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  * Relational database abstraction object
  31  *
  32  * @ingroup Database
  33  * @since 1.28
  34  */
  35 abstract class Database implements IDatabase, IMaintainableDatabase, LoggerAwareInterface {
  36         /** Number of times to re-try an operation in case of deadlock */
  37         const DEADLOCK_TRIES = 4;
  38         /** Minimum time to wait before retry, in microseconds */
  39         const DEADLOCK_DELAY_MIN = 500000;
  40         /** Maximum time to wait before retry */
  41         const DEADLOCK_DELAY_MAX = 1500000;
  42
  43         /** How long before it is worth doing a dummy query to test the connection */
  44         const PING_TTL = 1.0;
  45         const PING_QUERY = 'SELECT 1 AS ping';
  46
  47         const TINY_WRITE_SEC = .010;
  48         const SLOW_WRITE_SEC = .500;
  49         const SMALL_WRITE_ROWS = 100;
  50
  51         /** @var string SQL query */
  52         protected $mLastQuery = '';
  53         /** @var float|bool UNIX timestamp of last write query */
  54         protected $mLastWriteTime = false;
  55         /** @var string|bool */
  56         protected $mPHPError = false;
  57         /** @var string */
  58         protected $mServer;
  59         /** @var string */
  60         protected $mUser;
  61         /** @var string */
  62         protected $mPassword;
  63         /** @var string */
  64         protected $mDBname;
  65         /** @var array[] $aliases Map of (table => (dbname, schema, prefix) map) */
  66         protected $tableAliases = [];
  67         /** @var bool Whether this PHP instance is for a CLI script */
  68         protected $cliMode;
  69         /** @var string Agent name for query profiling */
  70         protected $agent;
  71
  72         /** @var BagOStuff APC cache */
  73         protected $srvCache;
  74         /** @var LoggerInterface */
  75         protected $connLogger;
  76         /** @var LoggerInterface */
  77         protected $queryLogger;
  78         /** @var callback Error logging callback */
  79         protected $errorLogger;
  80
  81         /** @var resource|null Database connection */
  82         protected $mConn = null;
  83         /** @var bool */
  84         protected $mOpened = false;
  85
  86         /** @var array[] List of (callable, method name) */
  87         protected $mTrxIdleCallbacks = [];
  88         /** @var array[] List of (callable, method name) */
  89         protected $mTrxPreCommitCallbacks = [];
  90         /** @var array[] List of (callable, method name) */
  91         protected $mTrxEndCallbacks = [];
  92         /** @var callable[] Map of (name => callable) */
  93         protected $mTrxRecurringCallbacks = [];
  94         /** @var bool Whether to suppress triggering of transaction end callbacks */
  95         protected $mTrxEndCallbacksSuppressed = false;
  96
  97         /** @var string */
  98         protected $mTablePrefix = '';
  99         /** @var string */
 100         protected $mSchema = '';
 101         /** @var integer */
 102         protected $mFlags;
 103         /** @var array */
 104         protected $mLBInfo = [];
 105         /** @var bool|null */
 106         protected $mDefaultBigSelects = null;
 107         /** @var array|bool */
 108         protected $mSchemaVars = false;
 109         /** @var array */
 110         protected $mSessionVars = [];
 111         /** @var array|null */
 112         protected $preparedArgs;
 113         /** @var string|bool|null Stashed value of html_errors INI setting */
 114         protected $htmlErrors;
 115         /** @var string */
 116         protected $delimiter = ';';
 117         /** @var DatabaseDomain */
 118         protected $currentDomain;
 119
 120         /**
 121          * Either 1 if a transaction is active or 0 otherwise.
 122          * The other Trx fields may not be meaningfull if this is 0.
 123          *
 124          * @var int
 125          */
 126         protected $mTrxLevel = 0;
 127         /**
 128          * Either a short hexidecimal string if a transaction is active or ""
 129          *
 130          * @var string
 131          * @see Database::mTrxLevel
 132          */
 133         protected $mTrxShortId = '';
 134         /**
 135          * The UNIX time that the transaction started. Callers can assume that if
 136          * snapshot isolation is used, then the data is *at least* up to date to that
 137          * point (possibly more up-to-date since the first SELECT defines the snapshot).
 138          *
 139          * @var float|null
 140          * @see Database::mTrxLevel
 141          */
 142         private $mTrxTimestamp = null;
 143         /** @var float Lag estimate at the time of BEGIN */
 144         private $mTrxReplicaLag = null;
 145         /**
 146          * Remembers the function name given for starting the most recent transaction via begin().
 147          * Used to provide additional context for error reporting.
 148          *
 149          * @var string
 150          * @see Database::mTrxLevel
 151          */
 152         private $mTrxFname = null;
 153         /**
 154          * Record if possible write queries were done in the last transaction started
 155          *
 156          * @var bool
 157          * @see Database::mTrxLevel
 158          */
 159         private $mTrxDoneWrites = false;
 160         /**
 161          * Record if the current transaction was started implicitly due to DBO_TRX being set.
 162          *
 163          * @var bool
 164          * @see Database::mTrxLevel
 165          */
 166         private $mTrxAutomatic = false;
 167         /**
 168          * Array of levels of atomicity within transactions
 169          *
 170          * @var array
 171          */
 172         private $mTrxAtomicLevels = [];
 173         /**
 174          * Record if the current transaction was started implicitly by Database::startAtomic
 175          *
 176          * @var bool
 177          */
 178         private $mTrxAutomaticAtomic = false;
 179         /**
 180          * Track the write query callers of the current transaction
 181          *
 182          * @var string[]
 183          */
 184         private $mTrxWriteCallers = [];
 185         /**
 186          * @var float Seconds spent in write queries for the current transaction
 187          */
 188         private $mTrxWriteDuration = 0.0;
 189         /**
 190          * @var integer Number of write queries for the current transaction
 191          */
 192         private $mTrxWriteQueryCount = 0;
 193         /**
 194          * @var float Like mTrxWriteQueryCount but excludes lock-bound, easy to replicate, queries
 195          */
 196         private $mTrxWriteAdjDuration = 0.0;
 197         /**
 198          * @var integer Number of write queries counted in mTrxWriteAdjDuration
 199          */
 200         private $mTrxWriteAdjQueryCount = 0;
 201         /**
 202          * @var float RTT time estimate
 203          */
 204         private $mRTTEstimate = 0.0;
 205
 206         /** @var array Map of (name => 1) for locks obtained via lock() */
 207         private $mNamedLocksHeld = [];
 208         /** @var array Map of (table name => 1) for TEMPORARY tables */
 209         protected $mSessionTempTables = [];
 210
 211         /** @var IDatabase|null Lazy handle to the master DB this server replicates from */
 212         private $lazyMasterHandle;
 213
 214         /** @var float UNIX timestamp */
 215         protected $lastPing = 0.0;
 216
 217         /** @var int[] Prior mFlags values */
 218         private $priorFlags = [];
 219
 220         /** @var object|string Class name or object With profileIn/profileOut methods */
 221         protected $profiler;
 222         /** @var TransactionProfiler */
 223         protected $trxProfiler;
 224
 225         /**
 226          * Constructor and database handle and attempt to connect to the DB server
 227          *
 228          * IDatabase classes should not be constructed directly in external
 229          * code. Database::factory() should be used instead.
 230          *
 231          * @param array $params Parameters passed from Database::factory()
 232          */
 233         function __construct( array $params ) {
 234                 $server = $params['host'];
 235                 $user = $params['user'];
 236                 $password = $params['password'];
 237                 $dbName = $params['dbname'];
 238
 239                 $this->mSchema = $params['schema'];
 240                 $this->mTablePrefix = $params['tablePrefix'];
 241
 242                 $this->cliMode = $params['cliMode'];
 243                 // Agent name is added to SQL queries in a comment, so make sure it can't break out
 244                 $this->agent = str_replace( '/', '-', $params['agent'] );
 245
 246                 $this->mFlags = $params['flags'];
 247                 if ( $this->mFlags & self::DBO_DEFAULT ) {
 248                         if ( $this->cliMode ) {
 249                                 $this->mFlags &= ~self::DBO_TRX;
 250                         } else {
 251                                 $this->mFlags |= self::DBO_TRX;
 252                         }
 253                 }
 254
 255                 $this->mSessionVars = $params['variables'];
 256
 257                 $this->srvCache = isset( $params['srvCache'] )
 258                         ? $params['srvCache']
 259                         : new HashBagOStuff();
 260
 261                 $this->profiler = $params['profiler'];
 262                 $this->trxProfiler = $params['trxProfiler'];
 263                 $this->connLogger = $params['connLogger'];
 264                 $this->queryLogger = $params['queryLogger'];
 265                 $this->errorLogger = $params['errorLogger'];
 266
 267                 // Set initial dummy domain until open() sets the final DB/prefix
 268                 $this->currentDomain = DatabaseDomain::newUnspecified();
 269
 270                 if ( $user ) {
 271                         $this->open( $server, $user, $password, $dbName );
 272                 } elseif ( $this->requiresDatabaseUser() ) {
 273                         throw new InvalidArgumentException( "No database user provided." );
 274                 }
 275
 276                 // Set the domain object after open() sets the relevant fields
 277                 if ( $this->mDBname != '' ) {
 278                         // Domains with server scope but a table prefix are not used by IDatabase classes
 279                         $this->currentDomain = new DatabaseDomain( $this->mDBname, null, $this->mTablePrefix );
 280                 }
 281         }
 282
 283         /**
 284          * Construct a Database subclass instance given a database type and parameters
 285          *
 286          * This also connects to the database immediately upon object construction
 287          *
 288          * @param string $dbType A possible DB type (sqlite, mysql, postgres)
 289          * @param array $p Parameter map with keys:
 290          *   - host : The hostname of the DB server
 291          *   - user : The name of the database user the client operates under
 292          *   - password : The password for the database user
 293          *   - dbname : The name of the database to use where queries do not specify one.
 294          *      The database must exist or an error might be thrown. Setting this to the empty string
 295          *      will avoid any such errors and make the handle have no implicit database scope. This is
 296          *      useful for queries like SHOW STATUS, CREATE DATABASE, or DROP DATABASE. Note that a
 297          *      "database" in Postgres is rougly equivalent to an entire MySQL server. This the domain
 298          *      in which user names and such are defined, e.g. users are database-specific in Postgres.
 299          *   - schema : The database schema to use (if supported). A "schema" in Postgres is roughly
 300          *      equivalent to a "database" in MySQL. Note that MySQL and SQLite do not use schemas.
 301          *   - tablePrefix : Optional table prefix that is implicitly added on to all table names
 302          *      recognized in queries. This can be used in place of schemas for handle site farms.
 303          *   - flags : Optional bitfield of DBO_* constants that define connection, protocol,
 304          *      buffering, and transaction behavior. It is STRONGLY adviced to leave the DBO_DEFAULT
 305          *      flag in place UNLESS this this database simply acts as a key/value store.
 306          *   - driver: Optional name of a specific DB client driver. For MySQL, there is the old
 307          *      'mysql' driver and the newer 'mysqli' driver.
 308          *   - variables: Optional map of session variables to set after connecting. This can be
 309          *      used to adjust lock timeouts or encoding modes and the like.
 310          *   - connLogger: Optional PSR-3 logger interface instance.
 311          *   - queryLogger: Optional PSR-3 logger interface instance.
 312          *   - profiler: Optional class name or object with profileIn()/profileOut() methods.
 313          *      These will be called in query(), using a simplified version of the SQL that also
 314          *      includes the agent as a SQL comment.
 315          *   - trxProfiler: Optional TransactionProfiler instance.
 316          *   - errorLogger: Optional callback that takes an Exception and logs it.
 317          *   - cliMode: Whether to consider the execution context that of a CLI script.
 318          *   - agent: Optional name used to identify the end-user in query profiling/logging.
 319          *   - srvCache: Optional BagOStuff instance to an APC-style cache.
 320          * @return Database|null If the database driver or extension cannot be found
 321          * @throws InvalidArgumentException If the database driver or extension cannot be found
 322          * @since 1.18
 323          */
 324         final public static function factory( $dbType, $p = [] ) {
 325                 static $canonicalDBTypes = [
 326                         'mysql' => [ 'mysqli', 'mysql' ],
 327                         'postgres' => [],
 328                         'sqlite' => [],
 329                         'oracle' => [],
 330                         'mssql' => [],
 331                 ];
 332
 333                 $driver = false;
 334                 $dbType = strtolower( $dbType );
 335                 if ( isset( $canonicalDBTypes[$dbType] ) && $canonicalDBTypes[$dbType] ) {
 336                         $possibleDrivers = $canonicalDBTypes[$dbType];
 337                         if ( !empty( $p['driver'] ) ) {
 338                                 if ( in_array( $p['driver'], $possibleDrivers ) ) {
 339                                         $driver = $p['driver'];
 340                                 } else {
 341                                         throw new InvalidArgumentException( __METHOD__ .
 342                                                 " type '$dbType' does not support driver '{$p['driver']}'" );
 343                                 }
 344                         } else {
 345                                 foreach ( $possibleDrivers as $posDriver ) {
 346                                         if ( extension_loaded( $posDriver ) ) {
 347                                                 $driver = $posDriver;
 348                                                 break;
 349                                         }
 350                                 }
 351                         }
 352                 } else {
 353                         $driver = $dbType;
 354                 }
 355                 if ( $driver === false || $driver === '' ) {
 356                         throw new InvalidArgumentException( __METHOD__ .
 357                                 " no viable database extension found for type '$dbType'" );
 358                 }
 359
 360                 $class = 'Database' . ucfirst( $driver );
 361                 if ( class_exists( $class ) && is_subclass_of( $class, 'IDatabase' ) ) {
 362                         // Resolve some defaults for b/c
 363                         $p['host'] = isset( $p['host'] ) ? $p['host'] : false;
 364                         $p['user'] = isset( $p['user'] ) ? $p['user'] : false;
 365                         $p['password'] = isset( $p['password'] ) ? $p['password'] : false;
 366                         $p['dbname'] = isset( $p['dbname'] ) ? $p['dbname'] : false;
 367                         $p['flags'] = isset( $p['flags'] ) ? $p['flags'] : 0;
 368                         $p['variables'] = isset( $p['variables'] ) ? $p['variables'] : [];
 369                         $p['tablePrefix'] = isset( $p['tablePrefix'] ) ? $p['tablePrefix'] : '';
 370                         $p['schema'] = isset( $p['schema'] ) ? $p['schema'] : '';
 371                         $p['cliMode'] = isset( $p['cliMode'] ) ? $p['cliMode'] : ( PHP_SAPI === 'cli' );
 372                         $p['agent'] = isset( $p['agent'] ) ? $p['agent'] : '';
 373                         if ( !isset( $p['connLogger'] ) ) {
 374                                 $p['connLogger'] = new \Psr\Log\NullLogger();
 375                         }
 376                         if ( !isset( $p['queryLogger'] ) ) {
 377                                 $p['queryLogger'] = new \Psr\Log\NullLogger();
 378                         }
 379                         $p['profiler'] = isset( $p['profiler'] ) ? $p['profiler'] : null;
 380                         if ( !isset( $p['trxProfiler'] ) ) {
 381                                 $p['trxProfiler'] = new TransactionProfiler();
 382                         }
 383                         if ( !isset( $p['errorLogger'] ) ) {
 384                                 $p['errorLogger'] = function ( Exception $e ) {
 385                                         trigger_error( get_class( $e ) . ': ' . $e->getMessage(), E_USER_WARNING );
 386                                 };
 387                         }
 388
 389                         $conn = new $class( $p );
 390                 } else {
 391                         $conn = null;
 392                 }
 393
 394                 return $conn;
 395         }
 396
 397         public function setLogger( LoggerInterface $logger ) {
 398                 $this->queryLogger = $logger;
 399         }
 400
 401         public function getServerInfo() {
 402                 return $this->getServerVersion();
 403         }
 404
 405         public function bufferResults( $buffer = null ) {
 406                 $res = !$this->getFlag( self::DBO_NOBUFFER );
 407                 if ( $buffer !== null ) {
 408                         $buffer
 409                                 ? $this->clearFlag( self::DBO_NOBUFFER )
 410                                 : $this->setFlag( self::DBO_NOBUFFER );
 411                 }
 412
 413                 return $res;
 414         }
 415
 416         /**
 417          * Turns on (false) or off (true) the automatic generation and sending
 418          * of a "we're sorry, but there has been a database error" page on
 419          * database errors. Default is on (false). When turned off, the
 420          * code should use lastErrno() and lastError() to handle the
 421          * situation as appropriate.
 422          *
 423          * Do not use this function outside of the Database classes.
 424          *
 425          * @param null|bool $ignoreErrors
 426          * @return bool The previous value of the flag.
 427          */
 428         protected function ignoreErrors( $ignoreErrors = null ) {
 429                 $res = $this->getFlag( self::DBO_IGNORE );
 430                 if ( $ignoreErrors !== null ) {
 431                         $ignoreErrors
 432                                 ? $this->setFlag( self::DBO_IGNORE )
 433                                 : $this->clearFlag( self::DBO_IGNORE );
 434                 }
 435
 436                 return $res;
 437         }
 438
 439         public function trxLevel() {
 440                 return $this->mTrxLevel;
 441         }
 442
 443         public function trxTimestamp() {
 444                 return $this->mTrxLevel ? $this->mTrxTimestamp : null;
 445         }
 446
 447         public function tablePrefix( $prefix = null ) {
 448                 $old = $this->mTablePrefix;
 449                 if ( $prefix !== null ) {
 450                         $this->mTablePrefix = $prefix;
 451                         $this->currentDomain = ( $this->mDBname != '' )
 452                                 ? new DatabaseDomain( $this->mDBname, null, $this->mTablePrefix )
 453                                 : DatabaseDomain::newUnspecified();
 454                 }
 455
 456                 return $old;
 457         }
 458
 459         public function dbSchema( $schema = null ) {
 460                 $old = $this->mSchema;
 461                 if ( $schema !== null ) {
 462                         $this->mSchema = $schema;
 463                 }
 464
 465                 return $old;
 466         }
 467
 468         public function getLBInfo( $name = null ) {
 469                 if ( is_null( $name ) ) {
 470                         return $this->mLBInfo;
 471                 } else {
 472                         if ( array_key_exists( $name, $this->mLBInfo ) ) {
 473                                 return $this->mLBInfo[$name];
 474                         } else {
 475                                 return null;
 476                         }
 477                 }
 478         }
 479
 480         public function setLBInfo( $name, $value = null ) {
 481                 if ( is_null( $value ) ) {
 482                         $this->mLBInfo = $name;
 483                 } else {
 484                         $this->mLBInfo[$name] = $value;
 485                 }
 486         }
 487
 488         public function setLazyMasterHandle( IDatabase $conn ) {
 489                 $this->lazyMasterHandle = $conn;
 490         }
 491
 492         /**
 493          * @return IDatabase|null
 494          * @see setLazyMasterHandle()
 495          * @since 1.27
 496          */
 497         protected function getLazyMasterHandle() {
 498                 return $this->lazyMasterHandle;
 499         }
 500
 501         public function implicitGroupby() {
 502                 return true;
 503         }
 504
 505         public function implicitOrderby() {
 506                 return true;
 507         }
 508
 509         public function lastQuery() {
 510                 return $this->mLastQuery;
 511         }
 512
 513         public function doneWrites() {
 514                 return (bool)$this->mLastWriteTime;
 515         }
 516
 517         public function lastDoneWrites() {
 518                 return $this->mLastWriteTime ?: false;
 519         }
 520
 521         public function writesPending() {
 522                 return $this->mTrxLevel && $this->mTrxDoneWrites;
 523         }
 524
 525         public function writesOrCallbacksPending() {
 526                 return $this->mTrxLevel && (
 527                         $this->mTrxDoneWrites || $this->mTrxIdleCallbacks || $this->mTrxPreCommitCallbacks
 528                 );
 529         }
 530
 531         public function pendingWriteQueryDuration( $type = self::ESTIMATE_TOTAL ) {
 532                 if ( !$this->mTrxLevel ) {
 533                         return false;
 534                 } elseif ( !$this->mTrxDoneWrites ) {
 535                         return 0.0;
 536                 }
 537
 538                 switch ( $type ) {
 539                         case self::ESTIMATE_DB_APPLY:
 540                                 $this->ping( $rtt );
 541                                 $rttAdjTotal = $this->mTrxWriteAdjQueryCount * $rtt;
 542                                 $applyTime = max( $this->mTrxWriteAdjDuration - $rttAdjTotal, 0 );
 543                                 // For omitted queries, make them count as something at least
 544                                 $omitted = $this->mTrxWriteQueryCount - $this->mTrxWriteAdjQueryCount;
 545                                 $applyTime += self::TINY_WRITE_SEC * $omitted;
 546
 547                                 return $applyTime;
 548                         default: // everything
 549                                 return $this->mTrxWriteDuration;
 550                 }
 551         }
 552
 553         public function pendingWriteCallers() {
 554                 return $this->mTrxLevel ? $this->mTrxWriteCallers : [];
 555         }
 556
 557         protected function pendingWriteAndCallbackCallers() {
 558                 if ( !$this->mTrxLevel ) {
 559                         return [];
 560                 }
 561
 562                 $fnames = $this->mTrxWriteCallers;
 563                 foreach ( [
 564                         $this->mTrxIdleCallbacks,
 565                         $this->mTrxPreCommitCallbacks,
 566                         $this->mTrxEndCallbacks
 567                 ] as $callbacks ) {
 568                         foreach ( $callbacks as $callback ) {
 569                                 $fnames[] = $callback[1];
 570                         }
 571                 }
 572
 573                 return $fnames;
 574         }
 575
 576         public function isOpen() {
 577                 return $this->mOpened;
 578         }
 579
 580         public function setFlag( $flag, $remember = self::REMEMBER_NOTHING ) {
 581                 if ( $remember === self::REMEMBER_PRIOR ) {
 582                         array_push( $this->priorFlags, $this->mFlags );
 583                 }
 584                 $this->mFlags |= $flag;
 585         }
 586
 587         public function clearFlag( $flag, $remember = self::REMEMBER_NOTHING ) {
 588                 if ( $remember === self::REMEMBER_PRIOR ) {
 589                         array_push( $this->priorFlags, $this->mFlags );
 590                 }
 591                 $this->mFlags &= ~$flag;
 592         }
 593
 594         public function restoreFlags( $state = self::RESTORE_PRIOR ) {
 595                 if ( !$this->priorFlags ) {
 596                         return;
 597                 }
 598
 599                 if ( $state === self::RESTORE_INITIAL ) {
 600                         $this->mFlags = reset( $this->priorFlags );
 601                         $this->priorFlags = [];
 602                 } else {
 603                         $this->mFlags = array_pop( $this->priorFlags );
 604                 }
 605         }
 606
 607         public function getFlag( $flag ) {
 608                 return !!( $this->mFlags & $flag );
 609         }
 610
 611         public function getProperty( $name ) {
 612                 return $this->$name;
 613         }
 614
 615         public function getDomainID() {
 616                 return $this->currentDomain->getId();
 617         }
 618
 619         final public function getWikiID() {
 620                 return $this->getDomainID();
 621         }
 622
 623         /**
 624          * Get information about an index into an object
 625          * @param string $table Table name
 626          * @param string $index Index name
 627          * @param string $fname Calling function name
 628          * @return mixed Database-specific index description class or false if the index does not exist
 629          */
 630         abstract function indexInfo( $table, $index, $fname = __METHOD__ );
 631
 632         /**
 633          * Wrapper for addslashes()
 634          *
 635          * @param string $s String to be slashed.
 636          * @return string Slashed string.
 637          */
 638         abstract function strencode( $s );
 639
 640         protected function installErrorHandler() {
 641                 $this->mPHPError = false;
 642                 $this->htmlErrors = ini_set( 'html_errors', '0' );
 643                 set_error_handler( [ $this, 'connectionErrorLogger' ] );
 644         }
 645
 646         /**
 647          * @return bool|string
 648          */
 649         protected function restoreErrorHandler() {
 650                 restore_error_handler();
 651                 if ( $this->htmlErrors !== false ) {
 652                         ini_set( 'html_errors', $this->htmlErrors );
 653                 }
 654                 if ( $this->mPHPError ) {
 655                         $error = preg_replace( '!\[<a.*</a>\]!', '', $this->mPHPError );
 656                         $error = preg_replace( '!^.*?:\s?(.*)$!', '$1', $error );
 657
 658                         return $error;
 659                 } else {
 660                         return false;
 661                 }
 662         }
 663
 664         /**
 665          * This method should not be used outside of Database classes
 666          *
 667          * @param int $errno
 668          * @param string $errstr
 669          */
 670         public function connectionErrorLogger( $errno, $errstr ) {
 671                 $this->mPHPError = $errstr;
 672         }
 673
 674         /**
 675          * Create a log context to pass to PSR-3 logger functions.
 676          *
 677          * @param array $extras Additional data to add to context
 678          * @return array
 679          */
 680         protected function getLogContext( array $extras = [] ) {
 681                 return array_merge(
 682                         [
 683                                 'db_server' => $this->mServer,
 684                                 'db_name' => $this->mDBname,
 685                                 'db_user' => $this->mUser,
 686                         ],
 687                         $extras
 688                 );
 689         }
 690
 691         public function close() {
 692                 if ( $this->mConn ) {
 693                         if ( $this->trxLevel() ) {
 694                                 $this->commit( __METHOD__, self::FLUSHING_INTERNAL );
 695                         }
 696
 697                         $closed = $this->closeConnection();
 698                         $this->mConn = false;
 699                 } elseif ( $this->mTrxIdleCallbacks || $this->mTrxEndCallbacks ) { // sanity
 700                         throw new RuntimeException( "Transaction callbacks still pending." );
 701                 } else {
 702                         $closed = true;
 703                 }
 704                 $this->mOpened = false;
 705
 706                 return $closed;
 707         }
 708
 709         /**
 710          * Make sure isOpen() returns true as a sanity check
 711          *
 712          * @throws DBUnexpectedError
 713          */
 714         protected function assertOpen() {
 715                 if ( !$this->isOpen() ) {
 716                         throw new DBUnexpectedError( $this, "DB connection was already closed." );
 717                 }
 718         }
 719
 720         /**
 721          * Closes underlying database connection
 722          * @since 1.20
 723          * @return bool Whether connection was closed successfully
 724          */
 725         abstract protected function closeConnection();
 726
 727         public function reportConnectionError( $error = 'Unknown error' ) {
 728                 $myError = $this->lastError();
 729                 if ( $myError ) {
 730                         $error = $myError;
 731                 }
 732
 733                 # New method
 734                 throw new DBConnectionError( $this, $error );
 735         }
 736
 737         /**
 738          * The DBMS-dependent part of query()
 739          *
 740          * @param string $sql SQL query.
 741          * @return ResultWrapper|bool Result object to feed to fetchObject,
 742          *   fetchRow, ...; or false on failure
 743          */
 744         abstract protected function doQuery( $sql );
 745
 746         /**
 747          * Determine whether a query writes to the DB.
 748          * Should return true if unsure.
 749          *
 750          * @param string $sql
 751          * @return bool
 752          */
 753         protected function isWriteQuery( $sql ) {
 754                 return !preg_match(
 755                         '/^(?:SELECT|BEGIN|ROLLBACK|COMMIT|SET|SHOW|EXPLAIN|\(SELECT)\b/i', $sql );
 756         }
 757
 758         /**
 759          * @param $sql
 760          * @return string|null
 761          */
 762         protected function getQueryVerb( $sql ) {
 763                 return preg_match( '/^\s*([a-z]+)/i', $sql, $m ) ? strtoupper( $m[1] ) : null;
 764         }
 765
 766         /**
 767          * Determine whether a SQL statement is sensitive to isolation level.
 768          * A SQL statement is considered transactable if its result could vary
 769          * depending on the transaction isolation level. Operational commands
 770          * such as 'SET' and 'SHOW' are not considered to be transactable.
 771          *
 772          * @param string $sql
 773          * @return bool
 774          */
 775         protected function isTransactableQuery( $sql ) {
 776                 return !in_array(
 777                         $this->getQueryVerb( $sql ),
 778                         [ 'BEGIN', 'COMMIT', 'ROLLBACK', 'SHOW', 'SET', 'CREATE', 'ALTER' ],
 779                         true
 780                 );
 781         }
 782
 783         /**
 784          * @param string $sql A SQL query
 785          * @return bool Whether $sql is SQL for creating/dropping a new TEMPORARY table
 786          */
 787         protected function registerTempTableOperation( $sql ) {
 788                 if ( preg_match(
 789                         '/^CREATE\s+TEMPORARY\s+TABLE\s+(?:IF\s+NOT\s+EXISTS\s+)?[`"\']?(\w+)[`"\']?/i',
 790                         $sql,
 791                         $matches
 792                 ) ) {
 793                         $this->mSessionTempTables[$matches[1]] = 1;
 794
 795                         return true;
 796                 } elseif ( preg_match(
 797                         '/^DROP\s+(?:TEMPORARY\s+)?TABLE\s+(?:IF\s+EXISTS\s+)?[`"\']?(\w+)[`"\']?/i',
 798                         $sql,
 799                         $matches
 800                 ) ) {
 801                         unset( $this->mSessionTempTables[$matches[1]] );
 802
 803                         return true;
 804                 } elseif ( preg_match(
 805                         '/^(?:INSERT\s+(?:\w+\s+)?INTO|UPDATE|DELETE\s+FROM)\s+[`"\']?(\w+)[`"\']?/i',
 806                         $sql,
 807                         $matches
 808                 ) ) {
 809                         return isset( $this->mSessionTempTables[$matches[1]] );
 810                 }
 811
 812                 return false;
 813         }
 814
 815         public function query( $sql, $fname = __METHOD__, $tempIgnore = false ) {
 816                 $priorWritesPending = $this->writesOrCallbacksPending();
 817                 $this->mLastQuery = $sql;
 818
 819                 $isWrite = $this->isWriteQuery( $sql ) && !$this->registerTempTableOperation( $sql );
 820                 if ( $isWrite ) {
 821                         $reason = $this->getReadOnlyReason();
 822                         if ( $reason !== false ) {
 823                                 throw new DBReadOnlyError( $this, "Database is read-only: $reason" );
 824                         }
 825                         # Set a flag indicating that writes have been done
 826                         $this->mLastWriteTime = microtime( true );
 827                 }
 828
 829                 // Add trace comment to the begin of the sql string, right after the operator.
 830                 // Or, for one-word queries (like "BEGIN" or COMMIT") add it to the end (bug 42598)
 831                 $commentedSql = preg_replace( '/\s|$/', " /* $fname {$this->agent} */ ", $sql, 1 );
 832
 833                 # Start implicit transactions that wrap the request if DBO_TRX is enabled
 834                 if ( !$this->mTrxLevel && $this->getFlag( self::DBO_TRX )
 835                         && $this->isTransactableQuery( $sql )
 836                 ) {
 837                         $this->begin( __METHOD__ . " ($fname)", self::TRANSACTION_INTERNAL );
 838                         $this->mTrxAutomatic = true;
 839                 }
 840
 841                 # Keep track of whether the transaction has write queries pending
 842                 if ( $this->mTrxLevel && !$this->mTrxDoneWrites && $isWrite ) {
 843                         $this->mTrxDoneWrites = true;
 844                         $this->trxProfiler->transactionWritingIn(
 845                                 $this->mServer, $this->mDBname, $this->mTrxShortId );
 846                 }
 847
 848                 if ( $this->getFlag( self::DBO_DEBUG ) ) {
 849                         $this->queryLogger->debug( "{$this->mDBname} {$commentedSql}" );
 850                 }
 851
 852                 # Avoid fatals if close() was called
 853                 $this->assertOpen();
 854
 855                 # Send the query to the server
 856                 $ret = $this->doProfiledQuery( $sql, $commentedSql, $isWrite, $fname );
 857
 858                 # Try reconnecting if the connection was lost
 859                 if ( false === $ret && $this->wasErrorReissuable() ) {
 860                         $recoverable = $this->canRecoverFromDisconnect( $sql, $priorWritesPending );
 861                         # Stash the last error values before anything might clear them
 862                         $lastError = $this->lastError();
 863                         $lastErrno = $this->lastErrno();
 864                         # Update state tracking to reflect transaction loss due to disconnection
 865                         $this->handleSessionLoss();
 866                         if ( $this->reconnect() ) {
 867                                 $msg = __METHOD__ . ": lost connection to {$this->getServer()}; reconnected";
 868                                 $this->connLogger->warning( $msg );
 869                                 $this->queryLogger->warning(
 870                                         "$msg:\n" . ( new RuntimeException() )->getTraceAsString() );
 871
 872                                 if ( !$recoverable ) {
 873                                         # Callers may catch the exception and continue to use the DB
 874                                         $this->reportQueryError( $lastError, $lastErrno, $sql, $fname );
 875                                 } else {
 876                                         # Should be safe to silently retry the query
 877                                         $ret = $this->doProfiledQuery( $sql, $commentedSql, $isWrite, $fname );
 878                                 }
 879                         } else {
 880                                 $msg = __METHOD__ . ": lost connection to {$this->getServer()} permanently";
 881                                 $this->connLogger->error( $msg );
 882                         }
 883                 }
 884
 885                 if ( false === $ret ) {
 886                         # Deadlocks cause the entire transaction to abort, not just the statement.
 887                         # http://dev.mysql.com/doc/refman/5.7/en/innodb-error-handling.html
 888                         # https://www.postgresql.org/docs/9.1/static/explicit-locking.html
 889                         if ( $this->wasDeadlock() ) {
 890                                 if ( $this->explicitTrxActive() || $priorWritesPending ) {
 891                                         $tempIgnore = false; // not recoverable
 892                                 }
 893                                 # Update state tracking to reflect transaction loss
 894                                 $this->handleSessionLoss();
 895                         }
 896
 897                         $this->reportQueryError(
 898                                 $this->lastError(), $this->lastErrno(), $sql, $fname, $tempIgnore );
 899                 }
 900
 901                 $res = $this->resultObject( $ret );
 902
 903                 return $res;
 904         }
 905
 906         private function doProfiledQuery( $sql, $commentedSql, $isWrite, $fname ) {
 907                 $isMaster = !is_null( $this->getLBInfo( 'master' ) );
 908                 # generalizeSQL() will probably cut down the query to reasonable
 909                 # logging size most of the time. The substr is really just a sanity check.
 910                 if ( $isMaster ) {
 911                         $queryProf = 'query-m: ' . substr( self::generalizeSQL( $sql ), 0, 255 );
 912                 } else {
 913                         $queryProf = 'query: ' . substr( self::generalizeSQL( $sql ), 0, 255 );
 914                 }
 915
 916                 # Include query transaction state
 917                 $queryProf .= $this->mTrxShortId ? " [TRX#{$this->mTrxShortId}]" : "";
 918
 919                 $startTime = microtime( true );
 920                 if ( $this->profiler ) {
 921                         call_user_func( [ $this->profiler, 'profileIn' ], $queryProf );
 922                 }
 923                 $ret = $this->doQuery( $commentedSql );
 924                 if ( $this->profiler ) {
 925                         call_user_func( [ $this->profiler, 'profileOut' ], $queryProf );
 926                 }
 927                 $queryRuntime = max( microtime( true ) - $startTime, 0.0 );
 928
 929                 unset( $queryProfSection ); // profile out (if set)
 930
 931                 if ( $ret !== false ) {
 932                         $this->lastPing = $startTime;
 933                         if ( $isWrite && $this->mTrxLevel ) {
 934                                 $this->updateTrxWriteQueryTime( $sql, $queryRuntime );
 935                                 $this->mTrxWriteCallers[] = $fname;
 936                         }
 937                 }
 938
 939                 if ( $sql === self::PING_QUERY ) {
 940                         $this->mRTTEstimate = $queryRuntime;
 941                 }
 942
 943                 $this->trxProfiler->recordQueryCompletion(
 944                         $queryProf, $startTime, $isWrite, $this->affectedRows()
 945                 );
 946                 $this->queryLogger->debug( $sql, [
 947                         'method' => $fname,
 948                         'master' => $isMaster,
 949                         'runtime' => $queryRuntime,
 950                 ] );
 951
 952                 return $ret;
 953         }
 954
 955         /**
 956          * Update the estimated run-time of a query, not counting large row lock times
 957          *
 958          * LoadBalancer can be set to rollback transactions that will create huge replication
 959          * lag. It bases this estimate off of pendingWriteQueryDuration(). Certain simple
 960          * queries, like inserting a row can take a long time due to row locking. This method
 961          * uses some simple heuristics to discount those cases.
 962          *
 963          * @param string $sql A SQL write query
 964          * @param float $runtime Total runtime, including RTT
 965          */
 966         private function updateTrxWriteQueryTime( $sql, $runtime ) {
 967                 // Whether this is indicative of replica DB runtime (except for RBR or ws_repl)
 968                 $indicativeOfReplicaRuntime = true;
 969                 if ( $runtime > self::SLOW_WRITE_SEC ) {
 970                         $verb = $this->getQueryVerb( $sql );
 971                         // insert(), upsert(), replace() are fast unless bulky in size or blocked on locks
 972                         if ( $verb === 'INSERT' ) {
 973                                 $indicativeOfReplicaRuntime = $this->affectedRows() > self::SMALL_WRITE_ROWS;
 974                         } elseif ( $verb === 'REPLACE' ) {
 975                                 $indicativeOfReplicaRuntime = $this->affectedRows() > self::SMALL_WRITE_ROWS / 2;
 976                         }
 977                 }
 978
 979                 $this->mTrxWriteDuration += $runtime;
 980                 $this->mTrxWriteQueryCount += 1;
 981                 if ( $indicativeOfReplicaRuntime ) {
 982                         $this->mTrxWriteAdjDuration += $runtime;
 983                         $this->mTrxWriteAdjQueryCount += 1;
 984                 }
 985         }
 986
 987         private function canRecoverFromDisconnect( $sql, $priorWritesPending ) {
 988                 # Transaction dropped; this can mean lost writes, or REPEATABLE-READ snapshots.
 989                 # Dropped connections also mean that named locks are automatically released.
 990                 # Only allow error suppression in autocommit mode or when the lost transaction
 991                 # didn't matter anyway (aside from DBO_TRX snapshot loss).
 992                 if ( $this->mNamedLocksHeld ) {
 993                         return false; // possible critical section violation
 994                 } elseif ( $sql === 'COMMIT' ) {
 995                         return !$priorWritesPending; // nothing written anyway? (T127428)
 996                 } elseif ( $sql === 'ROLLBACK' ) {
 997                         return true; // transaction lost...which is also what was requested :)
 998                 } elseif ( $this->explicitTrxActive() ) {
 999                         return false; // don't drop atomocity
1000                 } elseif ( $priorWritesPending ) {
1001                         return false; // prior writes lost from implicit transaction
1002                 }
1003
1004                 return true;
1005         }
1006
1007         private function handleSessionLoss() {
1008                 $this->mTrxLevel = 0;
1009                 $this->mTrxIdleCallbacks = []; // bug 65263
1010                 $this->mTrxPreCommitCallbacks = []; // bug 65263
1011                 $this->mSessionTempTables = [];
1012                 $this->mNamedLocksHeld = [];
1013                 try {
1014                         // Handle callbacks in mTrxEndCallbacks
1015                         $this->runOnTransactionIdleCallbacks( self::TRIGGER_ROLLBACK );
1016                         $this->runTransactionListenerCallbacks( self::TRIGGER_ROLLBACK );
1017                         return null;
1018                 } catch ( Exception $e ) {
1019                         // Already logged; move on...
1020                         return $e;
1021                 }
1022         }
1023
1024         public function reportQueryError( $error, $errno, $sql, $fname, $tempIgnore = false ) {
1025                 if ( $this->ignoreErrors() || $tempIgnore ) {
1026                         $this->queryLogger->debug( "SQL ERROR (ignored): $error\n" );
1027                 } else {
1028                         $sql1line = mb_substr( str_replace( "\n", "\\n", $sql ), 0, 5 * 1024 );
1029                         $this->queryLogger->error(
1030                                 "{fname}\t{db_server}\t{errno}\t{error}\t{sql1line}",
1031                                 $this->getLogContext( [
1032                                         'method' => __METHOD__,
1033                                         'errno' => $errno,
1034                                         'error' => $error,
1035                                         'sql1line' => $sql1line,
1036                                         'fname' => $fname,
1037                                 ] )
1038                         );
1039                         $this->queryLogger->debug( "SQL ERROR: " . $error . "\n" );
1040                         throw new DBQueryError( $this, $error, $errno, $sql, $fname );
1041                 }
1042         }
1043
1044         public function freeResult( $res ) {
1045         }
1046
1047         public function selectField(
1048                 $table, $var, $cond = '', $fname = __METHOD__, $options = []
1049         ) {
1050                 if ( $var === '*' ) { // sanity
1051                         throw new DBUnexpectedError( $this, "Cannot use a * field: got '$var'" );
1052                 }
1053
1054                 if ( !is_array( $options ) ) {
1055                         $options = [ $options ];
1056                 }
1057
1058                 $options['LIMIT'] = 1;
1059
1060                 $res = $this->select( $table, $var, $cond, $fname, $options );
1061                 if ( $res === false || !$this->numRows( $res ) ) {
1062                         return false;
1063                 }
1064
1065                 $row = $this->fetchRow( $res );
1066
1067                 if ( $row !== false ) {
1068                         return reset( $row );
1069                 } else {
1070                         return false;
1071                 }
1072         }
1073
1074         public function selectFieldValues(
1075                 $table, $var, $cond = '', $fname = __METHOD__, $options = [], $join_conds = []
1076         ) {
1077                 if ( $var === '*' ) { // sanity
1078                         throw new DBUnexpectedError( $this, "Cannot use a * field" );
1079                 } elseif ( !is_string( $var ) ) { // sanity
1080                         throw new DBUnexpectedError( $this, "Cannot use an array of fields" );
1081                 }
1082
1083                 if ( !is_array( $options ) ) {
1084                         $options = [ $options ];
1085                 }
1086
1087                 $res = $this->select( $table, $var, $cond, $fname, $options, $join_conds );
1088                 if ( $res === false ) {
1089                         return false;
1090                 }
1091
1092                 $values = [];
1093                 foreach ( $res as $row ) {
1094                         $values[] = $row->$var;
1095                 }
1096
1097                 return $values;
1098         }
1099
1100         /**
1101          * Returns an optional USE INDEX clause to go after the table, and a
1102          * string to go at the end of the query.
1103          *
1104          * @param array $options Associative array of options to be turned into
1105          *   an SQL query, valid keys are listed in the function.
1106          * @return array
1107          * @see Database::select()
1108          */
1109         protected function makeSelectOptions( $options ) {
1110                 $preLimitTail = $postLimitTail = '';
1111                 $startOpts = '';
1112
1113                 $noKeyOptions = [];
1114
1115                 foreach ( $options as $key => $option ) {
1116                         if ( is_numeric( $key ) ) {
1117                                 $noKeyOptions[$option] = true;
1118                         }
1119                 }
1120
1121                 $preLimitTail .= $this->makeGroupByWithHaving( $options );
1122
1123                 $preLimitTail .= $this->makeOrderBy( $options );
1124
1125                 // if (isset($options['LIMIT'])) {
1126                 //      $tailOpts .= $this->limitResult('', $options['LIMIT'],
1127                 //              isset($options['OFFSET']) ? $options['OFFSET']
1128                 //              : false);
1129                 // }
1130
1131                 if ( isset( $noKeyOptions['FOR UPDATE'] ) ) {
1132                         $postLimitTail .= ' FOR UPDATE';
1133                 }
1134
1135                 if ( isset( $noKeyOptions['LOCK IN SHARE MODE'] ) ) {
1136                         $postLimitTail .= ' LOCK IN SHARE MODE';
1137                 }
1138
1139                 if ( isset( $noKeyOptions['DISTINCT'] ) || isset( $noKeyOptions['DISTINCTROW'] ) ) {
1140                         $startOpts .= 'DISTINCT';
1141                 }
1142
1143                 # Various MySQL extensions
1144                 if ( isset( $noKeyOptions['STRAIGHT_JOIN'] ) ) {
1145                         $startOpts .= ' /*! STRAIGHT_JOIN */';
1146                 }
1147
1148                 if ( isset( $noKeyOptions['HIGH_PRIORITY'] ) ) {
1149                         $startOpts .= ' HIGH_PRIORITY';
1150                 }
1151
1152                 if ( isset( $noKeyOptions['SQL_BIG_RESULT'] ) ) {
1153                         $startOpts .= ' SQL_BIG_RESULT';
1154                 }
1155
1156                 if ( isset( $noKeyOptions['SQL_BUFFER_RESULT'] ) ) {
1157                         $startOpts .= ' SQL_BUFFER_RESULT';
1158                 }
1159
1160                 if ( isset( $noKeyOptions['SQL_SMALL_RESULT'] ) ) {
1161                         $startOpts .= ' SQL_SMALL_RESULT';
1162                 }
1163
1164                 if ( isset( $noKeyOptions['SQL_CALC_FOUND_ROWS'] ) ) {
1165                         $startOpts .= ' SQL_CALC_FOUND_ROWS';
1166                 }
1167
1168                 if ( isset( $noKeyOptions['SQL_CACHE'] ) ) {
1169                         $startOpts .= ' SQL_CACHE';
1170                 }
1171
1172                 if ( isset( $noKeyOptions['SQL_NO_CACHE'] ) ) {
1173                         $startOpts .= ' SQL_NO_CACHE';
1174                 }
1175
1176                 if ( isset( $options['USE INDEX'] ) && is_string( $options['USE INDEX'] ) ) {
1177                         $useIndex = $this->useIndexClause( $options['USE INDEX'] );
1178                 } else {
1179                         $useIndex = '';
1180                 }
1181                 if ( isset( $options['IGNORE INDEX'] ) && is_string( $options['IGNORE INDEX'] ) ) {
1182                         $ignoreIndex = $this->ignoreIndexClause( $options['IGNORE INDEX'] );
1183                 } else {
1184                         $ignoreIndex = '';
1185                 }
1186
1187                 return [ $startOpts, $useIndex, $preLimitTail, $postLimitTail, $ignoreIndex ];
1188         }
1189
1190         /**
1191          * Returns an optional GROUP BY with an optional HAVING
1192          *
1193          * @param array $options Associative array of options
1194          * @return string
1195          * @see Database::select()
1196          * @since 1.21
1197          */
1198         protected function makeGroupByWithHaving( $options ) {
1199                 $sql = '';
1200                 if ( isset( $options['GROUP BY'] ) ) {
1201                         $gb = is_array( $options['GROUP BY'] )
1202                                 ? implode( ',', $options['GROUP BY'] )
1203                                 : $options['GROUP BY'];
1204                         $sql .= ' GROUP BY ' . $gb;
1205                 }
1206                 if ( isset( $options['HAVING'] ) ) {
1207                         $having = is_array( $options['HAVING'] )
1208                                 ? $this->makeList( $options['HAVING'], self::LIST_AND )
1209                                 : $options['HAVING'];
1210                         $sql .= ' HAVING ' . $having;
1211                 }
1212
1213                 return $sql;
1214         }
1215
1216         /**
1217          * Returns an optional ORDER BY
1218          *
1219          * @param array $options Associative array of options
1220          * @return string
1221          * @see Database::select()
1222          * @since 1.21
1223          */
1224         protected function makeOrderBy( $options ) {
1225                 if ( isset( $options['ORDER BY'] ) ) {
1226                         $ob = is_array( $options['ORDER BY'] )
1227                                 ? implode( ',', $options['ORDER BY'] )
1228                                 : $options['ORDER BY'];
1229
1230                         return ' ORDER BY ' . $ob;
1231                 }
1232
1233                 return '';
1234         }
1235
1236         public function select( $table, $vars, $conds = '', $fname = __METHOD__,
1237                 $options = [], $join_conds = [] ) {
1238                 $sql = $this->selectSQLText( $table, $vars, $conds, $fname, $options, $join_conds );
1239
1240                 return $this->query( $sql, $fname );
1241         }
1242
1243         public function selectSQLText( $table, $vars, $conds = '', $fname = __METHOD__,
1244                 $options = [], $join_conds = []
1245         ) {
1246                 if ( is_array( $vars ) ) {
1247                         $vars = implode( ',', $this->fieldNamesWithAlias( $vars ) );
1248                 }
1249
1250                 $options = (array)$options;
1251                 $useIndexes = ( isset( $options['USE INDEX'] ) && is_array( $options['USE INDEX'] ) )
1252                         ? $options['USE INDEX']
1253                         : [];
1254                 $ignoreIndexes = (
1255                         isset( $options['IGNORE INDEX'] ) &&
1256                         is_array( $options['IGNORE INDEX'] )
1257                 )
1258                         ? $options['IGNORE INDEX']
1259                         : [];
1260
1261                 if ( is_array( $table ) ) {
1262                         $from = ' FROM ' .
1263                                 $this->tableNamesWithIndexClauseOrJOIN(
1264                                         $table, $useIndexes, $ignoreIndexes, $join_conds );
1265                 } elseif ( $table != '' ) {
1266                         if ( $table[0] == ' ' ) {
1267                                 $from = ' FROM ' . $table;
1268                         } else {
1269                                 $from = ' FROM ' .
1270                                         $this->tableNamesWithIndexClauseOrJOIN(
1271                                                 [ $table ], $useIndexes, $ignoreIndexes, [] );
1272                         }
1273                 } else {
1274                         $from = '';
1275                 }
1276
1277                 list( $startOpts, $useIndex, $preLimitTail, $postLimitTail, $ignoreIndex ) =
1278                         $this->makeSelectOptions( $options );
1279
1280                 if ( !empty( $conds ) ) {
1281                         if ( is_array( $conds ) ) {
1282                                 $conds = $this->makeList( $conds, self::LIST_AND );
1283                         }
1284                         $sql = "SELECT $startOpts $vars $from $useIndex $ignoreIndex " .
1285                                 "WHERE $conds $preLimitTail";
1286                 } else {
1287                         $sql = "SELECT $startOpts $vars $from $useIndex $ignoreIndex $preLimitTail";
1288                 }
1289
1290                 if ( isset( $options['LIMIT'] ) ) {
1291                         $sql = $this->limitResult( $sql, $options['LIMIT'],
1292                                 isset( $options['OFFSET'] ) ? $options['OFFSET'] : false );
1293                 }
1294                 $sql = "$sql $postLimitTail";
1295
1296                 if ( isset( $options['EXPLAIN'] ) ) {
1297                         $sql = 'EXPLAIN ' . $sql;
1298                 }
1299
1300                 return $sql;
1301         }
1302
1303         public function selectRow( $table, $vars, $conds, $fname = __METHOD__,
1304                 $options = [], $join_conds = []
1305         ) {
1306                 $options = (array)$options;
1307                 $options['LIMIT'] = 1;
1308                 $res = $this->select( $table, $vars, $conds, $fname, $options, $join_conds );
1309
1310                 if ( $res === false ) {
1311                         return false;
1312                 }
1313
1314                 if ( !$this->numRows( $res ) ) {
1315                         return false;
1316                 }
1317
1318                 $obj = $this->fetchObject( $res );
1319
1320                 return $obj;
1321         }
1322
1323         public function estimateRowCount(
1324                 $table, $vars = '*', $conds = '', $fname = __METHOD__, $options = []
1325         ) {
1326                 $rows = 0;
1327                 $res = $this->select( $table, [ 'rowcount' => 'COUNT(*)' ], $conds, $fname, $options );
1328
1329                 if ( $res ) {
1330                         $row = $this->fetchRow( $res );
1331                         $rows = ( isset( $row['rowcount'] ) ) ? (int)$row['rowcount'] : 0;
1332                 }
1333
1334                 return $rows;
1335         }
1336
1337         public function selectRowCount(
1338                 $tables, $vars = '*', $conds = '', $fname = __METHOD__, $options = [], $join_conds = []
1339         ) {
1340                 $rows = 0;
1341                 $sql = $this->selectSQLText( $tables, '1', $conds, $fname, $options, $join_conds );
1342                 $res = $this->query( "SELECT COUNT(*) AS rowcount FROM ($sql) tmp_count", $fname );
1343
1344                 if ( $res ) {
1345                         $row = $this->fetchRow( $res );
1346                         $rows = ( isset( $row['rowcount'] ) ) ? (int)$row['rowcount'] : 0;
1347                 }
1348
1349                 return $rows;
1350         }
1351
1352         /**
1353          * Removes most variables from an SQL query and replaces them with X or N for numbers.
1354          * It's only slightly flawed. Don't use for anything important.
1355          *
1356          * @param string $sql A SQL Query
1357          *
1358          * @return string
1359          */
1360         protected static function generalizeSQL( $sql ) {
1361                 # This does the same as the regexp below would do, but in such a way
1362                 # as to avoid crashing php on some large strings.
1363                 # $sql = preg_replace( "/'([^\\\\']|\\\\.)*'|\"([^\\\\\"]|\\\\.)*\"/", "'X'", $sql );
1364
1365                 $sql = str_replace( "\\\\", '', $sql );
1366                 $sql = str_replace( "\\'", '', $sql );
1367                 $sql = str_replace( "\\\"", '', $sql );
1368                 $sql = preg_replace( "/'.*'/s", "'X'", $sql );
1369                 $sql = preg_replace( '/".*"/s', "'X'", $sql );
1370
1371                 # All newlines, tabs, etc replaced by single space
1372                 $sql = preg_replace( '/\s+/', ' ', $sql );
1373
1374                 # All numbers => N,
1375                 # except the ones surrounded by characters, e.g. l10n
1376                 $sql = preg_replace( '/-?\d+(,-?\d+)+/s', 'N,...,N', $sql );
1377                 $sql = preg_replace( '/(?<![a-zA-Z])-?\d+(?![a-zA-Z])/s', 'N', $sql );
1378
1379                 return $sql;
1380         }
1381
1382         public function fieldExists( $table, $field, $fname = __METHOD__ ) {
1383                 $info = $this->fieldInfo( $table, $field );
1384
1385                 return (bool)$info;
1386         }
1387
1388         public function indexExists( $table, $index, $fname = __METHOD__ ) {
1389                 if ( !$this->tableExists( $table ) ) {
1390                         return null;
1391                 }
1392
1393                 $info = $this->indexInfo( $table, $index, $fname );
1394                 if ( is_null( $info ) ) {
1395                         return null;
1396                 } else {
1397                         return $info !== false;
1398                 }
1399         }
1400
1401         public function tableExists( $table, $fname = __METHOD__ ) {
1402                 $tableRaw = $this->tableName( $table, 'raw' );
1403                 if ( isset( $this->mSessionTempTables[$tableRaw] ) ) {
1404                         return true; // already known to exist
1405                 }
1406
1407                 $table = $this->tableName( $table );
1408                 $old = $this->ignoreErrors( true );
1409                 $res = $this->query( "SELECT 1 FROM $table LIMIT 1", $fname );
1410                 $this->ignoreErrors( $old );
1411
1412                 return (bool)$res;
1413         }
1414
1415         public function indexUnique( $table, $index ) {
1416                 $indexInfo = $this->indexInfo( $table, $index );
1417
1418                 if ( !$indexInfo ) {
1419                         return null;
1420                 }
1421
1422                 return !$indexInfo[0]->Non_unique;
1423         }
1424
1425         /**
1426          * Helper for Database::insert().
1427          *
1428          * @param array $options
1429          * @return string
1430          */
1431         protected function makeInsertOptions( $options ) {
1432                 return implode( ' ', $options );
1433         }
1434
1435         public function insert( $table, $a, $fname = __METHOD__, $options = [] ) {
1436                 # No rows to insert, easy just return now
1437                 if ( !count( $a ) ) {
1438                         return true;
1439                 }
1440
1441                 $table = $this->tableName( $table );
1442
1443                 if ( !is_array( $options ) ) {
1444                         $options = [ $options ];
1445                 }
1446
1447                 $fh = null;
1448                 if ( isset( $options['fileHandle'] ) ) {
1449                         $fh = $options['fileHandle'];
1450                 }
1451                 $options = $this->makeInsertOptions( $options );
1452
1453                 if ( isset( $a[0] ) && is_array( $a[0] ) ) {
1454                         $multi = true;
1455                         $keys = array_keys( $a[0] );
1456                 } else {
1457                         $multi = false;
1458                         $keys = array_keys( $a );
1459                 }
1460
1461                 $sql = 'INSERT ' . $options .
1462                         " INTO $table (" . implode( ',', $keys ) . ') VALUES ';
1463
1464                 if ( $multi ) {
1465                         $first = true;
1466                         foreach ( $a as $row ) {
1467                                 if ( $first ) {
1468                                         $first = false;
1469                                 } else {
1470                                         $sql .= ',';
1471                                 }
1472                                 $sql .= '(' . $this->makeList( $row ) . ')';
1473                         }
1474                 } else {
1475                         $sql .= '(' . $this->makeList( $a ) . ')';
1476                 }
1477
1478                 if ( $fh !== null && false === fwrite( $fh, $sql ) ) {
1479                         return false;
1480                 } elseif ( $fh !== null ) {
1481                         return true;
1482                 }
1483
1484                 return (bool)$this->query( $sql, $fname );
1485         }
1486
1487         /**
1488          * Make UPDATE options array for Database::makeUpdateOptions
1489          *
1490          * @param array $options
1491          * @return array
1492          */
1493         protected function makeUpdateOptionsArray( $options ) {
1494                 if ( !is_array( $options ) ) {
1495                         $options = [ $options ];
1496                 }
1497
1498                 $opts = [];
1499
1500                 if ( in_array( 'IGNORE', $options ) ) {
1501                         $opts[] = 'IGNORE';
1502                 }
1503
1504                 return $opts;
1505         }
1506
1507         /**
1508          * Make UPDATE options for the Database::update function
1509          *
1510          * @param array $options The options passed to Database::update
1511          * @return string
1512          */
1513         protected function makeUpdateOptions( $options ) {
1514                 $opts = $this->makeUpdateOptionsArray( $options );
1515
1516                 return implode( ' ', $opts );
1517         }
1518
1519         public function update( $table, $values, $conds, $fname = __METHOD__, $options = [] ) {
1520                 $table = $this->tableName( $table );
1521                 $opts = $this->makeUpdateOptions( $options );
1522                 $sql = "UPDATE $opts $table SET " . $this->makeList( $values, self::LIST_SET );
1523
1524                 if ( $conds !== [] && $conds !== '*' ) {
1525                         $sql .= " WHERE " . $this->makeList( $conds, self::LIST_AND );
1526                 }
1527
1528                 return $this->query( $sql, $fname );
1529         }
1530
1531         public function makeList( $a, $mode = self::LIST_COMMA ) {
1532                 if ( !is_array( $a ) ) {
1533                         throw new DBUnexpectedError( $this, __METHOD__ . ' called with incorrect parameters' );
1534                 }
1535
1536                 $first = true;
1537                 $list = '';
1538
1539                 foreach ( $a as $field => $value ) {
1540                         if ( !$first ) {
1541                                 if ( $mode == self::LIST_AND ) {
1542                                         $list .= ' AND ';
1543                                 } elseif ( $mode == self::LIST_OR ) {
1544                                         $list .= ' OR ';
1545                                 } else {
1546                                         $list .= ',';
1547                                 }
1548                         } else {
1549                                 $first = false;
1550                         }
1551
1552                         if ( ( $mode == self::LIST_AND || $mode == self::LIST_OR ) && is_numeric( $field ) ) {
1553                                 $list .= "($value)";
1554                         } elseif ( $mode == self::LIST_SET && is_numeric( $field ) ) {
1555                                 $list .= "$value";
1556                         } elseif (
1557                                 ( $mode == self::LIST_AND || $mode == self::LIST_OR ) && is_array( $value )
1558                         ) {
1559                                 // Remove null from array to be handled separately if found
1560                                 $includeNull = false;
1561                                 foreach ( array_keys( $value, null, true ) as $nullKey ) {
1562                                         $includeNull = true;
1563                                         unset( $value[$nullKey] );
1564                                 }
1565                                 if ( count( $value ) == 0 && !$includeNull ) {
1566                                         throw new InvalidArgumentException(
1567                                                 __METHOD__ . ": empty input for field $field" );
1568                                 } elseif ( count( $value ) == 0 ) {
1569                                         // only check if $field is null
1570                                         $list .= "$field IS NULL";
1571                                 } else {
1572                                         // IN clause contains at least one valid element
1573                                         if ( $includeNull ) {
1574                                                 // Group subconditions to ensure correct precedence
1575                                                 $list .= '(';
1576                                         }
1577                                         if ( count( $value ) == 1 ) {
1578                                                 // Special-case single values, as IN isn't terribly efficient
1579                                                 // Don't necessarily assume the single key is 0; we don't
1580                                                 // enforce linear numeric ordering on other arrays here.
1581                                                 $value = array_values( $value )[0];
1582                                                 $list .= $field . " = " . $this->addQuotes( $value );
1583                                         } else {
1584                                                 $list .= $field . " IN (" . $this->makeList( $value ) . ") ";
1585                                         }
1586                                         // if null present in array, append IS NULL
1587                                         if ( $includeNull ) {
1588                                                 $list .= " OR $field IS NULL)";
1589                                         }
1590                                 }
1591                         } elseif ( $value === null ) {
1592                                 if ( $mode == self::LIST_AND || $mode == self::LIST_OR ) {
1593                                         $list .= "$field IS ";
1594                                 } elseif ( $mode == self::LIST_SET ) {
1595                                         $list .= "$field = ";
1596                                 }
1597                                 $list .= 'NULL';
1598                         } else {
1599                                 if (
1600                                         $mode == self::LIST_AND || $mode == self::LIST_OR || $mode == self::LIST_SET
1601                                 ) {
1602                                         $list .= "$field = ";
1603                                 }
1604                                 $list .= $mode == self::LIST_NAMES ? $value : $this->addQuotes( $value );
1605                         }
1606                 }
1607
1608                 return $list;
1609         }
1610
1611         public function makeWhereFrom2d( $data, $baseKey, $subKey ) {
1612                 $conds = [];
1613
1614                 foreach ( $data as $base => $sub ) {
1615                         if ( count( $sub ) ) {
1616                                 $conds[] = $this->makeList(
1617                                         [ $baseKey => $base, $subKey => array_keys( $sub ) ],
1618                                         self::LIST_AND );
1619                         }
1620                 }
1621
1622                 if ( $conds ) {
1623                         return $this->makeList( $conds, self::LIST_OR );
1624                 } else {
1625                         // Nothing to search for...
1626                         return false;
1627                 }
1628         }
1629
1630         public function aggregateValue( $valuedata, $valuename = 'value' ) {
1631                 return $valuename;
1632         }
1633
1634         public function bitNot( $field ) {
1635                 return "(~$field)";
1636         }
1637
1638         public function bitAnd( $fieldLeft, $fieldRight ) {
1639                 return "($fieldLeft & $fieldRight)";
1640         }
1641
1642         public function bitOr( $fieldLeft, $fieldRight ) {
1643                 return "($fieldLeft | $fieldRight)";
1644         }
1645
1646         public function buildConcat( $stringList ) {
1647                 return 'CONCAT(' . implode( ',', $stringList ) . ')';
1648         }
1649
1650         public function buildGroupConcatField(
1651                 $delim, $table, $field, $conds = '', $join_conds = []
1652         ) {
1653                 $fld = "GROUP_CONCAT($field SEPARATOR " . $this->addQuotes( $delim ) . ')';
1654
1655                 return '(' . $this->selectSQLText( $table, $fld, $conds, null, [], $join_conds ) . ')';
1656         }
1657
1658         public function buildStringCast( $field ) {
1659                 return $field;
1660         }
1661
1662         public function selectDB( $db ) {
1663                 # Stub. Shouldn't cause serious problems if it's not overridden, but
1664                 # if your database engine supports a concept similar to MySQL's
1665                 # databases you may as well.
1666                 $this->mDBname = $db;
1667
1668                 return true;
1669         }
1670
1671         public function getDBname() {
1672                 return $this->mDBname;
1673         }
1674
1675         public function getServer() {
1676                 return $this->mServer;
1677         }
1678
1679         public function tableName( $name, $format = 'quoted' ) {
1680                 # Skip the entire process when we have a string quoted on both ends.
1681                 # Note that we check the end so that we will still quote any use of
1682                 # use of `database`.table. But won't break things if someone wants
1683                 # to query a database table with a dot in the name.
1684                 if ( $this->isQuotedIdentifier( $name ) ) {
1685                         return $name;
1686                 }
1687
1688                 # Lets test for any bits of text that should never show up in a table
1689                 # name. Basically anything like JOIN or ON which are actually part of
1690                 # SQL queries, but may end up inside of the table value to combine
1691                 # sql. Such as how the API is doing.
1692                 # Note that we use a whitespace test rather than a \b test to avoid
1693                 # any remote case where a word like on may be inside of a table name
1694                 # surrounded by symbols which may be considered word breaks.
1695                 if ( preg_match( '/(^|\s)(DISTINCT|JOIN|ON|AS)(\s|$)/i', $name ) !== 0 ) {
1696                         return $name;
1697                 }
1698
1699                 # Split database and table into proper variables.
1700                 # We reverse the explode so that database.table and table both output
1701                 # the correct table.
1702                 $dbDetails = explode( '.', $name, 3 );
1703                 if ( count( $dbDetails ) == 3 ) {
1704                         list( $database, $schema, $table ) = $dbDetails;
1705                         # We don't want any prefix added in this case
1706                         $prefix = '';
1707                 } elseif ( count( $dbDetails ) == 2 ) {
1708                         list( $database, $table ) = $dbDetails;
1709                         # We don't want any prefix added in this case
1710                         # In dbs that support it, $database may actually be the schema
1711                         # but that doesn't affect any of the functionality here
1712                         $prefix = '';
1713                         $schema = '';
1714                 } else {
1715                         list( $table ) = $dbDetails;
1716                         if ( isset( $this->tableAliases[$table] ) ) {
1717                                 $database = $this->tableAliases[$table]['dbname'];
1718                                 $schema = is_string( $this->tableAliases[$table]['schema'] )
1719                                         ? $this->tableAliases[$table]['schema']
1720                                         : $this->mSchema;
1721                                 $prefix = is_string( $this->tableAliases[$table]['prefix'] )
1722                                         ? $this->tableAliases[$table]['prefix']
1723                                         : $this->mTablePrefix;
1724                         } else {
1725                                 $database = '';
1726                                 $schema = $this->mSchema; # Default schema
1727                                 $prefix = $this->mTablePrefix; # Default prefix
1728                         }
1729                 }
1730
1731                 # Quote $table and apply the prefix if not quoted.
1732                 # $tableName might be empty if this is called from Database::replaceVars()
1733                 $tableName = "{$prefix}{$table}";
1734                 if ( $format == 'quoted'
1735                         && !$this->isQuotedIdentifier( $tableName ) && $tableName !== ''
1736                 ) {
1737                         $tableName = $this->addIdentifierQuotes( $tableName );
1738                 }
1739
1740                 # Quote $schema and merge it with the table name if needed
1741                 if ( strlen( $schema ) ) {
1742                         if ( $format == 'quoted' && !$this->isQuotedIdentifier( $schema ) ) {
1743                                 $schema = $this->addIdentifierQuotes( $schema );
1744                         }
1745                         $tableName = $schema . '.' . $tableName;
1746                 }
1747
1748                 # Quote $database and merge it with the table name if needed
1749                 if ( $database !== '' ) {
1750                         if ( $format == 'quoted' && !$this->isQuotedIdentifier( $database ) ) {
1751                                 $database = $this->addIdentifierQuotes( $database );
1752                         }
1753                         $tableName = $database . '.' . $tableName;
1754                 }
1755
1756                 return $tableName;
1757         }
1758
1759         public function tableNames() {
1760                 $inArray = func_get_args();
1761                 $retVal = [];
1762
1763                 foreach ( $inArray as $name ) {
1764                         $retVal[$name] = $this->tableName( $name );
1765                 }
1766
1767                 return $retVal;
1768         }
1769
1770         public function tableNamesN() {
1771                 $inArray = func_get_args();
1772                 $retVal = [];
1773
1774                 foreach ( $inArray as $name ) {
1775                         $retVal[] = $this->tableName( $name );
1776                 }
1777
1778                 return $retVal;
1779         }
1780
1781         /**
1782          * Get an aliased table name
1783          * e.g. tableName AS newTableName
1784          *
1785          * @param string $name Table name, see tableName()
1786          * @param string|bool $alias Alias (optional)
1787          * @return string SQL name for aliased table. Will not alias a table to its own name
1788          */
1789         protected function tableNameWithAlias( $name, $alias = false ) {
1790                 if ( !$alias || $alias == $name ) {
1791                         return $this->tableName( $name );
1792                 } else {
1793                         return $this->tableName( $name ) . ' ' . $this->addIdentifierQuotes( $alias );
1794                 }
1795         }
1796
1797         /**
1798          * Gets an array of aliased table names
1799          *
1800          * @param array $tables [ [alias] => table ]
1801          * @return string[] See tableNameWithAlias()
1802          */
1803         protected function tableNamesWithAlias( $tables ) {
1804                 $retval = [];
1805                 foreach ( $tables as $alias => $table ) {
1806                         if ( is_numeric( $alias ) ) {
1807                                 $alias = $table;
1808                         }
1809                         $retval[] = $this->tableNameWithAlias( $table, $alias );
1810                 }
1811
1812                 return $retval;
1813         }
1814
1815         /**
1816          * Get an aliased field name
1817          * e.g. fieldName AS newFieldName
1818          *
1819          * @param string $name Field name
1820          * @param string|bool $alias Alias (optional)
1821          * @return string SQL name for aliased field. Will not alias a field to its own name
1822          */
1823         protected function fieldNameWithAlias( $name, $alias = false ) {
1824                 if ( !$alias || (string)$alias === (string)$name ) {
1825                         return $name;
1826                 } else {
1827                         return $name . ' AS ' . $this->addIdentifierQuotes( $alias ); // PostgreSQL needs AS
1828                 }
1829         }
1830
1831         /**
1832          * Gets an array of aliased field names
1833          *
1834          * @param array $fields [ [alias] => field ]
1835          * @return string[] See fieldNameWithAlias()
1836          */
1837         protected function fieldNamesWithAlias( $fields ) {
1838                 $retval = [];
1839                 foreach ( $fields as $alias => $field ) {
1840                         if ( is_numeric( $alias ) ) {
1841                                 $alias = $field;
1842                         }
1843                         $retval[] = $this->fieldNameWithAlias( $field, $alias );
1844                 }
1845
1846                 return $retval;
1847         }
1848
1849         /**
1850          * Get the aliased table name clause for a FROM clause
1851          * which might have a JOIN and/or USE INDEX or IGNORE INDEX clause
1852          *
1853          * @param array $tables ( [alias] => table )
1854          * @param array $use_index Same as for select()
1855          * @param array $ignore_index Same as for select()
1856          * @param array $join_conds Same as for select()
1857          * @return string
1858          */
1859         protected function tableNamesWithIndexClauseOrJOIN(
1860                 $tables, $use_index = [], $ignore_index = [], $join_conds = []
1861         ) {
1862                 $ret = [];
1863                 $retJOIN = [];
1864                 $use_index = (array)$use_index;
1865                 $ignore_index = (array)$ignore_index;
1866                 $join_conds = (array)$join_conds;
1867
1868                 foreach ( $tables as $alias => $table ) {
1869                         if ( !is_string( $alias ) ) {
1870                                 // No alias? Set it equal to the table name
1871                                 $alias = $table;
1872                         }
1873                         // Is there a JOIN clause for this table?
1874                         if ( isset( $join_conds[$alias] ) ) {
1875                                 list( $joinType, $conds ) = $join_conds[$alias];
1876                                 $tableClause = $joinType;
1877                                 $tableClause .= ' ' . $this->tableNameWithAlias( $table, $alias );
1878                                 if ( isset( $use_index[$alias] ) ) { // has USE INDEX?
1879                                         $use = $this->useIndexClause( implode( ',', (array)$use_index[$alias] ) );
1880                                         if ( $use != '' ) {
1881                                                 $tableClause .= ' ' . $use;
1882                                         }
1883                                 }
1884                                 if ( isset( $ignore_index[$alias] ) ) { // has IGNORE INDEX?
1885                                         $ignore = $this->ignoreIndexClause(
1886                                                 implode( ',', (array)$ignore_index[$alias] ) );
1887                                         if ( $ignore != '' ) {
1888                                                 $tableClause .= ' ' . $ignore;
1889                                         }
1890                                 }
1891                                 $on = $this->makeList( (array)$conds, self::LIST_AND );
1892                                 if ( $on != '' ) {
1893                                         $tableClause .= ' ON (' . $on . ')';
1894                                 }
1895
1896                                 $retJOIN[] = $tableClause;
1897                         } elseif ( isset( $use_index[$alias] ) ) {
1898                                 // Is there an INDEX clause for this table?
1899                                 $tableClause = $this->tableNameWithAlias( $table, $alias );
1900                                 $tableClause .= ' ' . $this->useIndexClause(
1901                                                 implode( ',', (array)$use_index[$alias] )
1902                                         );
1903
1904                                 $ret[] = $tableClause;
1905                         } elseif ( isset( $ignore_index[$alias] ) ) {
1906                                 // Is there an INDEX clause for this table?
1907                                 $tableClause = $this->tableNameWithAlias( $table, $alias );
1908                                 $tableClause .= ' ' . $this->ignoreIndexClause(
1909                                                 implode( ',', (array)$ignore_index[$alias] )
1910                                         );
1911
1912                                 $ret[] = $tableClause;
1913                         } else {
1914                                 $tableClause = $this->tableNameWithAlias( $table, $alias );
1915
1916                                 $ret[] = $tableClause;
1917                         }
1918                 }
1919
1920                 // We can't separate explicit JOIN clauses with ',', use ' ' for those
1921                 $implicitJoins = !empty( $ret ) ? implode( ',', $ret ) : "";
1922                 $explicitJoins = !empty( $retJOIN ) ? implode( ' ', $retJOIN ) : "";
1923
1924                 // Compile our final table clause
1925                 return implode( ' ', [ $implicitJoins, $explicitJoins ] );
1926         }
1927
1928         /**
1929          * Get the name of an index in a given table.
1930          *
1931          * @param string $index
1932          * @return string
1933          */
1934         protected function indexName( $index ) {
1935                 return $index;
1936         }
1937
1938         public function addQuotes( $s ) {
1939                 if ( $s instanceof Blob ) {
1940                         $s = $s->fetch();
1941                 }
1942                 if ( $s === null ) {
1943                         return 'NULL';
1944                 } elseif ( is_bool( $s ) ) {
1945                         return (int)$s;
1946                 } else {
1947                         # This will also quote numeric values. This should be harmless,
1948                         # and protects against weird problems that occur when they really
1949                         # _are_ strings such as article titles and string->number->string
1950                         # conversion is not 1:1.
1951                         return "'" . $this->strencode( $s ) . "'";
1952                 }
1953         }
1954
1955         /**
1956          * Quotes an identifier using `backticks` or "double quotes" depending on the database type.
1957          * MySQL uses `backticks` while basically everything else uses double quotes.
1958          * Since MySQL is the odd one out here the double quotes are our generic
1959          * and we implement backticks in DatabaseMysql.
1960          *
1961          * @param string $s
1962          * @return string
1963          */
1964         public function addIdentifierQuotes( $s ) {
1965                 return '"' . str_replace( '"', '""', $s ) . '"';
1966         }
1967
1968         /**
1969          * Returns if the given identifier looks quoted or not according to
1970          * the database convention for quoting identifiers .
1971          *
1972          * @note Do not use this to determine if untrusted input is safe.
1973          *   A malicious user can trick this function.
1974          * @param string $name
1975          * @return bool
1976          */
1977         public function isQuotedIdentifier( $name ) {
1978                 return $name[0] == '"' && substr( $name, -1, 1 ) == '"';
1979         }
1980
1981         /**
1982          * @param string $s
1983          * @return string
1984          */
1985         protected function escapeLikeInternal( $s ) {
1986                 return addcslashes( $s, '\%_' );
1987         }
1988
1989         public function buildLike() {
1990                 $params = func_get_args();
1991
1992                 if ( count( $params ) > 0 && is_array( $params[0] ) ) {
1993                         $params = $params[0];
1994                 }
1995
1996                 $s = '';
1997
1998                 foreach ( $params as $value ) {
1999                         if ( $value instanceof LikeMatch ) {
2000                                 $s .= $value->toString();
2001                         } else {
2002                                 $s .= $this->escapeLikeInternal( $value );
2003                         }
2004                 }
2005
2006                 return " LIKE {$this->addQuotes( $s )} ";
2007         }
2008
2009         public function anyChar() {
2010                 return new LikeMatch( '_' );
2011         }
2012
2013         public function anyString() {
2014                 return new LikeMatch( '%' );
2015         }
2016
2017         public function nextSequenceValue( $seqName ) {
2018                 return null;
2019         }
2020
2021         /**
2022          * USE INDEX clause. Unlikely to be useful for anything but MySQL. This
2023          * is only needed because a) MySQL must be as efficient as possible due to
2024          * its use on Wikipedia, and b) MySQL 4.0 is kind of dumb sometimes about
2025          * which index to pick. Anyway, other databases might have different
2026          * indexes on a given table. So don't bother overriding this unless you're
2027          * MySQL.
2028          * @param string $index
2029          * @return string
2030          */
2031         public function useIndexClause( $index ) {
2032                 return '';
2033         }
2034
2035         /**
2036          * IGNORE INDEX clause. Unlikely to be useful for anything but MySQL. This
2037          * is only needed because a) MySQL must be as efficient as possible due to
2038          * its use on Wikipedia, and b) MySQL 4.0 is kind of dumb sometimes about
2039          * which index to pick. Anyway, other databases might have different
2040          * indexes on a given table. So don't bother overriding this unless you're
2041          * MySQL.
2042          * @param string $index
2043          * @return string
2044          */
2045         public function ignoreIndexClause( $index ) {
2046                 return '';
2047         }
2048
2049         public function replace( $table, $uniqueIndexes, $rows, $fname = __METHOD__ ) {
2050                 $quotedTable = $this->tableName( $table );
2051
2052                 if ( count( $rows ) == 0 ) {
2053                         return;
2054                 }
2055
2056                 # Single row case
2057                 if ( !is_array( reset( $rows ) ) ) {
2058                         $rows = [ $rows ];
2059                 }
2060
2061                 // @FXIME: this is not atomic, but a trx would break affectedRows()
2062                 foreach ( $rows as $row ) {
2063                         # Delete rows which collide
2064                         if ( $uniqueIndexes ) {
2065                                 $sql = "DELETE FROM $quotedTable WHERE ";
2066                                 $first = true;
2067                                 foreach ( $uniqueIndexes as $index ) {
2068                                         if ( $first ) {
2069                                                 $first = false;
2070                                                 $sql .= '( ';
2071                                         } else {
2072                                                 $sql .= ' ) OR ( ';
2073                                         }
2074                                         if ( is_array( $index ) ) {
2075                                                 $first2 = true;
2076                                                 foreach ( $index as $col ) {
2077                                                         if ( $first2 ) {
2078                                                                 $first2 = false;
2079                                                         } else {
2080                                                                 $sql .= ' AND ';
2081                                                         }
2082                                                         $sql .= $col . '=' . $this->addQuotes( $row[$col] );
2083                                                 }
2084                                         } else {
2085                                                 $sql .= $index . '=' . $this->addQuotes( $row[$index] );
2086                                         }
2087                                 }
2088                                 $sql .= ' )';
2089                                 $this->query( $sql, $fname );
2090                         }
2091
2092                         # Now insert the row
2093                         $this->insert( $table, $row, $fname );
2094                 }
2095         }
2096
2097         /**
2098          * REPLACE query wrapper for MySQL and SQLite, which have a native REPLACE
2099          * statement.
2100          *
2101          * @param string $table Table name
2102          * @param array|string $rows Row(s) to insert
2103          * @param string $fname Caller function name
2104          *
2105          * @return ResultWrapper
2106          */
2107         protected function nativeReplace( $table, $rows, $fname ) {
2108                 $table = $this->tableName( $table );
2109
2110                 # Single row case
2111                 if ( !is_array( reset( $rows ) ) ) {
2112                         $rows = [ $rows ];
2113                 }
2114
2115                 $sql = "REPLACE INTO $table (" . implode( ',', array_keys( $rows[0] ) ) . ') VALUES ';
2116                 $first = true;
2117
2118                 foreach ( $rows as $row ) {
2119                         if ( $first ) {
2120                                 $first = false;
2121                         } else {
2122                                 $sql .= ',';
2123                         }
2124
2125                         $sql .= '(' . $this->makeList( $row ) . ')';
2126                 }
2127
2128                 return $this->query( $sql, $fname );
2129         }
2130
2131         public function upsert( $table, array $rows, array $uniqueIndexes, array $set,
2132                 $fname = __METHOD__
2133         ) {
2134                 if ( !count( $rows ) ) {
2135                         return true; // nothing to do
2136                 }
2137
2138                 if ( !is_array( reset( $rows ) ) ) {
2139                         $rows = [ $rows ];
2140                 }
2141
2142                 if ( count( $uniqueIndexes ) ) {
2143                         $clauses = []; // list WHERE clauses that each identify a single row
2144                         foreach ( $rows as $row ) {
2145                                 foreach ( $uniqueIndexes as $index ) {
2146                                         $index = is_array( $index ) ? $index : [ $index ]; // columns
2147                                         $rowKey = []; // unique key to this row
2148                                         foreach ( $index as $column ) {
2149                                                 $rowKey[$column] = $row[$column];
2150                                         }
2151                                         $clauses[] = $this->makeList( $rowKey, self::LIST_AND );
2152                                 }
2153                         }
2154                         $where = [ $this->makeList( $clauses, self::LIST_OR ) ];
2155                 } else {
2156                         $where = false;
2157                 }
2158
2159                 $useTrx = !$this->mTrxLevel;
2160                 if ( $useTrx ) {
2161                         $this->begin( $fname, self::TRANSACTION_INTERNAL );
2162                 }
2163                 try {
2164                         # Update any existing conflicting row(s)
2165                         if ( $where !== false ) {
2166                                 $ok = $this->update( $table, $set, $where, $fname );
2167                         } else {
2168                                 $ok = true;
2169                         }
2170                         # Now insert any non-conflicting row(s)
2171                         $ok = $this->insert( $table, $rows, $fname, [ 'IGNORE' ] ) && $ok;
2172                 } catch ( Exception $e ) {
2173                         if ( $useTrx ) {
2174                                 $this->rollback( $fname, self::FLUSHING_INTERNAL );
2175                         }
2176                         throw $e;
2177                 }
2178                 if ( $useTrx ) {
2179                         $this->commit( $fname, self::FLUSHING_INTERNAL );
2180                 }
2181
2182                 return $ok;
2183         }
2184
2185         public function deleteJoin( $delTable, $joinTable, $delVar, $joinVar, $conds,
2186                 $fname = __METHOD__
2187         ) {
2188                 if ( !$conds ) {
2189                         throw new DBUnexpectedError( $this, __METHOD__ . ' called with empty $conds' );
2190                 }
2191
2192                 $delTable = $this->tableName( $delTable );
2193                 $joinTable = $this->tableName( $joinTable );
2194                 $sql = "DELETE FROM $delTable WHERE $delVar IN (SELECT $joinVar FROM $joinTable ";
2195                 if ( $conds != '*' ) {
2196                         $sql .= 'WHERE ' . $this->makeList( $conds, self::LIST_AND );
2197                 }
2198                 $sql .= ')';
2199
2200                 $this->query( $sql, $fname );
2201         }
2202
2203         public function textFieldSize( $table, $field ) {
2204                 $table = $this->tableName( $table );
2205                 $sql = "SHOW COLUMNS FROM $table LIKE \"$field\";";
2206                 $res = $this->query( $sql, __METHOD__ );
2207                 $row = $this->fetchObject( $res );
2208
2209                 $m = [];
2210
2211                 if ( preg_match( '/\((.*)\)/', $row->Type, $m ) ) {
2212                         $size = $m[1];
2213                 } else {
2214                         $size = -1;
2215                 }
2216
2217                 return $size;
2218         }
2219
2220         public function delete( $table, $conds, $fname = __METHOD__ ) {
2221                 if ( !$conds ) {
2222                         throw new DBUnexpectedError( $this, __METHOD__ . ' called with no conditions' );
2223                 }
2224
2225                 $table = $this->tableName( $table );
2226                 $sql = "DELETE FROM $table";
2227
2228                 if ( $conds != '*' ) {
2229                         if ( is_array( $conds ) ) {
2230                                 $conds = $this->makeList( $conds, self::LIST_AND );
2231                         }
2232                         $sql .= ' WHERE ' . $conds;
2233                 }
2234
2235                 return $this->query( $sql, $fname );
2236         }
2237
2238         public function insertSelect(
2239                 $destTable, $srcTable, $varMap, $conds,
2240                 $fname = __METHOD__, $insertOptions = [], $selectOptions = []
2241         ) {
2242                 if ( $this->cliMode ) {
2243                         // For massive migrations with downtime, we don't want to select everything
2244                         // into memory and OOM, so do all this native on the server side if possible.
2245                         return $this->nativeInsertSelect(
2246                                 $destTable,
2247                                 $srcTable,
2248                                 $varMap,
2249                                 $conds,
2250                                 $fname,
2251                                 $insertOptions,
2252                                 $selectOptions
2253                         );
2254                 }
2255
2256                 // For web requests, do a locking SELECT and then INSERT. This puts the SELECT burden
2257                 // on only the master (without needing row-based-replication). It also makes it easy to
2258                 // know how big the INSERT is going to be.
2259                 $fields = [];
2260                 foreach ( $varMap as $dstColumn => $sourceColumnOrSql ) {
2261                         $fields[] = $this->fieldNameWithAlias( $sourceColumnOrSql, $dstColumn );
2262                 }
2263                 $selectOptions[] = 'FOR UPDATE';
2264                 $res = $this->select( $srcTable, implode( ',', $fields ), $conds, $fname, $selectOptions );
2265                 if ( !$res ) {
2266                         return false;
2267                 }
2268
2269                 $rows = [];
2270                 foreach ( $res as $row ) {
2271                         $rows[] = (array)$row;
2272                 }
2273
2274                 return $this->insert( $destTable, $rows, $fname, $insertOptions );
2275         }
2276
2277         protected function nativeInsertSelect( $destTable, $srcTable, $varMap, $conds,
2278                 $fname = __METHOD__,
2279                 $insertOptions = [], $selectOptions = []
2280         ) {
2281                 $destTable = $this->tableName( $destTable );
2282
2283                 if ( !is_array( $insertOptions ) ) {
2284                         $insertOptions = [ $insertOptions ];
2285                 }
2286
2287                 $insertOptions = $this->makeInsertOptions( $insertOptions );
2288
2289                 if ( !is_array( $selectOptions ) ) {
2290                         $selectOptions = [ $selectOptions ];
2291                 }
2292
2293                 list( $startOpts, $useIndex, $tailOpts, $ignoreIndex ) = $this->makeSelectOptions(
2294                         $selectOptions );
2295
2296                 if ( is_array( $srcTable ) ) {
2297                         $srcTable = implode( ',', array_map( [ &$this, 'tableName' ], $srcTable ) );
2298                 } else {
2299                         $srcTable = $this->tableName( $srcTable );
2300                 }
2301
2302                 $sql = "INSERT $insertOptions" .
2303                         " INTO $destTable (" . implode( ',', array_keys( $varMap ) ) . ')' .
2304                         " SELECT $startOpts " . implode( ',', $varMap ) .
2305                         " FROM $srcTable $useIndex $ignoreIndex ";
2306
2307                 if ( $conds != '*' ) {
2308                         if ( is_array( $conds ) ) {
2309                                 $conds = $this->makeList( $conds, self::LIST_AND );
2310                         }
2311                         $sql .= " WHERE $conds";
2312                 }
2313
2314                 $sql .= " $tailOpts";
2315
2316                 return $this->query( $sql, $fname );
2317         }
2318
2319         /**
2320          * Construct a LIMIT query with optional offset. This is used for query
2321          * pages. The SQL should be adjusted so that only the first $limit rows
2322          * are returned. If $offset is provided as well, then the first $offset
2323          * rows should be discarded, and the next $limit rows should be returned.
2324          * If the result of the query is not ordered, then the rows to be returned
2325          * are theoretically arbitrary.
2326          *
2327          * $sql is expected to be a SELECT, if that makes a difference.
2328          *
2329          * The version provided by default works in MySQL and SQLite. It will very
2330          * likely need to be overridden for most other DBMSes.
2331          *
2332          * @param string $sql SQL query we will append the limit too
2333          * @param int $limit The SQL limit
2334          * @param int|bool $offset The SQL offset (default false)
2335          * @throws DBUnexpectedError
2336          * @return string
2337          */
2338         public function limitResult( $sql, $limit, $offset = false ) {
2339                 if ( !is_numeric( $limit ) ) {
2340                         throw new DBUnexpectedError( $this,
2341                                 "Invalid non-numeric limit passed to limitResult()\n" );
2342                 }
2343
2344                 return "$sql LIMIT "
2345                 . ( ( is_numeric( $offset ) && $offset != 0 ) ? "{$offset}," : "" )
2346                 . "{$limit} ";
2347         }
2348
2349         public function unionSupportsOrderAndLimit() {
2350                 return true; // True for almost every DB supported
2351         }
2352
2353         public function unionQueries( $sqls, $all ) {
2354                 $glue = $all ? ') UNION ALL (' : ') UNION (';
2355
2356                 return '(' . implode( $glue, $sqls ) . ')';
2357         }
2358
2359         public function conditional( $cond, $trueVal, $falseVal ) {
2360                 if ( is_array( $cond ) ) {
2361                         $cond = $this->makeList( $cond, self::LIST_AND );
2362                 }
2363
2364                 return " (CASE WHEN $cond THEN $trueVal ELSE $falseVal END) ";
2365         }
2366
2367         public function strreplace( $orig, $old, $new ) {
2368                 return "REPLACE({$orig}, {$old}, {$new})";
2369         }
2370
2371         public function getServerUptime() {
2372                 return 0;
2373         }
2374
2375         public function wasDeadlock() {
2376                 return false;
2377         }
2378
2379         public function wasLockTimeout() {
2380                 return false;
2381         }
2382
2383         public function wasErrorReissuable() {
2384                 return false;
2385         }
2386
2387         public function wasReadOnlyError() {
2388                 return false;
2389         }
2390
2391         /**
2392          * Do not use this method outside of Database/DBError classes
2393          *
2394          * @param integer|string $errno
2395          * @return bool Whether the given query error was a connection drop
2396          */
2397         public function wasConnectionError( $errno ) {
2398                 return false;
2399         }
2400
2401         public function deadlockLoop() {
2402                 $args = func_get_args();
2403                 $function = array_shift( $args );
2404                 $tries = self::DEADLOCK_TRIES;
2405
2406                 $this->begin( __METHOD__ );
2407
2408                 $retVal = null;
2409                 /** @var Exception $e */
2410                 $e = null;
2411                 do {
2412                         try {
2413                                 $retVal = call_user_func_array( $function, $args );
2414                                 break;
2415                         } catch ( DBQueryError $e ) {
2416                                 if ( $this->wasDeadlock() ) {
2417                                         // Retry after a randomized delay
2418                                         usleep( mt_rand( self::DEADLOCK_DELAY_MIN, self::DEADLOCK_DELAY_MAX ) );
2419                                 } else {
2420                                         // Throw the error back up
2421                                         throw $e;
2422                                 }
2423                         }
2424                 } while ( --$tries > 0 );
2425
2426                 if ( $tries <= 0 ) {
2427                         // Too many deadlocks; give up
2428                         $this->rollback( __METHOD__ );
2429                         throw $e;
2430                 } else {
2431                         $this->commit( __METHOD__ );
2432
2433                         return $retVal;
2434                 }
2435         }
2436
2437         public function masterPosWait( DBMasterPos $pos, $timeout ) {
2438                 # Real waits are implemented in the subclass.
2439                 return 0;
2440         }
2441
2442         public function getReplicaPos() {
2443                 # Stub
2444                 return false;
2445         }
2446
2447         public function getMasterPos() {
2448                 # Stub
2449                 return false;
2450         }
2451
2452         public function serverIsReadOnly() {
2453                 return false;
2454         }
2455
2456         final public function onTransactionResolution( callable $callback, $fname = __METHOD__ ) {
2457                 if ( !$this->mTrxLevel ) {
2458                         throw new DBUnexpectedError( $this, "No transaction is active." );
2459                 }
2460                 $this->mTrxEndCallbacks[] = [ $callback, $fname ];
2461         }
2462
2463         final public function onTransactionIdle( callable $callback, $fname = __METHOD__ ) {
2464                 $this->mTrxIdleCallbacks[] = [ $callback, $fname ];
2465                 if ( !$this->mTrxLevel ) {
2466                         $this->runOnTransactionIdleCallbacks( self::TRIGGER_IDLE );
2467                 }
2468         }
2469
2470         final public function onTransactionPreCommitOrIdle( callable $callback, $fname = __METHOD__ ) {
2471                 if ( $this->mTrxLevel ) {
2472                         $this->mTrxPreCommitCallbacks[] = [ $callback, $fname ];
2473                 } else {
2474                         // If no transaction is active, then make one for this callback
2475                         $this->startAtomic( __METHOD__ );
2476                         try {
2477                                 call_user_func( $callback );
2478                                 $this->endAtomic( __METHOD__ );
2479                         } catch ( Exception $e ) {
2480                                 $this->rollback( __METHOD__, self::FLUSHING_INTERNAL );
2481                                 throw $e;
2482                         }
2483                 }
2484         }
2485
2486         final public function setTransactionListener( $name, callable $callback = null ) {
2487                 if ( $callback ) {
2488                         $this->mTrxRecurringCallbacks[$name] = $callback;
2489                 } else {
2490                         unset( $this->mTrxRecurringCallbacks[$name] );
2491                 }
2492         }
2493
2494         /**
2495          * Whether to disable running of post-COMMIT/ROLLBACK callbacks
2496          *
2497          * This method should not be used outside of Database/LoadBalancer
2498          *
2499          * @param bool $suppress
2500          * @since 1.28
2501          */
2502         final public function setTrxEndCallbackSuppression( $suppress ) {
2503                 $this->mTrxEndCallbacksSuppressed = $suppress;
2504         }
2505
2506         /**
2507          * Actually run and consume any "on transaction idle/resolution" callbacks.
2508          *
2509          * This method should not be used outside of Database/LoadBalancer
2510          *
2511          * @param integer $trigger IDatabase::TRIGGER_* constant
2512          * @since 1.20
2513          * @throws Exception
2514          */
2515         public function runOnTransactionIdleCallbacks( $trigger ) {
2516                 if ( $this->mTrxEndCallbacksSuppressed ) {
2517                         return;
2518                 }
2519
2520                 $autoTrx = $this->getFlag( self::DBO_TRX ); // automatic begin() enabled?
2521                 /** @var Exception $e */
2522                 $e = null; // first exception
2523                 do { // callbacks may add callbacks :)
2524                         $callbacks = array_merge(
2525                                 $this->mTrxIdleCallbacks,
2526                                 $this->mTrxEndCallbacks // include "transaction resolution" callbacks
2527                         );
2528                         $this->mTrxIdleCallbacks = []; // consumed (and recursion guard)
2529                         $this->mTrxEndCallbacks = []; // consumed (recursion guard)
2530                         foreach ( $callbacks as $callback ) {
2531                                 try {
2532                                         list( $phpCallback ) = $callback;
2533                                         $this->clearFlag( self::DBO_TRX ); // make each query its own transaction
2534                                         call_user_func_array( $phpCallback, [ $trigger ] );
2535                                         if ( $autoTrx ) {
2536                                                 $this->setFlag( self::DBO_TRX ); // restore automatic begin()
2537                                         } else {
2538                                                 $this->clearFlag( self::DBO_TRX ); // restore auto-commit
2539                                         }
2540                                 } catch ( Exception $ex ) {
2541                                         call_user_func( $this->errorLogger, $ex );
2542                                         $e = $e ?: $ex;
2543                                         // Some callbacks may use startAtomic/endAtomic, so make sure
2544                                         // their transactions are ended so other callbacks don't fail
2545                                         if ( $this->trxLevel() ) {
2546                                                 $this->rollback( __METHOD__, self::FLUSHING_INTERNAL );
2547                                         }
2548                                 }
2549                         }
2550                 } while ( count( $this->mTrxIdleCallbacks ) );
2551
2552                 if ( $e instanceof Exception ) {
2553                         throw $e; // re-throw any first exception
2554                 }
2555         }
2556
2557         /**
2558          * Actually run and consume any "on transaction pre-commit" callbacks.
2559          *
2560          * This method should not be used outside of Database/LoadBalancer
2561          *
2562          * @since 1.22
2563          * @throws Exception
2564          */
2565         public function runOnTransactionPreCommitCallbacks() {
2566                 $e = null; // first exception
2567                 do { // callbacks may add callbacks :)
2568                         $callbacks = $this->mTrxPreCommitCallbacks;
2569                         $this->mTrxPreCommitCallbacks = []; // consumed (and recursion guard)
2570                         foreach ( $callbacks as $callback ) {
2571                                 try {
2572                                         list( $phpCallback ) = $callback;
2573                                         call_user_func( $phpCallback );
2574                                 } catch ( Exception $ex ) {
2575                                         call_user_func( $this->errorLogger, $ex );
2576                                         $e = $e ?: $ex;
2577                                 }
2578                         }
2579                 } while ( count( $this->mTrxPreCommitCallbacks ) );
2580
2581                 if ( $e instanceof Exception ) {
2582                         throw $e; // re-throw any first exception
2583                 }
2584         }
2585
2586         /**
2587          * Actually run any "transaction listener" callbacks.
2588          *
2589          * This method should not be used outside of Database/LoadBalancer
2590          *
2591          * @param integer $trigger IDatabase::TRIGGER_* constant
2592          * @throws Exception
2593          * @since 1.20
2594          */
2595         public function runTransactionListenerCallbacks( $trigger ) {
2596                 if ( $this->mTrxEndCallbacksSuppressed ) {
2597                         return;
2598                 }
2599
2600                 /** @var Exception $e */
2601                 $e = null; // first exception
2602
2603                 foreach ( $this->mTrxRecurringCallbacks as $phpCallback ) {
2604                         try {
2605                                 $phpCallback( $trigger, $this );
2606                         } catch ( Exception $ex ) {
2607                                 call_user_func( $this->errorLogger, $ex );
2608                                 $e = $e ?: $ex;
2609                         }
2610                 }
2611
2612                 if ( $e instanceof Exception ) {
2613                         throw $e; // re-throw any first exception
2614                 }
2615         }
2616
2617         final public function startAtomic( $fname = __METHOD__ ) {
2618                 if ( !$this->mTrxLevel ) {
2619                         $this->begin( $fname, self::TRANSACTION_INTERNAL );
2620                         // If DBO_TRX is set, a series of startAtomic/endAtomic pairs will result
2621                         // in all changes being in one transaction to keep requests transactional.
2622                         if ( !$this->getFlag( self::DBO_TRX ) ) {
2623                                 $this->mTrxAutomaticAtomic = true;
2624                         }
2625                 }
2626
2627                 $this->mTrxAtomicLevels[] = $fname;
2628         }
2629
2630         final public function endAtomic( $fname = __METHOD__ ) {
2631                 if ( !$this->mTrxLevel ) {
2632                         throw new DBUnexpectedError( $this, "No atomic transaction is open (got $fname)." );
2633                 }
2634                 if ( !$this->mTrxAtomicLevels ||
2635                         array_pop( $this->mTrxAtomicLevels ) !== $fname
2636                 ) {
2637                         throw new DBUnexpectedError( $this, "Invalid atomic section ended (got $fname)." );
2638                 }
2639
2640                 if ( !$this->mTrxAtomicLevels && $this->mTrxAutomaticAtomic ) {
2641                         $this->commit( $fname, self::FLUSHING_INTERNAL );
2642                 }
2643         }
2644
2645         final public function doAtomicSection( $fname, callable $callback ) {
2646                 $this->startAtomic( $fname );
2647                 try {
2648                         $res = call_user_func_array( $callback, [ $this, $fname ] );
2649                 } catch ( Exception $e ) {
2650                         $this->rollback( $fname, self::FLUSHING_INTERNAL );
2651                         throw $e;
2652                 }
2653                 $this->endAtomic( $fname );
2654
2655                 return $res;
2656         }
2657
2658         final public function begin( $fname = __METHOD__, $mode = self::TRANSACTION_EXPLICIT ) {
2659                 // Protect against mismatched atomic section, transaction nesting, and snapshot loss
2660                 if ( $this->mTrxLevel ) {
2661                         if ( $this->mTrxAtomicLevels ) {
2662                                 $levels = implode( ', ', $this->mTrxAtomicLevels );
2663                                 $msg = "$fname: Got explicit BEGIN while atomic section(s) $levels are open.";
2664                                 throw new DBUnexpectedError( $this, $msg );
2665                         } elseif ( !$this->mTrxAutomatic ) {
2666                                 $msg = "$fname: Explicit transaction already active (from {$this->mTrxFname}).";
2667                                 throw new DBUnexpectedError( $this, $msg );
2668                         } else {
2669                                 // @TODO: make this an exception at some point
2670                                 $msg = "$fname: Implicit transaction already active (from {$this->mTrxFname}).";
2671                                 $this->queryLogger->error( $msg );
2672                                 return; // join the main transaction set
2673                         }
2674                 } elseif ( $this->getFlag( self::DBO_TRX ) && $mode !== self::TRANSACTION_INTERNAL ) {
2675                         // @TODO: make this an exception at some point
2676                         $msg = "$fname: Implicit transaction expected (DBO_TRX set).";
2677                         $this->queryLogger->error( $msg );
2678                         return; // let any writes be in the main transaction
2679                 }
2680
2681                 // Avoid fatals if close() was called
2682                 $this->assertOpen();
2683
2684                 $this->doBegin( $fname );
2685                 $this->mTrxTimestamp = microtime( true );
2686                 $this->mTrxFname = $fname;
2687                 $this->mTrxDoneWrites = false;
2688                 $this->mTrxAutomaticAtomic = false;
2689                 $this->mTrxAtomicLevels = [];
2690                 $this->mTrxShortId = sprintf( '%06x', mt_rand( 0, 0xffffff ) );
2691                 $this->mTrxWriteDuration = 0.0;
2692                 $this->mTrxWriteQueryCount = 0;
2693                 $this->mTrxWriteAdjDuration = 0.0;
2694                 $this->mTrxWriteAdjQueryCount = 0;
2695                 $this->mTrxWriteCallers = [];
2696                 // First SELECT after BEGIN will establish the snapshot in REPEATABLE-READ.
2697                 // Get an estimate of the replica DB lag before then, treating estimate staleness
2698                 // as lag itself just to be safe
2699                 $status = $this->getApproximateLagStatus();
2700                 $this->mTrxReplicaLag = $status['lag'] + ( microtime( true ) - $status['since'] );
2701                 // T147697: make explicitTrxActive() return true until begin() finishes. This way, no
2702                 // caller will think its OK to muck around with the transaction just because startAtomic()
2703                 // has not yet completed (e.g. setting mTrxAtomicLevels).
2704                 $this->mTrxAutomatic = ( $mode === self::TRANSACTION_INTERNAL );
2705         }
2706
2707         /**
2708          * Issues the BEGIN command to the database server.
2709          *
2710          * @see Database::begin()
2711          * @param string $fname
2712          */
2713         protected function doBegin( $fname ) {
2714                 $this->query( 'BEGIN', $fname );
2715                 $this->mTrxLevel = 1;
2716         }
2717
2718         final public function commit( $fname = __METHOD__, $flush = '' ) {
2719                 if ( $this->mTrxLevel && $this->mTrxAtomicLevels ) {
2720                         // There are still atomic sections open. This cannot be ignored
2721                         $levels = implode( ', ', $this->mTrxAtomicLevels );
2722                         throw new DBUnexpectedError(
2723                                 $this,
2724                                 "$fname: Got COMMIT while atomic sections $levels are still open."
2725                         );
2726                 }
2727
2728                 if ( $flush === self::FLUSHING_INTERNAL || $flush === self::FLUSHING_ALL_PEERS ) {
2729                         if ( !$this->mTrxLevel ) {
2730                                 return; // nothing to do
2731                         } elseif ( !$this->mTrxAutomatic ) {
2732                                 throw new DBUnexpectedError(
2733                                         $this,
2734                                         "$fname: Flushing an explicit transaction, getting out of sync."
2735                                 );
2736                         }
2737                 } else {
2738                         if ( !$this->mTrxLevel ) {
2739                                 $this->queryLogger->error(
2740                                         "$fname: No transaction to commit, something got out of sync." );
2741                                 return; // nothing to do
2742                         } elseif ( $this->mTrxAutomatic ) {
2743                                 // @TODO: make this an exception at some point
2744                                 $msg = "$fname: Explicit commit of implicit transaction.";
2745                                 $this->queryLogger->error( $msg );
2746                                 return; // wait for the main transaction set commit round
2747                         }
2748                 }
2749
2750                 // Avoid fatals if close() was called
2751                 $this->assertOpen();
2752
2753                 $this->runOnTransactionPreCommitCallbacks();
2754                 $writeTime = $this->pendingWriteQueryDuration( self::ESTIMATE_DB_APPLY );
2755                 $this->doCommit( $fname );
2756                 if ( $this->mTrxDoneWrites ) {
2757                         $this->mLastWriteTime = microtime( true );
2758                         $this->trxProfiler->transactionWritingOut(
2759                                 $this->mServer, $this->mDBname, $this->mTrxShortId, $writeTime );
2760                 }
2761
2762                 $this->runOnTransactionIdleCallbacks( self::TRIGGER_COMMIT );
2763                 $this->runTransactionListenerCallbacks( self::TRIGGER_COMMIT );
2764         }
2765
2766         /**
2767          * Issues the COMMIT command to the database server.
2768          *
2769          * @see Database::commit()
2770          * @param string $fname
2771          */
2772         protected function doCommit( $fname ) {
2773                 if ( $this->mTrxLevel ) {
2774                         $this->query( 'COMMIT', $fname );
2775                         $this->mTrxLevel = 0;
2776                 }
2777         }
2778
2779         final public function rollback( $fname = __METHOD__, $flush = '' ) {
2780                 if ( $flush === self::FLUSHING_INTERNAL || $flush === self::FLUSHING_ALL_PEERS ) {
2781                         if ( !$this->mTrxLevel ) {
2782                                 return; // nothing to do
2783                         }
2784                 } else {
2785                         if ( !$this->mTrxLevel ) {
2786                                 $this->queryLogger->error(
2787                                         "$fname: No transaction to rollback, something got out of sync." );
2788                                 return; // nothing to do
2789                         } elseif ( $this->getFlag( self::DBO_TRX ) ) {
2790                                 throw new DBUnexpectedError(
2791                                         $this,
2792                                         "$fname: Expected mass rollback of all peer databases (DBO_TRX set)."
2793                                 );
2794                         }
2795                 }
2796
2797                 // Avoid fatals if close() was called
2798                 $this->assertOpen();
2799
2800                 $this->doRollback( $fname );
2801                 $this->mTrxAtomicLevels = [];
2802                 if ( $this->mTrxDoneWrites ) {
2803                         $this->trxProfiler->transactionWritingOut(
2804                                 $this->mServer, $this->mDBname, $this->mTrxShortId );
2805                 }
2806
2807                 $this->mTrxIdleCallbacks = []; // clear
2808                 $this->mTrxPreCommitCallbacks = []; // clear
2809                 $this->runOnTransactionIdleCallbacks( self::TRIGGER_ROLLBACK );
2810                 $this->runTransactionListenerCallbacks( self::TRIGGER_ROLLBACK );
2811         }
2812
2813         /**
2814          * Issues the ROLLBACK command to the database server.
2815          *
2816          * @see Database::rollback()
2817          * @param string $fname
2818          */
2819         protected function doRollback( $fname ) {
2820                 if ( $this->mTrxLevel ) {
2821                         # Disconnects cause rollback anyway, so ignore those errors
2822                         $ignoreErrors = true;
2823                         $this->query( 'ROLLBACK', $fname, $ignoreErrors );
2824                         $this->mTrxLevel = 0;
2825                 }
2826         }
2827
2828         public function flushSnapshot( $fname = __METHOD__ ) {
2829                 if ( $this->writesOrCallbacksPending() || $this->explicitTrxActive() ) {
2830                         // This only flushes transactions to clear snapshots, not to write data
2831                         $fnames = implode( ', ', $this->pendingWriteAndCallbackCallers() );
2832                         throw new DBUnexpectedError(
2833                                 $this,
2834                                 "$fname: Cannot flush snapshot because writes are pending ($fnames)."
2835                         );
2836                 }
2837
2838                 $this->commit( $fname, self::FLUSHING_INTERNAL );
2839         }
2840
2841         public function explicitTrxActive() {
2842                 return $this->mTrxLevel && ( $this->mTrxAtomicLevels || !$this->mTrxAutomatic );
2843         }
2844
2845         /**
2846          * Creates a new table with structure copied from existing table
2847          * Note that unlike most database abstraction functions, this function does not
2848          * automatically append database prefix, because it works at a lower
2849          * abstraction level.
2850          * The table names passed to this function shall not be quoted (this
2851          * function calls addIdentifierQuotes when needed).
2852          *
2853          * @param string $oldName Name of table whose structure should be copied
2854          * @param string $newName Name of table to be created
2855          * @param bool $temporary Whether the new table should be temporary
2856          * @param string $fname Calling function name
2857          * @throws RuntimeException
2858          * @return bool True if operation was successful
2859          */
2860         public function duplicateTableStructure( $oldName, $newName, $temporary = false,
2861                 $fname = __METHOD__
2862         ) {
2863                 throw new RuntimeException( __METHOD__ . ' is not implemented in descendant class' );
2864         }
2865
2866         public function listTables( $prefix = null, $fname = __METHOD__ ) {
2867                 throw new RuntimeException( __METHOD__ . ' is not implemented in descendant class' );
2868         }
2869
2870         public function listViews( $prefix = null, $fname = __METHOD__ ) {
2871                 throw new RuntimeException( __METHOD__ . ' is not implemented in descendant class' );
2872         }
2873
2874         public function timestamp( $ts = 0 ) {
2875                 $t = new ConvertibleTimestamp( $ts );
2876                 // Let errors bubble up to avoid putting garbage in the DB
2877                 return $t->getTimestamp( TS_MW );
2878         }
2879
2880         public function timestampOrNull( $ts = null ) {
2881                 if ( is_null( $ts ) ) {
2882                         return null;
2883                 } else {
2884                         return $this->timestamp( $ts );
2885                 }
2886         }
2887
2888         /**
2889          * Take the result from a query, and wrap it in a ResultWrapper if
2890          * necessary. Boolean values are passed through as is, to indicate success
2891          * of write queries or failure.
2892          *
2893          * Once upon a time, Database::query() returned a bare MySQL result
2894          * resource, and it was necessary to call this function to convert it to
2895          * a wrapper. Nowadays, raw database objects are never exposed to external
2896          * callers, so this is unnecessary in external code.
2897          *
2898          * @param bool|ResultWrapper|resource|object $result
2899          * @return bool|ResultWrapper
2900          */
2901         protected function resultObject( $result ) {
2902                 if ( !$result ) {
2903                         return false;
2904                 } elseif ( $result instanceof ResultWrapper ) {
2905                         return $result;
2906                 } elseif ( $result === true ) {
2907                         // Successful write query
2908                         return $result;
2909                 } else {
2910                         return new ResultWrapper( $this, $result );
2911                 }
2912         }
2913
2914         public function ping( &$rtt = null ) {
2915                 // Avoid hitting the server if it was hit recently
2916                 if ( $this->isOpen() && ( microtime( true ) - $this->lastPing ) < self::PING_TTL ) {
2917                         if ( !func_num_args() || $this->mRTTEstimate > 0 ) {
2918                                 $rtt = $this->mRTTEstimate;
2919                                 return true; // don't care about $rtt
2920                         }
2921                 }
2922
2923                 // This will reconnect if possible or return false if not
2924                 $this->clearFlag( self::DBO_TRX, self::REMEMBER_PRIOR );
2925                 $ok = ( $this->query( self::PING_QUERY, __METHOD__, true ) !== false );
2926                 $this->restoreFlags( self::RESTORE_PRIOR );
2927
2928                 if ( $ok ) {
2929                         $rtt = $this->mRTTEstimate;
2930                 }
2931
2932                 return $ok;
2933         }
2934
2935         /**
2936          * @return bool
2937          */
2938         protected function reconnect() {
2939                 $this->closeConnection();
2940                 $this->mOpened = false;
2941                 $this->mConn = false;
2942                 try {
2943                         $this->open( $this->mServer, $this->mUser, $this->mPassword, $this->mDBname );
2944                         $this->lastPing = microtime( true );
2945                         $ok = true;
2946                 } catch ( DBConnectionError $e ) {
2947                         $ok = false;
2948                 }
2949
2950                 return $ok;
2951         }
2952
2953         public function getSessionLagStatus() {
2954                 return $this->getTransactionLagStatus() ?: $this->getApproximateLagStatus();
2955         }
2956
2957         /**
2958          * Get the replica DB lag when the current transaction started
2959          *
2960          * This is useful when transactions might use snapshot isolation
2961          * (e.g. REPEATABLE-READ in innodb), so the "real" lag of that data
2962          * is this lag plus transaction duration. If they don't, it is still
2963          * safe to be pessimistic. This returns null if there is no transaction.
2964          *
2965          * @return array|null ('lag': seconds or false on error, 'since': UNIX timestamp of BEGIN)
2966          * @since 1.27
2967          */
2968         protected function getTransactionLagStatus() {
2969                 return $this->mTrxLevel
2970                         ? [ 'lag' => $this->mTrxReplicaLag, 'since' => $this->trxTimestamp() ]
2971                         : null;
2972         }
2973
2974         /**
2975          * Get a replica DB lag estimate for this server
2976          *
2977          * @return array ('lag': seconds or false on error, 'since': UNIX timestamp of estimate)
2978          * @since 1.27
2979          */
2980         protected function getApproximateLagStatus() {
2981                 return [
2982                         'lag'   => $this->getLBInfo( 'replica' ) ? $this->getLag() : 0,
2983                         'since' => microtime( true )
2984                 ];
2985         }
2986
2987         /**
2988          * Merge the result of getSessionLagStatus() for several DBs
2989          * using the most pessimistic values to estimate the lag of
2990          * any data derived from them in combination
2991          *
2992          * This is information is useful for caching modules
2993          *
2994          * @see WANObjectCache::set()
2995          * @see WANObjectCache::getWithSetCallback()
2996          *
2997          * @param IDatabase $db1
2998          * @param IDatabase ...
2999          * @return array Map of values:
3000          *   - lag: highest lag of any of the DBs or false on error (e.g. replication stopped)
3001          *   - since: oldest UNIX timestamp of any of the DB lag estimates
3002          *   - pending: whether any of the DBs have uncommitted changes
3003          * @since 1.27
3004          */
3005         public static function getCacheSetOptions( IDatabase $db1 ) {
3006                 $res = [ 'lag' => 0, 'since' => INF, 'pending' => false ];
3007                 foreach ( func_get_args() as $db ) {
3008                         /** @var IDatabase $db */
3009                         $status = $db->getSessionLagStatus();
3010                         if ( $status['lag'] === false ) {
3011                                 $res['lag'] = false;
3012                         } elseif ( $res['lag'] !== false ) {
3013                                 $res['lag'] = max( $res['lag'], $status['lag'] );
3014                         }
3015                         $res['since'] = min( $res['since'], $status['since'] );
3016                         $res['pending'] = $res['pending'] ?: $db->writesPending();
3017                 }
3018
3019                 return $res;
3020         }
3021
3022         public function getLag() {
3023                 return 0;
3024         }
3025
3026         public function maxListLen() {
3027                 return 0;
3028         }
3029
3030         public function encodeBlob( $b ) {
3031                 return $b;
3032         }
3033
3034         public function decodeBlob( $b ) {
3035                 if ( $b instanceof Blob ) {
3036                         $b = $b->fetch();
3037                 }
3038                 return $b;
3039         }
3040
3041         public function setSessionOptions( array $options ) {
3042         }
3043
3044         public function sourceFile(
3045                 $filename,
3046                 callable $lineCallback = null,
3047                 callable $resultCallback = null,
3048                 $fname = false,
3049                 callable $inputCallback = null
3050         ) {
3051                 MediaWiki\suppressWarnings();
3052                 $fp = fopen( $filename, 'r' );
3053                 MediaWiki\restoreWarnings();
3054
3055                 if ( false === $fp ) {
3056                         throw new RuntimeException( "Could not open \"{$filename}\".\n" );
3057                 }
3058
3059                 if ( !$fname ) {
3060                         $fname = __METHOD__ . "( $filename )";
3061                 }
3062
3063                 try {
3064                         $error = $this->sourceStream(
3065                                 $fp, $lineCallback, $resultCallback, $fname, $inputCallback );
3066                 } catch ( Exception $e ) {
3067                         fclose( $fp );
3068                         throw $e;
3069                 }
3070
3071                 fclose( $fp );
3072
3073                 return $error;
3074         }
3075
3076         public function setSchemaVars( $vars ) {
3077                 $this->mSchemaVars = $vars;
3078         }
3079
3080         public function sourceStream(
3081                 $fp,
3082                 callable $lineCallback = null,
3083                 callable $resultCallback = null,
3084                 $fname = __METHOD__,
3085                 callable $inputCallback = null
3086         ) {
3087                 $cmd = '';
3088
3089                 while ( !feof( $fp ) ) {
3090                         if ( $lineCallback ) {
3091                                 call_user_func( $lineCallback );
3092                         }
3093
3094                         $line = trim( fgets( $fp ) );
3095
3096                         if ( $line == '' ) {
3097                                 continue;
3098                         }
3099
3100                         if ( '-' == $line[0] && '-' == $line[1] ) {
3101                                 continue;
3102                         }
3103
3104                         if ( $cmd != '' ) {
3105                                 $cmd .= ' ';
3106                         }
3107
3108                         $done = $this->streamStatementEnd( $cmd, $line );
3109
3110                         $cmd .= "$line\n";
3111
3112                         if ( $done || feof( $fp ) ) {
3113                                 $cmd = $this->replaceVars( $cmd );
3114
3115                                 if ( !$inputCallback || call_user_func( $inputCallback, $cmd ) ) {
3116                                         $res = $this->query( $cmd, $fname );
3117
3118                                         if ( $resultCallback ) {
3119                                                 call_user_func( $resultCallback, $res, $this );
3120                                         }
3121
3122                                         if ( false === $res ) {
3123                                                 $err = $this->lastError();
3124
3125                                                 return "Query \"{$cmd}\" failed with error code \"$err\".\n";
3126                                         }
3127                                 }
3128                                 $cmd = '';
3129                         }
3130                 }
3131
3132                 return true;
3133         }
3134
3135         /**
3136          * Called by sourceStream() to check if we've reached a statement end
3137          *
3138          * @param string &$sql SQL assembled so far
3139          * @param string &$newLine New line about to be added to $sql
3140          * @return bool Whether $newLine contains end of the statement
3141          */
3142         public function streamStatementEnd( &$sql, &$newLine ) {
3143                 if ( $this->delimiter ) {
3144                         $prev = $newLine;
3145                         $newLine = preg_replace(
3146                                 '/' . preg_quote( $this->delimiter, '/' ) . '$/', '', $newLine );
3147                         if ( $newLine != $prev ) {
3148                                 return true;
3149                         }
3150                 }
3151
3152                 return false;
3153         }
3154
3155         /**
3156          * Database independent variable replacement. Replaces a set of variables
3157          * in an SQL statement with their contents as given by $this->getSchemaVars().
3158          *
3159          * Supports '{$var}' `{$var}` and / *$var* / (without the spaces) style variables.
3160          *
3161          * - '{$var}' should be used for text and is passed through the database's
3162          *   addQuotes method.
3163          * - `{$var}` should be used for identifiers (e.g. table and database names).
3164          *   It is passed through the database's addIdentifierQuotes method which
3165          *   can be overridden if the database uses something other than backticks.
3166          * - / *_* / or / *$wgDBprefix* / passes the name that follows through the
3167          *   database's tableName method.
3168          * - / *i* / passes the name that follows through the database's indexName method.
3169          * - In all other cases, / *$var* / is left unencoded. Except for table options,
3170          *   its use should be avoided. In 1.24 and older, string encoding was applied.
3171          *
3172          * @param string $ins SQL statement to replace variables in
3173          * @return string The new SQL statement with variables replaced
3174          */
3175         protected function replaceVars( $ins ) {
3176                 $vars = $this->getSchemaVars();
3177                 return preg_replace_callback(
3178                         '!
3179                                 /\* (\$wgDBprefix|[_i]) \*/ (\w*) | # 1-2. tableName, indexName
3180                                 \'\{\$ (\w+) }\'                  | # 3. addQuotes
3181                                 `\{\$ (\w+) }`                    | # 4. addIdentifierQuotes
3182                                 /\*\$ (\w+) \*/                     # 5. leave unencoded
3183                         !x',
3184                         function ( $m ) use ( $vars ) {
3185                                 // Note: Because of <https://bugs.php.net/bug.php?id=51881>,
3186                                 // check for both nonexistent keys *and* the empty string.
3187                                 if ( isset( $m[1] ) && $m[1] !== '' ) {
3188                                         if ( $m[1] === 'i' ) {
3189                                                 return $this->indexName( $m[2] );
3190                                         } else {
3191                                                 return $this->tableName( $m[2] );
3192                                         }
3193                                 } elseif ( isset( $m[3] ) && $m[3] !== '' && array_key_exists( $m[3], $vars ) ) {
3194                                         return $this->addQuotes( $vars[$m[3]] );
3195                                 } elseif ( isset( $m[4] ) && $m[4] !== '' && array_key_exists( $m[4], $vars ) ) {
3196                                         return $this->addIdentifierQuotes( $vars[$m[4]] );
3197                                 } elseif ( isset( $m[5] ) && $m[5] !== '' && array_key_exists( $m[5], $vars ) ) {
3198                                         return $vars[$m[5]];
3199                                 } else {
3200                                         return $m[0];
3201                                 }
3202                         },
3203                         $ins
3204                 );
3205         }
3206
3207         /**
3208          * Get schema variables. If none have been set via setSchemaVars(), then
3209          * use some defaults from the current object.
3210          *
3211          * @return array
3212          */
3213         protected function getSchemaVars() {
3214                 if ( $this->mSchemaVars ) {
3215                         return $this->mSchemaVars;
3216                 } else {
3217                         return $this->getDefaultSchemaVars();
3218                 }
3219         }
3220
3221         /**
3222          * Get schema variables to use if none have been set via setSchemaVars().
3223          *
3224          * Override this in derived classes to provide variables for tables.sql
3225          * and SQL patch files.
3226          *
3227          * @return array
3228          */
3229         protected function getDefaultSchemaVars() {
3230                 return [];
3231         }
3232
3233         public function lockIsFree( $lockName, $method ) {
3234                 return true;
3235         }
3236
3237         public function lock( $lockName, $method, $timeout = 5 ) {
3238                 $this->mNamedLocksHeld[$lockName] = 1;
3239
3240                 return true;
3241         }
3242
3243         public function unlock( $lockName, $method ) {
3244                 unset( $this->mNamedLocksHeld[$lockName] );
3245
3246                 return true;
3247         }
3248
3249         public function getScopedLockAndFlush( $lockKey, $fname, $timeout ) {
3250                 if ( $this->writesOrCallbacksPending() ) {
3251                         // This only flushes transactions to clear snapshots, not to write data
3252                         $fnames = implode( ', ', $this->pendingWriteAndCallbackCallers() );
3253                         throw new DBUnexpectedError(
3254                                 $this,
3255                                 "$fname: Cannot flush pre-lock snapshot because writes are pending ($fnames)."
3256                         );
3257                 }
3258
3259                 if ( !$this->lock( $lockKey, $fname, $timeout ) ) {
3260                         return null;
3261                 }
3262
3263                 $unlocker = new ScopedCallback( function () use ( $lockKey, $fname ) {
3264                         if ( $this->trxLevel() ) {
3265                                 // There is a good chance an exception was thrown, causing any early return
3266                                 // from the caller. Let any error handler get a chance to issue rollback().
3267                                 // If there isn't one, let the error bubble up and trigger server-side rollback.
3268                                 $this->onTransactionResolution(
3269                                         function () use ( $lockKey, $fname ) {
3270                                                 $this->unlock( $lockKey, $fname );
3271                                         },
3272                                         $fname
3273                                 );
3274                         } else {
3275                                 $this->unlock( $lockKey, $fname );
3276                         }
3277                 } );
3278
3279                 $this->commit( $fname, self::FLUSHING_INTERNAL );
3280
3281                 return $unlocker;
3282         }
3283
3284         public function namedLocksEnqueue() {
3285                 return false;
3286         }
3287
3288         /**
3289          * Lock specific tables
3290          *
3291          * @param array $read Array of tables to lock for read access
3292          * @param array $write Array of tables to lock for write access
3293          * @param string $method Name of caller
3294          * @param bool $lowPriority Whether to indicate writes to be LOW PRIORITY
3295          * @return bool
3296          */
3297         public function lockTables( $read, $write, $method, $lowPriority = true ) {
3298                 return true;
3299         }
3300
3301         /**
3302          * Unlock specific tables
3303          *
3304          * @param string $method The caller
3305          * @return bool
3306          */
3307         public function unlockTables( $method ) {
3308                 return true;
3309         }
3310
3311         /**
3312          * Delete a table
3313          * @param string $tableName
3314          * @param string $fName
3315          * @return bool|ResultWrapper
3316          * @since 1.18
3317          */
3318         public function dropTable( $tableName, $fName = __METHOD__ ) {
3319                 if ( !$this->tableExists( $tableName, $fName ) ) {
3320                         return false;
3321                 }
3322                 $sql = "DROP TABLE " . $this->tableName( $tableName ) . " CASCADE";
3323
3324                 return $this->query( $sql, $fName );
3325         }
3326
3327         public function getInfinity() {
3328                 return 'infinity';
3329         }
3330
3331         public function encodeExpiry( $expiry ) {
3332                 return ( $expiry == '' || $expiry == 'infinity' || $expiry == $this->getInfinity() )
3333                         ? $this->getInfinity()
3334                         : $this->timestamp( $expiry );
3335         }
3336
3337         public function decodeExpiry( $expiry, $format = TS_MW ) {
3338                 if ( $expiry == '' || $expiry == 'infinity' || $expiry == $this->getInfinity() ) {
3339                         return 'infinity';
3340                 }
3341
3342                 return ConvertibleTimestamp::convert( $format, $expiry );
3343         }
3344
3345         public function setBigSelects( $value = true ) {
3346                 // no-op
3347         }
3348
3349         public function isReadOnly() {
3350                 return ( $this->getReadOnlyReason() !== false );
3351         }
3352
3353         /**
3354          * @return string|bool Reason this DB is read-only or false if it is not
3355          */
3356         protected function getReadOnlyReason() {
3357                 $reason = $this->getLBInfo( 'readOnlyReason' );
3358
3359                 return is_string( $reason ) ? $reason : false;
3360         }
3361
3362         public function setTableAliases( array $aliases ) {
3363                 $this->tableAliases = $aliases;
3364         }
3365
3366         /**
3367          * @return bool Whether a DB user is required to access the DB
3368          * @since 1.28
3369          */
3370         protected function requiresDatabaseUser() {
3371                 return true;
3372         }
3373
3374         /**
3375          * Get the underlying binding handle, mConn
3376          *
3377          * Makes sure that mConn is set (disconnects and ping() failure can unset it).
3378          * This catches broken callers than catch and ignore disconnection exceptions.
3379          * Unlike checking isOpen(), this is safe to call inside of open().
3380          *
3381          * @return resource|object
3382          * @throws DBUnexpectedError
3383          * @since 1.26
3384          */
3385         protected function getBindingHandle() {
3386                 if ( !$this->mConn ) {
3387                         throw new DBUnexpectedError(
3388                                 $this,
3389                                 'DB connection was already closed or the connection dropped.'
3390                         );
3391                 }
3392
3393                 return $this->mConn;
3394         }
3395
3396         /**
3397          * @since 1.19
3398          * @return string
3399          */
3400         public function __toString() {
3401                 return (string)$this->mConn;
3402         }
3403
3404         /**
3405          * Make sure that copies do not share the same client binding handle
3406          * @throws DBConnectionError
3407          */
3408         public function __clone() {
3409                 $this->connLogger->warning(
3410                         "Cloning " . get_class( $this ) . " is not recomended; forking connection:\n" .
3411                         ( new RuntimeException() )->getTraceAsString()
3412                 );
3413
3414                 if ( $this->isOpen() ) {
3415                         // Open a new connection resource without messing with the old one
3416                         $this->mOpened = false;
3417                         $this->mConn = false;
3418                         $this->mTrxEndCallbacks = []; // don't copy
3419                         $this->handleSessionLoss(); // no trx or locks anymore
3420                         $this->open( $this->mServer, $this->mUser, $this->mPassword, $this->mDBname );
3421                         $this->lastPing = microtime( true );
3422                 }
3423         }
3424
3425         /**
3426          * Called by serialize. Throw an exception when DB connection is serialized.
3427          * This causes problems on some database engines because the connection is
3428          * not restored on unserialize.
3429          */
3430         public function __sleep() {
3431                 throw new RuntimeException( 'Database serialization may cause problems, since ' .
3432                         'the connection is not restored on wakeup.' );
3433         }
3434
3435         /**
3436          * Run a few simple sanity checks and close dangling connections
3437          */
3438         public function __destruct() {
3439                 if ( $this->mTrxLevel && $this->mTrxDoneWrites ) {
3440                         trigger_error( "Uncommitted DB writes (transaction from {$this->mTrxFname})." );
3441                 }
3442
3443                 $danglingWriters = $this->pendingWriteAndCallbackCallers();
3444                 if ( $danglingWriters ) {
3445                         $fnames = implode( ', ', $danglingWriters );
3446                         trigger_error( "DB transaction writes or callbacks still pending ($fnames)." );
3447                 }
3448
3449                 if ( $this->mConn ) {
3450                         // Avoid connection leaks for sanity. Normally, resources close at script completion.
3451                         // The connection might already be closed in zend/hhvm by now, so suppress warnings.
3452                         \MediaWiki\suppressWarnings();
3453                         $this->closeConnection();
3454                         \MediaWiki\restoreWarnings();
3455                         $this->mConn = false;
3456                         $this->mOpened = false;
3457                 }
3458         }
3459 }
3460
3461 class_alias( 'Database', 'DatabaseBase' );