includes/db/Database.php

   1 <?php
   2
   3 /**
   4  * @defgroup Database Database
   5  *
   6  * This file deals with database interface functions
   7  * and query specifics/optimisations.
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License as published by
  11  * the Free Software Foundation; either version 2 of the License, or
  12  * (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License along
  20  * with this program; if not, write to the Free Software Foundation, Inc.,
  21  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  22  * http://www.gnu.org/copyleft/gpl.html
  23  *
  24  * @file
  25  * @ingroup Database
  26  */
  27
  28 /**
  29  * Database abstraction object
  30  * @ingroup Database
  31  */
  32 abstract class DatabaseBase implements IDatabase {
  33         /** Number of times to re-try an operation in case of deadlock */
  34         const DEADLOCK_TRIES = 4;
  35         /** Minimum time to wait before retry, in microseconds */
  36         const DEADLOCK_DELAY_MIN = 500000;
  37         /** Maximum time to wait before retry */
  38         const DEADLOCK_DELAY_MAX = 1500000;
  39
  40         /** How long before it is worth doing a dummy query to test the connection */
  41         const PING_TTL = 1.0;
  42         const PING_QUERY = 'SELECT 1 AS ping';
  43
  44         const TINY_WRITE_SEC = .010;
  45         const SLOW_WRITE_SEC = .500;
  46         const SMALL_WRITE_ROWS = 100;
  47
  48         /** @var string SQL query */
  49         protected $mLastQuery = '';
  50         /** @var bool */
  51         protected $mDoneWrites = false;
  52         /** @var string|bool */
  53         protected $mPHPError = false;
  54         /** @var string */
  55         protected $mServer;
  56         /** @var string */
  57         protected $mUser;
  58         /** @var string */
  59         protected $mPassword;
  60         /** @var string */
  61         protected $mDBname;
  62         /** @var bool */
  63         protected $cliMode;
  64
  65         /** @var BagOStuff APC cache */
  66         protected $srvCache;
  67
  68         /** @var resource Database connection */
  69         protected $mConn = null;
  70         /** @var bool */
  71         protected $mOpened = false;
  72
  73         /** @var array[] List of (callable, method name) */
  74         protected $mTrxIdleCallbacks = [];
  75         /** @var array[] List of (callable, method name) */
  76         protected $mTrxPreCommitCallbacks = [];
  77         /** @var array[] List of (callable, method name) */
  78         protected $mTrxEndCallbacks = [];
  79         /** @var array[] Map of (name => (callable, method name)) */
  80         protected $mTrxRecurringCallbacks = [];
  81         /** @var bool Whether to suppress triggering of transaction end callbacks */
  82         protected $mTrxEndCallbacksSuppressed = false;
  83
  84         /** @var string */
  85         protected $mTablePrefix;
  86         /** @var string */
  87         protected $mSchema;
  88         /** @var integer */
  89         protected $mFlags;
  90         /** @var bool */
  91         protected $mForeign;
  92         /** @var array */
  93         protected $mLBInfo = [];
  94         /** @var bool|null */
  95         protected $mDefaultBigSelects = null;
  96         /** @var array|bool */
  97         protected $mSchemaVars = false;
  98         /** @var array */
  99         protected $mSessionVars = [];
 100         /** @var array|null */
 101         protected $preparedArgs;
 102         /** @var string|bool|null Stashed value of html_errors INI setting */
 103         protected $htmlErrors;
 104         /** @var string */
 105         protected $delimiter = ';';
 106
 107         /**
 108          * Either 1 if a transaction is active or 0 otherwise.
 109          * The other Trx fields may not be meaningfull if this is 0.
 110          *
 111          * @var int
 112          */
 113         protected $mTrxLevel = 0;
 114         /**
 115          * Either a short hexidecimal string if a transaction is active or ""
 116          *
 117          * @var string
 118          * @see DatabaseBase::mTrxLevel
 119          */
 120         protected $mTrxShortId = '';
 121         /**
 122          * The UNIX time that the transaction started. Callers can assume that if
 123          * snapshot isolation is used, then the data is *at least* up to date to that
 124          * point (possibly more up-to-date since the first SELECT defines the snapshot).
 125          *
 126          * @var float|null
 127          * @see DatabaseBase::mTrxLevel
 128          */
 129         private $mTrxTimestamp = null;
 130         /** @var float Lag estimate at the time of BEGIN */
 131         private $mTrxSlaveLag = null;
 132         /**
 133          * Remembers the function name given for starting the most recent transaction via begin().
 134          * Used to provide additional context for error reporting.
 135          *
 136          * @var string
 137          * @see DatabaseBase::mTrxLevel
 138          */
 139         private $mTrxFname = null;
 140         /**
 141          * Record if possible write queries were done in the last transaction started
 142          *
 143          * @var bool
 144          * @see DatabaseBase::mTrxLevel
 145          */
 146         private $mTrxDoneWrites = false;
 147         /**
 148          * Record if the current transaction was started implicitly due to DBO_TRX being set.
 149          *
 150          * @var bool
 151          * @see DatabaseBase::mTrxLevel
 152          */
 153         private $mTrxAutomatic = false;
 154         /**
 155          * Array of levels of atomicity within transactions
 156          *
 157          * @var array
 158          */
 159         private $mTrxAtomicLevels = [];
 160         /**
 161          * Record if the current transaction was started implicitly by DatabaseBase::startAtomic
 162          *
 163          * @var bool
 164          */
 165         private $mTrxAutomaticAtomic = false;
 166         /**
 167          * Track the write query callers of the current transaction
 168          *
 169          * @var string[]
 170          */
 171         private $mTrxWriteCallers = [];
 172         /**
 173          * @var float Seconds spent in write queries for the current transaction
 174          */
 175         private $mTrxWriteDuration = 0.0;
 176         /**
 177          * @var integer Number of write queries for the current transaction
 178          */
 179         private $mTrxWriteQueryCount = 0;
 180         /**
 181          * @var float Like mTrxWriteQueryCount but excludes lock-bound, easy to replicate, queries
 182          */
 183         private $mTrxWriteAdjDuration = 0.0;
 184         /**
 185          * @var integer Number of write queries counted in mTrxWriteAdjDuration
 186          */
 187         private $mTrxWriteAdjQueryCount = 0;
 188         /**
 189          * @var float RTT time estimate
 190          */
 191         private $mRTTEstimate = 0.0;
 192
 193         /** @var array Map of (name => 1) for locks obtained via lock() */
 194         private $mNamedLocksHeld = [];
 195
 196         /** @var IDatabase|null Lazy handle to the master DB this server replicates from */
 197         private $lazyMasterHandle;
 198
 199         /**
 200          * @since 1.21
 201          * @var resource File handle for upgrade
 202          */
 203         protected $fileHandle = null;
 204
 205         /**
 206          * @since 1.22
 207          * @var string[] Process cache of VIEWs names in the database
 208          */
 209         protected $allViews = null;
 210
 211         /** @var float UNIX timestamp */
 212         protected $lastPing = 0.0;
 213
 214         /** @var int[] Prior mFlags values */
 215         private $priorFlags = [];
 216
 217         /** @var Profiler */
 218         protected $profiler;
 219         /** @var TransactionProfiler */
 220         protected $trxProfiler;
 221
 222         public function getServerInfo() {
 223                 return $this->getServerVersion();
 224         }
 225
 226         /**
 227          * @return string Command delimiter used by this database engine
 228          */
 229         public function getDelimiter() {
 230                 return $this->delimiter;
 231         }
 232
 233         /**
 234          * Boolean, controls output of large amounts of debug information.
 235          * @param bool|null $debug
 236          *   - true to enable debugging
 237          *   - false to disable debugging
 238          *   - omitted or null to do nothing
 239          *
 240          * @return bool|null Previous value of the flag
 241          */
 242         public function debug( $debug = null ) {
 243                 return wfSetBit( $this->mFlags, DBO_DEBUG, $debug );
 244         }
 245
 246         public function bufferResults( $buffer = null ) {
 247                 if ( is_null( $buffer ) ) {
 248                         return !(bool)( $this->mFlags & DBO_NOBUFFER );
 249                 } else {
 250                         return !wfSetBit( $this->mFlags, DBO_NOBUFFER, !$buffer );
 251                 }
 252         }
 253
 254         /**
 255          * Turns on (false) or off (true) the automatic generation and sending
 256          * of a "we're sorry, but there has been a database error" page on
 257          * database errors. Default is on (false). When turned off, the
 258          * code should use lastErrno() and lastError() to handle the
 259          * situation as appropriate.
 260          *
 261          * Do not use this function outside of the Database classes.
 262          *
 263          * @param null|bool $ignoreErrors
 264          * @return bool The previous value of the flag.
 265          */
 266         protected function ignoreErrors( $ignoreErrors = null ) {
 267                 return wfSetBit( $this->mFlags, DBO_IGNORE, $ignoreErrors );
 268         }
 269
 270         public function trxLevel() {
 271                 return $this->mTrxLevel;
 272         }
 273
 274         public function trxTimestamp() {
 275                 return $this->mTrxLevel ? $this->mTrxTimestamp : null;
 276         }
 277
 278         public function tablePrefix( $prefix = null ) {
 279                 return wfSetVar( $this->mTablePrefix, $prefix );
 280         }
 281
 282         public function dbSchema( $schema = null ) {
 283                 return wfSetVar( $this->mSchema, $schema );
 284         }
 285
 286         /**
 287          * Set the filehandle to copy write statements to.
 288          *
 289          * @param resource $fh File handle
 290          */
 291         public function setFileHandle( $fh ) {
 292                 $this->fileHandle = $fh;
 293         }
 294
 295         public function getLBInfo( $name = null ) {
 296                 if ( is_null( $name ) ) {
 297                         return $this->mLBInfo;
 298                 } else {
 299                         if ( array_key_exists( $name, $this->mLBInfo ) ) {
 300                                 return $this->mLBInfo[$name];
 301                         } else {
 302                                 return null;
 303                         }
 304                 }
 305         }
 306
 307         public function setLBInfo( $name, $value = null ) {
 308                 if ( is_null( $value ) ) {
 309                         $this->mLBInfo = $name;
 310                 } else {
 311                         $this->mLBInfo[$name] = $value;
 312                 }
 313         }
 314
 315         /**
 316          * Set a lazy-connecting DB handle to the master DB (for replication status purposes)
 317          *
 318          * @param IDatabase $conn
 319          * @since 1.27
 320          */
 321         public function setLazyMasterHandle( IDatabase $conn ) {
 322                 $this->lazyMasterHandle = $conn;
 323         }
 324
 325         /**
 326          * @return IDatabase|null
 327          * @see setLazyMasterHandle()
 328          * @since 1.27
 329          */
 330         public function getLazyMasterHandle() {
 331                 return $this->lazyMasterHandle;
 332         }
 333
 334         /**
 335          * @return TransactionProfiler
 336          */
 337         protected function getTransactionProfiler() {
 338                 return $this->trxProfiler;
 339         }
 340
 341         /**
 342          * @param TransactionProfiler $profiler
 343          * @since 1.27
 344          */
 345         public function setTransactionProfiler( TransactionProfiler $profiler ) {
 346                 $this->trxProfiler = $profiler;
 347         }
 348
 349         /**
 350          * Returns true if this database supports (and uses) cascading deletes
 351          *
 352          * @return bool
 353          */
 354         public function cascadingDeletes() {
 355                 return false;
 356         }
 357
 358         /**
 359          * Returns true if this database supports (and uses) triggers (e.g. on the page table)
 360          *
 361          * @return bool
 362          */
 363         public function cleanupTriggers() {
 364                 return false;
 365         }
 366
 367         /**
 368          * Returns true if this database is strict about what can be put into an IP field.
 369          * Specifically, it uses a NULL value instead of an empty string.
 370          *
 371          * @return bool
 372          */
 373         public function strictIPs() {
 374                 return false;
 375         }
 376
 377         /**
 378          * Returns true if this database uses timestamps rather than integers
 379          *
 380          * @return bool
 381          */
 382         public function realTimestamps() {
 383                 return false;
 384         }
 385
 386         public function implicitGroupby() {
 387                 return true;
 388         }
 389
 390         public function implicitOrderby() {
 391                 return true;
 392         }
 393
 394         /**
 395          * Returns true if this database can do a native search on IP columns
 396          * e.g. this works as expected: .. WHERE rc_ip = '127.42.12.102/32';
 397          *
 398          * @return bool
 399          */
 400         public function searchableIPs() {
 401                 return false;
 402         }
 403
 404         /**
 405          * Returns true if this database can use functional indexes
 406          *
 407          * @return bool
 408          */
 409         public function functionalIndexes() {
 410                 return false;
 411         }
 412
 413         public function lastQuery() {
 414                 return $this->mLastQuery;
 415         }
 416
 417         public function doneWrites() {
 418                 return (bool)$this->mDoneWrites;
 419         }
 420
 421         public function lastDoneWrites() {
 422                 return $this->mDoneWrites ?: false;
 423         }
 424
 425         public function writesPending() {
 426                 return $this->mTrxLevel && $this->mTrxDoneWrites;
 427         }
 428
 429         public function writesOrCallbacksPending() {
 430                 return $this->mTrxLevel && (
 431                         $this->mTrxDoneWrites || $this->mTrxIdleCallbacks || $this->mTrxPreCommitCallbacks
 432                 );
 433         }
 434
 435         public function pendingWriteQueryDuration( $type = self::ESTIMATE_TOTAL ) {
 436                 if ( !$this->mTrxLevel ) {
 437                         return false;
 438                 } elseif ( !$this->mTrxDoneWrites ) {
 439                         return 0.0;
 440                 }
 441
 442                 switch ( $type ) {
 443                         case self::ESTIMATE_DB_APPLY:
 444                                 $this->ping( $rtt );
 445                                 $rttAdjTotal = $this->mTrxWriteAdjQueryCount * $rtt;
 446                                 $applyTime = max( $this->mTrxWriteAdjDuration - $rttAdjTotal, 0 );
 447                                 // For omitted queries, make them count as something at least
 448                                 $omitted = $this->mTrxWriteQueryCount - $this->mTrxWriteAdjQueryCount;
 449                                 $applyTime += self::TINY_WRITE_SEC * $omitted;
 450
 451                                 return $applyTime;
 452                         default: // everything
 453                                 return $this->mTrxWriteDuration;
 454                 }
 455         }
 456
 457         public function pendingWriteCallers() {
 458                 return $this->mTrxLevel ? $this->mTrxWriteCallers : [];
 459         }
 460
 461         public function isOpen() {
 462                 return $this->mOpened;
 463         }
 464
 465         public function setFlag( $flag, $remember = self::REMEMBER_NOTHING ) {
 466                 if ( $remember === self::REMEMBER_PRIOR ) {
 467                         array_push( $this->priorFlags, $this->mFlags );
 468                 }
 469                 $this->mFlags |= $flag;
 470         }
 471
 472         public function clearFlag( $flag, $remember = self::REMEMBER_NOTHING ) {
 473                 if ( $remember === self::REMEMBER_PRIOR ) {
 474                         array_push( $this->priorFlags, $this->mFlags );
 475                 }
 476                 $this->mFlags &= ~$flag;
 477         }
 478
 479         public function restoreFlags( $state = self::RESTORE_PRIOR ) {
 480                 if ( !$this->priorFlags ) {
 481                         return;
 482                 }
 483
 484                 if ( $state === self::RESTORE_INITIAL ) {
 485                         $this->mFlags = reset( $this->priorFlags );
 486                         $this->priorFlags = [];
 487                 } else {
 488                         $this->mFlags = array_pop( $this->priorFlags );
 489                 }
 490         }
 491
 492         public function getFlag( $flag ) {
 493                 return !!( $this->mFlags & $flag );
 494         }
 495
 496         public function getProperty( $name ) {
 497                 return $this->$name;
 498         }
 499
 500         public function getWikiID() {
 501                 if ( $this->mTablePrefix ) {
 502                         return "{$this->mDBname}-{$this->mTablePrefix}";
 503                 } else {
 504                         return $this->mDBname;
 505                 }
 506         }
 507
 508         /**
 509          * Return a path to the DBMS-specific SQL file if it exists,
 510          * otherwise default SQL file
 511          *
 512          * @param string $filename
 513          * @return string
 514          */
 515         private function getSqlFilePath( $filename ) {
 516                 global $IP;
 517                 $dbmsSpecificFilePath = "$IP/maintenance/" . $this->getType() . "/$filename";
 518                 if ( file_exists( $dbmsSpecificFilePath ) ) {
 519                         return $dbmsSpecificFilePath;
 520                 } else {
 521                         return "$IP/maintenance/$filename";
 522                 }
 523         }
 524
 525         /**
 526          * Return a path to the DBMS-specific schema file,
 527          * otherwise default to tables.sql
 528          *
 529          * @return string
 530          */
 531         public function getSchemaPath() {
 532                 return $this->getSqlFilePath( 'tables.sql' );
 533         }
 534
 535         /**
 536          * Return a path to the DBMS-specific update key file,
 537          * otherwise default to update-keys.sql
 538          *
 539          * @return string
 540          */
 541         public function getUpdateKeysPath() {
 542                 return $this->getSqlFilePath( 'update-keys.sql' );
 543         }
 544
 545         /**
 546          * Get information about an index into an object
 547          * @param string $table Table name
 548          * @param string $index Index name
 549          * @param string $fname Calling function name
 550          * @return mixed Database-specific index description class or false if the index does not exist
 551          */
 552         abstract function indexInfo( $table, $index, $fname = __METHOD__ );
 553
 554         /**
 555          * Wrapper for addslashes()
 556          *
 557          * @param string $s String to be slashed.
 558          * @return string Slashed string.
 559          */
 560         abstract function strencode( $s );
 561
 562         /**
 563          * Constructor.
 564          *
 565          * FIXME: It is possible to construct a Database object with no associated
 566          * connection object, by specifying no parameters to __construct(). This
 567          * feature is deprecated and should be removed.
 568          *
 569          * DatabaseBase subclasses should not be constructed directly in external
 570          * code. DatabaseBase::factory() should be used instead.
 571          *
 572          * @param array $params Parameters passed from DatabaseBase::factory()
 573          */
 574         function __construct( array $params ) {
 575                 global $wgDBprefix, $wgDBmwschema;
 576
 577                 $this->srvCache = ObjectCache::getLocalServerInstance( 'hash' );
 578
 579                 $server = $params['host'];
 580                 $user = $params['user'];
 581                 $password = $params['password'];
 582                 $dbName = $params['dbname'];
 583                 $flags = $params['flags'];
 584                 $tablePrefix = $params['tablePrefix'];
 585                 $schema = $params['schema'];
 586                 $foreign = $params['foreign'];
 587
 588                 $this->cliMode = isset( $params['cliMode'] )
 589                         ? $params['cliMode']
 590                         : ( PHP_SAPI === 'cli' );
 591
 592                 $this->mFlags = $flags;
 593                 if ( $this->mFlags & DBO_DEFAULT ) {
 594                         if ( $this->cliMode ) {
 595                                 $this->mFlags &= ~DBO_TRX;
 596                         } else {
 597                                 $this->mFlags |= DBO_TRX;
 598                         }
 599                 }
 600
 601                 $this->mSessionVars = $params['variables'];
 602
 603                 /** Get the default table prefix*/
 604                 if ( $tablePrefix === 'get from global' ) {
 605                         $this->mTablePrefix = $wgDBprefix;
 606                 } else {
 607                         $this->mTablePrefix = $tablePrefix;
 608                 }
 609
 610                 /** Get the database schema*/
 611                 if ( $schema === 'get from global' ) {
 612                         $this->mSchema = $wgDBmwschema;
 613                 } else {
 614                         $this->mSchema = $schema;
 615                 }
 616
 617                 $this->mForeign = $foreign;
 618
 619                 $this->profiler = isset( $params['profiler'] )
 620                         ? $params['profiler']
 621                         : Profiler::instance(); // @TODO: remove global state
 622                 $this->trxProfiler = isset( $params['trxProfiler'] )
 623                         ? $params['trxProfiler']
 624                         : new TransactionProfiler();
 625
 626                 if ( $user ) {
 627                         $this->open( $server, $user, $password, $dbName );
 628                 }
 629
 630         }
 631
 632         /**
 633          * Called by serialize. Throw an exception when DB connection is serialized.
 634          * This causes problems on some database engines because the connection is
 635          * not restored on unserialize.
 636          */
 637         public function __sleep() {
 638                 throw new MWException( 'Database serialization may cause problems, since ' .
 639                         'the connection is not restored on wakeup.' );
 640         }
 641
 642         /**
 643          * Given a DB type, construct the name of the appropriate child class of
 644          * DatabaseBase. This is designed to replace all of the manual stuff like:
 645          *    $class = 'Database' . ucfirst( strtolower( $dbType ) );
 646          * as well as validate against the canonical list of DB types we have
 647          *
 648          * This factory function is mostly useful for when you need to connect to a
 649          * database other than the MediaWiki default (such as for external auth,
 650          * an extension, et cetera). Do not use this to connect to the MediaWiki
 651          * database. Example uses in core:
 652          * @see LoadBalancer::reallyOpenConnection()
 653          * @see ForeignDBRepo::getMasterDB()
 654          * @see WebInstallerDBConnect::execute()
 655          *
 656          * @since 1.18
 657          *
 658          * @param string $dbType A possible DB type
 659          * @param array $p An array of options to pass to the constructor.
 660          *    Valid options are: host, user, password, dbname, flags, tablePrefix, schema, driver
 661          * @throws MWException If the database driver or extension cannot be found
 662          * @return DatabaseBase|null DatabaseBase subclass or null
 663          */
 664         final public static function factory( $dbType, $p = [] ) {
 665                 global $wgCommandLineMode;
 666
 667                 $canonicalDBTypes = [
 668                         'mysql' => [ 'mysqli', 'mysql' ],
 669                         'postgres' => [],
 670                         'sqlite' => [],
 671                         'oracle' => [],
 672                         'mssql' => [],
 673                 ];
 674
 675                 $driver = false;
 676                 $dbType = strtolower( $dbType );
 677                 if ( isset( $canonicalDBTypes[$dbType] ) && $canonicalDBTypes[$dbType] ) {
 678                         $possibleDrivers = $canonicalDBTypes[$dbType];
 679                         if ( !empty( $p['driver'] ) ) {
 680                                 if ( in_array( $p['driver'], $possibleDrivers ) ) {
 681                                         $driver = $p['driver'];
 682                                 } else {
 683                                         throw new MWException( __METHOD__ .
 684                                                 " cannot construct Database with type '$dbType' and driver '{$p['driver']}'" );
 685                                 }
 686                         } else {
 687                                 foreach ( $possibleDrivers as $posDriver ) {
 688                                         if ( extension_loaded( $posDriver ) ) {
 689                                                 $driver = $posDriver;
 690                                                 break;
 691                                         }
 692                                 }
 693                         }
 694                 } else {
 695                         $driver = $dbType;
 696                 }
 697                 if ( $driver === false ) {
 698                         throw new MWException( __METHOD__ .
 699                                 " no viable database extension found for type '$dbType'" );
 700                 }
 701
 702                 // Determine schema defaults. Currently Microsoft SQL Server uses $wgDBmwschema,
 703                 // and everything else doesn't use a schema (e.g. null)
 704                 // Although postgres and oracle support schemas, we don't use them (yet)
 705                 // to maintain backwards compatibility
 706                 $defaultSchemas = [
 707                         'mssql' => 'get from global',
 708                 ];
 709
 710                 $class = 'Database' . ucfirst( $driver );
 711                 if ( class_exists( $class ) && is_subclass_of( $class, 'DatabaseBase' ) ) {
 712                         // Resolve some defaults for b/c
 713                         $p['host'] = isset( $p['host'] ) ? $p['host'] : false;
 714                         $p['user'] = isset( $p['user'] ) ? $p['user'] : false;
 715                         $p['password'] = isset( $p['password'] ) ? $p['password'] : false;
 716                         $p['dbname'] = isset( $p['dbname'] ) ? $p['dbname'] : false;
 717                         $p['flags'] = isset( $p['flags'] ) ? $p['flags'] : 0;
 718                         $p['variables'] = isset( $p['variables'] ) ? $p['variables'] : [];
 719                         $p['tablePrefix'] = isset( $p['tablePrefix'] ) ? $p['tablePrefix'] : 'get from global';
 720                         if ( !isset( $p['schema'] ) ) {
 721                                 $p['schema'] = isset( $defaultSchemas[$dbType] ) ? $defaultSchemas[$dbType] : null;
 722                         }
 723                         $p['foreign'] = isset( $p['foreign'] ) ? $p['foreign'] : false;
 724                         $p['cliMode'] = $wgCommandLineMode;
 725
 726                         return new $class( $p );
 727                 } else {
 728                         return null;
 729                 }
 730         }
 731
 732         protected function installErrorHandler() {
 733                 $this->mPHPError = false;
 734                 $this->htmlErrors = ini_set( 'html_errors', '0' );
 735                 set_error_handler( [ $this, 'connectionErrorHandler' ] );
 736         }
 737
 738         /**
 739          * @return bool|string
 740          */
 741         protected function restoreErrorHandler() {
 742                 restore_error_handler();
 743                 if ( $this->htmlErrors !== false ) {
 744                         ini_set( 'html_errors', $this->htmlErrors );
 745                 }
 746                 if ( $this->mPHPError ) {
 747                         $error = preg_replace( '!\[<a.*</a>\]!', '', $this->mPHPError );
 748                         $error = preg_replace( '!^.*?:\s?(.*)$!', '$1', $error );
 749
 750                         return $error;
 751                 } else {
 752                         return false;
 753                 }
 754         }
 755
 756         /**
 757          * @param int $errno
 758          * @param string $errstr
 759          */
 760         public function connectionErrorHandler( $errno, $errstr ) {
 761                 $this->mPHPError = $errstr;
 762         }
 763
 764         /**
 765          * Create a log context to pass to wfLogDBError or other logging functions.
 766          *
 767          * @param array $extras Additional data to add to context
 768          * @return array
 769          */
 770         protected function getLogContext( array $extras = [] ) {
 771                 return array_merge(
 772                         [
 773                                 'db_server' => $this->mServer,
 774                                 'db_name' => $this->mDBname,
 775                                 'db_user' => $this->mUser,
 776                         ],
 777                         $extras
 778                 );
 779         }
 780
 781         public function close() {
 782                 if ( $this->mConn ) {
 783                         if ( $this->trxLevel() ) {
 784                                 if ( !$this->mTrxAutomatic ) {
 785                                         wfWarn( "Transaction still in progress (from {$this->mTrxFname}), " .
 786                                                 " performing implicit commit before closing connection!" );
 787                                 }
 788
 789                                 $this->commit( __METHOD__, self::FLUSHING_INTERNAL );
 790                         }
 791
 792                         $closed = $this->closeConnection();
 793                         $this->mConn = false;
 794                 } elseif ( $this->mTrxIdleCallbacks || $this->mTrxEndCallbacks ) { // sanity
 795                         throw new MWException( "Transaction callbacks still pending." );
 796                 } else {
 797                         $closed = true;
 798                 }
 799                 $this->mOpened = false;
 800
 801                 return $closed;
 802         }
 803
 804         /**
 805          * Make sure isOpen() returns true as a sanity check
 806          *
 807          * @throws DBUnexpectedError
 808          */
 809         protected function assertOpen() {
 810                 if ( !$this->isOpen() ) {
 811                         throw new DBUnexpectedError( $this, "DB connection was already closed." );
 812                 }
 813         }
 814
 815         /**
 816          * Closes underlying database connection
 817          * @since 1.20
 818          * @return bool Whether connection was closed successfully
 819          */
 820         abstract protected function closeConnection();
 821
 822         function reportConnectionError( $error = 'Unknown error' ) {
 823                 $myError = $this->lastError();
 824                 if ( $myError ) {
 825                         $error = $myError;
 826                 }
 827
 828                 # New method
 829                 throw new DBConnectionError( $this, $error );
 830         }
 831
 832         /**
 833          * The DBMS-dependent part of query()
 834          *
 835          * @param string $sql SQL query.
 836          * @return ResultWrapper|bool Result object to feed to fetchObject,
 837          *   fetchRow, ...; or false on failure
 838          */
 839         abstract protected function doQuery( $sql );
 840
 841         /**
 842          * Determine whether a query writes to the DB.
 843          * Should return true if unsure.
 844          *
 845          * @param string $sql
 846          * @return bool
 847          */
 848         protected function isWriteQuery( $sql ) {
 849                 return !preg_match(
 850                         '/^(?:SELECT|BEGIN|ROLLBACK|COMMIT|SET|SHOW|EXPLAIN|\(SELECT)\b/i', $sql );
 851         }
 852
 853         /**
 854          * @param $sql
 855          * @return string|null
 856          */
 857         protected function getQueryVerb( $sql ) {
 858                 return preg_match( '/^\s*([a-z]+)/i', $sql, $m ) ? strtoupper( $m[1] ) : null;
 859         }
 860
 861         /**
 862          * Determine whether a SQL statement is sensitive to isolation level.
 863          * A SQL statement is considered transactable if its result could vary
 864          * depending on the transaction isolation level. Operational commands
 865          * such as 'SET' and 'SHOW' are not considered to be transactable.
 866          *
 867          * @param string $sql
 868          * @return bool
 869          */
 870         protected function isTransactableQuery( $sql ) {
 871                 $verb = $this->getQueryVerb( $sql );
 872                 return !in_array( $verb, [ 'BEGIN', 'COMMIT', 'ROLLBACK', 'SHOW', 'SET' ], true );
 873         }
 874
 875         public function query( $sql, $fname = __METHOD__, $tempIgnore = false ) {
 876                 global $wgUser;
 877
 878                 $priorWritesPending = $this->writesOrCallbacksPending();
 879                 $this->mLastQuery = $sql;
 880
 881                 $isWrite = $this->isWriteQuery( $sql );
 882                 if ( $isWrite ) {
 883                         $reason = $this->getReadOnlyReason();
 884                         if ( $reason !== false ) {
 885                                 throw new DBReadOnlyError( $this, "Database is read-only: $reason" );
 886                         }
 887                         # Set a flag indicating that writes have been done
 888                         $this->mDoneWrites = microtime( true );
 889                 }
 890
 891                 # Add a comment for easy SHOW PROCESSLIST interpretation
 892                 if ( is_object( $wgUser ) && $wgUser->isItemLoaded( 'name' ) ) {
 893                         $userName = $wgUser->getName();
 894                         if ( mb_strlen( $userName ) > 15 ) {
 895                                 $userName = mb_substr( $userName, 0, 15 ) . '...';
 896                         }
 897                         $userName = str_replace( '/', '', $userName );
 898                 } else {
 899                         $userName = '';
 900                 }
 901
 902                 // Add trace comment to the begin of the sql string, right after the operator.
 903                 // Or, for one-word queries (like "BEGIN" or COMMIT") add it to the end (bug 42598)
 904                 $commentedSql = preg_replace( '/\s|$/', " /* $fname $userName */ ", $sql, 1 );
 905
 906                 # Start implicit transactions that wrap the request if DBO_TRX is enabled
 907                 if ( !$this->mTrxLevel && $this->getFlag( DBO_TRX )
 908                         && $this->isTransactableQuery( $sql )
 909                 ) {
 910                         $this->begin( __METHOD__ . " ($fname)", self::TRANSACTION_INTERNAL );
 911                         $this->mTrxAutomatic = true;
 912                 }
 913
 914                 # Keep track of whether the transaction has write queries pending
 915                 if ( $this->mTrxLevel && !$this->mTrxDoneWrites && $isWrite ) {
 916                         $this->mTrxDoneWrites = true;
 917                         $this->getTransactionProfiler()->transactionWritingIn(
 918                                 $this->mServer, $this->mDBname, $this->mTrxShortId );
 919                 }
 920
 921                 if ( $this->debug() ) {
 922                         wfDebugLog( 'queries', sprintf( "%s: %s", $this->mDBname, $commentedSql ) );
 923                 }
 924
 925                 # Avoid fatals if close() was called
 926                 $this->assertOpen();
 927
 928                 # Send the query to the server
 929                 $ret = $this->doProfiledQuery( $sql, $commentedSql, $isWrite, $fname );
 930
 931                 # Try reconnecting if the connection was lost
 932                 if ( false === $ret && $this->wasErrorReissuable() ) {
 933                         $recoverable = $this->canRecoverFromDisconnect( $sql, $priorWritesPending );
 934                         # Stash the last error values before anything might clear them
 935                         $lastError = $this->lastError();
 936                         $lastErrno = $this->lastErrno();
 937                         # Update state tracking to reflect transaction loss due to disconnection
 938                         $this->handleTransactionLoss();
 939                         wfDebug( "Connection lost, reconnecting...\n" );
 940                         if ( $this->reconnect() ) {
 941                                 wfDebug( "Reconnected\n" );
 942                                 $msg = __METHOD__ . ": lost connection to {$this->getServer()}; reconnected";
 943                                 wfDebugLog( 'DBPerformance', "$msg:\n" . wfBacktrace( true ) );
 944
 945                                 if ( !$recoverable ) {
 946                                         # Callers may catch the exception and continue to use the DB
 947                                         $this->reportQueryError( $lastError, $lastErrno, $sql, $fname );
 948                                 } else {
 949                                         # Should be safe to silently retry the query
 950                                         $ret = $this->doProfiledQuery( $sql, $commentedSql, $isWrite, $fname );
 951                                 }
 952                         } else {
 953                                 wfDebug( "Failed\n" );
 954                         }
 955                 }
 956
 957                 if ( false === $ret ) {
 958                         # Deadlocks cause the entire transaction to abort, not just the statement.
 959                         # http://dev.mysql.com/doc/refman/5.7/en/innodb-error-handling.html
 960                         # https://www.postgresql.org/docs/9.1/static/explicit-locking.html
 961                         if ( $this->wasDeadlock() ) {
 962                                 if ( $this->explicitTrxActive() || $priorWritesPending ) {
 963                                         $tempIgnore = false; // not recoverable
 964                                 }
 965                                 # Update state tracking to reflect transaction loss
 966                                 $this->handleTransactionLoss();
 967                         }
 968
 969                         $this->reportQueryError(
 970                                 $this->lastError(), $this->lastErrno(), $sql, $fname, $tempIgnore );
 971                 }
 972
 973                 $res = $this->resultObject( $ret );
 974
 975                 return $res;
 976         }
 977
 978         private function doProfiledQuery( $sql, $commentedSql, $isWrite, $fname ) {
 979                 $isMaster = !is_null( $this->getLBInfo( 'master' ) );
 980                 # generalizeSQL() will probably cut down the query to reasonable
 981                 # logging size most of the time. The substr is really just a sanity check.
 982                 if ( $isMaster ) {
 983                         $queryProf = 'query-m: ' . substr( DatabaseBase::generalizeSQL( $sql ), 0, 255 );
 984                 } else {
 985                         $queryProf = 'query: ' . substr( DatabaseBase::generalizeSQL( $sql ), 0, 255 );
 986                 }
 987
 988                 # Include query transaction state
 989                 $queryProf .= $this->mTrxShortId ? " [TRX#{$this->mTrxShortId}]" : "";
 990
 991                 $startTime = microtime( true );
 992                 $this->profiler->profileIn( $queryProf );
 993                 $ret = $this->doQuery( $commentedSql );
 994                 $this->profiler->profileOut( $queryProf );
 995                 $queryRuntime = max( microtime( true ) - $startTime, 0.0 );
 996
 997                 unset( $queryProfSection ); // profile out (if set)
 998
 999                 if ( $ret !== false ) {
1000                         $this->lastPing = $startTime;
1001                         if ( $isWrite && $this->mTrxLevel ) {
1002                                 $this->updateTrxWriteQueryTime( $sql, $queryRuntime );
1003                                 $this->mTrxWriteCallers[] = $fname;
1004                         }
1005                 }
1006
1007                 if ( $sql === self::PING_QUERY ) {
1008                         $this->mRTTEstimate = $queryRuntime;
1009                 }
1010
1011                 $this->getTransactionProfiler()->recordQueryCompletion(
1012                         $queryProf, $startTime, $isWrite, $this->affectedRows()
1013                 );
1014                 MWDebug::query( $sql, $fname, $isMaster, $queryRuntime );
1015
1016                 return $ret;
1017         }
1018
1019         /**
1020          * Update the estimated run-time of a query, not counting large row lock times
1021          *
1022          * LoadBalancer can be set to rollback transactions that will create huge replication
1023          * lag. It bases this estimate off of pendingWriteQueryDuration(). Certain simple
1024          * queries, like inserting a row can take a long time due to row locking. This method
1025          * uses some simple heuristics to discount those cases.
1026          *
1027          * @param string $sql A SQL write query
1028          * @param float $runtime Total runtime, including RTT
1029          */
1030         private function updateTrxWriteQueryTime( $sql, $runtime ) {
1031                 $indicativeOfSlaveRuntime = true;
1032                 if ( $runtime > self::SLOW_WRITE_SEC ) {
1033                         $verb = $this->getQueryVerb( $sql );
1034                         // insert(), upsert(), replace() are fast unless bulky in size or blocked on locks
1035                         if ( $verb === 'INSERT' ) {
1036                                 $indicativeOfSlaveRuntime = $this->affectedRows() > self::SMALL_WRITE_ROWS;
1037                         } elseif ( $verb === 'REPLACE' ) {
1038                                 $indicativeOfSlaveRuntime = $this->affectedRows() > self::SMALL_WRITE_ROWS / 2;
1039                         }
1040                 }
1041
1042                 $this->mTrxWriteDuration += $runtime;
1043                 $this->mTrxWriteQueryCount += 1;
1044                 if ( $indicativeOfSlaveRuntime ) {
1045                         $this->mTrxWriteAdjDuration += $runtime;
1046                         $this->mTrxWriteAdjQueryCount += 1;
1047                 }
1048         }
1049
1050         private function canRecoverFromDisconnect( $sql, $priorWritesPending ) {
1051                 # Transaction dropped; this can mean lost writes, or REPEATABLE-READ snapshots.
1052                 # Dropped connections also mean that named locks are automatically released.
1053                 # Only allow error suppression in autocommit mode or when the lost transaction
1054                 # didn't matter anyway (aside from DBO_TRX snapshot loss).
1055                 if ( $this->mNamedLocksHeld ) {
1056                         return false; // possible critical section violation
1057                 } elseif ( $sql === 'COMMIT' ) {
1058                         return !$priorWritesPending; // nothing written anyway? (T127428)
1059                 } elseif ( $sql === 'ROLLBACK' ) {
1060                         return true; // transaction lost...which is also what was requested :)
1061                 } elseif ( $this->explicitTrxActive() ) {
1062                         return false; // don't drop atomocity
1063                 } elseif ( $priorWritesPending ) {
1064                         return false; // prior writes lost from implicit transaction
1065                 }
1066
1067                 return true;
1068         }
1069
1070         private function handleTransactionLoss() {
1071                 $this->mTrxLevel = 0;
1072                 $this->mTrxIdleCallbacks = []; // bug 65263
1073                 $this->mTrxPreCommitCallbacks = []; // bug 65263
1074                 try {
1075                         // Handle callbacks in mTrxEndCallbacks
1076                         $this->runOnTransactionIdleCallbacks( self::TRIGGER_ROLLBACK );
1077                         $this->runTransactionListenerCallbacks( self::TRIGGER_ROLLBACK );
1078                         return null;
1079                 } catch ( Exception $e ) {
1080                         // Already logged; move on...
1081                         return $e;
1082                 }
1083         }
1084
1085         public function reportQueryError( $error, $errno, $sql, $fname, $tempIgnore = false ) {
1086                 if ( $this->ignoreErrors() || $tempIgnore ) {
1087                         wfDebug( "SQL ERROR (ignored): $error\n" );
1088                 } else {
1089                         $sql1line = mb_substr( str_replace( "\n", "\\n", $sql ), 0, 5 * 1024 );
1090                         wfLogDBError(
1091                                 "{fname}\t{db_server}\t{errno}\t{error}\t{sql1line}",
1092                                 $this->getLogContext( [
1093                                         'method' => __METHOD__,
1094                                         'errno' => $errno,
1095                                         'error' => $error,
1096                                         'sql1line' => $sql1line,
1097                                         'fname' => $fname,
1098                                 ] )
1099                         );
1100                         wfDebug( "SQL ERROR: " . $error . "\n" );
1101                         throw new DBQueryError( $this, $error, $errno, $sql, $fname );
1102                 }
1103         }
1104
1105         /**
1106          * Intended to be compatible with the PEAR::DB wrapper functions.
1107          * http://pear.php.net/manual/en/package.database.db.intro-execute.php
1108          *
1109          * ? = scalar value, quoted as necessary
1110          * ! = raw SQL bit (a function for instance)
1111          * & = filename; reads the file and inserts as a blob
1112          *     (we don't use this though...)
1113          *
1114          * @param string $sql
1115          * @param string $func
1116          *
1117          * @return array
1118          */
1119         protected function prepare( $sql, $func = 'DatabaseBase::prepare' ) {
1120                 /* MySQL doesn't support prepared statements (yet), so just
1121                  * pack up the query for reference. We'll manually replace
1122                  * the bits later.
1123                  */
1124                 return [ 'query' => $sql, 'func' => $func ];
1125         }
1126
1127         /**
1128          * Free a prepared query, generated by prepare().
1129          * @param string $prepared
1130          */
1131         protected function freePrepared( $prepared ) {
1132                 /* No-op by default */
1133         }
1134
1135         /**
1136          * Execute a prepared query with the various arguments
1137          * @param string $prepared The prepared sql
1138          * @param mixed $args Either an array here, or put scalars as varargs
1139          *
1140          * @return ResultWrapper
1141          */
1142         public function execute( $prepared, $args = null ) {
1143                 if ( !is_array( $args ) ) {
1144                         # Pull the var args
1145                         $args = func_get_args();
1146                         array_shift( $args );
1147                 }
1148
1149                 $sql = $this->fillPrepared( $prepared['query'], $args );
1150
1151                 return $this->query( $sql, $prepared['func'] );
1152         }
1153
1154         /**
1155          * For faking prepared SQL statements on DBs that don't support it directly.
1156          *
1157          * @param string $preparedQuery A 'preparable' SQL statement
1158          * @param array $args Array of Arguments to fill it with
1159          * @return string Executable SQL
1160          */
1161         public function fillPrepared( $preparedQuery, $args ) {
1162                 reset( $args );
1163                 $this->preparedArgs =& $args;
1164
1165                 return preg_replace_callback( '/(\\\\[?!&]|[?!&])/',
1166                         [ &$this, 'fillPreparedArg' ], $preparedQuery );
1167         }
1168
1169         /**
1170          * preg_callback func for fillPrepared()
1171          * The arguments should be in $this->preparedArgs and must not be touched
1172          * while we're doing this.
1173          *
1174          * @param array $matches
1175          * @throws DBUnexpectedError
1176          * @return string
1177          */
1178         protected function fillPreparedArg( $matches ) {
1179                 switch ( $matches[1] ) {
1180                         case '\\?':
1181                                 return '?';
1182                         case '\\!':
1183                                 return '!';
1184                         case '\\&':
1185                                 return '&';
1186                 }
1187
1188                 list( /* $n */, $arg ) = each( $this->preparedArgs );
1189
1190                 switch ( $matches[1] ) {
1191                         case '?':
1192                                 return $this->addQuotes( $arg );
1193                         case '!':
1194                                 return $arg;
1195                         case '&':
1196                                 # return $this->addQuotes( file_get_contents( $arg ) );
1197                                 throw new DBUnexpectedError(
1198                                         $this,
1199                                         '& mode is not implemented. If it\'s really needed, uncomment the line above.'
1200                                 );
1201                         default:
1202                                 throw new DBUnexpectedError(
1203                                         $this,
1204                                         'Received invalid match. This should never happen!'
1205                                 );
1206                 }
1207         }
1208
1209         public function freeResult( $res ) {
1210         }
1211
1212         public function selectField(
1213                 $table, $var, $cond = '', $fname = __METHOD__, $options = []
1214         ) {
1215                 if ( $var === '*' ) { // sanity
1216                         throw new DBUnexpectedError( $this, "Cannot use a * field: got '$var'" );
1217                 }
1218
1219                 if ( !is_array( $options ) ) {
1220                         $options = [ $options ];
1221                 }
1222
1223                 $options['LIMIT'] = 1;
1224
1225                 $res = $this->select( $table, $var, $cond, $fname, $options );
1226                 if ( $res === false || !$this->numRows( $res ) ) {
1227                         return false;
1228                 }
1229
1230                 $row = $this->fetchRow( $res );
1231
1232                 if ( $row !== false ) {
1233                         return reset( $row );
1234                 } else {
1235                         return false;
1236                 }
1237         }
1238
1239         public function selectFieldValues(
1240                 $table, $var, $cond = '', $fname = __METHOD__, $options = [], $join_conds = []
1241         ) {
1242                 if ( $var === '*' ) { // sanity
1243                         throw new DBUnexpectedError( $this, "Cannot use a * field" );
1244                 } elseif ( !is_string( $var ) ) { // sanity
1245                         throw new DBUnexpectedError( $this, "Cannot use an array of fields" );
1246                 }
1247
1248                 if ( !is_array( $options ) ) {
1249                         $options = [ $options ];
1250                 }
1251
1252                 $res = $this->select( $table, $var, $cond, $fname, $options, $join_conds );
1253                 if ( $res === false ) {
1254                         return false;
1255                 }
1256
1257                 $values = [];
1258                 foreach ( $res as $row ) {
1259                         $values[] = $row->$var;
1260                 }
1261
1262                 return $values;
1263         }
1264
1265         /**
1266          * Returns an optional USE INDEX clause to go after the table, and a
1267          * string to go at the end of the query.
1268          *
1269          * @param array $options Associative array of options to be turned into
1270          *   an SQL query, valid keys are listed in the function.
1271          * @return array
1272          * @see DatabaseBase::select()
1273          */
1274         public function makeSelectOptions( $options ) {
1275                 $preLimitTail = $postLimitTail = '';
1276                 $startOpts = '';
1277
1278                 $noKeyOptions = [];
1279
1280                 foreach ( $options as $key => $option ) {
1281                         if ( is_numeric( $key ) ) {
1282                                 $noKeyOptions[$option] = true;
1283                         }
1284                 }
1285
1286                 $preLimitTail .= $this->makeGroupByWithHaving( $options );
1287
1288                 $preLimitTail .= $this->makeOrderBy( $options );
1289
1290                 // if (isset($options['LIMIT'])) {
1291                 //      $tailOpts .= $this->limitResult('', $options['LIMIT'],
1292                 //              isset($options['OFFSET']) ? $options['OFFSET']
1293                 //              : false);
1294                 // }
1295
1296                 if ( isset( $noKeyOptions['FOR UPDATE'] ) ) {
1297                         $postLimitTail .= ' FOR UPDATE';
1298                 }
1299
1300                 if ( isset( $noKeyOptions['LOCK IN SHARE MODE'] ) ) {
1301                         $postLimitTail .= ' LOCK IN SHARE MODE';
1302                 }
1303
1304                 if ( isset( $noKeyOptions['DISTINCT'] ) || isset( $noKeyOptions['DISTINCTROW'] ) ) {
1305                         $startOpts .= 'DISTINCT';
1306                 }
1307
1308                 # Various MySQL extensions
1309                 if ( isset( $noKeyOptions['STRAIGHT_JOIN'] ) ) {
1310                         $startOpts .= ' /*! STRAIGHT_JOIN */';
1311                 }
1312
1313                 if ( isset( $noKeyOptions['HIGH_PRIORITY'] ) ) {
1314                         $startOpts .= ' HIGH_PRIORITY';
1315                 }
1316
1317                 if ( isset( $noKeyOptions['SQL_BIG_RESULT'] ) ) {
1318                         $startOpts .= ' SQL_BIG_RESULT';
1319                 }
1320
1321                 if ( isset( $noKeyOptions['SQL_BUFFER_RESULT'] ) ) {
1322                         $startOpts .= ' SQL_BUFFER_RESULT';
1323                 }
1324
1325                 if ( isset( $noKeyOptions['SQL_SMALL_RESULT'] ) ) {
1326                         $startOpts .= ' SQL_SMALL_RESULT';
1327                 }
1328
1329                 if ( isset( $noKeyOptions['SQL_CALC_FOUND_ROWS'] ) ) {
1330                         $startOpts .= ' SQL_CALC_FOUND_ROWS';
1331                 }
1332
1333                 if ( isset( $noKeyOptions['SQL_CACHE'] ) ) {
1334                         $startOpts .= ' SQL_CACHE';
1335                 }
1336
1337                 if ( isset( $noKeyOptions['SQL_NO_CACHE'] ) ) {
1338                         $startOpts .= ' SQL_NO_CACHE';
1339                 }
1340
1341                 if ( isset( $options['USE INDEX'] ) && is_string( $options['USE INDEX'] ) ) {
1342                         $useIndex = $this->useIndexClause( $options['USE INDEX'] );
1343                 } else {
1344                         $useIndex = '';
1345                 }
1346
1347                 return [ $startOpts, $useIndex, $preLimitTail, $postLimitTail ];
1348         }
1349
1350         /**
1351          * Returns an optional GROUP BY with an optional HAVING
1352          *
1353          * @param array $options Associative array of options
1354          * @return string
1355          * @see DatabaseBase::select()
1356          * @since 1.21
1357          */
1358         public function makeGroupByWithHaving( $options ) {
1359                 $sql = '';
1360                 if ( isset( $options['GROUP BY'] ) ) {
1361                         $gb = is_array( $options['GROUP BY'] )
1362                                 ? implode( ',', $options['GROUP BY'] )
1363                                 : $options['GROUP BY'];
1364                         $sql .= ' GROUP BY ' . $gb;
1365                 }
1366                 if ( isset( $options['HAVING'] ) ) {
1367                         $having = is_array( $options['HAVING'] )
1368                                 ? $this->makeList( $options['HAVING'], LIST_AND )
1369                                 : $options['HAVING'];
1370                         $sql .= ' HAVING ' . $having;
1371                 }
1372
1373                 return $sql;
1374         }
1375
1376         /**
1377          * Returns an optional ORDER BY
1378          *
1379          * @param array $options Associative array of options
1380          * @return string
1381          * @see DatabaseBase::select()
1382          * @since 1.21
1383          */
1384         public function makeOrderBy( $options ) {
1385                 if ( isset( $options['ORDER BY'] ) ) {
1386                         $ob = is_array( $options['ORDER BY'] )
1387                                 ? implode( ',', $options['ORDER BY'] )
1388                                 : $options['ORDER BY'];
1389
1390                         return ' ORDER BY ' . $ob;
1391                 }
1392
1393                 return '';
1394         }
1395
1396         // See IDatabase::select for the docs for this function
1397         public function select( $table, $vars, $conds = '', $fname = __METHOD__,
1398                 $options = [], $join_conds = [] ) {
1399                 $sql = $this->selectSQLText( $table, $vars, $conds, $fname, $options, $join_conds );
1400
1401                 return $this->query( $sql, $fname );
1402         }
1403
1404         public function selectSQLText( $table, $vars, $conds = '', $fname = __METHOD__,
1405                 $options = [], $join_conds = []
1406         ) {
1407                 if ( is_array( $vars ) ) {
1408                         $vars = implode( ',', $this->fieldNamesWithAlias( $vars ) );
1409                 }
1410
1411                 $options = (array)$options;
1412                 $useIndexes = ( isset( $options['USE INDEX'] ) && is_array( $options['USE INDEX'] ) )
1413                         ? $options['USE INDEX']
1414                         : [];
1415
1416                 if ( is_array( $table ) ) {
1417                         $from = ' FROM ' .
1418                                 $this->tableNamesWithUseIndexOrJOIN( $table, $useIndexes, $join_conds );
1419                 } elseif ( $table != '' ) {
1420                         if ( $table[0] == ' ' ) {
1421                                 $from = ' FROM ' . $table;
1422                         } else {
1423                                 $from = ' FROM ' .
1424                                         $this->tableNamesWithUseIndexOrJOIN( [ $table ], $useIndexes, [] );
1425                         }
1426                 } else {
1427                         $from = '';
1428                 }
1429
1430                 list( $startOpts, $useIndex, $preLimitTail, $postLimitTail ) =
1431                         $this->makeSelectOptions( $options );
1432
1433                 if ( !empty( $conds ) ) {
1434                         if ( is_array( $conds ) ) {
1435                                 $conds = $this->makeList( $conds, LIST_AND );
1436                         }
1437                         $sql = "SELECT $startOpts $vars $from $useIndex WHERE $conds $preLimitTail";
1438                 } else {
1439                         $sql = "SELECT $startOpts $vars $from $useIndex $preLimitTail";
1440                 }
1441
1442                 if ( isset( $options['LIMIT'] ) ) {
1443                         $sql = $this->limitResult( $sql, $options['LIMIT'],
1444                                 isset( $options['OFFSET'] ) ? $options['OFFSET'] : false );
1445                 }
1446                 $sql = "$sql $postLimitTail";
1447
1448                 if ( isset( $options['EXPLAIN'] ) ) {
1449                         $sql = 'EXPLAIN ' . $sql;
1450                 }
1451
1452                 return $sql;
1453         }
1454
1455         public function selectRow( $table, $vars, $conds, $fname = __METHOD__,
1456                 $options = [], $join_conds = []
1457         ) {
1458                 $options = (array)$options;
1459                 $options['LIMIT'] = 1;
1460                 $res = $this->select( $table, $vars, $conds, $fname, $options, $join_conds );
1461
1462                 if ( $res === false ) {
1463                         return false;
1464                 }
1465
1466                 if ( !$this->numRows( $res ) ) {
1467                         return false;
1468                 }
1469
1470                 $obj = $this->fetchObject( $res );
1471
1472                 return $obj;
1473         }
1474
1475         public function estimateRowCount(
1476                 $table, $vars = '*', $conds = '', $fname = __METHOD__, $options = []
1477         ) {
1478                 $rows = 0;
1479                 $res = $this->select( $table, [ 'rowcount' => 'COUNT(*)' ], $conds, $fname, $options );
1480
1481                 if ( $res ) {
1482                         $row = $this->fetchRow( $res );
1483                         $rows = ( isset( $row['rowcount'] ) ) ? (int)$row['rowcount'] : 0;
1484                 }
1485
1486                 return $rows;
1487         }
1488
1489         public function selectRowCount(
1490                 $tables, $vars = '*', $conds = '', $fname = __METHOD__, $options = [], $join_conds = []
1491         ) {
1492                 $rows = 0;
1493                 $sql = $this->selectSQLText( $tables, '1', $conds, $fname, $options, $join_conds );
1494                 $res = $this->query( "SELECT COUNT(*) AS rowcount FROM ($sql) tmp_count", $fname );
1495
1496                 if ( $res ) {
1497                         $row = $this->fetchRow( $res );
1498                         $rows = ( isset( $row['rowcount'] ) ) ? (int)$row['rowcount'] : 0;
1499                 }
1500
1501                 return $rows;
1502         }
1503
1504         /**
1505          * Removes most variables from an SQL query and replaces them with X or N for numbers.
1506          * It's only slightly flawed. Don't use for anything important.
1507          *
1508          * @param string $sql A SQL Query
1509          *
1510          * @return string
1511          */
1512         protected static function generalizeSQL( $sql ) {
1513                 # This does the same as the regexp below would do, but in such a way
1514                 # as to avoid crashing php on some large strings.
1515                 # $sql = preg_replace( "/'([^\\\\']|\\\\.)*'|\"([^\\\\\"]|\\\\.)*\"/", "'X'", $sql );
1516
1517                 $sql = str_replace( "\\\\", '', $sql );
1518                 $sql = str_replace( "\\'", '', $sql );
1519                 $sql = str_replace( "\\\"", '', $sql );
1520                 $sql = preg_replace( "/'.*'/s", "'X'", $sql );
1521                 $sql = preg_replace( '/".*"/s', "'X'", $sql );
1522
1523                 # All newlines, tabs, etc replaced by single space
1524                 $sql = preg_replace( '/\s+/', ' ', $sql );
1525
1526                 # All numbers => N,
1527                 # except the ones surrounded by characters, e.g. l10n
1528                 $sql = preg_replace( '/-?\d+(,-?\d+)+/s', 'N,...,N', $sql );
1529                 $sql = preg_replace( '/(?<![a-zA-Z])-?\d+(?![a-zA-Z])/s', 'N', $sql );
1530
1531                 return $sql;
1532         }
1533
1534         public function fieldExists( $table, $field, $fname = __METHOD__ ) {
1535                 $info = $this->fieldInfo( $table, $field );
1536
1537                 return (bool)$info;
1538         }
1539
1540         public function indexExists( $table, $index, $fname = __METHOD__ ) {
1541                 if ( !$this->tableExists( $table ) ) {
1542                         return null;
1543                 }
1544
1545                 $info = $this->indexInfo( $table, $index, $fname );
1546                 if ( is_null( $info ) ) {
1547                         return null;
1548                 } else {
1549                         return $info !== false;
1550                 }
1551         }
1552
1553         public function tableExists( $table, $fname = __METHOD__ ) {
1554                 $table = $this->tableName( $table );
1555                 $old = $this->ignoreErrors( true );
1556                 $res = $this->query( "SELECT 1 FROM $table LIMIT 1", $fname );
1557                 $this->ignoreErrors( $old );
1558
1559                 return (bool)$res;
1560         }
1561
1562         public function indexUnique( $table, $index ) {
1563                 $indexInfo = $this->indexInfo( $table, $index );
1564
1565                 if ( !$indexInfo ) {
1566                         return null;
1567                 }
1568
1569                 return !$indexInfo[0]->Non_unique;
1570         }
1571
1572         /**
1573          * Helper for DatabaseBase::insert().
1574          *
1575          * @param array $options
1576          * @return string
1577          */
1578         protected function makeInsertOptions( $options ) {
1579                 return implode( ' ', $options );
1580         }
1581
1582         public function insert( $table, $a, $fname = __METHOD__, $options = [] ) {
1583                 # No rows to insert, easy just return now
1584                 if ( !count( $a ) ) {
1585                         return true;
1586                 }
1587
1588                 $table = $this->tableName( $table );
1589
1590                 if ( !is_array( $options ) ) {
1591                         $options = [ $options ];
1592                 }
1593
1594                 $fh = null;
1595                 if ( isset( $options['fileHandle'] ) ) {
1596                         $fh = $options['fileHandle'];
1597                 }
1598                 $options = $this->makeInsertOptions( $options );
1599
1600                 if ( isset( $a[0] ) && is_array( $a[0] ) ) {
1601                         $multi = true;
1602                         $keys = array_keys( $a[0] );
1603                 } else {
1604                         $multi = false;
1605                         $keys = array_keys( $a );
1606                 }
1607
1608                 $sql = 'INSERT ' . $options .
1609                         " INTO $table (" . implode( ',', $keys ) . ') VALUES ';
1610
1611                 if ( $multi ) {
1612                         $first = true;
1613                         foreach ( $a as $row ) {
1614                                 if ( $first ) {
1615                                         $first = false;
1616                                 } else {
1617                                         $sql .= ',';
1618                                 }
1619                                 $sql .= '(' . $this->makeList( $row ) . ')';
1620                         }
1621                 } else {
1622                         $sql .= '(' . $this->makeList( $a ) . ')';
1623                 }
1624
1625                 if ( $fh !== null && false === fwrite( $fh, $sql ) ) {
1626                         return false;
1627                 } elseif ( $fh !== null ) {
1628                         return true;
1629                 }
1630
1631                 return (bool)$this->query( $sql, $fname );
1632         }
1633
1634         /**
1635          * Make UPDATE options array for DatabaseBase::makeUpdateOptions
1636          *
1637          * @param array $options
1638          * @return array
1639          */
1640         protected function makeUpdateOptionsArray( $options ) {
1641                 if ( !is_array( $options ) ) {
1642                         $options = [ $options ];
1643                 }
1644
1645                 $opts = [];
1646
1647                 if ( in_array( 'LOW_PRIORITY', $options ) ) {
1648                         $opts[] = $this->lowPriorityOption();
1649                 }
1650
1651                 if ( in_array( 'IGNORE', $options ) ) {
1652                         $opts[] = 'IGNORE';
1653                 }
1654
1655                 return $opts;
1656         }
1657
1658         /**
1659          * Make UPDATE options for the DatabaseBase::update function
1660          *
1661          * @param array $options The options passed to DatabaseBase::update
1662          * @return string
1663          */
1664         protected function makeUpdateOptions( $options ) {
1665                 $opts = $this->makeUpdateOptionsArray( $options );
1666
1667                 return implode( ' ', $opts );
1668         }
1669
1670         function update( $table, $values, $conds, $fname = __METHOD__, $options = [] ) {
1671                 $table = $this->tableName( $table );
1672                 $opts = $this->makeUpdateOptions( $options );
1673                 $sql = "UPDATE $opts $table SET " . $this->makeList( $values, LIST_SET );
1674
1675                 if ( $conds !== [] && $conds !== '*' ) {
1676                         $sql .= " WHERE " . $this->makeList( $conds, LIST_AND );
1677                 }
1678
1679                 return $this->query( $sql, $fname );
1680         }
1681
1682         public function makeList( $a, $mode = LIST_COMMA ) {
1683                 if ( !is_array( $a ) ) {
1684                         throw new DBUnexpectedError( $this, 'DatabaseBase::makeList called with incorrect parameters' );
1685                 }
1686
1687                 $first = true;
1688                 $list = '';
1689
1690                 foreach ( $a as $field => $value ) {
1691                         if ( !$first ) {
1692                                 if ( $mode == LIST_AND ) {
1693                                         $list .= ' AND ';
1694                                 } elseif ( $mode == LIST_OR ) {
1695                                         $list .= ' OR ';
1696                                 } else {
1697                                         $list .= ',';
1698                                 }
1699                         } else {
1700                                 $first = false;
1701                         }
1702
1703                         if ( ( $mode == LIST_AND || $mode == LIST_OR ) && is_numeric( $field ) ) {
1704                                 $list .= "($value)";
1705                         } elseif ( ( $mode == LIST_SET ) && is_numeric( $field ) ) {
1706                                 $list .= "$value";
1707                         } elseif ( ( $mode == LIST_AND || $mode == LIST_OR ) && is_array( $value ) ) {
1708                                 // Remove null from array to be handled separately if found
1709                                 $includeNull = false;
1710                                 foreach ( array_keys( $value, null, true ) as $nullKey ) {
1711                                         $includeNull = true;
1712                                         unset( $value[$nullKey] );
1713                                 }
1714                                 if ( count( $value ) == 0 && !$includeNull ) {
1715                                         throw new MWException( __METHOD__ . ": empty input for field $field" );
1716                                 } elseif ( count( $value ) == 0 ) {
1717                                         // only check if $field is null
1718                                         $list .= "$field IS NULL";
1719                                 } else {
1720                                         // IN clause contains at least one valid element
1721                                         if ( $includeNull ) {
1722                                                 // Group subconditions to ensure correct precedence
1723                                                 $list .= '(';
1724                                         }
1725                                         if ( count( $value ) == 1 ) {
1726                                                 // Special-case single values, as IN isn't terribly efficient
1727                                                 // Don't necessarily assume the single key is 0; we don't
1728                                                 // enforce linear numeric ordering on other arrays here.
1729                                                 $value = array_values( $value )[0];
1730                                                 $list .= $field . " = " . $this->addQuotes( $value );
1731                                         } else {
1732                                                 $list .= $field . " IN (" . $this->makeList( $value ) . ") ";
1733                                         }
1734                                         // if null present in array, append IS NULL
1735                                         if ( $includeNull ) {
1736                                                 $list .= " OR $field IS NULL)";
1737                                         }
1738                                 }
1739                         } elseif ( $value === null ) {
1740                                 if ( $mode == LIST_AND || $mode == LIST_OR ) {
1741                                         $list .= "$field IS ";
1742                                 } elseif ( $mode == LIST_SET ) {
1743                                         $list .= "$field = ";
1744                                 }
1745                                 $list .= 'NULL';
1746                         } else {
1747                                 if ( $mode == LIST_AND || $mode == LIST_OR || $mode == LIST_SET ) {
1748                                         $list .= "$field = ";
1749                                 }
1750                                 $list .= $mode == LIST_NAMES ? $value : $this->addQuotes( $value );
1751                         }
1752                 }
1753
1754                 return $list;
1755         }
1756
1757         public function makeWhereFrom2d( $data, $baseKey, $subKey ) {
1758                 $conds = [];
1759
1760                 foreach ( $data as $base => $sub ) {
1761                         if ( count( $sub ) ) {
1762                                 $conds[] = $this->makeList(
1763                                         [ $baseKey => $base, $subKey => array_keys( $sub ) ],
1764                                         LIST_AND );
1765                         }
1766                 }
1767
1768                 if ( $conds ) {
1769                         return $this->makeList( $conds, LIST_OR );
1770                 } else {
1771                         // Nothing to search for...
1772                         return false;
1773                 }
1774         }
1775
1776         /**
1777          * Return aggregated value alias
1778          *
1779          * @param array $valuedata
1780          * @param string $valuename
1781          *
1782          * @return string
1783          */
1784         public function aggregateValue( $valuedata, $valuename = 'value' ) {
1785                 return $valuename;
1786         }
1787
1788         public function bitNot( $field ) {
1789                 return "(~$field)";
1790         }
1791
1792         public function bitAnd( $fieldLeft, $fieldRight ) {
1793                 return "($fieldLeft & $fieldRight)";
1794         }
1795
1796         public function bitOr( $fieldLeft, $fieldRight ) {
1797                 return "($fieldLeft | $fieldRight)";
1798         }
1799
1800         public function buildConcat( $stringList ) {
1801                 return 'CONCAT(' . implode( ',', $stringList ) . ')';
1802         }
1803
1804         public function buildGroupConcatField(
1805                 $delim, $table, $field, $conds = '', $join_conds = []
1806         ) {
1807                 $fld = "GROUP_CONCAT($field SEPARATOR " . $this->addQuotes( $delim ) . ')';
1808
1809                 return '(' . $this->selectSQLText( $table, $fld, $conds, null, [], $join_conds ) . ')';
1810         }
1811
1812         public function selectDB( $db ) {
1813                 # Stub. Shouldn't cause serious problems if it's not overridden, but
1814                 # if your database engine supports a concept similar to MySQL's
1815                 # databases you may as well.
1816                 $this->mDBname = $db;
1817
1818                 return true;
1819         }
1820
1821         public function getDBname() {
1822                 return $this->mDBname;
1823         }
1824
1825         public function getServer() {
1826                 return $this->mServer;
1827         }
1828
1829         /**
1830          * Format a table name ready for use in constructing an SQL query
1831          *
1832          * This does two important things: it quotes the table names to clean them up,
1833          * and it adds a table prefix if only given a table name with no quotes.
1834          *
1835          * All functions of this object which require a table name call this function
1836          * themselves. Pass the canonical name to such functions. This is only needed
1837          * when calling query() directly.
1838          *
1839          * @note This function does not sanitize user input. It is not safe to use
1840          *   this function to escape user input.
1841          * @param string $name Database table name
1842          * @param string $format One of:
1843          *   quoted - Automatically pass the table name through addIdentifierQuotes()
1844          *            so that it can be used in a query.
1845          *   raw - Do not add identifier quotes to the table name
1846          * @return string Full database name
1847          */
1848         public function tableName( $name, $format = 'quoted' ) {
1849                 global $wgSharedDB, $wgSharedPrefix, $wgSharedTables, $wgSharedSchema;
1850                 # Skip the entire process when we have a string quoted on both ends.
1851                 # Note that we check the end so that we will still quote any use of
1852                 # use of `database`.table. But won't break things if someone wants
1853                 # to query a database table with a dot in the name.
1854                 if ( $this->isQuotedIdentifier( $name ) ) {
1855                         return $name;
1856                 }
1857
1858                 # Lets test for any bits of text that should never show up in a table
1859                 # name. Basically anything like JOIN or ON which are actually part of
1860                 # SQL queries, but may end up inside of the table value to combine
1861                 # sql. Such as how the API is doing.
1862                 # Note that we use a whitespace test rather than a \b test to avoid
1863                 # any remote case where a word like on may be inside of a table name
1864                 # surrounded by symbols which may be considered word breaks.
1865                 if ( preg_match( '/(^|\s)(DISTINCT|JOIN|ON|AS)(\s|$)/i', $name ) !== 0 ) {
1866                         return $name;
1867                 }
1868
1869                 # Split database and table into proper variables.
1870                 # We reverse the explode so that database.table and table both output
1871                 # the correct table.
1872                 $dbDetails = explode( '.', $name, 3 );
1873                 if ( count( $dbDetails ) == 3 ) {
1874                         list( $database, $schema, $table ) = $dbDetails;
1875                         # We don't want any prefix added in this case
1876                         $prefix = '';
1877                 } elseif ( count( $dbDetails ) == 2 ) {
1878                         list( $database, $table ) = $dbDetails;
1879                         # We don't want any prefix added in this case
1880                         # In dbs that support it, $database may actually be the schema
1881                         # but that doesn't affect any of the functionality here
1882                         $prefix = '';
1883                         $schema = null;
1884                 } else {
1885                         list( $table ) = $dbDetails;
1886                         if ( $wgSharedDB !== null # We have a shared database
1887                                 && $this->mForeign == false # We're not working on a foreign database
1888                                 && !$this->isQuotedIdentifier( $table ) # Prevent shared tables listing '`table`'
1889                                 && in_array( $table, $wgSharedTables ) # A shared table is selected
1890                         ) {
1891                                 $database = $wgSharedDB;
1892                                 $schema = $wgSharedSchema === null ? $this->mSchema : $wgSharedSchema;
1893                                 $prefix = $wgSharedPrefix === null ? $this->mTablePrefix : $wgSharedPrefix;
1894                         } else {
1895                                 $database = null;
1896                                 $schema = $this->mSchema; # Default schema
1897                                 $prefix = $this->mTablePrefix; # Default prefix
1898                         }
1899                 }
1900
1901                 # Quote $table and apply the prefix if not quoted.
1902                 # $tableName might be empty if this is called from Database::replaceVars()
1903                 $tableName = "{$prefix}{$table}";
1904                 if ( $format == 'quoted' && !$this->isQuotedIdentifier( $tableName ) && $tableName !== '' ) {
1905                         $tableName = $this->addIdentifierQuotes( $tableName );
1906                 }
1907
1908                 # Quote $schema and merge it with the table name if needed
1909                 if ( strlen( $schema ) ) {
1910                         if ( $format == 'quoted' && !$this->isQuotedIdentifier( $schema ) ) {
1911                                 $schema = $this->addIdentifierQuotes( $schema );
1912                         }
1913                         $tableName = $schema . '.' . $tableName;
1914                 }
1915
1916                 # Quote $database and merge it with the table name if needed
1917                 if ( $database !== null ) {
1918                         if ( $format == 'quoted' && !$this->isQuotedIdentifier( $database ) ) {
1919                                 $database = $this->addIdentifierQuotes( $database );
1920                         }
1921                         $tableName = $database . '.' . $tableName;
1922                 }
1923
1924                 return $tableName;
1925         }
1926
1927         /**
1928          * Fetch a number of table names into an array
1929          * This is handy when you need to construct SQL for joins
1930          *
1931          * Example:
1932          * extract( $dbr->tableNames( 'user', 'watchlist' ) );
1933          * $sql = "SELECT wl_namespace,wl_title FROM $watchlist,$user
1934          *         WHERE wl_user=user_id AND wl_user=$nameWithQuotes";
1935          *
1936          * @return array
1937          */
1938         public function tableNames() {
1939                 $inArray = func_get_args();
1940                 $retVal = [];
1941
1942                 foreach ( $inArray as $name ) {
1943                         $retVal[$name] = $this->tableName( $name );
1944                 }
1945
1946                 return $retVal;
1947         }
1948
1949         /**
1950          * Fetch a number of table names into an zero-indexed numerical array
1951          * This is handy when you need to construct SQL for joins
1952          *
1953          * Example:
1954          * list( $user, $watchlist ) = $dbr->tableNamesN( 'user', 'watchlist' );
1955          * $sql = "SELECT wl_namespace,wl_title FROM $watchlist,$user
1956          *         WHERE wl_user=user_id AND wl_user=$nameWithQuotes";
1957          *
1958          * @return array
1959          */
1960         public function tableNamesN() {
1961                 $inArray = func_get_args();
1962                 $retVal = [];
1963
1964                 foreach ( $inArray as $name ) {
1965                         $retVal[] = $this->tableName( $name );
1966                 }
1967
1968                 return $retVal;
1969         }
1970
1971         /**
1972          * Get an aliased table name
1973          * e.g. tableName AS newTableName
1974          *
1975          * @param string $name Table name, see tableName()
1976          * @param string|bool $alias Alias (optional)
1977          * @return string SQL name for aliased table. Will not alias a table to its own name
1978          */
1979         public function tableNameWithAlias( $name, $alias = false ) {
1980                 if ( !$alias || $alias == $name ) {
1981                         return $this->tableName( $name );
1982                 } else {
1983                         return $this->tableName( $name ) . ' ' . $this->addIdentifierQuotes( $alias );
1984                 }
1985         }
1986
1987         /**
1988          * Gets an array of aliased table names
1989          *
1990          * @param array $tables [ [alias] => table ]
1991          * @return string[] See tableNameWithAlias()
1992          */
1993         public function tableNamesWithAlias( $tables ) {
1994                 $retval = [];
1995                 foreach ( $tables as $alias => $table ) {
1996                         if ( is_numeric( $alias ) ) {
1997                                 $alias = $table;
1998                         }
1999                         $retval[] = $this->tableNameWithAlias( $table, $alias );
2000                 }
2001
2002                 return $retval;
2003         }
2004
2005         /**
2006          * Get an aliased field name
2007          * e.g. fieldName AS newFieldName
2008          *
2009          * @param string $name Field name
2010          * @param string|bool $alias Alias (optional)
2011          * @return string SQL name for aliased field. Will not alias a field to its own name
2012          */
2013         public function fieldNameWithAlias( $name, $alias = false ) {
2014                 if ( !$alias || (string)$alias === (string)$name ) {
2015                         return $name;
2016                 } else {
2017                         return $name . ' AS ' . $this->addIdentifierQuotes( $alias ); // PostgreSQL needs AS
2018                 }
2019         }
2020
2021         /**
2022          * Gets an array of aliased field names
2023          *
2024          * @param array $fields [ [alias] => field ]
2025          * @return string[] See fieldNameWithAlias()
2026          */
2027         public function fieldNamesWithAlias( $fields ) {
2028                 $retval = [];
2029                 foreach ( $fields as $alias => $field ) {
2030                         if ( is_numeric( $alias ) ) {
2031                                 $alias = $field;
2032                         }
2033                         $retval[] = $this->fieldNameWithAlias( $field, $alias );
2034                 }
2035
2036                 return $retval;
2037         }
2038
2039         /**
2040          * Get the aliased table name clause for a FROM clause
2041          * which might have a JOIN and/or USE INDEX clause
2042          *
2043          * @param array $tables ( [alias] => table )
2044          * @param array $use_index Same as for select()
2045          * @param array $join_conds Same as for select()
2046          * @return string
2047          */
2048         protected function tableNamesWithUseIndexOrJOIN(
2049                 $tables, $use_index = [], $join_conds = []
2050         ) {
2051                 $ret = [];
2052                 $retJOIN = [];
2053                 $use_index = (array)$use_index;
2054                 $join_conds = (array)$join_conds;
2055
2056                 foreach ( $tables as $alias => $table ) {
2057                         if ( !is_string( $alias ) ) {
2058                                 // No alias? Set it equal to the table name
2059                                 $alias = $table;
2060                         }
2061                         // Is there a JOIN clause for this table?
2062                         if ( isset( $join_conds[$alias] ) ) {
2063                                 list( $joinType, $conds ) = $join_conds[$alias];
2064                                 $tableClause = $joinType;
2065                                 $tableClause .= ' ' . $this->tableNameWithAlias( $table, $alias );
2066                                 if ( isset( $use_index[$alias] ) ) { // has USE INDEX?
2067                                         $use = $this->useIndexClause( implode( ',', (array)$use_index[$alias] ) );
2068                                         if ( $use != '' ) {
2069                                                 $tableClause .= ' ' . $use;
2070                                         }
2071                                 }
2072                                 $on = $this->makeList( (array)$conds, LIST_AND );
2073                                 if ( $on != '' ) {
2074                                         $tableClause .= ' ON (' . $on . ')';
2075                                 }
2076
2077                                 $retJOIN[] = $tableClause;
2078                         } elseif ( isset( $use_index[$alias] ) ) {
2079                                 // Is there an INDEX clause for this table?
2080                                 $tableClause = $this->tableNameWithAlias( $table, $alias );
2081                                 $tableClause .= ' ' . $this->useIndexClause(
2082                                         implode( ',', (array)$use_index[$alias] )
2083                                 );
2084
2085                                 $ret[] = $tableClause;
2086                         } else {
2087                                 $tableClause = $this->tableNameWithAlias( $table, $alias );
2088
2089                                 $ret[] = $tableClause;
2090                         }
2091                 }
2092
2093                 // We can't separate explicit JOIN clauses with ',', use ' ' for those
2094                 $implicitJoins = !empty( $ret ) ? implode( ',', $ret ) : "";
2095                 $explicitJoins = !empty( $retJOIN ) ? implode( ' ', $retJOIN ) : "";
2096
2097                 // Compile our final table clause
2098                 return implode( ' ', [ $implicitJoins, $explicitJoins ] );
2099         }
2100
2101         /**
2102          * Get the name of an index in a given table.
2103          *
2104          * @param string $index
2105          * @return string
2106          */
2107         protected function indexName( $index ) {
2108                 // Backwards-compatibility hack
2109                 $renamed = [
2110                         'ar_usertext_timestamp' => 'usertext_timestamp',
2111                         'un_user_id' => 'user_id',
2112                         'un_user_ip' => 'user_ip',
2113                 ];
2114
2115                 if ( isset( $renamed[$index] ) ) {
2116                         return $renamed[$index];
2117                 } else {
2118                         return $index;
2119                 }
2120         }
2121
2122         public function addQuotes( $s ) {
2123                 if ( $s instanceof Blob ) {
2124                         $s = $s->fetch();
2125                 }
2126                 if ( $s === null ) {
2127                         return 'NULL';
2128                 } else {
2129                         # This will also quote numeric values. This should be harmless,
2130                         # and protects against weird problems that occur when they really
2131                         # _are_ strings such as article titles and string->number->string
2132                         # conversion is not 1:1.
2133                         return "'" . $this->strencode( $s ) . "'";
2134                 }
2135         }
2136
2137         /**
2138          * Quotes an identifier using `backticks` or "double quotes" depending on the database type.
2139          * MySQL uses `backticks` while basically everything else uses double quotes.
2140          * Since MySQL is the odd one out here the double quotes are our generic
2141          * and we implement backticks in DatabaseMysql.
2142          *
2143          * @param string $s
2144          * @return string
2145          */
2146         public function addIdentifierQuotes( $s ) {
2147                 return '"' . str_replace( '"', '""', $s ) . '"';
2148         }
2149
2150         /**
2151          * Returns if the given identifier looks quoted or not according to
2152          * the database convention for quoting identifiers .
2153          *
2154          * @note Do not use this to determine if untrusted input is safe.
2155          *   A malicious user can trick this function.
2156          * @param string $name
2157          * @return bool
2158          */
2159         public function isQuotedIdentifier( $name ) {
2160                 return $name[0] == '"' && substr( $name, -1, 1 ) == '"';
2161         }
2162
2163         /**
2164          * @param string $s
2165          * @return string
2166          */
2167         protected function escapeLikeInternal( $s ) {
2168                 return addcslashes( $s, '\%_' );
2169         }
2170
2171         public function buildLike() {
2172                 $params = func_get_args();
2173
2174                 if ( count( $params ) > 0 && is_array( $params[0] ) ) {
2175                         $params = $params[0];
2176                 }
2177
2178                 $s = '';
2179
2180                 foreach ( $params as $value ) {
2181                         if ( $value instanceof LikeMatch ) {
2182                                 $s .= $value->toString();
2183                         } else {
2184                                 $s .= $this->escapeLikeInternal( $value );
2185                         }
2186                 }
2187
2188                 return " LIKE {$this->addQuotes( $s )} ";
2189         }
2190
2191         public function anyChar() {
2192                 return new LikeMatch( '_' );
2193         }
2194
2195         public function anyString() {
2196                 return new LikeMatch( '%' );
2197         }
2198
2199         public function nextSequenceValue( $seqName ) {
2200                 return null;
2201         }
2202
2203         /**
2204          * USE INDEX clause. Unlikely to be useful for anything but MySQL. This
2205          * is only needed because a) MySQL must be as efficient as possible due to
2206          * its use on Wikipedia, and b) MySQL 4.0 is kind of dumb sometimes about
2207          * which index to pick. Anyway, other databases might have different
2208          * indexes on a given table. So don't bother overriding this unless you're
2209          * MySQL.
2210          * @param string $index
2211          * @return string
2212          */
2213         public function useIndexClause( $index ) {
2214                 return '';
2215         }
2216
2217         public function replace( $table, $uniqueIndexes, $rows, $fname = __METHOD__ ) {
2218                 $quotedTable = $this->tableName( $table );
2219
2220                 if ( count( $rows ) == 0 ) {
2221                         return;
2222                 }
2223
2224                 # Single row case
2225                 if ( !is_array( reset( $rows ) ) ) {
2226                         $rows = [ $rows ];
2227                 }
2228
2229                 // @FXIME: this is not atomic, but a trx would break affectedRows()
2230                 foreach ( $rows as $row ) {
2231                         # Delete rows which collide
2232                         if ( $uniqueIndexes ) {
2233                                 $sql = "DELETE FROM $quotedTable WHERE ";
2234                                 $first = true;
2235                                 foreach ( $uniqueIndexes as $index ) {
2236                                         if ( $first ) {
2237                                                 $first = false;
2238                                                 $sql .= '( ';
2239                                         } else {
2240                                                 $sql .= ' ) OR ( ';
2241                                         }
2242                                         if ( is_array( $index ) ) {
2243                                                 $first2 = true;
2244                                                 foreach ( $index as $col ) {
2245                                                         if ( $first2 ) {
2246                                                                 $first2 = false;
2247                                                         } else {
2248                                                                 $sql .= ' AND ';
2249                                                         }
2250                                                         $sql .= $col . '=' . $this->addQuotes( $row[$col] );
2251                                                 }
2252                                         } else {
2253                                                 $sql .= $index . '=' . $this->addQuotes( $row[$index] );
2254                                         }
2255                                 }
2256                                 $sql .= ' )';
2257                                 $this->query( $sql, $fname );
2258                         }
2259
2260                         # Now insert the row
2261                         $this->insert( $table, $row, $fname );
2262                 }
2263         }
2264
2265         /**
2266          * REPLACE query wrapper for MySQL and SQLite, which have a native REPLACE
2267          * statement.
2268          *
2269          * @param string $table Table name
2270          * @param array|string $rows Row(s) to insert
2271          * @param string $fname Caller function name
2272          *
2273          * @return ResultWrapper
2274          */
2275         protected function nativeReplace( $table, $rows, $fname ) {
2276                 $table = $this->tableName( $table );
2277
2278                 # Single row case
2279                 if ( !is_array( reset( $rows ) ) ) {
2280                         $rows = [ $rows ];
2281                 }
2282
2283                 $sql = "REPLACE INTO $table (" . implode( ',', array_keys( $rows[0] ) ) . ') VALUES ';
2284                 $first = true;
2285
2286                 foreach ( $rows as $row ) {
2287                         if ( $first ) {
2288                                 $first = false;
2289                         } else {
2290                                 $sql .= ',';
2291                         }
2292
2293                         $sql .= '(' . $this->makeList( $row ) . ')';
2294                 }
2295
2296                 return $this->query( $sql, $fname );
2297         }
2298
2299         public function upsert( $table, array $rows, array $uniqueIndexes, array $set,
2300                 $fname = __METHOD__
2301         ) {
2302                 if ( !count( $rows ) ) {
2303                         return true; // nothing to do
2304                 }
2305
2306                 if ( !is_array( reset( $rows ) ) ) {
2307                         $rows = [ $rows ];
2308                 }
2309
2310                 if ( count( $uniqueIndexes ) ) {
2311                         $clauses = []; // list WHERE clauses that each identify a single row
2312                         foreach ( $rows as $row ) {
2313                                 foreach ( $uniqueIndexes as $index ) {
2314                                         $index = is_array( $index ) ? $index : [ $index ]; // columns
2315                                         $rowKey = []; // unique key to this row
2316                                         foreach ( $index as $column ) {
2317                                                 $rowKey[$column] = $row[$column];
2318                                         }
2319                                         $clauses[] = $this->makeList( $rowKey, LIST_AND );
2320                                 }
2321                         }
2322                         $where = [ $this->makeList( $clauses, LIST_OR ) ];
2323                 } else {
2324                         $where = false;
2325                 }
2326
2327                 $useTrx = !$this->mTrxLevel;
2328                 if ( $useTrx ) {
2329                         $this->begin( $fname, self::TRANSACTION_INTERNAL );
2330                 }
2331                 try {
2332                         # Update any existing conflicting row(s)
2333                         if ( $where !== false ) {
2334                                 $ok = $this->update( $table, $set, $where, $fname );
2335                         } else {
2336                                 $ok = true;
2337                         }
2338                         # Now insert any non-conflicting row(s)
2339                         $ok = $this->insert( $table, $rows, $fname, [ 'IGNORE' ] ) && $ok;
2340                 } catch ( Exception $e ) {
2341                         if ( $useTrx ) {
2342                                 $this->rollback( $fname, self::FLUSHING_INTERNAL );
2343                         }
2344                         throw $e;
2345                 }
2346                 if ( $useTrx ) {
2347                         $this->commit( $fname, self::FLUSHING_INTERNAL );
2348                 }
2349
2350                 return $ok;
2351         }
2352
2353         public function deleteJoin( $delTable, $joinTable, $delVar, $joinVar, $conds,
2354                 $fname = __METHOD__
2355         ) {
2356                 if ( !$conds ) {
2357                         throw new DBUnexpectedError( $this,
2358                                 'DatabaseBase::deleteJoin() called with empty $conds' );
2359                 }
2360
2361                 $delTable = $this->tableName( $delTable );
2362                 $joinTable = $this->tableName( $joinTable );
2363                 $sql = "DELETE FROM $delTable WHERE $delVar IN (SELECT $joinVar FROM $joinTable ";
2364                 if ( $conds != '*' ) {
2365                         $sql .= 'WHERE ' . $this->makeList( $conds, LIST_AND );
2366                 }
2367                 $sql .= ')';
2368
2369                 $this->query( $sql, $fname );
2370         }
2371
2372         /**
2373          * Returns the size of a text field, or -1 for "unlimited"
2374          *
2375          * @param string $table
2376          * @param string $field
2377          * @return int
2378          */
2379         public function textFieldSize( $table, $field ) {
2380                 $table = $this->tableName( $table );
2381                 $sql = "SHOW COLUMNS FROM $table LIKE \"$field\";";
2382                 $res = $this->query( $sql, 'DatabaseBase::textFieldSize' );
2383                 $row = $this->fetchObject( $res );
2384
2385                 $m = [];
2386
2387                 if ( preg_match( '/\((.*)\)/', $row->Type, $m ) ) {
2388                         $size = $m[1];
2389                 } else {
2390                         $size = -1;
2391                 }
2392
2393                 return $size;
2394         }
2395
2396         /**
2397          * A string to insert into queries to show that they're low-priority, like
2398          * MySQL's LOW_PRIORITY. If no such feature exists, return an empty
2399          * string and nothing bad should happen.
2400          *
2401          * @return string Returns the text of the low priority option if it is
2402          *   supported, or a blank string otherwise
2403          */
2404         public function lowPriorityOption() {
2405                 return '';
2406         }
2407
2408         public function delete( $table, $conds, $fname = __METHOD__ ) {
2409                 if ( !$conds ) {
2410                         throw new DBUnexpectedError( $this, 'DatabaseBase::delete() called with no conditions' );
2411                 }
2412
2413                 $table = $this->tableName( $table );
2414                 $sql = "DELETE FROM $table";
2415
2416                 if ( $conds != '*' ) {
2417                         if ( is_array( $conds ) ) {
2418                                 $conds = $this->makeList( $conds, LIST_AND );
2419                         }
2420                         $sql .= ' WHERE ' . $conds;
2421                 }
2422
2423                 return $this->query( $sql, $fname );
2424         }
2425
2426         public function insertSelect(
2427                 $destTable, $srcTable, $varMap, $conds,
2428                 $fname = __METHOD__, $insertOptions = [], $selectOptions = []
2429         ) {
2430                 if ( $this->cliMode ) {
2431                         // For massive migrations with downtime, we don't want to select everything
2432                         // into memory and OOM, so do all this native on the server side if possible.
2433                         return $this->nativeInsertSelect(
2434                                 $destTable,
2435                                 $srcTable,
2436                                 $varMap,
2437                                 $conds,
2438                                 $fname,
2439                                 $insertOptions,
2440                                 $selectOptions
2441                         );
2442                 }
2443
2444                 // For web requests, do a locking SELECT and then INSERT. This puts the SELECT burden
2445                 // on only the master (without needing row-based-replication). It also makes it easy to
2446                 // know how big the INSERT is going to be.
2447                 $fields = [];
2448                 foreach ( $varMap as $dstColumn => $sourceColumnOrSql ) {
2449                         $fields[] = $this->fieldNameWithAlias( $sourceColumnOrSql, $dstColumn );
2450                 }
2451                 $selectOptions[] = 'FOR UPDATE';
2452                 $res = $this->select( $srcTable, implode( ',', $fields ), $conds, $fname, $selectOptions );
2453                 if ( !$res ) {
2454                         return false;
2455                 }
2456
2457                 $rows = [];
2458                 foreach ( $res as $row ) {
2459                         $rows[] = (array)$row;
2460                 }
2461
2462                 return $this->insert( $destTable, $rows, $fname, $insertOptions );
2463         }
2464
2465         public function nativeInsertSelect( $destTable, $srcTable, $varMap, $conds,
2466                 $fname = __METHOD__,
2467                 $insertOptions = [], $selectOptions = []
2468         ) {
2469                 $destTable = $this->tableName( $destTable );
2470
2471                 if ( !is_array( $insertOptions ) ) {
2472                         $insertOptions = [ $insertOptions ];
2473                 }
2474
2475                 $insertOptions = $this->makeInsertOptions( $insertOptions );
2476
2477                 if ( !is_array( $selectOptions ) ) {
2478                         $selectOptions = [ $selectOptions ];
2479                 }
2480
2481                 list( $startOpts, $useIndex, $tailOpts ) = $this->makeSelectOptions( $selectOptions );
2482
2483                 if ( is_array( $srcTable ) ) {
2484                         $srcTable = implode( ',', array_map( [ &$this, 'tableName' ], $srcTable ) );
2485                 } else {
2486                         $srcTable = $this->tableName( $srcTable );
2487                 }
2488
2489                 $sql = "INSERT $insertOptions INTO $destTable (" . implode( ',', array_keys( $varMap ) ) . ')' .
2490                         " SELECT $startOpts " . implode( ',', $varMap ) .
2491                         " FROM $srcTable $useIndex ";
2492
2493                 if ( $conds != '*' ) {
2494                         if ( is_array( $conds ) ) {
2495                                 $conds = $this->makeList( $conds, LIST_AND );
2496                         }
2497                         $sql .= " WHERE $conds";
2498                 }
2499
2500                 $sql .= " $tailOpts";
2501
2502                 return $this->query( $sql, $fname );
2503         }
2504
2505         /**
2506          * Construct a LIMIT query with optional offset. This is used for query
2507          * pages. The SQL should be adjusted so that only the first $limit rows
2508          * are returned. If $offset is provided as well, then the first $offset
2509          * rows should be discarded, and the next $limit rows should be returned.
2510          * If the result of the query is not ordered, then the rows to be returned
2511          * are theoretically arbitrary.
2512          *
2513          * $sql is expected to be a SELECT, if that makes a difference.
2514          *
2515          * The version provided by default works in MySQL and SQLite. It will very
2516          * likely need to be overridden for most other DBMSes.
2517          *
2518          * @param string $sql SQL query we will append the limit too
2519          * @param int $limit The SQL limit
2520          * @param int|bool $offset The SQL offset (default false)
2521          * @throws DBUnexpectedError
2522          * @return string
2523          */
2524         public function limitResult( $sql, $limit, $offset = false ) {
2525                 if ( !is_numeric( $limit ) ) {
2526                         throw new DBUnexpectedError( $this, "Invalid non-numeric limit passed to limitResult()\n" );
2527                 }
2528
2529                 return "$sql LIMIT "
2530                         . ( ( is_numeric( $offset ) && $offset != 0 ) ? "{$offset}," : "" )
2531                         . "{$limit} ";
2532         }
2533
2534         public function unionSupportsOrderAndLimit() {
2535                 return true; // True for almost every DB supported
2536         }
2537
2538         public function unionQueries( $sqls, $all ) {
2539                 $glue = $all ? ') UNION ALL (' : ') UNION (';
2540
2541                 return '(' . implode( $glue, $sqls ) . ')';
2542         }
2543
2544         public function conditional( $cond, $trueVal, $falseVal ) {
2545                 if ( is_array( $cond ) ) {
2546                         $cond = $this->makeList( $cond, LIST_AND );
2547                 }
2548
2549                 return " (CASE WHEN $cond THEN $trueVal ELSE $falseVal END) ";
2550         }
2551
2552         public function strreplace( $orig, $old, $new ) {
2553                 return "REPLACE({$orig}, {$old}, {$new})";
2554         }
2555
2556         public function getServerUptime() {
2557                 return 0;
2558         }
2559
2560         public function wasDeadlock() {
2561                 return false;
2562         }
2563
2564         public function wasLockTimeout() {
2565                 return false;
2566         }
2567
2568         public function wasErrorReissuable() {
2569                 return false;
2570         }
2571
2572         public function wasReadOnlyError() {
2573                 return false;
2574         }
2575
2576         /**
2577          * Determines if the given query error was a connection drop
2578          * STUB
2579          *
2580          * @param integer|string $errno
2581          * @return bool
2582          */
2583         public function wasConnectionError( $errno ) {
2584                 return false;
2585         }
2586
2587         /**
2588          * Perform a deadlock-prone transaction.
2589          *
2590          * This function invokes a callback function to perform a set of write
2591          * queries. If a deadlock occurs during the processing, the transaction
2592          * will be rolled back and the callback function will be called again.
2593          *
2594          * Avoid using this method outside of Job or Maintenance classes.
2595          *
2596          * Usage:
2597          *   $dbw->deadlockLoop( callback, ... );
2598          *
2599          * Extra arguments are passed through to the specified callback function.
2600          * This method requires that no transactions are already active to avoid
2601          * causing premature commits or exceptions.
2602          *
2603          * Returns whatever the callback function returned on its successful,
2604          * iteration, or false on error, for example if the retry limit was
2605          * reached.
2606          *
2607          * @return mixed
2608          * @throws DBUnexpectedError
2609          * @throws Exception
2610          */
2611         public function deadlockLoop() {
2612                 $args = func_get_args();
2613                 $function = array_shift( $args );
2614                 $tries = self::DEADLOCK_TRIES;
2615
2616                 $this->begin( __METHOD__ );
2617
2618                 $retVal = null;
2619                 /** @var Exception $e */
2620                 $e = null;
2621                 do {
2622                         try {
2623                                 $retVal = call_user_func_array( $function, $args );
2624                                 break;
2625                         } catch ( DBQueryError $e ) {
2626                                 if ( $this->wasDeadlock() ) {
2627                                         // Retry after a randomized delay
2628                                         usleep( mt_rand( self::DEADLOCK_DELAY_MIN, self::DEADLOCK_DELAY_MAX ) );
2629                                 } else {
2630                                         // Throw the error back up
2631                                         throw $e;
2632                                 }
2633                         }
2634                 } while ( --$tries > 0 );
2635
2636                 if ( $tries <= 0 ) {
2637                         // Too many deadlocks; give up
2638                         $this->rollback( __METHOD__ );
2639                         throw $e;
2640                 } else {
2641                         $this->commit( __METHOD__ );
2642
2643                         return $retVal;
2644                 }
2645         }
2646
2647         public function masterPosWait( DBMasterPos $pos, $timeout ) {
2648                 # Real waits are implemented in the subclass.
2649                 return 0;
2650         }
2651
2652         public function getSlavePos() {
2653                 # Stub
2654                 return false;
2655         }
2656
2657         public function getMasterPos() {
2658                 # Stub
2659                 return false;
2660         }
2661
2662         public function serverIsReadOnly() {
2663                 return false;
2664         }
2665
2666         final public function onTransactionResolution( callable $callback ) {
2667                 if ( !$this->mTrxLevel ) {
2668                         throw new DBUnexpectedError( $this, "No transaction is active." );
2669                 }
2670                 $this->mTrxEndCallbacks[] = [ $callback, wfGetCaller() ];
2671         }
2672
2673         final public function onTransactionIdle( callable $callback ) {
2674                 $this->mTrxIdleCallbacks[] = [ $callback, wfGetCaller() ];
2675                 if ( !$this->mTrxLevel ) {
2676                         $this->runOnTransactionIdleCallbacks( self::TRIGGER_IDLE );
2677                 }
2678         }
2679
2680         final public function onTransactionPreCommitOrIdle( callable $callback ) {
2681                 if ( $this->mTrxLevel ) {
2682                         $this->mTrxPreCommitCallbacks[] = [ $callback, wfGetCaller() ];
2683                 } else {
2684                         // If no transaction is active, then make one for this callback
2685                         $this->startAtomic( __METHOD__ );
2686                         try {
2687                                 call_user_func( $callback );
2688                                 $this->endAtomic( __METHOD__ );
2689                         } catch ( Exception $e ) {
2690                                 $this->rollback( __METHOD__, self::FLUSHING_INTERNAL );
2691                                 throw $e;
2692                         }
2693                 }
2694         }
2695
2696         final public function setTransactionListener( $name, callable $callback = null ) {
2697                 if ( $callback ) {
2698                         $this->mTrxRecurringCallbacks[$name] = [ $callback, wfGetCaller() ];
2699                 } else {
2700                         unset( $this->mTrxRecurringCallbacks[$name] );
2701                 }
2702         }
2703
2704         /**
2705          * Whether to disable running of post-COMMIT/ROLLBACK callbacks
2706          *
2707          * This method should not be used outside of Database/LoadBalancer
2708          *
2709          * @param bool $suppress
2710          * @since 1.28
2711          */
2712         final public function setTrxEndCallbackSuppression( $suppress ) {
2713                 $this->mTrxEndCallbacksSuppressed = $suppress;
2714         }
2715
2716         /**
2717          * Actually run and consume any "on transaction idle/resolution" callbacks.
2718          *
2719          * This method should not be used outside of Database/LoadBalancer
2720          *
2721          * @param integer $trigger IDatabase::TRIGGER_* constant
2722          * @since 1.20
2723          * @throws Exception
2724          */
2725         public function runOnTransactionIdleCallbacks( $trigger ) {
2726                 if ( $this->mTrxEndCallbacksSuppressed ) {
2727                         return;
2728                 }
2729
2730                 $autoTrx = $this->getFlag( DBO_TRX ); // automatic begin() enabled?
2731                 /** @var Exception $e */
2732                 $e = null; // first exception
2733                 do { // callbacks may add callbacks :)
2734                         $callbacks = array_merge(
2735                                 $this->mTrxIdleCallbacks,
2736                                 $this->mTrxEndCallbacks // include "transaction resolution" callbacks
2737                         );
2738                         $this->mTrxIdleCallbacks = []; // consumed (and recursion guard)
2739                         $this->mTrxEndCallbacks = []; // consumed (recursion guard)
2740                         foreach ( $callbacks as $callback ) {
2741                                 try {
2742                                         list( $phpCallback ) = $callback;
2743                                         $this->clearFlag( DBO_TRX ); // make each query its own transaction
2744                                         call_user_func_array( $phpCallback, [ $trigger ] );
2745                                         if ( $autoTrx ) {
2746                                                 $this->setFlag( DBO_TRX ); // restore automatic begin()
2747                                         } else {
2748                                                 $this->clearFlag( DBO_TRX ); // restore auto-commit
2749                                         }
2750                                 } catch ( Exception $ex ) {
2751                                         MWExceptionHandler::logException( $ex );
2752                                         $e = $e ?: $ex;
2753                                         // Some callbacks may use startAtomic/endAtomic, so make sure
2754                                         // their transactions are ended so other callbacks don't fail
2755                                         if ( $this->trxLevel() ) {
2756                                                 $this->rollback( __METHOD__, self::FLUSHING_INTERNAL );
2757                                         }
2758                                 }
2759                         }
2760                 } while ( count( $this->mTrxIdleCallbacks ) );
2761
2762                 if ( $e instanceof Exception ) {
2763                         throw $e; // re-throw any first exception
2764                 }
2765         }
2766
2767         /**
2768          * Actually run and consume any "on transaction pre-commit" callbacks.
2769          *
2770          * This method should not be used outside of Database/LoadBalancer
2771          *
2772          * @since 1.22
2773          * @throws Exception
2774          */
2775         public function runOnTransactionPreCommitCallbacks() {
2776                 $e = null; // first exception
2777                 do { // callbacks may add callbacks :)
2778                         $callbacks = $this->mTrxPreCommitCallbacks;
2779                         $this->mTrxPreCommitCallbacks = []; // consumed (and recursion guard)
2780                         foreach ( $callbacks as $callback ) {
2781                                 try {
2782                                         list( $phpCallback ) = $callback;
2783                                         call_user_func( $phpCallback );
2784                                 } catch ( Exception $ex ) {
2785                                         MWExceptionHandler::logException( $ex );
2786                                         $e = $e ?: $ex;
2787                                 }
2788                         }
2789                 } while ( count( $this->mTrxPreCommitCallbacks ) );
2790
2791                 if ( $e instanceof Exception ) {
2792                         throw $e; // re-throw any first exception
2793                 }
2794         }
2795
2796         /**
2797          * Actually run any "transaction listener" callbacks.
2798          *
2799          * This method should not be used outside of Database/LoadBalancer
2800          *
2801          * @param integer $trigger IDatabase::TRIGGER_* constant
2802          * @throws Exception
2803          * @since 1.20
2804          */
2805         public function runTransactionListenerCallbacks( $trigger ) {
2806                 if ( $this->mTrxEndCallbacksSuppressed ) {
2807                         return;
2808                 }
2809
2810                 /** @var Exception $e */
2811                 $e = null; // first exception
2812
2813                 foreach ( $this->mTrxRecurringCallbacks as $callback ) {
2814                         try {
2815                                 list( $phpCallback ) = $callback;
2816                                 $phpCallback( $trigger, $this );
2817                         } catch ( Exception $ex ) {
2818                                 MWExceptionHandler::logException( $ex );
2819                                 $e = $e ?: $ex;
2820                         }
2821                 }
2822
2823                 if ( $e instanceof Exception ) {
2824                         throw $e; // re-throw any first exception
2825                 }
2826         }
2827
2828         final public function startAtomic( $fname = __METHOD__ ) {
2829                 if ( !$this->mTrxLevel ) {
2830                         $this->begin( $fname, self::TRANSACTION_INTERNAL );
2831                         // If DBO_TRX is set, a series of startAtomic/endAtomic pairs will result
2832                         // in all changes being in one transaction to keep requests transactional.
2833                         if ( !$this->getFlag( DBO_TRX ) ) {
2834                                 $this->mTrxAutomaticAtomic = true;
2835                         }
2836                 }
2837
2838                 $this->mTrxAtomicLevels[] = $fname;
2839         }
2840
2841         final public function endAtomic( $fname = __METHOD__ ) {
2842                 if ( !$this->mTrxLevel ) {
2843                         throw new DBUnexpectedError( $this, "No atomic transaction is open (got $fname)." );
2844                 }
2845                 if ( !$this->mTrxAtomicLevels ||
2846                         array_pop( $this->mTrxAtomicLevels ) !== $fname
2847                 ) {
2848                         throw new DBUnexpectedError( $this, "Invalid atomic section ended (got $fname)." );
2849                 }
2850
2851                 if ( !$this->mTrxAtomicLevels && $this->mTrxAutomaticAtomic ) {
2852                         $this->commit( $fname, self::FLUSHING_INTERNAL );
2853                 }
2854         }
2855
2856         final public function doAtomicSection( $fname, callable $callback ) {
2857                 $this->startAtomic( $fname );
2858                 try {
2859                         $res = call_user_func_array( $callback, [ $this, $fname ] );
2860                 } catch ( Exception $e ) {
2861                         $this->rollback( $fname, self::FLUSHING_INTERNAL );
2862                         throw $e;
2863                 }
2864                 $this->endAtomic( $fname );
2865
2866                 return $res;
2867         }
2868
2869         final public function begin( $fname = __METHOD__, $mode = self::TRANSACTION_EXPLICIT ) {
2870                 // Protect against mismatched atomic section, transaction nesting, and snapshot loss
2871                 if ( $this->mTrxLevel ) {
2872                         if ( $this->mTrxAtomicLevels ) {
2873                                 $levels = implode( ', ', $this->mTrxAtomicLevels );
2874                                 $msg = "$fname: Got explicit BEGIN while atomic section(s) $levels are open.";
2875                                 throw new DBUnexpectedError( $this, $msg );
2876                         } elseif ( !$this->mTrxAutomatic ) {
2877                                 $msg = "$fname: Explicit transaction already active (from {$this->mTrxFname}).";
2878                                 throw new DBUnexpectedError( $this, $msg );
2879                         } else {
2880                                 // @TODO: make this an exception at some point
2881                                 $msg = "$fname: Implicit transaction already active (from {$this->mTrxFname}).";
2882                                 wfLogDBError( $msg );
2883                                 wfWarn( $msg );
2884                                 return; // join the main transaction set
2885                         }
2886                 } elseif ( $this->getFlag( DBO_TRX ) && $mode !== self::TRANSACTION_INTERNAL ) {
2887                         // @TODO: make this an exception at some point
2888                         $msg = "$fname: Implicit transaction expected (DBO_TRX set).";
2889                         wfLogDBError( $msg );
2890                         wfWarn( $msg );
2891                         return; // let any writes be in the main transaction
2892                 }
2893
2894                 // Avoid fatals if close() was called
2895                 $this->assertOpen();
2896
2897                 $this->doBegin( $fname );
2898                 $this->mTrxTimestamp = microtime( true );
2899                 $this->mTrxFname = $fname;
2900                 $this->mTrxDoneWrites = false;
2901                 $this->mTrxAutomatic = ( $mode === self::TRANSACTION_INTERNAL );
2902                 $this->mTrxAutomaticAtomic = false;
2903                 $this->mTrxAtomicLevels = [];
2904                 $this->mTrxShortId = wfRandomString( 12 );
2905                 $this->mTrxWriteDuration = 0.0;
2906                 $this->mTrxWriteQueryCount = 0;
2907                 $this->mTrxWriteAdjDuration = 0.0;
2908                 $this->mTrxWriteAdjQueryCount = 0;
2909                 $this->mTrxWriteCallers = [];
2910                 // First SELECT after BEGIN will establish the snapshot in REPEATABLE-READ.
2911                 // Get an estimate of the slave lag before then, treating estimate staleness
2912                 // as lag itself just to be safe
2913                 $status = $this->getApproximateLagStatus();
2914                 $this->mTrxSlaveLag = $status['lag'] + ( microtime( true ) - $status['since'] );
2915         }
2916
2917         /**
2918          * Issues the BEGIN command to the database server.
2919          *
2920          * @see DatabaseBase::begin()
2921          * @param string $fname
2922          */
2923         protected function doBegin( $fname ) {
2924                 $this->query( 'BEGIN', $fname );
2925                 $this->mTrxLevel = 1;
2926         }
2927
2928         final public function commit( $fname = __METHOD__, $flush = '' ) {
2929                 if ( $this->mTrxLevel && $this->mTrxAtomicLevels ) {
2930                         // There are still atomic sections open. This cannot be ignored
2931                         $levels = implode( ', ', $this->mTrxAtomicLevels );
2932                         throw new DBUnexpectedError(
2933                                 $this,
2934                                 "$fname: Got COMMIT while atomic sections $levels are still open."
2935                         );
2936                 }
2937
2938                 if ( $flush === self::FLUSHING_INTERNAL || $flush === self::FLUSHING_ALL_PEERS ) {
2939                         if ( !$this->mTrxLevel ) {
2940                                 return; // nothing to do
2941                         } elseif ( !$this->mTrxAutomatic ) {
2942                                 throw new DBUnexpectedError(
2943                                         $this,
2944                                         "$fname: Flushing an explicit transaction, getting out of sync."
2945                                 );
2946                         }
2947                 } else {
2948                         if ( !$this->mTrxLevel ) {
2949                                 wfWarn( "$fname: No transaction to commit, something got out of sync." );
2950                                 return; // nothing to do
2951                         } elseif ( $this->mTrxAutomatic ) {
2952                                 // @TODO: make this an exception at some point
2953                                 $msg = "$fname: Explicit commit of implicit transaction.";
2954                                 wfLogDBError( $msg );
2955                                 wfWarn( $msg );
2956                                 return; // wait for the main transaction set commit round
2957                         }
2958                 }
2959
2960                 // Avoid fatals if close() was called
2961                 $this->assertOpen();
2962
2963                 $this->runOnTransactionPreCommitCallbacks();
2964                 $writeTime = $this->pendingWriteQueryDuration();
2965                 $this->doCommit( $fname );
2966                 if ( $this->mTrxDoneWrites ) {
2967                         $this->mDoneWrites = microtime( true );
2968                         $this->getTransactionProfiler()->transactionWritingOut(
2969                                 $this->mServer, $this->mDBname, $this->mTrxShortId, $writeTime );
2970                 }
2971
2972                 $this->runOnTransactionIdleCallbacks( self::TRIGGER_COMMIT );
2973                 $this->runTransactionListenerCallbacks( self::TRIGGER_COMMIT );
2974         }
2975
2976         /**
2977          * Issues the COMMIT command to the database server.
2978          *
2979          * @see DatabaseBase::commit()
2980          * @param string $fname
2981          */
2982         protected function doCommit( $fname ) {
2983                 if ( $this->mTrxLevel ) {
2984                         $this->query( 'COMMIT', $fname );
2985                         $this->mTrxLevel = 0;
2986                 }
2987         }
2988
2989         final public function rollback( $fname = __METHOD__, $flush = '' ) {
2990                 if ( $flush === self::FLUSHING_INTERNAL || $flush === self::FLUSHING_ALL_PEERS ) {
2991                         if ( !$this->mTrxLevel ) {
2992                                 return; // nothing to do
2993                         }
2994                 } else {
2995                         if ( !$this->mTrxLevel ) {
2996                                 wfWarn( "$fname: No transaction to rollback, something got out of sync." );
2997                                 return; // nothing to do
2998                         } elseif ( $this->getFlag( DBO_TRX ) ) {
2999                                 throw new DBUnexpectedError(
3000                                         $this,
3001                                         "$fname: Expected mass rollback of all peer databases (DBO_TRX set)."
3002                                 );
3003                         }
3004                 }
3005
3006                 // Avoid fatals if close() was called
3007                 $this->assertOpen();
3008
3009                 $this->doRollback( $fname );
3010                 $this->mTrxAtomicLevels = [];
3011                 if ( $this->mTrxDoneWrites ) {
3012                         $this->getTransactionProfiler()->transactionWritingOut(
3013                                 $this->mServer, $this->mDBname, $this->mTrxShortId );
3014                 }
3015
3016                 $this->mTrxIdleCallbacks = []; // clear
3017                 $this->mTrxPreCommitCallbacks = []; // clear
3018                 $this->runOnTransactionIdleCallbacks( self::TRIGGER_ROLLBACK );
3019                 $this->runTransactionListenerCallbacks( self::TRIGGER_ROLLBACK );
3020         }
3021
3022         /**
3023          * Issues the ROLLBACK command to the database server.
3024          *
3025          * @see DatabaseBase::rollback()
3026          * @param string $fname
3027          */
3028         protected function doRollback( $fname ) {
3029                 if ( $this->mTrxLevel ) {
3030                         # Disconnects cause rollback anyway, so ignore those errors
3031                         $ignoreErrors = true;
3032                         $this->query( 'ROLLBACK', $fname, $ignoreErrors );
3033                         $this->mTrxLevel = 0;
3034                 }
3035         }
3036
3037         public function clearSnapshot( $fname = __METHOD__ ) {
3038                 if ( $this->writesOrCallbacksPending() || $this->explicitTrxActive() ) {
3039                         // This only flushes transactions to clear snapshots, not to write data
3040                         throw new DBUnexpectedError(
3041                                 $this,
3042                                 "$fname: Cannot COMMIT to clear snapshot because writes are pending."
3043                         );
3044                 }
3045
3046                 $this->commit( $fname, self::FLUSHING_INTERNAL );
3047         }
3048
3049         public function explicitTrxActive() {
3050                 return $this->mTrxLevel && ( $this->mTrxAtomicLevels || !$this->mTrxAutomatic );
3051         }
3052
3053         /**
3054          * Creates a new table with structure copied from existing table
3055          * Note that unlike most database abstraction functions, this function does not
3056          * automatically append database prefix, because it works at a lower
3057          * abstraction level.
3058          * The table names passed to this function shall not be quoted (this
3059          * function calls addIdentifierQuotes when needed).
3060          *
3061          * @param string $oldName Name of table whose structure should be copied
3062          * @param string $newName Name of table to be created
3063          * @param bool $temporary Whether the new table should be temporary
3064          * @param string $fname Calling function name
3065          * @throws MWException
3066          * @return bool True if operation was successful
3067          */
3068         public function duplicateTableStructure( $oldName, $newName, $temporary = false,
3069                 $fname = __METHOD__
3070         ) {
3071                 throw new MWException(
3072                         'DatabaseBase::duplicateTableStructure is not implemented in descendant class' );
3073         }
3074
3075         function listTables( $prefix = null, $fname = __METHOD__ ) {
3076                 throw new MWException( 'DatabaseBase::listTables is not implemented in descendant class' );
3077         }
3078
3079         /**
3080          * Reset the views process cache set by listViews()
3081          * @since 1.22
3082          */
3083         final public function clearViewsCache() {
3084                 $this->allViews = null;
3085         }
3086
3087         /**
3088          * Lists all the VIEWs in the database
3089          *
3090          * For caching purposes the list of all views should be stored in
3091          * $this->allViews. The process cache can be cleared with clearViewsCache()
3092          *
3093          * @param string $prefix Only show VIEWs with this prefix, eg. unit_test_
3094          * @param string $fname Name of calling function
3095          * @throws MWException
3096          * @return array
3097          * @since 1.22
3098          */
3099         public function listViews( $prefix = null, $fname = __METHOD__ ) {
3100                 throw new MWException( 'DatabaseBase::listViews is not implemented in descendant class' );
3101         }
3102
3103         /**
3104          * Differentiates between a TABLE and a VIEW
3105          *
3106          * @param string $name Name of the database-structure to test.
3107          * @throws MWException
3108          * @return bool
3109          * @since 1.22
3110          */
3111         public function isView( $name ) {
3112                 throw new MWException( 'DatabaseBase::isView is not implemented in descendant class' );
3113         }
3114
3115         public function timestamp( $ts = 0 ) {
3116                 return wfTimestamp( TS_MW, $ts );
3117         }
3118
3119         public function timestampOrNull( $ts = null ) {
3120                 if ( is_null( $ts ) ) {
3121                         return null;
3122                 } else {
3123                         return $this->timestamp( $ts );
3124                 }
3125         }
3126
3127         /**
3128          * Take the result from a query, and wrap it in a ResultWrapper if
3129          * necessary. Boolean values are passed through as is, to indicate success
3130          * of write queries or failure.
3131          *
3132          * Once upon a time, DatabaseBase::query() returned a bare MySQL result
3133          * resource, and it was necessary to call this function to convert it to
3134          * a wrapper. Nowadays, raw database objects are never exposed to external
3135          * callers, so this is unnecessary in external code.
3136          *
3137          * @param bool|ResultWrapper|resource|object $result
3138          * @return bool|ResultWrapper
3139          */
3140         protected function resultObject( $result ) {
3141                 if ( !$result ) {
3142                         return false;
3143                 } elseif ( $result instanceof ResultWrapper ) {
3144                         return $result;
3145                 } elseif ( $result === true ) {
3146                         // Successful write query
3147                         return $result;
3148                 } else {
3149                         return new ResultWrapper( $this, $result );
3150                 }
3151         }
3152
3153         public function ping( &$rtt = null ) {
3154                 // Avoid hitting the server if it was hit recently
3155                 if ( $this->isOpen() && ( microtime( true ) - $this->lastPing ) < self::PING_TTL ) {
3156                         if ( !func_num_args() || $this->mRTTEstimate > 0 ) {
3157                                 $rtt = $this->mRTTEstimate;
3158                                 return true; // don't care about $rtt
3159                         }
3160                 }
3161
3162                 // This will reconnect if possible or return false if not
3163                 $this->clearFlag( DBO_TRX, self::REMEMBER_PRIOR );
3164                 $ok = ( $this->query( self::PING_QUERY, __METHOD__, true ) !== false );
3165                 $this->restoreFlags( self::RESTORE_PRIOR );
3166
3167                 if ( $ok ) {
3168                         $rtt = $this->mRTTEstimate;
3169                 }
3170
3171                 return $ok;
3172         }
3173
3174         /**
3175          * @return bool
3176          */
3177         protected function reconnect() {
3178                 $this->closeConnection();
3179                 $this->mOpened = false;
3180                 $this->mConn = false;
3181                 try {
3182                         $this->open( $this->mServer, $this->mUser, $this->mPassword, $this->mDBname );
3183                         $this->lastPing = microtime( true );
3184                         $ok = true;
3185                 } catch ( DBConnectionError $e ) {
3186                         $ok = false;
3187                 }
3188
3189                 return $ok;
3190         }
3191
3192         public function getSessionLagStatus() {
3193                 return $this->getTransactionLagStatus() ?: $this->getApproximateLagStatus();
3194         }
3195
3196         /**
3197          * Get the slave lag when the current transaction started
3198          *
3199          * This is useful when transactions might use snapshot isolation
3200          * (e.g. REPEATABLE-READ in innodb), so the "real" lag of that data
3201          * is this lag plus transaction duration. If they don't, it is still
3202          * safe to be pessimistic. This returns null if there is no transaction.
3203          *
3204          * @return array|null ('lag': seconds or false on error, 'since': UNIX timestamp of BEGIN)
3205          * @since 1.27
3206          */
3207         public function getTransactionLagStatus() {
3208                 return $this->mTrxLevel
3209                         ? [ 'lag' => $this->mTrxSlaveLag, 'since' => $this->trxTimestamp() ]
3210                         : null;
3211         }
3212
3213         /**
3214          * Get a slave lag estimate for this server
3215          *
3216          * @return array ('lag': seconds or false on error, 'since': UNIX timestamp of estimate)
3217          * @since 1.27
3218          */
3219         public function getApproximateLagStatus() {
3220                 return [
3221                         'lag'   => $this->getLBInfo( 'slave' ) ? $this->getLag() : 0,
3222                         'since' => microtime( true )
3223                 ];
3224         }
3225
3226         /**
3227          * Merge the result of getSessionLagStatus() for several DBs
3228          * using the most pessimistic values to estimate the lag of
3229          * any data derived from them in combination
3230          *
3231          * This is information is useful for caching modules
3232          *
3233          * @see WANObjectCache::set()
3234          * @see WANObjectCache::getWithSetCallback()
3235          *
3236          * @param IDatabase $db1
3237          * @param IDatabase ...
3238          * @return array Map of values:
3239          *   - lag: highest lag of any of the DBs or false on error (e.g. replication stopped)
3240          *   - since: oldest UNIX timestamp of any of the DB lag estimates
3241          *   - pending: whether any of the DBs have uncommitted changes
3242          * @since 1.27
3243          */
3244         public static function getCacheSetOptions( IDatabase $db1 ) {
3245                 $res = [ 'lag' => 0, 'since' => INF, 'pending' => false ];
3246                 foreach ( func_get_args() as $db ) {
3247                         /** @var IDatabase $db */
3248                         $status = $db->getSessionLagStatus();
3249                         if ( $status['lag'] === false ) {
3250                                 $res['lag'] = false;
3251                         } elseif ( $res['lag'] !== false ) {
3252                                 $res['lag'] = max( $res['lag'], $status['lag'] );
3253                         }
3254                         $res['since'] = min( $res['since'], $status['since'] );
3255                         $res['pending'] = $res['pending'] ?: $db->writesPending();
3256                 }
3257
3258                 return $res;
3259         }
3260
3261         public function getLag() {
3262                 return 0;
3263         }
3264
3265         function maxListLen() {
3266                 return 0;
3267         }
3268
3269         public function encodeBlob( $b ) {
3270                 return $b;
3271         }
3272
3273         public function decodeBlob( $b ) {
3274                 if ( $b instanceof Blob ) {
3275                         $b = $b->fetch();
3276                 }
3277                 return $b;
3278         }
3279
3280         public function setSessionOptions( array $options ) {
3281         }
3282
3283         /**
3284          * Read and execute SQL commands from a file.
3285          *
3286          * Returns true on success, error string or exception on failure (depending
3287          * on object's error ignore settings).
3288          *
3289          * @param string $filename File name to open
3290          * @param bool|callable $lineCallback Optional function called before reading each line
3291          * @param bool|callable $resultCallback Optional function called for each MySQL result
3292          * @param bool|string $fname Calling function name or false if name should be
3293          *   generated dynamically using $filename
3294          * @param bool|callable $inputCallback Optional function called for each
3295          *   complete line sent
3296          * @throws Exception|MWException
3297          * @return bool|string
3298          */
3299         public function sourceFile(
3300                 $filename, $lineCallback = false, $resultCallback = false, $fname = false, $inputCallback = false
3301         ) {
3302                 MediaWiki\suppressWarnings();
3303                 $fp = fopen( $filename, 'r' );
3304                 MediaWiki\restoreWarnings();
3305
3306                 if ( false === $fp ) {
3307                         throw new MWException( "Could not open \"{$filename}\".\n" );
3308                 }
3309
3310                 if ( !$fname ) {
3311                         $fname = __METHOD__ . "( $filename )";
3312                 }
3313
3314                 try {
3315                         $error = $this->sourceStream( $fp, $lineCallback, $resultCallback, $fname, $inputCallback );
3316                 } catch ( Exception $e ) {
3317                         fclose( $fp );
3318                         throw $e;
3319                 }
3320
3321                 fclose( $fp );
3322
3323                 return $error;
3324         }
3325
3326         /**
3327          * Get the full path of a patch file. Originally based on archive()
3328          * from updaters.inc. Keep in mind this always returns a patch, as
3329          * it fails back to MySQL if no DB-specific patch can be found
3330          *
3331          * @param string $patch The name of the patch, like patch-something.sql
3332          * @return string Full path to patch file
3333          */
3334         public function patchPath( $patch ) {
3335                 global $IP;
3336
3337                 $dbType = $this->getType();
3338                 if ( file_exists( "$IP/maintenance/$dbType/archives/$patch" ) ) {
3339                         return "$IP/maintenance/$dbType/archives/$patch";
3340                 } else {
3341                         return "$IP/maintenance/archives/$patch";
3342                 }
3343         }
3344
3345         public function setSchemaVars( $vars ) {
3346                 $this->mSchemaVars = $vars;
3347         }
3348
3349         /**
3350          * Read and execute commands from an open file handle.
3351          *
3352          * Returns true on success, error string or exception on failure (depending
3353          * on object's error ignore settings).
3354          *
3355          * @param resource $fp File handle
3356          * @param bool|callable $lineCallback Optional function called before reading each query
3357          * @param bool|callable $resultCallback Optional function called for each MySQL result
3358          * @param string $fname Calling function name
3359          * @param bool|callable $inputCallback Optional function called for each complete query sent
3360          * @return bool|string
3361          */
3362         public function sourceStream( $fp, $lineCallback = false, $resultCallback = false,
3363                 $fname = __METHOD__, $inputCallback = false
3364         ) {
3365                 $cmd = '';
3366
3367                 while ( !feof( $fp ) ) {
3368                         if ( $lineCallback ) {
3369                                 call_user_func( $lineCallback );
3370                         }
3371
3372                         $line = trim( fgets( $fp ) );
3373
3374                         if ( $line == '' ) {
3375                                 continue;
3376                         }
3377
3378                         if ( '-' == $line[0] && '-' == $line[1] ) {
3379                                 continue;
3380                         }
3381
3382                         if ( $cmd != '' ) {
3383                                 $cmd .= ' ';
3384                         }
3385
3386                         $done = $this->streamStatementEnd( $cmd, $line );
3387
3388                         $cmd .= "$line\n";
3389
3390                         if ( $done || feof( $fp ) ) {
3391                                 $cmd = $this->replaceVars( $cmd );
3392
3393                                 if ( ( $inputCallback && call_user_func( $inputCallback, $cmd ) ) || !$inputCallback ) {
3394                                         $res = $this->query( $cmd, $fname );
3395
3396                                         if ( $resultCallback ) {
3397                                                 call_user_func( $resultCallback, $res, $this );
3398                                         }
3399
3400                                         if ( false === $res ) {
3401                                                 $err = $this->lastError();
3402
3403                                                 return "Query \"{$cmd}\" failed with error code \"$err\".\n";
3404                                         }
3405                                 }
3406                                 $cmd = '';
3407                         }
3408                 }
3409
3410                 return true;
3411         }
3412
3413         /**
3414          * Called by sourceStream() to check if we've reached a statement end
3415          *
3416          * @param string $sql SQL assembled so far
3417          * @param string $newLine New line about to be added to $sql
3418          * @return bool Whether $newLine contains end of the statement
3419          */
3420         public function streamStatementEnd( &$sql, &$newLine ) {
3421                 if ( $this->delimiter ) {
3422                         $prev = $newLine;
3423                         $newLine = preg_replace( '/' . preg_quote( $this->delimiter, '/' ) . '$/', '', $newLine );
3424                         if ( $newLine != $prev ) {
3425                                 return true;
3426                         }
3427                 }
3428
3429                 return false;
3430         }
3431
3432         /**
3433          * Database independent variable replacement. Replaces a set of variables
3434          * in an SQL statement with their contents as given by $this->getSchemaVars().
3435          *
3436          * Supports '{$var}' `{$var}` and / *$var* / (without the spaces) style variables.
3437          *
3438          * - '{$var}' should be used for text and is passed through the database's
3439          *   addQuotes method.
3440          * - `{$var}` should be used for identifiers (e.g. table and database names).
3441          *   It is passed through the database's addIdentifierQuotes method which
3442          *   can be overridden if the database uses something other than backticks.
3443          * - / *_* / or / *$wgDBprefix* / passes the name that follows through the
3444          *   database's tableName method.
3445          * - / *i* / passes the name that follows through the database's indexName method.
3446          * - In all other cases, / *$var* / is left unencoded. Except for table options,
3447          *   its use should be avoided. In 1.24 and older, string encoding was applied.
3448          *
3449          * @param string $ins SQL statement to replace variables in
3450          * @return string The new SQL statement with variables replaced
3451          */
3452         protected function replaceVars( $ins ) {
3453                 $vars = $this->getSchemaVars();
3454                 return preg_replace_callback(
3455                         '!
3456                                 /\* (\$wgDBprefix|[_i]) \*/ (\w*) | # 1-2. tableName, indexName
3457                                 \'\{\$ (\w+) }\'                  | # 3. addQuotes
3458                                 `\{\$ (\w+) }`                    | # 4. addIdentifierQuotes
3459                                 /\*\$ (\w+) \*/                     # 5. leave unencoded
3460                         !x',
3461                         function ( $m ) use ( $vars ) {
3462                                 // Note: Because of <https://bugs.php.net/bug.php?id=51881>,
3463                                 // check for both nonexistent keys *and* the empty string.
3464                                 if ( isset( $m[1] ) && $m[1] !== '' ) {
3465                                         if ( $m[1] === 'i' ) {
3466                                                 return $this->indexName( $m[2] );
3467                                         } else {
3468                                                 return $this->tableName( $m[2] );
3469                                         }
3470                                 } elseif ( isset( $m[3] ) && $m[3] !== '' && array_key_exists( $m[3], $vars ) ) {
3471                                         return $this->addQuotes( $vars[$m[3]] );
3472                                 } elseif ( isset( $m[4] ) && $m[4] !== '' && array_key_exists( $m[4], $vars ) ) {
3473                                         return $this->addIdentifierQuotes( $vars[$m[4]] );
3474                                 } elseif ( isset( $m[5] ) && $m[5] !== '' && array_key_exists( $m[5], $vars ) ) {
3475                                         return $vars[$m[5]];
3476                                 } else {
3477                                         return $m[0];
3478                                 }
3479                         },
3480                         $ins
3481                 );
3482         }
3483
3484         /**
3485          * Get schema variables. If none have been set via setSchemaVars(), then
3486          * use some defaults from the current object.
3487          *
3488          * @return array
3489          */
3490         protected function getSchemaVars() {
3491                 if ( $this->mSchemaVars ) {
3492                         return $this->mSchemaVars;
3493                 } else {
3494                         return $this->getDefaultSchemaVars();
3495                 }
3496         }
3497
3498         /**
3499          * Get schema variables to use if none have been set via setSchemaVars().
3500          *
3501          * Override this in derived classes to provide variables for tables.sql
3502          * and SQL patch files.
3503          *
3504          * @return array
3505          */
3506         protected function getDefaultSchemaVars() {
3507                 return [];
3508         }
3509
3510         public function lockIsFree( $lockName, $method ) {
3511                 return true;
3512         }
3513
3514         public function lock( $lockName, $method, $timeout = 5 ) {
3515                 $this->mNamedLocksHeld[$lockName] = 1;
3516
3517                 return true;
3518         }
3519
3520         public function unlock( $lockName, $method ) {
3521                 unset( $this->mNamedLocksHeld[$lockName] );
3522
3523                 return true;
3524         }
3525
3526         public function getScopedLockAndFlush( $lockKey, $fname, $timeout ) {
3527                 if ( $this->writesOrCallbacksPending() ) {
3528                         // This only flushes transactions to clear snapshots, not to write data
3529                         throw new DBUnexpectedError(
3530                                 $this,
3531                                 "$fname: Cannot COMMIT to clear snapshot because writes are pending."
3532                         );
3533                 }
3534
3535                 if ( !$this->lock( $lockKey, $fname, $timeout ) ) {
3536                         return null;
3537                 }
3538
3539                 $unlocker = new ScopedCallback( function () use ( $lockKey, $fname ) {
3540                         if ( $this->trxLevel() ) {
3541                                 // There is a good chance an exception was thrown, causing any early return
3542                                 // from the caller. Let any error handler get a chance to issue rollback().
3543                                 // If there isn't one, let the error bubble up and trigger server-side rollback.
3544                                 $this->onTransactionResolution( function () use ( $lockKey, $fname ) {
3545                                         $this->unlock( $lockKey, $fname );
3546                                 } );
3547                         } else {
3548                                 $this->unlock( $lockKey, $fname );
3549                         }
3550                 } );
3551
3552                 $this->commit( __METHOD__, self::FLUSHING_INTERNAL );
3553
3554                 return $unlocker;
3555         }
3556
3557         public function namedLocksEnqueue() {
3558                 return false;
3559         }
3560
3561         /**
3562          * Lock specific tables
3563          *
3564          * @param array $read Array of tables to lock for read access
3565          * @param array $write Array of tables to lock for write access
3566          * @param string $method Name of caller
3567          * @param bool $lowPriority Whether to indicate writes to be LOW PRIORITY
3568          * @return bool
3569          */
3570         public function lockTables( $read, $write, $method, $lowPriority = true ) {
3571                 return true;
3572         }
3573
3574         /**
3575          * Unlock specific tables
3576          *
3577          * @param string $method The caller
3578          * @return bool
3579          */
3580         public function unlockTables( $method ) {
3581                 return true;
3582         }
3583
3584         /**
3585          * Delete a table
3586          * @param string $tableName
3587          * @param string $fName
3588          * @return bool|ResultWrapper
3589          * @since 1.18
3590          */
3591         public function dropTable( $tableName, $fName = __METHOD__ ) {
3592                 if ( !$this->tableExists( $tableName, $fName ) ) {
3593                         return false;
3594                 }
3595                 $sql = "DROP TABLE " . $this->tableName( $tableName );
3596                 if ( $this->cascadingDeletes() ) {
3597                         $sql .= " CASCADE";
3598                 }
3599
3600                 return $this->query( $sql, $fName );
3601         }
3602
3603         /**
3604          * Get search engine class. All subclasses of this need to implement this
3605          * if they wish to use searching.
3606          *
3607          * @return string
3608          */
3609         public function getSearchEngine() {
3610                 return 'SearchEngineDummy';
3611         }
3612
3613         public function getInfinity() {
3614                 return 'infinity';
3615         }
3616
3617         public function encodeExpiry( $expiry ) {
3618                 return ( $expiry == '' || $expiry == 'infinity' || $expiry == $this->getInfinity() )
3619                         ? $this->getInfinity()
3620                         : $this->timestamp( $expiry );
3621         }
3622
3623         public function decodeExpiry( $expiry, $format = TS_MW ) {
3624                 return ( $expiry == '' || $expiry == 'infinity' || $expiry == $this->getInfinity() )
3625                         ? 'infinity'
3626                         : wfTimestamp( $format, $expiry );
3627         }
3628
3629         public function setBigSelects( $value = true ) {
3630                 // no-op
3631         }
3632
3633         public function isReadOnly() {
3634                 return ( $this->getReadOnlyReason() !== false );
3635         }
3636
3637         /**
3638          * @return string|bool Reason this DB is read-only or false if it is not
3639          */
3640         protected function getReadOnlyReason() {
3641                 $reason = $this->getLBInfo( 'readOnlyReason' );
3642
3643                 return is_string( $reason ) ? $reason : false;
3644         }
3645
3646         /**
3647          * @since 1.19
3648          * @return string
3649          */
3650         public function __toString() {
3651                 return (string)$this->mConn;
3652         }
3653
3654         /**
3655          * Run a few simple sanity checks
3656          */
3657         public function __destruct() {
3658                 if ( $this->mTrxLevel && $this->mTrxDoneWrites ) {
3659                         trigger_error( "Uncommitted DB writes (transaction from {$this->mTrxFname})." );
3660                 }
3661                 $danglingCallbacks = array_merge(
3662                         $this->mTrxIdleCallbacks,
3663                         $this->mTrxPreCommitCallbacks,
3664                         $this->mTrxEndCallbacks
3665                 );
3666                 if ( $danglingCallbacks ) {
3667                         $callers = [];
3668                         foreach ( $danglingCallbacks as $callbackInfo ) {
3669                                 $callers[] = $callbackInfo[1];
3670                         }
3671                         $callers = implode( ', ', $callers );
3672                         trigger_error( "DB transaction callbacks still pending (from $callers)." );
3673                 }
3674         }
3675 }
3676
3677 /**
3678  * @since 1.27
3679  */
3680 abstract class Database extends DatabaseBase {
3681         // B/C until nothing type hints for DatabaseBase
3682         // @TODO: finish renaming DatabaseBase => Database
3683 }