includes/libs/rdbms/database/DatabaseSqlite.php

   1 <?php
   2 /**
   3  * This is the SQLite database abstraction layer.
   4  * See maintenance/sqlite/README for development notes and other specific information
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License along
  17  * with this program; if not, write to the Free Software Foundation, Inc.,
  18  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  19  * http://www.gnu.org/copyleft/gpl.html
  20  *
  21  * @file
  22  * @ingroup Database
  23  */
  24 namespace Wikimedia\Rdbms;
  25
  26 use PDO;
  27 use PDOException;
  28 use LockManager;
  29 use FSLockManager;
  30 use InvalidArgumentException;
  31 use RuntimeException;
  32 use stdClass;
  33
  34 /**
  35  * @ingroup Database
  36  */
  37 class DatabaseSqlite extends Database {
  38         /** @var bool Whether full text is enabled */
  39         private static $fulltextEnabled = null;
  40
  41         /** @var string Directory */
  42         protected $dbDir;
  43         /** @var string File name for SQLite database file */
  44         protected $dbPath;
  45         /** @var string Transaction mode */
  46         protected $trxMode;
  47
  48         /** @var int The number of rows affected as an integer */
  49         protected $lastAffectedRowCount;
  50         /** @var resource */
  51         protected $lastResultHandle;
  52
  53         /** @var PDO */
  54         protected $conn;
  55
  56         /** @var FSLockManager (hopefully on the same server as the DB) */
  57         protected $lockMgr;
  58
  59         /** @var array List of shared database already attached to this connection */
  60         private $alreadyAttached = [];
  61
  62         /**
  63          * Additional params include:
  64          *   - dbDirectory : directory containing the DB and the lock file directory
  65          *                   [defaults to $wgSQLiteDataDir]
  66          *   - dbFilePath  : use this to force the path of the DB file
  67          *   - trxMode     : one of (deferred, immediate, exclusive)
  68          * @param array $p
  69          */
  70         function __construct( array $p ) {
  71                 if ( isset( $p['dbFilePath'] ) ) {
  72                         $this->dbPath = $p['dbFilePath'];
  73                         $lockDomain = md5( $this->dbPath );
  74                 } elseif ( isset( $p['dbDirectory'] ) ) {
  75                         $this->dbDir = $p['dbDirectory'];
  76                         $lockDomain = $p['dbname'];
  77                 } else {
  78                         throw new InvalidArgumentException( "Need 'dbDirectory' or 'dbFilePath' parameter." );
  79                 }
  80
  81                 $this->trxMode = isset( $p['trxMode'] ) ? strtoupper( $p['trxMode'] ) : null;
  82                 if ( $this->trxMode &&
  83                         !in_array( $this->trxMode, [ 'DEFERRED', 'IMMEDIATE', 'EXCLUSIVE' ] )
  84                 ) {
  85                         $this->trxMode = null;
  86                         $this->queryLogger->warning( "Invalid SQLite transaction mode provided." );
  87                 }
  88
  89                 $this->lockMgr = new FSLockManager( [
  90                         'domain' => $lockDomain,
  91                         'lockDirectory' => "{$this->dbDir}/locks"
  92                 ] );
  93
  94                 parent::__construct( $p );
  95         }
  96
  97         protected static function getAttributes() {
  98                 return [ self::ATTR_DB_LEVEL_LOCKING => true ];
  99         }
 100
 101         /**
 102          * @param string $filename
 103          * @param array $p Options map; supports:
 104          *   - flags       : (same as __construct counterpart)
 105          *   - trxMode     : (same as __construct counterpart)
 106          *   - dbDirectory : (same as __construct counterpart)
 107          * @return DatabaseSqlite
 108          * @since 1.25
 109          */
 110         public static function newStandaloneInstance( $filename, array $p = [] ) {
 111                 $p['dbFilePath'] = $filename;
 112                 $p['schema'] = false;
 113                 $p['tablePrefix'] = '';
 114                 /** @var DatabaseSqlite $db */
 115                 $db = Database::factory( 'sqlite', $p );
 116
 117                 return $db;
 118         }
 119
 120         protected function doInitConnection() {
 121                 if ( $this->dbPath !== null ) {
 122                         // Standalone .sqlite file mode.
 123                         $this->openFile( $this->dbPath, $this->connectionParams['dbname'] );
 124                 } elseif ( $this->dbDir !== null ) {
 125                         // Stock wiki mode using standard file names per DB
 126                         if ( strlen( $this->connectionParams['dbname'] ) ) {
 127                                 $this->open(
 128                                         $this->connectionParams['host'],
 129                                         $this->connectionParams['user'],
 130                                         $this->connectionParams['password'],
 131                                         $this->connectionParams['dbname']
 132                                 );
 133                         } else {
 134                                 // Caller will manually call open() later?
 135                                 $this->connLogger->debug( __METHOD__ . ': no database opened.' );
 136                         }
 137                 } else {
 138                         throw new InvalidArgumentException( "Need 'dbDirectory' or 'dbFilePath' parameter." );
 139                 }
 140         }
 141
 142         /**
 143          * @return string
 144          */
 145         function getType() {
 146                 return 'sqlite';
 147         }
 148
 149         /**
 150          * @todo Check if it should be true like parent class
 151          *
 152          * @return bool
 153          */
 154         function implicitGroupby() {
 155                 return false;
 156         }
 157
 158         /** Open an SQLite database and return a resource handle to it
 159          *  NOTE: only $dbName is used, the other parameters are irrelevant for SQLite databases
 160          *
 161          * @param string $server
 162          * @param string $user Unused
 163          * @param string $pass
 164          * @param string $dbName
 165          *
 166          * @throws DBConnectionError
 167          * @return bool
 168          */
 169         function open( $server, $user, $pass, $dbName ) {
 170                 $this->close();
 171                 $fileName = self::generateFileName( $this->dbDir, $dbName );
 172                 if ( !is_readable( $fileName ) ) {
 173                         $this->conn = false;
 174                         throw new DBConnectionError( $this, "SQLite database not accessible" );
 175                 }
 176                 $this->openFile( $fileName, $dbName );
 177
 178                 return (bool)$this->conn;
 179         }
 180
 181         /**
 182          * Opens a database file
 183          *
 184          * @param string $fileName
 185          * @param string $dbName
 186          * @throws DBConnectionError
 187          * @return PDO|bool SQL connection or false if failed
 188          */
 189         protected function openFile( $fileName, $dbName ) {
 190                 $err = false;
 191
 192                 $this->dbPath = $fileName;
 193                 try {
 194                         if ( $this->flags & self::DBO_PERSISTENT ) {
 195                                 $this->conn = new PDO( "sqlite:$fileName", '', '',
 196                                         [ PDO::ATTR_PERSISTENT => true ] );
 197                         } else {
 198                                 $this->conn = new PDO( "sqlite:$fileName", '', '' );
 199                         }
 200                 } catch ( PDOException $e ) {
 201                         $err = $e->getMessage();
 202                 }
 203
 204                 if ( !$this->conn ) {
 205                         $this->queryLogger->debug( "DB connection error: $err\n" );
 206                         throw new DBConnectionError( $this, $err );
 207                 }
 208
 209                 $this->opened = is_object( $this->conn );
 210                 if ( $this->opened ) {
 211                         $this->dbName = $dbName;
 212                         # Set error codes only, don't raise exceptions
 213                         $this->conn->setAttribute( PDO::ATTR_ERRMODE, PDO::ERRMODE_SILENT );
 214                         # Enforce LIKE to be case sensitive, just like MySQL
 215                         $this->query( 'PRAGMA case_sensitive_like = 1' );
 216
 217                         return $this->conn;
 218                 }
 219
 220                 return false;
 221         }
 222
 223         public function selectDB( $db ) {
 224                 return false; // doesn't make sense
 225         }
 226
 227         /**
 228          * @return string SQLite DB file path
 229          * @since 1.25
 230          */
 231         public function getDbFilePath() {
 232                 return $this->dbPath;
 233         }
 234
 235         /**
 236          * Does not actually close the connection, just destroys the reference for GC to do its work
 237          * @return bool
 238          */
 239         protected function closeConnection() {
 240                 $this->conn = null;
 241
 242                 return true;
 243         }
 244
 245         /**
 246          * Generates a database file name. Explicitly public for installer.
 247          * @param string $dir Directory where database resides
 248          * @param string $dbName Database name
 249          * @return string
 250          */
 251         public static function generateFileName( $dir, $dbName ) {
 252                 return "$dir/$dbName.sqlite";
 253         }
 254
 255         /**
 256          * Check if the searchindext table is FTS enabled.
 257          * @return bool False if not enabled.
 258          */
 259         function checkForEnabledSearch() {
 260                 if ( self::$fulltextEnabled === null ) {
 261                         self::$fulltextEnabled = false;
 262                         $table = $this->tableName( 'searchindex' );
 263                         $res = $this->query( "SELECT sql FROM sqlite_master WHERE tbl_name = '$table'", __METHOD__ );
 264                         if ( $res ) {
 265                                 $row = $res->fetchRow();
 266                                 self::$fulltextEnabled = stristr( $row['sql'], 'fts' ) !== false;
 267                         }
 268                 }
 269
 270                 return self::$fulltextEnabled;
 271         }
 272
 273         /**
 274          * Returns version of currently supported SQLite fulltext search module or false if none present.
 275          * @return string
 276          */
 277         static function getFulltextSearchModule() {
 278                 static $cachedResult = null;
 279                 if ( $cachedResult !== null ) {
 280                         return $cachedResult;
 281                 }
 282                 $cachedResult = false;
 283                 $table = 'dummy_search_test';
 284
 285                 $db = self::newStandaloneInstance( ':memory:' );
 286                 if ( $db->query( "CREATE VIRTUAL TABLE $table USING FTS3(dummy_field)", __METHOD__, true ) ) {
 287                         $cachedResult = 'FTS3';
 288                 }
 289                 $db->close();
 290
 291                 return $cachedResult;
 292         }
 293
 294         /**
 295          * Attaches external database to our connection, see https://sqlite.org/lang_attach.html
 296          * for details.
 297          *
 298          * @param string $name Database name to be used in queries like
 299          *   SELECT foo FROM dbname.table
 300          * @param bool|string $file Database file name. If omitted, will be generated
 301          *   using $name and configured data directory
 302          * @param string $fname Calling function name
 303          * @return ResultWrapper
 304          */
 305         function attachDatabase( $name, $file = false, $fname = __METHOD__ ) {
 306                 if ( !$file ) {
 307                         $file = self::generateFileName( $this->dbDir, $name );
 308                 }
 309                 $file = $this->addQuotes( $file );
 310
 311                 return $this->query( "ATTACH DATABASE $file AS $name", $fname );
 312         }
 313
 314         function isWriteQuery( $sql ) {
 315                 return parent::isWriteQuery( $sql ) && !preg_match( '/^(ATTACH|PRAGMA)\b/i', $sql );
 316         }
 317
 318         protected function isTransactableQuery( $sql ) {
 319                 return parent::isTransactableQuery( $sql ) && !in_array(
 320                         $this->getQueryVerb( $sql ),
 321                         [ 'ATTACH', 'PRAGMA' ],
 322                         true
 323                 );
 324         }
 325
 326         /**
 327          * SQLite doesn't allow buffered results or data seeking etc, so we'll use fetchAll as the result
 328          *
 329          * @param string $sql
 330          * @return bool|ResultWrapper
 331          */
 332         protected function doQuery( $sql ) {
 333                 $res = $this->getBindingHandle()->query( $sql );
 334                 if ( $res === false ) {
 335                         return false;
 336                 }
 337
 338                 $r = $res instanceof ResultWrapper ? $res->result : $res;
 339                 $this->lastAffectedRowCount = $r->rowCount();
 340                 $res = new ResultWrapper( $this, $r->fetchAll() );
 341
 342                 return $res;
 343         }
 344
 345         /**
 346          * @param ResultWrapper|mixed $res
 347          */
 348         function freeResult( $res ) {
 349                 if ( $res instanceof ResultWrapper ) {
 350                         $res->result = null;
 351                 } else {
 352                         $res = null;
 353                 }
 354         }
 355
 356         /**
 357          * @param ResultWrapper|array $res
 358          * @return stdClass|bool
 359          */
 360         function fetchObject( $res ) {
 361                 if ( $res instanceof ResultWrapper ) {
 362                         $r =& $res->result;
 363                 } else {
 364                         $r =& $res;
 365                 }
 366
 367                 $cur = current( $r );
 368                 if ( is_array( $cur ) ) {
 369                         next( $r );
 370                         $obj = new stdClass;
 371                         foreach ( $cur as $k => $v ) {
 372                                 if ( !is_numeric( $k ) ) {
 373                                         $obj->$k = $v;
 374                                 }
 375                         }
 376
 377                         return $obj;
 378                 }
 379
 380                 return false;
 381         }
 382
 383         /**
 384          * @param ResultWrapper|mixed $res
 385          * @return array|bool
 386          */
 387         function fetchRow( $res ) {
 388                 if ( $res instanceof ResultWrapper ) {
 389                         $r =& $res->result;
 390                 } else {
 391                         $r =& $res;
 392                 }
 393                 $cur = current( $r );
 394                 if ( is_array( $cur ) ) {
 395                         next( $r );
 396
 397                         return $cur;
 398                 }
 399
 400                 return false;
 401         }
 402
 403         /**
 404          * The PDO::Statement class implements the array interface so count() will work
 405          *
 406          * @param ResultWrapper|array $res
 407          * @return int
 408          */
 409         function numRows( $res ) {
 410                 $r = $res instanceof ResultWrapper ? $res->result : $res;
 411
 412                 return count( $r );
 413         }
 414
 415         /**
 416          * @param ResultWrapper $res
 417          * @return int
 418          */
 419         function numFields( $res ) {
 420                 $r = $res instanceof ResultWrapper ? $res->result : $res;
 421                 if ( is_array( $r ) && count( $r ) > 0 ) {
 422                         // The size of the result array is twice the number of fields. (Bug: 65578)
 423                         return count( $r[0] ) / 2;
 424                 } else {
 425                         // If the result is empty return 0
 426                         return 0;
 427                 }
 428         }
 429
 430         /**
 431          * @param ResultWrapper $res
 432          * @param int $n
 433          * @return bool
 434          */
 435         function fieldName( $res, $n ) {
 436                 $r = $res instanceof ResultWrapper ? $res->result : $res;
 437                 if ( is_array( $r ) ) {
 438                         $keys = array_keys( $r[0] );
 439
 440                         return $keys[$n];
 441                 }
 442
 443                 return false;
 444         }
 445
 446         /**
 447          * Use MySQL's naming (accounts for prefix etc) but remove surrounding backticks
 448          *
 449          * @param string $name
 450          * @param string $format
 451          * @return string
 452          */
 453         function tableName( $name, $format = 'quoted' ) {
 454                 // table names starting with sqlite_ are reserved
 455                 if ( strpos( $name, 'sqlite_' ) === 0 ) {
 456                         return $name;
 457                 }
 458
 459                 return str_replace( '"', '', parent::tableName( $name, $format ) );
 460         }
 461
 462         /**
 463          * This must be called after nextSequenceVal
 464          *
 465          * @return int
 466          */
 467         function insertId() {
 468                 // PDO::lastInsertId yields a string :(
 469                 return intval( $this->getBindingHandle()->lastInsertId() );
 470         }
 471
 472         /**
 473          * @param ResultWrapper|array $res
 474          * @param int $row
 475          */
 476         function dataSeek( $res, $row ) {
 477                 if ( $res instanceof ResultWrapper ) {
 478                         $r =& $res->result;
 479                 } else {
 480                         $r =& $res;
 481                 }
 482                 reset( $r );
 483                 if ( $row > 0 ) {
 484                         for ( $i = 0; $i < $row; $i++ ) {
 485                                 next( $r );
 486                         }
 487                 }
 488         }
 489
 490         /**
 491          * @return string
 492          */
 493         function lastError() {
 494                 if ( !is_object( $this->conn ) ) {
 495                         return "Cannot return last error, no db connection";
 496                 }
 497                 $e = $this->conn->errorInfo();
 498
 499                 return $e[2] ?? '';
 500         }
 501
 502         /**
 503          * @return string
 504          */
 505         function lastErrno() {
 506                 if ( !is_object( $this->conn ) ) {
 507                         return "Cannot return last error, no db connection";
 508                 } else {
 509                         $info = $this->conn->errorInfo();
 510
 511                         return $info[1];
 512                 }
 513         }
 514
 515         /**
 516          * @return int
 517          */
 518         protected function fetchAffectedRowCount() {
 519                 return $this->lastAffectedRowCount;
 520         }
 521
 522         function tableExists( $table, $fname = __METHOD__ ) {
 523                 $tableRaw = $this->tableName( $table, 'raw' );
 524                 if ( isset( $this->sessionTempTables[$tableRaw] ) ) {
 525                         return true; // already known to exist
 526                 }
 527
 528                 $encTable = $this->addQuotes( $tableRaw );
 529                 $res = $this->query(
 530                         "SELECT 1 FROM sqlite_master WHERE type='table' AND name=$encTable" );
 531
 532                 return $res->numRows() ? true : false;
 533         }
 534
 535         /**
 536          * Returns information about an index
 537          * Returns false if the index does not exist
 538          * - if errors are explicitly ignored, returns NULL on failure
 539          *
 540          * @param string $table
 541          * @param string $index
 542          * @param string $fname
 543          * @return array|false
 544          */
 545         function indexInfo( $table, $index, $fname = __METHOD__ ) {
 546                 $sql = 'PRAGMA index_info(' . $this->addQuotes( $this->indexName( $index ) ) . ')';
 547                 $res = $this->query( $sql, $fname );
 548                 if ( !$res || $res->numRows() == 0 ) {
 549                         return false;
 550                 }
 551                 $info = [];
 552                 foreach ( $res as $row ) {
 553                         $info[] = $row->name;
 554                 }
 555
 556                 return $info;
 557         }
 558
 559         /**
 560          * @param string $table
 561          * @param string $index
 562          * @param string $fname
 563          * @return bool|null
 564          */
 565         function indexUnique( $table, $index, $fname = __METHOD__ ) {
 566                 $row = $this->selectRow( 'sqlite_master', '*',
 567                         [
 568                                 'type' => 'index',
 569                                 'name' => $this->indexName( $index ),
 570                         ], $fname );
 571                 if ( !$row || !isset( $row->sql ) ) {
 572                         return null;
 573                 }
 574
 575                 // $row->sql will be of the form CREATE [UNIQUE] INDEX ...
 576                 $indexPos = strpos( $row->sql, 'INDEX' );
 577                 if ( $indexPos === false ) {
 578                         return null;
 579                 }
 580                 $firstPart = substr( $row->sql, 0, $indexPos );
 581                 $options = explode( ' ', $firstPart );
 582
 583                 return in_array( 'UNIQUE', $options );
 584         }
 585
 586         /**
 587          * Filter the options used in SELECT statements
 588          *
 589          * @param array $options
 590          * @return array
 591          */
 592         function makeSelectOptions( $options ) {
 593                 foreach ( $options as $k => $v ) {
 594                         if ( is_numeric( $k ) && ( $v == 'FOR UPDATE' || $v == 'LOCK IN SHARE MODE' ) ) {
 595                                 $options[$k] = '';
 596                         }
 597                 }
 598
 599                 return parent::makeSelectOptions( $options );
 600         }
 601
 602         /**
 603          * @param array $options
 604          * @return array
 605          */
 606         protected function makeUpdateOptionsArray( $options ) {
 607                 $options = parent::makeUpdateOptionsArray( $options );
 608                 $options = self::fixIgnore( $options );
 609
 610                 return $options;
 611         }
 612
 613         /**
 614          * @param array $options
 615          * @return array
 616          */
 617         static function fixIgnore( $options ) {
 618                 # SQLite uses OR IGNORE not just IGNORE
 619                 foreach ( $options as $k => $v ) {
 620                         if ( $v == 'IGNORE' ) {
 621                                 $options[$k] = 'OR IGNORE';
 622                         }
 623                 }
 624
 625                 return $options;
 626         }
 627
 628         /**
 629          * @param array $options
 630          * @return string
 631          */
 632         function makeInsertOptions( $options ) {
 633                 $options = self::fixIgnore( $options );
 634
 635                 return parent::makeInsertOptions( $options );
 636         }
 637
 638         /**
 639          * Based on generic method (parent) with some prior SQLite-sepcific adjustments
 640          * @param string $table
 641          * @param array $a
 642          * @param string $fname
 643          * @param array $options
 644          * @return bool
 645          */
 646         function insert( $table, $a, $fname = __METHOD__, $options = [] ) {
 647                 if ( !count( $a ) ) {
 648                         return true;
 649                 }
 650
 651                 # SQLite can't handle multi-row inserts, so divide up into multiple single-row inserts
 652                 if ( isset( $a[0] ) && is_array( $a[0] ) ) {
 653                         $ret = true;
 654                         foreach ( $a as $v ) {
 655                                 if ( !parent::insert( $table, $v, "$fname/multi-row", $options ) ) {
 656                                         $ret = false;
 657                                 }
 658                         }
 659                 } else {
 660                         $ret = parent::insert( $table, $a, "$fname/single-row", $options );
 661                 }
 662
 663                 return $ret;
 664         }
 665
 666         /**
 667          * @param string $table
 668          * @param array $uniqueIndexes Unused
 669          * @param string|array $rows
 670          * @param string $fname
 671          * @return bool|ResultWrapper
 672          */
 673         function replace( $table, $uniqueIndexes, $rows, $fname = __METHOD__ ) {
 674                 if ( !count( $rows ) ) {
 675                         return true;
 676                 }
 677
 678                 # SQLite can't handle multi-row replaces, so divide up into multiple single-row queries
 679                 if ( isset( $rows[0] ) && is_array( $rows[0] ) ) {
 680                         $ret = true;
 681                         foreach ( $rows as $v ) {
 682                                 if ( !$this->nativeReplace( $table, $v, "$fname/multi-row" ) ) {
 683                                         $ret = false;
 684                                 }
 685                         }
 686                 } else {
 687                         $ret = $this->nativeReplace( $table, $rows, "$fname/single-row" );
 688                 }
 689
 690                 return $ret;
 691         }
 692
 693         /**
 694          * Returns the size of a text field, or -1 for "unlimited"
 695          * In SQLite this is SQLITE_MAX_LENGTH, by default 1GB. No way to query it though.
 696          *
 697          * @param string $table
 698          * @param string $field
 699          * @return int
 700          */
 701         function textFieldSize( $table, $field ) {
 702                 return -1;
 703         }
 704
 705         /**
 706          * @return bool
 707          */
 708         function unionSupportsOrderAndLimit() {
 709                 return false;
 710         }
 711
 712         /**
 713          * @param string[] $sqls
 714          * @param bool $all Whether to "UNION ALL" or not
 715          * @return string
 716          */
 717         function unionQueries( $sqls, $all ) {
 718                 $glue = $all ? ' UNION ALL ' : ' UNION ';
 719
 720                 return implode( $glue, $sqls );
 721         }
 722
 723         /**
 724          * @return bool
 725          */
 726         function wasDeadlock() {
 727                 return $this->lastErrno() == 5; // SQLITE_BUSY
 728         }
 729
 730         /**
 731          * @return bool
 732          */
 733         function wasReadOnlyError() {
 734                 return $this->lastErrno() == 8; // SQLITE_READONLY;
 735         }
 736
 737         public function wasConnectionError( $errno ) {
 738                 return $errno == 17; // SQLITE_SCHEMA;
 739         }
 740
 741         protected function wasKnownStatementRollbackError() {
 742                 // ON CONFLICT ROLLBACK clauses make it so that SQLITE_CONSTRAINT error is
 743                 // ambiguous with regard to whether it implies a ROLLBACK or an ABORT happened.
 744                 // https://sqlite.org/lang_createtable.html#uniqueconst
 745                 // https://sqlite.org/lang_conflict.html
 746                 return false;
 747         }
 748
 749         /**
 750          * @return string Wikitext of a link to the server software's web site
 751          */
 752         public function getSoftwareLink() {
 753                 return "[{{int:version-db-sqlite-url}} SQLite]";
 754         }
 755
 756         /**
 757          * @return string Version information from the database
 758          */
 759         function getServerVersion() {
 760                 $ver = $this->getBindingHandle()->getAttribute( PDO::ATTR_SERVER_VERSION );
 761
 762                 return $ver;
 763         }
 764
 765         /**
 766          * Get information about a given field
 767          * Returns false if the field does not exist.
 768          *
 769          * @param string $table
 770          * @param string $field
 771          * @return SQLiteField|bool False on failure
 772          */
 773         function fieldInfo( $table, $field ) {
 774                 $tableName = $this->tableName( $table );
 775                 $sql = 'PRAGMA table_info(' . $this->addQuotes( $tableName ) . ')';
 776                 $res = $this->query( $sql, __METHOD__ );
 777                 foreach ( $res as $row ) {
 778                         if ( $row->name == $field ) {
 779                                 return new SQLiteField( $row, $tableName );
 780                         }
 781                 }
 782
 783                 return false;
 784         }
 785
 786         protected function doBegin( $fname = '' ) {
 787                 if ( $this->trxMode ) {
 788                         $this->query( "BEGIN {$this->trxMode}", $fname );
 789                 } else {
 790                         $this->query( 'BEGIN', $fname );
 791                 }
 792                 $this->trxLevel = 1;
 793         }
 794
 795         /**
 796          * @param string $s
 797          * @return string
 798          */
 799         function strencode( $s ) {
 800                 return substr( $this->addQuotes( $s ), 1, -1 );
 801         }
 802
 803         /**
 804          * @param string $b
 805          * @return Blob
 806          */
 807         function encodeBlob( $b ) {
 808                 return new Blob( $b );
 809         }
 810
 811         /**
 812          * @param Blob|string $b
 813          * @return string
 814          */
 815         function decodeBlob( $b ) {
 816                 if ( $b instanceof Blob ) {
 817                         $b = $b->fetch();
 818                 }
 819
 820                 return $b;
 821         }
 822
 823         /**
 824          * @param string|int|null|bool|Blob $s
 825          * @return string|int
 826          */
 827         function addQuotes( $s ) {
 828                 if ( $s instanceof Blob ) {
 829                         return "x'" . bin2hex( $s->fetch() ) . "'";
 830                 } elseif ( is_bool( $s ) ) {
 831                         return (int)$s;
 832                 } elseif ( strpos( (string)$s, "\0" ) !== false ) {
 833                         // SQLite doesn't support \0 in strings, so use the hex representation as a workaround.
 834                         // This is a known limitation of SQLite's mprintf function which PDO
 835                         // should work around, but doesn't. I have reported this to php.net as bug #63419:
 836                         // https://bugs.php.net/bug.php?id=63419
 837                         // There was already a similar report for SQLite3::escapeString, bug #62361:
 838                         // https://bugs.php.net/bug.php?id=62361
 839                         // There is an additional bug regarding sorting this data after insert
 840                         // on older versions of sqlite shipped with ubuntu 12.04
 841                         // https://phabricator.wikimedia.org/T74367
 842                         $this->queryLogger->debug(
 843                                 __FUNCTION__ .
 844                                 ': Quoting value containing null byte. ' .
 845                                 'For consistency all binary data should have been ' .
 846                                 'first processed with self::encodeBlob()'
 847                         );
 848                         return "x'" . bin2hex( (string)$s ) . "'";
 849                 } else {
 850                         return $this->getBindingHandle()->quote( (string)$s );
 851                 }
 852         }
 853
 854         public function buildSubstring( $input, $startPosition, $length = null ) {
 855                 $this->assertBuildSubstringParams( $startPosition, $length );
 856                 $params = [ $input, $startPosition ];
 857                 if ( $length !== null ) {
 858                         $params[] = $length;
 859                 }
 860                 return 'SUBSTR(' . implode( ',', $params ) . ')';
 861         }
 862
 863         /**
 864          * @param string $field Field or column to cast
 865          * @return string
 866          * @since 1.28
 867          */
 868         public function buildStringCast( $field ) {
 869                 return 'CAST ( ' . $field . ' AS TEXT )';
 870         }
 871
 872         /**
 873          * No-op version of deadlockLoop
 874          *
 875          * @return mixed
 876          */
 877         public function deadlockLoop( /*...*/ ) {
 878                 $args = func_get_args();
 879                 $function = array_shift( $args );
 880
 881                 return $function( ...$args );
 882         }
 883
 884         /**
 885          * @param string $s
 886          * @return string
 887          */
 888         protected function replaceVars( $s ) {
 889                 $s = parent::replaceVars( $s );
 890                 if ( preg_match( '/^\s*(CREATE|ALTER) TABLE/i', $s ) ) {
 891                         // CREATE TABLE hacks to allow schema file sharing with MySQL
 892
 893                         // binary/varbinary column type -> blob
 894                         $s = preg_replace( '/\b(var)?binary(\(\d+\))/i', 'BLOB', $s );
 895                         // no such thing as unsigned
 896                         $s = preg_replace( '/\b(un)?signed\b/i', '', $s );
 897                         // INT -> INTEGER
 898                         $s = preg_replace( '/\b(tiny|small|medium|big|)int(\s*\(\s*\d+\s*\)|\b)/i', 'INTEGER', $s );
 899                         // floating point types -> REAL
 900                         $s = preg_replace(
 901                                 '/\b(float|double(\s+precision)?)(\s*\(\s*\d+\s*(,\s*\d+\s*)?\)|\b)/i',
 902                                 'REAL',
 903                                 $s
 904                         );
 905                         // varchar -> TEXT
 906                         $s = preg_replace( '/\b(var)?char\s*\(.*?\)/i', 'TEXT', $s );
 907                         // TEXT normalization
 908                         $s = preg_replace( '/\b(tiny|medium|long)text\b/i', 'TEXT', $s );
 909                         // BLOB normalization
 910                         $s = preg_replace( '/\b(tiny|small|medium|long|)blob\b/i', 'BLOB', $s );
 911                         // BOOL -> INTEGER
 912                         $s = preg_replace( '/\bbool(ean)?\b/i', 'INTEGER', $s );
 913                         // DATETIME -> TEXT
 914                         $s = preg_replace( '/\b(datetime|timestamp)\b/i', 'TEXT', $s );
 915                         // No ENUM type
 916                         $s = preg_replace( '/\benum\s*\([^)]*\)/i', 'TEXT', $s );
 917                         // binary collation type -> nothing
 918                         $s = preg_replace( '/\bbinary\b/i', '', $s );
 919                         // auto_increment -> autoincrement
 920                         $s = preg_replace( '/\bauto_increment\b/i', 'AUTOINCREMENT', $s );
 921                         // No explicit options
 922                         $s = preg_replace( '/\)[^);]*(;?)\s*$/', ')\1', $s );
 923                         // AUTOINCREMENT should immedidately follow PRIMARY KEY
 924                         $s = preg_replace( '/primary key (.*?) autoincrement/i', 'PRIMARY KEY AUTOINCREMENT $1', $s );
 925                 } elseif ( preg_match( '/^\s*CREATE (\s*(?:UNIQUE|FULLTEXT)\s+)?INDEX/i', $s ) ) {
 926                         // No truncated indexes
 927                         $s = preg_replace( '/\(\d+\)/', '', $s );
 928                         // No FULLTEXT
 929                         $s = preg_replace( '/\bfulltext\b/i', '', $s );
 930                 } elseif ( preg_match( '/^\s*DROP INDEX/i', $s ) ) {
 931                         // DROP INDEX is database-wide, not table-specific, so no ON <table> clause.
 932                         $s = preg_replace( '/\sON\s+[^\s]*/i', '', $s );
 933                 } elseif ( preg_match( '/^\s*INSERT IGNORE\b/i', $s ) ) {
 934                         // INSERT IGNORE --> INSERT OR IGNORE
 935                         $s = preg_replace( '/^\s*INSERT IGNORE\b/i', 'INSERT OR IGNORE', $s );
 936                 }
 937
 938                 return $s;
 939         }
 940
 941         public function lock( $lockName, $method, $timeout = 5 ) {
 942                 if ( !is_dir( "{$this->dbDir}/locks" ) ) { // create dir as needed
 943                         if ( !is_writable( $this->dbDir ) || !mkdir( "{$this->dbDir}/locks" ) ) {
 944                                 throw new DBError( $this, "Cannot create directory \"{$this->dbDir}/locks\"." );
 945                         }
 946                 }
 947
 948                 return $this->lockMgr->lock( [ $lockName ], LockManager::LOCK_EX, $timeout )->isOK();
 949         }
 950
 951         public function unlock( $lockName, $method ) {
 952                 return $this->lockMgr->unlock( [ $lockName ], LockManager::LOCK_EX )->isOK();
 953         }
 954
 955         /**
 956          * Build a concatenation list to feed into a SQL query
 957          *
 958          * @param string[] $stringList
 959          * @return string
 960          */
 961         function buildConcat( $stringList ) {
 962                 return '(' . implode( ') || (', $stringList ) . ')';
 963         }
 964
 965         public function buildGroupConcatField(
 966                 $delim, $table, $field, $conds = '', $join_conds = []
 967         ) {
 968                 $fld = "group_concat($field," . $this->addQuotes( $delim ) . ')';
 969
 970                 return '(' . $this->selectSQLText( $table, $fld, $conds, null, [], $join_conds ) . ')';
 971         }
 972
 973         /**
 974          * @param string $oldName
 975          * @param string $newName
 976          * @param bool $temporary
 977          * @param string $fname
 978          * @return bool|ResultWrapper
 979          * @throws RuntimeException
 980          */
 981         function duplicateTableStructure( $oldName, $newName, $temporary = false, $fname = __METHOD__ ) {
 982                 $res = $this->query( "SELECT sql FROM sqlite_master WHERE tbl_name=" .
 983                         $this->addQuotes( $oldName ) . " AND type='table'", $fname );
 984                 $obj = $this->fetchObject( $res );
 985                 if ( !$obj ) {
 986                         throw new RuntimeException( "Couldn't retrieve structure for table $oldName" );
 987                 }
 988                 $sql = $obj->sql;
 989                 $sql = preg_replace(
 990                         '/(?<=\W)"?' . preg_quote( trim( $this->addIdentifierQuotes( $oldName ), '"' ) ) . '"?(?=\W)/',
 991                         $this->addIdentifierQuotes( $newName ),
 992                         $sql,
 993                         1
 994                 );
 995                 if ( $temporary ) {
 996                         if ( preg_match( '/^\\s*CREATE\\s+VIRTUAL\\s+TABLE\b/i', $sql ) ) {
 997                                 $this->queryLogger->debug(
 998                                         "Table $oldName is virtual, can't create a temporary duplicate.\n" );
 999                         } else {
1000                                 $sql = str_replace( 'CREATE TABLE', 'CREATE TEMPORARY TABLE', $sql );
1001                         }
1002                 }
1003
1004                 $res = $this->query( $sql, $fname );
1005
1006                 // Take over indexes
1007                 $indexList = $this->query( 'PRAGMA INDEX_LIST(' . $this->addQuotes( $oldName ) . ')' );
1008                 foreach ( $indexList as $index ) {
1009                         if ( strpos( $index->name, 'sqlite_autoindex' ) === 0 ) {
1010                                 continue;
1011                         }
1012
1013                         if ( $index->unique ) {
1014                                 $sql = 'CREATE UNIQUE INDEX';
1015                         } else {
1016                                 $sql = 'CREATE INDEX';
1017                         }
1018                         // Try to come up with a new index name, given indexes have database scope in SQLite
1019                         $indexName = $newName . '_' . $index->name;
1020                         $sql .= ' ' . $indexName . ' ON ' . $newName;
1021
1022                         $indexInfo = $this->query( 'PRAGMA INDEX_INFO(' . $this->addQuotes( $index->name ) . ')' );
1023                         $fields = [];
1024                         foreach ( $indexInfo as $indexInfoRow ) {
1025                                 $fields[$indexInfoRow->seqno] = $indexInfoRow->name;
1026                         }
1027
1028                         $sql .= '(' . implode( ',', $fields ) . ')';
1029
1030                         $this->query( $sql );
1031                 }
1032
1033                 return $res;
1034         }
1035
1036         /**
1037          * List all tables on the database
1038          *
1039          * @param string $prefix Only show tables with this prefix, e.g. mw_
1040          * @param string $fname Calling function name
1041          *
1042          * @return array
1043          */
1044         function listTables( $prefix = null, $fname = __METHOD__ ) {
1045                 $result = $this->select(
1046                         'sqlite_master',
1047                         'name',
1048                         "type='table'"
1049                 );
1050
1051                 $endArray = [];
1052
1053                 foreach ( $result as $table ) {
1054                         $vars = get_object_vars( $table );
1055                         $table = array_pop( $vars );
1056
1057                         if ( !$prefix || strpos( $table, $prefix ) === 0 ) {
1058                                 if ( strpos( $table, 'sqlite_' ) !== 0 ) {
1059                                         $endArray[] = $table;
1060                                 }
1061                         }
1062                 }
1063
1064                 return $endArray;
1065         }
1066
1067         /**
1068          * Override due to no CASCADE support
1069          *
1070          * @param string $tableName
1071          * @param string $fName
1072          * @return bool|ResultWrapper
1073          * @throws DBReadOnlyError
1074          */
1075         public function dropTable( $tableName, $fName = __METHOD__ ) {
1076                 if ( !$this->tableExists( $tableName, $fName ) ) {
1077                         return false;
1078                 }
1079                 $sql = "DROP TABLE " . $this->tableName( $tableName );
1080
1081                 return $this->query( $sql, $fName );
1082         }
1083
1084         public function setTableAliases( array $aliases ) {
1085                 parent::setTableAliases( $aliases );
1086                 foreach ( $this->tableAliases as $params ) {
1087                         if ( isset( $this->alreadyAttached[$params['dbname']] ) ) {
1088                                 continue;
1089                         }
1090                         $this->attachDatabase( $params['dbname'] );
1091                         $this->alreadyAttached[$params['dbname']] = true;
1092                 }
1093         }
1094
1095         public function resetSequenceForTable( $table, $fname = __METHOD__ ) {
1096                 $encTable = $this->addIdentifierQuotes( 'sqlite_sequence' );
1097                 $encName = $this->addQuotes( $this->tableName( $table, 'raw' ) );
1098                 $this->query( "DELETE FROM $encTable WHERE name = $encName", $fname );
1099         }
1100
1101         public function databasesAreIndependent() {
1102                 return true;
1103         }
1104
1105         /**
1106          * @return string
1107          */
1108         public function __toString() {
1109                 return is_object( $this->conn )
1110                         ? 'SQLite ' . (string)$this->conn->getAttribute( PDO::ATTR_SERVER_VERSION )
1111                         : '(not connected)';
1112         }
1113
1114         /**
1115          * @return PDO
1116          */
1117         protected function getBindingHandle() {
1118                 return parent::getBindingHandle();
1119         }
1120 }
1121
1122 /**
1123  * @deprecated since 1.29
1124  */
1125 class_alias( DatabaseSqlite::class, 'DatabaseSqlite' );