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