0, 1 ) === '_' ) {
 375                                                         unset( $data[$k] );
 376                                                 }
 377                                         }
 378                                 }
 379                         }
 380                 }
 381
 382                 return new CommentStoreComment( $cid, $text, $msg, $data );
 383         }
 384
 385         /**
 386          * Extract the comment from a row
 387          *
 388          * Use `self::getJoin()` to ensure the row contains the needed data.
 389          *
 390          * If you need to fake a comment in a row for some reason, set fields
 391          * `{$key}_text` (string) and `{$key}_data` (JSON string or null).
 392          *
 393          * @since 1.30
 394          * @since 1.31 Method signature changed, $key parameter added (with deprecated back compat)
 395          * @param string $key A key such as "rev_comment" identifying the comment
 396          *  field being fetched.
 397          * @param object|array|null $row Result row.
 398          * @param bool $fallback If true, fall back as well as possible instead of throwing an exception.
 399          * @return CommentStoreComment
 400          */
 401         public function getComment( $key, $row = null, $fallback = false ) {
 402                 // Compat for method sig change in 1.31 (introduction of $key)
 403                 if ( $this->key !== null ) {
 404                         $fallback = $row;
 405                         $row = $key;
 406                         $key = $this->getKey();
 407                 }
 408                 if ( $row === null ) {
 409                         // @codeCoverageIgnoreStart
 410                         throw new InvalidArgumentException( '$row must not be null' );
 411                         // @codeCoverageIgnoreEnd
 412                 }
 413                 return $this->getCommentInternal( null, $key, $row, $fallback );
 414         }
 415
 416         /**
 417          * Extract the comment from a row, with legacy lookups.
 418          *
 419          * If `$row` might have been generated using `self::getFields()` rather
 420          * than `self::getJoin()`, use this. Prefer `self::getComment()` if you
 421          * know callers used `self::getJoin()` for the row fetch.
 422          *
 423          * If you need to fake a comment in a row for some reason, set fields
 424          * `{$key}_text` (string) and `{$key}_data` (JSON string or null).
 425          *
 426          * @since 1.30
 427          * @since 1.31 Method signature changed, $key parameter added (with deprecated back compat)
 428          * @param IDatabase $db Database handle to use for lookup
 429          * @param string $key A key such as "rev_comment" identifying the comment
 430          *  field being fetched.
 431          * @param object|array|null $row Result row.
 432          * @param bool $fallback If true, fall back as well as possible instead of throwing an exception.
 433          * @return CommentStoreComment
 434          */
 435         public function getCommentLegacy( IDatabase $db, $key, $row = null, $fallback = false ) {
 436                 // Compat for method sig change in 1.31 (introduction of $key)
 437                 if ( $this->key !== null ) {
 438                         $fallback = $row;
 439                         $row = $key;
 440                         $key = $this->getKey();
 441                 }
 442                 if ( $row === null ) {
 443                         // @codeCoverageIgnoreStart
 444                         throw new InvalidArgumentException( '$row must not be null' );
 445                         // @codeCoverageIgnoreEnd
 446                 }
 447                 return $this->getCommentInternal( $db, $key, $row, $fallback );
 448         }
 449
 450         /**
 451          * Create a new CommentStoreComment, inserting it into the database if necessary
 452          *
 453          * If a comment is going to be passed to `self::insert()` or the like
 454          * multiple times, it will be more efficient to pass a CommentStoreComment
 455          * once rather than making `self::insert()` do it every time through.
 456          *
 457          * @note When passing a CommentStoreComment, this may set `$comment->id` if
 458          *  it's not already set. If `$comment->id` is already set, it will not be
 459          *  verified that the specified comment actually exists or that it
 460          *  corresponds to the comment text, message, and/or data in the
 461          *  CommentStoreComment.
 462          * @param IDatabase $dbw Database handle to insert on. Unused if `$comment`
 463          *  is a CommentStoreComment and `$comment->id` is set.
 464          * @param string|Message|CommentStoreComment $comment Comment text or Message object, or
 465          *  a CommentStoreComment.
 466          * @param array|null $data Structured data to store. Keys beginning with '_' are reserved.
 467          *  Ignored if $comment is a CommentStoreComment.
 468          * @return CommentStoreComment
 469          */
 470         public function createComment( IDatabase $dbw, $comment, array $data = null ) {
 471                 $comment = CommentStoreComment::newUnsavedComment( $comment, $data );
 472
 473                 # Truncate comment in a Unicode-sensitive manner
 474                 $comment->text = $this->lang->truncateForVisual( $comment->text, self::COMMENT_CHARACTER_LIMIT );
 475
 476                 if ( $this->stage > MIGRATION_OLD && !$comment->id ) {
 477                         $dbData = $comment->data;
 478                         if ( !$comment->message instanceof RawMessage ) {
 479                                 if ( $dbData === null ) {
 480                                         $dbData = [ '_null' => true ];
 481                                 }
 482                                 $dbData['_message'] = self::encodeMessage( $comment->message );
 483                         }
 484                         if ( $dbData !== null ) {
 485                                 $dbData = FormatJson::encode( (object)$dbData, false, FormatJson::ALL_OK );
 486                                 $len = strlen( $dbData );
 487                                 if ( $len > self::MAX_DATA_LENGTH ) {
 488                                         $max = self::MAX_DATA_LENGTH;
 489                                         throw new OverflowException( "Comment data is too long ($len bytes, maximum is $max)" );
 490                                 }
 491                         }
 492
 493                         $hash = self::hash( $comment->text, $dbData );
 494                         $comment->id = $dbw->selectField(
 495                                 'comment',
 496                                 'comment_id',
 497                                 [
 498                                         'comment_hash' => $hash,
 499                                         'comment_text' => $comment->text,
 500                                         'comment_data' => $dbData,
 501                                 ],
 502                                 __METHOD__
 503                         );
 504                         if ( !$comment->id ) {
 505                                 $dbw->insert(
 506                                         'comment',
 507                                         [
 508                                                 'comment_hash' => $hash,
 509                                                 'comment_text' => $comment->text,
 510                                                 'comment_data' => $dbData,
 511                                         ],
 512                                         __METHOD__
 513                                 );
 514                                 $comment->id = $dbw->insertId();
 515                         }
 516                 }
 517
 518                 return $comment;
 519         }
 520
 521         /**
 522          * Implementation for `self::insert()` and `self::insertWithTempTable()`
 523          * @param IDatabase $dbw
 524          * @param string $key A key such as "rev_comment" identifying the comment
 525          *  field being fetched.
 526          * @param string|Message|CommentStoreComment $comment
 527          * @param array|null $data
 528          * @return array [ array $fields, callable $callback ]
 529          */
 530         private function insertInternal( IDatabase $dbw, $key, $comment, $data ) {
 531                 $fields = [];
 532                 $callback = null;
 533
 534                 $comment = $this->createComment( $dbw, $comment, $data );
 535
 536                 if ( $this->stage <= MIGRATION_WRITE_BOTH ) {
 537                         $fields[$key] = $this->lang->truncateForDatabase( $comment->text, 255 );
 538                 }
 539
 540                 if ( $this->stage >= MIGRATION_WRITE_BOTH ) {
 541                         $tempTableStage = isset( $this->tempTables[$key] )
 542                                 ? $this->tempTables[$key]['stage'] : MIGRATION_NEW;
 543                         if ( $tempTableStage <= MIGRATION_WRITE_BOTH ) {
 544                                 $t = $this->tempTables[$key];
 545                                 $func = __METHOD__;
 546                                 $commentId = $comment->id;
 547                                 $callback = function ( $id ) use ( $dbw, $commentId, $t, $func ) {
 548                                         $dbw->insert(
 549                                                 $t['table'],
 550                                                 [
 551                                                         $t['pk'] => $id,
 552                                                         $t['field'] => $commentId,
 553                                                 ],
 554                                                 $func
 555                                         );
 556                                 };
 557                         }
 558                         if ( $tempTableStage >= MIGRATION_WRITE_BOTH ) {
 559                                 $fields["{$key}_id"] = $comment->id;
 560                         }
 561                 }
 562
 563                 return [ $fields, $callback ];
 564         }
 565
 566         /**
 567          * Insert a comment in preparation for a row that references it
 568          *
 569          * @note It's recommended to include both the call to this method and the
 570          *  row insert in the same transaction.
 571          *
 572          * @since 1.30
 573          * @since 1.31 Method signature changed, $key parameter added (with deprecated back compat)
 574          * @param IDatabase $dbw Database handle to insert on
 575          * @param string $key A key such as "rev_comment" identifying the comment
 576          *  field being fetched.
 577          * @param string|Message|CommentStoreComment|null $comment As for `self::createComment()`
 578          * @param array|null $data As for `self::createComment()`
 579          * @return array Fields for the insert or update
 580          */
 581         public function insert( IDatabase $dbw, $key, $comment = null, $data = null ) {
 582                 // Compat for method sig change in 1.31 (introduction of $key)
 583                 if ( $this->key !== null ) {
 584                         $data = $comment;
 585                         $comment = $key;
 586                         $key = $this->key;
 587                 }
 588                 if ( $comment === null ) {
 589                         // @codeCoverageIgnoreStart
 590                         throw new InvalidArgumentException( '$comment can not be null' );
 591                         // @codeCoverageIgnoreEnd
 592                 }
 593
 594                 $tempTableStage = isset( $this->tempTables[$key] )
 595                         ? $this->tempTables[$key]['stage'] : MIGRATION_NEW;
 596                 if ( $tempTableStage < MIGRATION_WRITE_NEW ) {
 597                         throw new InvalidArgumentException( "Must use insertWithTempTable() for $key" );
 598                 }
 599
 600                 list( $fields ) = $this->insertInternal( $dbw, $key, $comment, $data );
 601                 return $fields;
 602         }
 603
 604         /**
 605          * Insert a comment in a temporary table in preparation for a row that references it
 606          *
 607          * This is currently needed for "rev_comment" and "img_description". In the
 608          * future that requirement will be removed.
 609          *
 610          * @note It's recommended to include both the call to this method and the
 611          *  row insert in the same transaction.
 612          *
 613          * @since 1.30
 614          * @since 1.31 Method signature changed, $key parameter added (with deprecated back compat)
 615          * @param IDatabase $dbw Database handle to insert on
 616          * @param string $key A key such as "rev_comment" identifying the comment
 617          *  field being fetched.
 618          * @param string|Message|CommentStoreComment|null $comment As for `self::createComment()`
 619          * @param array|null $data As for `self::createComment()`
 620          * @return array Two values:
 621          *  - array Fields for the insert or update
 622          *  - callable Function to call when the primary key of the row being
 623          *    inserted/updated is known. Pass it that primary key.
 624          */
 625         public function insertWithTempTable( IDatabase $dbw, $key, $comment = null, $data = null ) {
 626                 // Compat for method sig change in 1.31 (introduction of $key)
 627                 if ( $this->key !== null ) {
 628                         $data = $comment;
 629                         $comment = $key;
 630                         $key = $this->getKey();
 631                 }
 632                 if ( $comment === null ) {
 633                         // @codeCoverageIgnoreStart
 634                         throw new InvalidArgumentException( '$comment can not be null' );
 635                         // @codeCoverageIgnoreEnd
 636                 }
 637
 638                 if ( !isset( $this->tempTables[$key] ) ) {
 639                         throw new InvalidArgumentException( "Must use insert() for $key" );
 640                 } elseif ( isset( $this->tempTables[$key]['deprecatedIn'] ) ) {
 641                         wfDeprecated( __METHOD__ . " for $key", $this->tempTables[$key]['deprecatedIn'] );
 642                 }
 643
 644                 list( $fields, $callback ) = $this->insertInternal( $dbw, $key, $comment, $data );
 645                 if ( !$callback ) {
 646                         $callback = function () {
 647                                 // Do nothing.
 648                         };
 649                 }
 650                 return [ $fields, $callback ];
 651         }
 652
 653         /**
 654          * Encode a Message as a PHP data structure
 655          * @param Message $msg
 656          * @return array
 657          */
 658         protected static function encodeMessage( Message $msg ) {
 659                 $key = count( $msg->getKeysToTry() ) > 1 ? $msg->getKeysToTry() : $msg->getKey();
 660                 $params = $msg->getParams();
 661                 foreach ( $params as &$param ) {
 662                         if ( $param instanceof Message ) {
 663                                 $param = [
 664                                         'message' => self::encodeMessage( $param )
 665                                 ];
 666                         }
 667                 }
 668                 array_unshift( $params, $key );
 669                 return $params;
 670         }
 671
 672         /**
 673          * Decode a message that was encoded by self::encodeMessage()
 674          * @param array $data
 675          * @return Message
 676          */
 677         protected static function decodeMessage( $data ) {
 678                 $key = array_shift( $data );
 679                 foreach ( $data as &$param ) {
 680                         if ( is_object( $param ) ) {
 681                                 $param = (array)$param;
 682                         }
 683                         if ( is_array( $param ) && count( $param ) === 1 && isset( $param['message'] ) ) {
 684                                 $param = self::decodeMessage( $param['message'] );
 685                         }
 686                 }
 687                 return new Message( $key, $data );
 688         }
 689
 690         /**
 691          * Hashing function for comment storage
 692          * @param string $text Comment text
 693          * @param string|null $data Comment data
 694          * @return int 32-bit signed integer
 695          */
 696         public static function hash( $text, $data ) {
 697                 $hash = crc32( $text ) ^ crc32( (string)$data );
 698
 699                 // 64-bit PHP returns an unsigned CRC, change it to signed for
 700                 // insertion into the database.
 701                 if ( $hash >= 0x80000000 ) {
 702                         $hash |= -1 << 32;
 703                 }
 704
 705                 return $hash;
 706         }
 707
 708 }