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