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