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