includes/libs/rdbms/database/Database.php

   1 <?php
   2 /**
   3  * @defgroup Database Database
   4  *
   5  * This file deals with database interface functions
   6  * and query specifics/optimisations.
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License along
  19  * with this program; if not, write to the Free Software Foundation, Inc.,
  20  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  21  * http://www.gnu.org/copyleft/gpl.html
  22  *
  23  * @file
  24  * @ingroup Database
  25  */
  26 use Psr\Log\LoggerAwareInterface;
  27 use Psr\Log\LoggerInterface;
  28
  29 /**
  30  * Database abstraction object
  31  * @ingroup Database
  32  */
  33 abstract class Database implements IDatabase, LoggerAwareInterface {
  34         /** Number of times to re-try an operation in case of deadlock */
  35         const DEADLOCK_TRIES = 4;
  36         /** Minimum time to wait before retry, in microseconds */
  37         const DEADLOCK_DELAY_MIN = 500000;
  38         /** Maximum time to wait before retry */
  39         const DEADLOCK_DELAY_MAX = 1500000;
  40
  41         /** How long before it is worth doing a dummy query to test the connection */
  42         const PING_TTL = 1.0;
  43         const PING_QUERY = 'SELECT 1 AS ping';
  44
  45         const TINY_WRITE_SEC = .010;
  46         const SLOW_WRITE_SEC = .500;
  47         const SMALL_WRITE_ROWS = 100;
  48
  49         /** @var string SQL query */
  50         protected $mLastQuery = '';
  51         /** @var bool */
  52         protected $mDoneWrites = false;
  53         /** @var string|bool */
  54         protected $mPHPError = false;
  55         /** @var string */
  56         protected $mServer;
  57         /** @var string */
  58         protected $mUser;
  59         /** @var string */
  60         protected $mPassword;
  61         /** @var string */
  62         protected $mDBname;
  63         /** @var array[] $aliases Map of (table => (dbname, schema, prefix) map) */
  64         protected $tableAliases = [];
  65         /** @var bool Whether this PHP instance is for a CLI script */
  66         protected $cliMode;
  67         /** @var string Agent name for query profiling */
  68         protected $agent;
  69
  70         /** @var BagOStuff APC cache */
  71         protected $srvCache;
  72         /** @var LoggerInterface */
  73         protected $connLogger;
  74         /** @var LoggerInterface */
  75         protected $queryLogger;
  76         /** @var callback Error logging callback */
  77         protected $errorLogger;
  78
  79         /** @var resource Database connection */
  80         protected $mConn = null;
  81         /** @var bool */
  82         protected $mOpened = false;
  83
  84         /** @var array[] List of (callable, method name) */
  85         protected $mTrxIdleCallbacks = [];
  86         /** @var array[] List of (callable, method name) */
  87         protected $mTrxPreCommitCallbacks = [];
  88         /** @var array[] List of (callable, method name) */
  89         protected $mTrxEndCallbacks = [];
  90         /** @var callable[] Map of (name => callable) */
  91         protected $mTrxRecurringCallbacks = [];
  92         /** @var bool Whether to suppress triggering of transaction end callbacks */
  93         protected $mTrxEndCallbacksSuppressed = false;
  94
  95         /** @var string */
  96         protected $mTablePrefix = '';
  97         /** @var string */
  98         protected $mSchema = '';
  99         /** @var integer */
 100         protected $mFlags;
 101         /** @var array */
 102         protected $mLBInfo = [];
 103         /** @var bool|null */
 104         protected $mDefaultBigSelects = null;
 105         /** @var array|bool */
 106         protected $mSchemaVars = false;
 107         /** @var array */
 108         protected $mSessionVars = [];
 109         /** @var array|null */
 110         protected $preparedArgs;
 111         /** @var string|bool|null Stashed value of html_errors INI setting */
 112         protected $htmlErrors;
 113         /** @var string */
 114         protected $delimiter = ';';
 115         /** @var DatabaseDomain */
 116         protected $currentDomain;
 117
 118         /**
 119          * Either 1 if a transaction is active or 0 otherwise.
 120          * The other Trx fields may not be meaningfull if this is 0.
 121          *
 122          * @var int
 123          */
 124         protected $mTrxLevel = 0;
 125         /**
 126          * Either a short hexidecimal string if a transaction is active or ""
 127          *
 128          * @var string
 129          * @see DatabaseBase::mTrxLevel
 130          */
 131         protected $mTrxShortId = '';
 132         /**
 133          * The UNIX time that the transaction started. Callers can assume that if
 134          * snapshot isolation is used, then the data is *at least* up to date to that
 135          * point (possibly more up-to-date since the first SELECT defines the snapshot).
 136          *
 137          * @var float|null
 138          * @see DatabaseBase::mTrxLevel
 139          */
 140         private $mTrxTimestamp = null;
 141         /** @var float Lag estimate at the time of BEGIN */
 142         private $mTrxReplicaLag = null;
 143         /**
 144          * Remembers the function name given for starting the most recent transaction via begin().
 145          * Used to provide additional context for error reporting.
 146          *
 147          * @var string
 148          * @see DatabaseBase::mTrxLevel
 149          */
 150         private $mTrxFname = null;
 151         /**
 152          * Record if possible write queries were done in the last transaction started
 153          *
 154          * @var bool
 155          * @see DatabaseBase::mTrxLevel
 156          */
 157         private $mTrxDoneWrites = false;
 158         /**
 159          * Record if the current transaction was started implicitly due to DBO_TRX being set.
 160          *
 161          * @var bool
 162          * @see DatabaseBase::mTrxLevel
 163          */
 164         private $mTrxAutomatic = false;
 165         /**
 166          * Array of levels of atomicity within transactions
 167          *
 168          * @var array
 169          */
 170         private $mTrxAtomicLevels = [];
 171         /**
 172          * Record if the current transaction was started implicitly by DatabaseBase::startAtomic
 173          *
 174          * @var bool
 175          */
 176         private $mTrxAutomaticAtomic = false;
 177         /**
 178          * Track the write query callers of the current transaction
 179          *
 180          * @var string[]
 181          */
 182         private $mTrxWriteCallers = [];
 183         /**
 184          * @var float Seconds spent in write queries for the current transaction
 185          */
 186         private $mTrxWriteDuration = 0.0;
 187         /**
 188          * @var integer Number of write queries for the current transaction
 189          */
 190         private $mTrxWriteQueryCount = 0;
 191         /**
 192          * @var float Like mTrxWriteQueryCount but excludes lock-bound, easy to replicate, queries
 193          */
 194         private $mTrxWriteAdjDuration = 0.0;
 195         /**
 196          * @var integer Number of write queries counted in mTrxWriteAdjDuration
 197          */
 198         private $mTrxWriteAdjQueryCount = 0;
 199         /**
 200          * @var float RTT time estimate
 201          */
 202         private $mRTTEstimate = 0.0;
 203
 204         /** @var array Map of (name => 1) for locks obtained via lock() */
 205         private $mNamedLocksHeld = [];
 206         /** @var array Map of (table name => 1) for TEMPORARY tables */
 207         private $mSessionTempTables = [];
 208
 209         /** @var IDatabase|null Lazy handle to the master DB this server replicates from */
 210         private $lazyMasterHandle;
 211
 212         /**
 213          * @since 1.22
 214          * @var string[] Process cache of VIEWs names in the database
 215          */
 216         protected $allViews = null;
 217
 218         /** @var float UNIX timestamp */
 219         protected $lastPing = 0.0;
 220
 221         /** @var int[] Prior mFlags values */
 222         private $priorFlags = [];
 223
 224         /** @var object|string Class name or object With profileIn/profileOut methods */
 225         protected $profiler;
 226         /** @var TransactionProfiler */
 227         protected $trxProfiler;
 228
 229         /**
 230          * Constructor and database handle and attempt to connect to the DB server
 231          *
 232          * IDatabase classes should not be constructed directly in external
 233          * code. Database::factory() should be used instead.
 234          *
 235          * @param array $params Parameters passed from Database::factory()
 236          */
 237         function __construct( array $params ) {
 238                 $server = $params['host'];
 239                 $user = $params['user'];
 240                 $password = $params['password'];
 241                 $dbName = $params['dbname'];
 242
 243                 $this->mSchema = $params['schema'];
 244                 $this->mTablePrefix = $params['tablePrefix'];
 245
 246                 $this->cliMode = $params['cliMode'];
 247                 // Agent name is added to SQL queries in a comment, so make sure it can't break out
 248                 $this->agent = str_replace( '/', '-', $params['agent'] );
 249
 250                 $this->mFlags = $params['flags'];
 251                 if ( $this->mFlags & DBO_DEFAULT ) {
 252                         if ( $this->cliMode ) {
 253                                 $this->mFlags &= ~DBO_TRX;
 254                         } else {
 255                                 $this->mFlags |= DBO_TRX;
 256                         }
 257                 }
 258
 259                 $this->mSessionVars = $params['variables'];
 260
 261                 $this->srvCache = isset( $params['srvCache'] )
 262                         ? $params['srvCache']
 263                         : new HashBagOStuff();
 264
 265                 $this->profiler = $params['profiler'];
 266                 $this->trxProfiler = $params['trxProfiler'];
 267                 $this->connLogger = $params['connLogger'];
 268                 $this->queryLogger = $params['queryLogger'];
 269
 270                 // Set initial dummy domain until open() sets the final DB/prefix
 271                 $this->currentDomain = DatabaseDomain::newUnspecified();
 272
 273                 if ( $user ) {
 274                         $this->open( $server, $user, $password, $dbName );
 275                 } elseif ( $this->requiresDatabaseUser() ) {
 276                         throw new InvalidArgumentException( "No database user provided." );
 277                 }
 278
 279                 // Set the domain object after open() sets the relevant fields
 280                 if ( $this->mDBname != '' ) {
 281                         // Domains with server scope but a table prefix are not used by IDatabase classes
 282                         $this->currentDomain = new DatabaseDomain( $this->mDBname, null, $this->mTablePrefix );
 283                 }
 284         }
 285
 286         /**
 287          * Construct a Database subclass instance given a database type and parameters
 288          *
 289          * This also connects to the database immediately upon object construction
 290          *
 291          * @param string $dbType A possible DB type (sqlite, mysql, postgres)
 292          * @param array $p Parameter map with keys:
 293          *   - host : The hostname of the DB server
 294          *   - user : The name of the database user the client operates under
 295          *   - password : The password for the database user
 296          *   - dbname : The name of the database to use where queries do not specify one.
 297          *      The database must exist or an error might be thrown. Setting this to the empty string
 298          *      will avoid any such errors and make the handle have no implicit database scope. This is
 299          *      useful for queries like SHOW STATUS, CREATE DATABASE, or DROP DATABASE. Note that a
 300          *      "database" in Postgres is rougly equivalent to an entire MySQL server. This the domain
 301          *      in which user names and such are defined, e.g. users are database-specific in Postgres.
 302          *   - schema : The database schema to use (if supported). A "schema" in Postgres is roughly
 303          *      equivalent to a "database" in MySQL. Note that MySQL and SQLite do not use schemas.
 304          *   - tablePrefix : Optional table prefix that is implicitly added on to all table names
 305          *      recognized in queries. This can be used in place of schemas for handle site farms.
 306          *   - flags : Optional bitfield of DBO_* constants that define connection, protocol,
 307          *      buffering, and transaction behavior. It is STRONGLY adviced to leave the DBO_DEFAULT
 308          *      flag in place UNLESS this this database simply acts as a key/value store.
 309          *   - driver: Optional name of a specific DB client driver. For MySQL, there is the old
 310          *      'mysql' driver and the newer 'mysqli' driver.
 311          *   - variables: Optional map of session variables to set after connecting. This can be
 312          *      used to adjust lock timeouts or encoding modes and the like.
 313          *   - connLogger: Optional PSR-3 logger interface instance.
 314          *   - queryLogger: Optional PSR-3 logger interface instance.
 315          *   - profiler: Optional class name or object with profileIn()/profileOut() methods.
 316          *      These will be called in query(), using a simplified version of the SQL that also
 317          *      includes the agent as a SQL comment.
 318          *   - trxProfiler: Optional TransactionProfiler instance.
 319          *   - errorLogger: Optional callback that takes an Exception and logs it.
 320          *   - cliMode: Whether to consider the execution context that of a CLI script.
 321          *   - agent: Optional name used to identify the end-user in query profiling/logging.
 322          *   - srvCache: Optional BagOStuff instance to an APC-style cache.
 323          * @return Database|null If the database driver or extension cannot be found
 324          * @throws InvalidArgumentException If the database driver or extension cannot be found
 325          * @since 1.18
 326          */
 327         final public static function factory( $dbType, $p = [] ) {
 328                 static $canonicalDBTypes = [
 329                         'mysql' => [ 'mysqli', 'mysql' ],
 330                         'postgres' => [],
 331                         'sqlite' => [],
 332                         'oracle' => [],
 333                         'mssql' => [],
 334                 ];
 335
 336                 $driver = false;
 337                 $dbType = strtolower( $dbType );
 338                 if ( isset( $canonicalDBTypes[$dbType] ) && $canonicalDBTypes[$dbType] ) {
 339                         $possibleDrivers = $canonicalDBTypes[$dbType];
 340                         if ( !empty( $p['driver'] ) ) {
 341                                 if ( in_array( $p['driver'], $possibleDrivers ) ) {
 342                                         $driver = $p['driver'];
 343                                 } else {
 344                                         throw new InvalidArgumentException( __METHOD__ .
 345                                                 " type '$dbType' does not support driver '{$p['driver']}'" );
 346                                 }
 347                         } else {
 348                                 foreach ( $possibleDrivers as $posDriver ) {
 349                                         if ( extension_loaded( $posDriver ) ) {
 350                                                 $driver = $posDriver;
 351                                                 break;
 352                                         }
 353                                 }
 354                         }
 355                 } else {
 356                         $driver = $dbType;
 357                 }
 358                 if ( $driver === false ) {
 359                         throw new InvalidArgumentException( __METHOD__ .
 360                                 " no viable database extension found for type '$dbType'" );
 361                 }
 362
 363                 $class = 'Database' . ucfirst( $driver );
 364                 if ( class_exists( $class ) && is_subclass_of( $class, 'IDatabase' ) ) {
 365                         // Resolve some defaults for b/c
 366                         $p['host'] = isset( $p['host'] ) ? $p['host'] : false;
 367                         $p['user'] = isset( $p['user'] ) ? $p['user'] : false;
 368                         $p['password'] = isset( $p['password'] ) ? $p['password'] : false;
 369                         $p['dbname'] = isset( $p['dbname'] ) ? $p['dbname'] : false;
 370                         $p['flags'] = isset( $p['flags'] ) ? $p['flags'] : 0;
 371                         $p['variables'] = isset( $p['variables'] ) ? $p['variables'] : [];
 372                         $p['tablePrefix'] = isset( $p['tablePrefix'] ) ? $p['tablePrefix'] : '';
 373                         $p['schema'] = isset( $p['schema'] ) ? $p['schema'] : '';
 374                         $p['cliMode'] = isset( $p['cliMode'] ) ? $p['cliMode'] : ( PHP_SAPI === 'cli' );
 375                         $p['agent'] = isset( $p['agent'] ) ? $p['agent'] : '';
 376                         if ( !isset( $p['connLogger'] ) ) {
 377                                 $p['connLogger'] = new \Psr\Log\NullLogger();
 378                         }
 379                         if ( !isset( $p['queryLogger'] ) ) {
 380                                 $p['queryLogger'] = new \Psr\Log\NullLogger();
 381                         }
 382                         $p['profiler'] = isset( $p['profiler'] ) ? $p['profiler'] : null;
 383                         if ( !isset( $p['trxProfiler'] ) ) {
 384                                 $p['trxProfiler'] = new TransactionProfiler();
 385                         }
 386                         if ( !isset( $p['errorLogger'] ) ) {
 387                                 $p['errorLogger'] = function ( Exception $e ) {
 388                                         trigger_error( get_class( $e ) . ': ' . $e->getMessage(), E_WARNING );
 389                                 };
 390                         }
 391
 392                         $conn = new $class( $p );
 393                 } else {
 394                         $conn = null;
 395                 }
 396
 397                 return $conn;
 398         }
 399
 400         public function setLogger( LoggerInterface $logger ) {
 401                 $this->queryLogger = $logger;
 402         }
 403
 404         public function getServerInfo() {
 405                 return $this->getServerVersion();
 406         }
 407
 408         public function bufferResults( $buffer = null ) {
 409                 $res = !$this->getFlag( DBO_NOBUFFER );
 410                 if ( $buffer !== null ) {
 411                         $buffer ? $this->clearFlag( DBO_NOBUFFER ) : $this->setFlag( DBO_NOBUFFER );
 412                 }
 413
 414                 return $res;
 415         }
 416
 417         /**
 418          * Turns on (false) or off (true) the automatic generation and sending
 419          * of a "we're sorry, but there has been a database error" page on
 420          * database errors. Default is on (false). When turned off, the
 421          * code should use lastErrno() and lastError() to handle the
 422          * situation as appropriate.
 423          *
 424          * Do not use this function outside of the Database classes.
 425          *
 426          * @param null|bool $ignoreErrors
 427          * @return bool The previous value of the flag.
 428          */
 429         protected function ignoreErrors( $ignoreErrors = null ) {
 430                 $res = $this->getFlag( DBO_IGNORE );
 431                 if ( $ignoreErrors !== null ) {
 432                         $ignoreErrors ? $this->setFlag( DBO_IGNORE ) : $this->clearFlag( DBO_IGNORE );
 433                 }
 434
 435                 return $res;
 436         }
 437
 438         public function trxLevel() {
 439                 return $this->mTrxLevel;
 440         }
 441
 442         public function trxTimestamp() {
 443                 return $this->mTrxLevel ? $this->mTrxTimestamp : null;
 444         }
 445
 446         public function tablePrefix( $prefix = null ) {
 447                 $old = $this->mTablePrefix;
 448                 if ( $prefix !== null ) {
 449                         $this->mTablePrefix = $prefix;
 450                         $this->currentDomain = ( $this->mDBname != '' )
 451                                 ? new DatabaseDomain( $this->mDBname, null, $this->mTablePrefix )
 452                                 : DatabaseDomain::newUnspecified();
 453                 }
 454
 455                 return $old;
 456         }
 457
 458         public function dbSchema( $schema = null ) {
 459                 $old = $this->mSchema;
 460                 if ( $schema !== null ) {
 461                         $this->mSchema = $schema;
 462                 }
 463
 464                 return $old;
 465         }
 466
 467         public function getLBInfo( $name = null ) {
 468                 if ( is_null( $name ) ) {
 469                         return $this->mLBInfo;
 470                 } else {
 471                         if ( array_key_exists( $name, $this->mLBInfo ) ) {
 472                                 return $this->mLBInfo[$name];
 473                         } else {
 474                                 return null;
 475                         }
 476                 }
 477         }
 478
 479         public function setLBInfo( $name, $value = null ) {
 480                 if ( is_null( $value ) ) {
 481                         $this->mLBInfo = $name;
 482                 } else {
 483                         $this->mLBInfo[$name] = $value;
 484                 }
 485         }
 486
 487         public function setLazyMasterHandle( IDatabase $conn ) {
 488                 $this->lazyMasterHandle = $conn;
 489         }
 490
 491         /**
 492          * @return IDatabase|null
 493          * @see setLazyMasterHandle()
 494          * @since 1.27
 495          */
 496         public function getLazyMasterHandle() {
 497                 return $this->lazyMasterHandle;
 498         }
 499
 500         public function implicitGroupby() {
 501                 return true;
 502         }
 503
 504         public function implicitOrderby() {
 505                 return true;
 506         }
 507
 508         public function lastQuery() {
 509                 return $this->mLastQuery;
 510         }
 511
 512         public function doneWrites() {
 513                 return (bool)$this->mDoneWrites;
 514         }
 515
 516         public function lastDoneWrites() {
 517                 return $this->mDoneWrites ?: false;
 518         }
 519
 520         public function writesPending() {
 521                 return $this->mTrxLevel && $this->mTrxDoneWrites;
 522         }
 523
 524         public function writesOrCallbacksPending() {
 525                 return $this->mTrxLevel && (
 526                         $this->mTrxDoneWrites || $this->mTrxIdleCallbacks || $this->mTrxPreCommitCallbacks
 527                 );
 528         }
 529
 530         public function pendingWriteQueryDuration( $type = self::ESTIMATE_TOTAL ) {
 531                 if ( !$this->mTrxLevel ) {
 532                         return false;
 533                 } elseif ( !$this->mTrxDoneWrites ) {
 534                         return 0.0;
 535                 }
 536
 537                 switch ( $type ) {
 538                         case self::ESTIMATE_DB_APPLY:
 539                                 $this->ping( $rtt );
 540                                 $rttAdjTotal = $this->mTrxWriteAdjQueryCount * $rtt;
 541                                 $applyTime = max( $this->mTrxWriteAdjDuration - $rttAdjTotal, 0 );
 542                                 // For omitted queries, make them count as something at least
 543                                 $omitted = $this->mTrxWriteQueryCount - $this->mTrxWriteAdjQueryCount;
 544                                 $applyTime += self::TINY_WRITE_SEC * $omitted;
 545
 546                                 return $applyTime;
 547                         default: // everything
 548                                 return $this->mTrxWriteDuration;
 549                 }
 550         }
 551
 552         public function pendingWriteCallers() {
 553                 return $this->mTrxLevel ? $this->mTrxWriteCallers : [];
 554         }
 555
 556         protected function pendingWriteAndCallbackCallers() {
 557                 if ( !$this->mTrxLevel ) {
 558                         return [];
 559                 }
 560
 561                 $fnames = $this->mTrxWriteCallers;
 562                 foreach ( [
 563                         $this->mTrxIdleCallbacks,
 564                         $this->mTrxPreCommitCallbacks,
 565                         $this->mTrxEndCallbacks
 566                 ] as $callbacks ) {
 567                         foreach ( $callbacks as $callback ) {
 568                                 $fnames[] = $callback[1];
 569                         }
 570                 }
 571
 572                 return $fnames;
 573         }
 574
 575         public function isOpen() {
 576                 return $this->mOpened;
 577         }
 578
 579         public function setFlag( $flag, $remember = self::REMEMBER_NOTHING ) {
 580                 if ( $remember === self::REMEMBER_PRIOR ) {
 581                         array_push( $this->priorFlags, $this->mFlags );
 582                 }
 583                 $this->mFlags |= $flag;
 584         }
 585
 586         public function clearFlag( $flag, $remember = self::REMEMBER_NOTHING ) {
 587                 if ( $remember === self::REMEMBER_PRIOR ) {
 588                         array_push( $this->priorFlags, $this->mFlags );
 589                 }
 590                 $this->mFlags &= ~$flag;
 591         }
 592
 593         public function restoreFlags( $state = self::RESTORE_PRIOR ) {
 594                 if ( !$this->priorFlags ) {
 595                         return;
 596                 }
 597
 598                 if ( $state === self::RESTORE_INITIAL ) {
 599                         $this->mFlags = reset( $this->priorFlags );
 600                         $this->priorFlags = [];
 601                 } else {
 602                         $this->mFlags = array_pop( $this->priorFlags );
 603                 }
 604         }
 605
 606         public function getFlag( $flag ) {
 607                 return !!( $this->mFlags & $flag );
 608         }
 609
 610         public function getProperty( $name ) {
 611                 return $this->$name;
 612         }
 613
 614         public function getDomainID() {
 615                 return $this->currentDomain->getId();
 616         }
 617
 618         final public function getWikiID() {
 619                 return $this->getDomainID();
 620         }
 621
 622         /**
 623          * Get information about an index into an object
 624          * @param string $table Table name
 625          * @param string $index Index name
 626          * @param string $fname Calling function name
 627          * @return mixed Database-specific index description class or false if the index does not exist
 628          */
 629         abstract function indexInfo( $table, $index, $fname = __METHOD__ );
 630
 631         /**
 632          * Wrapper for addslashes()
 633          *
 634          * @param string $s String to be slashed.
 635          * @return string Slashed string.
 636          */
 637         abstract function strencode( $s );
 638
 639         protected function installErrorHandler() {
 640                 $this->mPHPError = false;
 641                 $this->htmlErrors = ini_set( 'html_errors', '0' );
 642                 set_error_handler( [ $this, 'connectionErrorLogger' ] );
 643         }
 644
 645         /**
 646          * @return bool|string
 647          */
 648         protected function restoreErrorHandler() {
 649                 restore_error_handler();
 650                 if ( $this->htmlErrors !== false ) {
 651                         ini_set( 'html_errors', $this->htmlErrors );
 652                 }
 653                 if ( $this->mPHPError ) {
 654                         $error = preg_replace( '!\[<a.*</a>\]!', '', $this->mPHPError );
 655                         $error = preg_replace( '!^.*?:\s?(.*)$!', '$1', $error );
 656
 657                         return $error;
 658                 } else {
 659                         return false;
 660                 }
 661         }
 662
 663         /**
 664          * This method should not be used outside of Database classes
 665          *
 666          * @param int $errno
 667          * @param string $errstr
 668          */
 669         public function connectionErrorLogger( $errno, $errstr ) {
 670                 $this->mPHPError = $errstr;
 671         }
 672
 673         /**
 674          * Create a log context to pass to PSR-3 logger functions.
 675          *
 676          * @param array $extras Additional data to add to context
 677          * @return array
 678          */
 679         protected function getLogContext( array $extras = [] ) {
 680                 return array_merge(
 681                         [
 682                                 'db_server' => $this->mServer,
 683                                 'db_name' => $this->mDBname,
 684                                 'db_user' => $this->mUser,
 685                         ],
 686                         $extras
 687                 );
 688         }
 689
 690         public function close() {
 691                 if ( $this->mConn ) {
 692                         if ( $this->trxLevel() ) {
 693                                 $this->commit( __METHOD__, self::FLUSHING_INTERNAL );
 694                         }
 695
 696                         $closed = $this->closeConnection();
 697                         $this->mConn = false;
 698                 } elseif ( $this->mTrxIdleCallbacks || $this->mTrxEndCallbacks ) { // sanity
 699                         throw new RuntimeException( "Transaction callbacks still pending." );
 700                 } else {
 701                         $closed = true;
 702                 }
 703                 $this->mOpened = false;
 704
 705                 return $closed;
 706         }
 707
 708         /**
 709          * Make sure isOpen() returns true as a sanity check
 710          *
 711          * @throws DBUnexpectedError
 712          */
 713         protected function assertOpen() {
 714                 if ( !$this->isOpen() ) {
 715                         throw new DBUnexpectedError( $this, "DB connection was already closed." );
 716                 }
 717         }
 718
 719         /**
 720          * Closes underlying database connection
 721          * @since 1.20
 722          * @return bool Whether connection was closed successfully
 723          */
 724         abstract protected function closeConnection();
 725
 726         public function reportConnectionError( $error = 'Unknown error' ) {
 727                 $myError = $this->lastError();
 728                 if ( $myError ) {
 729                         $error = $myError;
 730                 }
 731
 732                 # New method
 733                 throw new DBConnectionError( $this, $error );
 734         }
 735
 736         /**
 737          * The DBMS-dependent part of query()
 738          *
 739          * @param string $sql SQL query.
 740          * @return ResultWrapper|bool Result object to feed to fetchObject,
 741          *   fetchRow, ...; or false on failure
 742          */
 743         abstract protected function doQuery( $sql );
 744
 745         /**
 746          * Determine whether a query writes to the DB.
 747          * Should return true if unsure.
 748          *
 749          * @param string $sql
 750          * @return bool
 751          */
 752         protected function isWriteQuery( $sql ) {
 753                 return !preg_match(
 754                         '/^(?:SELECT|BEGIN|ROLLBACK|COMMIT|SET|SHOW|EXPLAIN|\(SELECT)\b/i', $sql );
 755         }
 756
 757         /**
 758          * @param $sql
 759          * @return string|null
 760          */
 761         protected function getQueryVerb( $sql ) {
 762                 return preg_match( '/^\s*([a-z]+)/i', $sql, $m ) ? strtoupper( $m[1] ) : null;
 763         }
 764
 765         /**
 766          * Determine whether a SQL statement is sensitive to isolation level.
 767          * A SQL statement is considered transactable if its result could vary
 768          * depending on the transaction isolation level. Operational commands
 769          * such as 'SET' and 'SHOW' are not considered to be transactable.
 770          *
 771          * @param string $sql
 772          * @return bool
 773          */
 774         protected function isTransactableQuery( $sql ) {
 775                 $verb = $this->getQueryVerb( $sql );
 776                 return !in_array( $verb, [ 'BEGIN', 'COMMIT', 'ROLLBACK', 'SHOW', 'SET' ], true );
 777         }
 778
 779         /**
 780          * @param string $sql A SQL query
 781          * @return bool Whether $sql is SQL for creating/dropping a new TEMPORARY table
 782          */
 783         protected function registerTempTableOperation( $sql ) {
 784                 if ( preg_match(
 785                         '/^(CREATE|DROP)\s+TEMPORARY\s+TABLE\s+(?:IF\s+NOT\s+EXISTS\s+)?[`"\']?(\w+)[`"\']?/i',
 786                         $sql,
 787                         $matches
 788                 ) ) {
 789                         list( , $verb, $table ) = $matches;
 790                         if ( $verb === 'CREATE' ) {
 791                                 $this->mSessionTempTables[$table] = 1;
 792                         } else {
 793                                 unset( $this->mSessionTempTables[$table] );
 794                         }
 795
 796                         return true;
 797                 } elseif ( preg_match(
 798                         '/^(?:INSERT\s+(?:\w+\s+)?INTO|UPDATE|DELETE\s+FROM)\s+[`"\']?(\w+)[`"\']?/i',
 799                         $sql,
 800                         $matches
 801                 ) ) {
 802                         return isset( $this->mSessionTempTables[$matches[1]] );
 803                 }
 804
 805                 return false;
 806         }
 807
 808         public function query( $sql, $fname = __METHOD__, $tempIgnore = false ) {
 809                 $priorWritesPending = $this->writesOrCallbacksPending();
 810                 $this->mLastQuery = $sql;
 811
 812                 $isWrite = $this->isWriteQuery( $sql ) && !$this->registerTempTableOperation( $sql );
 813                 if ( $isWrite ) {
 814                         $reason = $this->getReadOnlyReason();
 815                         if ( $reason !== false ) {
 816                                 throw new DBReadOnlyError( $this, "Database is read-only: $reason" );
 817                         }
 818                         # Set a flag indicating that writes have been done
 819                         $this->mDoneWrites = microtime( true );
 820                 }
 821
 822                 // Add trace comment to the begin of the sql string, right after the operator.
 823                 // Or, for one-word queries (like "BEGIN" or COMMIT") add it to the end (bug 42598)
 824                 $commentedSql = preg_replace( '/\s|$/', " /* $fname {$this->agent} */ ", $sql, 1 );
 825
 826                 # Start implicit transactions that wrap the request if DBO_TRX is enabled
 827                 if ( !$this->mTrxLevel && $this->getFlag( DBO_TRX )
 828                         && $this->isTransactableQuery( $sql )
 829                 ) {
 830                         $this->begin( __METHOD__ . " ($fname)", self::TRANSACTION_INTERNAL );
 831                         $this->mTrxAutomatic = true;
 832                 }
 833
 834                 # Keep track of whether the transaction has write queries pending
 835                 if ( $this->mTrxLevel && !$this->mTrxDoneWrites && $isWrite ) {
 836                         $this->mTrxDoneWrites = true;
 837                         $this->trxProfiler->transactionWritingIn(
 838                                 $this->mServer, $this->mDBname, $this->mTrxShortId );
 839                 }
 840
 841                 if ( $this->getFlag( DBO_DEBUG ) ) {
 842                         $this->queryLogger->debug( "{$this->mDBname} {$commentedSql}" );
 843                 }
 844
 845                 # Avoid fatals if close() was called
 846                 $this->assertOpen();
 847
 848                 # Send the query to the server
 849                 $ret = $this->doProfiledQuery( $sql, $commentedSql, $isWrite, $fname );
 850
 851                 # Try reconnecting if the connection was lost
 852                 if ( false === $ret && $this->wasErrorReissuable() ) {
 853                         $recoverable = $this->canRecoverFromDisconnect( $sql, $priorWritesPending );
 854                         # Stash the last error values before anything might clear them
 855                         $lastError = $this->lastError();
 856                         $lastErrno = $this->lastErrno();
 857                         # Update state tracking to reflect transaction loss due to disconnection
 858                         $this->handleSessionLoss();
 859                         if ( $this->reconnect() ) {
 860                                 $msg = __METHOD__ . ": lost connection to {$this->getServer()}; reconnected";
 861                                 $this->connLogger->warning( $msg );
 862                                 $this->queryLogger->warning(
 863                                         "$msg:\n" . ( new RuntimeException() )->getTraceAsString() );
 864
 865                                 if ( !$recoverable ) {
 866                                         # Callers may catch the exception and continue to use the DB
 867                                         $this->reportQueryError( $lastError, $lastErrno, $sql, $fname );
 868                                 } else {
 869                                         # Should be safe to silently retry the query
 870                                         $ret = $this->doProfiledQuery( $sql, $commentedSql, $isWrite, $fname );
 871                                 }
 872                         } else {
 873                                 $msg = __METHOD__ . ": lost connection to {$this->getServer()} permanently";
 874                                 $this->connLogger->error( $msg );
 875                         }
 876                 }
 877
 878                 if ( false === $ret ) {
 879                         # Deadlocks cause the entire transaction to abort, not just the statement.
 880                         # http://dev.mysql.com/doc/refman/5.7/en/innodb-error-handling.html
 881                         # https://www.postgresql.org/docs/9.1/static/explicit-locking.html
 882                         if ( $this->wasDeadlock() ) {
 883                                 if ( $this->explicitTrxActive() || $priorWritesPending ) {
 884                                         $tempIgnore = false; // not recoverable
 885                                 }
 886                                 # Update state tracking to reflect transaction loss
 887                                 $this->handleSessionLoss();
 888                         }
 889
 890                         $this->reportQueryError(
 891                                 $this->lastError(), $this->lastErrno(), $sql, $fname, $tempIgnore );
 892                 }
 893
 894                 $res = $this->resultObject( $ret );
 895
 896                 return $res;
 897         }
 898
 899         private function doProfiledQuery( $sql, $commentedSql, $isWrite, $fname ) {
 900                 $isMaster = !is_null( $this->getLBInfo( 'master' ) );
 901                 # generalizeSQL() will probably cut down the query to reasonable
 902                 # logging size most of the time. The substr is really just a sanity check.
 903                 if ( $isMaster ) {
 904                         $queryProf = 'query-m: ' . substr( self::generalizeSQL( $sql ), 0, 255 );
 905                 } else {
 906                         $queryProf = 'query: ' . substr( self::generalizeSQL( $sql ), 0, 255 );
 907                 }
 908
 909                 # Include query transaction state
 910                 $queryProf .= $this->mTrxShortId ? " [TRX#{$this->mTrxShortId}]" : "";
 911
 912                 $startTime = microtime( true );
 913                 if ( $this->profiler ) {
 914                         call_user_func( [ $this->profiler, 'profileIn' ], $queryProf );
 915                 }
 916                 $ret = $this->doQuery( $commentedSql );
 917                 if ( $this->profiler ) {
 918                         call_user_func( [ $this->profiler, 'profileOut' ], $queryProf );
 919                 }
 920                 $queryRuntime = max( microtime( true ) - $startTime, 0.0 );
 921
 922                 unset( $queryProfSection ); // profile out (if set)
 923
 924                 if ( $ret !== false ) {
 925                         $this->lastPing = $startTime;
 926                         if ( $isWrite && $this->mTrxLevel ) {
 927                                 $this->updateTrxWriteQueryTime( $sql, $queryRuntime );
 928                                 $this->mTrxWriteCallers[] = $fname;
 929                         }
 930                 }
 931
 932                 if ( $sql === self::PING_QUERY ) {
 933                         $this->mRTTEstimate = $queryRuntime;
 934                 }
 935
 936                 $this->trxProfiler->recordQueryCompletion(
 937                         $queryProf, $startTime, $isWrite, $this->affectedRows()
 938                 );
 939                 $this->queryLogger->debug( $sql, [
 940                         'method' => $fname,
 941                         'master' => $isMaster,
 942                         'runtime' => $queryRuntime,
 943                 ] );
 944
 945                 return $ret;
 946         }
 947
 948         /**
 949          * Update the estimated run-time of a query, not counting large row lock times
 950          *
 951          * LoadBalancer can be set to rollback transactions that will create huge replication
 952          * lag. It bases this estimate off of pendingWriteQueryDuration(). Certain simple
 953          * queries, like inserting a row can take a long time due to row locking. This method
 954          * uses some simple heuristics to discount those cases.
 955          *
 956          * @param string $sql A SQL write query
 957          * @param float $runtime Total runtime, including RTT
 958          */
 959         private function updateTrxWriteQueryTime( $sql, $runtime ) {
 960                 // Whether this is indicative of replica DB runtime (except for RBR or ws_repl)
 961                 $indicativeOfReplicaRuntime = true;
 962                 if ( $runtime > self::SLOW_WRITE_SEC ) {
 963                         $verb = $this->getQueryVerb( $sql );
 964                         // insert(), upsert(), replace() are fast unless bulky in size or blocked on locks
 965                         if ( $verb === 'INSERT' ) {
 966                                 $indicativeOfReplicaRuntime = $this->affectedRows() > self::SMALL_WRITE_ROWS;
 967                         } elseif ( $verb === 'REPLACE' ) {
 968                                 $indicativeOfReplicaRuntime = $this->affectedRows() > self::SMALL_WRITE_ROWS / 2;
 969                         }
 970                 }
 971
 972                 $this->mTrxWriteDuration += $runtime;
 973                 $this->mTrxWriteQueryCount += 1;
 974                 if ( $indicativeOfReplicaRuntime ) {
 975                         $this->mTrxWriteAdjDuration += $runtime;
 976                         $this->mTrxWriteAdjQueryCount += 1;
 977                 }
 978         }
 979
 980         private function canRecoverFromDisconnect( $sql, $priorWritesPending ) {
 981                 # Transaction dropped; this can mean lost writes, or REPEATABLE-READ snapshots.
 982                 # Dropped connections also mean that named locks are automatically released.
 983                 # Only allow error suppression in autocommit mode or when the lost transaction
 984                 # didn't matter anyway (aside from DBO_TRX snapshot loss).
 985                 if ( $this->mNamedLocksHeld ) {
 986                         return false; // possible critical section violation
 987                 } elseif ( $sql === 'COMMIT' ) {
 988                         return !$priorWritesPending; // nothing written anyway? (T127428)
 989                 } elseif ( $sql === 'ROLLBACK' ) {
 990                         return true; // transaction lost...which is also what was requested :)
 991                 } elseif ( $this->explicitTrxActive() ) {
 992                         return false; // don't drop atomocity
 993                 } elseif ( $priorWritesPending ) {
 994                         return false; // prior writes lost from implicit transaction
 995                 }
 996
 997                 return true;
 998         }
 999
1000         private function handleSessionLoss() {
1001                 $this->mTrxLevel = 0;
1002                 $this->mTrxIdleCallbacks = []; // bug 65263
1003                 $this->mTrxPreCommitCallbacks = []; // bug 65263
1004                 $this->mSessionTempTables = [];
1005                 $this->mNamedLocksHeld = [];
1006                 try {
1007                         // Handle callbacks in mTrxEndCallbacks
1008                         $this->runOnTransactionIdleCallbacks( self::TRIGGER_ROLLBACK );
1009                         $this->runTransactionListenerCallbacks( self::TRIGGER_ROLLBACK );
1010                         return null;
1011                 } catch ( Exception $e ) {
1012                         // Already logged; move on...
1013                         return $e;
1014                 }
1015         }
1016
1017         public function reportQueryError( $error, $errno, $sql, $fname, $tempIgnore = false ) {
1018                 if ( $this->ignoreErrors() || $tempIgnore ) {
1019                         $this->queryLogger->debug( "SQL ERROR (ignored): $error\n" );
1020                 } else {
1021                         $sql1line = mb_substr( str_replace( "\n", "\\n", $sql ), 0, 5 * 1024 );
1022                         $this->queryLogger->error(
1023                                 "{fname}\t{db_server}\t{errno}\t{error}\t{sql1line}",
1024                                 $this->getLogContext( [
1025                                         'method' => __METHOD__,
1026                                         'errno' => $errno,
1027                                         'error' => $error,
1028                                         'sql1line' => $sql1line,
1029                                         'fname' => $fname,
1030                                 ] )
1031                         );
1032                         $this->queryLogger->debug( "SQL ERROR: " . $error . "\n" );
1033                         throw new DBQueryError( $this, $error, $errno, $sql, $fname );
1034                 }
1035         }
1036
1037         public function freeResult( $res ) {
1038         }
1039
1040         public function selectField(
1041                 $table, $var, $cond = '', $fname = __METHOD__, $options = []
1042         ) {
1043                 if ( $var === '*' ) { // sanity
1044                         throw new DBUnexpectedError( $this, "Cannot use a * field: got '$var'" );
1045                 }
1046
1047                 if ( !is_array( $options ) ) {
1048                         $options = [ $options ];
1049                 }
1050
1051                 $options['LIMIT'] = 1;
1052
1053                 $res = $this->select( $table, $var, $cond, $fname, $options );
1054                 if ( $res === false || !$this->numRows( $res ) ) {
1055                         return false;
1056                 }
1057
1058                 $row = $this->fetchRow( $res );
1059
1060                 if ( $row !== false ) {
1061                         return reset( $row );
1062                 } else {
1063                         return false;
1064                 }
1065         }
1066
1067         public function selectFieldValues(
1068                 $table, $var, $cond = '', $fname = __METHOD__, $options = [], $join_conds = []
1069         ) {
1070                 if ( $var === '*' ) { // sanity
1071                         throw new DBUnexpectedError( $this, "Cannot use a * field" );
1072                 } elseif ( !is_string( $var ) ) { // sanity
1073                         throw new DBUnexpectedError( $this, "Cannot use an array of fields" );
1074                 }
1075
1076                 if ( !is_array( $options ) ) {
1077                         $options = [ $options ];
1078                 }
1079
1080                 $res = $this->select( $table, $var, $cond, $fname, $options, $join_conds );
1081                 if ( $res === false ) {
1082                         return false;
1083                 }
1084
1085                 $values = [];
1086                 foreach ( $res as $row ) {
1087                         $values[] = $row->$var;
1088                 }
1089
1090                 return $values;
1091         }
1092
1093         /**
1094          * Returns an optional USE INDEX clause to go after the table, and a
1095          * string to go at the end of the query.
1096          *
1097          * @param array $options Associative array of options to be turned into
1098          *   an SQL query, valid keys are listed in the function.
1099          * @return array
1100          * @see DatabaseBase::select()
1101          */
1102         protected function makeSelectOptions( $options ) {
1103                 $preLimitTail = $postLimitTail = '';
1104                 $startOpts = '';
1105
1106                 $noKeyOptions = [];
1107
1108                 foreach ( $options as $key => $option ) {
1109                         if ( is_numeric( $key ) ) {
1110                                 $noKeyOptions[$option] = true;
1111                         }
1112                 }
1113
1114                 $preLimitTail .= $this->makeGroupByWithHaving( $options );
1115
1116                 $preLimitTail .= $this->makeOrderBy( $options );
1117
1118                 // if (isset($options['LIMIT'])) {
1119                 //      $tailOpts .= $this->limitResult('', $options['LIMIT'],
1120                 //              isset($options['OFFSET']) ? $options['OFFSET']
1121                 //              : false);
1122                 // }
1123
1124                 if ( isset( $noKeyOptions['FOR UPDATE'] ) ) {
1125                         $postLimitTail .= ' FOR UPDATE';
1126                 }
1127
1128                 if ( isset( $noKeyOptions['LOCK IN SHARE MODE'] ) ) {
1129                         $postLimitTail .= ' LOCK IN SHARE MODE';
1130                 }
1131
1132                 if ( isset( $noKeyOptions['DISTINCT'] ) || isset( $noKeyOptions['DISTINCTROW'] ) ) {
1133                         $startOpts .= 'DISTINCT';
1134                 }
1135
1136                 # Various MySQL extensions
1137                 if ( isset( $noKeyOptions['STRAIGHT_JOIN'] ) ) {
1138                         $startOpts .= ' /*! STRAIGHT_JOIN */';
1139                 }
1140
1141                 if ( isset( $noKeyOptions['HIGH_PRIORITY'] ) ) {
1142                         $startOpts .= ' HIGH_PRIORITY';
1143                 }
1144
1145                 if ( isset( $noKeyOptions['SQL_BIG_RESULT'] ) ) {
1146                         $startOpts .= ' SQL_BIG_RESULT';
1147                 }
1148
1149                 if ( isset( $noKeyOptions['SQL_BUFFER_RESULT'] ) ) {
1150                         $startOpts .= ' SQL_BUFFER_RESULT';
1151                 }
1152
1153                 if ( isset( $noKeyOptions['SQL_SMALL_RESULT'] ) ) {
1154                         $startOpts .= ' SQL_SMALL_RESULT';
1155                 }
1156
1157                 if ( isset( $noKeyOptions['SQL_CALC_FOUND_ROWS'] ) ) {
1158                         $startOpts .= ' SQL_CALC_FOUND_ROWS';
1159                 }
1160
1161                 if ( isset( $noKeyOptions['SQL_CACHE'] ) ) {
1162                         $startOpts .= ' SQL_CACHE';
1163                 }
1164
1165                 if ( isset( $noKeyOptions['SQL_NO_CACHE'] ) ) {
1166                         $startOpts .= ' SQL_NO_CACHE';
1167                 }
1168
1169                 if ( isset( $options['USE INDEX'] ) && is_string( $options['USE INDEX'] ) ) {
1170                         $useIndex = $this->useIndexClause( $options['USE INDEX'] );
1171                 } else {
1172                         $useIndex = '';
1173                 }
1174                 if ( isset( $options['IGNORE INDEX'] ) && is_string( $options['IGNORE INDEX'] ) ) {
1175                         $ignoreIndex = $this->ignoreIndexClause( $options['IGNORE INDEX'] );
1176                 } else {
1177                         $ignoreIndex = '';
1178                 }
1179
1180                 return [ $startOpts, $useIndex, $preLimitTail, $postLimitTail, $ignoreIndex ];
1181         }
1182
1183         /**
1184          * Returns an optional GROUP BY with an optional HAVING
1185          *
1186          * @param array $options Associative array of options
1187          * @return string
1188          * @see DatabaseBase::select()
1189          * @since 1.21
1190          */
1191         protected function makeGroupByWithHaving( $options ) {
1192                 $sql = '';
1193                 if ( isset( $options['GROUP BY'] ) ) {
1194                         $gb = is_array( $options['GROUP BY'] )
1195                                 ? implode( ',', $options['GROUP BY'] )
1196                                 : $options['GROUP BY'];
1197                         $sql .= ' GROUP BY ' . $gb;
1198                 }
1199                 if ( isset( $options['HAVING'] ) ) {
1200                         $having = is_array( $options['HAVING'] )
1201                                 ? $this->makeList( $options['HAVING'], self::LIST_AND )
1202                                 : $options['HAVING'];
1203                         $sql .= ' HAVING ' . $having;
1204                 }
1205
1206                 return $sql;
1207         }
1208
1209         /**
1210          * Returns an optional ORDER BY
1211          *
1212          * @param array $options Associative array of options
1213          * @return string
1214          * @see DatabaseBase::select()
1215          * @since 1.21
1216          */
1217         protected function makeOrderBy( $options ) {
1218                 if ( isset( $options['ORDER BY'] ) ) {
1219                         $ob = is_array( $options['ORDER BY'] )
1220                                 ? implode( ',', $options['ORDER BY'] )
1221                                 : $options['ORDER BY'];
1222
1223                         return ' ORDER BY ' . $ob;
1224                 }
1225
1226                 return '';
1227         }
1228
1229         // See IDatabase::select for the docs for this function
1230         public function select( $table, $vars, $conds = '', $fname = __METHOD__,
1231                 $options = [], $join_conds = [] ) {
1232                 $sql = $this->selectSQLText( $table, $vars, $conds, $fname, $options, $join_conds );
1233
1234                 return $this->query( $sql, $fname );
1235         }
1236
1237         public function selectSQLText( $table, $vars, $conds = '', $fname = __METHOD__,
1238                 $options = [], $join_conds = []
1239         ) {
1240                 if ( is_array( $vars ) ) {
1241                         $vars = implode( ',', $this->fieldNamesWithAlias( $vars ) );
1242                 }
1243
1244                 $options = (array)$options;
1245                 $useIndexes = ( isset( $options['USE INDEX'] ) && is_array( $options['USE INDEX'] ) )
1246                         ? $options['USE INDEX']
1247                         : [];
1248                 $ignoreIndexes = ( isset( $options['IGNORE INDEX'] ) && is_array( $options['IGNORE INDEX'] ) )
1249                         ? $options['IGNORE INDEX']
1250                         : [];
1251
1252                 if ( is_array( $table ) ) {
1253                         $from = ' FROM ' .
1254                                 $this->tableNamesWithIndexClauseOrJOIN( $table, $useIndexes, $ignoreIndexes, $join_conds );
1255                 } elseif ( $table != '' ) {
1256                         if ( $table[0] == ' ' ) {
1257                                 $from = ' FROM ' . $table;
1258                         } else {
1259                                 $from = ' FROM ' .
1260                                         $this->tableNamesWithIndexClauseOrJOIN( [ $table ], $useIndexes, $ignoreIndexes, [] );
1261                         }
1262                 } else {
1263                         $from = '';
1264                 }
1265
1266                 list( $startOpts, $useIndex, $preLimitTail, $postLimitTail, $ignoreIndex ) =
1267                         $this->makeSelectOptions( $options );
1268
1269                 if ( !empty( $conds ) ) {
1270                         if ( is_array( $conds ) ) {
1271                                 $conds = $this->makeList( $conds, self::LIST_AND );
1272                         }
1273                         $sql = "SELECT $startOpts $vars $from $useIndex $ignoreIndex WHERE $conds $preLimitTail";
1274                 } else {
1275                         $sql = "SELECT $startOpts $vars $from $useIndex $ignoreIndex $preLimitTail";
1276                 }
1277
1278                 if ( isset( $options['LIMIT'] ) ) {
1279                         $sql = $this->limitResult( $sql, $options['LIMIT'],
1280                                 isset( $options['OFFSET'] ) ? $options['OFFSET'] : false );
1281                 }
1282                 $sql = "$sql $postLimitTail";
1283
1284                 if ( isset( $options['EXPLAIN'] ) ) {
1285                         $sql = 'EXPLAIN ' . $sql;
1286                 }
1287
1288                 return $sql;
1289         }
1290
1291         public function selectRow( $table, $vars, $conds, $fname = __METHOD__,
1292                 $options = [], $join_conds = []
1293         ) {
1294                 $options = (array)$options;
1295                 $options['LIMIT'] = 1;
1296                 $res = $this->select( $table, $vars, $conds, $fname, $options, $join_conds );
1297
1298                 if ( $res === false ) {
1299                         return false;
1300                 }
1301
1302                 if ( !$this->numRows( $res ) ) {
1303                         return false;
1304                 }
1305
1306                 $obj = $this->fetchObject( $res );
1307
1308                 return $obj;
1309         }
1310
1311         public function estimateRowCount(
1312                 $table, $vars = '*', $conds = '', $fname = __METHOD__, $options = []
1313         ) {
1314                 $rows = 0;
1315                 $res = $this->select( $table, [ 'rowcount' => 'COUNT(*)' ], $conds, $fname, $options );
1316
1317                 if ( $res ) {
1318                         $row = $this->fetchRow( $res );
1319                         $rows = ( isset( $row['rowcount'] ) ) ? (int)$row['rowcount'] : 0;
1320                 }
1321
1322                 return $rows;
1323         }
1324
1325         public function selectRowCount(
1326                 $tables, $vars = '*', $conds = '', $fname = __METHOD__, $options = [], $join_conds = []
1327         ) {
1328                 $rows = 0;
1329                 $sql = $this->selectSQLText( $tables, '1', $conds, $fname, $options, $join_conds );
1330                 $res = $this->query( "SELECT COUNT(*) AS rowcount FROM ($sql) tmp_count", $fname );
1331
1332                 if ( $res ) {
1333                         $row = $this->fetchRow( $res );
1334                         $rows = ( isset( $row['rowcount'] ) ) ? (int)$row['rowcount'] : 0;
1335                 }
1336
1337                 return $rows;
1338         }
1339
1340         /**
1341          * Removes most variables from an SQL query and replaces them with X or N for numbers.
1342          * It's only slightly flawed. Don't use for anything important.
1343          *
1344          * @param string $sql A SQL Query
1345          *
1346          * @return string
1347          */
1348         protected static function generalizeSQL( $sql ) {
1349                 # This does the same as the regexp below would do, but in such a way
1350                 # as to avoid crashing php on some large strings.
1351                 # $sql = preg_replace( "/'([^\\\\']|\\\\.)*'|\"([^\\\\\"]|\\\\.)*\"/", "'X'", $sql );
1352
1353                 $sql = str_replace( "\\\\", '', $sql );
1354                 $sql = str_replace( "\\'", '', $sql );
1355                 $sql = str_replace( "\\\"", '', $sql );
1356                 $sql = preg_replace( "/'.*'/s", "'X'", $sql );
1357                 $sql = preg_replace( '/".*"/s', "'X'", $sql );
1358
1359                 # All newlines, tabs, etc replaced by single space
1360                 $sql = preg_replace( '/\s+/', ' ', $sql );
1361
1362                 # All numbers => N,
1363                 # except the ones surrounded by characters, e.g. l10n
1364                 $sql = preg_replace( '/-?\d+(,-?\d+)+/s', 'N,...,N', $sql );
1365                 $sql = preg_replace( '/(?<![a-zA-Z])-?\d+(?![a-zA-Z])/s', 'N', $sql );
1366
1367                 return $sql;
1368         }
1369
1370         public function fieldExists( $table, $field, $fname = __METHOD__ ) {
1371                 $info = $this->fieldInfo( $table, $field );
1372
1373                 return (bool)$info;
1374         }
1375
1376         public function indexExists( $table, $index, $fname = __METHOD__ ) {
1377                 if ( !$this->tableExists( $table ) ) {
1378                         return null;
1379                 }
1380
1381                 $info = $this->indexInfo( $table, $index, $fname );
1382                 if ( is_null( $info ) ) {
1383                         return null;
1384                 } else {
1385                         return $info !== false;
1386                 }
1387         }
1388
1389         public function tableExists( $table, $fname = __METHOD__ ) {
1390                 $table = $this->tableName( $table );
1391                 $old = $this->ignoreErrors( true );
1392                 $res = $this->query( "SELECT 1 FROM $table LIMIT 1", $fname );
1393                 $this->ignoreErrors( $old );
1394
1395                 return (bool)$res;
1396         }
1397
1398         public function indexUnique( $table, $index ) {
1399                 $indexInfo = $this->indexInfo( $table, $index );
1400
1401                 if ( !$indexInfo ) {
1402                         return null;
1403                 }
1404
1405                 return !$indexInfo[0]->Non_unique;
1406         }
1407
1408         /**
1409          * Helper for DatabaseBase::insert().
1410          *
1411          * @param array $options
1412          * @return string
1413          */
1414         protected function makeInsertOptions( $options ) {
1415                 return implode( ' ', $options );
1416         }
1417
1418         public function insert( $table, $a, $fname = __METHOD__, $options = [] ) {
1419                 # No rows to insert, easy just return now
1420                 if ( !count( $a ) ) {
1421                         return true;
1422                 }
1423
1424                 $table = $this->tableName( $table );
1425
1426                 if ( !is_array( $options ) ) {
1427                         $options = [ $options ];
1428                 }
1429
1430                 $fh = null;
1431                 if ( isset( $options['fileHandle'] ) ) {
1432                         $fh = $options['fileHandle'];
1433                 }
1434                 $options = $this->makeInsertOptions( $options );
1435
1436                 if ( isset( $a[0] ) && is_array( $a[0] ) ) {
1437                         $multi = true;
1438                         $keys = array_keys( $a[0] );
1439                 } else {
1440                         $multi = false;
1441                         $keys = array_keys( $a );
1442                 }
1443
1444                 $sql = 'INSERT ' . $options .
1445                         " INTO $table (" . implode( ',', $keys ) . ') VALUES ';
1446
1447                 if ( $multi ) {
1448                         $first = true;
1449                         foreach ( $a as $row ) {
1450                                 if ( $first ) {
1451                                         $first = false;
1452                                 } else {
1453                                         $sql .= ',';
1454                                 }
1455                                 $sql .= '(' . $this->makeList( $row ) . ')';
1456                         }
1457                 } else {
1458                         $sql .= '(' . $this->makeList( $a ) . ')';
1459                 }
1460
1461                 if ( $fh !== null && false === fwrite( $fh, $sql ) ) {
1462                         return false;
1463                 } elseif ( $fh !== null ) {
1464                         return true;
1465                 }
1466
1467                 return (bool)$this->query( $sql, $fname );
1468         }
1469
1470         /**
1471          * Make UPDATE options array for DatabaseBase::makeUpdateOptions
1472          *
1473          * @param array $options
1474          * @return array
1475          */
1476         protected function makeUpdateOptionsArray( $options ) {
1477                 if ( !is_array( $options ) ) {
1478                         $options = [ $options ];
1479                 }
1480
1481                 $opts = [];
1482
1483                 if ( in_array( 'IGNORE', $options ) ) {
1484                         $opts[] = 'IGNORE';
1485                 }
1486
1487                 return $opts;
1488         }
1489
1490         /**
1491          * Make UPDATE options for the DatabaseBase::update function
1492          *
1493          * @param array $options The options passed to DatabaseBase::update
1494          * @return string
1495          */
1496         protected function makeUpdateOptions( $options ) {
1497                 $opts = $this->makeUpdateOptionsArray( $options );
1498
1499                 return implode( ' ', $opts );
1500         }
1501
1502         public function update( $table, $values, $conds, $fname = __METHOD__, $options = [] ) {
1503                 $table = $this->tableName( $table );
1504                 $opts = $this->makeUpdateOptions( $options );
1505                 $sql = "UPDATE $opts $table SET " . $this->makeList( $values, self::LIST_SET );
1506
1507                 if ( $conds !== [] && $conds !== '*' ) {
1508                         $sql .= " WHERE " . $this->makeList( $conds, self::LIST_AND );
1509                 }
1510
1511                 return $this->query( $sql, $fname );
1512         }
1513
1514         public function makeList( $a, $mode = self::LIST_COMMA ) {
1515                 if ( !is_array( $a ) ) {
1516                         throw new DBUnexpectedError( $this, __METHOD__ . ' called with incorrect parameters' );
1517                 }
1518
1519                 $first = true;
1520                 $list = '';
1521
1522                 foreach ( $a as $field => $value ) {
1523                         if ( !$first ) {
1524                                 if ( $mode == self::LIST_AND ) {
1525                                         $list .= ' AND ';
1526                                 } elseif ( $mode == self::LIST_OR ) {
1527                                         $list .= ' OR ';
1528                                 } else {
1529                                         $list .= ',';
1530                                 }
1531                         } else {
1532                                 $first = false;
1533                         }
1534
1535                         if ( ( $mode == self::LIST_AND || $mode == self::LIST_OR ) && is_numeric( $field ) ) {
1536                                 $list .= "($value)";
1537                         } elseif ( $mode == self::LIST_SET && is_numeric( $field ) ) {
1538                                 $list .= "$value";
1539                         } elseif (
1540                                 ( $mode == self::LIST_AND || $mode == self::LIST_OR ) && is_array( $value )
1541                         ) {
1542                                 // Remove null from array to be handled separately if found
1543                                 $includeNull = false;
1544                                 foreach ( array_keys( $value, null, true ) as $nullKey ) {
1545                                         $includeNull = true;
1546                                         unset( $value[$nullKey] );
1547                                 }
1548                                 if ( count( $value ) == 0 && !$includeNull ) {
1549                                         throw new InvalidArgumentException(
1550                                                 __METHOD__ . ": empty input for field $field" );
1551                                 } elseif ( count( $value ) == 0 ) {
1552                                         // only check if $field is null
1553                                         $list .= "$field IS NULL";
1554                                 } else {
1555                                         // IN clause contains at least one valid element
1556                                         if ( $includeNull ) {
1557                                                 // Group subconditions to ensure correct precedence
1558                                                 $list .= '(';
1559                                         }
1560                                         if ( count( $value ) == 1 ) {
1561                                                 // Special-case single values, as IN isn't terribly efficient
1562                                                 // Don't necessarily assume the single key is 0; we don't
1563                                                 // enforce linear numeric ordering on other arrays here.
1564                                                 $value = array_values( $value )[0];
1565                                                 $list .= $field . " = " . $this->addQuotes( $value );
1566                                         } else {
1567                                                 $list .= $field . " IN (" . $this->makeList( $value ) . ") ";
1568                                         }
1569                                         // if null present in array, append IS NULL
1570                                         if ( $includeNull ) {
1571                                                 $list .= " OR $field IS NULL)";
1572                                         }
1573                                 }
1574                         } elseif ( $value === null ) {
1575                                 if ( $mode == self::LIST_AND || $mode == self::LIST_OR ) {
1576                                         $list .= "$field IS ";
1577                                 } elseif ( $mode == self::LIST_SET ) {
1578                                         $list .= "$field = ";
1579                                 }
1580                                 $list .= 'NULL';
1581                         } else {
1582                                 if (
1583                                         $mode == self::LIST_AND || $mode == self::LIST_OR || $mode == self::LIST_SET
1584                                 ) {
1585                                         $list .= "$field = ";
1586                                 }
1587                                 $list .= $mode == self::LIST_NAMES ? $value : $this->addQuotes( $value );
1588                         }
1589                 }
1590
1591                 return $list;
1592         }
1593
1594         public function makeWhereFrom2d( $data, $baseKey, $subKey ) {
1595                 $conds = [];
1596
1597                 foreach ( $data as $base => $sub ) {
1598                         if ( count( $sub ) ) {
1599                                 $conds[] = $this->makeList(
1600                                         [ $baseKey => $base, $subKey => array_keys( $sub ) ],
1601                                         self::LIST_AND );
1602                         }
1603                 }
1604
1605                 if ( $conds ) {
1606                         return $this->makeList( $conds, self::LIST_OR );
1607                 } else {
1608                         // Nothing to search for...
1609                         return false;
1610                 }
1611         }
1612
1613         public function aggregateValue( $valuedata, $valuename = 'value' ) {
1614                 return $valuename;
1615         }
1616
1617         public function bitNot( $field ) {
1618                 return "(~$field)";
1619         }
1620
1621         public function bitAnd( $fieldLeft, $fieldRight ) {
1622                 return "($fieldLeft & $fieldRight)";
1623         }
1624
1625         public function bitOr( $fieldLeft, $fieldRight ) {
1626                 return "($fieldLeft | $fieldRight)";
1627         }
1628
1629         public function buildConcat( $stringList ) {
1630                 return 'CONCAT(' . implode( ',', $stringList ) . ')';
1631         }
1632
1633         public function buildGroupConcatField(
1634                 $delim, $table, $field, $conds = '', $join_conds = []
1635         ) {
1636                 $fld = "GROUP_CONCAT($field SEPARATOR " . $this->addQuotes( $delim ) . ')';
1637
1638                 return '(' . $this->selectSQLText( $table, $fld, $conds, null, [], $join_conds ) . ')';
1639         }
1640
1641         public function buildStringCast( $field ) {
1642                 return $field;
1643         }
1644
1645         public function selectDB( $db ) {
1646                 # Stub. Shouldn't cause serious problems if it's not overridden, but
1647                 # if your database engine supports a concept similar to MySQL's
1648                 # databases you may as well.
1649                 $this->mDBname = $db;
1650
1651                 return true;
1652         }
1653
1654         public function getDBname() {
1655                 return $this->mDBname;
1656         }
1657
1658         public function getServer() {
1659                 return $this->mServer;
1660         }
1661
1662         /**
1663          * Format a table name ready for use in constructing an SQL query
1664          *
1665          * This does two important things: it quotes the table names to clean them up,
1666          * and it adds a table prefix if only given a table name with no quotes.
1667          *
1668          * All functions of this object which require a table name call this function
1669          * themselves. Pass the canonical name to such functions. This is only needed
1670          * when calling query() directly.
1671          *
1672          * @note This function does not sanitize user input. It is not safe to use
1673          *   this function to escape user input.
1674          * @param string $name Database table name
1675          * @param string $format One of:
1676          *   quoted - Automatically pass the table name through addIdentifierQuotes()
1677          *            so that it can be used in a query.
1678          *   raw - Do not add identifier quotes to the table name
1679          * @return string Full database name
1680          */
1681         public function tableName( $name, $format = 'quoted' ) {
1682                 # Skip the entire process when we have a string quoted on both ends.
1683                 # Note that we check the end so that we will still quote any use of
1684                 # use of `database`.table. But won't break things if someone wants
1685                 # to query a database table with a dot in the name.
1686                 if ( $this->isQuotedIdentifier( $name ) ) {
1687                         return $name;
1688                 }
1689
1690                 # Lets test for any bits of text that should never show up in a table
1691                 # name. Basically anything like JOIN or ON which are actually part of
1692                 # SQL queries, but may end up inside of the table value to combine
1693                 # sql. Such as how the API is doing.
1694                 # Note that we use a whitespace test rather than a \b test to avoid
1695                 # any remote case where a word like on may be inside of a table name
1696                 # surrounded by symbols which may be considered word breaks.
1697                 if ( preg_match( '/(^|\s)(DISTINCT|JOIN|ON|AS)(\s|$)/i', $name ) !== 0 ) {
1698                         return $name;
1699                 }
1700
1701                 # Split database and table into proper variables.
1702                 # We reverse the explode so that database.table and table both output
1703                 # the correct table.
1704                 $dbDetails = explode( '.', $name, 3 );
1705                 if ( count( $dbDetails ) == 3 ) {
1706                         list( $database, $schema, $table ) = $dbDetails;
1707                         # We don't want any prefix added in this case
1708                         $prefix = '';
1709                 } elseif ( count( $dbDetails ) == 2 ) {
1710                         list( $database, $table ) = $dbDetails;
1711                         # We don't want any prefix added in this case
1712                         # In dbs that support it, $database may actually be the schema
1713                         # but that doesn't affect any of the functionality here
1714                         $prefix = '';
1715                         $schema = '';
1716                 } else {
1717                         list( $table ) = $dbDetails;
1718                         if ( isset( $this->tableAliases[$table] ) ) {
1719                                 $database = $this->tableAliases[$table]['dbname'];
1720                                 $schema = is_string( $this->tableAliases[$table]['schema'] )
1721                                         ? $this->tableAliases[$table]['schema']
1722                                         : $this->mSchema;
1723                                 $prefix = is_string( $this->tableAliases[$table]['prefix'] )
1724                                         ? $this->tableAliases[$table]['prefix']
1725                                         : $this->mTablePrefix;
1726                         } else {
1727                                 $database = '';
1728                                 $schema = $this->mSchema; # Default schema
1729                                 $prefix = $this->mTablePrefix; # Default prefix
1730                         }
1731                 }
1732
1733                 # Quote $table and apply the prefix if not quoted.
1734                 # $tableName might be empty if this is called from Database::replaceVars()
1735                 $tableName = "{$prefix}{$table}";
1736                 if ( $format == 'quoted'
1737                         && !$this->isQuotedIdentifier( $tableName ) && $tableName !== ''
1738                 ) {
1739                         $tableName = $this->addIdentifierQuotes( $tableName );
1740                 }
1741
1742                 # Quote $schema and merge it with the table name if needed
1743                 if ( strlen( $schema ) ) {
1744                         if ( $format == 'quoted' && !$this->isQuotedIdentifier( $schema ) ) {
1745                                 $schema = $this->addIdentifierQuotes( $schema );
1746                         }
1747                         $tableName = $schema . '.' . $tableName;
1748                 }
1749
1750                 # Quote $database and merge it with the table name if needed
1751                 if ( $database !== '' ) {
1752                         if ( $format == 'quoted' && !$this->isQuotedIdentifier( $database ) ) {
1753                                 $database = $this->addIdentifierQuotes( $database );
1754                         }
1755                         $tableName = $database . '.' . $tableName;
1756                 }
1757
1758                 return $tableName;
1759         }
1760
1761         /**
1762          * Fetch a number of table names into an array
1763          * This is handy when you need to construct SQL for joins
1764          *
1765          * Example:
1766          * extract( $dbr->tableNames( 'user', 'watchlist' ) );
1767          * $sql = "SELECT wl_namespace,wl_title FROM $watchlist,$user
1768          *         WHERE wl_user=user_id AND wl_user=$nameWithQuotes";
1769          *
1770          * @return array
1771          */
1772         public function tableNames() {
1773                 $inArray = func_get_args();
1774                 $retVal = [];
1775
1776                 foreach ( $inArray as $name ) {
1777                         $retVal[$name] = $this->tableName( $name );
1778                 }
1779
1780                 return $retVal;
1781         }
1782
1783         /**
1784          * Fetch a number of table names into an zero-indexed numerical array
1785          * This is handy when you need to construct SQL for joins
1786          *
1787          * Example:
1788          * list( $user, $watchlist ) = $dbr->tableNamesN( 'user', 'watchlist' );
1789          * $sql = "SELECT wl_namespace,wl_title FROM $watchlist,$user
1790          *         WHERE wl_user=user_id AND wl_user=$nameWithQuotes";
1791          *
1792          * @return array
1793          */
1794         public function tableNamesN() {
1795                 $inArray = func_get_args();
1796                 $retVal = [];
1797
1798                 foreach ( $inArray as $name ) {
1799                         $retVal[] = $this->tableName( $name );
1800                 }
1801
1802                 return $retVal;
1803         }
1804
1805         /**
1806          * Get an aliased table name
1807          * e.g. tableName AS newTableName
1808          *
1809          * @param string $name Table name, see tableName()
1810          * @param string|bool $alias Alias (optional)
1811          * @return string SQL name for aliased table. Will not alias a table to its own name
1812          */
1813         protected function tableNameWithAlias( $name, $alias = false ) {
1814                 if ( !$alias || $alias == $name ) {
1815                         return $this->tableName( $name );
1816                 } else {
1817                         return $this->tableName( $name ) . ' ' . $this->addIdentifierQuotes( $alias );
1818                 }
1819         }
1820
1821         /**
1822          * Gets an array of aliased table names
1823          *
1824          * @param array $tables [ [alias] => table ]
1825          * @return string[] See tableNameWithAlias()
1826          */
1827         protected function tableNamesWithAlias( $tables ) {
1828                 $retval = [];
1829                 foreach ( $tables as $alias => $table ) {
1830                         if ( is_numeric( $alias ) ) {
1831                                 $alias = $table;
1832                         }
1833                         $retval[] = $this->tableNameWithAlias( $table, $alias );
1834                 }
1835
1836                 return $retval;
1837         }
1838
1839         /**
1840          * Get an aliased field name
1841          * e.g. fieldName AS newFieldName
1842          *
1843          * @param string $name Field name
1844          * @param string|bool $alias Alias (optional)
1845          * @return string SQL name for aliased field. Will not alias a field to its own name
1846          */
1847         protected function fieldNameWithAlias( $name, $alias = false ) {
1848                 if ( !$alias || (string)$alias === (string)$name ) {
1849                         return $name;
1850                 } else {
1851                         return $name . ' AS ' . $this->addIdentifierQuotes( $alias ); // PostgreSQL needs AS
1852                 }
1853         }
1854
1855         /**
1856          * Gets an array of aliased field names
1857          *
1858          * @param array $fields [ [alias] => field ]
1859          * @return string[] See fieldNameWithAlias()
1860          */
1861         protected function fieldNamesWithAlias( $fields ) {
1862                 $retval = [];
1863                 foreach ( $fields as $alias => $field ) {
1864                         if ( is_numeric( $alias ) ) {
1865                                 $alias = $field;
1866                         }
1867                         $retval[] = $this->fieldNameWithAlias( $field, $alias );
1868                 }
1869
1870                 return $retval;
1871         }
1872
1873         /**
1874          * Get the aliased table name clause for a FROM clause
1875          * which might have a JOIN and/or USE INDEX or IGNORE INDEX clause
1876          *
1877          * @param array $tables ( [alias] => table )
1878          * @param array $use_index Same as for select()
1879          * @param array $ignore_index Same as for select()
1880          * @param array $join_conds Same as for select()
1881          * @return string
1882          */
1883         protected function tableNamesWithIndexClauseOrJOIN(
1884                 $tables, $use_index = [], $ignore_index = [], $join_conds = []
1885         ) {
1886                 $ret = [];
1887                 $retJOIN = [];
1888                 $use_index = (array)$use_index;
1889                 $ignore_index = (array)$ignore_index;
1890                 $join_conds = (array)$join_conds;
1891
1892                 foreach ( $tables as $alias => $table ) {
1893                         if ( !is_string( $alias ) ) {
1894                                 // No alias? Set it equal to the table name
1895                                 $alias = $table;
1896                         }
1897                         // Is there a JOIN clause for this table?
1898                         if ( isset( $join_conds[$alias] ) ) {
1899                                 list( $joinType, $conds ) = $join_conds[$alias];
1900                                 $tableClause = $joinType;
1901                                 $tableClause .= ' ' . $this->tableNameWithAlias( $table, $alias );
1902                                 if ( isset( $use_index[$alias] ) ) { // has USE INDEX?
1903                                         $use = $this->useIndexClause( implode( ',', (array)$use_index[$alias] ) );
1904                                         if ( $use != '' ) {
1905                                                 $tableClause .= ' ' . $use;
1906                                         }
1907                                 }
1908                                 if ( isset( $ignore_index[$alias] ) ) { // has IGNORE INDEX?
1909                                         $ignore = $this->ignoreIndexClause( implode( ',', (array)$ignore_index[$alias] ) );
1910                                         if ( $ignore != '' ) {
1911                                                 $tableClause .= ' ' . $ignore;
1912                                         }
1913                                 }
1914                                 $on = $this->makeList( (array)$conds, self::LIST_AND );
1915                                 if ( $on != '' ) {
1916                                         $tableClause .= ' ON (' . $on . ')';
1917                                 }
1918
1919                                 $retJOIN[] = $tableClause;
1920                         } elseif ( isset( $use_index[$alias] ) ) {
1921                                 // Is there an INDEX clause for this table?
1922                                 $tableClause = $this->tableNameWithAlias( $table, $alias );
1923                                 $tableClause .= ' ' . $this->useIndexClause(
1924                                                 implode( ',', (array)$use_index[$alias] )
1925                                         );
1926
1927                                 $ret[] = $tableClause;
1928                         } elseif ( isset( $ignore_index[$alias] ) ) {
1929                                 // Is there an INDEX clause for this table?
1930                                 $tableClause = $this->tableNameWithAlias( $table, $alias );
1931                                 $tableClause .= ' ' . $this->ignoreIndexClause(
1932                                                 implode( ',', (array)$ignore_index[$alias] )
1933                                         );
1934
1935                                 $ret[] = $tableClause;
1936                         } else {
1937                                 $tableClause = $this->tableNameWithAlias( $table, $alias );
1938
1939                                 $ret[] = $tableClause;
1940                         }
1941                 }
1942
1943                 // We can't separate explicit JOIN clauses with ',', use ' ' for those
1944                 $implicitJoins = !empty( $ret ) ? implode( ',', $ret ) : "";
1945                 $explicitJoins = !empty( $retJOIN ) ? implode( ' ', $retJOIN ) : "";
1946
1947                 // Compile our final table clause
1948                 return implode( ' ', [ $implicitJoins, $explicitJoins ] );
1949         }
1950
1951         /**
1952          * Get the name of an index in a given table.
1953          *
1954          * @param string $index
1955          * @return string
1956          */
1957         protected function indexName( $index ) {
1958                 // Backwards-compatibility hack
1959                 $renamed = [
1960                         'ar_usertext_timestamp' => 'usertext_timestamp',
1961                         'un_user_id' => 'user_id',
1962                         'un_user_ip' => 'user_ip',
1963                 ];
1964
1965                 if ( isset( $renamed[$index] ) ) {
1966                         return $renamed[$index];
1967                 } else {
1968                         return $index;
1969                 }
1970         }
1971
1972         public function addQuotes( $s ) {
1973                 if ( $s instanceof Blob ) {
1974                         $s = $s->fetch();
1975                 }
1976                 if ( $s === null ) {
1977                         return 'NULL';
1978                 } elseif ( is_bool( $s ) ) {
1979                         return (int)$s;
1980                 } else {
1981                         # This will also quote numeric values. This should be harmless,
1982                         # and protects against weird problems that occur when they really
1983                         # _are_ strings such as article titles and string->number->string
1984                         # conversion is not 1:1.
1985                         return "'" . $this->strencode( $s ) . "'";
1986                 }
1987         }
1988
1989         /**
1990          * Quotes an identifier using `backticks` or "double quotes" depending on the database type.
1991          * MySQL uses `backticks` while basically everything else uses double quotes.
1992          * Since MySQL is the odd one out here the double quotes are our generic
1993          * and we implement backticks in DatabaseMysql.
1994          *
1995          * @param string $s
1996          * @return string
1997          */
1998         public function addIdentifierQuotes( $s ) {
1999                 return '"' . str_replace( '"', '""', $s ) . '"';
2000         }
2001
2002         /**
2003          * Returns if the given identifier looks quoted or not according to
2004          * the database convention for quoting identifiers .
2005          *
2006          * @note Do not use this to determine if untrusted input is safe.
2007          *   A malicious user can trick this function.
2008          * @param string $name
2009          * @return bool
2010          */
2011         public function isQuotedIdentifier( $name ) {
2012                 return $name[0] == '"' && substr( $name, -1, 1 ) == '"';
2013         }
2014
2015         /**
2016          * @param string $s
2017          * @return string
2018          */
2019         protected function escapeLikeInternal( $s ) {
2020                 return addcslashes( $s, '\%_' );
2021         }
2022
2023         public function buildLike() {
2024                 $params = func_get_args();
2025
2026                 if ( count( $params ) > 0 && is_array( $params[0] ) ) {
2027                         $params = $params[0];
2028                 }
2029
2030                 $s = '';
2031
2032                 foreach ( $params as $value ) {
2033                         if ( $value instanceof LikeMatch ) {
2034                                 $s .= $value->toString();
2035                         } else {
2036                                 $s .= $this->escapeLikeInternal( $value );
2037                         }
2038                 }
2039
2040                 return " LIKE {$this->addQuotes( $s )} ";
2041         }
2042
2043         public function anyChar() {
2044                 return new LikeMatch( '_' );
2045         }
2046
2047         public function anyString() {
2048                 return new LikeMatch( '%' );
2049         }
2050
2051         public function nextSequenceValue( $seqName ) {
2052                 return null;
2053         }
2054
2055         /**
2056          * USE INDEX clause. Unlikely to be useful for anything but MySQL. This
2057          * is only needed because a) MySQL must be as efficient as possible due to
2058          * its use on Wikipedia, and b) MySQL 4.0 is kind of dumb sometimes about
2059          * which index to pick. Anyway, other databases might have different
2060          * indexes on a given table. So don't bother overriding this unless you're
2061          * MySQL.
2062          * @param string $index
2063          * @return string
2064          */
2065         public function useIndexClause( $index ) {
2066                 return '';
2067         }
2068
2069         /**
2070          * IGNORE INDEX clause. Unlikely to be useful for anything but MySQL. This
2071          * is only needed because a) MySQL must be as efficient as possible due to
2072          * its use on Wikipedia, and b) MySQL 4.0 is kind of dumb sometimes about
2073          * which index to pick. Anyway, other databases might have different
2074          * indexes on a given table. So don't bother overriding this unless you're
2075          * MySQL.
2076          * @param string $index
2077          * @return string
2078          */
2079         public function ignoreIndexClause( $index ) {
2080                 return '';
2081         }
2082
2083         public function replace( $table, $uniqueIndexes, $rows, $fname = __METHOD__ ) {
2084                 $quotedTable = $this->tableName( $table );
2085
2086                 if ( count( $rows ) == 0 ) {
2087                         return;
2088                 }
2089
2090                 # Single row case
2091                 if ( !is_array( reset( $rows ) ) ) {
2092                         $rows = [ $rows ];
2093                 }
2094
2095                 // @FXIME: this is not atomic, but a trx would break affectedRows()
2096                 foreach ( $rows as $row ) {
2097                         # Delete rows which collide
2098                         if ( $uniqueIndexes ) {
2099                                 $sql = "DELETE FROM $quotedTable WHERE ";
2100                                 $first = true;
2101                                 foreach ( $uniqueIndexes as $index ) {
2102                                         if ( $first ) {
2103                                                 $first = false;
2104                                                 $sql .= '( ';
2105                                         } else {
2106                                                 $sql .= ' ) OR ( ';
2107                                         }
2108                                         if ( is_array( $index ) ) {
2109                                                 $first2 = true;
2110                                                 foreach ( $index as $col ) {
2111                                                         if ( $first2 ) {
2112                                                                 $first2 = false;
2113                                                         } else {
2114                                                                 $sql .= ' AND ';
2115                                                         }
2116                                                         $sql .= $col . '=' . $this->addQuotes( $row[$col] );
2117                                                 }
2118                                         } else {
2119                                                 $sql .= $index . '=' . $this->addQuotes( $row[$index] );
2120                                         }
2121                                 }
2122                                 $sql .= ' )';
2123                                 $this->query( $sql, $fname );
2124                         }
2125
2126                         # Now insert the row
2127                         $this->insert( $table, $row, $fname );
2128                 }
2129         }
2130
2131         /**
2132          * REPLACE query wrapper for MySQL and SQLite, which have a native REPLACE
2133          * statement.
2134          *
2135          * @param string $table Table name
2136          * @param array|string $rows Row(s) to insert
2137          * @param string $fname Caller function name
2138          *
2139          * @return ResultWrapper
2140          */
2141         protected function nativeReplace( $table, $rows, $fname ) {
2142                 $table = $this->tableName( $table );
2143
2144                 # Single row case
2145                 if ( !is_array( reset( $rows ) ) ) {
2146                         $rows = [ $rows ];
2147                 }
2148
2149                 $sql = "REPLACE INTO $table (" . implode( ',', array_keys( $rows[0] ) ) . ') VALUES ';
2150                 $first = true;
2151
2152                 foreach ( $rows as $row ) {
2153                         if ( $first ) {
2154                                 $first = false;
2155                         } else {
2156                                 $sql .= ',';
2157                         }
2158
2159                         $sql .= '(' . $this->makeList( $row ) . ')';
2160                 }
2161
2162                 return $this->query( $sql, $fname );
2163         }
2164
2165         public function upsert( $table, array $rows, array $uniqueIndexes, array $set,
2166                 $fname = __METHOD__
2167         ) {
2168                 if ( !count( $rows ) ) {
2169                         return true; // nothing to do
2170                 }
2171
2172                 if ( !is_array( reset( $rows ) ) ) {
2173                         $rows = [ $rows ];
2174                 }
2175
2176                 if ( count( $uniqueIndexes ) ) {
2177                         $clauses = []; // list WHERE clauses that each identify a single row
2178                         foreach ( $rows as $row ) {
2179                                 foreach ( $uniqueIndexes as $index ) {
2180                                         $index = is_array( $index ) ? $index : [ $index ]; // columns
2181                                         $rowKey = []; // unique key to this row
2182                                         foreach ( $index as $column ) {
2183                                                 $rowKey[$column] = $row[$column];
2184                                         }
2185                                         $clauses[] = $this->makeList( $rowKey, self::LIST_AND );
2186                                 }
2187                         }
2188                         $where = [ $this->makeList( $clauses, self::LIST_OR ) ];
2189                 } else {
2190                         $where = false;
2191                 }
2192
2193                 $useTrx = !$this->mTrxLevel;
2194                 if ( $useTrx ) {
2195                         $this->begin( $fname, self::TRANSACTION_INTERNAL );
2196                 }
2197                 try {
2198                         # Update any existing conflicting row(s)
2199                         if ( $where !== false ) {
2200                                 $ok = $this->update( $table, $set, $where, $fname );
2201                         } else {
2202                                 $ok = true;
2203                         }
2204                         # Now insert any non-conflicting row(s)
2205                         $ok = $this->insert( $table, $rows, $fname, [ 'IGNORE' ] ) && $ok;
2206                 } catch ( Exception $e ) {
2207                         if ( $useTrx ) {
2208                                 $this->rollback( $fname, self::FLUSHING_INTERNAL );
2209                         }
2210                         throw $e;
2211                 }
2212                 if ( $useTrx ) {
2213                         $this->commit( $fname, self::FLUSHING_INTERNAL );
2214                 }
2215
2216                 return $ok;
2217         }
2218
2219         public function deleteJoin( $delTable, $joinTable, $delVar, $joinVar, $conds,
2220                 $fname = __METHOD__
2221         ) {
2222                 if ( !$conds ) {
2223                         throw new DBUnexpectedError( $this, __METHOD__ . ' called with empty $conds' );
2224                 }
2225
2226                 $delTable = $this->tableName( $delTable );
2227                 $joinTable = $this->tableName( $joinTable );
2228                 $sql = "DELETE FROM $delTable WHERE $delVar IN (SELECT $joinVar FROM $joinTable ";
2229                 if ( $conds != '*' ) {
2230                         $sql .= 'WHERE ' . $this->makeList( $conds, self::LIST_AND );
2231                 }
2232                 $sql .= ')';
2233
2234                 $this->query( $sql, $fname );
2235         }
2236
2237         /**
2238          * Returns the size of a text field, or -1 for "unlimited"
2239          *
2240          * @param string $table
2241          * @param string $field
2242          * @return int
2243          */
2244         public function textFieldSize( $table, $field ) {
2245                 $table = $this->tableName( $table );
2246                 $sql = "SHOW COLUMNS FROM $table LIKE \"$field\";";
2247                 $res = $this->query( $sql, __METHOD__ );
2248                 $row = $this->fetchObject( $res );
2249
2250                 $m = [];
2251
2252                 if ( preg_match( '/\((.*)\)/', $row->Type, $m ) ) {
2253                         $size = $m[1];
2254                 } else {
2255                         $size = -1;
2256                 }
2257
2258                 return $size;
2259         }
2260
2261         public function delete( $table, $conds, $fname = __METHOD__ ) {
2262                 if ( !$conds ) {
2263                         throw new DBUnexpectedError( $this, __METHOD__ . ' called with no conditions' );
2264                 }
2265
2266                 $table = $this->tableName( $table );
2267                 $sql = "DELETE FROM $table";
2268
2269                 if ( $conds != '*' ) {
2270                         if ( is_array( $conds ) ) {
2271                                 $conds = $this->makeList( $conds, self::LIST_AND );
2272                         }
2273                         $sql .= ' WHERE ' . $conds;
2274                 }
2275
2276                 return $this->query( $sql, $fname );
2277         }
2278
2279         public function insertSelect(
2280                 $destTable, $srcTable, $varMap, $conds,
2281                 $fname = __METHOD__, $insertOptions = [], $selectOptions = []
2282         ) {
2283                 if ( $this->cliMode ) {
2284                         // For massive migrations with downtime, we don't want to select everything
2285                         // into memory and OOM, so do all this native on the server side if possible.
2286                         return $this->nativeInsertSelect(
2287                                 $destTable,
2288                                 $srcTable,
2289                                 $varMap,
2290                                 $conds,
2291                                 $fname,
2292                                 $insertOptions,
2293                                 $selectOptions
2294                         );
2295                 }
2296
2297                 // For web requests, do a locking SELECT and then INSERT. This puts the SELECT burden
2298                 // on only the master (without needing row-based-replication). It also makes it easy to
2299                 // know how big the INSERT is going to be.
2300                 $fields = [];
2301                 foreach ( $varMap as $dstColumn => $sourceColumnOrSql ) {
2302                         $fields[] = $this->fieldNameWithAlias( $sourceColumnOrSql, $dstColumn );
2303                 }
2304                 $selectOptions[] = 'FOR UPDATE';
2305                 $res = $this->select( $srcTable, implode( ',', $fields ), $conds, $fname, $selectOptions );
2306                 if ( !$res ) {
2307                         return false;
2308                 }
2309
2310                 $rows = [];
2311                 foreach ( $res as $row ) {
2312                         $rows[] = (array)$row;
2313                 }
2314
2315                 return $this->insert( $destTable, $rows, $fname, $insertOptions );
2316         }
2317
2318         protected function nativeInsertSelect( $destTable, $srcTable, $varMap, $conds,
2319                 $fname = __METHOD__,
2320                 $insertOptions = [], $selectOptions = []
2321         ) {
2322                 $destTable = $this->tableName( $destTable );
2323
2324                 if ( !is_array( $insertOptions ) ) {
2325                         $insertOptions = [ $insertOptions ];
2326                 }
2327
2328                 $insertOptions = $this->makeInsertOptions( $insertOptions );
2329
2330                 if ( !is_array( $selectOptions ) ) {
2331                         $selectOptions = [ $selectOptions ];
2332                 }
2333
2334                 list( $startOpts, $useIndex, $tailOpts, $ignoreIndex ) = $this->makeSelectOptions(
2335                         $selectOptions );
2336
2337                 if ( is_array( $srcTable ) ) {
2338                         $srcTable = implode( ',', array_map( [ &$this, 'tableName' ], $srcTable ) );
2339                 } else {
2340                         $srcTable = $this->tableName( $srcTable );
2341                 }
2342
2343                 $sql = "INSERT $insertOptions INTO $destTable (" . implode( ',', array_keys( $varMap ) ) . ')' .
2344                         " SELECT $startOpts " . implode( ',', $varMap ) .
2345                         " FROM $srcTable $useIndex $ignoreIndex ";
2346
2347                 if ( $conds != '*' ) {
2348                         if ( is_array( $conds ) ) {
2349                                 $conds = $this->makeList( $conds, self::LIST_AND );
2350                         }
2351                         $sql .= " WHERE $conds";
2352                 }
2353
2354                 $sql .= " $tailOpts";
2355
2356                 return $this->query( $sql, $fname );
2357         }
2358
2359         /**
2360          * Construct a LIMIT query with optional offset. This is used for query
2361          * pages. The SQL should be adjusted so that only the first $limit rows
2362          * are returned. If $offset is provided as well, then the first $offset
2363          * rows should be discarded, and the next $limit rows should be returned.
2364          * If the result of the query is not ordered, then the rows to be returned
2365          * are theoretically arbitrary.
2366          *
2367          * $sql is expected to be a SELECT, if that makes a difference.
2368          *
2369          * The version provided by default works in MySQL and SQLite. It will very
2370          * likely need to be overridden for most other DBMSes.
2371          *
2372          * @param string $sql SQL query we will append the limit too
2373          * @param int $limit The SQL limit
2374          * @param int|bool $offset The SQL offset (default false)
2375          * @throws DBUnexpectedError
2376          * @return string
2377          */
2378         public function limitResult( $sql, $limit, $offset = false ) {
2379                 if ( !is_numeric( $limit ) ) {
2380                         throw new DBUnexpectedError( $this,
2381                                 "Invalid non-numeric limit passed to limitResult()\n" );
2382                 }
2383
2384                 return "$sql LIMIT "
2385                 . ( ( is_numeric( $offset ) && $offset != 0 ) ? "{$offset}," : "" )
2386                 . "{$limit} ";
2387         }
2388
2389         public function unionSupportsOrderAndLimit() {
2390                 return true; // True for almost every DB supported
2391         }
2392
2393         public function unionQueries( $sqls, $all ) {
2394                 $glue = $all ? ') UNION ALL (' : ') UNION (';
2395
2396                 return '(' . implode( $glue, $sqls ) . ')';
2397         }
2398
2399         public function conditional( $cond, $trueVal, $falseVal ) {
2400                 if ( is_array( $cond ) ) {
2401                         $cond = $this->makeList( $cond, self::LIST_AND );
2402                 }
2403
2404                 return " (CASE WHEN $cond THEN $trueVal ELSE $falseVal END) ";
2405         }
2406
2407         public function strreplace( $orig, $old, $new ) {
2408                 return "REPLACE({$orig}, {$old}, {$new})";
2409         }
2410
2411         public function getServerUptime() {
2412                 return 0;
2413         }
2414
2415         public function wasDeadlock() {
2416                 return false;
2417         }
2418
2419         public function wasLockTimeout() {
2420                 return false;
2421         }
2422
2423         public function wasErrorReissuable() {
2424                 return false;
2425         }
2426
2427         public function wasReadOnlyError() {
2428                 return false;
2429         }
2430
2431         /**
2432          * Do no use the class outside of Database/DBError classes
2433          *
2434          * @param integer|string $errno
2435          * @return bool Whether the given query error was a connection drop
2436          */
2437         public function wasConnectionError( $errno ) {
2438                 return false;
2439         }
2440
2441         /**
2442          * Perform a deadlock-prone transaction.
2443          *
2444          * This function invokes a callback function to perform a set of write
2445          * queries. If a deadlock occurs during the processing, the transaction
2446          * will be rolled back and the callback function will be called again.
2447          *
2448          * Avoid using this method outside of Job or Maintenance classes.
2449          *
2450          * Usage:
2451          *   $dbw->deadlockLoop( callback, ... );
2452          *
2453          * Extra arguments are passed through to the specified callback function.
2454          * This method requires that no transactions are already active to avoid
2455          * causing premature commits or exceptions.
2456          *
2457          * Returns whatever the callback function returned on its successful,
2458          * iteration, or false on error, for example if the retry limit was
2459          * reached.
2460          *
2461          * @return mixed
2462          * @throws DBUnexpectedError
2463          * @throws Exception
2464          */
2465         public function deadlockLoop() {
2466                 $args = func_get_args();
2467                 $function = array_shift( $args );
2468                 $tries = self::DEADLOCK_TRIES;
2469
2470                 $this->begin( __METHOD__ );
2471
2472                 $retVal = null;
2473                 /** @var Exception $e */
2474                 $e = null;
2475                 do {
2476                         try {
2477                                 $retVal = call_user_func_array( $function, $args );
2478                                 break;
2479                         } catch ( DBQueryError $e ) {
2480                                 if ( $this->wasDeadlock() ) {
2481                                         // Retry after a randomized delay
2482                                         usleep( mt_rand( self::DEADLOCK_DELAY_MIN, self::DEADLOCK_DELAY_MAX ) );
2483                                 } else {
2484                                         // Throw the error back up
2485                                         throw $e;
2486                                 }
2487                         }
2488                 } while ( --$tries > 0 );
2489
2490                 if ( $tries <= 0 ) {
2491                         // Too many deadlocks; give up
2492                         $this->rollback( __METHOD__ );
2493                         throw $e;
2494                 } else {
2495                         $this->commit( __METHOD__ );
2496
2497                         return $retVal;
2498                 }
2499         }
2500
2501         public function masterPosWait( DBMasterPos $pos, $timeout ) {
2502                 # Real waits are implemented in the subclass.
2503                 return 0;
2504         }
2505
2506         public function getSlavePos() {
2507                 # Stub
2508                 return false;
2509         }
2510
2511         public function getMasterPos() {
2512                 # Stub
2513                 return false;
2514         }
2515
2516         public function serverIsReadOnly() {
2517                 return false;
2518         }
2519
2520         final public function onTransactionResolution( callable $callback, $fname = __METHOD__ ) {
2521                 if ( !$this->mTrxLevel ) {
2522                         throw new DBUnexpectedError( $this, "No transaction is active." );
2523                 }
2524                 $this->mTrxEndCallbacks[] = [ $callback, $fname ];
2525         }
2526
2527         final public function onTransactionIdle( callable $callback, $fname = __METHOD__ ) {
2528                 $this->mTrxIdleCallbacks[] = [ $callback, $fname ];
2529                 if ( !$this->mTrxLevel ) {
2530                         $this->runOnTransactionIdleCallbacks( self::TRIGGER_IDLE );
2531                 }
2532         }
2533
2534         final public function onTransactionPreCommitOrIdle( callable $callback, $fname = __METHOD__ ) {
2535                 if ( $this->mTrxLevel ) {
2536                         $this->mTrxPreCommitCallbacks[] = [ $callback, $fname ];
2537                 } else {
2538                         // If no transaction is active, then make one for this callback
2539                         $this->startAtomic( __METHOD__ );
2540                         try {
2541                                 call_user_func( $callback );
2542                                 $this->endAtomic( __METHOD__ );
2543                         } catch ( Exception $e ) {
2544                                 $this->rollback( __METHOD__, self::FLUSHING_INTERNAL );
2545                                 throw $e;
2546                         }
2547                 }
2548         }
2549
2550         final public function setTransactionListener( $name, callable $callback = null ) {
2551                 if ( $callback ) {
2552                         $this->mTrxRecurringCallbacks[$name] = $callback;
2553                 } else {
2554                         unset( $this->mTrxRecurringCallbacks[$name] );
2555                 }
2556         }
2557
2558         /**
2559          * Whether to disable running of post-COMMIT/ROLLBACK callbacks
2560          *
2561          * This method should not be used outside of Database/LoadBalancer
2562          *
2563          * @param bool $suppress
2564          * @since 1.28
2565          */
2566         final public function setTrxEndCallbackSuppression( $suppress ) {
2567                 $this->mTrxEndCallbacksSuppressed = $suppress;
2568         }
2569
2570         /**
2571          * Actually run and consume any "on transaction idle/resolution" callbacks.
2572          *
2573          * This method should not be used outside of Database/LoadBalancer
2574          *
2575          * @param integer $trigger IDatabase::TRIGGER_* constant
2576          * @since 1.20
2577          * @throws Exception
2578          */
2579         public function runOnTransactionIdleCallbacks( $trigger ) {
2580                 if ( $this->mTrxEndCallbacksSuppressed ) {
2581                         return;
2582                 }
2583
2584                 $autoTrx = $this->getFlag( DBO_TRX ); // automatic begin() enabled?
2585                 /** @var Exception $e */
2586                 $e = null; // first exception
2587                 do { // callbacks may add callbacks :)
2588                         $callbacks = array_merge(
2589                                 $this->mTrxIdleCallbacks,
2590                                 $this->mTrxEndCallbacks // include "transaction resolution" callbacks
2591                         );
2592                         $this->mTrxIdleCallbacks = []; // consumed (and recursion guard)
2593                         $this->mTrxEndCallbacks = []; // consumed (recursion guard)
2594                         foreach ( $callbacks as $callback ) {
2595                                 try {
2596                                         list( $phpCallback ) = $callback;
2597                                         $this->clearFlag( DBO_TRX ); // make each query its own transaction
2598                                         call_user_func_array( $phpCallback, [ $trigger ] );
2599                                         if ( $autoTrx ) {
2600                                                 $this->setFlag( DBO_TRX ); // restore automatic begin()
2601                                         } else {
2602                                                 $this->clearFlag( DBO_TRX ); // restore auto-commit
2603                                         }
2604                                 } catch ( Exception $ex ) {
2605                                         call_user_func( $this->errorLogger, $ex );
2606                                         $e = $e ?: $ex;
2607                                         // Some callbacks may use startAtomic/endAtomic, so make sure
2608                                         // their transactions are ended so other callbacks don't fail
2609                                         if ( $this->trxLevel() ) {
2610                                                 $this->rollback( __METHOD__, self::FLUSHING_INTERNAL );
2611                                         }
2612                                 }
2613                         }
2614                 } while ( count( $this->mTrxIdleCallbacks ) );
2615
2616                 if ( $e instanceof Exception ) {
2617                         throw $e; // re-throw any first exception
2618                 }
2619         }
2620
2621         /**
2622          * Actually run and consume any "on transaction pre-commit" callbacks.
2623          *
2624          * This method should not be used outside of Database/LoadBalancer
2625          *
2626          * @since 1.22
2627          * @throws Exception
2628          */
2629         public function runOnTransactionPreCommitCallbacks() {
2630                 $e = null; // first exception
2631                 do { // callbacks may add callbacks :)
2632                         $callbacks = $this->mTrxPreCommitCallbacks;
2633                         $this->mTrxPreCommitCallbacks = []; // consumed (and recursion guard)
2634                         foreach ( $callbacks as $callback ) {
2635                                 try {
2636                                         list( $phpCallback ) = $callback;
2637                                         call_user_func( $phpCallback );
2638                                 } catch ( Exception $ex ) {
2639                                         call_user_func( $this->errorLogger, $ex );
2640                                         $e = $e ?: $ex;
2641                                 }
2642                         }
2643                 } while ( count( $this->mTrxPreCommitCallbacks ) );
2644
2645                 if ( $e instanceof Exception ) {
2646                         throw $e; // re-throw any first exception
2647                 }
2648         }
2649
2650         /**
2651          * Actually run any "transaction listener" callbacks.
2652          *
2653          * This method should not be used outside of Database/LoadBalancer
2654          *
2655          * @param integer $trigger IDatabase::TRIGGER_* constant
2656          * @throws Exception
2657          * @since 1.20
2658          */
2659         public function runTransactionListenerCallbacks( $trigger ) {
2660                 if ( $this->mTrxEndCallbacksSuppressed ) {
2661                         return;
2662                 }
2663
2664                 /** @var Exception $e */
2665                 $e = null; // first exception
2666
2667                 foreach ( $this->mTrxRecurringCallbacks as $phpCallback ) {
2668                         try {
2669                                 $phpCallback( $trigger, $this );
2670                         } catch ( Exception $ex ) {
2671                                 call_user_func( $this->errorLogger, $ex );
2672                                 $e = $e ?: $ex;
2673                         }
2674                 }
2675
2676                 if ( $e instanceof Exception ) {
2677                         throw $e; // re-throw any first exception
2678                 }
2679         }
2680
2681         final public function startAtomic( $fname = __METHOD__ ) {
2682                 if ( !$this->mTrxLevel ) {
2683                         $this->begin( $fname, self::TRANSACTION_INTERNAL );
2684                         // If DBO_TRX is set, a series of startAtomic/endAtomic pairs will result
2685                         // in all changes being in one transaction to keep requests transactional.
2686                         if ( !$this->getFlag( DBO_TRX ) ) {
2687                                 $this->mTrxAutomaticAtomic = true;
2688                         }
2689                 }
2690
2691                 $this->mTrxAtomicLevels[] = $fname;
2692         }
2693
2694         final public function endAtomic( $fname = __METHOD__ ) {
2695                 if ( !$this->mTrxLevel ) {
2696                         throw new DBUnexpectedError( $this, "No atomic transaction is open (got $fname)." );
2697                 }
2698                 if ( !$this->mTrxAtomicLevels ||
2699                         array_pop( $this->mTrxAtomicLevels ) !== $fname
2700                 ) {
2701                         throw new DBUnexpectedError( $this, "Invalid atomic section ended (got $fname)." );
2702                 }
2703
2704                 if ( !$this->mTrxAtomicLevels && $this->mTrxAutomaticAtomic ) {
2705                         $this->commit( $fname, self::FLUSHING_INTERNAL );
2706                 }
2707         }
2708
2709         final public function doAtomicSection( $fname, callable $callback ) {
2710                 $this->startAtomic( $fname );
2711                 try {
2712                         $res = call_user_func_array( $callback, [ $this, $fname ] );
2713                 } catch ( Exception $e ) {
2714                         $this->rollback( $fname, self::FLUSHING_INTERNAL );
2715                         throw $e;
2716                 }
2717                 $this->endAtomic( $fname );
2718
2719                 return $res;
2720         }
2721
2722         final public function begin( $fname = __METHOD__, $mode = self::TRANSACTION_EXPLICIT ) {
2723                 // Protect against mismatched atomic section, transaction nesting, and snapshot loss
2724                 if ( $this->mTrxLevel ) {
2725                         if ( $this->mTrxAtomicLevels ) {
2726                                 $levels = implode( ', ', $this->mTrxAtomicLevels );
2727                                 $msg = "$fname: Got explicit BEGIN while atomic section(s) $levels are open.";
2728                                 throw new DBUnexpectedError( $this, $msg );
2729                         } elseif ( !$this->mTrxAutomatic ) {
2730                                 $msg = "$fname: Explicit transaction already active (from {$this->mTrxFname}).";
2731                                 throw new DBUnexpectedError( $this, $msg );
2732                         } else {
2733                                 // @TODO: make this an exception at some point
2734                                 $msg = "$fname: Implicit transaction already active (from {$this->mTrxFname}).";
2735                                 $this->queryLogger->error( $msg );
2736                                 return; // join the main transaction set
2737                         }
2738                 } elseif ( $this->getFlag( DBO_TRX ) && $mode !== self::TRANSACTION_INTERNAL ) {
2739                         // @TODO: make this an exception at some point
2740                         $msg = "$fname: Implicit transaction expected (DBO_TRX set).";
2741                         $this->queryLogger->error( $msg );
2742                         return; // let any writes be in the main transaction
2743                 }
2744
2745                 // Avoid fatals if close() was called
2746                 $this->assertOpen();
2747
2748                 $this->doBegin( $fname );
2749                 $this->mTrxTimestamp = microtime( true );
2750                 $this->mTrxFname = $fname;
2751                 $this->mTrxDoneWrites = false;
2752                 $this->mTrxAutomatic = ( $mode === self::TRANSACTION_INTERNAL );
2753                 $this->mTrxAutomaticAtomic = false;
2754                 $this->mTrxAtomicLevels = [];
2755                 $this->mTrxShortId = sprintf( '%06x', mt_rand( 0, 0xffffff ) );
2756                 $this->mTrxWriteDuration = 0.0;
2757                 $this->mTrxWriteQueryCount = 0;
2758                 $this->mTrxWriteAdjDuration = 0.0;
2759                 $this->mTrxWriteAdjQueryCount = 0;
2760                 $this->mTrxWriteCallers = [];
2761                 // First SELECT after BEGIN will establish the snapshot in REPEATABLE-READ.
2762                 // Get an estimate of the replica DB lag before then, treating estimate staleness
2763                 // as lag itself just to be safe
2764                 $status = $this->getApproximateLagStatus();
2765                 $this->mTrxReplicaLag = $status['lag'] + ( microtime( true ) - $status['since'] );
2766         }
2767
2768         /**
2769          * Issues the BEGIN command to the database server.
2770          *
2771          * @see DatabaseBase::begin()
2772          * @param string $fname
2773          */
2774         protected function doBegin( $fname ) {
2775                 $this->query( 'BEGIN', $fname );
2776                 $this->mTrxLevel = 1;
2777         }
2778
2779         final public function commit( $fname = __METHOD__, $flush = '' ) {
2780                 if ( $this->mTrxLevel && $this->mTrxAtomicLevels ) {
2781                         // There are still atomic sections open. This cannot be ignored
2782                         $levels = implode( ', ', $this->mTrxAtomicLevels );
2783                         throw new DBUnexpectedError(
2784                                 $this,
2785                                 "$fname: Got COMMIT while atomic sections $levels are still open."
2786                         );
2787                 }
2788
2789                 if ( $flush === self::FLUSHING_INTERNAL || $flush === self::FLUSHING_ALL_PEERS ) {
2790                         if ( !$this->mTrxLevel ) {
2791                                 return; // nothing to do
2792                         } elseif ( !$this->mTrxAutomatic ) {
2793                                 throw new DBUnexpectedError(
2794                                         $this,
2795                                         "$fname: Flushing an explicit transaction, getting out of sync."
2796                                 );
2797                         }
2798                 } else {
2799                         if ( !$this->mTrxLevel ) {
2800                                 $this->queryLogger->error( "$fname: No transaction to commit, something got out of sync." );
2801                                 return; // nothing to do
2802                         } elseif ( $this->mTrxAutomatic ) {
2803                                 // @TODO: make this an exception at some point
2804                                 $msg = "$fname: Explicit commit of implicit transaction.";
2805                                 $this->queryLogger->error( $msg );
2806                                 return; // wait for the main transaction set commit round
2807                         }
2808                 }
2809
2810                 // Avoid fatals if close() was called
2811                 $this->assertOpen();
2812
2813                 $this->runOnTransactionPreCommitCallbacks();
2814                 $writeTime = $this->pendingWriteQueryDuration( self::ESTIMATE_DB_APPLY );
2815                 $this->doCommit( $fname );
2816                 if ( $this->mTrxDoneWrites ) {
2817                         $this->mDoneWrites = microtime( true );
2818                         $this->trxProfiler->transactionWritingOut(
2819                                 $this->mServer, $this->mDBname, $this->mTrxShortId, $writeTime );
2820                 }
2821
2822                 $this->runOnTransactionIdleCallbacks( self::TRIGGER_COMMIT );
2823                 $this->runTransactionListenerCallbacks( self::TRIGGER_COMMIT );
2824         }
2825
2826         /**
2827          * Issues the COMMIT command to the database server.
2828          *
2829          * @see DatabaseBase::commit()
2830          * @param string $fname
2831          */
2832         protected function doCommit( $fname ) {
2833                 if ( $this->mTrxLevel ) {
2834                         $this->query( 'COMMIT', $fname );
2835                         $this->mTrxLevel = 0;
2836                 }
2837         }
2838
2839         final public function rollback( $fname = __METHOD__, $flush = '' ) {
2840                 if ( $flush === self::FLUSHING_INTERNAL || $flush === self::FLUSHING_ALL_PEERS ) {
2841                         if ( !$this->mTrxLevel ) {
2842                                 return; // nothing to do
2843                         }
2844                 } else {
2845                         if ( !$this->mTrxLevel ) {
2846                                 $this->queryLogger->error(
2847                                         "$fname: No transaction to rollback, something got out of sync." );
2848                                 return; // nothing to do
2849                         } elseif ( $this->getFlag( DBO_TRX ) ) {
2850                                 throw new DBUnexpectedError(
2851                                         $this,
2852                                         "$fname: Expected mass rollback of all peer databases (DBO_TRX set)."
2853                                 );
2854                         }
2855                 }
2856
2857                 // Avoid fatals if close() was called
2858                 $this->assertOpen();
2859
2860                 $this->doRollback( $fname );
2861                 $this->mTrxAtomicLevels = [];
2862                 if ( $this->mTrxDoneWrites ) {
2863                         $this->trxProfiler->transactionWritingOut(
2864                                 $this->mServer, $this->mDBname, $this->mTrxShortId );
2865                 }
2866
2867                 $this->mTrxIdleCallbacks = []; // clear
2868                 $this->mTrxPreCommitCallbacks = []; // clear
2869                 $this->runOnTransactionIdleCallbacks( self::TRIGGER_ROLLBACK );
2870                 $this->runTransactionListenerCallbacks( self::TRIGGER_ROLLBACK );
2871         }
2872
2873         /**
2874          * Issues the ROLLBACK command to the database server.
2875          *
2876          * @see DatabaseBase::rollback()
2877          * @param string $fname
2878          */
2879         protected function doRollback( $fname ) {
2880                 if ( $this->mTrxLevel ) {
2881                         # Disconnects cause rollback anyway, so ignore those errors
2882                         $ignoreErrors = true;
2883                         $this->query( 'ROLLBACK', $fname, $ignoreErrors );
2884                         $this->mTrxLevel = 0;
2885                 }
2886         }
2887
2888         public function flushSnapshot( $fname = __METHOD__ ) {
2889                 if ( $this->writesOrCallbacksPending() || $this->explicitTrxActive() ) {
2890                         // This only flushes transactions to clear snapshots, not to write data
2891                         $fnames = implode( ', ', $this->pendingWriteAndCallbackCallers() );
2892                         throw new DBUnexpectedError(
2893                                 $this,
2894                                 "$fname: Cannot COMMIT to clear snapshot because writes are pending ($fnames)."
2895                         );
2896                 }
2897
2898                 $this->commit( $fname, self::FLUSHING_INTERNAL );
2899         }
2900
2901         public function explicitTrxActive() {
2902                 return $this->mTrxLevel && ( $this->mTrxAtomicLevels || !$this->mTrxAutomatic );
2903         }
2904
2905         /**
2906          * Creates a new table with structure copied from existing table
2907          * Note that unlike most database abstraction functions, this function does not
2908          * automatically append database prefix, because it works at a lower
2909          * abstraction level.
2910          * The table names passed to this function shall not be quoted (this
2911          * function calls addIdentifierQuotes when needed).
2912          *
2913          * @param string $oldName Name of table whose structure should be copied
2914          * @param string $newName Name of table to be created
2915          * @param bool $temporary Whether the new table should be temporary
2916          * @param string $fname Calling function name
2917          * @throws RuntimeException
2918          * @return bool True if operation was successful
2919          */
2920         public function duplicateTableStructure( $oldName, $newName, $temporary = false,
2921                 $fname = __METHOD__
2922         ) {
2923                 throw new RuntimeException( __METHOD__ . ' is not implemented in descendant class' );
2924         }
2925
2926         public function listTables( $prefix = null, $fname = __METHOD__ ) {
2927                 throw new RuntimeException( __METHOD__ . ' is not implemented in descendant class' );
2928         }
2929
2930         /**
2931          * Reset the views process cache set by listViews()
2932          * @since 1.22
2933          */
2934         final public function clearViewsCache() {
2935                 $this->allViews = null;
2936         }
2937
2938         /**
2939          * Lists all the VIEWs in the database
2940          *
2941          * For caching purposes the list of all views should be stored in
2942          * $this->allViews. The process cache can be cleared with clearViewsCache()
2943          *
2944          * @param string $prefix Only show VIEWs with this prefix, eg. unit_test_
2945          * @param string $fname Name of calling function
2946          * @throws RuntimeException
2947          * @return array
2948          * @since 1.22
2949          */
2950         public function listViews( $prefix = null, $fname = __METHOD__ ) {
2951                 throw new RuntimeException( __METHOD__ . ' is not implemented in descendant class' );
2952         }
2953
2954         /**
2955          * Differentiates between a TABLE and a VIEW
2956          *
2957          * @param string $name Name of the database-structure to test.
2958          * @throws RuntimeException
2959          * @return bool
2960          * @since 1.22
2961          */
2962         public function isView( $name ) {
2963                 throw new RuntimeException( __METHOD__ . ' is not implemented in descendant class' );
2964         }
2965
2966         public function timestamp( $ts = 0 ) {
2967                 $t = new ConvertableTimestamp( $ts );
2968                 // Let errors bubble up to avoid putting garbage in the DB
2969                 return $t->getTimestamp( TS_MW );
2970         }
2971
2972         public function timestampOrNull( $ts = null ) {
2973                 if ( is_null( $ts ) ) {
2974                         return null;
2975                 } else {
2976                         return $this->timestamp( $ts );
2977                 }
2978         }
2979
2980         /**
2981          * Take the result from a query, and wrap it in a ResultWrapper if
2982          * necessary. Boolean values are passed through as is, to indicate success
2983          * of write queries or failure.
2984          *
2985          * Once upon a time, DatabaseBase::query() returned a bare MySQL result
2986          * resource, and it was necessary to call this function to convert it to
2987          * a wrapper. Nowadays, raw database objects are never exposed to external
2988          * callers, so this is unnecessary in external code.
2989          *
2990          * @param bool|ResultWrapper|resource|object $result
2991          * @return bool|ResultWrapper
2992          */
2993         protected function resultObject( $result ) {
2994                 if ( !$result ) {
2995                         return false;
2996                 } elseif ( $result instanceof ResultWrapper ) {
2997                         return $result;
2998                 } elseif ( $result === true ) {
2999                         // Successful write query
3000                         return $result;
3001                 } else {
3002                         return new ResultWrapper( $this, $result );
3003                 }
3004         }
3005
3006         public function ping( &$rtt = null ) {
3007                 // Avoid hitting the server if it was hit recently
3008                 if ( $this->isOpen() && ( microtime( true ) - $this->lastPing ) < self::PING_TTL ) {
3009                         if ( !func_num_args() || $this->mRTTEstimate > 0 ) {
3010                                 $rtt = $this->mRTTEstimate;
3011                                 return true; // don't care about $rtt
3012                         }
3013                 }
3014
3015                 // This will reconnect if possible or return false if not
3016                 $this->clearFlag( DBO_TRX, self::REMEMBER_PRIOR );
3017                 $ok = ( $this->query( self::PING_QUERY, __METHOD__, true ) !== false );
3018                 $this->restoreFlags( self::RESTORE_PRIOR );
3019
3020                 if ( $ok ) {
3021                         $rtt = $this->mRTTEstimate;
3022                 }
3023
3024                 return $ok;
3025         }
3026
3027         /**
3028          * @return bool
3029          */
3030         protected function reconnect() {
3031                 $this->closeConnection();
3032                 $this->mOpened = false;
3033                 $this->mConn = false;
3034                 try {
3035                         $this->open( $this->mServer, $this->mUser, $this->mPassword, $this->mDBname );
3036                         $this->lastPing = microtime( true );
3037                         $ok = true;
3038                 } catch ( DBConnectionError $e ) {
3039                         $ok = false;
3040                 }
3041
3042                 return $ok;
3043         }
3044
3045         public function getSessionLagStatus() {
3046                 return $this->getTransactionLagStatus() ?: $this->getApproximateLagStatus();
3047         }
3048
3049         /**
3050          * Get the replica DB lag when the current transaction started
3051          *
3052          * This is useful when transactions might use snapshot isolation
3053          * (e.g. REPEATABLE-READ in innodb), so the "real" lag of that data
3054          * is this lag plus transaction duration. If they don't, it is still
3055          * safe to be pessimistic. This returns null if there is no transaction.
3056          *
3057          * @return array|null ('lag': seconds or false on error, 'since': UNIX timestamp of BEGIN)
3058          * @since 1.27
3059          */
3060         protected function getTransactionLagStatus() {
3061                 return $this->mTrxLevel
3062                         ? [ 'lag' => $this->mTrxReplicaLag, 'since' => $this->trxTimestamp() ]
3063                         : null;
3064         }
3065
3066         /**
3067          * Get a replica DB lag estimate for this server
3068          *
3069          * @return array ('lag': seconds or false on error, 'since': UNIX timestamp of estimate)
3070          * @since 1.27
3071          */
3072         protected function getApproximateLagStatus() {
3073                 return [
3074                         'lag'   => $this->getLBInfo( 'replica' ) ? $this->getLag() : 0,
3075                         'since' => microtime( true )
3076                 ];
3077         }
3078
3079         /**
3080          * Merge the result of getSessionLagStatus() for several DBs
3081          * using the most pessimistic values to estimate the lag of
3082          * any data derived from them in combination
3083          *
3084          * This is information is useful for caching modules
3085          *
3086          * @see WANObjectCache::set()
3087          * @see WANObjectCache::getWithSetCallback()
3088          *
3089          * @param IDatabase $db1
3090          * @param IDatabase ...
3091          * @return array Map of values:
3092          *   - lag: highest lag of any of the DBs or false on error (e.g. replication stopped)
3093          *   - since: oldest UNIX timestamp of any of the DB lag estimates
3094          *   - pending: whether any of the DBs have uncommitted changes
3095          * @since 1.27
3096          */
3097         public static function getCacheSetOptions( IDatabase $db1 ) {
3098                 $res = [ 'lag' => 0, 'since' => INF, 'pending' => false ];
3099                 foreach ( func_get_args() as $db ) {
3100                         /** @var IDatabase $db */
3101                         $status = $db->getSessionLagStatus();
3102                         if ( $status['lag'] === false ) {
3103                                 $res['lag'] = false;
3104                         } elseif ( $res['lag'] !== false ) {
3105                                 $res['lag'] = max( $res['lag'], $status['lag'] );
3106                         }
3107                         $res['since'] = min( $res['since'], $status['since'] );
3108                         $res['pending'] = $res['pending'] ?: $db->writesPending();
3109                 }
3110
3111                 return $res;
3112         }
3113
3114         public function getLag() {
3115                 return 0;
3116         }
3117
3118         public function maxListLen() {
3119                 return 0;
3120         }
3121
3122         public function encodeBlob( $b ) {
3123                 return $b;
3124         }
3125
3126         public function decodeBlob( $b ) {
3127                 if ( $b instanceof Blob ) {
3128                         $b = $b->fetch();
3129                 }
3130                 return $b;
3131         }
3132
3133         public function setSessionOptions( array $options ) {
3134         }
3135
3136         /**
3137          * Read and execute SQL commands from a file.
3138          *
3139          * Returns true on success, error string or exception on failure (depending
3140          * on object's error ignore settings).
3141          *
3142          * @param string $filename File name to open
3143          * @param bool|callable $lineCallback Optional function called before reading each line
3144          * @param bool|callable $resultCallback Optional function called for each MySQL result
3145          * @param bool|string $fname Calling function name or false if name should be
3146          *   generated dynamically using $filename
3147          * @param bool|callable $inputCallback Optional function called for each
3148          *   complete line sent
3149          * @return bool|string
3150          * @throws Exception
3151          */
3152         public function sourceFile(
3153                 $filename, $lineCallback = false, $resultCallback = false, $fname = false, $inputCallback = false
3154         ) {
3155                 MediaWiki\suppressWarnings();
3156                 $fp = fopen( $filename, 'r' );
3157                 MediaWiki\restoreWarnings();
3158
3159                 if ( false === $fp ) {
3160                         throw new RuntimeException( "Could not open \"{$filename}\".\n" );
3161                 }
3162
3163                 if ( !$fname ) {
3164                         $fname = __METHOD__ . "( $filename )";
3165                 }
3166
3167                 try {
3168                         $error = $this->sourceStream( $fp, $lineCallback, $resultCallback, $fname, $inputCallback );
3169                 } catch ( Exception $e ) {
3170                         fclose( $fp );
3171                         throw $e;
3172                 }
3173
3174                 fclose( $fp );
3175
3176                 return $error;
3177         }
3178
3179         public function setSchemaVars( $vars ) {
3180                 $this->mSchemaVars = $vars;
3181         }
3182
3183         /**
3184          * Read and execute commands from an open file handle.
3185          *
3186          * Returns true on success, error string or exception on failure (depending
3187          * on object's error ignore settings).
3188          *
3189          * @param resource $fp File handle
3190          * @param bool|callable $lineCallback Optional function called before reading each query
3191          * @param bool|callable $resultCallback Optional function called for each MySQL result
3192          * @param string $fname Calling function name
3193          * @param bool|callable $inputCallback Optional function called for each complete query sent
3194          * @return bool|string
3195          */
3196         public function sourceStream( $fp, $lineCallback = false, $resultCallback = false,
3197                 $fname = __METHOD__, $inputCallback = false
3198         ) {
3199                 $cmd = '';
3200
3201                 while ( !feof( $fp ) ) {
3202                         if ( $lineCallback ) {
3203                                 call_user_func( $lineCallback );
3204                         }
3205
3206                         $line = trim( fgets( $fp ) );
3207
3208                         if ( $line == '' ) {
3209                                 continue;
3210                         }
3211
3212                         if ( '-' == $line[0] && '-' == $line[1] ) {
3213                                 continue;
3214                         }
3215
3216                         if ( $cmd != '' ) {
3217                                 $cmd .= ' ';
3218                         }
3219
3220                         $done = $this->streamStatementEnd( $cmd, $line );
3221
3222                         $cmd .= "$line\n";
3223
3224                         if ( $done || feof( $fp ) ) {
3225                                 $cmd = $this->replaceVars( $cmd );
3226
3227                                 if ( ( $inputCallback && call_user_func( $inputCallback, $cmd ) ) || !$inputCallback ) {
3228                                         $res = $this->query( $cmd, $fname );
3229
3230                                         if ( $resultCallback ) {
3231                                                 call_user_func( $resultCallback, $res, $this );
3232                                         }
3233
3234                                         if ( false === $res ) {
3235                                                 $err = $this->lastError();
3236
3237                                                 return "Query \"{$cmd}\" failed with error code \"$err\".\n";
3238                                         }
3239                                 }
3240                                 $cmd = '';
3241                         }
3242                 }
3243
3244                 return true;
3245         }
3246
3247         /**
3248          * Called by sourceStream() to check if we've reached a statement end
3249          *
3250          * @param string $sql SQL assembled so far
3251          * @param string $newLine New line about to be added to $sql
3252          * @return bool Whether $newLine contains end of the statement
3253          */
3254         public function streamStatementEnd( &$sql, &$newLine ) {
3255                 if ( $this->delimiter ) {
3256                         $prev = $newLine;
3257                         $newLine = preg_replace( '/' . preg_quote( $this->delimiter, '/' ) . '$/', '', $newLine );
3258                         if ( $newLine != $prev ) {
3259                                 return true;
3260                         }
3261                 }
3262
3263                 return false;
3264         }
3265
3266         /**
3267          * Database independent variable replacement. Replaces a set of variables
3268          * in an SQL statement with their contents as given by $this->getSchemaVars().
3269          *
3270          * Supports '{$var}' `{$var}` and / *$var* / (without the spaces) style variables.
3271          *
3272          * - '{$var}' should be used for text and is passed through the database's
3273          *   addQuotes method.
3274          * - `{$var}` should be used for identifiers (e.g. table and database names).
3275          *   It is passed through the database's addIdentifierQuotes method which
3276          *   can be overridden if the database uses something other than backticks.
3277          * - / *_* / or / *$wgDBprefix* / passes the name that follows through the
3278          *   database's tableName method.
3279          * - / *i* / passes the name that follows through the database's indexName method.
3280          * - In all other cases, / *$var* / is left unencoded. Except for table options,
3281          *   its use should be avoided. In 1.24 and older, string encoding was applied.
3282          *
3283          * @param string $ins SQL statement to replace variables in
3284          * @return string The new SQL statement with variables replaced
3285          */
3286         protected function replaceVars( $ins ) {
3287                 $vars = $this->getSchemaVars();
3288                 return preg_replace_callback(
3289                         '!
3290                                 /\* (\$wgDBprefix|[_i]) \*/ (\w*) | # 1-2. tableName, indexName
3291                                 \'\{\$ (\w+) }\'                  | # 3. addQuotes
3292                                 `\{\$ (\w+) }`                    | # 4. addIdentifierQuotes
3293                                 /\*\$ (\w+) \*/                     # 5. leave unencoded
3294                         !x',
3295                         function ( $m ) use ( $vars ) {
3296                                 // Note: Because of <https://bugs.php.net/bug.php?id=51881>,
3297                                 // check for both nonexistent keys *and* the empty string.
3298                                 if ( isset( $m[1] ) && $m[1] !== '' ) {
3299                                         if ( $m[1] === 'i' ) {
3300                                                 return $this->indexName( $m[2] );
3301                                         } else {
3302                                                 return $this->tableName( $m[2] );
3303                                         }
3304                                 } elseif ( isset( $m[3] ) && $m[3] !== '' && array_key_exists( $m[3], $vars ) ) {
3305                                         return $this->addQuotes( $vars[$m[3]] );
3306                                 } elseif ( isset( $m[4] ) && $m[4] !== '' && array_key_exists( $m[4], $vars ) ) {
3307                                         return $this->addIdentifierQuotes( $vars[$m[4]] );
3308                                 } elseif ( isset( $m[5] ) && $m[5] !== '' && array_key_exists( $m[5], $vars ) ) {
3309                                         return $vars[$m[5]];
3310                                 } else {
3311                                         return $m[0];
3312                                 }
3313                         },
3314                         $ins
3315                 );
3316         }
3317
3318         /**
3319          * Get schema variables. If none have been set via setSchemaVars(), then
3320          * use some defaults from the current object.
3321          *
3322          * @return array
3323          */
3324         protected function getSchemaVars() {
3325                 if ( $this->mSchemaVars ) {
3326                         return $this->mSchemaVars;
3327                 } else {
3328                         return $this->getDefaultSchemaVars();
3329                 }
3330         }
3331
3332         /**
3333          * Get schema variables to use if none have been set via setSchemaVars().
3334          *
3335          * Override this in derived classes to provide variables for tables.sql
3336          * and SQL patch files.
3337          *
3338          * @return array
3339          */
3340         protected function getDefaultSchemaVars() {
3341                 return [];
3342         }
3343
3344         public function lockIsFree( $lockName, $method ) {
3345                 return true;
3346         }
3347
3348         public function lock( $lockName, $method, $timeout = 5 ) {
3349                 $this->mNamedLocksHeld[$lockName] = 1;
3350
3351                 return true;
3352         }
3353
3354         public function unlock( $lockName, $method ) {
3355                 unset( $this->mNamedLocksHeld[$lockName] );
3356
3357                 return true;
3358         }
3359
3360         public function getScopedLockAndFlush( $lockKey, $fname, $timeout ) {
3361                 if ( $this->writesOrCallbacksPending() ) {
3362                         // This only flushes transactions to clear snapshots, not to write data
3363                         $fnames = implode( ', ', $this->pendingWriteAndCallbackCallers() );
3364                         throw new DBUnexpectedError(
3365                                 $this,
3366                                 "$fname: Cannot COMMIT to clear snapshot because writes are pending ($fnames)."
3367                         );
3368                 }
3369
3370                 if ( !$this->lock( $lockKey, $fname, $timeout ) ) {
3371                         return null;
3372                 }
3373
3374                 $unlocker = new ScopedCallback( function () use ( $lockKey, $fname ) {
3375                         if ( $this->trxLevel() ) {
3376                                 // There is a good chance an exception was thrown, causing any early return
3377                                 // from the caller. Let any error handler get a chance to issue rollback().
3378                                 // If there isn't one, let the error bubble up and trigger server-side rollback.
3379                                 $this->onTransactionResolution(
3380                                         function () use ( $lockKey, $fname ) {
3381                                                 $this->unlock( $lockKey, $fname );
3382                                         },
3383                                         $fname
3384                                 );
3385                         } else {
3386                                 $this->unlock( $lockKey, $fname );
3387                         }
3388                 } );
3389
3390                 $this->commit( $fname, self::FLUSHING_INTERNAL );
3391
3392                 return $unlocker;
3393         }
3394
3395         public function namedLocksEnqueue() {
3396                 return false;
3397         }
3398
3399         /**
3400          * Lock specific tables
3401          *
3402          * @param array $read Array of tables to lock for read access
3403          * @param array $write Array of tables to lock for write access
3404          * @param string $method Name of caller
3405          * @param bool $lowPriority Whether to indicate writes to be LOW PRIORITY
3406          * @return bool
3407          */
3408         public function lockTables( $read, $write, $method, $lowPriority = true ) {
3409                 return true;
3410         }
3411
3412         /**
3413          * Unlock specific tables
3414          *
3415          * @param string $method The caller
3416          * @return bool
3417          */
3418         public function unlockTables( $method ) {
3419                 return true;
3420         }
3421
3422         /**
3423          * Delete a table
3424          * @param string $tableName
3425          * @param string $fName
3426          * @return bool|ResultWrapper
3427          * @since 1.18
3428          */
3429         public function dropTable( $tableName, $fName = __METHOD__ ) {
3430                 if ( !$this->tableExists( $tableName, $fName ) ) {
3431                         return false;
3432                 }
3433                 $sql = "DROP TABLE " . $this->tableName( $tableName ) . " CASCADE";
3434
3435                 return $this->query( $sql, $fName );
3436         }
3437
3438         public function getInfinity() {
3439                 return 'infinity';
3440         }
3441
3442         public function encodeExpiry( $expiry ) {
3443                 return ( $expiry == '' || $expiry == 'infinity' || $expiry == $this->getInfinity() )
3444                         ? $this->getInfinity()
3445                         : $this->timestamp( $expiry );
3446         }
3447
3448         public function decodeExpiry( $expiry, $format = TS_MW ) {
3449                 if ( $expiry == '' || $expiry == 'infinity' || $expiry == $this->getInfinity() ) {
3450                         return 'infinity';
3451                 }
3452
3453                 try {
3454                         $t = new ConvertableTimestamp( $expiry );
3455
3456                         return $t->getTimestamp( $format );
3457                 } catch ( TimestampException $e ) {
3458                         return false;
3459                 }
3460         }
3461
3462         public function setBigSelects( $value = true ) {
3463                 // no-op
3464         }
3465
3466         public function isReadOnly() {
3467                 return ( $this->getReadOnlyReason() !== false );
3468         }
3469
3470         /**
3471          * @return string|bool Reason this DB is read-only or false if it is not
3472          */
3473         protected function getReadOnlyReason() {
3474                 $reason = $this->getLBInfo( 'readOnlyReason' );
3475
3476                 return is_string( $reason ) ? $reason : false;
3477         }
3478
3479         public function setTableAliases( array $aliases ) {
3480                 $this->tableAliases = $aliases;
3481         }
3482
3483         /**
3484          * @return bool Whether a DB user is required to access the DB
3485          * @since 1.28
3486          */
3487         protected function requiresDatabaseUser() {
3488                 return true;
3489         }
3490
3491         /**
3492          * @since 1.19
3493          * @return string
3494          */
3495         public function __toString() {
3496                 return (string)$this->mConn;
3497         }
3498
3499         /**
3500          * Make sure that copies do not share the same client binding handle
3501          * @throws DBConnectionError
3502          */
3503         public function __clone() {
3504                 $this->connLogger->warning(
3505                         "Cloning " . get_class( $this ) . " is not recomended; forking connection:\n" .
3506                         ( new RuntimeException() )->getTraceAsString()
3507                 );
3508
3509                 if ( $this->isOpen() ) {
3510                         // Open a new connection resource without messing with the old one
3511                         $this->mOpened = false;
3512                         $this->mConn = false;
3513                         $this->mTrxLevel = 0; // no trx anymore
3514                         $this->open( $this->mServer, $this->mUser, $this->mPassword, $this->mDBname );
3515                         $this->lastPing = microtime( true );
3516                 }
3517         }
3518
3519         /**
3520          * Called by serialize. Throw an exception when DB connection is serialized.
3521          * This causes problems on some database engines because the connection is
3522          * not restored on unserialize.
3523          */
3524         public function __sleep() {
3525                 throw new RuntimeException( 'Database serialization may cause problems, since ' .
3526                         'the connection is not restored on wakeup.' );
3527         }
3528
3529         /**
3530          * Run a few simple sanity checks and close dangling connections
3531          */
3532         public function __destruct() {
3533                 if ( $this->mTrxLevel && $this->mTrxDoneWrites ) {
3534                         trigger_error( "Uncommitted DB writes (transaction from {$this->mTrxFname})." );
3535                 }
3536
3537                 $danglingWriters = $this->pendingWriteAndCallbackCallers();
3538                 if ( $danglingWriters ) {
3539                         $fnames = implode( ', ', $danglingWriters );
3540                         trigger_error( "DB transaction writes or callbacks still pending ($fnames)." );
3541                 }
3542
3543                 if ( $this->mConn ) {
3544                         // Avoid connection leaks for sanity
3545                         $this->closeConnection();
3546                         $this->mConn = false;
3547                         $this->mOpened = false;
3548                 }
3549         }
3550 }