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         /**
 224          * @return string SQLite DB file path
 225          * @since 1.25
 226          */
 227         public function getDbFilePath() {
 228                 return $this->dbPath;
 229         }
 230
 231         /**
 232          * Does not actually close the connection, just destroys the reference for GC to do its work
 233          * @return bool
 234          */
 235         protected function closeConnection() {
 236                 $this->conn = null;
 237
 238                 return true;
 239         }
 240
 241         /**
 242          * Generates a database file name. Explicitly public for installer.
 243          * @param string $dir Directory where database resides
 244          * @param string $dbName Database name
 245          * @return string
 246          */
 247         public static function generateFileName( $dir, $dbName ) {
 248                 return "$dir/$dbName.sqlite";
 249         }
 250
 251         /**
 252          * Check if the searchindext table is FTS enabled.
 253          * @return bool False if not enabled.
 254          */
 255         function checkForEnabledSearch() {
 256                 if ( self::$fulltextEnabled === null ) {
 257                         self::$fulltextEnabled = false;
 258                         $table = $this->tableName( 'searchindex' );
 259                         $res = $this->query( "SELECT sql FROM sqlite_master WHERE tbl_name = '$table'", __METHOD__ );
 260                         if ( $res ) {
 261                                 $row = $res->fetchRow();
 262                                 self::$fulltextEnabled = stristr( $row['sql'], 'fts' ) !== false;
 263                         }
 264                 }
 265
 266                 return self::$fulltextEnabled;
 267         }
 268
 269         /**
 270          * Returns version of currently supported SQLite fulltext search module or false if none present.
 271          * @return string
 272          */
 273         static function getFulltextSearchModule() {
 274                 static $cachedResult = null;
 275                 if ( $cachedResult !== null ) {
 276                         return $cachedResult;
 277                 }
 278                 $cachedResult = false;
 279                 $table = 'dummy_search_test';
 280
 281                 $db = self::newStandaloneInstance( ':memory:' );
 282                 if ( $db->query( "CREATE VIRTUAL TABLE $table USING FTS3(dummy_field)", __METHOD__, true ) ) {
 283                         $cachedResult = 'FTS3';
 284                 }
 285                 $db->close();
 286
 287                 return $cachedResult;
 288         }
 289
 290         /**
 291          * Attaches external database to our connection, see https://sqlite.org/lang_attach.html
 292          * for details.
 293          *
 294          * @param string $name Database name to be used in queries like
 295          *   SELECT foo FROM dbname.table
 296          * @param bool|string $file Database file name. If omitted, will be generated
 297          *   using $name and configured data directory
 298          * @param string $fname Calling function name
 299          * @return ResultWrapper
 300          */
 301         function attachDatabase( $name, $file = false, $fname = __METHOD__ ) {
 302                 if ( !$file ) {
 303                         $file = self::generateFileName( $this->dbDir, $name );
 304                 }
 305                 $file = $this->addQuotes( $file );
 306
 307                 return $this->query( "ATTACH DATABASE $file AS $name", $fname );
 308         }
 309
 310         function isWriteQuery( $sql ) {
 311                 return parent::isWriteQuery( $sql ) && !preg_match( '/^(ATTACH|PRAGMA)\b/i', $sql );
 312         }
 313
 314         protected function isTransactableQuery( $sql ) {
 315                 return parent::isTransactableQuery( $sql ) && !in_array(
 316                         $this->getQueryVerb( $sql ),
 317                         [ 'ATTACH', 'PRAGMA' ],
 318                         true
 319                 );
 320         }
 321
 322         /**
 323          * SQLite doesn't allow buffered results or data seeking etc, so we'll use fetchAll as the result
 324          *
 325          * @param string $sql
 326          * @return bool|ResultWrapper
 327          */
 328         protected function doQuery( $sql ) {
 329                 $res = $this->getBindingHandle()->query( $sql );
 330                 if ( $res === false ) {
 331                         return false;
 332                 }
 333
 334                 $r = $res instanceof ResultWrapper ? $res->result : $res;
 335                 $this->lastAffectedRowCount = $r->rowCount();
 336                 $res = new ResultWrapper( $this, $r->fetchAll() );
 337
 338                 return $res;
 339         }
 340
 341         /**
 342          * @param ResultWrapper|mixed $res
 343          */
 344         function freeResult( $res ) {
 345                 if ( $res instanceof ResultWrapper ) {
 346                         $res->result = null;
 347                 } else {
 348                         $res = null;
 349                 }
 350         }
 351
 352         /**
 353          * @param ResultWrapper|array $res
 354          * @return stdClass|bool
 355          */
 356         function fetchObject( $res ) {
 357                 if ( $res instanceof ResultWrapper ) {
 358                         $r =& $res->result;
 359                 } else {
 360                         $r =& $res;
 361                 }
 362
 363                 $cur = current( $r );
 364                 if ( is_array( $cur ) ) {
 365                         next( $r );
 366                         $obj = new stdClass;
 367                         foreach ( $cur as $k => $v ) {
 368                                 if ( !is_numeric( $k ) ) {
 369                                         $obj->$k = $v;
 370                                 }
 371                         }
 372
 373                         return $obj;
 374                 }
 375
 376                 return false;
 377         }
 378
 379         /**
 380          * @param ResultWrapper|mixed $res
 381          * @return array|bool
 382          */
 383         function fetchRow( $res ) {
 384                 if ( $res instanceof ResultWrapper ) {
 385                         $r =& $res->result;
 386                 } else {
 387                         $r =& $res;
 388                 }
 389                 $cur = current( $r );
 390                 if ( is_array( $cur ) ) {
 391                         next( $r );
 392
 393                         return $cur;
 394                 }
 395
 396                 return false;
 397         }
 398
 399         /**
 400          * The PDO::Statement class implements the array interface so count() will work
 401          *
 402          * @param ResultWrapper|array $res
 403          * @return int
 404          */
 405         function numRows( $res ) {
 406                 $r = $res instanceof ResultWrapper ? $res->result : $res;
 407
 408                 return count( $r );
 409         }
 410
 411         /**
 412          * @param ResultWrapper $res
 413          * @return int
 414          */
 415         function numFields( $res ) {
 416                 $r = $res instanceof ResultWrapper ? $res->result : $res;
 417                 if ( is_array( $r ) && count( $r ) > 0 ) {
 418                         // The size of the result array is twice the number of fields. (Bug: 65578)
 419                         return count( $r[0] ) / 2;
 420                 } else {
 421                         // If the result is empty return 0
 422                         return 0;
 423                 }
 424         }
 425
 426         /**
 427          * @param ResultWrapper $res
 428          * @param int $n
 429          * @return bool
 430          */
 431         function fieldName( $res, $n ) {
 432                 $r = $res instanceof ResultWrapper ? $res->result : $res;
 433                 if ( is_array( $r ) ) {
 434                         $keys = array_keys( $r[0] );
 435
 436                         return $keys[$n];
 437                 }
 438
 439                 return false;
 440         }
 441
 442         /**
 443          * Use MySQL's naming (accounts for prefix etc) but remove surrounding backticks
 444          *
 445          * @param string $name
 446          * @param string $format
 447          * @return string
 448          */
 449         function tableName( $name, $format = 'quoted' ) {
 450                 // table names starting with sqlite_ are reserved
 451                 if ( strpos( $name, 'sqlite_' ) === 0 ) {
 452                         return $name;
 453                 }
 454
 455                 return str_replace( '"', '', parent::tableName( $name, $format ) );
 456         }
 457
 458         /**
 459          * This must be called after nextSequenceVal
 460          *
 461          * @return int
 462          */
 463         function insertId() {
 464                 // PDO::lastInsertId yields a string :(
 465                 return intval( $this->getBindingHandle()->lastInsertId() );
 466         }
 467
 468         /**
 469          * @param ResultWrapper|array $res
 470          * @param int $row
 471          */
 472         function dataSeek( $res, $row ) {
 473                 if ( $res instanceof ResultWrapper ) {
 474                         $r =& $res->result;
 475                 } else {
 476                         $r =& $res;
 477                 }
 478                 reset( $r );
 479                 if ( $row > 0 ) {
 480                         for ( $i = 0; $i < $row; $i++ ) {
 481                                 next( $r );
 482                         }
 483                 }
 484         }
 485
 486         /**
 487          * @return string
 488          */
 489         function lastError() {
 490                 if ( !is_object( $this->conn ) ) {
 491                         return "Cannot return last error, no db connection";
 492                 }
 493                 $e = $this->conn->errorInfo();
 494
 495                 return isset( $e[2] ) ? $e[2] : '';
 496         }
 497
 498         /**
 499          * @return string
 500          */
 501         function lastErrno() {
 502                 if ( !is_object( $this->conn ) ) {
 503                         return "Cannot return last error, no db connection";
 504                 } else {
 505                         $info = $this->conn->errorInfo();
 506
 507                         return $info[1];
 508                 }
 509         }
 510
 511         /**
 512          * @return int
 513          */
 514         protected function fetchAffectedRowCount() {
 515                 return $this->lastAffectedRowCount;
 516         }
 517
 518         /**
 519          * Returns information about an index
 520          * Returns false if the index does not exist
 521          * - if errors are explicitly ignored, returns NULL on failure
 522          *
 523          * @param string $table
 524          * @param string $index
 525          * @param string $fname
 526          * @return array|false
 527          */
 528         function indexInfo( $table, $index, $fname = __METHOD__ ) {
 529                 $sql = 'PRAGMA index_info(' . $this->addQuotes( $this->indexName( $index ) ) . ')';
 530                 $res = $this->query( $sql, $fname );
 531                 if ( !$res || $res->numRows() == 0 ) {
 532                         return false;
 533                 }
 534                 $info = [];
 535                 foreach ( $res as $row ) {
 536                         $info[] = $row->name;
 537                 }
 538
 539                 return $info;
 540         }
 541
 542         /**
 543          * @param string $table
 544          * @param string $index
 545          * @param string $fname
 546          * @return bool|null
 547          */
 548         function indexUnique( $table, $index, $fname = __METHOD__ ) {
 549                 $row = $this->selectRow( 'sqlite_master', '*',
 550                         [
 551                                 'type' => 'index',
 552                                 'name' => $this->indexName( $index ),
 553                         ], $fname );
 554                 if ( !$row || !isset( $row->sql ) ) {
 555                         return null;
 556                 }
 557
 558                 // $row->sql will be of the form CREATE [UNIQUE] INDEX ...
 559                 $indexPos = strpos( $row->sql, 'INDEX' );
 560                 if ( $indexPos === false ) {
 561                         return null;
 562                 }
 563                 $firstPart = substr( $row->sql, 0, $indexPos );
 564                 $options = explode( ' ', $firstPart );
 565
 566                 return in_array( 'UNIQUE', $options );
 567         }
 568
 569         /**
 570          * Filter the options used in SELECT statements
 571          *
 572          * @param array $options
 573          * @return array
 574          */
 575         function makeSelectOptions( $options ) {
 576                 foreach ( $options as $k => $v ) {
 577                         if ( is_numeric( $k ) && ( $v == 'FOR UPDATE' || $v == 'LOCK IN SHARE MODE' ) ) {
 578                                 $options[$k] = '';
 579                         }
 580                 }
 581
 582                 return parent::makeSelectOptions( $options );
 583         }
 584
 585         /**
 586          * @param array $options
 587          * @return array
 588          */
 589         protected function makeUpdateOptionsArray( $options ) {
 590                 $options = parent::makeUpdateOptionsArray( $options );
 591                 $options = self::fixIgnore( $options );
 592
 593                 return $options;
 594         }
 595
 596         /**
 597          * @param array $options
 598          * @return array
 599          */
 600         static function fixIgnore( $options ) {
 601                 # SQLite uses OR IGNORE not just IGNORE
 602                 foreach ( $options as $k => $v ) {
 603                         if ( $v == 'IGNORE' ) {
 604                                 $options[$k] = 'OR IGNORE';
 605                         }
 606                 }
 607
 608                 return $options;
 609         }
 610
 611         /**
 612          * @param array $options
 613          * @return string
 614          */
 615         function makeInsertOptions( $options ) {
 616                 $options = self::fixIgnore( $options );
 617
 618                 return parent::makeInsertOptions( $options );
 619         }
 620
 621         /**
 622          * Based on generic method (parent) with some prior SQLite-sepcific adjustments
 623          * @param string $table
 624          * @param array $a
 625          * @param string $fname
 626          * @param array $options
 627          * @return bool
 628          */
 629         function insert( $table, $a, $fname = __METHOD__, $options = [] ) {
 630                 if ( !count( $a ) ) {
 631                         return true;
 632                 }
 633
 634                 # SQLite can't handle multi-row inserts, so divide up into multiple single-row inserts
 635                 if ( isset( $a[0] ) && is_array( $a[0] ) ) {
 636                         $ret = true;
 637                         foreach ( $a as $v ) {
 638                                 if ( !parent::insert( $table, $v, "$fname/multi-row", $options ) ) {
 639                                         $ret = false;
 640                                 }
 641                         }
 642                 } else {
 643                         $ret = parent::insert( $table, $a, "$fname/single-row", $options );
 644                 }
 645
 646                 return $ret;
 647         }
 648
 649         /**
 650          * @param string $table
 651          * @param array $uniqueIndexes Unused
 652          * @param string|array $rows
 653          * @param string $fname
 654          * @return bool|ResultWrapper
 655          */
 656         function replace( $table, $uniqueIndexes, $rows, $fname = __METHOD__ ) {
 657                 if ( !count( $rows ) ) {
 658                         return true;
 659                 }
 660
 661                 # SQLite can't handle multi-row replaces, so divide up into multiple single-row queries
 662                 if ( isset( $rows[0] ) && is_array( $rows[0] ) ) {
 663                         $ret = true;
 664                         foreach ( $rows as $v ) {
 665                                 if ( !$this->nativeReplace( $table, $v, "$fname/multi-row" ) ) {
 666                                         $ret = false;
 667                                 }
 668                         }
 669                 } else {
 670                         $ret = $this->nativeReplace( $table, $rows, "$fname/single-row" );
 671                 }
 672
 673                 return $ret;
 674         }
 675
 676         /**
 677          * Returns the size of a text field, or -1 for "unlimited"
 678          * In SQLite this is SQLITE_MAX_LENGTH, by default 1GB. No way to query it though.
 679          *
 680          * @param string $table
 681          * @param string $field
 682          * @return int
 683          */
 684         function textFieldSize( $table, $field ) {
 685                 return -1;
 686         }
 687
 688         /**
 689          * @return bool
 690          */
 691         function unionSupportsOrderAndLimit() {
 692                 return false;
 693         }
 694
 695         /**
 696          * @param string[] $sqls
 697          * @param bool $all Whether to "UNION ALL" or not
 698          * @return string
 699          */
 700         function unionQueries( $sqls, $all ) {
 701                 $glue = $all ? ' UNION ALL ' : ' UNION ';
 702
 703                 return implode( $glue, $sqls );
 704         }
 705
 706         /**
 707          * @return bool
 708          */
 709         function wasDeadlock() {
 710                 return $this->lastErrno() == 5; // SQLITE_BUSY
 711         }
 712
 713         /**
 714          * @return bool
 715          */
 716         function wasReadOnlyError() {
 717                 return $this->lastErrno() == 8; // SQLITE_READONLY;
 718         }
 719
 720         public function wasConnectionError( $errno ) {
 721                 return $errno == 17; // SQLITE_SCHEMA;
 722         }
 723
 724         protected function wasKnownStatementRollbackError() {
 725                 // ON CONFLICT ROLLBACK clauses make it so that SQLITE_CONSTRAINT error is
 726                 // ambiguous with regard to whether it implies a ROLLBACK or an ABORT happened.
 727                 // https://sqlite.org/lang_createtable.html#uniqueconst
 728                 // https://sqlite.org/lang_conflict.html
 729                 return false;
 730         }
 731
 732         /**
 733          * @return string Wikitext of a link to the server software's web site
 734          */
 735         public function getSoftwareLink() {
 736                 return "[{{int:version-db-sqlite-url}} SQLite]";
 737         }
 738
 739         /**
 740          * @return string Version information from the database
 741          */
 742         function getServerVersion() {
 743                 $ver = $this->getBindingHandle()->getAttribute( PDO::ATTR_SERVER_VERSION );
 744
 745                 return $ver;
 746         }
 747
 748         /**
 749          * Get information about a given field
 750          * Returns false if the field does not exist.
 751          *
 752          * @param string $table
 753          * @param string $field
 754          * @return SQLiteField|bool False on failure
 755          */
 756         function fieldInfo( $table, $field ) {
 757                 $tableName = $this->tableName( $table );
 758                 $sql = 'PRAGMA table_info(' . $this->addQuotes( $tableName ) . ')';
 759                 $res = $this->query( $sql, __METHOD__ );
 760                 foreach ( $res as $row ) {
 761                         if ( $row->name == $field ) {
 762                                 return new SQLiteField( $row, $tableName );
 763                         }
 764                 }
 765
 766                 return false;
 767         }
 768
 769         protected function doBegin( $fname = '' ) {
 770                 if ( $this->trxMode ) {
 771                         $this->query( "BEGIN {$this->trxMode}", $fname );
 772                 } else {
 773                         $this->query( 'BEGIN', $fname );
 774                 }
 775                 $this->trxLevel = 1;
 776         }
 777
 778         /**
 779          * @param string $s
 780          * @return string
 781          */
 782         function strencode( $s ) {
 783                 return substr( $this->addQuotes( $s ), 1, -1 );
 784         }
 785
 786         /**
 787          * @param string $b
 788          * @return Blob
 789          */
 790         function encodeBlob( $b ) {
 791                 return new Blob( $b );
 792         }
 793
 794         /**
 795          * @param Blob|string $b
 796          * @return string
 797          */
 798         function decodeBlob( $b ) {
 799                 if ( $b instanceof Blob ) {
 800                         $b = $b->fetch();
 801                 }
 802
 803                 return $b;
 804         }
 805
 806         /**
 807          * @param string|int|null|bool|Blob $s
 808          * @return string|int
 809          */
 810         function addQuotes( $s ) {
 811                 if ( $s instanceof Blob ) {
 812                         return "x'" . bin2hex( $s->fetch() ) . "'";
 813                 } elseif ( is_bool( $s ) ) {
 814                         return (int)$s;
 815                 } elseif ( strpos( (string)$s, "\0" ) !== false ) {
 816                         // SQLite doesn't support \0 in strings, so use the hex representation as a workaround.
 817                         // This is a known limitation of SQLite's mprintf function which PDO
 818                         // should work around, but doesn't. I have reported this to php.net as bug #63419:
 819                         // https://bugs.php.net/bug.php?id=63419
 820                         // There was already a similar report for SQLite3::escapeString, bug #62361:
 821                         // https://bugs.php.net/bug.php?id=62361
 822                         // There is an additional bug regarding sorting this data after insert
 823                         // on older versions of sqlite shipped with ubuntu 12.04
 824                         // https://phabricator.wikimedia.org/T74367
 825                         $this->queryLogger->debug(
 826                                 __FUNCTION__ .
 827                                 ': Quoting value containing null byte. ' .
 828                                 'For consistency all binary data should have been ' .
 829                                 'first processed with self::encodeBlob()'
 830                         );
 831                         return "x'" . bin2hex( (string)$s ) . "'";
 832                 } else {
 833                         return $this->getBindingHandle()->quote( (string)$s );
 834                 }
 835         }
 836
 837         public function buildSubstring( $input, $startPosition, $length = null ) {
 838                 $this->assertBuildSubstringParams( $startPosition, $length );
 839                 $params = [ $input, $startPosition ];
 840                 if ( $length !== null ) {
 841                         $params[] = $length;
 842                 }
 843                 return 'SUBSTR(' . implode( ',', $params ) . ')';
 844         }
 845
 846         /**
 847          * @param string $field Field or column to cast
 848          * @return string
 849          * @since 1.28
 850          */
 851         public function buildStringCast( $field ) {
 852                 return 'CAST ( ' . $field . ' AS TEXT )';
 853         }
 854
 855         /**
 856          * No-op version of deadlockLoop
 857          *
 858          * @return mixed
 859          */
 860         public function deadlockLoop( /*...*/ ) {
 861                 $args = func_get_args();
 862                 $function = array_shift( $args );
 863
 864                 return call_user_func_array( $function, $args );
 865         }
 866
 867         /**
 868          * @param string $s
 869          * @return string
 870          */
 871         protected function replaceVars( $s ) {
 872                 $s = parent::replaceVars( $s );
 873                 if ( preg_match( '/^\s*(CREATE|ALTER) TABLE/i', $s ) ) {
 874                         // CREATE TABLE hacks to allow schema file sharing with MySQL
 875
 876                         // binary/varbinary column type -> blob
 877                         $s = preg_replace( '/\b(var)?binary(\(\d+\))/i', 'BLOB', $s );
 878                         // no such thing as unsigned
 879                         $s = preg_replace( '/\b(un)?signed\b/i', '', $s );
 880                         // INT -> INTEGER
 881                         $s = preg_replace( '/\b(tiny|small|medium|big|)int(\s*\(\s*\d+\s*\)|\b)/i', 'INTEGER', $s );
 882                         // floating point types -> REAL
 883                         $s = preg_replace(
 884                                 '/\b(float|double(\s+precision)?)(\s*\(\s*\d+\s*(,\s*\d+\s*)?\)|\b)/i',
 885                                 'REAL',
 886                                 $s
 887                         );
 888                         // varchar -> TEXT
 889                         $s = preg_replace( '/\b(var)?char\s*\(.*?\)/i', 'TEXT', $s );
 890                         // TEXT normalization
 891                         $s = preg_replace( '/\b(tiny|medium|long)text\b/i', 'TEXT', $s );
 892                         // BLOB normalization
 893                         $s = preg_replace( '/\b(tiny|small|medium|long|)blob\b/i', 'BLOB', $s );
 894                         // BOOL -> INTEGER
 895                         $s = preg_replace( '/\bbool(ean)?\b/i', 'INTEGER', $s );
 896                         // DATETIME -> TEXT
 897                         $s = preg_replace( '/\b(datetime|timestamp)\b/i', 'TEXT', $s );
 898                         // No ENUM type
 899                         $s = preg_replace( '/\benum\s*\([^)]*\)/i', 'TEXT', $s );
 900                         // binary collation type -> nothing
 901                         $s = preg_replace( '/\bbinary\b/i', '', $s );
 902                         // auto_increment -> autoincrement
 903                         $s = preg_replace( '/\bauto_increment\b/i', 'AUTOINCREMENT', $s );
 904                         // No explicit options
 905                         $s = preg_replace( '/\)[^);]*(;?)\s*$/', ')\1', $s );
 906                         // AUTOINCREMENT should immedidately follow PRIMARY KEY
 907                         $s = preg_replace( '/primary key (.*?) autoincrement/i', 'PRIMARY KEY AUTOINCREMENT $1', $s );
 908                 } elseif ( preg_match( '/^\s*CREATE (\s*(?:UNIQUE|FULLTEXT)\s+)?INDEX/i', $s ) ) {
 909                         // No truncated indexes
 910                         $s = preg_replace( '/\(\d+\)/', '', $s );
 911                         // No FULLTEXT
 912                         $s = preg_replace( '/\bfulltext\b/i', '', $s );
 913                 } elseif ( preg_match( '/^\s*DROP INDEX/i', $s ) ) {
 914                         // DROP INDEX is database-wide, not table-specific, so no ON <table> clause.
 915                         $s = preg_replace( '/\sON\s+[^\s]*/i', '', $s );
 916                 } elseif ( preg_match( '/^\s*INSERT IGNORE\b/i', $s ) ) {
 917                         // INSERT IGNORE --> INSERT OR IGNORE
 918                         $s = preg_replace( '/^\s*INSERT IGNORE\b/i', 'INSERT OR IGNORE', $s );
 919                 }
 920
 921                 return $s;
 922         }
 923
 924         public function lock( $lockName, $method, $timeout = 5 ) {
 925                 if ( !is_dir( "{$this->dbDir}/locks" ) ) { // create dir as needed
 926                         if ( !is_writable( $this->dbDir ) || !mkdir( "{$this->dbDir}/locks" ) ) {
 927                                 throw new DBError( $this, "Cannot create directory \"{$this->dbDir}/locks\"." );
 928                         }
 929                 }
 930
 931                 return $this->lockMgr->lock( [ $lockName ], LockManager::LOCK_EX, $timeout )->isOK();
 932         }
 933
 934         public function unlock( $lockName, $method ) {
 935                 return $this->lockMgr->unlock( [ $lockName ], LockManager::LOCK_EX )->isOK();
 936         }
 937
 938         /**
 939          * Build a concatenation list to feed into a SQL query
 940          *
 941          * @param string[] $stringList
 942          * @return string
 943          */
 944         function buildConcat( $stringList ) {
 945                 return '(' . implode( ') || (', $stringList ) . ')';
 946         }
 947
 948         public function buildGroupConcatField(
 949                 $delim, $table, $field, $conds = '', $join_conds = []
 950         ) {
 951                 $fld = "group_concat($field," . $this->addQuotes( $delim ) . ')';
 952
 953                 return '(' . $this->selectSQLText( $table, $fld, $conds, null, [], $join_conds ) . ')';
 954         }
 955
 956         /**
 957          * @param string $oldName
 958          * @param string $newName
 959          * @param bool $temporary
 960          * @param string $fname
 961          * @return bool|ResultWrapper
 962          * @throws RuntimeException
 963          */
 964         function duplicateTableStructure( $oldName, $newName, $temporary = false, $fname = __METHOD__ ) {
 965                 $res = $this->query( "SELECT sql FROM sqlite_master WHERE tbl_name=" .
 966                         $this->addQuotes( $oldName ) . " AND type='table'", $fname );
 967                 $obj = $this->fetchObject( $res );
 968                 if ( !$obj ) {
 969                         throw new RuntimeException( "Couldn't retrieve structure for table $oldName" );
 970                 }
 971                 $sql = $obj->sql;
 972                 $sql = preg_replace(
 973                         '/(?<=\W)"?' . preg_quote( trim( $this->addIdentifierQuotes( $oldName ), '"' ) ) . '"?(?=\W)/',
 974                         $this->addIdentifierQuotes( $newName ),
 975                         $sql,
 976                         1
 977                 );
 978                 if ( $temporary ) {
 979                         if ( preg_match( '/^\\s*CREATE\\s+VIRTUAL\\s+TABLE\b/i', $sql ) ) {
 980                                 $this->queryLogger->debug(
 981                                         "Table $oldName is virtual, can't create a temporary duplicate.\n" );
 982                         } else {
 983                                 $sql = str_replace( 'CREATE TABLE', 'CREATE TEMPORARY TABLE', $sql );
 984                         }
 985                 }
 986
 987                 $res = $this->query( $sql, $fname );
 988
 989                 // Take over indexes
 990                 $indexList = $this->query( 'PRAGMA INDEX_LIST(' . $this->addQuotes( $oldName ) . ')' );
 991                 foreach ( $indexList as $index ) {
 992                         if ( strpos( $index->name, 'sqlite_autoindex' ) === 0 ) {
 993                                 continue;
 994                         }
 995
 996                         if ( $index->unique ) {
 997                                 $sql = 'CREATE UNIQUE INDEX';
 998                         } else {
 999                                 $sql = 'CREATE INDEX';
1000                         }
1001                         // Try to come up with a new index name, given indexes have database scope in SQLite
1002                         $indexName = $newName . '_' . $index->name;
1003                         $sql .= ' ' . $indexName . ' ON ' . $newName;
1004
1005                         $indexInfo = $this->query( 'PRAGMA INDEX_INFO(' . $this->addQuotes( $index->name ) . ')' );
1006                         $fields = [];
1007                         foreach ( $indexInfo as $indexInfoRow ) {
1008                                 $fields[$indexInfoRow->seqno] = $indexInfoRow->name;
1009                         }
1010
1011                         $sql .= '(' . implode( ',', $fields ) . ')';
1012
1013                         $this->query( $sql );
1014                 }
1015
1016                 return $res;
1017         }
1018
1019         /**
1020          * List all tables on the database
1021          *
1022          * @param string $prefix Only show tables with this prefix, e.g. mw_
1023          * @param string $fname Calling function name
1024          *
1025          * @return array
1026          */
1027         function listTables( $prefix = null, $fname = __METHOD__ ) {
1028                 $result = $this->select(
1029                         'sqlite_master',
1030                         'name',
1031                         "type='table'"
1032                 );
1033
1034                 $endArray = [];
1035
1036                 foreach ( $result as $table ) {
1037                         $vars = get_object_vars( $table );
1038                         $table = array_pop( $vars );
1039
1040                         if ( !$prefix || strpos( $table, $prefix ) === 0 ) {
1041                                 if ( strpos( $table, 'sqlite_' ) !== 0 ) {
1042                                         $endArray[] = $table;
1043                                 }
1044                         }
1045                 }
1046
1047                 return $endArray;
1048         }
1049
1050         /**
1051          * Override due to no CASCADE support
1052          *
1053          * @param string $tableName
1054          * @param string $fName
1055          * @return bool|ResultWrapper
1056          * @throws DBReadOnlyError
1057          */
1058         public function dropTable( $tableName, $fName = __METHOD__ ) {
1059                 if ( !$this->tableExists( $tableName, $fName ) ) {
1060                         return false;
1061                 }
1062                 $sql = "DROP TABLE " . $this->tableName( $tableName );
1063
1064                 return $this->query( $sql, $fName );
1065         }
1066
1067         public function setTableAliases( array $aliases ) {
1068                 parent::setTableAliases( $aliases );
1069                 foreach ( $this->tableAliases as $params ) {
1070                         if ( isset( $this->alreadyAttached[$params['dbname']] ) ) {
1071                                 continue;
1072                         }
1073                         $this->attachDatabase( $params['dbname'] );
1074                         $this->alreadyAttached[$params['dbname']] = true;
1075                 }
1076         }
1077
1078         public function resetSequenceForTable( $table, $fname = __METHOD__ ) {
1079                 $encTable = $this->addIdentifierQuotes( 'sqlite_sequence' );
1080                 $encName = $this->addQuotes( $this->tableName( $table, 'raw' ) );
1081                 $this->query( "DELETE FROM $encTable WHERE name = $encName", $fname );
1082         }
1083
1084         public function databasesAreIndependent() {
1085                 return true;
1086         }
1087
1088         /**
1089          * @return string
1090          */
1091         public function __toString() {
1092                 return is_object( $this->conn )
1093                         ? 'SQLite ' . (string)$this->conn->getAttribute( PDO::ATTR_SERVER_VERSION )
1094                         : '(not connected)';
1095         }
1096
1097         /**
1098          * @return PDO
1099          */
1100         protected function getBindingHandle() {
1101                 return parent::getBindingHandle();
1102         }
1103 }
1104
1105 class_alias( DatabaseSqlite::class, 'DatabaseSqlite' );