includes/libs/rdbms/database/DatabaseSqlite.php

   1 <?php
   2 /**
   3  * This is the SQLite database abstraction layer.
   4  * See maintenance/sqlite/README for development notes and other specific information
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License along
  17  * with this program; if not, write to the Free Software Foundation, Inc.,
  18  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  19  * http://www.gnu.org/copyleft/gpl.html
  20  *
  21  * @file
  22  * @ingroup Database
  23  */
  24 namespace Wikimedia\Rdbms;
  25
  26 use PDO;
  27 use PDOException;
  28 use LockManager;
  29 use FSLockManager;
  30 use InvalidArgumentException;
  31 use RuntimeException;
  32 use stdClass;
  33
  34 /**
  35  * @ingroup Database
  36  */
  37 class DatabaseSqlite extends Database {
  38         /** @var bool Whether full text is enabled */
  39         private static $fulltextEnabled = null;
  40
  41         /** @var string Directory */
  42         protected $dbDir;
  43         /** @var string File name for SQLite database file */
  44         protected $dbPath;
  45         /** @var string Transaction mode */
  46         protected $trxMode;
  47
  48         /** @var int The number of rows affected as an integer */
  49         protected $lastAffectedRowCount;
  50         /** @var resource */
  51         protected $lastResultHandle;
  52
  53         /** @var PDO */
  54         protected $conn;
  55
  56         /** @var FSLockManager (hopefully on the same server as the DB) */
  57         protected $lockMgr;
  58
  59         /** @var array List of shared database already attached to this connection */
  60         private $alreadyAttached = [];
  61
  62         /**
  63          * Additional params include:
  64          *   - dbDirectory : directory containing the DB and the lock file directory
  65          *                   [defaults to $wgSQLiteDataDir]
  66          *   - dbFilePath  : use this to force the path of the DB file
  67          *   - trxMode     : one of (deferred, immediate, exclusive)
  68          * @param array $p
  69          */
  70         function __construct( array $p ) {
  71                 if ( isset( $p['dbFilePath'] ) ) {
  72                         $this->dbPath = $p['dbFilePath'];
  73                         $lockDomain = md5( $this->dbPath );
  74                 } elseif ( isset( $p['dbDirectory'] ) ) {
  75                         $this->dbDir = $p['dbDirectory'];
  76                         $lockDomain = $p['dbname'];
  77                 } else {
  78                         throw new InvalidArgumentException( "Need 'dbDirectory' or 'dbFilePath' parameter." );
  79                 }
  80
  81                 $this->trxMode = isset( $p['trxMode'] ) ? strtoupper( $p['trxMode'] ) : null;
  82                 if ( $this->trxMode &&
  83                         !in_array( $this->trxMode, [ 'DEFERRED', 'IMMEDIATE', 'EXCLUSIVE' ] )
  84                 ) {
  85                         $this->trxMode = null;
  86                         $this->queryLogger->warning( "Invalid SQLite transaction mode provided." );
  87                 }
  88
  89                 $this->lockMgr = new FSLockManager( [
  90                         'domain' => $lockDomain,
  91                         'lockDirectory' => "{$this->dbDir}/locks"
  92                 ] );
  93
  94                 parent::__construct( $p );
  95         }
  96
  97         protected static function getAttributes() {
  98                 return [ self::ATTR_DB_LEVEL_LOCKING => true ];
  99         }
 100
 101         /**
 102          * @param string $filename
 103          * @param array $p Options map; supports:
 104          *   - flags       : (same as __construct counterpart)
 105          *   - trxMode     : (same as __construct counterpart)
 106          *   - dbDirectory : (same as __construct counterpart)
 107          * @return DatabaseSqlite
 108          * @since 1.25
 109          */
 110         public static function newStandaloneInstance( $filename, array $p = [] ) {
 111                 $p['dbFilePath'] = $filename;
 112                 $p['schema'] = false;
 113                 $p['tablePrefix'] = '';
 114                 /** @var DatabaseSqlite $db */
 115                 $db = Database::factory( 'sqlite', $p );
 116
 117                 return $db;
 118         }
 119
 120         protected function doInitConnection() {
 121                 if ( $this->dbPath !== null ) {
 122                         // Standalone .sqlite file mode.
 123                         $this->openFile( $this->dbPath, $this->connectionParams['dbname'] );
 124                 } elseif ( $this->dbDir !== null ) {
 125                         // Stock wiki mode using standard file names per DB
 126                         if ( strlen( $this->connectionParams['dbname'] ) ) {
 127                                 $this->open(
 128                                         $this->connectionParams['host'],
 129                                         $this->connectionParams['user'],
 130                                         $this->connectionParams['password'],
 131                                         $this->connectionParams['dbname']
 132                                 );
 133                         } else {
 134                                 // Caller will manually call open() later?
 135                                 $this->connLogger->debug( __METHOD__ . ': no database opened.' );
 136                         }
 137                 } else {
 138                         throw new InvalidArgumentException( "Need 'dbDirectory' or 'dbFilePath' parameter." );
 139                 }
 140         }
 141
 142         /**
 143          * @return string
 144          */
 145         function getType() {
 146                 return 'sqlite';
 147         }
 148
 149         /**
 150          * @todo Check if it should be true like parent class
 151          *
 152          * @return bool
 153          */
 154         function implicitGroupby() {
 155                 return false;
 156         }
 157
 158         /** Open an SQLite database and return a resource handle to it
 159          *  NOTE: only $dbName is used, the other parameters are irrelevant for SQLite databases
 160          *
 161          * @param string $server
 162          * @param string $user Unused
 163          * @param string $pass
 164          * @param string $dbName
 165          *
 166          * @throws DBConnectionError
 167          * @return bool
 168          */
 169         function open( $server, $user, $pass, $dbName ) {
 170                 $this->close();
 171                 $fileName = self::generateFileName( $this->dbDir, $dbName );
 172                 if ( !is_readable( $fileName ) ) {
 173                         $this->conn = false;
 174                         throw new DBConnectionError( $this, "SQLite database not accessible" );
 175                 }
 176                 $this->openFile( $fileName, $dbName );
 177
 178                 return (bool)$this->conn;
 179         }
 180
 181         /**
 182          * Opens a database file
 183          *
 184          * @param string $fileName
 185          * @param string $dbName
 186          * @throws DBConnectionError
 187          * @return PDO|bool SQL connection or false if failed
 188          */
 189         protected function openFile( $fileName, $dbName ) {
 190                 $err = false;
 191
 192                 $this->dbPath = $fileName;
 193                 try {
 194                         if ( $this->flags & self::DBO_PERSISTENT ) {
 195                                 $this->conn = new PDO( "sqlite:$fileName", '', '',
 196                                         [ PDO::ATTR_PERSISTENT => true ] );
 197                         } else {
 198                                 $this->conn = new PDO( "sqlite:$fileName", '', '' );
 199                         }
 200                 } catch ( PDOException $e ) {
 201                         $err = $e->getMessage();
 202                 }
 203
 204                 if ( !$this->conn ) {
 205                         $this->queryLogger->debug( "DB connection error: $err\n" );
 206                         throw new DBConnectionError( $this, $err );
 207                 }
 208
 209                 $this->opened = is_object( $this->conn );
 210                 if ( $this->opened ) {
 211                         $this->dbName = $dbName;
 212                         # Set error codes only, don't raise exceptions
 213                         $this->conn->setAttribute( PDO::ATTR_ERRMODE, PDO::ERRMODE_SILENT );
 214                         # Enforce LIKE to be case sensitive, just like MySQL
 215                         $this->query( 'PRAGMA case_sensitive_like = 1' );
 216
 217                         return $this->conn;
 218                 }
 219
 220                 return false;
 221         }
 222
 223         public function selectDB( $db ) {
 224                 return false; // doesn't make sense
 225         }
 226
 227         /**
 228          * @return string SQLite DB file path
 229          * @since 1.25
 230          */
 231         public function getDbFilePath() {
 232                 return $this->dbPath;
 233         }
 234
 235         /**
 236          * Does not actually close the connection, just destroys the reference for GC to do its work
 237          * @return bool
 238          */
 239         protected function closeConnection() {
 240                 $this->conn = null;
 241
 242                 return true;
 243         }
 244
 245         /**
 246          * Generates a database file name. Explicitly public for installer.
 247          * @param string $dir Directory where database resides
 248          * @param string $dbName Database name
 249          * @return string
 250          */
 251         public static function generateFileName( $dir, $dbName ) {
 252                 return "$dir/$dbName.sqlite";
 253         }
 254
 255         /**
 256          * Check if the searchindext table is FTS enabled.
 257          * @return bool False if not enabled.
 258          */
 259         function checkForEnabledSearch() {
 260                 if ( self::$fulltextEnabled === null ) {
 261                         self::$fulltextEnabled = false;
 262                         $table = $this->tableName( 'searchindex' );
 263                         $res = $this->query( "SELECT sql FROM sqlite_master WHERE tbl_name = '$table'", __METHOD__ );
 264                         if ( $res ) {
 265                                 $row = $res->fetchRow();
 266                                 self::$fulltextEnabled = stristr( $row['sql'], 'fts' ) !== false;
 267                         }
 268                 }
 269
 270                 return self::$fulltextEnabled;
 271         }
 272
 273         /**
 274          * Returns version of currently supported SQLite fulltext search module or false if none present.
 275          * @return string
 276          */
 277         static function getFulltextSearchModule() {
 278                 static $cachedResult = null;
 279                 if ( $cachedResult !== null ) {
 280                         return $cachedResult;
 281                 }
 282                 $cachedResult = false;
 283                 $table = 'dummy_search_test';
 284
 285                 $db = self::newStandaloneInstance( ':memory:' );
 286                 if ( $db->query( "CREATE VIRTUAL TABLE $table USING FTS3(dummy_field)", __METHOD__, true ) ) {
 287                         $cachedResult = 'FTS3';
 288                 }
 289                 $db->close();
 290
 291                 return $cachedResult;
 292         }
 293
 294         /**
 295          * Attaches external database to our connection, see https://sqlite.org/lang_attach.html
 296          * for details.
 297          *
 298          * @param string $name Database name to be used in queries like
 299          *   SELECT foo FROM dbname.table
 300          * @param bool|string $file Database file name. If omitted, will be generated
 301          *   using $name and configured data directory
 302          * @param string $fname Calling function name
 303          * @return ResultWrapper
 304          */
 305         function attachDatabase( $name, $file = false, $fname = __METHOD__ ) {
 306                 if ( !$file ) {
 307                         $file = self::generateFileName( $this->dbDir, $name );
 308                 }
 309                 $file = $this->addQuotes( $file );
 310
 311                 return $this->query( "ATTACH DATABASE $file AS $name", $fname );
 312         }
 313
 314         function isWriteQuery( $sql ) {
 315                 return parent::isWriteQuery( $sql ) && !preg_match( '/^(ATTACH|PRAGMA)\b/i', $sql );
 316         }
 317
 318         protected function isTransactableQuery( $sql ) {
 319                 return parent::isTransactableQuery( $sql ) && !in_array(
 320                         $this->getQueryVerb( $sql ),
 321                         [ 'ATTACH', 'PRAGMA' ],
 322                         true
 323                 );
 324         }
 325
 326         /**
 327          * SQLite doesn't allow buffered results or data seeking etc, so we'll use fetchAll as the result
 328          *
 329          * @param string $sql
 330          * @return bool|ResultWrapper
 331          */
 332         protected function doQuery( $sql ) {
 333                 $res = $this->getBindingHandle()->query( $sql );
 334                 if ( $res === false ) {
 335                         return false;
 336                 }
 337
 338                 $r = $res instanceof ResultWrapper ? $res->result : $res;
 339                 $this->lastAffectedRowCount = $r->rowCount();
 340                 $res = new ResultWrapper( $this, $r->fetchAll() );
 341
 342                 return $res;
 343         }
 344
 345         /**
 346          * @param ResultWrapper|mixed $res
 347          */
 348         function freeResult( $res ) {
 349                 if ( $res instanceof ResultWrapper ) {
 350                         $res->result = null;
 351                 } else {
 352                         $res = null;
 353                 }
 354         }
 355
 356         /**
 357          * @param ResultWrapper|array $res
 358          * @return stdClass|bool
 359          */
 360         function fetchObject( $res ) {
 361                 if ( $res instanceof ResultWrapper ) {
 362                         $r =& $res->result;
 363                 } else {
 364                         $r =& $res;
 365                 }
 366
 367                 $cur = current( $r );
 368                 if ( is_array( $cur ) ) {
 369                         next( $r );
 370                         $obj = new stdClass;
 371                         foreach ( $cur as $k => $v ) {
 372                                 if ( !is_numeric( $k ) ) {
 373                                         $obj->$k = $v;
 374                                 }
 375                         }
 376
 377                         return $obj;
 378                 }
 379
 380                 return false;
 381         }
 382
 383         /**
 384          * @param ResultWrapper|mixed $res
 385          * @return array|bool
 386          */
 387         function fetchRow( $res ) {
 388                 if ( $res instanceof ResultWrapper ) {
 389                         $r =& $res->result;
 390                 } else {
 391                         $r =& $res;
 392                 }
 393                 $cur = current( $r );
 394                 if ( is_array( $cur ) ) {
 395                         next( $r );
 396
 397                         return $cur;
 398                 }
 399
 400                 return false;
 401         }
 402
 403         /**
 404          * The PDO::Statement class implements the array interface so count() will work
 405          *
 406          * @param ResultWrapper|array $res
 407          * @return int
 408          */
 409         function numRows( $res ) {
 410                 $r = $res instanceof ResultWrapper ? $res->result : $res;
 411
 412                 return count( $r );
 413         }
 414
 415         /**
 416          * @param ResultWrapper $res
 417          * @return int
 418          */
 419         function numFields( $res ) {
 420                 $r = $res instanceof ResultWrapper ? $res->result : $res;
 421                 if ( is_array( $r ) && count( $r ) > 0 ) {
 422                         // The size of the result array is twice the number of fields. (Bug: 65578)
 423                         return count( $r[0] ) / 2;
 424                 } else {
 425                         // If the result is empty return 0
 426                         return 0;
 427                 }
 428         }
 429
 430         /**
 431          * @param ResultWrapper $res
 432          * @param int $n
 433          * @return bool
 434          */
 435         function fieldName( $res, $n ) {
 436                 $r = $res instanceof ResultWrapper ? $res->result : $res;
 437                 if ( is_array( $r ) ) {
 438                         $keys = array_keys( $r[0] );
 439
 440                         return $keys[$n];
 441                 }
 442
 443                 return false;
 444         }
 445
 446         /**
 447          * Use MySQL's naming (accounts for prefix etc) but remove surrounding backticks
 448          *
 449          * @param string $name
 450          * @param string $format
 451          * @return string
 452          */
 453         function tableName( $name, $format = 'quoted' ) {
 454                 // table names starting with sqlite_ are reserved
 455                 if ( strpos( $name, 'sqlite_' ) === 0 ) {
 456                         return $name;
 457                 }
 458
 459                 return str_replace( '"', '', parent::tableName( $name, $format ) );
 460         }
 461
 462         /**
 463          * This must be called after nextSequenceVal
 464          *
 465          * @return int
 466          */
 467         function insertId() {
 468                 // PDO::lastInsertId yields a string :(
 469                 return intval( $this->getBindingHandle()->lastInsertId() );
 470         }
 471
 472         /**
 473          * @param ResultWrapper|array $res
 474          * @param int $row
 475          */
 476         function dataSeek( $res, $row ) {
 477                 if ( $res instanceof ResultWrapper ) {
 478                         $r =& $res->result;
 479                 } else {
 480                         $r =& $res;
 481                 }
 482                 reset( $r );
 483                 if ( $row > 0 ) {
 484                         for ( $i = 0; $i < $row; $i++ ) {
 485                                 next( $r );
 486                         }
 487                 }
 488         }
 489
 490         /**
 491          * @return string
 492          */
 493         function lastError() {
 494                 if ( !is_object( $this->conn ) ) {
 495                         return "Cannot return last error, no db connection";
 496                 }
 497                 $e = $this->conn->errorInfo();
 498
 499                 return isset( $e[2] ) ? $e[2] : '';
 500         }
 501
 502         /**
 503          * @return string
 504          */
 505         function lastErrno() {
 506                 if ( !is_object( $this->conn ) ) {
 507                         return "Cannot return last error, no db connection";
 508                 } else {
 509                         $info = $this->conn->errorInfo();
 510
 511                         return $info[1];
 512                 }
 513         }
 514
 515         /**
 516          * @return int
 517          */
 518         protected function fetchAffectedRowCount() {
 519                 return $this->lastAffectedRowCount;
 520         }
 521
 522         /**
 523          * Returns information about an index
 524          * Returns false if the index does not exist
 525          * - if errors are explicitly ignored, returns NULL on failure
 526          *
 527          * @param string $table
 528          * @param string $index
 529          * @param string $fname
 530          * @return array|false
 531          */
 532         function indexInfo( $table, $index, $fname = __METHOD__ ) {
 533                 $sql = 'PRAGMA index_info(' . $this->addQuotes( $this->indexName( $index ) ) . ')';
 534                 $res = $this->query( $sql, $fname );
 535                 if ( !$res || $res->numRows() == 0 ) {
 536                         return false;
 537                 }
 538                 $info = [];
 539                 foreach ( $res as $row ) {
 540                         $info[] = $row->name;
 541                 }
 542
 543                 return $info;
 544         }
 545
 546         /**
 547          * @param string $table
 548          * @param string $index
 549          * @param string $fname
 550          * @return bool|null
 551          */
 552         function indexUnique( $table, $index, $fname = __METHOD__ ) {
 553                 $row = $this->selectRow( 'sqlite_master', '*',
 554                         [
 555                                 'type' => 'index',
 556                                 'name' => $this->indexName( $index ),
 557                         ], $fname );
 558                 if ( !$row || !isset( $row->sql ) ) {
 559                         return null;
 560                 }
 561
 562                 // $row->sql will be of the form CREATE [UNIQUE] INDEX ...
 563                 $indexPos = strpos( $row->sql, 'INDEX' );
 564                 if ( $indexPos === false ) {
 565                         return null;
 566                 }
 567                 $firstPart = substr( $row->sql, 0, $indexPos );
 568                 $options = explode( ' ', $firstPart );
 569
 570                 return in_array( 'UNIQUE', $options );
 571         }
 572
 573         /**
 574          * Filter the options used in SELECT statements
 575          *
 576          * @param array $options
 577          * @return array
 578          */
 579         function makeSelectOptions( $options ) {
 580                 foreach ( $options as $k => $v ) {
 581                         if ( is_numeric( $k ) && ( $v == 'FOR UPDATE' || $v == 'LOCK IN SHARE MODE' ) ) {
 582                                 $options[$k] = '';
 583                         }
 584                 }
 585
 586                 return parent::makeSelectOptions( $options );
 587         }
 588
 589         /**
 590          * @param array $options
 591          * @return array
 592          */
 593         protected function makeUpdateOptionsArray( $options ) {
 594                 $options = parent::makeUpdateOptionsArray( $options );
 595                 $options = self::fixIgnore( $options );
 596
 597                 return $options;
 598         }
 599
 600         /**
 601          * @param array $options
 602          * @return array
 603          */
 604         static function fixIgnore( $options ) {
 605                 # SQLite uses OR IGNORE not just IGNORE
 606                 foreach ( $options as $k => $v ) {
 607                         if ( $v == 'IGNORE' ) {
 608                                 $options[$k] = 'OR IGNORE';
 609                         }
 610                 }
 611
 612                 return $options;
 613         }
 614
 615         /**
 616          * @param array $options
 617          * @return string
 618          */
 619         function makeInsertOptions( $options ) {
 620                 $options = self::fixIgnore( $options );
 621
 622                 return parent::makeInsertOptions( $options );
 623         }
 624
 625         /**
 626          * Based on generic method (parent) with some prior SQLite-sepcific adjustments
 627          * @param string $table
 628          * @param array $a
 629          * @param string $fname
 630          * @param array $options
 631          * @return bool
 632          */
 633         function insert( $table, $a, $fname = __METHOD__, $options = [] ) {
 634                 if ( !count( $a ) ) {
 635                         return true;
 636                 }
 637
 638                 # SQLite can't handle multi-row inserts, so divide up into multiple single-row inserts
 639                 if ( isset( $a[0] ) && is_array( $a[0] ) ) {
 640                         $ret = true;
 641                         foreach ( $a as $v ) {
 642                                 if ( !parent::insert( $table, $v, "$fname/multi-row", $options ) ) {
 643                                         $ret = false;
 644                                 }
 645                         }
 646                 } else {
 647                         $ret = parent::insert( $table, $a, "$fname/single-row", $options );
 648                 }
 649
 650                 return $ret;
 651         }
 652
 653         /**
 654          * @param string $table
 655          * @param array $uniqueIndexes Unused
 656          * @param string|array $rows
 657          * @param string $fname
 658          * @return bool|ResultWrapper
 659          */
 660         function replace( $table, $uniqueIndexes, $rows, $fname = __METHOD__ ) {
 661                 if ( !count( $rows ) ) {
 662                         return true;
 663                 }
 664
 665                 # SQLite can't handle multi-row replaces, so divide up into multiple single-row queries
 666                 if ( isset( $rows[0] ) && is_array( $rows[0] ) ) {
 667                         $ret = true;
 668                         foreach ( $rows as $v ) {
 669                                 if ( !$this->nativeReplace( $table, $v, "$fname/multi-row" ) ) {
 670                                         $ret = false;
 671                                 }
 672                         }
 673                 } else {
 674                         $ret = $this->nativeReplace( $table, $rows, "$fname/single-row" );
 675                 }
 676
 677                 return $ret;
 678         }
 679
 680         /**
 681          * Returns the size of a text field, or -1 for "unlimited"
 682          * In SQLite this is SQLITE_MAX_LENGTH, by default 1GB. No way to query it though.
 683          *
 684          * @param string $table
 685          * @param string $field
 686          * @return int
 687          */
 688         function textFieldSize( $table, $field ) {
 689                 return -1;
 690         }
 691
 692         /**
 693          * @return bool
 694          */
 695         function unionSupportsOrderAndLimit() {
 696                 return false;
 697         }
 698
 699         /**
 700          * @param string[] $sqls
 701          * @param bool $all Whether to "UNION ALL" or not
 702          * @return string
 703          */
 704         function unionQueries( $sqls, $all ) {
 705                 $glue = $all ? ' UNION ALL ' : ' UNION ';
 706
 707                 return implode( $glue, $sqls );
 708         }
 709
 710         /**
 711          * @return bool
 712          */
 713         function wasDeadlock() {
 714                 return $this->lastErrno() == 5; // SQLITE_BUSY
 715         }
 716
 717         /**
 718          * @return bool
 719          */
 720         function wasReadOnlyError() {
 721                 return $this->lastErrno() == 8; // SQLITE_READONLY;
 722         }
 723
 724         public function wasConnectionError( $errno ) {
 725                 return $errno == 17; // SQLITE_SCHEMA;
 726         }
 727
 728         protected function wasKnownStatementRollbackError() {
 729                 // ON CONFLICT ROLLBACK clauses make it so that SQLITE_CONSTRAINT error is
 730                 // ambiguous with regard to whether it implies a ROLLBACK or an ABORT happened.
 731                 // https://sqlite.org/lang_createtable.html#uniqueconst
 732                 // https://sqlite.org/lang_conflict.html
 733                 return false;
 734         }
 735
 736         /**
 737          * @return string Wikitext of a link to the server software's web site
 738          */
 739         public function getSoftwareLink() {
 740                 return "[{{int:version-db-sqlite-url}} SQLite]";
 741         }
 742
 743         /**
 744          * @return string Version information from the database
 745          */
 746         function getServerVersion() {
 747                 $ver = $this->getBindingHandle()->getAttribute( PDO::ATTR_SERVER_VERSION );
 748
 749                 return $ver;
 750         }
 751
 752         /**
 753          * Get information about a given field
 754          * Returns false if the field does not exist.
 755          *
 756          * @param string $table
 757          * @param string $field
 758          * @return SQLiteField|bool False on failure
 759          */
 760         function fieldInfo( $table, $field ) {
 761                 $tableName = $this->tableName( $table );
 762                 $sql = 'PRAGMA table_info(' . $this->addQuotes( $tableName ) . ')';
 763                 $res = $this->query( $sql, __METHOD__ );
 764                 foreach ( $res as $row ) {
 765                         if ( $row->name == $field ) {
 766                                 return new SQLiteField( $row, $tableName );
 767                         }
 768                 }
 769
 770                 return false;
 771         }
 772
 773         protected function doBegin( $fname = '' ) {
 774                 if ( $this->trxMode ) {
 775                         $this->query( "BEGIN {$this->trxMode}", $fname );
 776                 } else {
 777                         $this->query( 'BEGIN', $fname );
 778                 }
 779                 $this->trxLevel = 1;
 780         }
 781
 782         /**
 783          * @param string $s
 784          * @return string
 785          */
 786         function strencode( $s ) {
 787                 return substr( $this->addQuotes( $s ), 1, -1 );
 788         }
 789
 790         /**
 791          * @param string $b
 792          * @return Blob
 793          */
 794         function encodeBlob( $b ) {
 795                 return new Blob( $b );
 796         }
 797
 798         /**
 799          * @param Blob|string $b
 800          * @return string
 801          */
 802         function decodeBlob( $b ) {
 803                 if ( $b instanceof Blob ) {
 804                         $b = $b->fetch();
 805                 }
 806
 807                 return $b;
 808         }
 809
 810         /**
 811          * @param string|int|null|bool|Blob $s
 812          * @return string|int
 813          */
 814         function addQuotes( $s ) {
 815                 if ( $s instanceof Blob ) {
 816                         return "x'" . bin2hex( $s->fetch() ) . "'";
 817                 } elseif ( is_bool( $s ) ) {
 818                         return (int)$s;
 819                 } elseif ( strpos( (string)$s, "\0" ) !== false ) {
 820                         // SQLite doesn't support \0 in strings, so use the hex representation as a workaround.
 821                         // This is a known limitation of SQLite's mprintf function which PDO
 822                         // should work around, but doesn't. I have reported this to php.net as bug #63419:
 823                         // https://bugs.php.net/bug.php?id=63419
 824                         // There was already a similar report for SQLite3::escapeString, bug #62361:
 825                         // https://bugs.php.net/bug.php?id=62361
 826                         // There is an additional bug regarding sorting this data after insert
 827                         // on older versions of sqlite shipped with ubuntu 12.04
 828                         // https://phabricator.wikimedia.org/T74367
 829                         $this->queryLogger->debug(
 830                                 __FUNCTION__ .
 831                                 ': Quoting value containing null byte. ' .
 832                                 'For consistency all binary data should have been ' .
 833                                 'first processed with self::encodeBlob()'
 834                         );
 835                         return "x'" . bin2hex( (string)$s ) . "'";
 836                 } else {
 837                         return $this->getBindingHandle()->quote( (string)$s );
 838                 }
 839         }
 840
 841         public function buildSubstring( $input, $startPosition, $length = null ) {
 842                 $this->assertBuildSubstringParams( $startPosition, $length );
 843                 $params = [ $input, $startPosition ];
 844                 if ( $length !== null ) {
 845                         $params[] = $length;
 846                 }
 847                 return 'SUBSTR(' . implode( ',', $params ) . ')';
 848         }
 849
 850         /**
 851          * @param string $field Field or column to cast
 852          * @return string
 853          * @since 1.28
 854          */
 855         public function buildStringCast( $field ) {
 856                 return 'CAST ( ' . $field . ' AS TEXT )';
 857         }
 858
 859         /**
 860          * No-op version of deadlockLoop
 861          *
 862          * @return mixed
 863          */
 864         public function deadlockLoop( /*...*/ ) {
 865                 $args = func_get_args();
 866                 $function = array_shift( $args );
 867
 868                 return call_user_func_array( $function, $args );
 869         }
 870
 871         /**
 872          * @param string $s
 873          * @return string
 874          */
 875         protected function replaceVars( $s ) {
 876                 $s = parent::replaceVars( $s );
 877                 if ( preg_match( '/^\s*(CREATE|ALTER) TABLE/i', $s ) ) {
 878                         // CREATE TABLE hacks to allow schema file sharing with MySQL
 879
 880                         // binary/varbinary column type -> blob
 881                         $s = preg_replace( '/\b(var)?binary(\(\d+\))/i', 'BLOB', $s );
 882                         // no such thing as unsigned
 883                         $s = preg_replace( '/\b(un)?signed\b/i', '', $s );
 884                         // INT -> INTEGER
 885                         $s = preg_replace( '/\b(tiny|small|medium|big|)int(\s*\(\s*\d+\s*\)|\b)/i', 'INTEGER', $s );
 886                         // floating point types -> REAL
 887                         $s = preg_replace(
 888                                 '/\b(float|double(\s+precision)?)(\s*\(\s*\d+\s*(,\s*\d+\s*)?\)|\b)/i',
 889                                 'REAL',
 890                                 $s
 891                         );
 892                         // varchar -> TEXT
 893                         $s = preg_replace( '/\b(var)?char\s*\(.*?\)/i', 'TEXT', $s );
 894                         // TEXT normalization
 895                         $s = preg_replace( '/\b(tiny|medium|long)text\b/i', 'TEXT', $s );
 896                         // BLOB normalization
 897                         $s = preg_replace( '/\b(tiny|small|medium|long|)blob\b/i', 'BLOB', $s );
 898                         // BOOL -> INTEGER
 899                         $s = preg_replace( '/\bbool(ean)?\b/i', 'INTEGER', $s );
 900                         // DATETIME -> TEXT
 901                         $s = preg_replace( '/\b(datetime|timestamp)\b/i', 'TEXT', $s );
 902                         // No ENUM type
 903                         $s = preg_replace( '/\benum\s*\([^)]*\)/i', 'TEXT', $s );
 904                         // binary collation type -> nothing
 905                         $s = preg_replace( '/\bbinary\b/i', '', $s );
 906                         // auto_increment -> autoincrement
 907                         $s = preg_replace( '/\bauto_increment\b/i', 'AUTOINCREMENT', $s );
 908                         // No explicit options
 909                         $s = preg_replace( '/\)[^);]*(;?)\s*$/', ')\1', $s );
 910                         // AUTOINCREMENT should immedidately follow PRIMARY KEY
 911                         $s = preg_replace( '/primary key (.*?) autoincrement/i', 'PRIMARY KEY AUTOINCREMENT $1', $s );
 912                 } elseif ( preg_match( '/^\s*CREATE (\s*(?:UNIQUE|FULLTEXT)\s+)?INDEX/i', $s ) ) {
 913                         // No truncated indexes
 914                         $s = preg_replace( '/\(\d+\)/', '', $s );
 915                         // No FULLTEXT
 916                         $s = preg_replace( '/\bfulltext\b/i', '', $s );
 917                 } elseif ( preg_match( '/^\s*DROP INDEX/i', $s ) ) {
 918                         // DROP INDEX is database-wide, not table-specific, so no ON <table> clause.
 919                         $s = preg_replace( '/\sON\s+[^\s]*/i', '', $s );
 920                 } elseif ( preg_match( '/^\s*INSERT IGNORE\b/i', $s ) ) {
 921                         // INSERT IGNORE --> INSERT OR IGNORE
 922                         $s = preg_replace( '/^\s*INSERT IGNORE\b/i', 'INSERT OR IGNORE', $s );
 923                 }
 924
 925                 return $s;
 926         }
 927
 928         public function lock( $lockName, $method, $timeout = 5 ) {
 929                 if ( !is_dir( "{$this->dbDir}/locks" ) ) { // create dir as needed
 930                         if ( !is_writable( $this->dbDir ) || !mkdir( "{$this->dbDir}/locks" ) ) {
 931                                 throw new DBError( $this, "Cannot create directory \"{$this->dbDir}/locks\"." );
 932                         }
 933                 }
 934
 935                 return $this->lockMgr->lock( [ $lockName ], LockManager::LOCK_EX, $timeout )->isOK();
 936         }
 937
 938         public function unlock( $lockName, $method ) {
 939                 return $this->lockMgr->unlock( [ $lockName ], LockManager::LOCK_EX )->isOK();
 940         }
 941
 942         /**
 943          * Build a concatenation list to feed into a SQL query
 944          *
 945          * @param string[] $stringList
 946          * @return string
 947          */
 948         function buildConcat( $stringList ) {
 949                 return '(' . implode( ') || (', $stringList ) . ')';
 950         }
 951
 952         public function buildGroupConcatField(
 953                 $delim, $table, $field, $conds = '', $join_conds = []
 954         ) {
 955                 $fld = "group_concat($field," . $this->addQuotes( $delim ) . ')';
 956
 957                 return '(' . $this->selectSQLText( $table, $fld, $conds, null, [], $join_conds ) . ')';
 958         }
 959
 960         /**
 961          * @param string $oldName
 962          * @param string $newName
 963          * @param bool $temporary
 964          * @param string $fname
 965          * @return bool|ResultWrapper
 966          * @throws RuntimeException
 967          */
 968         function duplicateTableStructure( $oldName, $newName, $temporary = false, $fname = __METHOD__ ) {
 969                 $res = $this->query( "SELECT sql FROM sqlite_master WHERE tbl_name=" .
 970                         $this->addQuotes( $oldName ) . " AND type='table'", $fname );
 971                 $obj = $this->fetchObject( $res );
 972                 if ( !$obj ) {
 973                         throw new RuntimeException( "Couldn't retrieve structure for table $oldName" );
 974                 }
 975                 $sql = $obj->sql;
 976                 $sql = preg_replace(
 977                         '/(?<=\W)"?' . preg_quote( trim( $this->addIdentifierQuotes( $oldName ), '"' ) ) . '"?(?=\W)/',
 978                         $this->addIdentifierQuotes( $newName ),
 979                         $sql,
 980                         1
 981                 );
 982                 if ( $temporary ) {
 983                         if ( preg_match( '/^\\s*CREATE\\s+VIRTUAL\\s+TABLE\b/i', $sql ) ) {
 984                                 $this->queryLogger->debug(
 985                                         "Table $oldName is virtual, can't create a temporary duplicate.\n" );
 986                         } else {
 987                                 $sql = str_replace( 'CREATE TABLE', 'CREATE TEMPORARY TABLE', $sql );
 988                         }
 989                 }
 990
 991                 $res = $this->query( $sql, $fname );
 992
 993                 // Take over indexes
 994                 $indexList = $this->query( 'PRAGMA INDEX_LIST(' . $this->addQuotes( $oldName ) . ')' );
 995                 foreach ( $indexList as $index ) {
 996                         if ( strpos( $index->name, 'sqlite_autoindex' ) === 0 ) {
 997                                 continue;
 998                         }
 999
1000                         if ( $index->unique ) {
1001                                 $sql = 'CREATE UNIQUE INDEX';
1002                         } else {
1003                                 $sql = 'CREATE INDEX';
1004                         }
1005                         // Try to come up with a new index name, given indexes have database scope in SQLite
1006                         $indexName = $newName . '_' . $index->name;
1007                         $sql .= ' ' . $indexName . ' ON ' . $newName;
1008
1009                         $indexInfo = $this->query( 'PRAGMA INDEX_INFO(' . $this->addQuotes( $index->name ) . ')' );
1010                         $fields = [];
1011                         foreach ( $indexInfo as $indexInfoRow ) {
1012                                 $fields[$indexInfoRow->seqno] = $indexInfoRow->name;
1013                         }
1014
1015                         $sql .= '(' . implode( ',', $fields ) . ')';
1016
1017                         $this->query( $sql );
1018                 }
1019
1020                 return $res;
1021         }
1022
1023         /**
1024          * List all tables on the database
1025          *
1026          * @param string $prefix Only show tables with this prefix, e.g. mw_
1027          * @param string $fname Calling function name
1028          *
1029          * @return array
1030          */
1031         function listTables( $prefix = null, $fname = __METHOD__ ) {
1032                 $result = $this->select(
1033                         'sqlite_master',
1034                         'name',
1035                         "type='table'"
1036                 );
1037
1038                 $endArray = [];
1039
1040                 foreach ( $result as $table ) {
1041                         $vars = get_object_vars( $table );
1042                         $table = array_pop( $vars );
1043
1044                         if ( !$prefix || strpos( $table, $prefix ) === 0 ) {
1045                                 if ( strpos( $table, 'sqlite_' ) !== 0 ) {
1046                                         $endArray[] = $table;
1047                                 }
1048                         }
1049                 }
1050
1051                 return $endArray;
1052         }
1053
1054         /**
1055          * Override due to no CASCADE support
1056          *
1057          * @param string $tableName
1058          * @param string $fName
1059          * @return bool|ResultWrapper
1060          * @throws DBReadOnlyError
1061          */
1062         public function dropTable( $tableName, $fName = __METHOD__ ) {
1063                 if ( !$this->tableExists( $tableName, $fName ) ) {
1064                         return false;
1065                 }
1066                 $sql = "DROP TABLE " . $this->tableName( $tableName );
1067
1068                 return $this->query( $sql, $fName );
1069         }
1070
1071         public function setTableAliases( array $aliases ) {
1072                 parent::setTableAliases( $aliases );
1073                 foreach ( $this->tableAliases as $params ) {
1074                         if ( isset( $this->alreadyAttached[$params['dbname']] ) ) {
1075                                 continue;
1076                         }
1077                         $this->attachDatabase( $params['dbname'] );
1078                         $this->alreadyAttached[$params['dbname']] = true;
1079                 }
1080         }
1081
1082         public function resetSequenceForTable( $table, $fname = __METHOD__ ) {
1083                 $encTable = $this->addIdentifierQuotes( 'sqlite_sequence' );
1084                 $encName = $this->addQuotes( $this->tableName( $table, 'raw' ) );
1085                 $this->query( "DELETE FROM $encTable WHERE name = $encName", $fname );
1086         }
1087
1088         public function databasesAreIndependent() {
1089                 return true;
1090         }
1091
1092         /**
1093          * @return string
1094          */
1095         public function __toString() {
1096                 return is_object( $this->conn )
1097                         ? 'SQLite ' . (string)$this->conn->getAttribute( PDO::ATTR_SERVER_VERSION )
1098                         : '(not connected)';
1099         }
1100
1101         /**
1102          * @return PDO
1103          */
1104         protected function getBindingHandle() {
1105                 return parent::getBindingHandle();
1106         }
1107 }
1108
1109 class_alias( DatabaseSqlite::class, 'DatabaseSqlite' );