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